Lecture 5 - Glands

Question 1

Define a gland.

Answer 1

Aggregation of epithelial cells/single epithelial cells which secrete substances.

Question 2

Distinguish between Exocrine and Endocrine.

Answer 2

Endocrine secrete hormones directly into the blood to be taken to distal parts of the body.
Exocrine secrete into location through a duct, mostly enzymes/lubricants.

Question 3

Prolactin - Where, what type, function?

Answer 3

Anterior Pituitary Gland, Endocrine gland, stimulates milk production in mothers breasts.

Question 4

Saliva - Where, what type, function?

Answer 4

Salivary Glands, specifically Buccal Cavity
Exocrine Gland
Digest substances and lubricate

Question 5

Sebum - Where, what type, function?

Answer 5

Sebaceous Gland
Exocrine Gland
On skin/in ear, protect tissue from pathogens

Question 6

Vasopressin (ADH) - Where, what type, function?

Answer 6

Posterior Pituitary Gland
Endocrine Gland
Prevents water loss in kidneys

Question 7

T3, T4 - Where, what type, function?

Answer 7

Thyroid Gland
Endocrine Gland
Control metabolism

Question 8

Calcitonin - Where, what type, function?

Answer 8

Thyroid Gland 
Endocrine Gland
Calcium Homeostasis (works in opposite with Parathyroid Hormone)

Question 9

Sweat - Where, what type, function?

Answer 9

Sweat Glands
Exocrine Gland
Control temperature and excretion

Question 10

Colostrum/milk - Where, what type, function?

Answer 10

Mammary Glands
Exocrine Gland
Responds to Oxytocin and Prolactin, nourishes neonates

Question 11

Somatotrophin - Where, what type, function?

Answer 11

Anterior Pituitary Gland
Endocrine Gland
Regulates growth of body/tissue

Question 12

Oxytocin - Where, what type, function?

Answer 12

Posterior Pituitary Gland
Endocrine Gland
Signals uterus for baby delivery and helps ejection of milk

Question 13

Lachrymal Glands - Where, what type, function?

Answer 13

Eyes
Endocrine Gland
Moistens eyes, also Lysozyme to kill bacteria

Question 14

When are glands generated or begin generating?

Answer 14

During utero development, specifically week 4/5 of gestation

Question 15

Describe/explain Gland Generation

Answer 15

FGF recieved
Proliferation of daughter cells occurs and cells undergo downgrowth into connective tissue
Exocrine: Central cells die to produce duct (canalicularisation)
Endocrine: Produce angiogenic factors that stimulate blood vessel growth (empty vessels)

Question 16

How does branching occur?

Answer 16

Immature fibroblasts release FGF10
Epithelial cells move towards signal
Depending on activated GFs, elongation or branching occurs.

Question 17

Differentiate how elongation and branching occurs.

Answer 17

Elongation: GF1 active, GF2 inactive
Branching: GF1 inactive, GF2 active

Question 18

How does branching/elongation stop?

Answer 18

Shh stops it

Question 19

Name 7 types of shapes for gland ducts with an example of each.

Answer 19

Simple Tubular
Simple Branched Tubular
Simple Alveolar 
Simple Branched Alveolar
Compound Tubular
Compound Alveolar
Compound Tubuloalveolar

Question 20

What two types of cells exist in exocrine glands?

Answer 20

Duct lining cells

Secretory cells

Question 21

How can cells at the end of ducts behave? How does this benefit secretion?

Answer 21

Cells can change morphology into Myoepithelial cells ( cells w/ epithelial and smooth muscle) to help eject secretions.

Question 22

Describe Salivary and Breast Glands (lecture).

Answer 22

Look at lecture.

Question 23

Name the 3 types of secretion.

Answer 23

Merocrine, Holocrine, Apocrine

Question 24

Describe Merocrine

Answer 24

Vesicles fuse with membrane of apex

Eg. Endocrine glands of pancreas

Question 25

Describe Holocrine

Answer 25

Complete loss of cytoplasm as cells die

Eg. Sebaceous glands in skin

Question 26

Describe Apocrine

Answer 26

Partial cytoplasm/cell loss

Eg. sweat glands or mammary glands

Question 27

Describe 2 pathways of merocrine

Answer 27

Regulated Secretion - Secretory products accumulate into granules in vesicles and released by Calcium ion stimulation

Constitutive Secretion - Packaged in small vesicles and continuously released (mainly populates membrane w/ proteins)

Question 28

What is a Cytocrine Gland?

Answer 28

Cells are released as secretion (spermatid in seminiferous tubule)

Question 29

Describe Insulin Secretion.

Answer 29

Beta-cells take in glucose via GLUT-2
This is used for metabolism to produce ATP
ATP binds to K+ channel and closes it
Sulphonylurea receptor hence prevents closure of Ca2+ channel and Ca2+ influx occurs
Leads to insulin secretion

Question 30

Difference between cis and trans golgi apparatus region?

Answer 30

Cis - ER cisternae bind to Golgi at this region and Golgi cisternae are built here.
Golgi modifies proteins in its lumen…
Trans - Vesicles leave the Golgi Apparatus to leave the cell.

Question 31

Glycosylation definition

Answer 31

Covalent attachment of sugars by enzymes to proteins and lipids (glycoproteins and glycolipids)

Question 32

Phagocytosis vs Pinocytosis

Answer 32

Process where phagocytes (cells) envelope or engulf other cells/particles (macrophages, dendritic cells, neutrophils etc.)
Process which liquid droplets are ingested by cells (all cells, ESP smooth muscle)

Question 33

Transcytosis has 4 methods which are…

Answer 33

1) Via aqueous channels in intracellular junctions (Amino acids for hormone production)
2) Lipid cell membranes (Steroid hormones)
3) Carrier proteins *thyroxine transport across thyroid cell)
4) Endocytosis via surface receptors then extcytosis (cholesterol transport)

Question 34

How are gland secretions controlled?

Answer 34

Via negative feedback primarily.
3 types - Humoral (negative feedback), Neural (negative feedback), and hormonal (hormones secreted to stimulate other glands to secrete hormones)