Energy Metabolism

Question 1

Define energy (fuel) metabolism. Name the 3 energy fuels

Answer 1

Process of storage & utilisation of fuels.

Glucose, amino acids, fatty acids

Question 2

Biomolecules in excess are?

Answer 2

energy storage molecules

Question 3

What is glycogen?

Answer 3

main storage form of glucose

Question 4

What is metabolic rate? How is it measured?

Answer 4

the speed at which we use energy.
“Rate at which E is expended during internal & external work”.
Measured kilojoules/hour

Question 5

Whats factors influence metabolic rate?

Answer 5

age, gender, muscular activity, size (SA), environmental temp.

Question 6

What is basal metabolic rate?

Answer 6

animal’s RESTING metabolic rate

Question 7

As mass increases…?

Answer 7

MR increases

Question 8

Name the 3 possible states of energy balance (EB) & explain

Answer 8

1. Neutral EB (energy input=output)
2. Positive EB (energy input>output) =>gaining weight
3. Negative EB (energy input losing weight

Question 9

Seasonal fluctuating of EB in animals is good. Why?

Answer 9

Alternating seasons of good/bad food quantity/quality ensures energy reserves are mobilised. Essential part of long-term feeding strategy (hibernation)

Question 10

What is glycogenesis?

Answer 10

Breakdown of glucose to glycogen

Question 11

What is glycogenolysis?

Answer 11

glycogen=>glucose

Question 12

What is gluconeogenesis?

Answer 12

amino acids/lactic acids=>glucose

Question 13

What is protein synthesis?

Answer 13

amino acids=>protein

Question 14

What is protein degredation?

Answer 14

protein=>amino acids

Question 15

What is lipogenesis?

Answer 15

(synthesis)

fatty acids & glycerol=> triglycerides (fat)

Question 16

What is lipolysis?

Answer 16

triglycerides (fat)=> fatty acids & glycerol

Question 17

Name the endocrine portion of the pancreas

Answer 17

pancreatic islets

Question 18

Name the 4 cell types found in pancreatic islets and what they secrete

Answer 18

Alpha -secrete glucagon
Beta -secrete insulin
Delta -somatostatin
F cells -pancreatic polypeptide (not a hormone)

Question 19

What is the principle action of glucagon?

Answer 19

to increase blood glucose concentration when it falls below normal

Question 20

What is the principle action of insulin?

Answer 20

helps lower blood glucose concentration when it is too high

Question 21

What does blood glucose concentration control?

Answer 21

secretion of glucagon & insulin via - feedback

Question 22

Explain the physiology of low blood glucose concentration

Answer 22

Low [BG] stimulates secretion of glucagon.
Gluca. acts on liver cells to speed up conversion of glycogen to glucose (glycogenolysis), & to promote formation of glucose from lactic acid (gluconeogenesis).
As result, liver cells release glucose into blood more rapidly [] ^

Question 23

Explain the physiology of high BG concentration

Answer 23

High [BG] stimulates secretion of insulin.
Insulin:
speeds up facilitated diff. of glucose into cells
increase glycogenesis
increase lipogenesis
slow glycogenolysis
slow gluconeogenesis

.’. [BG] decreases

Question 24

Anterior pituitary secretes

Answer 24

hormones (GH) that regulate a wide range of bodily activities, from growth to repro.

Question 25

The anterior pituitary cells, somatotrophs, secrete …? thyrotrophs secrete…?

Answer 25

soma- Growth Hormone (GH) aka somatotropin

thyro -thyroid-stimulating hormone (TSH)

Question 26

What does GH stimulate?

Answer 26

secretion of insulin-like growth factors (IGF’s), hormones that stimulate general body growth & regulate aspects of metabolism

Question 27

GH (somatotropin) production is regulated by?

Answer 27

GH releasing hormone (GHRH)

GH inhibiting hormone (GHIH)

Question 28

Hypoglycaemia (low blood sugar) stimulates?

Answer 28

hypothalamus to secrete GHRH=>reaches pituitary stimulates somatotrophs to release GH=>GH stimulates secretion of IGF, which speed up glycogenolysis=>glucose enters blood more rapidly, raising BS.

Question 29

Hyperglycaemia (high BS) stimulates?

Answer 29

hypothalamus to secrete GHIH=>reaches pituitary & inhibits secretion of GH by somatotrophs=>low [] of GH & IGF’s slows glycogenolysis=>glucose enters blood more slowly, lowering BS.

Question 30

Follicular cells in thyroid gland produce which two hormones? And is the only gland that does what?

Answer 30

Thyroxine (T4)
Triiodothyronine (T3)
only endocrine gland that stores its secretory products in large quantities.

Question 31

Two basic ingredients for thyroid hormone synthesis

Answer 31

Tyrosine & iodine

Question 32

A bit about conversion of T4 to T3

Answer 32

90% of secretion in mammals is T4

Most T4 is stored, then activated & converted to T3 (80%)

Question 33

Primary action of thyroid hormones (T3 & T4) is?

Answer 33

to increase basal metabolic rate
increase fat & carbohydrate metabolism (glycolysis, glycogenolysis, lipolysis)
increase number/activity of mitochondria

Question 34

Adrenal glands produce?

Answer 34

catecholamines (adrenaline & noradrenaline)

Question 35

what are the biological effects of catecholamines

Answer 35

increased HR, Bp
Dilation of pupils, airways, blood vessels
increased gluconeogenesis, glycogenolysis, cellular O2 consumption

Question 36

Describe what a tertiary endocrine disorder is

Answer 36

problem originates in hypothalamus

Question 37

describe what a secondary endocrine disorder is

Answer 37

initial disorder is in pituitary gland

Question 38

describe what a primary endocrine disorder is

Answer 38

the specific endocrine gland is dysfunctional