Nutrition - Hormonal Control

Question 1

what is the absorptive state

Answer 1

the time during and right after eating a meal

Question 2

how long does the absorptive state last

Answer 2

four to six hours

Question 3

where does glucose go in the absorptive state

Answer 3

storage of energy
intestine
adipose tissue
liver glycogen
muscle glycogen

Question 4

what is the upper limit of glycogen in the body

Answer 4

around 1050 g

Question 5

what is the fate of glucose in the post prandial state (this is the same as the absorptive state)

Answer 5

contribution to energy metabolism
goes to brain, muscle for ATP production and the liver

Question 6

what is the post absorptive state

Answer 6

period when the gastrointestinal tract is empty and energy comes from the breakdown of our body’s reserves

Question 7

when does glucose release from the liver increase

Answer 7

during the post absorptive state

Question 8

what is the role of increased lipolysis in sparing glucose

Answer 8

freefatty acids are oxidised to cover energy demands of muscles and other tissues
free fatty acids are used for the synthesis of ketone bodies and glycerol

Question 9

what are FFA

Answer 9

free fatty acids

Question 10

describe metabolism in the post absorptive state

Answer 10

directed to blood glucose levels
first available store of glucose is in the livers store of glycogen

Question 11

describe gluconeogenesis

Answer 11

activated in the liver and glucose is synthesised from lactate, pyruvate, glycerol and amino acids

Question 12

describe the metabolic and hormonal responses in the post absorptive state

Answer 12

decreased blood glucose
decreased blood triglycerides
increased blood free fatty acids
increased blood beta hydroxybutyrate

Question 13

what directs all of the events that occur in the post absorptive state

Answer 13

insulin

Question 14

describe what insulin does in the absorptive state

Answer 14

glucose uptake by muscle
suppression of FFA release from adipose tissue
FFA release from chylomicrons
liver and muscle glycogen synthesis
protein synthesis

Question 15

what are the effects of insulin on carbohydrate metabolism

Answer 15

stimulate glucose uptake by cells
stimulate glycolyses
stimulate glycogen synthesis
inhibit glycogen catabolism

Question 16

what catalyses fat mobilisation

Answer 16

hormone sensitive lipase

Question 17

what deactivates hormone sensitive lipase

Answer 17

dephosphorylation in response to high concentrations of insulin

Question 18

summarise the link between insulin and protein synthesis

Answer 18

general anabolic role
marked loss of protein from the body if there is insulin deficiency
growth hormone can also stimulate protein synthesis and act through insulin like growth factors

Question 19

what are the roles of insulin in protein synthesis

Answer 19

increased uptake of amino acids
increased activity of protein synthesis enzymes
reduced activity of protein catabolic enzymes

Question 20

what stimulates insulin release

Answer 20

increased blood glucose
increased amino acid levels in the plasma
neural stimulation of the pancreas
gut hormones

Question 21

what decreases insulin release

Answer 21

reduction in blood glucose
sympathetic neural stimulation

Question 22

describe the role of glucagon in the regulation of metabolim during post absorptive state

Answer 22

released by alpha cells of islets of langerhans
increased glycogen breakdown in the liver
increased lipolysis
increased gluconeogenesis in the liver
increased keton body synthesis

Question 23

what characterises the metabolic response to starvation

Answer 23

a switch from carbohydrate metabolism to fat metabolism
liver and muscle glycogen stores are depleted
ketogenesis takes over and much of the body’s metabolic needs are met by ketone bodies and free fatty acids

Question 24

what can severe negative energy balances lead to

Answer 24

decline in metabolism
decreased bone mass
reduction in thyroid hormone
reduction in testosterone levels
inability to concentrate
reduction in physical performance

Question 25

what are the consequences of positive energy imbalances

Answer 25

plaque build up in arteries blood pressure increases LDL cholesterol and TAG increases insulin resistance develops which leads to development of type 2 diabetes risk for certain cancers increases

Question 26

what do white adipocytes secrete

Answer 26

cytokines growth factors regulators of lipid metabolism hormones acute inflammatin proteins complement factors chemokine regulators of glucose metabolism

Question 27

what is activated during stress in relation to energy balance

Answer 27

hypothalmic pituitary adrenal axis, which regulates many body processes, including energy storage and expenditure

Question 28

describe the role of cortisol in control of nutrient metabolism during stress

Answer 28

- regain glucose homeostasis, increase blood glucose through gluconeogenesis - plays an important role in glycogenesis in the liver and muscle tissue by facilitation of the activation of glycogen phosphorylase - redistributes glucose to areas of the body that need it the most and away from the digestive and reproductive organs

Question 29

what is the role of adrenaline and noradrenaline in control of nutrient metabolism during stress

Answer 29

- provide an increase in fatty acids required for energy production - by triggering an intracellular secondary messenger cascade that phosphorylates hormone sensitive lipase to break down TAG of adipose and muscle tissue into glycerol and free fatty acids - also increases glucose

Question 30

how does adrenalin increase glucose required for energy production during stress

Answer 30

inhibit insulin secretion by the pancreas trigger glucagon secretion in the pancreas stimulate glycogenolysis in the liver and the muscle stimulate glycolysis in the muscle

Question 31

describe the role of growth hormone in control of nutrient metabolism during stress

Answer 31

promote lipolysis and fatty acid oxidation reduce liver uptake of glucose and help to maintain plasma glucose concentration promote gluconeogenesis in the liver

Question 32

describe the hormonal responses to surgery

Answer 32

anterior pituitary ACTH increases growth hormone increases adrenal cortex cortisol increases aldosterone increases insulin decreases glucagon usuallly small increases thyroid thyroxine decreases

Question 33

what is the overall metabolic effect of hormonal changes during surgery

Answer 33

increased catabolism which mobilises substrates to provide energy sources and a mechanism to retain salt and water and maintain fluid volume and cardiovascular homeostasis

Question 34

what is the hormonal response to intravenous sedation

Answer 34

plasma growth hormone and prolactin increase changes in cardiovascular like increased heart rate to indicate a stress response

Question 35

does local analgesia lead to more or less of a stress response than general anaesthesia for oral surgery

Answer 35

less patient stress association