The Endocrine System (part 3)

Question 1

state 2 functional facts about the Posterior Pituitary Gland

Answer 1

1. does not synthesise hormones, only secretes them

2. secretes neuropeptides synthesised in the hypothalamus

Question 2

state 2 hormones the Posterior Pituitary Gland secretes, and their functions

Answer 2

1. Oxytocin - involved in milk ejection reflex of nursing mothers and emotional bonding
2. Vasopressin/ADH - involved in the regulation of water balance and osmolarity

Question 3

what is growth determined by?

Answer 3

growth is genetically determined, but environmental factors can influence growth (eg - nutrition, vitamins, minerals, exercise)

Question 4

state 3 examples of hormones that play an important role in growth

Answer 4

1. Growth hormone (GH) and Insulin-like growth factor 1 (IGF-1)
2. thyroid hormones
3. insulin
4. sex hormones (testosterone + oestrogen)
5. cortisol

Question 5

state 3 functions of Growth Hormone (GH)

Answer 5

1. secretion stimulated by exercise and this stimulates muscle release of IGF-1
2. affects bone, muscle, adipose and liver growth and function
3. stimulates protein synthesis
4. major stimulus of post-natal growth
5. stimulates the liver to produce IGF-1

Question 6

exercise is a major stimulus of GH secretion. state 2 facts facts to expand on this statement

Answer 6

1. different types of exercise will induce different GH responses
2. responses are higher in younger individuals compared to early middle aged men

Question 7

state what 3 places that GH effects during exercise

Answer 7

1. Gluconeogenesis (liver)
2. adipose tissue
3. tissues

Question 8

explain the effect GH has on gluconeogenesis during exercise (2 things)

Answer 8

1. positive effect

2. increases rate of gluconeogenesis (non-carbohydrate sources –> glucose)

Question 9

explain the effect GH has on adipose tissue during exercise (2 things)

Answer 9

1. positive effect

2. triglyceride breakdown –> FFA + glycerol

Question 10

explain the effect GH has on tissues during exercise (2 things)

Answer 10

1. negative effect

2. blocks entry of glucose into tissue and increases FFA oxidation in the tissue

Question 11

state the 2 main hormones used in response to stress, and where they are secreted from

Answer 11

1. cortisol - adrenal cortex

2. epinephrine - adrenal medulla

Question 12

explain the 8 step response to stress

Answer 12

1. neural input
2. hypothalamus inc^ corticotropin-releasing hormone (CRH)
3. inc^ plasma CHR (in hypothalamus-pituitary portal vessels)
4. anterior pituitary inc^ adrenocorticotropic hormone (ACTH)
5. inc^ plasma ACTH
6. adrenal cortex inc^ cortisol secretion
7. inc^ plasma cortisol
8. target cells for cortisol response due to inc^ cortisol

Question 13

state 3 physiological functions of cortisol - responses to chronic stress

Answer 13

1. permits epinephrine/norepinephrine action on muscles + blood vessels
2. promotes glucose synthesis in liver during LT fasting or exercising
3. maintaining cellular conc^ of metabolic enzymes required to produce glucose + fatty acids between meals
4. dec^ events associated with inflammatory response such as capillary permeability and production of prostaglandins

Question 14

cortisol and exercise - state 1 fact about it

Answer 14

cortisol is a catabolic hormone, therefore will act in synergy with other hormones to increase the supply of energy to the working muscles

Question 15

what is the fast response to stress?

Answer 15

catecholamine secretion - the fast response to stress

Question 16

explain the effects of ‘catecholamine secretion’ as the fast response to stress (4 facts)

Answer 16

1. inc^ availability of energy (glucose/lipids) in the blood
2. inc^ Hr, breathing frequency, + cell metabolism
3. dilation of major blood vessels and constriction of peripheral capillaries
4. pupil dilation

Question 17

what percentage of catecholamine secreted by the adrenal medulla is epinephrine?

Answer 17

80% of the catecholamine secreted from the adrenal medulla is epinephrine

Question 18

what is norepinephrine? and where is it usually released from?

Answer 18

1. norepinephrine is a precursor of epinephrine, but is also a hormone in it’s own right
2. released mainly by the adrenergic neurons in the sympathetic nervous system

Question 19

what do both epinephrine and norepinephrine bind to?

Answer 19

both bind to alpha/beta-adrenergic receptors at cell membranes. the receptor type will determine the response

Question 20

state the 2 main effects of norepinephrine

Answer 20

1. inc^ HR + BP (beta 1)

2. peripheral vasoconstriction (alpha 1)

Question 21

state the 5 main effects of epinephrine

Answer 21

1. inc^ HR + BP (beta 1)
2. peripheral vasoconstriction (alpha 1)
3. inc^ lipid breakdown (beta 2)
4. coronary dialation, bronchial dialation (beta 2)
5. glycogenolysis (beta 2)

Question 22

state and explain the 2 functions of the pancreas

Answer 22

1. exocrine - secretion of pancreatic enzymes for food digestion in the duodenum
2. endocrine - secretion of insulin and glucagon

Question 23

the endocrine function of the pancreas is accomplished by the islets if Langerhans. state the 5 cell types as well as their proportions

Answer 23

1. alpha cells - 10%
2. beta cells - 80%
3. delta cells - 3-5%
4. pancreatic polypeptide cells (F/PPC) - <2%
5. epsilon cells - <1%

Question 24

state 2 functions of insulin

Answer 24

1. inc^ glucose uptake + storage in adipose (lipogenesis) and muscle tissues (glycogenesis)
2. inc^ glucose uptake + storage (glycogen) by liver and dec^ hepatic glucose production
3. inc^ amino acid uptake and protein synthesis
4. dec^ triglyceride breakdown (lipolysis) in adipose tissue

Question 25

state 2 functions of glucagon

Answer 25

1. raises conc^ of glucose in the blood by promoting glycogenolysis (glycogen breakdown) 2. stimulate gluconeogenesis - the production of glucose form amino acids and glycerol in the liver

Question 26

state the names of the two main insulin sensitive peripheral tissues

Answer 26

1. skeletal muscle | 2. adipose tissue

Question 27

what does glucagon mainly act upon

Answer 27

the liver

Question 28

state the 4 step pathway of how insulin works to counteract raising blood glucose levels away from homeostasis

Answer 28

1. high blood glucose conc^ detected by insulin releasing cells in the pancreas 2. insulin releasing cells of pancreas stimulated to release insulin into the blood stream 3. most body cells take up more glucose 4. blood glucose levels decline to a set point; stimulus for insulin secretion diminishes and body returns to homeostasis

Question 29

state the 4 step pathway of how glucagon works to counteract decreasing blood glucose levels away from homeostasis

Answer 29

1. low blood glucose levels detected by glucagon-releasing cells of the pancreas 2. glucagon-releasing cells of pancreas stimulated to release glucagon into the blood; targets liver 3. liver breaks down glycogen stores into glucose and releases into blood stream 4. blood glucose levels rise to a set point; stimulus for glucagon release diminishes as body returns to homeostasis

Question 30

state what it is meant by the key term - glycogenolysis

Answer 30

glycogenolysis is the breakdown of glycogen into glucose

Question 31

state what it is meant by the key term - gluconeogenesis

Answer 31

gluconeogenesis is the metabolic process by which organisms produce sugars for catabolic reactions from non-carbohydrate sources

Question 32

state what it is meant by the key term - glycogenesis

Answer 32

glycogenesis is the formation of glycogen from sugars

Question 33

state 2 facts about type 1 diabetes

Answer 33

1. caused by destruction of beta cells on the pancreas | 2. no insulin is secreted

Question 34

state 4 facts about type 2 diabetes

Answer 34

1. environmental factors caused it 2. obesity a risk factor of type 2 diabetes 3. insulin secretion is normal, but it's action is impaired 4. adipose and muscle cells do not respond to the action of insulin (insulin resistance)