TOB S2 - Glands and Internal surfaces of the body Flashcards Preview

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Flashcards in TOB S2 - Glands and Internal surfaces of the body Deck (56):
1

Define a gland.

A collection of epithelial cells specialised for secretion.

2

List the ways in which glands are classified.

Destination of secretion
Structure of gland
Nature of secretion
Method of discharge

3

How are glands classified by secretion destination?

Exocrine glands secrete into ducts or onto surfaces

Endocrine glands are ductless, secrete directly into blood

4

How are the secretory portion of glands classified by structure?

Uni/multicellular

5

How are multicellular glands classified? (think shape of secretory portion)

Alveolar, tubular, coiled, branched

6

What are the different types of ducts present in glands?

Simple
Complex (branched)

7

How are glands classified by nature of secretion?

Mucous or serous

8

Describe mucous secretion.
How does it react to H&E staining?

Contains mucus rich in mucin (glcosylated polypeptides)
Stains poorly with H&E stain

9

Describe serous secretions
How does it react to H&E staining?

Watery, no mucus, enzymes present
Stains pink with H&E stain

10

What are the three methods of secretion?

Merocrine, Apocrine, Holocrine

11

Describe the process of merocrine secretion

Membrane bound vesicle fuses with plasma membrane

Contents released into intracellular space

Additional area of plasma membrane recovered

12

Describe the process of Holocrine secretion.

Disintegration of whole cell releases all cellular contents

13

Describe the process of Apocrine secretion

Non membrane bound structures (eg. Lipids) approach apical cell membrane, are enveloped by cytoplasm then the plasma membrane.

Buds off releasing vesicles into intercellular space

Large amounts of plasma membrane lost (decapitation)

Plasma membrane added to to recoup loss.

14

What is endocytosis?

The opposite process to exocytosis (merocrine secretion)

Material outside cell is engulfed by plasma membrane and buds off into the cell cytoplasm.

15

Describe transepithelial transport

Material enters cell through endocytosis

Shuttled through cytoplasm in transport vesicle

Material is secreted on the other side of epithelial cell via merocrine secretion (exocytosis)

16

Describe the structure of the Golgi apparatus

Layers of disk shaped cisternae

Flattened on one side, concave on the other

Swellings at the edges of cisternae (bud off to form vesicles)

17

Describe the functions of the Golgi apparatus

Sorting and packaging of contents into vesicles

Glycosylation of proteins and lipids

Transport

18

Where do vesicles from the Golgi apparatus end up?

Majority exocytosed

Some retained (eg lysosomes)

Some enter plasma membrane (glycocalyx)

19

Why is the Golgi apparatus important to the maintenance of the glycocalyx?

Complex branching sugars produced in Golgi apparatus important to specific interactions of the glycocalyx.

20

How does enzyme damage to the glycocalyx affect its function?

Alters specificity based interactions of glycocalyx such as:

Adhesion to substrates and other cells
Communication with adjacent cells
Cell mobility
Contact inhibition of movement or division

21

What are the simple mechanisms of control of secretion?

Nervous control
Endocrine control
Neuro-endocrine control
Negative feedback chemical mechanism.

22

Give an example of nervous control of secretion

Sympathetic nervous stimulation of adrenal medullary cells promotes release of adrenalin.

23

Give an example of endocrine control of secretion

Adrenocorticotrophic hormone stimulates the cortex of the of the adrenal gland to release hormones (eg cortisol)

24

Give an example of neuro-endocrine control.

Nervous cells of the hypothalamus control ACTH secretion from the anterior pituitary gland

25

Give an example of negative feedback chemical mechanism

Inhibitory effect of high thyroxine levels on TSH synthesis in the anterior pituitary gland.

26

Mucous membrane line what kind of surface?
Give examples

Surfaces that open to the exterior

Alimentary tract
Respiratory tract
Urinary tract

27

What are the constituents of a mucous membrane (ordered from apical descending)?

Epithelium
Adjacent layer of connective tissue (lamina propria)
Smooth muscle layer (muscularis mucosae)

In addition variable amounts of mucus secreting cells.

28

Describe a serous membrane and where are they found? Give examples.

Thin two part membranes found lining viscera (interior surfaces that don't open to exterior)

Pleural sac
Peritoneal sac
Pericardial sac

29

What is the function of a serous membrane?

Secrete a lubricating fluid which promotes relatively friction free movement of the organs they surround.

30

What are the layers of a serous membrane and each layers function?

Simple squamous epithelium - secretes lubricating fluid

Connective tissue layer - attaches epithelium to adjacent tissues and carries nerves and blood vessels, contains lymphocytes

31

During embryonic development, how does a serous membrane come to surround an organ/s?

Heart lungs and gut develop next to a bag like cavity (serosa) into which they invaginate, hence becoming surrounded by the two layers of the serosa.

32

What are the layers of the alimentary tract?

Mucosa
Muscularis mucosa
Sub mucosa
Muscularis externae
Serosa

33

What is the function of the Muscularis externae in the alimentary tract?

Creates peristaltic waves to move luminal contents along

34

Between what layer of the alimentary tract is the mesentary found?

Between the serous epithelium and connective tissue.

35

In the abdomen what determines whether an organ is covered by serosa or adventitia?

Peritoneal organ - serosa
Retroperitoneal - adventitia

36

What are the stomach rugae?

Folds in the gastric mucosa forming longitudinal ridges in an empty stomach

37

What is secreted by the gastric mucosa?

Acid, gastric enzymes, gastrin (hormone)

38

How many layers does the gastric muscularis externa have?

3
Oblique, circular, longitudinal

39

What are the pilicae circulares of the jejunum?

Circular folds of mucosa and submucosa that project into the lumen

40

What are the layers of the trachea?

(Respiratory) Mucosa
Submucosa
Fibroelastic membrane with trachealis muscle and C-shaped hyaline cartilage
Adventitia

41

What is the function of the epithelium in the colon?

Epithelial cells in the crypts supply mucus and cells to surface

Surface epithelia absorb water and electrolytes.

42

What section of the respiratory system is the conducting portion and what section is the respiratory portion?

Conducting: Trachea to bronchioles

Respiratory: bronchioles to alveoli

43

What are the layers of the bronchi?

Mucosa
Smooth muscle
Submucosa - contains glands
Crescent shaped cartilage (smaller than in trachea)

44

What are the layers of the bronchioles?

Epithelia
Smooth muscle

45

What glands are present in the mucosa of the trachea?

Sero-mucus glands (decreasing closer to bronchioles)

46

What is the function of the c shaped hyaline cartilage?

Prevents tracheal collapse

47

What types of epithelia are found in bronchioles?

Larger bronchioles: simple columnar ciliates

Smaller bronchioles : simple columnar non ciliates

Small sacs extending from wall of terminal bronchioles: simple cuboidal

48

Alveoli are how many cells thick?

1 cell thick

49

What types of cells are found in alveoli?

Type 1 = squamous (90%)
Type 2 = cuboidal (10%)
Macrophages

50

What are the functions of cells of the alveoli?

Squamous epithelia permit gas exchange

Cuboidal epithelia produce surfactant

Macrophages phagocytose inhaled particles.

51

What are the layers of the ureter?

Epithelium
Lamina propria - fibroelastic
Muscularis externa - circular

52

What are the layers of the bladder wall?

Epithelium
Smooth muscle (in the lamina propria)
Muscularis externa (3 interwoven layers)

53

Why is the epithelia of the bladder wall impermeable to urine?

Thick plasma membrane and intercellular tight junctions

54

What are the tissue layers of the urethra?

Epithelium
Lamina propria
Muscularis externa - circular and longitudinal
Adventitia

55

What type of epithelia is found in the urethra and what different type is found in the penile section of the urethra?

Transitional

Stratified columnar

56

Give a list of all types of simple and complex glands.

Simple:
Tubular, alveolar, coiled, branched tubular, branched alveolar

Complex:
Tubular, alveolar, tubuloalveolar