Human Anatomy - Epithelial tissue Flashcards Preview

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Flashcards in Human Anatomy - Epithelial tissue Deck (64):
1

What is a tissue?

A group of closely associated cells that perform related functions and are similar in structure.

2

What are the four tissue types?
What are their general functions?

Epithelial - covering
Connective - support
Nervous - control
Muscle - movement

3

Epithelial Tissue
______ a body surface or ____ a body cavity.
Forms parts of most ______.

Covers
Lines
Glands

4

What are the different functions of epithelial tissue?

protection
absorption, filtration and ion transport
excretion, secretion
Forms slippery surface

5

What are the special characteristics of epithelium?

1. Cellularity
2. Specialized contacts
3. Polarity
4. Supported by connective tissue
5. Avascular but innervated
6. Regeneration

6

Describe cellularity as it pertains to epithelial tissue.

Epithelial tissue is almost entirely composed of cells.

7

Describe specialized contacts as it pertains to epithelial tissue.

Cells of epithelial tissue are joined by special junctions.
These gap junctions allow for communication and for the cells to work as functional unit.

8

Describe polarity as it pertains to epithelial tissue.

Cell regions of the apical surface differ from the basal surface

9

How does epithelium receive nutrients without a dedicated blood supply?

Epithelia receive nutrients from underlying connective tissue.
Capillaries go through connective tissue but not through epithelium

10

Describe regeneration as it pertains to epithelial tissue.

Lost cells are quickly replaced by cell division.

11

How is epithelium classified?

First name of the tissue indicates the number of cells:
Simple - 1
Stratified 2 or more

Last name of the tissue describes the shape of the cells:
Squamous - flat
Cuboidal - cube-shaped
Columnar - column-shaped

12

How does structure relate to function?
Protection = ________
Transport = ________
Filter = _________
Stomach = ________

Stratified
Simple
Simple
Simple

13

Endothelium and mesothelium are both what type of epithelium?

Simple squamous

14

What is endothelium?

Slick lining of hollow organs in the circulatory system and in the inner layer of the heart.
Inner covering

15

What is mesothelium?

Lines peritoneal, pleural and pericardial cavities.
Covers the visceral organs of those cavities.
Middle covering.

16

What is the function of simple squamous epithelium?

Passage of materials by passive diffusion, osmosis and filtration.
Secretion in serous membranes.

17

Where is simple squamous epithelium located?

Renal corpuscles
Alveoli of lungs
Lining of heart, blood and lymphatic vessels (endothelium)
Lining of ventral body cavity and serosae (mesothelium)

18

What is the function of simple cuboidal epithelium?

Secretion and absorption

19

What is the location of simple cuboidal epithelium?

Kidney tubules
Secretory portions of small glands
Ovary surface

20

What lines the duct of a lumen?

Simple cuboidal epithelium

21

Describe simple columnar epithelium.

Single layer of column shaped epithelial cells.
Some bear cilia on their apical surface.
May contain goblet cells.

22

What is the function of simple columnar epithelium?

Absorption
Secretion of mucus, enzymes and other substances
Ciliated type propels mucus or reproductive cells

23

Where is simple columnar epithelium located?

Non-ciliated forms
- line GI tract, gallbladder, ducts of some glands
Ciliated form:
- lines small bronchi, uterine tubes, uterus

24

What is the purpose of cilia?

Move material across the surface of cells.

25

What do goblet cells do?

Secrete mucin

26

What is the lamina propria?

Connective tissue underlying mucus secreting membranes.

27

Pseudostratified epithelium:
All cells originate at the ________ _______
Only ______ cells reach the apical surface
May contain ______ ____ and bear _____
______ lie at varying heights within cells, giving the false impression of _________

Basement membrane
tall
goblet cells
cilia
Nuclei
stratification

28

Describe pseudostratified epithelium.

All cells originate at the basement membrane but, nuclei at varying heights give the impression of stratification.
May contain goblet cells and some bear cilia.
Only tall cells reach the apical surface.

29

What is the function of pseudostratified columnar epithelium?

Secretion of mucus
Propulsion of mucus by cilia

30

Where is pseudostratified epithelium located?

Non-ciliated:
- ducts of male reproductive tubes
- ducts of large glands
ciliated:
- lines trachea and most of URT

31

Describe the mucociliary escalator.

Mucus lubricates the respiratory system and catches bacteria and debris.
Cilia of the URT beats unidirectionally back up the URT to either expel the mucus or swallow it and digest it with stomach acid

32

What are the properties of stratified epithelia?

Contains two or more cells
Regenerate from below
Major role is protection
Named according to the shape of cells at the apical layer

33

Describe stratified squamous epithelium.

Multiple layers of flat cells. (squamous on apical layer)
Thickest epithelial tissue.
Adapted for protection against abrasion.
Can be keratinized or non-keratinized

34

Describe keratinized stratified squamous epithelium.

Dry
Located in the epidermis
Contains the protective protein keratin
Waterproof
Surface cells are dead and full of keratin

35

Describe non-keratinized stratified squamous epithelium.

Apical layer and layers deep to it remain moist.
Forms moist lining of body openings.
Wet

36

What is the function of stratified squamous epithelium?

Protects underlying tissues from abrasion.

37

Where is stratified squamous epithelium located?

Keratinized - epidermis
non-keratinized - mouth, esophagus, anus, vagina, urethra

38

What is the function of stratified cuboidal epithelium?

Protection

39

Where is stratified cuboidal epithelium located?

Forms the ducts of:
- mammary glands, salivary glands, largest sweat glands

40

Stratified cuboidal epithelium is generally ___ layers.

2

41

Describe stratified columnar epithelium.

Multiple layers;
Basal cells are generally cuboidal, apical cells are elongated

42

What is the function of stratified columnar epithelium?

Protection and secretion

43

Where is stratified columnar epithelium located?

Rare
Found in male urethra and large ducts of some glands

44

Describe transitional epithelium.

Basal cells are usually cuboidal/columnar and apical cells are squamous.
Not as many layers as stratified squamous.

45

What is the function of transitional epithelium?

Stretches and permits distension of urinary bladder

46

Where is transitional epithelium located?

lines inside of hollow urinary organs.

47

What are exocrine glands?

Glands who secrete their products onto the body surface or into a body cavity.
Local activity

48

Which glands are exocrine?

Mucus-secreting glands
Salivary glands
Sweat and oil glands
Liver and pancreas

49

Describe the goblet cell.

Produce the glycoprotein mucin.
Unicellular exocrine gland.

50

What is the purpose of mucin?

When combined with water, becomes mucus which, protects and lubricates internal body surfaces.

51

Where is the mucin located in a goblet cell?

Secretory vesicles in goblet cells contain mucin.

52

What are the different epithelial surface features?

Apical:
Cilia and Microvilli
Basal:
Basal lamina
Basement membrane

53

What are microvilli?

Finger-like extensions of plasma membrane which function to increase surface area.
Important for secretion and absorption.

54

Where are microvilli located?

Small intestine and kidney

55

What are cilia?

Whip-like, highly motile extensions of apical surface membranes.
Move in one direction to push material over the surface of epithelial tissue

56

What is the basal lamina?

Acellular supporting sheet between the epithelial tissue and underlying connective tissue.
Consists of proteins secreted by epithelial cells

57

What are the functions of the basal lamina?

Selective filter - prevents inside-out/outside-in movement of material
Scaffolding: for tissue regeneration

58

What is the basement membrane?

Basal lamina + reticular lamina
Often interchangeable with basal lamina.

59

What is the basis of a scar?

Caused by the destruction of the scaffolding of the basement membrane leading to improper tissue regeneration.

60

What is the purpose of stitching?

Minimize appearance of a scar by getting tissue close enough for communication.

61

Kartagener's syndrome is an _______ issue.
Diabetes is a ______ issue.

Apical
Basal

62

What is Kartagener's Syndrome?

Immotile cilia in which dynein arms fail to form.

63

What are symptoms of Kartagener's?

Chronic respiratory infections, infertility, hearing loss, frequent headaches due to stagnant CSF.

64

If left untreated, diabetes can cause _______ of the basement membrane. Why?

Thickening
Increased glucose causes thickening of basement membrane.
Symptoms include loss of eyesight and kidney problems.