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361 Cards in this Set
- Front
- Back
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list three types of cells found in skeletal muscle
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1. skeletal myocytes 3. endothelial cells of the vascular system 3. connnetive tissue fibroblasts
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what are the three cell types that comprise cardiac mucle
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cardiac myocyte, enodothelial cells of the endocardium, cardiac fibroblasts
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describe the hierarchy of the connetive tissue associated with skeletal muscle
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1. endomysium surrounds individual fibers 2. perimysium surrounds fasicles 3. epimysium surrounds the entrie muscle, visible at the gross level
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Describe the structures of blood vessels as they decrese in size and change from arterial to venous
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Heart=>elastic arteries=> muscular arteries=> small arteries and arterioles=> capillaries=> post capillary venule==> venules==> medium veins==> large veins==> heart
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what are the four phases of the cell cycle
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G1, S, G2, M
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describe how epithelia are classified basd on the number of cell layers
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simple=single layer; stratified=multiple layers of cells; pseudostratified=multiple layers of nuclei but all cells contact the basement membrane
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what is the overall function of the nuclear matrix
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organizes the genome into domains that regulate gene expression and cell replication
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Describe the characteristics of epitheial tissue structure
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polarized with apical (towars lumen), basal (towards basal lamina), and lateral surfaces, avascular, rest on basement membrane
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what are the four categories of connective tissue
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1. dense (regular and irregular) 2. loose 3. reticular 4. adipose
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Describe the structure of microtubules
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hollow cylinders with a 25nm outer diameter, they are composed of alpha and beta tubluin which form heterodimers that arrange as protofilaments. 13 protofilaments self-assemble to form a microtubule
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what type of epithelium is the epidermis
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stratified squamous
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list several types of intermediate filaments found in cells
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nuclear lains, vimentin, desmin, glial fibrillary acdic protein, keratin, neurofilaments
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List 5 functions of connective tissue
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1. mechanical support 2. exchange of metabolites 3. storage of energy 4. protecion against infection 5. repair
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Describe the "hierarchy" of skeletal muscle structure
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gross muscle> fascicles>myocytes> myofibrils>myofilaments
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how do cardiac cells differ from skeletal in terms of nuclei
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skeletal muscle cells have 100's of nuclei located at the periphery, cardiac muscle cells have 1-2 located cnerally
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How does the type of blood supply differ within the endomsium and perimysium
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endo-RBCs present within capillaries; peri-contains arterioles, venules, and nerves
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What are the three tunics that cover blood vessels
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adventitia, media, intima
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What occurs during the G1 phase? (what "choices" does the cell have)
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Senescence, differnetiation (G0), apoptosis, proliferation
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describe how epithelia are classified based on the shape of the surface cells
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squamous-flat, scale like ,width greater than height; cuboidal-cell width and height are about equal; columnar-cell height is much greater than cell width
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what are the three parts of the nuclear matrix
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1. nuclear envelope/ pore complex/ lamina 2. nucleolus 3. internal nuclear matrix
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Describe how epithelia are characterized based on the number of cellular layers
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1. simple= single layer 2. stratified=two more layers, only basal layer contacts BM (transitional epithelium is stratifed but apparent number of cell layers changes) 3. Pseudostratified=appears to have more than one layer but all cells contact the BM
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what type of collagen predominates in dense regular CT
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type I
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Desribe microtubule treadmilling
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occurs under equilibrium conditions in vitro, heterodimers pass from the plus end of the MT and fall of the minus end but the net length does not change
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what are the four layers of the epidermis superficial to deep
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Stratum: Corenum, granulosum, spinosum, basale
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What is the cause of emery-dreifuss muscular dystrophy
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autosomal dominant mutation of gene enconding lamins A/C (intermediate filaments), leads to peripheral heterocrhomatin detached from inner nuclear membrane, progressive muscle weakness, joint contractures, and cardiomyopathy
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Describe the structure and function of the ECM ground substance
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ground substance= hydrated gell with fibers embed, ground substance resists compression, fibers resist tensile forces
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How many nuclei does each skeletal muscle cell have and where are they located?
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hundreds, located at the periphery
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How do cardiac and skeletal muscle cell differ in terms of branching
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cardiac cells bifurate, skeletal cells do not unless there is pathology
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Where are the nuclei located in a normal skeletal muscle cell
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peripherally
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Describe the structure and function of teh tunica adventitia
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The outermost covering of blood vessels. Comprised mostly of CT contains the vasa vasorum and nervi vascularis
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What occurs during the S phase
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DNA synthesis, DNA 2N=> 4N, histones are synthesized
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how do epithelia obtain nutritents and eliminate waste given that they are avascular
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diffusion to/from blood vessels in the underlying connective tissue
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Describe the structureof the nucelar envelope
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A double membrane enclosing the perinuclear space which is continous with the ER. It is divided to segemetns limited by the nuclear pores.
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How might one disthinguish between a pseudostratified epithelium and a stratified epithelium
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-Each cell in the pesudo touches the BM, -stratified is never cilliated
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what type of CT is the reticular layer of the dermis
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dense, irregular
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Describe the role of GTP in microtubule polymerization and how it contributes to dynamic instability
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1. Polymerization at the plus end requires bound GTP which is hydrolyzed to GDP. 2. Dimeers are added most efficiently to an end capped with GTP. 3. WHEN THE RATE OF ADDITION OF DIMERS EXCCEDS THE RATE OF GTP HYDROLYSIS, A GTP CAP FORMS AND STABLIZES THE MOLECULE 4.When addition of dimers slows down, the GTP cap is lost and the MT depolymerizes
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How are thick and thin skin distinguished
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thick= S. corneum >50 cells, Thin <50
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How can intermediate filaments be used to type tumors
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Each type of tissue expresses diferenent types of IF's. Breast and GI primary cancers are keratin positive, sarcomas are vmentin positive
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Glycosaminoglycans (GAGs) are a component of the ground substance of the ECM. Describe their structure
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long, inflexible polysaccharide chains composed of repeating disaccharide units. One of the two sugar is always an amino sugar (N-acetylglucosamine or N-acetylgalactosamine) and the other is typically a uronic acid (glucuronic or iduronic)
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Describe the three layers of CT investment of skeletal muscle and what each layer invests
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1. epimysium-deep fascia that invests the whole, gross muscle 2. Perimysium-invests fascicles (buels of skeletal muscle fibers) 3. Endomysium-invets each fiber (skeletal myocyte), continous with the basal lamina, note that each cell has its own basal lamina
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what is the role o fintercalated dics in cardiac muscle
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intercellular attchments that enable myocytes to work together as if they were a syncytium. Dics on adjacent cells appear to form a staircase acrsos the myocardium because each disc has two perpnedicularly arranged parts
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How many nuclei does a skeletal myofiber hav
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many
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describe the structure and function of the tunica media
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Middle layer, most variable, contains smooth muscle cells and connective tissue
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What occurs during the G2 phase
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preparation for mitosis, centrosome duplicated, hyper-phosphorylation of histone and non-histone proteins
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where might you find simple squamous epithelium
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blood vessel lining
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Which structures are contained within the outer an dinner nuclear membranes
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outer membrane-faces cytoplasm, contains ribosomes for protein translation, inner membrane-contains intefral proteins that bind to the nuclear lamina which in turn attaches to the marginal heterohromatin
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how are epithelia characterized based on the shape of the cell
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1. squamous-flat 2. cuobid-cube shape 3. columnar
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Which tissue is more cellular epithelium or connective tissue
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epithelium
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on which end of the microtuble is assembly favored
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the plus end with GTP bound
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Compare thick and thin skin in terms of location, prescence of hair, arrector pilli, sebaecous and sweat glands
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location: thick is found on palms, soles, think is everywhere else; Stuff: thick does not have hair, AP, or sebaceous galnds, thin has all three; both types have sweat glands
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What is the role of keratin intermediate filaments in epidermolysis bullosa simplex
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genetically defective keratin filaments in skin epithelial cells renders the cells suceptible to mechanical rupturing producing blistering of the skin
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The amino sugar of GAGs (a component of the ECM ground substance) is usually sulfated and has a carboxyl group projecting from it. What is the consequence of this structure?
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Makes GAGs highly negativley charged, negative charge binds Na which osmotically attracts water in the matrix so it swells and occupies a lot of space. The result porus, hydrated gel serves as a cusion to absorb and disperse compressive loads
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Describe the overall properteis of skeletal musce CT investments. Where does it end? What is it continous with?
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Each of the three layers of Ct are in continuity. At the end of the muscle the investing CT is continous with the dense regular CT of tendons that attach muscle to bone
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What are the two parts of the intercalated disc. What do they do?
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1. transverse part- transmits contractile force, contains a fascia adherens, desmosomes, and actin filaments that butt into the half z bands, N-cadherins also present 2. Lateral part-transmits cell signals via gap junctions, made up of connexin molecules, desmosomes also present
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T/F skeletal muscle fibers branch
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false, note that cardiac do
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Describe the structure and function of the tunica intima
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The innermost convering of the blood vessels, a simple squamous endothelium with basal lamina and connective tissue, the cells are connected by tight junctions unitl they arrive at the capillary bed
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What occurs during M phase
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cell gorund up, nuclear membrane disappears, chromatin condenses into chromosomes, segregation of chromosomes
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Where might you find simple cuboidal epithelium
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kidney tubules, ducts of glands, surface of ovary
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What is the purpose of nuclear pores
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regulate passage of proteins inot and proteins and RNA out of the nucleus
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in a stratified epithelium, which cell should you look at to determine the name of the shpae
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the cells in the most superficial layer
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which tissure has more ECM epithelium or CT
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CT
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Describe the orientation of the MT's within the bipolar mitotic spindle
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The minus end of the MT is adjacent to the MTOC (centrosome), the plus ends are located at the chromosome kinetochores and the distal end of the astor MT's
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Describe the differnece between the epidermis-dermis interface in thick and thin skin
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thick=pegs and sockets, big wavy line ; thin=ridges and grooves, less wavy line
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Describe the protein structure of intermediate filament proteins
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Firbous molecules with conserved alpha-helical rod domains that provide for charge bonding of subunits into dimers and tetramers. They have variable carboxyl and amino terminal sequences which give functional diversity (keratin vs. lamins etc)
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What are the four main types of GAGs found in the ground substance of the ECM?
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1. hyaluronate 2. chondroitin sulfate/ dermatan sulfate 3. heparan sulfate/ heparin 4. keratan sulfate
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A centrally located skeletal muscle cell nuclei indiacates...
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pathology or injury, skeletal muscle nuclei are normally located at the periphery
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Compare the structure of atrial and ventricular myocytes
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atrial myoctes are smaller and contain less sarcomeric structure than ventricular. Atrial myocytes also contain membrane bound granules nearl the nuclei that contain ANF
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Describe the "banding" of skeletal muscle
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A band- thick and thin overlap, H band-thick only; I band-thin only, Z line-bisects I bands
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describe how the three tunics of the blood vessels are modified in the heart
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tunica adventitia=> epicardium, tunica media=> myocardium, tunica intima=> endocardium
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Which phase of the cycle cycle is the most variable and therefore determines the Tg
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G1 (S, G2, and M are relativley constant)
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where might you find simple columnar epithelium
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lines stomach, intestines, rectum, uterus, oviducts, ducts of some glands
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Describe the structure of nuclear pores
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Three strata of proteins arranged as an octamer (cytopasmic, nuclear, and middle). The strata contain nucleoporins
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Describe the processes of keratinization
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the outermost surface of a stratified epithelium becomes covered by the IF protein keratin rather than living cells, during maturation the cells acculuate keratin and lose their nuclei, the process provides a tough, water-resistant, non-living surface to protect the underyling tissue
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what type of connective tissue makes of the lamina propria of GI villi
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loose
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Anti-cancer drugs such as taxol and vinvblastine target microtubules. What is the mechanism behind these drugs?
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Taxol stabilizes microtubules and prevents depolarization at the end to mitosis, vinblastine prevents polymerization and the mitotic spindle can't assemble
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What are the two layers of the dermis
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1. papillary layer (superficial, loose CT) 2. Reticular (deep, irregular CT)
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Describe the polymerized structure of intermediate filaments
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The monomers assemble into dimers and then form staggered antiparallel tertramers packing to form a non-polarized, high-tensile strength insoluble filament.
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Hyaluronate is the predominant GAG in loose supporting tissues. How does it differ from other GAGs
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It is a non-sulfated, single disccharide unit consisting of long cahins. It does not form covalent links to protein molecules
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What structures defines the sarcomere
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The sarcomere is the area between sucessive Z lines which bisect I bands
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Compare the structures of SA/ AV node myocytes to that of Purkinje myocytes in the AV bundle of HIS
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node myocytes are small and embedded in dense CT they have few myofibrils and are adapted for impulse propgagation. Contrast this to the AV bundle of His that contains large purkinje myocytes that have few myofibrils, copious glycogen and inconspocuous intercalated discs.
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Thick filaments are composed of which molecule
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myosin
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What is the role of the epicardium
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Simple squamous mesothelium with connective tissue, the BVs and nerves of the heart enter here
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What types of external factors control the cell cylce? Activate vs inhibit?
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external factors include growth factors, cytokines, and hormones. Activating factors include FGFs, IGFs and Wnts. Inhibiting factors include TGFb
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where are the nuclei of simple columnar epithelial cells located
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closer to the basal side
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What is the purpose of the nuceloporins contained within the strata of the nuclear pores
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nucleoporins serve as docking sites for proteins that contains NLS's
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what is the glycocalyx
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carbohydrate rich complex on the extracellular surface of epithelial cells, functions in cellular protection and recongition
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list three componets of the non-firbrous ECM (ground substance)
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GAGs, proteoglycans, glycoproteins
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Give two examples of MTOC's, desribe their structure and role
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1. Centrioles within the centrosome 2.Centrioles within the basal body from which cilia extend, each of therse structures consist of triplet microtubuels that orient perpenducularly and are radially symmetric. they are very stable and do not show dynamic instability. This is also the site o fthe gamma tubulin ring complex that caps the - end of MTs at the MTOC to prevent disassembly
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what type of junction links epithelial keratinocytes
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desmosomes
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What mediates assembly/ disassebmley of intermediate filaments
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subunits phosphorylation (assembly) and dephosphorylation (disassembly)
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Describe the basic structure of proteoglycans, a component of the ground substance of the ECM. Where are they made?
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Sulfated GAG chains other than hyaluronate form covalent links with a protein core to form the proteoglycan. The GAGs attach to the core in the golgi.
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The A band is bisected by the H zone which inturn is bisected by the M line. What is the significance of the M line
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The M line contains MM-creatine kinase (MMCK) which provides energy for the cell
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what controls development of the purkinje fibers
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endothelial cells of the developing coronary arteries secrete endothelin which causes nearby cardiac myocytes to differentiate into purkinje fibers
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Name the three molecules found in thin filaments in skeletal muscle
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actin, tropomyosin, troponin
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What is the role of the myocardium
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contains cardiac myocytes and fibroblasts as well as the coronary arteries and veins
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describe role of each componnent of the delayed repsonse genes cdks and cyclins. How does their content change throughout the cell cycle?
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CDK=catalytic subunit, content is constant, Cyclin=regulatory subnunit, content increases during cell cycle
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where might you find pseudostratified columnar epithelium
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ciliated fm in respiratory tract, male reproductive tract
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Proteins larger than 40 kD must have an NLS to enter the nucleus. Describe the NLS sequence
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Short amino acid sequences that contain positivley charged basic amino acids (lysine, and arginine). The NLS must be on the protein's surface to be effective.
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Describe the structure of cilia
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anchored in a basal body/ centriole which contains nine triplets of MTs, from each basal body, nine doublets of peripheral MTs with dynein arms as well as two central MTs project outward into the cell membrane to form the projection, the 9+2 arrangement is called an axoneme
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what is the function of elastic fibers in loose CT
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distensiblity/ flexibility
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What is the role of gamma tubulin in MT structure and fxn
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gamma tubulin is part of the multi-protein complex called the gamma tubulin ring complex. The complex is invovled in initiation of polymerization of MT's at MTOC's. The gamma tubulin ring complex caps the minus end of the MT and prevents disassembly
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Where are the melanocytes of the skin located? What is the origin and function
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located in statum basale, derived from neural crest, synthesize and transport melanin
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Describe how actin filaments (F actin) form
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Globular (G) actin binds ATP and polymerizes into F actin filaments. Note that ATP hydrolysis and polymerization are not tightly coupled and an ATP cap favors stability of F actin
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Describe the structure of lycansggregan proteogy
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Many proteoglycans attach via a link protien to a hyaluronate backbone. these assemble in cartilage and CT
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In which bands of the muscle would you find think filaments
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Both the I and A bands
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What type of epithelium is the endocardium
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simple squamous
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during a concentric contraction which band of muscl decreases in width
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I band
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What is the role of the endocardium
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simple squamous endothelium/ basal lamina and CT, note that the conduction system is located in the "sub" endocardium
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Describe the internal factors that regulate the cell cycle
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composed of early and delayed response genes. Early response genes include myc and fos, delayed response genes are the cdks and cyclins
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WHat are the two forms of stratified squamous epithelium
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1. keratinized w/ surface layer of dea, anucleated cells filled with keratin, occurs in skin 2. nonkeratinized-surface layer of nucleated cells, mucous membrane in oral cavity, esophagous, vagina, anal canal, vocal folds (note these still have keatin IF's just no cornified layer)
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Describe how importins transport proteins into the nucelus
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Importin a binds to the NLS of a nuclear protein in the cytoplasm and the complex migrates to the nuclear pore. At the pore, importin B binds to a nucleoporin in the pore complex. This is followed by an energy dependent transport tthrough the popre. The protein is then released from importin and importin is cycled back through the pore to the cytoplasm.
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what is an axoneme
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the 9+2 MF arrangement characteristic of cilia (9 outer doubles and a two central microtubules)
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what type of CT would be found surronding the liver parenchyma
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reticular
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Describe the structure and function of the axoneme
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The axoneme is the cytoskeletal component of the cilium or flagellum it has a 9+2 pattern of MT's; a central pair and 9 outer doublets. The axoneme arises from the basal body that has a cross linked array of 0 triplet microtubles. The basal body is the MTOC for the cilium/ flagellum
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What constitudes the 'spines" seen in the stratum spinosum layer of the epidermis
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desomsomes
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Describe actin treadmilling
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IF both ends of F actin are ezxposed, polymerization will proceed until the concentration of free monomers exceeds Cc for the plus end but below for the minus end. At this state, there will be assembly at the plus end and disassembly at the minus end but the filament will maintain a constant length even though there is a net flux of subunits through the polymer.
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What are the functiosn of proteoglycans, a component of the ground substance of the ECM
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1. molecular iflters 2. binding sites for secreted growth factors, proteases, and protesae inhibitors (regulatory mechanism)
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What are the major thin filament proteins
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actin, troponin (3 isoforms) and tropomyosin
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what cell type is most abundant in the heart
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cardiac fibroblast
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what is the function of the neuromuscular spindle
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a stretch receptor that regulates muscle tone, note the presencs of intrafusal fibers surrounded by a capsule
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compare arteries and veins in erms of wall, lumen, and converings
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ateries have a thick wall and a small lumen, the tunica media is most developed with prominent elastin and SMCs, veins have thin walls with large lumens the tunica media is nondescript and the tunica adventitia is the thickest covering
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What are the 4 checkpoints that the cell must pass through to complete the cell cycle
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1. G1 phase activation (Cyclin D+ CDK4) 2. S phase activation (cyclins E and A + CDK2) 3. M phase activation (cyclin B CDK1), 4. anaphase (anaphase promoting complex)
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are nuclei present in the superficial cells of a non-keratinized stratified squamous epithelium?
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yes
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what sequence mediates nuclear export?
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leucine rich NES
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Describe the structure of microvilli (filaments)
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each microvillus contains actin microfilaments cross linked by villin that connect to a terminal web consisting of actin and spectin moleclues and intermediate filaments. Actin bundels are attached to the lateral plasma membrane via myosin and calmodulin.
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where are th enuceli and cytoplasmic organelles located in unilocular adipocytes
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peripherally around the lipid droplet
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Describe ciliary bending in terms of MT based motility. What is the motor? Energy?
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The motor is dynein (plus to minus) and it causes relative sliding between microtubules in the axoneme. ATP hydrolysis provides the energy for movement.
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Where are langerhans cells found? What is their source and function
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Langerhans cells are dendritic cells that phagocytose foreign particles in the superficial levels of the epiderms.They take up and process antigens. They are derived from the bone marrow and migrate to the skin
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Which state of actin (polymerized or free) is favored in the cell? how does the cell control the favored state
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Polymerization is highly favored because the free actin pool is greater than teh crtical concentration. To control polymerization, the cell uses binding proteins.
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Name a non-secreted proteoglycan and explain its purpose
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Syndecan remains attached to the cell membrane. The core proteins of syndecans act as TM proteins and are attached to actin filaments in the cytoskeleton and to collagen/ fibronectin in the ECM. Syndecans fibroblasts bind FGF and present it to the cell membrane FGF receptors
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In which bands of muscle would you find thick filaments
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A bands only
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What is the major fuel for cardiac myocytes
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triyglycerides stored in membrane-bound lipid droplets near the nuclues. Note also that there are many more mitochondria in skeletal cells than cardiac. Additionally, cardiac cells have a high myoglobin concentration and a rich vascular supply ==> continuously aerobic
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what is the relative size of smooth muscle cells vs. skeletal
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smooth are smaller
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describe some important featuers of teh tunica intima of large arteries
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tight junctions, pinocytotic vesicles transport nutrients from lumen to tissue, endothelila cells secrete factor VII
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Describe the G1 phase activation checkpont.
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Activation occurs by cyclin D CDK4, External growth factors activate cyclin D transcription. Cyclin D binds cdk 4 and the complex then phosphorylates Rb. Phosphorylated Rb releases its old on E2F-1 allowing E2F-1 to activate genes for cyclins E and A
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what is the major functional advantage of keratinized vs. non-keratinized epithelium
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keratinized are water resistant (skin)
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T/F protein and RNA transport are pore-specific
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false, the same pore can accomodate protein import, and protein/ RNA export
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Whre are tight junctions (zonula cculdens) located
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at the intercellualr juctions near the apical surface of the cell
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In which direction do each of the microtubule motors move?
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Dynein moves plus to minus, kinesin moves from minus to plus (hint: alphabetical)
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what is the differnce between an endocrine and exocrine gland
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endocrine-secrete product into bloodstream, exocrine-secrete product into duct
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What affect do mushroom toxins like cytochalasin and phalloidin have on actin filaments
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Phalloidins stabilize F actin by locking subunits together. Cytochalasins depolymize F actin by binding to the plus end.
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what causes progeria
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proteoglycan genetic disease, galactosyltransrease thermolability in fibroblasts resutls in failure of dermatan sulfate chain addition to proteoglycan=>premature aging, CT defects
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What is the major thick filament protein
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myosin
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Give two examples of cardiac muslce proteins that are diagnostic for MI's
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1. MB-CK 2. Troponin-I
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Describe the diameter/ shape of smooth muscle fibers cut in cross section
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The sectional diameter of the fibers is variable because the cell is spindle-shaped rather than cylindrical
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What is the main function of the large arteries
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maintain BP with recoil of elastic walls
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Describe the S phase activation checkpoint
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The restriction ponit is overcome by cyclinE+ CDK2 and the DNA is then duplicated. Cyclin A +CDK2 activates origins of DNA replication
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Where might you find stratified cuboidal/ columnar epithelia
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pharynx, larynx, urethra, conjuctiva, ducts of salivary, sweatk and mammary glands, anorectal junction
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What is the energy source of nucelar import
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Ran-GTP. In the nucleus, Ran-GTP binds to empty nuclear import receptors and cargo-bound export receptors which migrate to the cytoplasm. GTP is hydrolyzed to GDP releasing the bound moieties. The emtpy nuclear export recptors migrate back to the nuclues while the import reptors bind proteins with NLS's and then migrate back
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what is the function of the zonula occludens (tight junction)
|
forms a selectivley permeable barrer that surrounds each cell such that only water and small molecules are able to pass between cells, crucial to coerce transcellular rasnport across polarized cells instead of paracellualr transport between the cells
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Describe the basic structure of kinesin and the mechanism by which it moves along a MT
|
Kinesin has two heads which function as ATPass as well as a neck linker and a tail for the organelle. Kinesin binds the MT in the ADP which is then released for ATP. This leads to a conformational change which throws the ADP bound head fowrad. The ATP on the back head is hydrolyed to ADP and the ADP on the front heat is exchanged for ATP. This resets the cycle.
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What are the two parts of the eccrine sweat gland? WHat type of cells line each?
|
1. secretory part-simple cuboidal 2. duct part-stratified cuboidal
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List 4 classes of actin binding proteins
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1. regulatory 2. severing 3. cross-linking 4. motor (myosin)
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What are the two fibers that make up the fibrous portion of the ECM
|
1. collagens 2. Elastic fibers(elastin and fibrillin)
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Describe the structurend purpose of the T tubules
|
T tubules are invaginations of the sarcolemma that carry depolarization waves deep into the muscle cell. The T tublules run down inot the cell and abut the sarcoplasmic reticulum which envelops each myofibril
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Describe cardiac myocyte innervation
|
myocytes are innervated by the vagus nerve and autonomic nerves. Note that the heartbeat is intrinsic, innervation only regulates rate
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Because of their shape, a section through a given smooth mus fiber is (likely/ unlikely) to include the nuclues
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unlikely
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Which covering is most prominent in large veins
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tunica adventitia
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Desribe the M phase activation checkpoint
|
M phase is activated by cyclin B-CDK1. Cdc25 de-phosporylates CyclinB CDK1 allowing it to enter the nucleus where it then carriers out protein phosphorylation
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Where might you find transitional epithelium
|
baldder, renal pelvis, ureters, proximal urethra
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where is the nuclear lamina located
|
The lamina is sandwhiched between the marginal heterochromatin internally and the inner nuclear membrane externally. At its periphery lies the pore complexes within the nuclear envelope.
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Describe the chaceristic features of tight junctions (zonula occludens) on EM
|
pentalaminar dark-light-dark-light-dark apperance cause dby fusion of the outer membranes of the lipid bilayers of two adjacent cells
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Describe the orientation of MTs in axons. Which motors mediate transport to differnet parts of the cell?
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The minus ends are located at the celbody and the plus ends are located at the synpase. Transport toward the synpase (anterograde) is mediate by kinesin while transport towrad the cell body (retrograde) is mediated by dynein.
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Name and describe the three types of exocrine glands
|
1. holocrine-secrete whole cell 2. merocrine (eccrine)-exocytoses product 3. apocrine-secretes apical cytoplasm
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Describe the role of actin cross linking proteins. How do they work
|
Cross linking proteins give actin additional structure. The proteins have two actin binding sites sepaated by divergent intervening sequences. The proteins generate parallel and orthogonal actin arrays. Note that binding to the actin is inhibited by Ca. Examples include stress fivers which permit intercalation of mysion thick filamnets for contraction of connective tissues and formation of the cores of microvilli, orthagonal cross-linking produces an actin gel which dissovles into a sol and regulates cytoplasmic fluidity
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WHich cells synthesize and secrete collagen
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fibroblasts
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What is the "triad" found in skeletal muscle sectoins
|
Located at the A-I junction it is the combination of two SR membranes plus one T-tubule
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Describe the chronology of a heat attack
|
1. Myocyte death, immediate, release of MB-Ck and CTnI 2. Inflamation post 15 hrs, complement activation and cytokine release 3. WOund healing post 2-3 days mediated by cardiac fibroblasts 4. Angiogenesis post 2-4 days, induced by VGEF and FGF 5. Scar formation mediated by formation of collagen cross=links mediated by lysyl oxidase.
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where are smooth muscle cell nuclei located
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centrally
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describe the characteristic features of the medium arteries coverings
|
adventitia-prominent external lamina, media-SMCs, intima-elastic lamina
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Describe the Anaphase checkpoint
|
Anaphase is activated by the Anaphase Promoter Complex which contains ubiquitin
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How can you tell whether a bladder specimen is full or empty at the time of acqusition
|
Based on shpae transitional epithelial cells. when distended cells are flattened, when empty the superfical cells have a dome like apical surface "cobblestone"
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what is the function of the nuclear lamina
|
during interphase, it maintains the nuclues as a sphere, during mitosis the lamina breaks down due to hyper-phosphorylation of lamina proteins
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Describe the proteins invovled with tight junction structure
|
transmembrane tight junction proteins such as occludin, claudins, and JAM regulate the passage of solute molecues at the cell:cell interface, ZO proteins (specialized proteins in the sub-plasmalemmal plaque) facilitate the interaction of tight junction transmembrane proteins with the actin cytoskeleton
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Which motor would be used if a substances was being trasnported from the cell body to the synapse of a neuron
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Kinesin. The MT's of the axon have their minus end at the cell body and plus end at the synapse. Kinesin moves from minus to plus or from cell body to synapse.
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how are eccrine sweat glands innervated
|
SNS via cholinergics
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Describe the role of F actin in duchenne muscular dystrophy
|
Mutations alter or eliminate dyrophin binding to cortical F actin resulting in repeated cell membrane ruptures and muscle cell degernation.
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What form is collagen secreted into the matrix as? Describe the structure of this form
|
tropocollagen, a triple helix of three alpha chains. the alpha chain sequence is usually GLY-X-Y where X is commonly proline and Y is commonly hydroxyproline
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Describe the excitation phase of skeletal muscle contraction
|
Ach released from the motor neuron binds the Ach receptor and triggers a wave of depolarization down the sarcoleema. The wave travels deep into the muscle cell via the T-tubles. At the tra, the T-tubule depolarizes the SR. The SR releases stored Ca increasing the Ca concentration in the myofibrils
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What are the two sub-types of cardiac myocyte injury
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1. hypertrophy due to stress by chemical insult or high BP, characterized by re-expression of embryonic cardiac genes 2. ischemic injury caused by interrupton of the blood supply
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How many nuclei are associated with each smooth muslce myofiber
|
one
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what is the main function of medium arteries
|
mantain blood prsure via SMC contraction
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What type of proteins do proto-oncogenes encode (what is their normal function
|
Proto-oncogenes encode proteins that activate the cell cycle such as cell surface feceptors, second messengers, TF's, cyclins, and CDKs.
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how does the term for the layer between teh basal surface of epithelial cells and their underlying connective tissue change from EM to light microscope
|
light= basement membrane, EM=basal lamina
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Which genes encode the lamina proteins? What are their functions
|
Lamins A and C are splice products fo teh same LMNA gene, they interact with the marginal heterochromatin. Lamin b binds the inner nuclear membrane via LBR and fucntions to mediate the re-formation of the nuclear envelope after mitosis
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where is the zonula adherens (adherens junction) located
|
just beaneath the zonual occuldens
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Which motor would be used if a substances was being trasnported from the synapse to the cell body of a neuron
|
Dynein. The MT's of the axon have their minus end at the cell body and the plus end at the synapse. Dynein moves from plus end to minus end or from synapse to cell body.
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what is the origin of the hair folicle
|
cylidrical downgrowth of epithelia cells
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Describe the role of actin in amoeboid movement
|
The protruding edge of a crawling cell extends through dynamic assembly/ disassembly of actin filaments in a branching network.
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Describe the steps of collagen synthesis that occur within the fibroblast cell
|
Preprocollagen alpha chains are syntehsized on the RER. These chains contain propeptides at their amino and carboxy ends. Selected prolines and lysines within the chain are hydroxylated and glycosylated. Three preprocollagen chains assemble to form a procollagen triple helix which is then routed in vesicles to the cell surface via the golgi
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Describe the contraction phase of skeletal muscle contraction.
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In the thin filament Ca binds troponin C which causes tropomyosin to move and opens up the active site. The actin binds to the myosin head which contains bound ATP. ATP is hydrolyzed and the power stroke pulls the think filaments into the A band. This shortens the sarcomere and leads to contraction
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Describe the arrangemetn of smooth muscle cells aroudn the lumen of blood vessels
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Circular arrangement (not longitudinal) around the lumen
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Describe the formation of atherosclerotic plagues in medium arteries
|
Macrophges migrate to sites of endothelial damage and ingestis lipids, SMCS migrate to the tunica intima and proliferate and take up LDL, the two cells together create foam cells which make plagues
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When a proto-oncogene is mutated it is termed an oncognes. What does mutation of proto-oncogenes lead to and what are the consequences of this mutation
|
When a proto-oncogene is mutated in such a way that its activity is upregulated, the cell cycle is activate abberantly and there is uncontrolled progression leading to loss of cellular differentiation and increased proliferation.
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Which side of teh epithelial cell is adjacent to the basement membrane
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basal
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What is the cause of progeria?
|
deletion in part of the LMNA gene that generates the splice which creates mRNA encoding lamin A
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What are the three components of the zonula adherens
|
1. transmembrane linker proteins (cadherin) 2. sub-plasmalemmal plaque proteins (catenins, -actinin, vinculin) 3. cytoskeletal filaments (actin microfilaments)
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Describe the role of microtubule based motors in mitosis
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The motors are directed in such away that they create pushing and pulling forces. Pushing forces in the overlap zone and pulling foreces on asters create create the movement necessary for cell separation.
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what do pacinian corpuscles sense
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pain and pressure
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Describe th erole of actin filaments in macrphage phagocytosis
|
Dependent on actin based lamellipodia formation. Note that defecgtive phagocytosis occurs in Wiskott-Aldrich syndrome
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Describe the steps of collagen synthesis that occur after secretion into the extracellular space
|
The propeptides are cleaved from the procollagen triple helix to form tropocollagen. Tropocollagen molecues then assemble in a head to toe fashion to form collagen fibrils of types I, II, III, and VII. T fibrils are then further aggreagted into collagen fibers, a process mediated by type IX and XII fibril associated collagens that attach collagen fibrils together.
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Which bands change size during muscle contraction? Which stay the same.
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SInce only the thin filaments move during contraction, the I band shortens but the A band stays the same length. The thin filaments are pulled into the A band.
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How is the circular arrangement of smooth muscle cells around a blood vessel advantageous
|
enables regulation of blood vessel diameter and bloood flow
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Describe the distingushing features of medium veins
|
small valves made from folds of tunica intima
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What type of proteins do tumor supressor genes encode (what is their normal function)
|
tumor supressor genes encode proteins that inhibit the cell cycle including p21 (inhibits CDKs 2 and 4) and p53(activates p21 gene and directly initiates apoptosis)
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what attaches the basal membrane of epithelial cells to the basal lamina
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hemidesmosomes
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What is the purpose of the nucleolous
|
site of ribosomal RNA produciton via RNA pol I (christmas tree). Comprised of poritons of 10 chromoosomes for ~400 rRNA genes
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Describe the structure of the macula adherens (desmosome). What proteins are invovled
|
"spot weld" does not encircle cell, transmembrane linker proteins=nonclassical cadherin called desmogleins and desmocollins, the plaque contains desmoplakin, plakoglobin, and plakophilin, the intermediate filametn attached to the desomesome is keratin
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what do meissner's corupuscles sense
|
light touch
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What structural feature of the collagen molecule contriubtes to the formation and maintence of the fibrilar structure?
|
The fibrils are made up of tropocollagen molecules. Covalent bonds occur between the lysine and hydroxysine residues to neighboring tropocallgen molecules, the bonds help to maintain the structure
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Describe how skeletal muscle relaxes
|
An ion channel pumps Ca back into the SR. When the Ca level decreases, a fresh ATP binds the myosin and actin and myosin dissociate but cannot rebind for another power stroke.
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T/F cardiac myofibers normally branch
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TRUE
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Describe the distinguishing featuers of small arteries and arterioles
|
layers of SMCS in the tunica media, uptake up lipids by SMCS can narrow the lumen and cause hypertension.
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What is the result of a mutation in a tumor supressor gene
|
Mutations in tumor supressor genes that inhibit their ability to inhibit the cell cycle lead to uncontrolled progression through the cycle leading to increased proliferation and loss of differentiation
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list four types of plasma membrane specilizatiosn that help epithelial cells adhere and communicate with one another
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zonula occludens, zonula adherens, desmososmes, gap junctions
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What is the purpose of the internal nuclear matrix
|
consits of chromatin (DNA + histones +accessory proteins), contributes to the non-random order of the chromosomes, aids in DNA replication/ transcription (replicons)
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describe the structure of gap junctions
|
two connexons one in each of the adjoining cells each of which is made up of 6 subunits (juction has 12 connexin molecules total)
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describe psoriasis cause? location?
|
keratinocyte hyperproliferation, gives plaques of thickend epidermis on elbows, kness, gluteal cleft that bleed when scrapped
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Describe the "hierarchy" of collagen structure
|
collagen fiber>collagen fibril>tropocollagen>procollagen triple helix> 3 preoprocollagen chains
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Describe malignant hyperthermia
|
Autosomal dominant mutation of the RYR gene in the SR membrane. Dysregualtes Ca transport, when pts undergo anesthesia they undergo sustained muscle contraction and an increases in body temp. Tx with dantrolene, a muscle relaxant that inhibits Ca release through the RYR channel.
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How many nuclei are assoicated with each cardiac muscle myofiber
|
one or two
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What is unique about the coverings of capillaries compared to other blood vessels
|
no tunica adventitia or media
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Describe the sequence of apoptosis
|
1. Macrophages release TNF 2. TNF binds TNFR 3. pro-apoptotic signals induce leakiness of the outer membrane of the mitochonria 4. Cytochrome C escapes to the cytoplasm 5. Cyt C activates caspase which destroys organelles 6. Chromatin fragments and blebs are seen on the cell surface as the cell defoliates
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describe the appearance of the stratum corneum on light microscope
|
most superfical layer, thick and bright pink, no nuclei
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Hemidesmosomes are a basal membrane specialization. Describe their structure
|
half, desmosomes, integrins attach cell to the ECM components such as laminin, collagen, and fibronectin
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Descirbe bullous skin disease cause? types?
|
acquired autoimmune diesase with auto-Ab gainst cell attachment proteins, present with blisters 1. intraepidermal bullae=interrupt desomsomes between epithelial cells within epidermis (pemphigus foliaceus=desmoglein 1, pemphigus vulgaris=desmogelins 1 and 3) 2. Subepidermal Bullae- interupt hemidesmosomes between epidermis and dermis (bullous pemphigoid-BP180)
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Surcy is a deficiency of vitamin C. What affect does this disease have on collagen
|
Vit. C is necessary for hydroxylation of proline residues. Without this modification, the preprocollagen alpha chains are unable to form stable helicies in order to assemble into the preprocollagen triple helix.The tropocollagen fibers are incapable of aggregating into fibrils.
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Why does rigor mortis occur
|
There is no fresh ATP to pull the myosin head off the actin filament. The muscle is locked in the contracted state.
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Where are cardiac myofiber nuclei located
|
centrally
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Where are type I (continuous) capillaries found? Function? Structure?
|
Found in heart, skeletal muscle, CNS, lungs, tight junctions with pinocytotic vesicles (except CNS) for transport
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How can a mutation in an apoptotic regulating gene like bcl-2 lead to cancer
|
Bcl-2 is an anti-apoptotic factor. When mutated, Bcl-2 is abnormally actie resulting in too much inhibtion of apoptosis leading to tumor formation.
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describe the appearance of the stratum granulosum on light microscope
|
deep to S. corneum, superfical to S. spinosum, thin layer of cells containing dark purple granules
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Adhesion plaques are a basal membranes specialization, describe their structure
|
link to the ECM via integrins, similar to ozna adherens in that their plaque contains actinin and veniculin which in turn attaches to microfilaments
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|
What is the cause of acne vulgaris
|
overactive sebum production trapped in hair follicle with bacterial/ yeast involvement
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|
Describe 3 genetic diseases of collagen
|
Type I=osteogenesis imperfecta; Type II=Chondrodysplasias (cartilage joint deformities); Type III-Ehlers-Danlos syndrome (weak skin, fragile blood vessels, hypermobile joints)
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What two proteins compose elastic fibers found in the ECM
|
elastin and fibrilin
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Which CT layer invests fascicles
|
perimysium
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What two major cell-cell junctions are found in intercalated disks in cardiac muscle
|
fascia adherenes in the transverse part and gap junctions in the lateral part
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Where are type II capilaries found? Structure? Function?
|
found in endocrine organs, GI tract, kidney, fenestractions admit passage small molecules like hormones, nutrients, and ions
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Describe how a mutation in the telomerase gene can lead to cancer
|
in normal somatic cells, telmoerase is inhibited. If the gene is mutated and becomes active, the somatic cell can be immortal resultingin carcinogenesis
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Describe the apperance of the stratum spinosum on light microscope
|
deep to S. granulosum, superfical to S. basale, thick layer of cells, artificially separated, spiny projections represent extensions of cytoplasm of from adjacent cells still linked by desmososmes
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|
define junctional complex
|
the term applied to the group of cell membrane specializations along the lateral surface of epithelial cells inlcuding the zonula occludnes, zonula adherens, and macula adherens
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|
Describe contact allergic dermatitis
|
delayed immunological reaction of skin to foreign antigen, intercellular edema, lymphocytes infiltration, epidermal thickneing and scaling
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|
describthe structure of elastin
|
protein rich in glycine, lysine, and proline, chains are covalently lniked by lysine residues
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which CT layer invets myocytes
|
endomysium
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|
What is the functional significance of intercalated disks
|
cell adhesion and electrical coupling of adjacent cardiac myofibers
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|
Where are type III (discontinous) capilaries found? structure? Function?
|
bone marrow, liver, spleen, endothelial cells and basal lamina are not continous, large cells can pass through, filter out whole RBCs
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|
Explain how metastasis can be targeted for cancer Tx
|
inhibitors of metalloproteases such as TIMPS can prevent the spread of cancer by preventing the cells from "eating through" the ECM
|
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|
describe the apperance of the stratum basale on light microscope
|
deepest layer of the epidermis
|
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|
what is the difference between a carcinoma and and adenocarcinoma
|
carcinoma=malignant tumor of epithelial cells, adenocarinoma=malignant tumor of epithelial glandular cells
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|
describe the structure of arrector pili muscles
|
obliquely oriented bundles of smooth m. which insert into CT
|
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|
Describe the structure of elastic fibers in the ECM
|
In the ECM, elastin is assembled into elastic fibers consisting of an elastin core surrounded by a sheath of microfibrils which are composed of fibrillin
|
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|
Describe the appearance of myofibrils in a cross section of skeletal muscle
|
red dots in the sarcoplasm
|
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|
Describe the shape of cardiac fibers in cross section
|
variable fiber diameter because of branching
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|
Give two examples of the secretory functions of capillary endothelial cells
|
1. vasoactive factors (endothelin=vasoconstrictor, NO=vasorelaxant) 2. Growth factors (FGF, PDFG, interleukins)
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|
Explain how angiogenesis can be targeted for cancer Tx
|
tumors require a blood supply to live, prevention of angiogenesis can starve the tumor
|
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|
name the layers of teh epidermis from superficial to deep
|
Stratum: corneum, granulosum, spinosum, basale
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How could you stain to tell whether a tumor was epithelial, glial, muscle, or CT origin
|
epithelial=keratin, glial=GFAP, muslce=desmin, CT=vimentin
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|
what is the mode of secretion of sebaceous glands
|
holocrine- entire cell is shed
|
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|
What is the cause of marfan syndrome
|
mutations in fibrllin gene, reuptured aneurysms of the root of the aorta
|
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|
Describe the arrangement of thick and thin filaments in each myofibril in a skeletal muscle at EM lelvel
|
Six thin filaments surround one thick filament
|
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|
what are the three layers of blood vessel walls
|
tunica intima, tunica media, tunica adventitia
|
|
|
lymphatics are present in all tissues except
|
bone marrow and CNS
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|
Give two examples of how specific molecules can be targeted in cancer cells
|
1. neutralizing monoclonal antibodies 2. siRNAS
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|
Describe the shape of the junction between the epidermal ridges and the dermal papillae in thick skin
|
Large depressions and elevations/ very wavy (contrast to smaller amplitude wavy line of thin skin)
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|
what cytoskeletal filaments interact with zonula occludens (tight jucnctions)
|
actin microfilaments
|
|
|
what is the mode of secretion of eccrine sweat glands
|
merocrine/ eccrine= exocytosis
|
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|
What are two two adhesive glycoproteins found in the ECM that serve to link the basal lamina to the cell membrane
|
1. Fibronectin 2. laminin
|
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|
What are the four energy sources used by skeletal muslce
|
ATP, creatine phosphate, glycogen, fatty acids
|
|
|
describe the tunica intima in terms of location and composition
|
borders the lumen of the vessel, consists of simple squamous endothelium and subendothelial connective tissue
|
|
|
List some receptors and cognates that are invovled in angiogenesis
|
VEGFR/VEGF, FGFR/FGF, TIE-2/ angiopoietin
|
|
|
explain how RNAi therapy works
|
1. siRNA complementary to the pathogenic RNA is introduced into the cell 2. siRNA binds RISC 3. RISC/siRNA complex base-pairs w/ pathogenic RNA 4. RISC cleaves up pathogenic RNA and eliminates it
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|
What is the function of Pacinian corpuscle
|
sensory receptor responsive to course touch and vibration
|
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|
what cytoskeletal filaments interact with zonula adherens (adherens junction)
|
actin microfilaments
|
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|
Describe the rule of 9's in terms of burns
|
Body segments= 9% for upper limb, 18% for lower limb, ant trunk, post trunk, 9% for H&N 1% for perineum, 30-40% surface is life threatening, 75% is almost always fatal
|
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|
What is the function of integrins
|
Integrins are the "linker" proteins that connect the cell cytoskeleton with proteins in the ECM, attachment of cells to matrix components can be modulated by controlling integrin expression on the cell surface
|
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|
Describe type I skeletal muscle fibers
|
red, enriched in mitochondria and myoglobin for FA oxidation and oxidative metabolism, supply continous contaction, aka slow twitch
|
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|
describe the tunica media in terms of location and composition
|
middle layer between intima and adventitia (not that in arterie, the internal elastic lamina separates the intima and media), consists of vascular smooth muscle and fenestrated elastic laminae
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|
|
Inhibitors of blood vessel formation are present as components of the ECM in adacent tissue. Give two examples
|
angiostatin (derivative of plasminogen) and endostatin (derived fom collagen XVIII)
|
|
|
what are two potential problems associated with siRNA therapy
|
1. must prevent off target effects 2. must develop delivery methods to tumor in vivo
|
|
|
What is the function of Meissner's corpuscles and where are they found?
|
Sensitive to light touch, found in papillae of the skin of the finger tips, nipples, genitalia, and lips
|
|
|
what cytoskeletal filaments interact with macula adherens (desmosomes)
|
intermediate filaments (keratin)
|
|
|
Describe the structure of integrins
|
Transmembrane heterodimers with alpha and beta subunits. The carboxyl end of the subunit binds actin filaments in the cytoskeleton while the amino end binds proteins in the ECM
|
|
|
Describe type II skeletal muscle fibers
|
less myoglboin, modified for rapid, discontinous contraction.
|
|
|
describe the tunica adventitia in terms of location
|
outermost layer
|
|
|
Describe the process of angiogenesis
|
1. activation 2. proteolysis of ECM 3. distruption of cell adhesion 4. migration and chemotaxis 5. proliferation 6. permeability 7. inhibiton of growth
|
|
|
describe the dermal-epidermal junction in thin skin
|
slightly wavy line (contrast to the very wavy and irregular line of thick skin)
|
|
|
what cytoskeletal filaments interact with adhesion plaques on the basement membrane
|
actin microfilaments
|
|
|
Describe the structure of fibronectin
|
large glycoprotein heterodimer containing collagen, heparin, and integrin binding domains separated by fledible hinge proteins. Ecell binding site is an RGD tripeptide recognized by integrins.
|
|
|
What is the niche of resident adult stem cells used for muscle regeneration
|
reside between the sarcolemma and the basla lamina of the myocyte
|
|
|
Describe the location of the internal and external elastic lamina
|
internal-separates the tunica intima and tunica media, found in arteries. external elastic lamina found in large artereis, separates media and adventitia
|
|
|
what are the two layers of the dermis
|
paipllary layer just benath the epidermis, deeper reticular layer
|
|
|
t/f gap junctions ineract with the cytoskeleton
|
false, there is no cytoskeletal protein associated with connexons
|
|
|
Describe the "sandwhich" that fibronectin creates to establish structural continuity betwee nthe cytoskeleton and ECM
|
actin binds to integrins,integrins bind to fibronectin, fibronectin binds to collagen and heparin sulfate in the ECM
|
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|
describe the properties and purpose of sateite cells (skeletal myoblasts)/ how does muslce regeneration occur
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stem cells resting in the G0 phase, when the basal lamina of the myocye is damaged, it rleases growth factor signals that induce the myoblasts to re-enter the cell cycle. THe cells then withdraw from the cell cycle and then fuse together forming myotubes. The myotubes then differntiate and reform the muslce tissue. Note that myostatin released by mature myocytes limits the growth of myoblasts
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where are the vessel endothelial cell nuceli in relation to the lumen of the vessel
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the nuclei bulge toward the lumen of the vessel
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the duct portion of an eccrine sweat gland is made up of what type of epithelium
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stratified cuboidal
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what are the plaque components of zonula occludens (tight junctions
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ZO's 1-3
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WHat is the function of laminin
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major component of basal lamina, forms links bween cell membranes an dother constituents of the basal lamina
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List 4 proposed interventions for DMD
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1. celllular therapy with stem cells 2. gene therapy 3. oral drugs used to circumvent stop signals in mutated gene 4. inhibition of myostatin
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what is the functional significance of fenestrated elastic laminae in elastic arteries
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the elastic tissue helps maintain constant arterial pressure by stretching during ventricular contraction and recoiling during ventricular relaxation
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What NT is used for inneravtion of eccrine sweat glands
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Ach
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what are the plaque components of teh zonula adherens
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<-actinin, vinculin
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describe the structure of laminin
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three large polypetide chains, the beta chains wrap around the alpha chain forming a cross like pattern of one long and three short chains held together by disulfide bonds
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The nuclei within the tunica media belong to what cell type
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smooth muscle cells
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Describe the shape of sebaceous gland cells
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collectiosn of large cells with small, found, centrally located nuclei and a cytoplasm that appears foamy
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what are the plaque components of hemidesomsomes
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desmoplakin-like
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Describe the structure of the basal lamina
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sheet like netowrk of ECM that acts as an interface between the epithelia and the surrounding CT. Coposed of type IV collagen, the proteoglycan perlecan heparan sulfate, and the adhesive glycoproteins laminin and entactin
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what is the function of the vasa vasorum
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blood cells that provide nutrients to cells within the tunica media of large vessels
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what type of muscle are arrector pili
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smooth
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what are the plaue components of macula adherens (desmosomes)
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desmoplakin, plakoglobin, plakophilin
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Name three functions of the basal lamina
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1. molecular filter 2. selective barrier to cells 3. scaffolding for regeneration
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describe the characteristics of an arteriole
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external diameter ladventitiaess than 100um, wall thickness=lumen diameter, little or no subendothelial CT, 2-5 SMC layers in media, no external elastic lamina, very thin
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What division of the ANS innervates arrecto pili muscles
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sympathetic
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what are the plaque proteins associated with gap junctions
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none
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How is the basal lamina attached to cells (what is the sandwhich)
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anchoring fibrils of type VII collagen attach basal lamina to ECM, integrins attach laminin within the basal lamina and anchor it to the cell membrane
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describe continuous capillaries
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endothelial cells itghly attached by junctional complexes, brain, peripheral nerves
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the external root sheath is formed by which layer of the skin
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the epidermis invginates from the surface to form the external root sheath, it is surrounded by the glassy membrane
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What is the transmembrane linker protein of zonula occuludens
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claudins, occludin, JAM
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How do cells penetrate the ECM in order to mediate degradation
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release matrix metaloproteinases and serine proteases which degrade collagen, laminin, and fibronectin
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describe fenestrated capillaries
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pores within the endothelail cells, kidneys, intestines, endocrine glands
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What is the transmembrane linker protein of zonula adherens
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cadherin
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How is matrix degradation regulated?
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Cells at the margins of active degradation secrete Peptide Tissue Inhibitors of Metalloproteases (TIMPs) and serine protease inhibitors (serpins) that dissure in the ECM and bind to proteoglycans. These enzymes limit the action of proteases that degraded the ECM
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describe sinsoidal capillaries
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wide lumens, fenestrations, gaps between endothelial cells, discontinous basal lamina, bone marrow, liver, lymphoid organs, some endocrine glands, conforms to channel created by parenchyal cells of suornding tissue
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what is the trnasmembrane linker protein of macula adherens (desmosomes)
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desmogelin, desmocollin
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what is the role of fibroblasts
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most aundant cells of CT, synthesize almost all of the ECM of connective tissue
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What is the transmembrane linker protien of hemidemosomes
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integrin
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Describe the structure of fibroblasts
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lie parallel to the long axis of collagen fibers so shape and orientation reflecst the composition and stress of surronding environment. Large ovoid nucleus contains patches of heterochromatin and 1 or 2 nuceloi. Cytoplasm has prominent golgi, slender mitochondria, and abudant rER (lots of protein sysnthesis). No basal lamina
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what is the transmembrane linker protien of adhesion plaques
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integrin
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Myofibroblasts are modified fibroblasts. What is their function?
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Characteristics of fibroblasts and smooth muscle cells. Aboundant in areas of wound healing, contain actin and dense bodies to allow for contraction and skrinkage of scar tissue. also found in periodotal ligament
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what is the transmembrane linker protein of gap junctions
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connexin
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Describe the structural diferneces between white and brown adipose cells
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white-unilocular; brown-multilocular
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What is the functional type of zonula occludens
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occulding juction
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What type of collagen forms the septa that paritions fat (white adipose) into lobules
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type III
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what is the functional type of zonula adherens
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anchoring junction
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what are the two differnet types of obesity
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hypertorphic, hypercellular
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what is the functional type of macual adhernes
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anchoring junction
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What is the role of leptin?
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Regulates adipose mass, secreted by adipocytes and binds to appetide centers in the hypothalamus to activate the sympathetics to release NE and mobilze FA's. People w/o leptin have fuge appetie, weight gain
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what is the functional type of hemidesmosomes
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anchoring junction
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What is the role of monocytes/ marocphages
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phagocytosis, antigen presentation
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what is the functional type of gap junctions
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communicationg junction
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describe the appearance of macrophages
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kidney shaped indented nucleus, abundant lysosomes (primary and secondary), large juxtanuclear gloci,
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what is the role of neutrophils
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relased during inflammatory process, phagocytose and digest bacterai=> pus
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describe the appearance of neutrophils
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multilobulated nucleus and non-sepcific cytoplasmic granules (primary lysosomes)
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What is the role of eosinophils
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paracytes, allergic inflammation, phagocytosis
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describe the apperance of eosinophils
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multilobulated nuclues, eosinophilic specific granules
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describe the apperaance of lymphocytes
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small dark cells containing a dark round nucleus and thin rim of cytoplasm
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describe the apperance of plasma cells
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round nucelus with clock face pattern of heterochromatin and exnteisive basophillic cytoplasm of rER
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what is the role of plasma cells
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derived from B lymphocytes that have interacted with antigen and secrete antibodies.
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what is the role of mast cells
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mediate inflammatory processes and hypersensitivity reactions, bind IgE and degranute to release histamine=>hay ferver, leukotrienes=>asthmatics
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describe the apperance of mast cells
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large cells filled with basophilic granules, small round nucelus
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Describe the two forms of embryonic connective tissue that are only found in the developoing embryo
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1. mesenchymal-gives rise to loose CT, gel-like substance containing reticular fibers 2. mucous-found in umbilica cord, jelly-like marix composed of hyauronic acid and small amounts of fibrillar collagens
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What are the four types general connective tissue
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1. lose 2. irregular dense 3. regular dense 4. reticular
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Describe the structure of loose connetive tissue
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looose arrangemetn of fibers and disperesed cells imbedded in a gel like substnace
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WHere is loose connective tissue found? What is its function
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found under epithelia of the body, packing organs and surrounding capillaries, functions to wrap and cuoin organs and hold tissues together. macrophages munch bacteria
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describe the structure of irregular dense CT
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irregularly arranged collagen fibers and few cells.
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Where is irregular dense CT found and what is its function
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reticular layer of dermis of skin, submucosa of digestive track, fibrous capusles of visceral organs and joints, functions to withstand tension exerted in multiple directiosn and provides structural strength
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Describe the structure of regular dense CT
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coarse collagen bundles densely packed and oriented into parallel cylinders
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Where is regular dense CT found and what is its function
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tendons, ligaments, aponeurosis, cornea (type I, perpendicular), withstand tensile force in one direction
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Describe the structure of reticular CT
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netowrk of reicular fibers (collagen type III) in loose ground substance
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Where is reticular CT found? Fxn?
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surronding parenchyma of liver, lymph nodes, spleen, pancreas, supports the parenchyma of the organ
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