Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
104 Cards in this Set
- Front
- Back
|
Tissues (114)
|
- groups of cells that are similar in structure and perform a common or related function
- organized into organs and separating barriers |
|
|
Four Primary Tissue Types
|
- Epithelial (covering)
- Connective (support) - Nervous (control) - Muscle (movement) |
|
|
Epithelial Tissue
|
- sheet of cells that covers a body surface or lines a body cavity
- forms boundaries between diff environments |
|
|
Epithelial Tissue Occurs as:
|
1. covering and lining epithelium and;
2. glandular epithelium |
|
|
Covering and Lining Epithelium
|
- forms the outer layer of skin, lines the open cavities of the cardiovascular, digestive, and respiratory systems, and covers the walls and organs of the closed ventral body cavity
|
|
|
Glandular Epithelium
|
- fashions the glands of the body
|
|
|
Special Characteristics of Epithelium
|
1. exhibits polarity
2. specialized contacts 3. supported by connective tissue 4. Avascular but innervated 5. Regeneration |
|
|
Epithelium: Polarity
|
- all epithelia have an apical surface and a basal surface
- exhibit apical-basal polarity - apical surfaces can have microvilli and/or cilia |
|
|
Epithelium: Apical Surface
|
- an upper free surface exposed to the body exterior or the cavity of an internal organ
|
|
|
Epithelium: Basal Surface
|
- lower attached part of epithelium
- attaches to underlying tissues which is almost always going to be a connective tissue - in general, is specialized for attachment |
|
|
Epithelium: Apical-Basal Surface
|
- all epithelia exhibit A-B P meaning that the cell regions near the apical surface differ from those near the basal surface in both structure and function.
|
|
|
Epithelium: Apical Surfaces: Microvilli
|
- bigger than cilia
- cytoplasmic extensions of cell - increase surface area of cell - if a secretory cell, MV offer greater surface thru which more secretion can occur across the apex of cell |
|
|
Epithelium: Apical Surfaces: Cilia
|
- tiny hairlike projections
- propel substances along their free surface |
|
|
Epithelium: Specialized Contacts
|
- except for glandular epithelia, epithelial cells fit close together to form continuous sheets
- adjacent cells are bound together by tight junctions and desmosomes - tight junctions help keep proteins in the apical region of the plasma membrane from diffusing into the basal region, and thus help to maintain epithelial polarity |
|
|
Epithelium: Supported by Connective Tissue
|
- all epithelial sheets rest upon and are supported by connective tissue
- just deep to the basal lamina is the reticular lamina, a layer of extracellular material containing a fine network of collagen protein fibers that "belongs to" the underlying connective tissue - together, they form the basement membrane which reinforces the epithelial sheet, helping it to resist stretching and tearing forces, and defines the epithelial boundary |
|
|
Epithelium: Avascular but Innervated
|
- not avascular meaning it contains no blood vessels
- is innervated which means they are supplied by nerve fibers - epithelial cells are nourished by substances diffusing from blood vessels in the underlying connective tissue |
|
|
Epithelium: High Regeneration
|
- high regenerative capacity
- if their apical-basal polarity and lateral contacts are destroyed, epithelial cells begin to reproduce themselves rapidly - SLA epithelial cells receive adequate nutrition, they can replace lost cells by cell division |
|
|
Epithelium: Highly Cellular
|
- exhibit high cell density
- cf: conenctive tissue has low cell density - epithelial tissues are highly cellular bc are a tissue of surfaces; are tightly held together with desmosomes and tight junctions which keeps this an intact sheet with very little extracellular space in between |
|
|
Classification of Epithelia (116)
|
- each epithelium is given two names
- first name indicates the number of cell layers present - second name describes the shape of its cells |
|
|
Number of Cell Layers: 2
|
- simple epithelia
- stratified epithelia |
|
|
Simple Epithelia
|
- consists of a single cell layer
- typically found where absorption, secretion and filtration occur and a thin epithelial layer is desirable |
|
|
Stratified Epithelia
|
- more than one layer
- common in high-abrasion areas where protection is important such as the skin surface and the lining of the mouth |
|
|
Three Shapes of Epithelial Cells
|
- squamous cells: flattened and scale-like
- cuboidal cells: boxlike, approximately as tall as they are wide - columnar cells: tall and column shaped |
|
|
Simple Epithelia
|
- most concerned with absorption, secretion and filtration; not really protection
- simple squamous epithelium - simple cuboidal epithelium - simple columnar epithelium - pseudostratified columnar epithelium |
|
|
Simple Squamous Epithelium
|
DESCRIPTION: single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm, the simplest of the epithelia
FUNCTION: allows passage of materials by diffusion and filtration in sites where protection is not important LOCATION: kidney, forms part of the filtration membrane; air sacs of lungs; lining of heart; blood vessels; lympatic vessels; lining of ventral body cavity |
|
|
Two Special Simple Squamous Epithelia
|
- endothelium
- mesothelium |
|
|
Endothelium
|
- "inner covering"
- provides a slick, friction-reducing lining in lymphatic vessels and in all hollow organs of the cardiovascular system -- blood vessels and the heart - capillaries consist exclusively of endothelium, and its exceptional thinness encourages the efficient exchange of nutrients and wastes bt the bloodstream and surrounding tissue cells |
|
|
Mesothelium
|
- "middle covering"
- found in serous membranes lining the ventral body cavity and covering its organs |
|
|
Simple Cuboidal Epithelium
|
DESCRIPTION: single layer of cubelike cells with large, spherical central nucleu
FUNCTION: secretion and absorption LOCATION: kidney tubules, ducts and secretory portions fo small glands, ovary surface |
|
|
Simple Columnar Epithelium
|
DESCRIPTION: single layer of tall cells with round to oval nucleu; some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells)
FUNCTION: absorption; secretion of mucus, enzymes, and othe rsubstsances; ciliated type propels mucus (or reproductive cells) by ciliary action LOCATION: nonciliated type lines most of the digestive tract (stomach to anal canal), gallbladder and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus |
|
|
Pseudostratified Columnar Epithethelium
|
DESCRIPTION: single layer of cells of differing heights; some not reaching the free surface but all touching the basement membrane
FUNCTION: secretion, particularly of mucus; propulsion of mucus by ciliary action; absorbs substances LOCATION: nonciliated type in male's sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract |
|
|
Stratified Epithelia
|
- contain more than one cell layer
- regenerate from below; basal cells divide and push apically to replace the older surface cells - more durable than simple epithelia and protection is their major role |
|
|
Stratified Squamous Epithelium
|
DESCRIPTION: the most widespread of the stratified epithelia; thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers
FUNCTION: protects underlying tissues in areas subjected to abrasion LOCATION: nonkeratinized type forms the moist linings of the esophagus, mouth and vagina; keratinized variety forms the epidermis of the skin, a dry membrane |
|
|
Transitional Epithelium
|
DESCRIPTION: resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch; distends and stretches
FUNCTION: stretches readily (looks squamous); ability of transitional cells to change their shape which allows a greater volume of urine to flow through a tubelike organ; in bladder allows more urine to be stored LOCATION: lines the ureters, urinary bladder, and part of the urethra |
|
|
Glandular Epithelia
|
comprised of glands
|
|
|
Gland
|
-consists of one or more cells that make and secrete (export) a particular product called a secretion.
- classified either as endocrine (internally secreting) or exocrine (externally secreting) - either unicellular or multicellular |
|
|
Secretion
|
an aqueous (water-based) fluid that usually contains proteins but there is variation.
|
|
|
Unicellular Glands
|
- typically found in walls of digestive, respiratory tract
|
|
|
Multicellular Glands
|
- also found in walls of organs but deep inside typically inside muscle layer
|
|
|
Endocrine Glands
|
- often called ductless glands bc lose eventually lose their ducts
- produce hormones, regulatory chemicals that they secrete by exocytosis directly into the extracellular space. - most EGs are compact multicellular organs. |
|
|
Exocrine Glands
|
- secrete onto the body surface (skin) or into body cavities (like the digestive tract which is considered external to body)
- unicellular glands secrete directly by exocytosis; multicellular glands do so by epithelium-walled duct that transport the secretion to the epithelial surface - EGs include mucous, sweat, oil, and salivary glands, the liver, pancreas |
|
|
Structural Classification of Multicellular Exocrine Glands (123)
|
- either simple or compound
- either tubular, alveolar, or tubulalveolar |
|
|
Simple Glands
|
- have an unbranched duct
|
|
|
Compound Glands
|
- have a branched duct
|
|
|
Tubular Gland
|
- secretory cells form tubes
|
|
|
Alveolar (or Acinar) Gland
|
- if the secretory cells form small, flasklike sacs
|
|
|
Tubulalveolar Gland
|
- if gland has both types of secretory units
|
|
|
Modes of Secretion
|
- merocrine gland
- holocrine gland - apocrine gland |
|
|
Merocrine Glands
|
- most multicellular exocrine glands are merocrine glands which secrete their products by exocytosis as they are produced.
- includes pancreas, most sweat glands, salivary glands |
|
|
Holocrine Glands
|
- secretory cells of HGs accumulate their product within them until they rupture; self-destruct and release product into surrounding fluid
- includes sebaceous glands of the skin |
|
|
Apocrine Glands
|
- just apex of cell ruptures and releases products and base of cell repairs itself
- like holocrine glands, AGs accumulate their products, but only just beneath the free surface. Eventually, the apex of the cell pinches off, releasing the secretory granules and a small amount of cytoplasm - doesn't exist in humans |
|
|
Connective Tissue
|
- found everywhere in body
- most abundant and widely distributed of the primary tissues |
|
|
4 Main Classes of Connective Tissue
|
1. connective tissue proper (fat and the fibrous tissue of ligaments)
2. cartilage 3. bone tissue 4. blood |
|
|
Major Functions of Connective Tissue
|
1. binding and support
2. protection 3. insulation 4. transportation of substances within the body (blood) |
|
|
Common Characteristics of Connective Tissue
|
1. common origin
2. degrees of vascularity 3. extracellular matrix 4. low degree of cellularity |
|
|
Common Origin of Connective Tissue
|
- all connective tissues arise from mesenchyme (stem cells) and have a kinship
- most of stem cells are going to be found in bone, and clustered in specific areas of bone |
|
|
Connective Tissue: Degrees of Vascularity
|
- can range from avascular (cartilage), to poorly vascularized (dense connective tissue) to a rich supply of blood vessels
|
|
|
Connective Tissue: Extracellular Matrix
|
- all other primary tissues are composed mainly of cells, but CTs are largely nonliving EM which separates, often widely, the living cells of the tissue.
- Bc of its matrix, CT is able to bear weight, withstand great tension and endure abuses, such as physical trauma and abrasion that no other tissue would be able to tolerate - mostly water |
|
|
Structural Elements of Connective Tissue
|
3 main elements:
- ground substance - fibers - cells - together, ground substance and fibers make up the extracellular matrix |
|
|
Ground Substance
|
- the unstructured material that fills the spaces between the cells and contains the fibers
- composed of interstitial fluid, cell adhesion proteins, and proteoglycans - holds large amts of fluid and functions as a molecular sieve, or medium, thru which nutrients and other dissolved substances can diffuse bt the blood capillaries and the cells. |
|
|
Cell Adhesion Proteins
|
- serve mainly as a connective tissue glue that allows connective tissue cells to attach themselves to matrix elements
|
|
|
Proteoglycans
|
- consist of a protein core to which glycosaminoglycans (GAGs) are attached
|
|
|
Fibers
|
- provide support
- there are 3 types of fibers found in connective tissue matrix: - collagen - elastic - reticular |
|
|
Collagen Fibers
|
- most common
- looks like large, single-stranded fiber - comprised of collagen which are cross-linked fibrils which make them extremely tough and provide high tensile strength (the ability to resist longitudinal stress) - the higher the tensile strength, the greater the force needed to separate, so collagen doesn't stretch very well - collagen fibers are stronger than steel fibers; spiderwebs have even higher tensile strength - called white fibers |
|
|
Connective Tissue: Elastic Fibers
|
- long, thin fibers that form branching networks in the extracellular matrix
- contain a rubberlike protein, elastin, that allows them to stretch and recoil like rubber bands - found where greater elasticity is needed like in the skin, lungs, and blood vessel walls - often called yellow fibers |
|
|
Connective Tissue: Reticular Fibers
|
- short, fine, collagenous fibers with a slightly different chemistry and form
- continuous with collagen fibers and they branch extensively, forming delicate networds that surround small blood vessels and support the soft tissue of organs |
|
|
Connective Tissue: Cells
|
- each major class of connective tissue has a fundamental or resident cell type that exists in immature and mature forms
|
|
|
Primary Blast Cell Types by Connective Tissue Class
|
1. Connective Tissue Proper: fibroblast
2. Cartilage: chondroblast 3. Bone: Osteoblast |
|
|
Blast
|
- undifferentiated cells which are actively mitotic cells that secrete the ground substance and the fibers characteristic of their particular matrix
|
|
|
Cyte
|
- once the blasts synthesize the matrix, the blast cells assume their less active, mature mode
|
|
|
Characteristic of Connective Tissue: Low Degree of Cellularity
|
- df epithelial tissue which was highly cellular
- have fat cells, mast cell (type of white blood cell), lymphocyte, macrophage (dispose of dead tissue cells), fibroblast (the cell that makes that particular connective tissue) - see a lot of white space; most of CT voulume is ground substance or matrix |
|
|
4 Subclasses of Connective Tissue
|
- connective tissue proper
- cartilage - bone - blood |
|
|
Blast vs. Cyte
|
- whenever see blast, means an immature cell type, not yet fully developed
- when fully developed, called fibrocyte, for ex. |
|
|
Connective Tissue Proper
|
- starts out as mesenchyme (stem cells) which differentiate and become more complex and specialized
- process of differentiation makes the daughter cells more complex and more specialized - mesenchyme are generic cells that can become bone, cartilage cells or can become fibroblasts |
|
|
Fibroblasts
|
- can produce GAGs, elastin, collagen, etc.
- can do so bc more metabolically active than fibrocytes - these are cells that are metabolically active and used to build tissue - fibrocytes, by contrast, are less metabolically active and used to maintain tissue - fibroblasts produce CT proper |
|
|
Cartilage
|
- produced by chondroblasts
- differentiate into chondrocytes |
|
|
Bone
|
- produced by osteoblasts
- differentiate into osteocytes |
|
|
Blood
|
- produced by hemocytoblasts
- differentiate itno hemocytes |
|
|
Connective Tissue Proper: Two Subclasses
|
- loose connective tissue
- areolar, adipose, reticular - dense connective tissue - dense regular - dense irregular - elastic |
|
|
Loose CT: Areolar Connective Tissue
|
DESCRIPTION: gel-like matrix with all three fiber types; cells, fibroblasts, macrophages, mast cells, and some white blood cells
FUNCTION: packing tissue, mostly matrix, very light, used to pack aruond other issue types and organs; its macrophages phagocytize bacteria; plays imp role in inflammation; holds and conveys tissue fluid LOCATION: widely distributed under epithelia of body; e.g. forms lamina propria of mucous membranes; packages organs, surrounds capillaries |
|
|
Loose CT: Adipose (Fat) Tissue
|
DESCRIPTION: matrix as in areolar, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet; higher cell density than areolar
FUNCTION: provides reserve food fuel; insulates against heat loss; supports and protects organs; when fulled, used for packing and insulation LOCATION: under skin in the hhypodermis; around kidney and eyeballs; within abdomen; in breasts |
|
|
Loose CT: Reticular
|
DESCRIPTION: network of reticular fibers in a typical loose ground substance; reticular cells lie on the network
FUNCTION: fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages; is associated with the blood and lymphatic functions; very specialized LOCATION: lymphoid organs (lymph nodes, bone marrow, and spleen). |
|
|
Dense Regular Connective Tissue
|
DESCRIPTION: primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast; strong along long axis and weak along orthogonal (perpendicular)
FUNCTION: attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction LOCATION: common in tendons, most ligaments, aponeuroses |
|
|
Dense Irregular Connective Tissue
|
DESCRIPTION: primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast
FUNCTION: able to withstand tension exerted in many directions; provides structural strength; tends to be stronger than regular tissue LOCATION: fibrous capsules of organs and of joints; dermis of the skin; submucosa of digestive tract |
|
|
Elastic Connective Tissue
|
DESCRIPTION: dense regular connective tissue containing a high proportion of elastic fibers
FUNCTION: allows recoil of tissue following stretching; maintains pulsative flow of blood through arteries; aids passive recoil of lungs following inspiration LOCATION: walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes |
|
|
Cartilage
|
- stands up to both tension and compression
- has qualities bt dense connective tissue and bone - is avascular and lacks nerve fibers - receives nutrients by diffusion from blood vesseuls located in the connective tissue membrane (perichondrium) surrounding it - chondroblasts produce new matrix until the skeleton stops growing at the end of adolescence. |
|
|
Does Cartilage Grow Fast?
|
NO. Bc cartilage is avascular and aging cartilage cells lose their ability to divide, injured cartilages heal slowly.
|
|
|
Three Types of Cartilage
|
1. Hyaline Cartilage
2. Elastic Cartilage 3. Fibrocartilage |
|
|
Hyaline Cartilage
|
- "gristle"
- is most abundant cartilage type in body - provides firm support with some pliability DESCRIPTION: amorphous but firm matrix; collagen fibers form an imperceptible network; chondroblasts produce the matrix and when mature (chondrocytes) lie in lacunae FUNCTION: supports and reinforces; has resilient cushioning properties; resists compressive stress LOCATION: forms most of the embryonic skeleton; covers the end of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachea, and larynx |
|
|
Elastic Cartilage
|
DESCRIPTION: similar to hyaline cartilage, but more elastic fibers in matrix
FUNCTION: maintains the shape of a structure while allowing great flexibility; found where strength and exceptional stretchability are needed LOCATION: forms the "skeletons" of the external ear and the epiglottis |
|
|
Fibrocartilage
|
DESCRIPTION: matrix similar to but less firm than that in hyaline cartridge; thick collagen fibers predominate; bc it is compressible and resists tension well, fibrocartilage is found where strong support and the ability to withstand heavy pressure are required
FUNCTION: tensile strength with the ability to absorb compressive shock LOCATION: intervertebral discs; pubic symphysis; discs of knee joint (menisci) |
|
|
Connective Tissue: Bone (Osseous Tissue)
|
DESCRIPTION: hard, calcified matrix containing many collagen fibers; osteocytes lie in lacunae; very well vascularized
FUNCTION: bone supports and protects (by enclosing); provides lever for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation (hematopoiesis) LOCATION: bones |
|
|
Connective Tissue: Blood
|
DESCRIPTION: red and white blood cells in a fluid matrix (plasma); the fluid within blood vessels; is classified as a connective tissue bc it developsf rom mesenchyme and consists of blood cells surrounded by a nonliving fluid matrix called blood plasma
FUNCTION: transport vehicle for the cardiovascular system, carrying nutrients, wastes, respiratory gases, and many other substances throughout the body LOCATION: |
|
|
Nervous Tissue
|
DESCRIPTION: main component of nervous system which regulates and controls body functions; contains neurons, highly specialized nerve cells that generate and conduct nerve impulses; typically, are branching cells with cytoplasmic extensions or processes.
FUNCTION: transmit electrical signals from sensory receptors and to effectors (muscles and glands) which control their activity LOCATION: brain, spinal cord, and nerves |
|
|
Nervous Tissue Processes
|
- processes allow neurons to:
1) respond to stimuli (a role of the processes called dendrites) and 2) to transmit electrical impulses over substantial distances within the body (the job of axons, which may be very long and myelinated, that is, covered with a fatty sheath that increases the speed of nerve transmission |
|
|
Muscle Tissue
|
- highly cellular
- well-vascularized - responsible for most types of body movement |
|
|
Myofilaments
|
- possessed by muscle cells and are elaborate versions of the actin and myosin filaments that bring about movement or contraction in all cell types
|
|
|
Three Kinds of Muscle Tissue
|
- skeletal: is voluntary and striated
- cardiac: is involuntary and striated - smooth: is involuntary and smooth |
|
|
Skeletal Muscle
|
DESCRIPTION: long, cylindrical, multinucleate cells, obvious striations
FUNCTION: voluntary movement, locomotion, manipulation of the environment, facial expression, voluntary control LOCATION: in skeletal muscles attached to bones or occasionally to skin |
|
|
Cardiac Muscle
|
DESCRIPTION: striated; are generally uninucleate and are branching cells that fit together tightly at unique junctions called intercalated discs
FUNCTION: as it contracts, it propels blood into the circulation; involuntary control LOCATION: the walls of the heart |
|
|
Smooth Muscle
|
DESCRIPTION: spindle-shaped cells with central nuclei; no striations; cells arranged to form sheets
FUNCTION: propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control LOCATION: mostly in the walls of hollow organs |
|
|
Covering and Lining Membranes
|
- cutaneous membrane: (the skin) covers the body surface
- mucous membrane: line body cavities open to the exterior like those of the hollow organs of the digestive, respiratory, and urogenital tracts - serous membrane: line body cavities closed to the exterior |
|
|
Tissue Repair
|
see book, pps. 139-141
|
|
|
Regenerative Capacity of Different Tissues
|
- generate well: epithelial tissues, bone, areolar connective tissue, dense irregular connective tissue, blood-forming tissue
- moderate capacity for regeneration: smooth muscle and dense regular connective tissue - weak regenerative capacity: skeletal muscle and cartilage - no functional regenerative capacity: cardiac muscle and the nervous tissue in the brain and spinal cord |
