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581 Cards in this Set

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Epithelia can come from all 3 germ layers, where would these be?
Ectoderm epithelia is all the outside layers. Endoderm epithelia is lining the GI tract. Mesoderm epithelia is lining the CV system, urogenital system and serous cavities.
What location do you not find epithelia?
Over articular surfaces
Is epithelium vascular or avascular?
AVASCULAR, gets it's nutrition from the vascular underlying CT.
What are the IF's found in epithelia? What are the exceptions?
Keratin
Endothelium and mesothelium are vimentin
What is the mucocutaneous junction?
When inside epithelium meets outside epithelium like in the rectum-anus junction
What are the 2 examples of mesothelium?
Pericardium, pleura and peritoneum
Locations of simple squamous epithelium? Functions? Defining characteristics?
Alveoli, pleura, pericardium, blood vessels, loop of Henle, lympathics and parietal layer of Bowman's capsule.
Functions: Exchange
Flat nucleus of single layer of cells.
Locations of simple cuboidal epithelium? Functions? Defining characteristics?
Kidney tubules, thyroid follicles, ducts of secretory unit.
Function: secretion and absorption.
Round nucleus of single layer of cells.
Locations of simple non-ciliated columnar epithelium? Defining characteristics?
Small and large intestines, GB and large ducts of glands.
Single layer of cells with a basally located oval nucleus and no cilia on the surface. In addition, covered with striated border microvilli and goblet cells.
Locations of simple ciliated columnar epithelium? Defining characteristics?
Oviduct, uterus, efferent ducts and small bronchi.
Single layer of cells with a basally located oval nucleus and the surface covered with cilia.
TRUE/FALSE YOU NEVER FIND CILIA IN STRATIFIED EPITHELIA?
TRUE!!! Only simple epithelia have cilia. Pseudostratified epithelia are classed as simple epithelia.
Locations of pseudostratified ciliated epithelium? Defining characteristics?
Trachea and bronchi
All cells touch the BM but not all touch the surface. Have an oval shaped nucleus and goblet cells
Locations of pseudostratified non-ciliated epithelium? Defining characteristics?
Epididymis
DON'T BE CONFUSED, these have stereocilia to increase absorption. There are also NO goblet cells in the non-ciliated version.
What is 1 thing to remember when classifying stratified epithelia?
THE SURFACE CELLS ARE THE ONLY ONES THAT ARE IMPORTANT
Locations of stratified squamous keratinized epithelium? Function? Defining characteristics?
Dry surface epithelia like skin.
Protection from abrasion
There are no nuclei in the outer layer which usually looks separated from the surface during fixing.
Locations of stratified squamous non-keratinized epithelium? Function? Defining characteristics?
Wet surfaces of the oral cavity, esophagus and vagina.
Protection from abrasion.
Flat nuclei are found in the outer layer.
What is the predominant cell junction in stratified squamous epithelia?
DESMOSOMES to resist abrasion.
Locations of stratified cuboidal epithelium? Function? Defining characteristics?
Ducts of sweat glands, male urethra and esophageal glands (VERY RARE).
Protection, limited secretion and absorption.
2 layers of cells with round nuclei
Locations of stratified columnar epithelium? Defining characteristics?
Large excretory ducts of some glands, male urethra and conjunctiva of the eye.
2 layers of cells with oval nuclei
Locations of transitional epithelium? Function? Defining characteristics?
Ureters and urinary bladder.
Permit distention
Binucleated surface cells is defining because this will look like stratified squamous non-keratinized. In addition, the surface is puffy like clouds.
Which cells can divide in simple vs. stratified epithelium?
All simple epithelia retain the ability to divide. Only the basal layer of stratified epithelia retain the ability to divide.
What is metaplasia?
When cells of a certain region change into a different but still normal looking type of cells. E.g. stratified squamous in the trachea
What is dysplasia?
Abnormal looking tissue due to damage. This is still reversible.
What is anaplasia?
Non-reversible abnormal looking tissue which is usually cancer.
Why is cancer of the glands called adenocarcinoma and what is cancer of the epithelia called?
Glands are classified as epithelium and cancer of the epithelium is called carcinoma, therefore glandular cancer is adenocarcinoma.
What are the different shapes of the secretory units of glands?
Tubular
Acinar
Alveolar
Tubuloalveolar/tubuloacinar
The pancreas is a good example of what type of gland secretion?
Serous secretion which is watery, protein rich substance
Goblet cells are a good example of what type of gland secretion?
Mucus secretion which is rich in glycoproteins. This secretion is merocrine although it looks like holocrine
What is special about mixed mucoserous glands?
They have serous demilunes with intercellular secretory canaliculi.
What type of secretory product do sebaceous glands release?
Sebum which is filled with wax, cholesterol, TGL's and cell debri. Remember this is holocrine secretion.
What is the difference between apocrine sweat glands and eccrine sweat glands?
Apocrine product is similar to eccrine sweat except it is filled with protein and this allows bacteria to thrive. This makes apocrine sweat smelly and these are found in axilla and groin areas.
What product do eccrine sweat glands release?
Sweat which is a hypotonic water solution with very low protein
What product is released from mammary glands?
Milk which contains minerals, electrolytes, carbs, IgA and proteins
What method is milk released by?
Protein portion is released by merocrine but lipid portion is released apocrine.
4 things to know about intercellular secretory canaliculi?
They are modified ECF spaces
They have microvilli
They are closed off by ZO's
The product eventually gets into a true duct.
What are the 2 types of CT found in stroma of glands?
Dense irregular CT with type I collagen is found in capsule, septa and trabeculae.
Loose connective tissue with type III collagen is found surrounding each acinus.
What is the difference in lining between intralobular ducts and interlobular ducts?
Intralobular are lined with simple cuboidal or columnar.
Interlobular are lined with stratified columnar.
What is the difference between an intercalated duct and a striated duct?
Intercalated ducts are lined by simple cuboidal and connect acinus to striated duct.
Striated ducts are simple columnar and have basal infoldings making them striated.
What is the germ layer of origin of myoepithelial cells and why is this weird?
Germ layer of origin is ectoderm so have keratin intermediate filaments BUT THEY ARE SMOOTH MUSCLE CELLS.
True/False Myoepithelial cells have cell junctions?
YES, they have hemidesmosomes, desmosomes and gap junctions. ON THE EXAM!!!
What is the difference in location of channels in epithelia vs. normal cells?
Na/K pump and K channel in basolateral membrane. Na channel in apical membrane for absorption. In normal cells, these channels are randomly distributed.
What is the sequence for electrogenic Na absorption?
1) K channels in basolateral membrane create negative cell interior.
2) With a negative interior, the driving force for Na is an electrical force directed towards the inside of the cell.
3) The Na/K pump is always working and pushes this Na out of the cell.
4) A transluminal potential develops with the lumen negative. This pushes Cl through paracellular pathway into blood.
5) Some Na goes paracellular back to the lumen.
What is the point of electrogenic Na absorption?
To create an osmotic gradient which favors the absorption of water with the help of aquaporins.
What is the sequence for electrogenic Cl secretion?
1) K leak channel creates a negative cell interior.
2) Cl is driven out of cell into lumen by electrical gradient.
3) Na/K/2Cl pump in basal membrane replenishes Cl which leaked out apical surface.
4) Transluminal potential with lumen negative draws Na into lumen and water follows.
What is the point of the Na/K/2Cl pump?
The pump moves 2Cl and 1Na along their concentration gradients into the cell to replenish the Cl lost from the apical surface. The K moves solely to maintain electrical neutrality but is actually moving against conc. gradient.
What do we need in the alveoli to maintain a fluid layer?
Due to cardiovascular hydrostatic pressure, there is always fluid in the alveoli. Our purpose is to reduce this fluid and this is done with electrogenic Na reabsorption.
Which cell is responsible for maintaining the fluid balance in the alveoli?
Type II alveolar cell.
What do we need in the trachea to maintain a fluid layer?
Because the cardiovascular system hydrostatic pressure is insignificant, fluid must be created for the trachea. This is done with electrogenic Cl secretion.
Why does CF affect the trachea?
In order to maintain a fluid layer in the trachea, electrogenic Cl secretion occurs. This Cl channel is the CFTR channel which is deficient in CF. W/o the channel, the mucus is very thick.
Why do patients with CF have salty sweat if Cl secretion is altered?
The Cl channel in the secretory unit of the gland is not a CFTR channel. These patients can still secrete Cl no problem.
The CFTR channel is reversed in the duct and so they can't reabsorb the Cl fast enough.
Why use the CFTR channel for Cl reabsorption in the sweat duct?
The sweat duct still reabsorbs Na through the electrogenic method, however Cl does not move paracellular, this is not quick enough. The CFTR channel is inserted into the membrane to make this absorption quicker.
IT IS STILL ELECTROGENIC Na REABSORPTION.
What is the difference between epithelia and CT extracellular matrix?
Epithelia only have basal lamina whereas CT have extensive ECM.
What are the 4 cells that are not classified as CT normally but still contain VIMENTIN?
Endothelium, mesothelium, mast cells and smooth muscle.
Is connective tissue vascular or avascular?
It is very vascular as it provides blood to the avascular epithelium under which it sits.
What do mesenchymal cells have that is unusual for CT?
Gap junctions. Cell junctions are not very numerous in CT.
What are the 4 types of loose connective tissue?
Areolar, reticular, adipose and lamina propria
Classify? Chief packing material CT around the body
Adipose tissue which the primary cell being an adipocyte.
Classify? CT with a large amount of type III collagen
Reticular CT
Where would one find reticular CT and what cells does it contain?
Bone marrow, spleen and lymph nodes. Reticular CT basically forms the hematopoeitic and lymphoid tissue stroma.
Reticular CT contains reticular cells which make the type III collagen.
Where would one find lamina propria?
As part of the mucosa of respiratory, digestive, reproductive and urinary tracts.
What is specific to areolar CT?
It has all 3 types of fibers: collagen, elastic and reticular. It also has a crapload of resident cells such as macrophages, fibroblasts, mast cells, plasma cells and adipocytes.
What composes the ground substance of areolar CT?
Hyaluronic acid, dermatan, keratan and chondroitin sulfate.
What is the difference btw dense and loose CT?
Dense CT has lots of type I collagen fibers and the key resident cell is the fibroblast.
Where would you find dense regular CT?
Tendons, ligaments, deep fascia and aponeuroses.
Where would you find dense irregular CT?
Reticular layer of dermis, periosteum, perichondrium, organ capsules, septa, trabeculae, perineurium and perimysium.
What causes myxedema?
Lack of thyroxine increases the synthesis of GAGS which increases tissue colloid osmotic pressure thereby drawing water into the ISF.
What are the 8 resident cells of CT?
Fibroblasts, mast cells, plasma cells, adipocytes, macrophages, endothelial cells, pericytes and vascular smooth muscle cells.
What is the function of the fibroblast?
Secrete procollagen, proelastin, GAGS and all components of the ECM.
What 2 things are required for fibroblasts to grow?
Fibroblast growth factor (FGF).
Transforming growth factor.
What special proteoglycan is found in the membrane of a fibroblast?
Syndecan which is chondroitin and heparan sulfate.
Is it high or low thyroid hormone that causes GAGs to accumulate?
Low thyroxine levels.
What are the 3 differences between fibroblasts and fibrocytes?
Fibroblasts - high metabolic activity. Fibrocytes - darker nucleus due to condensed euchromatin.
Fibroblasts - actively secreting, fibrocytes don't secrete.
Fibroblasts - actively dividing, fibrocytes may or may not divide.
What is a myofibroblast?
A fibroblast with actin and myosin found in areas of wound healing. Have an external lamina
What is another name for fixed macrophages? What about lung, liver, bone and CNS macrophages?
Histiocytes
Alveolar macrophage
Kupffer cells
Osteoclasts
Microglia
4 characteristics of macrophages?
Come from monocytes
Have lots of lysosomes, golgi and RER
High phagocytosis
Have Fc receptors for binding of ab and complement
What are the 3 functions of macrophages in CT?
Turn over the old ECM material.
Act as APC's (antigen presenting cells)
Release IL-1, TNF-a, chemotactic factors and enzymes (lysozymes and collagenase)
What do macrophages release to activate T-helper cells?
IL-1
What intermediate filaments do endothelial cells contain?
Vimentin and Desmin
Where do you find pericytes?
Around continuous capillaries and post-capillary venules
What is the function of pericytes?
Release vasoactive substances to change capillary diameter. Contain smooth muscle to act like muscular layer of bv.
What replaces pericytes in all other blood vessels other than capillaries and post-capillary venules?
Vascular smooth muscle cells
What is the precursor to the adipocyte?
Lipoblast
What is special about white adipose tissue?
The adipocytes are surrounded by a basal lamina which is the only CT cell to have this.
What connects unilocular adipocytes to one another?
Reticular fibers
Can unilocular adipocytes divide?
Not while they have fat in them.
When are the 3 times that adipocytes can divide and form?
Last 3 months of fetal life
5 years postnatal
Pre-puberty due to the estrogen
What do sympathetics do to brown adipose tissue?
Skin sensory receptors sense cold, send impulse to CNS whereby sympathetics to B3 receptors on Brown adipose are activated by Nepi. This activates hormone sensitive lipase which breaks down TGL's so that they can be used for oxidation. The mitochondria do not use these for energy production but rather heat production.
What allows brown adipose tissue to make heat?
Thermogenin (UCP-1) is an uncoupling agent which prevents ATP from being made in the mitochondria.
Where is lipoprotein lipase found?
It is found lining endothelial cells but it is made by adipocytes
What is the effect of insulin on adipocytes?
It inhibits hormone sensitive lipase to prevent TGL breakdown. It also activates the GLUT4 receptor to increase blood glucose uptake. This is because adipose tissue can't use glycerol to synthesize fats.
What do prostaglandins do to adipose tissue?
Inhibit hormone sensitive lipase to prevent TGL breakdown
List 3 activators of hormone sensitive lipase and what is the mechanism.
ACTH, glucagon and Nepi (sympathetics)
They increase levels of cAMP.
Why do obese people have hypertension?
Capillaries in adipose tissue are particularly long which causes increased TPR thereby leading to hypertension.
What is the function of leptin and where is it made?
Hormone made by adipose tissue which goes to the hypothalamus to decrease apetite.
What is the subQ fat that is found all over an infant's body called?
Panniculus adiposus
What are the locations of brown adipose in the adult?
Axilla, neck, mediastinum and kidney hilus
Which is highly vascularized brown or white adipose tissue?
BOTH and both receive sympathetic stimulation
What is the immediate precursor of the mast cell?
Monocyte
What is found in the granules of a mast cell?
Primary mediators: Histamine, eosinophil chemotactic factor and neutrophil chemotactic factor.
What are the secondary mediators of a mast cell and what is their function?
Leukotrienes C4 and D4 - produce vascular and bronchospasm.
Prostaglandin D2 - produce bronchospasm.
What is the origin of the secondary mediators of a mast cell?
The leukotrienes and prostaglandins come from arachidonic acid which came from phospholipase A2 breaking down DAG.
How do you activate mast cells?
First exposure to antigen (bee venom) binds IgE and causes it to move to mast cell PM.
Second exposure - antigen binds to IgE on the mast cell surface and activates adenylate cyclase. This increases cAMP which causes Ca2+ release. The Ca2+ release causes the granules to fuse and be released.
What is compound exocytosis?
It is when the granules of the mast cell fuse together before being released.
How do you cause mast cells to release their secondary mediators?
Phospholipase C converts PIP2 into IP3 and DAG. The DAG is converted into arachidonic acid with phospholipase A2 which can then be converted into leukotrienes C4 and D4 and prostaglandin D2.
Why is the plasma cell cytoplasm basophillic?
Due to RER
What accounts for the perinuclear clear area of the plasma cell?
Large Golgi apparatus
What are the red granules of the eosinophil?
Lysosomes
Where is mucosa found?
Reproductive, respiratory, digestive and urinary systems.
What makes us a serosa?
Loose CT with overlying mesothelium
What is special about synovial membranes?
They do not have an epithelium. Contain 2 cell types. Type A - macrophages and Type B - fibroblasts (make synovial fluid)
What is synovial fluid made of?
Hyaluronic acid and lubricin
What are the components of skin?
Stratified squamous keratinized epithelium and dense irregular CT.
What are the components of mucosa?
Simple columnar or pseudostratified epithelium with lamina propria.
What are the components of serosa?
Mesothelium and submesothelial layer (loose CT)
In term of blood vessels, epithelium is to connective tissue as ....
Cartilage is to bone.
CARTILAGE NOT VASCULAR
BONE VERY VASCULAR
What is the composition of cartilage ground substance?
Aggrecan (chondroitin and keratan sulfate), and chondronectin (glycoprotein). There is no mineral component like bone
What is the composition of bone ground substance?
Chondroitin and keratan sulfate, osteocalcin and osteopontin. Finally, hydroxyapatite is the mineralized component of bone.
What types of collagen are found in cartilage? What about bone?
Type I and II collagen
Type I collagen
Which resident cells of cartilage can divide? How about bone?
Chondroblasts and cytes can divide.
Only osteoprogenitor cells can divide. Osteoblasts and cytes cannot divide.
True/False Cartilage has no nerves, blood or lymphatics?
TRUE
What are the locations of elastic cartilage?
Pinna, auditory tube, vocal cords, epiglottis
Where would I find hyaline cartilage?
Nasal cartilage, thyroid cartilage, tracheal and bronchial cartilage, ARTICULAR CARTILAGE and costal cartilage.
You also find hyaline cartilage in the epiphyseal plates of long bones.
Fibrocartilage is found in 4 locations, what are they?
Intervertebral discs, pubic symphysis, muscle insertions and menisci
Why is it called hyaline cartilage?
Because the type II collagen doesn't form fibers, it forms fibrils which make it look glassy. Hyaline means glassy.
What type of collagen is found in hyaline cartilage?
Type II collagen
Chondronectin has 4 binding sites, what are they?
Type II collagen
Integrins of chondroblasts and cytes
Chondroitin sulfate
Hyaluronic acid
What is the perichondrium?
2 layers surrounding cartilage. It has a fibrous layer and a chondrogenic layer.
What is the fibrous layer of the perichondrium composed of?
It is dense irregular CT with lots of blood vessels, type I collagen and elastic fibers. The resident cell is a fibroblast.
What is the purpose of the chondrogenic layer of the perichondrium?
The chondrogenic layer is where we find chondroblasts which allow for appositional growth of cartilage.
What are 2 things special about articular cartilage?
IT HAS NO PERICHONDRIUM
The cells are lined up in rows instead of nests and the only other place that this occurs is the epiphyseal plate.
What is the type of collagen in mesenchyme?
TYPE III reticular fibers.
Discuss how hyaline cartilage is made?
1) Begins as mesenchyme with these cells making reticular fibers and hyaluronic acid.
2) Precartilage forms when these cells stop making hyaluronic acid and start making aggrecan. The cells cluster into groups called centers of chondrification.
3) Mesenchymal cells are now chondroblasts which secrete matrix and trap themselves in lacunae. Once this occurs, they are chondrocytes.
4) Chondrocytes divide and form territorial matrix.
When chondrocytes divide and form secondary lacunae this is called?
Interstitial growth and only happens in young cartilage.
How does articular cartilage divide?
ONLY BY INTERSTITIAL GROWTH because there is no perichondrium
Which hormones increase cartilage growth rate?
Thyroid, testosterone and GH
Which hormones decrease cartilage growth rate?
Cortisone, hydrocortisone and estradiol
Hypovitaminosis A causes?
Reduced epiphyseal plate width
Hypervitaminosis A causes?
Accelerated epiphyseal plate ossification stunting growth
What does hypovitaminosis C do?
Inhibits matrix formation and deforms the epiphyses
If the chondrocytes can proliferate but the matrix can't calcify, what could be the problem?
Hypovitaminosis D
What is the predominant fiber type in elastic cartilage?
TYPE II COLLAGEN, don't say elastic fibers although these are very prevalent.
Why does elastic cartilage cause thrombosis?
Fibrillin in the elastic cartilage is one of the most thrombogenic substances in the body.
How does fibrocartilage develop?
Fibroblasts of dense regular CT mature into chondrocytes. IT MAY AS WELL BE CALLED DENSE REGULAR CT.
What are the characteristics of fibrocartilage?
No perichondrium
Chondrocytes are in rows
Type I collagen
What is osteoid?
The organic component of bone which has type I collagen and ground substance (chondroitin sulfate and osteocalcin)
What is the composition of ground substance in osteoid?
Chondroitin sulfate and osteocalcin.
What does osteocalcin do for bone?
It binds Ca2+
What makes up the mineral component of bone?
Hydroxyapatite is CaPO3 crystals.
What does the mineral component and osteoid confer to bone?
Mineral confers rigidity and osteoid confers tensile strength.
What are the 4 types of bone cells?
Osteoprogenitor
Osteoblasts
Osteoclasts
Osteocytes
Where would you find osteogenic cells?
In the osteogenic layer of the periosteum and in the endosteum.
What is the precursor to the osteogenic cell?
They are actually mesenchymal cells of the bone.
What enzyme do osteoblasts contain that allows them to form bone?
Alkaline phosphatase
When osteoblasts are found on the resting surface of bone, what are they called?
Bone lining cells and they have flat nuclei.
Which bone cells synthesize osteoid?
Osteoblasts
How do osteocytes communicate with one another?
Through canaliculi and gap junctions.
What hormone stimulates fast Ca2+ exchange and what is fast Ca2+ exchange?
PTH stimulates osteocytes to suck up Ca2+ from the lacunar fluid and transfer it through canaliculi to osteoblasts which dump the Ca2+ into the blood.
What 3 enzymes do osteoclasts have?
Carbonic anhydrase to generate protons from CO2.
Acid phosphatase.
Cathepsin K.
What does PTH do to osteoclasts?
It stimulates them to perform slow Ca2+ exchange which is break down of bone to yield Ca2+
What are the spaces called that osteoclasts live in?
Howship's lacunae.
Why do osteoclasts have ruffled border?
To increase surface area for bone resorption.
What 2 hormones regulate osteoclast activity?
Vitamin D and PTH
Why can't bone grow by interstitial growth?
Because osteoblasts and osteocytes can't divide.
What is another name for fast Ca2+ exchange?
Osteocytic osteolysis
Describe the basic structural unit of bone?
The haversian system (osteon) is made up of concentric lamellae which are alternating left and right hand helices.
A central blood vessel sits in the haversian canal and these are connected through Volkman's canals.
Canaliculi interconnect osteocytes around the rings.
Who produces the inner and outer circumferential lamellae?
The osteogenic layer of periosteum produces the outer circumferential lamellae and the endosteum produces the inner circumferential lamellae.
What are interstitial lamellae?
Older haversian systems that have been replaced.
Is bone vascular or avascular?
Bone is VERY vascular.
What are Sharpey's fibers?
Pieces of dense irregular CT from the fibrous periosteum which dip down into the outer circumferential lamellae.
Where are the 3 places you don't find periosteum?
Articular cartilage
Where tendons and muscles insert
On sesamoid bones
Where are the 4 places that you find blood vessels in bone?
1) Blood vessels, nerves and lympathics in the fibrous layer of periosteum.
2) Volkman's canals
3) Nutrient artery in bone marrow
4) Haversian/central canal
What are the 3 types of bone surfaces?
Forming, resting and resorbing.
Describe the 2 phases of bone formation?
Matrix formation - Osteoblasts lay down osteoid which contains osteocalcin.
Osteocalcin binds Ca2+ in the area and keeps it there.
Osteoblast secretes alkaline phosphatase which increases [Ca2+] and [PO4] in the area.
Osteoblasts secrete vesicles of Ca2+, PO4 and alkaline phosphatase which crystallizes in the matrix.
Describe intramembranous ossification?
There is no cartilage model. Mesenchymal cells develop directly into osteoblasts which start making osteoid.
The osteoid binds Ca2+ and starts to mineralize, forming the primary ossification center.
Describe endochondral bone formation?
Begin with hyaline cartilage model with perichondrium surrounding except at articulating surfaces.
Perichondrium becomes vascularized and this stimulates osteoblasts to differentiate.
This causes a periosteal collar to form around the bone diaphysis.
Periosteal bud (blood vessel) invades the middle of hyaline cartilage causing chondrocytes to die.
Osteogenic cells come in with blood and differentiate into osteoblasts which form the primary ossification center.
How does one create a marrow cavity in the bone?
Bone is added to the outer sides of the periosteal collar and cartilage is removed from inner side.
When does the secondary ossification center form?
Only after birth is the hyaline cartilage in the epiphysis replaced
During bone formation, what is the only place that hyaline cartilage will remain forever?
At the articular cartilage region.
When do the epiphyseal plates go away?
~25 yrs of age.
What are the 5 zones of the epiphyseal plates?
Zone of resting cartilage - between epiphysis and epiphyseal plate.
Zone of proliferation - chondrocytes mitosing for interstitial growth.
Zone of hypertrophy - chondrocytes get huge, deposit matrix and die.
Zone of calcification - calcification of the matrix occurs.
Zone of ossification - osteoblasts ossify the matrix.
What are the main regions we find red bone marrow?
Pelvic bones, sternum, vertebrae and skull
What is the difference between red and yellow bone marrow?
Yellow marrow is full of fat and is not hematopoietic
Describe blood flow to bone marrow?
Nutrient artery from periosteum splits into central longitudinal arteries which then split into radial arteries. The radial arteries enter Volkman's canals and then central canals.
What supports the venous sinusoids in bone marrow?
Adventitial reticular cells support the thin simple squamous endothelium
What lines the venous sinusoids in the bone marrow?
Endothelium
What type of collagen do you find lining the venous sinusoids?
Reticular fibers.
True/False Adventitial reticular cells in the bone marrow make reticular fibers
FALSE! They are for support. THE NORMAL RETICULAR CELLS MAKE THE RETICULAR FIBERS
How do blood cells leave the venous sinusoids, through or between the endothelial cells?
There are migration pores in the endothelial cells so the blood cells go right through these pores (through the cells).
What are the 4 stromal cells of the bone marrow?
Macrophages, reticular cells, fibroblasts and endothelial cells.
What is the function of the 4 stromal cells in the bone marrow?
Macrophages phagocytose RBC nuclei.
Endothelial cells and fibroblasts make growth factors.
Reticular cells make reticular fibers (NOT ADVENTITIAL RETICULAR CELLS) and store fat in some instances.
What are the relative locations of cells in the bone marrow cords?
RBC's develop in erythroblastic islets close to sinusoids.
Here macrophages can recycle the iron and phagocytose pyknotic nuclei.
Neutrophils develop further away.
Megakaryocytes have to be right next to sinusoid walls to release platelets.
Where does hematopoiesis occur between 2 weeks and 3 months of age?
In the mesoderm of the yolk sac. These are nucleated RBC's and it is the mesoblastic stage.
Where is hematopoiesis from 6 weeks to birth?
In the liver and spleen, these are still nucleated RBC's
When does hematopoiesis begin in the bone marrow?
At 6th week the primary ossification center develops and is in full swing by 5 month.
What are the 3 classes of cells in the bone marrow?
Stem cells
Progenitor cells
Precursor cells
What is PHSC?
Pleuripotential hematopoietic stem cells of bone marrow which can self-renew or give rise to MHSC (multipotential)
What is MHSC?
Multipotential hematopoietic stem cell which are either CFU-S (myeloid line) or CFU-Ly (lymphoid line)
What are examples of progenitor cells?
CFU-GM, CFU-M, CFU-E, CFU-B.
Progenitor cells are committed to a single cell lineage.
What is a precursor cell?
Cell in each lineage displaying unique characteristics.
Which precursor cell responds to erythropoietin?
CFU-E. Although so can BFU-E during severe anemia which is why it is called burst forming unit.
Why are they called primary and secondary granules?
Because the primary azurophillic granules form before the secondary specific granules.
What are criteria used to ID proerythroblast?
Huge cell
Central nucleus with nucleoli
Basophillic cytoplasm due to ribosomes
NO GRANULES
Can mitose
What criteria are used to ID basophillic erythroblast?
Very dark blue cytoplasm (RIBOSOMES MAKING HB)
Clumped chromatin and more condensed nucleus.
Can mitose
What are criteria used to ID polychromatophillic erythroblast?
CHECKERBOARD NUCLEUS
Grey cytoplasm due to accumulation of hemoglobin
LAST CELL THAT CAN DIVIDE
What is the last cell in the erythroid line that can divide?
The polychromatophillic erythroblast
What are criteria used to ID orthochromatophillic erythroblast?
Cytoplasm is same as mature erythrocyte (ortho means same).
Nucleus is eccentric dark round circle.
CANNOT DIVIDE
What are criteria used to ID reticulocytes?
No nucleus
Pink cytoplasm
Special stains pick up RNA as black fibers in cell
4 things needed to make an erythrocyte?
Hemoglobin
Glycolytic enzymes
Cytoskeleton
Plasma membrane
Why is the cytoplasm of a myeloblast slightly basophillic?
Due to RER
At what stage are the azurophillic granules first made during granulocyte maturation?
The promyelocyte stage
When are the secondary granules made during granulocyte maturation?
Myelocyte
What is the difference in colors of the secondary granules of granulocytes?
Neutrophil is iliac
Eosinophil is red-orange
Basophil is blue-purple
What is the final cell that can mitose in the granulocyte lineage?
Myelocyte
What are the characteristics of the metamyelocyte?
Eccentric, kidney-bean shaped nucleus.
Light blue cytoplasm
How much of the peripheral blood is neutrophils?
60-70%
What do neutrophil azurophillic granules contain?
Lysozyme, acid phosphatase, myeloperoxidase and defensins (antibacterial proteins)
What do neutrophil secondary granules contain?
Lactoferrin (binds iron away from bacteria)
Lysozyme
How much of the peripheral blood is eosinophils?
3% (1-4%)
What is found in eosinophil secondary granules?
Major basic protein (forms holes in parasite PM)
Histaminase (reduce inflammation)
How could you increase the levels of granulocytes in peripheral blood?
Neutrophils - bacterial infection.
Eosinophils - parasite or worm infection.
Basophils - allergic reaction.
How much of the peripheral blood is basophils?
1%
How is a basophil similar to a mast cell?
Both contain IgE receptors on their surface and when this is bound by antigen, both release histamine.
At what stage do the azurophillic granules of monocytes arise?
Promonocyte
How much of the peripheral blood is monocytes?
6% (4-10%)
What does a monocyte look like?
Largest cell in the blood with azurophillic granules and large eccentric kidney shaped nucleus.
How do megakaryoblasts divide?
By endomitotic division (64N)
What granules do megakaryocytes have?
α granules - vWF, PGDF, platelet aggregation factors
δ granules - serotonin and other platelet adhesion factors
λ granules - lysosomes for clot dissolution
Why do you need α granules in megakaryocytes?
α granules are responsible for vessel repair, platelet aggregation and coagulation of blood.
Why do you need δ granules in megakaryocytes?
They contain factors that facilitate platelet aggregation, adhesion and stimulate vasoconstriction
Why do you need λ granules in megakaryocytes?
Contain hydrolytic enzymes for clot resorption
What part of the megakaryocyte do the platelets come off of?
The platelet demarcation channels
What are the 2 parts of the platelet called?
The hyalomere which is the outer light part (microtubules) and the granulomere which is the part containing the 3 types of granules.
What is the difference between serum and plasma?
Serum is plasma without the coagulation proteins
Name 3 common anticoagulants?
Heparin
Citrate
EDTA
The latter 2 are Ca2+ chelators
When does DNA recombination occur in the B cell?
Before birth in the germline cells.
What is clonal selection?
When an antigen binds a specific B cell and stimulates it to tweak it's DNA to bind that antigen specifically
Why do we need Vit. K for coagulation protein synthesis?
The enzyme γ-glutamyl carboxylase needs Vit. K as a cofactor in order to γ carboxylate factors II, VII, IX and X.
Why do you need γ-carboxylation of the coagulation factors?
In order for them to interact with Ca2+. Ca2+ binds the negative phospholipids on the endothelial surface (and platelet surface) to the negative γ-carboxyglutamic acid residues on the coagulation factors.
This allows them to interact with each other.
Where in the coagulation protein are the glu residues that we γ-carboxylate?
They are on the N-terminus and the carboxylation process forms γ-carboxyglutamic acid residues (Gla)
How do you start the intrinsic clotting cascade?
HMW kininogen, prekallikrein and factor XII all work together to activate XII to XIIa
What is the embryonic origin of blood?
Mesoderm derived because it is CT without fibers (until clotting occurs)
Where are tPA, Antithrombin III, heparin and thrombomodulin made?
Made and released by the endothelium
Where are protein C and protein S made?
With all the other factors in the liver (except factor III)
Are protein C and protein S anticoagulants or coagulants?
They are anticoagulants because they degrade factor V and factor VIII
How do you activate protein C and protein S?
Once thrombin is formed during coagulation, it stimulates protein C. With the help of thrombomodulin released from the endothelium, protein C is activated 1000 fold. Activated protein C degrades factor V/VIII but also requires protein S as a cofactor to do this.
What is pre-prothrombin?
It is prothrombin before γ-carboxylation by γ-glutamyl carboxylase.
How do warfarin and coumadin work?
They block epoxide reductase which prevents the conversion of Vit. K epoxide back into the active form of Vit. K.
Why do you need epoxide reductase?
γ-glutamyl carboxylase requires Vit. K to carboxylate pre-prothrombin. When this happens, Vit. K is converted into Vit. K epoxide (an inactive form). Epoxide reductase converts Vit. K epoxide back into Vit. K.
What is an inhibitor of plasmin?
α2-antiplasmin is an antagonist of plasmin to ensure that the clot isn't broken up too fast.
What is the difference between the stochastic and deterministic theories?
Stochastic means that progenitor cells randomly decide to form differentiated cells or self renew.
Deterministic means that cytokines and growth factors stimulate the process.
What is meant by self-renewal?
Stem cells can divide to make more of themselves (cells with exactly the same differentiation state)
What is meant by asymmetric mitosis?
One daughter cell differentiates, the other self renews.
What is trade-off of differentiation?
Cells mature to become more specialized but lose the ability to divide.
What are the 4 types of growth factors?
1) Colony stimulating factors (GM-CSF, G-CSF, M-CSF, IL-3)
2) Erythropoietin - for RBC's
3) Thrombopoietin - for megakaryocytes.
4) IL-5 and IL-6 - for eosinophillic lineage and lymphoid cells.
What are the clinical equivalents of Epo, G-CSF and GM-CSF?
Procrit, Epoietin α
Neupogen, Filgrastim
Leukine, Sargramostim
What is the difference between acute and chronic leukemia?
Acute is a lot of blast cells in the peripheral blood.
Chronic is a lot of normal cells and few blast cells.
What is the lifespan of an RBC?
100-120 days
What is the lifespan of a neutrophil?
7 hours in the circulation, 4 days in CT
What is the lifespan of a platelet?
10 days
What are the 3 things that bone marrow stromal cells produce?
V-CAMS and integrins
Collagen, fibronectin and laminin
Growth factors.
What are considered early stage growth factors?
They help the cell move from Go into G1 (IL-6, IL-11, IL-12).
OR they keep the cell cycling (GM-CSF, IL-3, IL-4)
What are considered late stage growth factors?
Maturation factors like Epo, Tpo, G-CSF, GM-CSF and M-CSF.
What is another name for IL-3?
Multi-CSF because it stimulates all the cells except RBCs
What cells does GM-CSF stimulate?
Neutrophils, eosinophils and macrophages
What growth factor is needed for Eosinophil proliferation?
IL-5
What growth factor is needed for basophil or T-lymphocyte proliferation?
IL-6
What are glycophorins?
Membrane bound proteins with carb side chains, N-acetylneuraminic acid and sialic acid
What is band-3?
A bicarb exchanger found in the RBC membrane
What is the Embden Myerhof pathway and what is it good for?
It is a side pathway off glycolysis which produces 2,3-DPG during hypoxia
What is the iron storage protein in most cells?
Ferritin
When do you get megaloblastic or macrocytic anemia?
When the cell has a hard time synthesizing DNA such as B12 or folate deficiency (pernicious anemia)
When do you get microcytic anemia?
When the ability to synthesize hemoglobin is deficient. W/o Hb, cells continue to divide continuously and get tiny.
This happens with iron deficiency, thalassemias, heavy metal poisoning and anemiochronic disease.
Which cells make GIF?
The parietal cells along with HCl.
What does GIF do?
It binds with B12 in the duodenum preventing proteolytic degradation.
Where is B12 absorbed?
In the terminal ileum with GIF attached by the intrinsic factor-B12 receptor.
What carries B12 to the liver?
Transcobalamin
What are the 4 causes of microcytic hypochromic anemias?
1) Iron deficiency
2) Thalassemia
3) Chronic diseases (anemiochronic diseases)
4) Porphyrin and heme synthesis defects (lead poisoning and sideroblastic anemias)
What is sideroblastic anemia?
When you are unable to form heme so iron deposits in the mitochondria forming cells caused ringed sideroblasts.
What causes macrocytic anemias?
Any defect in DNA synthesis of the RBC. Most common one is B12 or folate deficiency.
List 3 causes of normocytic normochromic anemias?
Acute blood loss
Hemolysis
Bone marrow failure
Definition of polycythemia?
Increase in RBCs, [hemoglobin] and hct
What is the difference between absolute and relative polycythemia?
Absolute is an increase in the number of RBCs
Relative is a decrease in plasma volume thereby leading to polycythemia
Why are people with sickle cell predisposed to infection?
Because the macrophages in the spleen are overworked destroying RBCs. This leads to auto-infarction of the spleen and predisposition to infection.
What is the treatment for sickle cell?
Hydroxyurea or 5-Azacytidine
What is the equation for MCV and what does it tell you?
Mean corpuscular volume (MCV) = hct/RBC count.
MCV tells you the relative size of the RBC (microcytic or macrocytic)
What is the equation for MCH and what does it tell you?
Mean corpuscular hemoglobin (MCH) = [hb]/RBC count and doesn't actually tell you much. MCHC is better test.
What are normal levels for MCV?
90fL
What is the equation for MCHC and what does it tell you?
Mean corpuscular hemoglobin concentration (MCHC) = [hb]/hct and it tells you the hemoglobin concentration.
This is useful for hypochromic anemias
What are the normal levels for MCHC?
30g/dl
Are most people + or - blood?
85% of people are Rh+ blood
Why do you use UV light on newborns with jaundice?
To convert unconjugated (insoluble) bilirubin into lumirubin which is soluble and can be excreted.
What is the difference between slow and fast HCO3- exchange?
Slow bicarb exchange is converting CO2 into HCO3- in the plasma.
Fast bicarb exchange is using carbonic anhydrase in the RBC to convert it.
What are the relative numbers of WBC's in the peripheral blood?
Neutrophils 60%
Lymphocytes 30%
Monocytes 6%
Eosinophils 3%
Basophils 1%
If I find a granule with lactoferrin, B12 binding protein, lysozyme and complement receptors in it, where am I?
You are in a neutrophil secondary (specific) granule.
If I find a granule with histamine, heparin and serotonin in it, where am I?
You are in a basophil secondary (specific) granule
If I find a granule containing major basic protein, what else will I find in the granule and where am I?
You will find eosinophil peroxidase and you are in an eosinophil secondary (specific) granule
What are the 7 steps of phagocytosis?
1)Adhesion (selectins make granulocyte roll, integrins make them stick and diapedese)
2) Chemotaxis (mast cell released chemotactic agents attract neutrophils)
3) Recognition (bacteria coated with opsonins IgG, IgM, C3 and C3a)
4) Phagocytosis
5) Degranulation (secondary granules fuse with phagosome first, then primary granules)
6) Generation of ROS (O2 respiratory burst)
7) Neutralize spare superoxide (using SOD and catalase)
What are the steps of the O2 respiratory burst?
1) NADPH oxidase uses NADPH to generate superoxide from O2.
2) Superoxide dismutase creates H2O2 from superoxide.
3) Myeloperoxidase adds Cl- to H2O2 and form HOCl (hypochlorite) which destroys bacteria.
4) Glutathione regenerates NADPH for first reaction.
What are the 2 steps to innate defense?
1) Neutrophils show up at pathogen site, phagocytose with O2 burst, release chemoattractants and die. Dead neutrophils, bacteria and myeloperoxidase form green pus.
2) Macrophages show up, also phagocytose and do O2 resp. burst. Also release cytokines (TNF α, IL-1 and IL-12) and eicosanoids (LTB4) which are chemoattractants. Finally, present degraded pathogen antigens on MHC-II surface receptors.
What are the 2 steps to immune defense?
Comes after the innate defense.
3) Macrophages that have destroyed bacteria are presenting antigen on their MHC-II molecules (acting as APCs) in the lymph nodes. Killer T-cells (CD-8+) recognize the MHC-II and destroy the whole macrophage with perforins. They also release more cytokines to recruit B cells. Killer T-cells also recognize MHC-I presented on any non-self cell.
4) B-cells come in contact with pathogen and pump out antibodies.
What is leukocytosis and what causes it?
> 12,000 cells/mm3
Bacterial infection, inflammation, necrosis, metabolic toxins, hemorrhage, splenectomy and stress.
What are the 4 stages of infection?
Early infection: Neutrophils diapedese out and leukocyte count drops. Bone marrow reserves drop.
Established infection: Bone marrow ups production to re-establish reserves and increase blood levels.
Recovery: Marrow production decreases and blood levels return to normal
OR Exhaustion: Neutropenia during course of infection, poor sign.
What is leukopenia and what causes it?
Leukocytes < 4000
Causes: Page 505
What chemoattractant released from bacteria attracts neutrophils?
F-met-leu-phe
What host cell chemoattractants attract neutrophils?
C5a, LTB4, PAF and IL-8
What would you use the nitroblue tetraxolium test for?
The NBT test turns from blue to black in the presence of superoxide.
It is used to test for NADPH oxidase deficiency (chronic granulomatous disease)
What is chronic granulomatous disease?
Defect in the NADPH oxidase enzyme preventing the formation of superoxide. Defective respiratory burst reaction.
Which kills bacteria and which kills virally infected cells?
Neutrophils take out bacteria and NK (T) cells take our virally infected cells.
Where do you find multipolar neurons?
Bipolar?
Unipolar?
Motor neurons of ventral horn and autonomic ganglia
Retina, vestibular, cochlea ganglia and olfactory epithelium.
DRG
Germ layer of origin
Schwann cells, satellite cells, DRG, postganglionic cells?
Neural crest
Which parts of the neuron are not myelinated?
The dendrites and axon hillock
What is neuronal fast transport?
Dyneins moving vesicles retrograde, Kinesins moving vesicles and organelles anterograde.
What are the 7 layers of the myelinated neuron?
Axoplasm, axolemma, periaxonal space, myelin sheath, schwann sheath (neurilemma), external lamina and endoneurium.
Who am I? Surrounded by external lamina, derived from neural crest and contains GFAP?
Schwann cells
If I see protein zero, where am I?
Po is found in the intraperiod lines of the peripheral myelin sheath. The intraperiod lines are E surfaces together.
If I see myelin basic protein, where am I?
You are in the major dense lines of a peripheral myelin sheath which is the P surfaces glued together.
If I want to bind a neurotransmitter to a microfilament, what do I need? What about binding it for release or binding it to the active zone?
Synapsin
Synaptophysin binds it to the active zone and synaptotagmin allows release.
What does CaM kinase do?
It is activated by Ca rushing into the synaptic bouton and it phosphorylates both synapsin and synaptophysin allow nt to dock with synaptotagmin.
What is neurokeratin network?
It is MBP and Po artifact, NOT NEUROFILAMENTS
What type of neuron conveys acute pain, touch, pressure and motor efferents?
Type A - GSA and GSE
What type of neuron conveys visceral afferents and preganglionics?
Type B - GVA and pre GVE
What type of neuron conveys chronic pain and postganglionics?
Type C - GSA and post GVE
Classify the tissue?
Endoneurium
Perineurium
Epineurium
Endoneurium - Loose CT with reticular fibers and capillaries.
Perineurium - DICT with perineurial cells (tight junctions and basal lamina).
Epineurium - DICT
What are the 2 types of free nerve endings and where are they? What makes them free?
Merkel cells located in the dermis, response to touch
Peritrichial hair cells which wrap around hair follicle.
They are free because they have no myelin, no CT and no Schwann cells
What are the 4 encapsulated nerve endings to know?
Meissner's corpuscle (touch)
Pacinian corpuscle (pressure)
Muscle spindles
Golgi Tendon Organs
All neurons of the DRG release .....?
Glutamate
Grey matter, vascular or avascular? What about white matter?
Very vascular
Avascular
Classify the tissue? DURA
Outer layer is dense irregular CT. It is tight on bone so is basically periosteum. The inner layer is fibrous tissue forming the reflections.
Germ layer of origin?
Dura, arachnoid and pia
Dura is mesoderm
Arachnoid and pia are neural crest.
Which are vascular vs. avascular?
Arachnoid avascular
Pia vascular
What is the difference between fibrous astrocyte and protoplasmic astrocyte?
Fibrous astrocyte - found in white matter
Protoplasmic astrocyte - In grey matter and have the feet.
Which 2 cells have GFAP?
Schwann cells and astrocytes
Grey matter, vascular or avascular? What about white matter?
Very vascular
Avascular
Grey matter, vascular or avascular? What about white matter?
Very vascular
Avascular
Germ layer of origin? Microglia
Microglia are derived from monocytes which are from mesoderm
What are the internal and external glial limiting membranes?
Internal glial limiting membrane is astrocytic feet against base of ependymal cells. External is astrocytic feet against pia.
Classify the tissue? DURA
Outer layer is dense irregular CT. It is tight on bone so is basically periosteum. The inner layer is fibrous tissue forming the reflections.
Classify the tissue? DURA
Outer layer is dense irregular CT. It is tight on bone so is basically periosteum. The inner layer is fibrous tissue forming the reflections.
Germ layer of origin?
Dura, arachnoid and pia
Dura is mesoderm
Arachnoid and pia are neural crest.
What surface specializations do ependymocytes have?
Striated border microvilli with cilia.
Attached to each other by tight junctions
Germ layer of origin?
Dura, arachnoid and pia
Dura is mesoderm
Arachnoid and pia are neural crest.
Which are vascular vs. avascular?
Arachnoid avascular
Pia vascular
What is the difference between fibrous astrocyte and protoplasmic astrocyte?
Fibrous astrocyte - found in white matter
Protoplasmic astrocyte - In grey matter and have the feet.
Which are vascular vs. avascular?
Arachnoid avascular
Pia vascular
What are 3 locations of fenestrated capillaries?
Glomerulus
Choroidal cells
Choriocapillaris
Which 2 cells have GFAP?
Schwann cells and astrocytes
What is the difference between fibrous astrocyte and protoplasmic astrocyte?
Fibrous astrocyte - found in white matter
Protoplasmic astrocyte - In grey matter and have the feet.
What forms the BBB and what is weird about this?
Tight junctions between capillary endothelial cells. This is weird because endothelial cells usually have fascia occludens.
Germ layer of origin? Microglia
Microglia are derived from monocytes which are from mesoderm
What are 6 differences between CNS and PNS myelin?
1) CNS myelin has an external lamina surrounding.
2) Axons are so close they share intraperiod lines.
3) Oligo's myelinate multiple neurons.
4) No endoneurium
5) No neurilemma (most important)
6) Proteolipid protein (PLP) is found in intraperiod line instead of Po.
Which 2 cells have GFAP?
Schwann cells and astrocytes
What are the internal and external glial limiting membranes?
Internal glial limiting membrane is astrocytic feet against base of ependymal cells. External is astrocytic feet against pia.
Germ layer of origin? Microglia
Microglia are derived from monocytes which are from mesoderm
What surface specializations do ependymocytes have?
Striated border microvilli with cilia.
Attached to each other by tight junctions
What is the only exception you should know for sympathetic innervation?
Nepi to everywhere except sweat glands of body. Remember: sweat glands of hands and feet are Nepi
What are the internal and external glial limiting membranes?
Internal glial limiting membrane is astrocytic feet against base of ependymal cells. External is astrocytic feet against pia.
What are 3 locations of fenestrated capillaries?
Glomerulus
Choroidal cells
Choriocapillaris
What surface specializations do ependymocytes have?
Striated border microvilli with cilia.
Attached to each other by tight junctions
4 locations of nicotinic receptors and blocking drug?
Found in PS and S post cell bodies, sk.muscle end plate and adrenal medulla.
Blocked by hexamethonium (not at NMJ)
What are 3 locations of fenestrated capillaries?
Glomerulus
Choroidal cells
Choriocapillaris
2 locations for muscarinic receptors and blocking drug?
All PS end organs and sweat glands of body for S.
Blocked by atropine.
What forms the BBB and what is weird about this?
Tight junctions between capillary endothelial cells. This is weird because endothelial cells usually have fascia occludens.
What are 6 differences between CNS and PNS myelin?
1) CNS myelin has an external lamina surrounding.
2) Axons are so close they share intraperiod lines.
3) Oligo's myelinate multiple neurons.
4) No endoneurium
5) No neurilemma (most important)
6) Proteolipid protein (PLP) is found in intraperiod line instead of Po.
What forms the BBB and what is weird about this?
Tight junctions between capillary endothelial cells. This is weird because endothelial cells usually have fascia occludens.
What is the only exception you should know for sympathetic innervation?
Nepi to everywhere except sweat glands of body. Remember: sweat glands of hands and feet are Nepi
Grey matter, vascular or avascular? What about white matter?
Very vascular
Avascular
Grey matter, vascular or avascular? What about white matter?
Very vascular
Avascular
4 locations of nicotinic receptors and blocking drug?
Found in PS and S post cell bodies, sk.muscle end plate and adrenal medulla.
Blocked by hexamethonium (not at NMJ)
2 locations for muscarinic receptors and blocking drug?
All PS end organs and sweat glands of body for S.
Blocked by atropine.
Classify the tissue? DURA
Outer layer is dense irregular CT. It is tight on bone so is basically periosteum. The inner layer is fibrous tissue forming the reflections.
Classify the tissue? DURA
Outer layer is dense irregular CT. It is tight on bone so is basically periosteum. The inner layer is fibrous tissue forming the reflections.
What are 6 differences between CNS and PNS myelin?
1) CNS myelin has an external lamina surrounding.
2) Axons are so close they share intraperiod lines.
3) Oligo's myelinate multiple neurons.
4) No endoneurium
5) No neurilemma (most important)
6) Proteolipid protein (PLP) is found in intraperiod line instead of Po.
Germ layer of origin?
Dura, arachnoid and pia
Dura is mesoderm
Arachnoid and pia are neural crest.
Germ layer of origin?
Dura, arachnoid and pia
Dura is mesoderm
Arachnoid and pia are neural crest.
Which are vascular vs. avascular? Arachnoid and Pia
Arachnoid avascular
Pia vascular
Which are vascular vs. avascular?
Arachnoid avascular
Pia vascular
What is the only exception you should know for sympathetic innervation?
Nepi to everywhere except sweat glands of body. Remember: sweat glands of hands and feet are Nepi
What is the difference between fibrous astrocyte and protoplasmic astrocyte?
Fibrous astrocyte - found in white matter
Protoplasmic astrocyte - In grey matter and have the feet.
4 locations of nicotinic receptors and blocking drug?
Found in PS and S post cell bodies, sk.muscle end plate and adrenal medulla.
Blocked by hexamethonium (not at NMJ)
Which 2 cells have GFAP?
Schwann cells and astrocytes
2 locations for muscarinic receptors and blocking drug?
All PS end organs and sweat glands of body for S.
Blocked by atropine.
Germ layer of origin? Microglia
Microglia are derived from monocytes which are from mesoderm
What is the difference between fibrous astrocyte and protoplasmic astrocyte?
Fibrous astrocyte - found in white matter
Protoplasmic astrocyte - In grey matter and have the feet.
What are the internal and external glial limiting membranes?
Internal glial limiting membrane is astrocytic feet against base of ependymal cells. External is astrocytic feet against pia.
What surface specializations do ependymocytes have?
Striated border microvilli with cilia.
Attached to each other by tight junctions
Which 2 cells have GFAP?
Schwann cells and astrocytes
Germ layer of origin? Microglia
Microglia are derived from monocytes which are from mesoderm
What are 3 locations of fenestrated capillaries?
Glomerulus
Choroidal cells
Choriocapillaris
What are the internal and external glial limiting membranes?
Internal glial limiting membrane is astrocytic feet against base of ependymal cells. External is astrocytic feet against pia.
What forms the BBB and what is weird about this?
Tight junctions between capillary endothelial cells. This is weird because endothelial cells usually have fascia occludens.
What surface specializations do ependymocytes have?
Striated border microvilli with cilia.
Attached to each other by tight junctions
What are 3 locations of fenestrated capillaries?
Glomerulus
Choroidal cells
Choriocapillaris
What are 6 differences between CNS and PNS myelin?
1) CNS myelin has an external lamina surrounding.
2) Axons are so close they share intraperiod lines.
3) Oligo's myelinate multiple neurons.
4) No endoneurium
5) No neurilemma (most important)
6) Proteolipid protein (PLP) is found in intraperiod line instead of Po.
What is the only exception you should know for sympathetic innervation?
Nepi to everywhere except sweat glands of body. Remember: sweat glands of hands and feet are Nepi
What forms the BBB and what is weird about this?
Tight junctions between capillary endothelial cells. This is weird because endothelial cells usually have fascia occludens.
4 locations of nicotinic receptors and blocking drug?
Found in PS and S post cell bodies, sk.muscle end plate and adrenal medulla.
Blocked by hexamethonium (not at NMJ)
What are 6 differences between CNS and PNS myelin?
1) CNS myelin has an external lamina surrounding.
2) Axons are so close they share intraperiod lines.
3) Oligo's myelinate multiple neurons.
4) No endoneurium
5) No neurilemma (most important)
6) Proteolipid protein (PLP) is found in intraperiod line instead of Po.
2 locations for muscarinic receptors and blocking drug?
All PS end organs and sweat glands of body for S.
Blocked by atropine.
What is the only exception you should know for sympathetic innervation?
Nepi to everywhere except sweat glands of body. Remember: sweat glands of hands and feet are Nepi
4 locations of nicotinic receptors and blocking drug?
Found in PS and S post cell bodies, sk.muscle end plate and adrenal medulla.
Blocked by hexamethonium (not at NMJ)
2 locations for muscarinic receptors and blocking drug?
All PS end organs and sweat glands of body for S.
Blocked by atropine.
Mechanism of M2 muscarinic receptor?
Gi which inhibits adenylate cyclase in heart causing hyperpolarization and decrease HR.
Mechanism of smooth muscle muscarinic receptor?
Gq which increases IP3 through PLC and thereby increases Ca2+
Which adrenergic receptors are usually excitatory?
alpha 1 and beta 1
Which adrenergic receptors are usually inhibitory?
alpha 2 and beta 2
What is the purpose of beta 3's in brown adipose?
Thermogenesis
Nepi is stronger on ..... whereas Epi is stronger on .....?
alpha's
beta's
Locations of alpha 1 receptors?
Most blood vessels
Radial muscle of eye
Stomach and bladder sphincters
Salivary glands
Sweat glands on palms and soles.
Locations of alpha 2 receptors?
Pancreatic beta cells
Pancreatic acinar cells
Blood platelets
Presynaptic membrane
Locations of beta 1 receptors?
Cardiac muscle cells
JG cells of kidney
Posterior pituitary
Adipocytes
Locations of beta 2 receptors?
Airways.
Coronary, sk.muscle, adipose tissue and liver blood vessels.
Ciliary muscle of eye.
Hepatocytes of liver.
2 agonists and 3 antagonists of alpha 1 receptors?
Agonists: Nepi and phenylephrine
Antagonists: Phenoxybenzamine, phentolamine, prazosin
Alpha 2 agonist and antagonist?
Clonidine
Yohimbine
3 B1 agonists and 2 B1 antagonists?
Agonists: Nepi, Isoproterenol, Dobutamine.
Antagonists: Propranolol and metoprolol
2 B2 agonists and 2 antagonists?
Agonist: Isoproterenol, Albuterol
Antagonist: Butoxamine, Propranolol
1 nicotinic agonist and 2 antagonists?
Agonist: Carbachol
Antagonist: Curare, Hexamethonium
1 muscarinic agonist and 1 muscarinic antagonist?
Agonist: Carbachol
Antagonist: Atropine
What do the vesicles look like for Ach, Nepi, Neuropeptide Y and VIP?
Ach: small clear vesicles
Nepi: small dense vesicles
Neuropeptide Y and VIP: Large dense core vesicles.
What is the mechanism of guanylate cyclase receptors?
Conversion of GTP into cGMP which activates protein kinase G (cGMP dependent protein kinase)
What is the job of protein kinase G?
1) It phosphorylates K channels activating them, allowing hyperpolarization of the smooth muscle cell.
2) It prevents Ca2+ channels from opening.
3) It inhibits IP3 activated Ca2+ channels.
4) It activates myosin light chain phosphatase by phosphorylating it.
What is the main compound that binds to the soluble guanylate cyclase receptor?
Nitric oxide
How do you make nitric oxide?
Certain cells use nitric oxide synthase and convert Arg into Citrulline and NO.
Mechanism of nitroglycerin?
Reacts with tissue thiols to generate s-nitrosothiols which liberate NO.
Mechanism for pain induced during inflammation?
Inflammation causes release of bradykinin, prostaglandins, serotonin and substance P.
Prostaglandins in particular bind to 7-transmembrane G-protein coupled receptor. This causes phosphorylation of a Na channel in the DRG resulting in activation.
In the CNS, the prostaglandins cause phosphorylation of non-selective cation channels and inhibit glycinergic activity.
What enzymes are required to make prostaglandins?
Phospholipase A2 creates arachidonic acid from DAG. The arachidonic acid is converted into PGH2 by COX enzymes.
What drugs block the production of prostaglandins?
Corticosteroids and cortisol block PLA2.
NSAIDS block Cox.
Aspirin is an irreversible blocker of COX1/COX2
Ibuprofen is a reversible blocker of both.
Vioxx is a selective COX2 blocker.
Why is aspirin an irreversible blocker of COX enzymes?
Because it adds a serine group to the enzyme.
With drugs, what does Kd and Bmax tell you?
Kd is the [] of drug required to bind half the receptors
Bmax is the total number of receptors.
How are epilepsy and hemorrhage induced seizures associated with potassium?
Epilepsy is attributed to inability to control ECF K.
Serum K is 1.6X higher than CSF K so bleeding also causes hyperkalemia.
Which ion controls duration of AP?
The K channel
Ethyl alcohol blocks .....?
Na/K channels
List 3 drugs that block K channels?
TEA, 4-amino-pyridine and dendrotoxin
Mechanism of phenytoin to help epilepsy?
Phenytoin is a Na channel blocker used to prevent overexcitability.
How does halothane work?
It opens special K channels to hyperpolarize neurons.
How does EMG work?
Place electrodes over muscle and tell patient to move. Measure electrical activity in the muscle.
What is somatosensory evoked potentials?
Stimulating a peripheral nerve and measuring the activity in the cortex.
What is an EEG?
Electroencephalogram which is constant measurements of overall brain activity during sleep or coma.
What is event-related potentials?
Asking a patient to perform a task while you measure activity in the cortex.
Classify tissue? Conjunctiva
Stratified columnar with goblet cells
What are Meibomian glands?
Modified sebaceous glands in eyelid
What are glands of Zeiss?
Modified sebaceous glands in eyelid
What are glands of Moll?
Apocrine sweat glands in the eyelid
What is the flow of tears?
Begins in lacrimal gland then to lacrimal duct and medially across eye to lacrimal puncta. The puncta drain into the lacrimal sac which drains through the nasolacrimal duct into the inferior meatus of the nose.
Classify tissue? Sclera
Are there blood vessels here?
DICT with Type I collagen
AVASCULAR, the blood vessels seen here are in the conjunctiva
Is the cornea vascular or avascular?
It is avascular but does contain nerves.
What structure would be found at the scleral limbus?
Spaces of Fontana which drain aqueous humor into the canal of Schlemm
What are the 5 layers of the cornea and what tissue is each?
1) Anterior epithelium - stratified squamous non-keratinized.
2) Bowman's membrane - basal lamina of anterior epithelium.
3) Substantia propria - DICT with type I collagen fibers
4) Descemet's membrane - Thick basement membrane of posterior epithelium
5) Posterior epithelium - simple squamous with tight junctions.
What layer of the cornea are the nerve endings located in?
The anterior epithelium
What keeps the cornea dehydrated?
Na/K pumps in the posterior epithelium and tight junctions as well.
What is the choroid?
Highly vascular pigmented layer of loose CT and melanocytes
What type of capillaries are found in the choroid?
Choriocapillaries which are fenestrated capillaries.
What is Bruch's membrane?
Basal lamina of choriocapillaries
Type III collagen
Elastic fibers
Type III collagen
Basal lamina of pigmented cells of retina.
What is the ciliary body? What is it's make-up?
It is an extension of the choroid.
It is a 2 layered epithelium with the inner layer being non-pigmented and the outer layer being pigmented
What does the inner layer of the ciliary body do?
It is non-pigmented and it secretes aqueous humor
What forms the blood-aqueous barrier?
Tight junctions of the inner epithelial layer of the ciliary body.
Suspensory ligaments of the lens are composed of ....?
Fibrillin
What is the iris made of?
It is a continuation of the choroid. It is loose CT with NO ANTERIOR EPITHELIUM. The posterior epithelium is a double pigmented layer of cells continuing on from the ciliary body.
How do sympathetics change the pupil?
Activate the a1 receptor on the myoepithelial cells of the dilator pupillae thereby opening up the pupil
How do parasympathetics change the pupil?
Activate the muscarinic receptor on the muscle which encircles the pupil
What is the lens composition?
An avascular epithelium with no CT. (good for transplant)
What proteins are found in the lens?
Crystallins which increase refractive power
What is the main component of vitreous body? Can you replace the body? Vascular or avascular?
Hyaluronic acid
No, you are born with vitreous
It is avascular
Only .... are found in the fovea centralis?
Cones
What forms the blood retina barrier?
The tight junctions btw the pigment epithelium of the retina
Where would you find melanin granules during the day in the pigment epithelium?
In the apical microvilli
3 functions of pigment epithelium of retina?
Phagocytose shed tips of rods and cones.
Synthesize melanin.
Esterify Vit. A and transport it to rods and cones.
What are the 2 parts of the photoreceptor?
There is an inner segment where the rhodopsin is made and an outer segment that contains the membranous disks.
In short, how does the photoreceptor work?
Activated opsin transfers GTP to G-protein transducin which activates cGMP phosphodiesterase. Decreases in cGMP closes Na channels which hyperpolarizes the cell.
What is the 3rd layer of the retina and what does it represent?
It is the outer limiting membrane which is tight junctions between Muller cells and photoreceptors
What is the 4th layer of the retina and what does it represent?
The outer nuclear layer is the nuclei of the rods and cones.
What is the 5th layer of the retina and what does it represent?
It is the outer plexiform layer which is synapses between photoreceptors and bipolar cells.
What is the 6th layer of the retina and what does it represent?
Inner nuclear layer which is nuclei of bipolar cells, horizontal cells, Muller cells and amacrine cells.
What is the 7th layer of the retina and what does it represent?
Inner plexiform layer which is synapses between bipolar cells and ganglion cells.
What is the 8th layer of the retina and what does it represent?
Ganglion cell layer and it is what it says. You do not find this layer in the fovea.
What is the 9th layer of the retina and what does it represent?
Optic nerve fiber layer which is unmyelinated fibers of ganglion cells.
What is the 10th layer of the retina and what does it represent?
Inner limiting membrane and it is basement membrane of the Muller cells
What is the difference between ECF and perilymph?
They are the same except perilymph has no protein
What connects the utricle and the saccule?
The endolymphatic duct which drains into the endolymphatic sac in the cranial cavity
What surface specializations do neuroepithelial cells have?
A kinocilium which is a modified cilium and stereocilia which are microvilli.
What does the macula look like and what is it's function?
The macula are found in the utricle and saccule and have an otolithic membrane with otoliths on top.
The function is static equilibrium and linear acceleration.
Bending the stereocilia towards the kinocilium does what?
Depolarizes the neuroepithelial cells. Bending away hyperpolarizes them.
Where are the cupula located and what is their function?
In the ampulla of the semicircular ducts.
Function: Rotational (dynamic) motion and angular acceleration.
What neurotransmitter do neuroepithelial cells release?
Glutamate
What connects the cochlear duct to the saccule?
The ductus reuniens
What is special about the stria vascularis?
It is a pseudostratified epithelium that is VASCULAR. This is abnormal and this is the site of endolymph production.
What are the spiral ligament and spiral limbus?
Ligament is compact bone opposite tectorial membrane. Limbus is screw shelf on same side.
What is the difference btw the hair cells of the cochlea and the neuroepithelial cells of the macula and cupula?
The hair cells of the cochlea do not have a kinocilium, just have a taller stereocilium.
Mechanism of the hair cells?
Bending stereocilia towards the taller one, leads to opening of K channels and influx of K from the high endolymph [K]. This causes depolarization which leads to the release of glutamate which activates the axon of the bipolar cells.
What is the reticular membrane?
It is tight junctions btw the phalangeal processes of the outer phalangeal cells and the apex of the outer hair cells.
Where are low and high freq sounds heard respectively?
Low freq heard at apex, high freq heard at base
What cells make myofibrils?
The myotubes which developed from fusion of myoblasts.
What is a triad, what is it characteristic of and what protein can be found there?
It is the dilation of 2 SR's on either side of the T-tubule.
It is characteristic of sk. muscle and calsequestrin is found in the dilated ends.
What makes up the Z lines?
α-actinin which binds thin filaments to Z line with help of nebulin.
What are the 2 capping proteins of the sarcomere?
Cap Z caps the plus end of actin in the Z disc.
Tropomodulin caps the negative end at the A-I junction.
What is found at the M line?
Myomesin
Can skeletal muscle divide?
No, only hypertrophy. Satellite cells can divide and add to the muscle fibers but cannot synthesize more myofibrils.
What are the biconal areas around the cardiac muscle nucleus?
They are the organelles.
What is the ultrastructure of the intercalated disc?
Fascia adherens and desmosome at the perpendicular portions. The tonofilaments that insert into the desmosome are desmin and vimentin.
Gap junctions at the parallel portions.
3 functions of ANP?
Excrete Na and H2O
Prevent renin release
Decrease BP
What is the only CT in the heart?
Endomysium with capillaries
What is phospholamban?
It is a protein that controls the SR Ca pump in cardiac muscle. Thyroid hormone can change phospholamban activity.
Can cardiac muscle divide?
NO, only hypertrophy and scar tissue after damage.
What are the locations of multiunit smooth muscle?
Vas deferens, arrector pili, iris muscles, large arteries and lung airways.
All muscle cells are surrounded by ....?
External lamina and type III collagen (reticular fibers)
What is unique about smooth muscle?
No troponin
No T-tubules (caveolae)
SR doesn't store Ca2+
Z-discs are actually round and form dense bodies.
Ca-Calmodulin needed for contraction.
Thick filaments regulate the contraction by being phosphorylated.
What are the 4 ways to initiate smooth muscle contraction?
Nerve impulses in vascular smooth muscle.
Stretching in visceral smooth muscle.
Oxytocin in uterine smooth muscle.
Epinephrine in other places.
What is a myofibroblast?
A fibroblast that can contract and is prominent during wound healing.
What accounts for the slower repol in sk. muscle?
1) The kinetics of the delayed rectifier K channel are slower
2) T-tubules trap ECF K which prevents outward flux of K.
Mechanism of EC coupling?
SR is connected to T-tubules by a link between calcium release channels and dihydropyridine receptor.
Depolarize the T-tubule and the conformation of the dihydropyridine receptor changes opening the CRC.
How does cardiac muscle relax? How does digitalis affect this?
You have to get rid of all Ca2+. Use Na/Ca exchanger (predominant) and Ca pump.
Digitalis blocks the Na/K pump which leaves Na high in cell thereby inhibiting Na/Ca exchanger.
In blood vessel walls, if the nucleus runs parallel to blood flow what cell is it? What about perpendicular?
Endothelial nuclei run with blood flow. Smooth muscle nuclei are perpendicular.
What do Weibel palade bodies contain? What else do endothelial cells release?
vWF
They secrete basal lamina and endothelin 1 which is a vasoconstrictor
Where does the elastic lamina of blood vessels come from and how is it different?
It is secreted by endothelial cells and it is arranged as a sheet not as fibers.
All blood vessels have ..... except capillaries and PCVs?
Smooth muscle walls
Sympathetic innervation
The roots of the great vessels have .... in their tunica media?
cardiac muscle
What do fibroblasts do in the tunica adventitia?
Make type I and type III collagen as well as elastin. However, the elastin here is in fibers not sheets.
What GAGs do you find in arteries? What about veins?
Chondroitin sulfate
Dermatan sulfate
What is the composition of the tunica intima and how is it different in heart and capillaries?
It is an endothelium with subendothelial layer.
In the heart, it is endocardium and in capillaries it is just endothelium.
It has an internal elastic lamina which is type I, type III and elastin.
The heart's tunica media is called the ?
Myocardium
Which layer is thicker in arteries vs. veins?
Tunica media is thicker in arteries, tunica adventitia is thicker in veins.
The heart's adventitia is called the ....?
Epicardium and really isn't an adventitia but a serosa.
What is composition of tunica adventitia?
Type I and elastic fibers.
Where is the vasa vasorum located?
In the tunica adventitia of large arteries and veins.
Discuss elastic arteries?
Also called conducting arteries
Very thick tunica intima and media. Media has a lot of elastin in it.
Locations: All branches off aorta.
Possess vasa vasorum.
Function: Secondary pump and pressure reservoir.
Discuss muscular arteries?
Also called distributing arteries.
1 place where internal elastic laminae is VERY THICK.
Thick tunica media with more muscle than elastin and is equal to adventitia.
Locations: All the named arteries of the body.
Discuss arterioles?
2nd site of thick internal elastic laminae.
Function: Regulates peripheral resistance and is site of greatest pressure drop.
Site of vasoconstriction through α1.
What are the 5 variations in tunica media?
1) Thicker in lower extremity arteries
2) Thicker in coronary arteries
3) Thin in pulmonary arteries
4) Smooth muscle cells are longitudinal in joint capillaries
5) Composed of cardiac muscle in roots of great vessels.
3 things about continuous capillaries?
Active transcytosis
Pericytes are common
Continuous basal lamina.
4 things about fenestrated capillaries?
Loaded with pores bridged by diaphragms
No pericytes
Continuous basal lamina
Locations: Choroid plexus, choriocapillaries, glomeruli of kidney, pancreas, endocrine glands, intestinal mucosa.
4 things about sinusoidal capillaries?
Pores w/o diaphragms
Gaps btw endothelial cells
Discontinuous basal lamina
Locations: Anterior pituitary and adrenal cortex
4 new functions of endothelial cells?
Deactivate bradykinin and serotonin
Breakdown lipoproteins
Release prostacyclins
Convert Ang I into Ang II
Discuss veins?
Also called capacitance vessels
Contain 60% of blood volume (reservoir)
Very thick adventitia and no obvious demarcation between layers.
Discuss PCV's?
Pericytes in the walls
Run by themselves
Main site of diapedesis (therefore no smooth muscle wall)
Sensitive to temp change, inflammation and allergic reactions
What are the companion vessels to arterioles?
Muscular venules
Composition of cardiac skeleton and valves?
Cardiac skeleton is DICT
Valves are fibrous CT lined by endothelium.
What ion permeabilities account for each phase of the fast response AP?
Phase 4 - Inward rectifying K channel opens at hyperpolarized potentials.
Phase 0 - Fast Na channel
Phase 1 - IR K channel closes, transient opening K channel opens.
Phase 2 - L-type Ca channels open (Delayed rectifying K channels open but slowly)
Phase 3 - Delayed rectifier K channel opens all the way.
What blocks the fast Na channel?
Tetrodotoxin
Compare K perm during phase 4 versus phase 2?
K permeability is much higher at rest (phase 4) than phase 2
What ion permeabilities account for each phase of the slow response AP?
Only 3 phases
Phase 4 (unstable) - Na and Ca channels open.
Phase 0 - Ca channels depolarize (MUST KNOW).
Phase 3 - Same delayed rectifier K channel.
What changes can we make to phase 4 of slow response AP?
Nepi/sympathetics increase Ca and Na conductance thereby speeding up HR.
Ach opens K channels to hyperpolarize phase 4.
Ca channel blockers slow HR by slowing phase 4.
What do you call the passive tension in cardiac muscle?
Preload
What dictates the degree to which the cardiac muscle will shorten?
The length-tension relationship
What do the a, c and v waves represent on the atrial pressure curve?
a wave represents atrial systole causing increased pressure.
c wave represents atrial pressure increase due to blood forcing out of ventricle.
v wave represents atria filling up during ventricular systole.
What is stroke work?
Stroke volume x afterload
What is treppe or staircase phenomenon?
Increased HR prevents the full relaxation of ventricles due to residual Ca2+ which increases contractility.
What are the 3 types of intrinsic control of blood flow?
1) Myogenic control - Minor control. If you stretch the bv, then it reacts and contracts.
2) Metabolic regulation - Major control. Accumulation of metabolic byproducts results in vasodilation to restore perfusion.
3) Endothelium releases factors (nitric oxide) to control diameter.
Are the heart, brain and kidney controlled intrinsically or extrinsically?
Heart, brain and kidney is intrinsic control.
Sk. muscle is extrinsic control during rest.
What are fingerprints?
Primary epidermal ridges.
6 things about stratum basale?
1) Has unipotential stem cells.
2) These stem cells only divide at night and only give rise to keratinocytes. This is stimulated by EGF from dermis.
3) Attached to basal lamina by hemidesmosomes and desmosomes.
4) Only layer with hemidesmosomes.
5) Have keratin IF's as tonofilaments.
6) Contain melanocytes and merkel cells.
4 things about stratum spinosum?
1) 8-10 layers of keratinocytes attached by desmosomes.
2) Contain Langerhans cells.
3) Lots of keratin tonofilaments.
4) Keratinocytes contain membrane-coating granules and lamellar bodies.
3 things about stratum granulosum?
1) Has keratohyalin granules (fillagrin) which give it it's name.
2) The membrane-coating granules are released in this layer.
3) Apoptosis begins forming stratum corneum.
What do the keratohyalin granules do?
Contain and release fillagrin which bundles tonofilaments and deposits on P surface of cell PM forming waterproof barrier.
What forms the cell envelope?
Involucrin, fillagrin, tonofilaments and glycolipid from lamellar bodies.
Where is the waterproof barrier found?
In the stratum corneum
What is pemphigus?
Autoantibody against desmocolin/desmoglein of skin desmosomes. Skin blisters as fluid leaks into the stratum corneum.
Where are melanocytes found and what is their germ layer of origin?
Found in stratum basale and are from neural crest.
What are the clear cells in the stratum basale and why are they like this?
They are melanocytes and they are like this because they are attached to basal lamina with hemidesmosome but not to other cells with desmosomes.
Where is most melanin in the skin found?
In the keratinocytes of the stratum spinosum released by melanocytes from stratum basale.
Germ layer of origin of Langerhans cells?
Mesoderm - Monocyte precursor system.
What are the clear cells in the stratum spinosum?
Langerhans cells with no cell junctions.
Where are Birbeck granules found?
In langerhans cells of the stratum spinosum.
Where would you find Merkel cells?
In the stratum basale
Germ layer of origin of Merkel cells?
Neural crest
What are the differences between thin and thick skin?
Thick skin - Eccrine sweat glands
Thin skin - Hair follices, sebaceous glands and sweat glands.
No stratum lucidum in thin skin, thinner spinosum and thinner corneum.
Germ layer of origin? Epidermis vs. Dermis
Epidermis is from ectoderm.
Dermis is from mesoderm.
Characteristics of papillary layer of dermis?
Loose CT
Continuous capillary loops
Meissner's corpuscles
Characteristics of reticular layer of dermis?
DICT with type I collagen, elastic and reticular fibers.
Contains Pacinian corpuscle
What are the 3 blood vessel plexi in the dermis and which is most important?
1) Subpapillary plexus - most important, runs parallel to papillary layer and gives off capillary loops into papillae. Has an excess of venules and uses these for thermal regulation.
2) Subcutaneous plexus - in hypodermis
3) Cutaneous plexus - between papillary and reticular layers.
What 3 things give rise to skin color?
Eumelanin - imparts black and brown color.
Pheomelanin - imparts red color.
Oxyhemoglobin
Carotenes - in fat, give yellow color.
What sweat gland is found throughout the body?
Eccrine sweat gland
What hormone does the eccrine sweat duct respond to?
Aldosterone to decrease NaCl secretion.
Locations of adrenergic sweat glands?
Axilla, hands and feet.
Locations of apocrine sweat glands?
Axilla, areola, perianal region, eyelids and ear.
What hormone does the apocrine sweat gland respond to?
Androgens
Are apocrine and sebaceous glands found in thick skin?
No, only thin
Where do sebaceous and apocrine sweat glands release their product?
Onto the hair follicle
Locations of sebaceous glands?
Face, forehead, scalp
How do you control sebaceous glands?
Through hormones like androgens not through ANS.
What can the matrix stem cells of the hair bulb form?
Internal root sheath, cortex and medulla of hair.
What is the function of the follicular bulb?
It is where the arrector pili muscles insert. It has stem cells which regenerate the epidermis, hair shaft and sebaceous glands. Some of the cells also migrate down and replace the matrix stem cells.
Which part of the hair is a direct continuation of the stratum basale?
The outer root sheath