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Flashcards in Epithelium Deck (33):
1

Two sides of Epithelium

Apical Basolateral

2

Characteristics of Epithelium

PARCA
Polar
Avascular
Attached
Regeneration
Cellularity (cell junctions)

3

Cellularity (in Epithelial cells)

Occluding (Tight) junctions (Zonulae occludens)
Prevents passage of water and solutes
Prevents enzymes and wastes in the lumen at the apical surface to reach the basolateral surface.
Linking the cytoskeletons of adjacent cells and stabilizing tight junctions
Gap junctions
allow rapid communication
Held together by channel proteins (junctional proteins, connexons)
Allow ions to pass
Coordinate contractions in heart muscle
Desmosome (anchoring junctions)
allow mechanical stress
Provides strength to epithelium laterally and basally

4

Tight junctions

Lipid portion of the membrane bound, Prevent entry, Apical surface of the intestinal lumen

5

Gap Junctions

Transmembrane bound, Allow communication, Cardiac muscle

6

Desmosome

Adhesion molecules proteoglycan and cytoskeleton bound,Maintain the strength, Skin
Between cardiac muscle cells

7

Polarity

Apical surfaces:
Microvilli increase absorption or secretion
Cilia (ciliated epithelium) move fluid
Basal surfaces
Cell to extracellular matrix
Lateral surfaces
Occluding junction
Anchoring
Communication

8

Structure of Microvilli

Simple Surface Area

9

Structure of Cilia

Stratified or pseudo stratified

10

Attachment to Basalir Lamina

Clear layer (Lamina lucida)
Thin layer
Secreted by epithelia
Barrier to proteins
Dense layer (Lamina densa)
Thick fibers
Produced by connective tissue
Strength and filtration

11

Amount of Insensible Persperation

500 mL

12

Avascularity of Epithelial Cells

Epithelial cells derive support by diffusion from blood vessels in underlying connective tissue
Thickness of epithelia cannot be greater than the distance over which nutrients can diffuse from vascular source.
Our skin is covered by epithelium. And each day, we lose about 500 ml of water via Insensible Perspiration.
In what situation do we need to worry about insensible perspiration?

13

Regeneration of Epithelial

Epithelia are replaced by division of germinative cells (stem cells)
Near basal lamina

14

Layers of Epithelium

Come (corny)
Lets (lucidum)
Get (Granulosum)
Sun (spinosum)
Ger (Germinativum)
Burned (Basal)

15

Simple/Stratified Cuboidal

Simple cuboidal epithelium
Secretion and absorption (kidneys)
Ducts
Stratified cuboidal epithelia
Sweat ducts and mammary ducts

16

Stratified Cuboidal

lining of some ducts (rare)
Function; protection, secretion, absorption

17

Transitional Epithelium

Urinary Bladder
Empty (relaxed/taller) Full (stretched/lower)

18

Scalloped Surface Cells

Transitional

19

Columnar Epithelium

Simple columnar epithelium
Absorption and secretion
Stratified columnar epithelium
Protection
Some secretion
Pseudo-stratified ciliated columnar epithelium
Secretion
Protection

20

simple Columnar locations

stomach, intestines, gallbladder, uterine tubes, collecting ducts of kidneys,

21

Pseduo-Stratified Ciliated Columnar

ciliated, basal side connected to loose connective tissue

22

stratified Columnar

epiglottis, pharynx, anus, mammary glands, salivary glands, ducts

23

Glandular Epithelium

Endocrine=into interstitial fluid. Exocrine=to epithelium via ducts

24

Mode of Glandular Secretion (Epithelium)

Holocrine (pimple-sebum, sebacious), Apocrine mammary glands mother ape), Merocrine sweat glands

25

Holocrine

Sebum, ducts, oil

26

Apocrine

produced in Golgi (as well as merocrine), Mammary, sweat

27

Merocrine

Sweat gland, water and electrolytes, widely distributed

28

4 types Membranes

Mucous, Serous, cutaneous, synovial

29

Mucousa

Epithelium + Lamina propria

30

Serous membrane

Line cavities not open to the outside
Are thin but strong
Have fluid transudates to reduce friction
Have a parietal portion covering the cavity
Have a visceral portion (serosa) covering the organs

31

Serous Membrane

Pleura:
Lines pleural cavities
Covers lungs
Peritoneum:
Lines peritoneal cavity
Covers abdominal organs
Pericardium:
Lines pericardial cavity
Covers heart

32

Cutaneous

Is skin, surface of the body
Thick, waterproof, and dry

33

Synovial

Lines moving, articulating joint cavities with a layer of connective tissue
Produces synovial fluid (lubricant)
Type A: Macrophage-like to clean
Type B: Synovial cell to secrete
Protects the ends of bones
Lack a true epithelium