[8] Endocrine Tissues

Question 1

Name 2 hormones released by the hypothalamus

Answer 1

Vasopressin (ADH) and oxytocin
- both travel to the posterior pituitary through nerves

Question 2

How is the pituitary divided?

Answer 2

Into 2 lobes: anterior pituitary and posterior pituitary

Question 3

Name 2 hormones secreted by the thyroid gland

Answer 3

T3 and T4

Question 4

Where are the thyroid glands found?

Answer 4

In the neck, just below the larynx

Question 5

What are parafollicular cells?

Answer 5

Cells within the thyroid that produce calcitonin independent of thyroid hormone synthesis

Question 6

What is the role of parafollicular cells?

Answer 6

Monitor plasma calcium concentrations and decrease Ca2+ levels (counteracts function of PTH)

Question 7

What is the major effect of calcitonin?

Answer 7

Inhibits osteoclast activity in bone

Question 8

Name the minor effect of calcitonin

Answer 8

Inhibits renal calcium and phosphate re-absorption in the tubular cells -> more calcium and phosphate excreted

Question 9

Name a function of the parathyroid gland

Answer 9

Constantly monitors plasma calcium concentration

Question 10

Where are the adrenal glands found?

Answer 10

Superior pole of kidneys (just above the kidneys)

Question 11

Name the 3 layers of the adrenal cortex

Answer 11

• Outer - Zona glomerulosa; aldosterone regulates BP
• Middle - Zona fasiculata; glucocorticoids (cortisone/cortisol) mobilises fats, proteins and carbohydrates
• Inner - Zona reticularis; androgen precursors i.e. androstenedione, DHEA, etc.

Question 12

Define stress

Answer 12

Maintenance of homeostasis in the presence of aversive stimuli that requires activation of a complex range of responses involving the endocrine, nervous and immune systems, is collectively known as the stress response.
Behavioural changes - increased awareness, improved cognition, euphoria, enhanced analgesia
Physiological adaptations - increased cardiovascular tone, increased BR, increased intermediate metabolism, decreased vegetative functions

Question 13

Where are the principal effectors of stress response localised?

Answer 13

Hypothalamus
Anterior lobe of pituitary gland
Adrenal glands

Question 14

Where are the parathyroid glands located?

Answer 14

Oh the posterior wall of the thyroid

Question 15

What are the 2 cell types in the parathyroid glands? What is their function?

Answer 15

Chief/principal cells - produce PTH
Oxyphil cells - function unknown

Question 16

What is the function of PTH?

Answer 16

Stimulates osteoclast resorption of bone and reduces calcium loss in urine. Promotes calcium uptake by gut.