TOB S2 - Glands and Internal surfaces of the body

Question 1

Define a gland.

Answer 1

A collection of epithelial cells specialised for secretion.

Question 2

List the ways in which glands are classified.

Answer 2

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

Question 3

How are glands classified by secretion destination?

Answer 3

Exocrine glands secrete into ducts or onto surfaces

Endocrine glands are ductless, secrete directly into blood

Question 4

How are the secretory portion of glands classified by structure?

Answer 4

Uni/multicellular

Question 5

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

Answer 5

Alveolar, tubular, coiled, branched

Question 6

What are the different types of ducts present in glands?

Answer 6

Simple

Complex (branched)

Question 7

How are glands classified by nature of secretion?

Answer 7

Mucous or serous

Question 8

Describe mucous secretion.

How does it react to H&E staining?

Answer 8

Contains mucus rich in mucin (glcosylated polypeptides)

Stains poorly with H&E stain

Question 9

Describe serous secretions

How does it react to H&E staining?

Answer 9

Watery, no mucus, enzymes present

Stains pink with H&E stain

Question 10

What are the three methods of secretion?

Answer 10

Merocrine, Apocrine, Holocrine

Question 11

Describe the process of merocrine secretion

Answer 11

Membrane bound vesicle fuses with plasma membrane

Contents released into intracellular space

Additional area of plasma membrane recovered

Question 12

Describe the process of Holocrine secretion.

Answer 12

Disintegration of whole cell releases all cellular contents

Question 13

Describe the process of Apocrine secretion

Answer 13

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.

Question 14

What is endocytosis?

Answer 14

The opposite process to exocytosis (merocrine secretion)

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

Question 15

Describe transepithelial transport

Answer 15

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)

Question 16

Describe the structure of the Golgi apparatus

Answer 16

Layers of disk shaped cisternae

Flattened on one side, concave on the other

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

Question 17

Describe the functions of the Golgi apparatus

Answer 17

Sorting and packaging of contents into vesicles

Glycosylation of proteins and lipids

Transport

Question 18

Where do vesicles from the Golgi apparatus end up?

Answer 18

Majority exocytosed

Some retained (eg lysosomes)

Some enter plasma membrane (glycocalyx)

Question 19

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

Answer 19

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

Question 20

How does enzyme damage to the glycocalyx affect its function?

Answer 20

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

Question 21

What are the simple mechanisms of control of secretion?

Answer 21

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

Question 22

Give an example of nervous control of secretion

Answer 22

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

Question 23

Give an example of endocrine control of secretion

Answer 23

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

Question 24

Give an example of neuro-endocrine control.

Answer 24

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

Question 25

Give an example of negative feedback chemical mechanism

Answer 25

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

Question 26

Mucous membrane line what kind of surface? | Give examples

Answer 26

Surfaces that open to the exterior Alimentary tract Respiratory tract Urinary tract

Question 27

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

Answer 27

Epithelium Adjacent layer of connective tissue (lamina propria) Smooth muscle layer (muscularis mucosae) In addition variable amounts of mucus secreting cells.

Question 28

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

Answer 28

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

Question 29

What is the function of a serous membrane?

Answer 29

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

Question 30

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

Answer 30

Simple squamous epithelium - secretes lubricating fluid Connective tissue layer - attaches epithelium to adjacent tissues and carries nerves and blood vessels, contains lymphocytes

Question 31

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

Answer 31

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.

Question 32

What are the layers of the alimentary tract?

Answer 32

``` Mucosa Muscularis mucosa Sub mucosa Muscularis externae Serosa ```

Question 33

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

Answer 33

Creates peristaltic waves to move luminal contents along

Question 34

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

Answer 34

Between the serous epithelium and connective tissue.

Question 35

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

Answer 35

Peritoneal organ - serosa | Retroperitoneal - adventitia

Question 36

What are the stomach rugae?

Answer 36

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

Question 37

What is secreted by the gastric mucosa?

Answer 37

Acid, gastric enzymes, gastrin (hormone)

Question 38

How many layers does the gastric muscularis externa have?

Answer 38

3 | Oblique, circular, longitudinal

Question 39

What are the pilicae circulares of the jejunum?

Answer 39

Circular folds of mucosa and submucosa that project into the lumen

Question 40

What are the layers of the trachea?

Answer 40

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

Question 41

What is the function of the epithelium in the colon?

Answer 41

Epithelial cells in the crypts supply mucus and cells to surface Surface epithelia absorb water and electrolytes.

Question 42

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

Answer 42

Conducting: Trachea to bronchioles Respiratory: bronchioles to alveoli

Question 43

What are the layers of the bronchi?

Answer 43

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

Question 44

What are the layers of the bronchioles?

Answer 44

Epithelia | Smooth muscle

Question 45

What glands are present in the mucosa of the trachea?

Answer 45

Sero-mucus glands (decreasing closer to bronchioles)

Question 46

What is the function of the c shaped hyaline cartilage?

Answer 46

Prevents tracheal collapse

Question 47

What types of epithelia are found in bronchioles?

Answer 47

Larger bronchioles: simple columnar ciliates Smaller bronchioles : simple columnar non ciliates Small sacs extending from wall of terminal bronchioles: simple cuboidal

Question 48

Alveoli are how many cells thick?

Answer 48

1 cell thick

Question 49

What types of cells are found in alveoli?

Answer 49

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

Question 50

What are the functions of cells of the alveoli?

Answer 50

Squamous epithelia permit gas exchange Cuboidal epithelia produce surfactant Macrophages phagocytose inhaled particles.

Question 51

What are the layers of the ureter?

Answer 51

Epithelium Lamina propria - fibroelastic Muscularis externa - circular

Question 52

What are the layers of the bladder wall?

Answer 52

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

Question 53

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

Answer 53

Thick plasma membrane and intercellular tight junctions

Question 54

What are the tissue layers of the urethra?

Answer 54

Epithelium Lamina propria Muscularis externa - circular and longitudinal Adventitia

Question 55

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

Answer 55

Transitional Stratified columnar

Question 56

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

Answer 56

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