Tissues/cells WSCU Flashcards
Epithelial Tissue
- always found covering or lining all body surfaces all visible surfaces and all lining
- includes glands and epithelium (glands are secretory)
- is avascular
- forms protective barrier that regulates permeability
- cells may show polarity
- cells attach via CAM cell adhesion mechanism
Epithelial tissue
- physical protection
- control permeability
- provide sensation
- produce specialized sensation
Epithelial tissue specialization
- preform secretory functions
- preform transport
- maintain physical integrity
- ciliated epithelium move particles across surface
Epilthium polarity
Uneven distribution of organelles
- common characteristic for the organelles to be crammed into one side of the cell
Epithelial tissue integrity
- Cells attach via CAM cell adhesion molecules
- Cells attach at specialized cell junctions
- tight junctions
- desmosomes
- gap junctions
- hemi-desmosomes
Tight junctions
Fusion of cell membranes
Leak proof cell protects lower membrane
Acts as protective barrier
Keeps things from seeping down into lower tissues bacteria, water etc
Desmosomes
One cell to another using CAM
- sunburns peel a piece of skin off sheets are caused by desmosomes
- looks like zipper
GAP junction
Permits the flow of ions
Allows cells to communicate and act as a team instead of individual
Hemidesmosomes
-act like root and anchor epithelium to underlying tissues
Basal Lamina (basement membrane)
-basal lamina attaches to underlying surface
~lamina lucida (acts as barrier restricts movement of proteins and lg molecules from underlying connective tissue)
~lamina densa (gives basement membrane its strength)
-Germinative cells replace short lived epithelial cells (reproductive)
Simple epithelium
One cell layer thick
Stratified epithelium
Two or more cells thick
Squamous
Irregular shaped (fried egg cell)
Cuboidal
Square nucleus right in middle
Columnar
Rectangular
Classification of epithelium
- apical layer surface to determine overall shape
- simple
- stratified
- squamous
- cuboidal
- columnar
Simple epithelium
- found deep in the body well protected
Stratified epithelium
Close to surface of body
Stratified squamous Epithelium
Location: surface of skin, lining of mouth throat esophagus, rectum, anus, vagina
Function: provides physical protection against abrasion, pathogens, chemical attack
Can be keratinized or not
Simple squamous epithelium
Location: deep in body, lining ventral body cavities, endothelia lining heart and blood vessels, portion of kidney tubules, inner lining of cornea, alveoli of lungs.
Function; reduces friction, controls vessel permeability, preforms absorption and secretion
Bigger surface area so can
Simple Cuboidal Epithelia
Locations-deep inside body glands, ducts, portions of kidney tubules, thyroid gland
Functions: limited protection, secretion and absorption
Stratified cuboidal epithelia
Location: lining some ducts (rare) sweat gland duct
Functions: protection, secretion, absorption
Transitional Epithelium
Locations: urinary bladder, renal pelvis, ureters
Function: permits expansion and recoil after stretching.
Simple Columnar Epithelia
Locations: lining of stomach, intestine, gallbladder, uterine tubes, collecting ducts of kidneys.
Function: protection secretion, absorption
Permits diffusion and absorption; (any where you see simple epithelia absorption and secretion will be found example; small intestine 90% of all nutrients absorbed we don’t have time to wait for it to absorb through multiple layers need it to be fast) absorbs almost instantaneously, same as with the alveoli in lungs)
PseudoStratified columnar epithelia
Location: lining of nasal cavity, trachea, and bronchi, portions of male reproductive tract
Function: protection and secretion
looks like multiple layers of cells but they are all touching the basal lamina/basement membrane
Stratified columnar epithelia
Locations: small areas of the pharynx, epiglottis, anus, mammary gland, salvary gland ducts, urethra
function: PROTECTION
Glandular epithelium
Exocrine: secrete through ducts onto surface of gland
Endocrine glands: release hormones into surrounding tissue
Merocrine glands
Release product through exocytosis(onto surface of cell).
-through secretory vesicles produced by Golgi
Examples: saliva, sweat, mucus
Apocrine
- involves the loss of both a product and cytoplasm
Example: milk from mammary gland
- top part of cell filled with secretory vesicles that the cell then pinches off top part of cell and product released mixed with the cytoplasm. Cell then regenerates itself.
Holocrine
-destroys cell with release like oil gland
When product is produced the cell bursts open destroying the cell and releases the product
Steps
- Mitosis replaces lost cells near basement membrane
- Cells produce secretion increasing cell size
- Cells burst, releasing cytoplasmic contents
Connective tissue
Establishes a structural framework
Transports fluids and dissolved materials
Protects delicate organs
Supporting surrounding and interconnecting tissues
Stores energy reserves
Defends body from microorganisms like bacteria
Connective tissue
- found below basement membrane/basal lamina
- highly vascular
- very sensitive lots of pain and pressure receptors
Connective tissue proper (two types)
- Loose
- Dense
- contains varied cell population
- contains various fiber types
- a syrupy ground substance