Endocrine System II/III

Question 1

What is another name for a growth hormone?

Answer 1

Somatotrophic hormone

Question 2

What are all the anterior pituitary gland hormones released from?

Answer 2

All peptides - Interact with many plasma membrane receptors, regulates secretion of growth hormones

Question 3

Describe growth hormones

Answer 3

Don’t target specific glands, but mainly the liver
Stimulates IGF-1 production (inc anabolic)
Opposes insulin
Inc fatty acids utility

Question 4

What is the secretion of GH stimulated and inhibited by?

Answer 4

Stimulated by GHRH
Inhibited by SS from hypothalamus
Note: SS blocks GHRH stimulation non-competitively

Question 5

Describe GH secretion and regulation

Answer 5

Synthesis increased by thyroid/cortisol hormone
Stimulated by lower glucose levels, free fatty acids, higher AA levels
Stimulated by REM phase, exercise, stress
Daily/Life-time secretion pattern

Question 6

What does the daily pattern of GH secretion show?

Answer 6

Shows Gh stimulated and circulating during night hours

Question 7

What does the life-time pattern of GH secretion show?

Answer 7

Shows that the highest mean circulating conc of GH is during puberty so needed most during this time (Growth)
It also never reaches 0 even in old age so the body can function and repair cells

Question 8

Describe the distribution of GH across the body

Answer 8

In hypo, GHRH inc secretion of GH but GHIH dec by inhibition
GH mainly acts on liver but acts over body to many cells
For energy/growth

Question 9

Describe the purpose of the short negative feedback loop

Answer 9

From anterior to hypo
Too much GH secreted so hypothalamus sent signals to reduce release by GH receptors which senses the conc of GH in circulation

Question 10

Describe the long negative feedback loop

Answer 10

From liver to anterior/hypo
Circulation of GH from body to brain with further distance, goes to both anterior/hypo so both places have insulin-like receptors

Question 11

Describe the distribution of GH across the entire body in terms of increase and decreases

Answer 11

Hypo - GHRH inc, GHIH dec
Anterior - GH inc
Liver - Insulin-like growth factor secretion inc > Many tissues - Cell division
Many tissues - Protein synthesis inc > Energy
Adipose tissue - Glucose uptake dec, Lipolysis inc > Energy
Muscle - Glucose uptake dec, AA uptake inc > Energy

Question 12

Describe the location of thyroid glands

Answer 12

Lies on either side of trachea

Question 13

What 3 hormones do thyroid glands produce

Answer 13

T4, T3, Calcitonin - Regulation of [Ca2+]

Thyroid hormones - T4 and T3 together

Question 14

Describe the T3 and T4 hormones

Answer 14

T4 - Major product, function as prohormone

T3 - Secreted less, derived from T4 but provides all thyroid activity

Question 15

Describe the effects of thyroid hormone

Answer 15

Regulating body’s overall level of cellular metabolic activity/energy release

Question 16

Name some cellular metabolic activity regulated by thyroid hormones

Answer 16

Foetal development, metabolic rate, body temp, cardiac rate, peripheral vasodilation

Question 17

Describe the binding of T3

Answer 17

Binds to nuclear receptor, interacting with DNA to alter gene transcription

Question 18

Describe the effect of T3 on GH synthesis

Answer 18

Increase in nuclear content of mRNA transcript of GH gene, direct synthesis of GH increases

Question 19

Describe disorder in terms of hypothyroidism

Answer 19

Deficiency in T3/T4 secretion, due to autoimmune/lack of iodide diet
Symptoms - Low metabolic rate, lethargy, bradycardia, increased weight gain

Question 20

Describe disorder in terms of hyperthyroidism

Answer 20

Over production of endogenous H/ingestion of exogenous H

Symptoms - High metabolic rate, restless, tachycardia, heat intolerance, weight loss

Question 21

Describe the pancreas

Answer 21

Found behind the stomach, attached to duodenum
Made up Islets of Langerhans > a-cells, b-cells, delta-cell (secrete somatostatin), exocrine pancreas (acinar/duct cells secrete enzymes/fluid into digestive track)

Question 22

Describe the synthesis and secretion of Islet hormones

Answer 22

All are peptide hormones

Question 23

Describe the action of Islet hormones

Answer 23

Glucagon - Breakdown of glycogen and increase blood sugar levels
Insulin - Increase glucose uptake, reduces blood sugar levels
SS - Inhibits insulin, secretes glucagon

Question 24

Describe the insulin function mechanism

Answer 24

Binds to receptors in plasma membrane - Causes autophosphorylation of receptor
in/activation of many enzymes - Shifts glucose metabolism to glycogen/pyruvate
Moving GLUT4 to plasma membrane
Facilitated transport of AA, K, Mg into cell
Synthesis/Suppress of many enzymes to regulate cell growth

Question 25

Describe the location of adrenal glands

Answer 25

Above each gland, made up of cortex and steroid hormones

Question 26

Describe the location of adrenal glands

Answer 26

Above each gland, made up of cortex with steroid hormones and medulla

Question 27

Describe the steroid hormones in the cortex of the adrenal glands

Answer 27

Corticosteroids - Glucocorticoids (cortisol, coricosterone), mineralocorticoids (aldosterone) Androgens (sex hormones)

Question 28

Describe the composition of the medulla of the adrenal glands

Answer 28

Made up of: | Catecholamine H, Adrenaline (epinephrine), Noradrenaline (norepinephrine), Dopamine

Question 29

Describe the adrenal medulla

Answer 29

Develops from outgrowth of nervous tissue, surrounded by adrenal cortex, cell bodies don't axons but release their secretes into blood Functionally part of the SNS

Question 30

Describe the function of the adrenal medulla

Answer 30

Stimulation of SNS and hormone secretion as stimulus continues, without this body is less able to face danger/stress

Question 31

Describe catecholamine H

Answer 31

Effects metabolism: Inc metabolism rate, glucagon secretion, diet induced Dec insulin secretion, glucose usage

Question 32

Describe the adrenal cortex

Answer 32

Glucocorticoids - Inc metabolism, dec immune system Mineralocorticoids - regulate fluid/electrolyte balance, reabs of Na instead of K/H, H2O reabs increasing blood volume Androgens -

Question 33

Describe the action of glucocorticoids

Answer 33

Derived from cholesterol, released in response to CRH/ACTH | Used as drugs - Dec inflammatroy/immune responses eg for skin conditions, autoimmune disease

Question 34

Describe the action of aldosterone

Answer 34

Effects salt balance, mainly kidney tubules Promotes Na/H2O retention Increases K excretion

Question 35

Describe Addison's disease

Answer 35

Adrenal insufficieny, not enough steroid hormones produced Dec mineralocorticoids causes hypotension, dehydration, electrolyte imbalance - Cardiac issues Dec glucocorticoids causes inability to maintain normal glucose conc, dec basal metabolic rate so mild infection may cause death Inc ACTH release due to negative feedback causes skin blotchy