Fate of Nutrients: hormonal control

Question 1

how long does the absorptive state last for during and after each meal?

Answer 1

4 to 6 hours

Question 2

what is the absorptive (postprandial) state?

Answer 2

time during and after eating a meal

Question 3

what happens in the postprandial state?

Answer 3

end product of nutrient digestion undergo anabolic processes leading to nutrient storage in format of glycogen and TAG and contribute to energy production and undergo oxidative disposal

Question 4

in the postpranial state what are most dietary amino acids used for?

Answer 4

protein synthesis

Question 5

what is the postabsorptive state?

Answer 5

period when the GIT is empty and energy comes from the breakdown of our body reserves
- rate of glucose release from the liver is increases
- lipolysis of TG in adipose tissue is increases

Question 6

what is the role of increased lipolysis in sparing glucose?

Answer 6

FFA are oxidised to cover energy demands of muscle and other tissues
FFA are used for synthesis of ketone bodies and glycerol us substance for gluconeogeness

Question 7

what is metabolism in the post absorptive state like?

Answer 7

directed to maintain blood glucose levels

Question 8

in the postabsorptive state what is the first available store of glucose?
how long can these stores maintain blood sugar levels?

Answer 8

livers store of glycogen
3 hours

Question 9

what is the process of guconeogenesis?

Answer 9

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

Question 10

what are the metabolic and hormonal responses in the absorptive state?

Answer 10

• increased glucose
• increased TG
• decreased blood NEFA
• decreased B-hydroxybutyrate

*increased insulin
*decreased glucagon

Question 11

what are the metabolic and hormonal responses in the postabsorptive state?

Answer 11

• decreases glucose
• decreased TG
• increased blood NEFA
• increased B-hydroxybutyrate

*decreased insulin
*increased glucagon

Question 12

what is the role of insulin in regulation and metabolism during absorptive state?

Answer 12

essentially all of the events that occur in the absorptive state are directed by insulin

Question 13

what is the effect of insulin on CHO metabolism?

Answer 13

-stimulates glucose uptake by cells
- stimulates glycolyses
- stimulates glycogen synthesis
- inhibits glycogen catabolism

Question 14

what is fat mobilisation catalysed by?

Answer 14

enzyme = hormone sensitive lipase (HSL)

Question 15

how and when is hormone sensitive lipase inactive?

Answer 15

when insulin levels are high
by dephospho rylation in response to high concentration of insulin

Question 16

what impact does insulin have on the process of re-esterification?

Answer 16

insulin stimulates process of re-esterification (synthesis of TAG) by provision of glycerol-3 phosphate

Question 17

how does insulin have an effect on the clearance of chylomicrons and VLDL?

Answer 17

• increases the activity of lipoprotein lipase (LPL) activity in adipose tissue
• LPL resides son the capillary endothelium of adipose and muscle tissue
• increases in LPL activity provides clearance of TAG from both chylomicrons and VLDL

Question 18

how does a lack of insulin have an effect on protein synthesis?

Answer 18

loss of protein from the body due to “melting of flesh into urine”

Question 19

what effect does insulin have on protein synthesis?

Answer 19

• increases uptake of amino acids
• increases activity of protein synthesis enzymes
• reduces activity of protein catabolic enzymes

Question 20

what is insulin released stimulated by?

Answer 20

• increased blood glucose
• increases amino acids in plasma
• neural stimulation of pancreas
• gut hormones

Question 21

when is insulin release decreased by?

Answer 21

• reduction of blood glucose
• sympathetic neural stimulation

Question 22

what is the role of glucagon in regulation of metabolism during post-absorptive state?

Answer 22

• released by A cells of islets of langerhans
• increases glycogen breakdown in liver
• increases lipolysis
• increases gluconeogenesis in liver
• increases ketone body synthesis

Question 23

what can a severe negative energy balance lead to?

Answer 23

• a decline in metabolism
• decreases in bone mass
• reductions in thyroid hormones
• reductions in testosterone levels
• an inability to concentrate
• reduces physical performance

Question 24

what are the consequences of a positive energy balance?

Answer 24

• plaque can build up in arteries
• blood pressure increases
• total and LDL-cholestrol and TAG increases
• insulin’s resistance develops which leads to type 2 diabetes
• risk for cancer increases

Question 25

what happens to the control of nutrient metabolism during stress?

Answer 25

during stress the hypothalamus;amic-pituitary adrenal HPA axis is activated to regulate many body processes, including energy storage and expenditure

Question 26

what does cortisol do in control of nutrient metabolism during stress?

Answer 26

helps to regain glucose homeostasis:
- increases blood glucose through gluconeogenesis
- important role in glycogenolysis (breakdown of glycogen glucose) in liver and muscle tissue by facilitation of the activation of glycogen phosphorylase

Question 27

how does cortisol redistribute glucose in the control of nutrient metabolism during stress?

Answer 27

redistributes it to areas of the body that need it the most (heart brain) and away from digestive and reproductive organs

Question 28

what is the role of epinephrine and norepinephrine in control of nutrient metabolism during stress?

Answer 28

to provide increase in fatty acids required for energy ATP production by
- inhibiting insulin secretion by pancreas
- triggering glucagon secretion in the pancreas
- stimulating glycogenolysis in the liver and muscle
- stimulating glycolysis in muscle

Question 29

what is the role of growth hormone in the control of nutrient metabolism during stress?

Answer 29

• promotes lipolysis and fatty acid oxidation
• reduces liver uptake of glucose and helps to maintain plasma glucose concentration
• promotes gluconeogenesis in the liver

Question 30

what are hormonal responses to surgery?

Answer 30

• anterior pituitary ACTH increases
• growth hormone increases
• adrenal cortex cortisol increases
• aldosterone increases
• insulin often decreases
• glucagon usually small increases
• thyroid, thyroxine, tri-iodothyronine decrease

Question 31

what is the overall metabolic effect of the hormonal changes during surgery?

Answer 31

increases catabolism which mobilises substrates to provide energy sources and metabolism to retain salt and water and maintain fluid volume and cardiovascular homeostasis

Question 32

what do neuroendocrine, metabolic and inflammatory responses result in ?

Answer 32

substrate mobilisation
muscle protein loss
sodium and water retention
suppression of Anabolic hormone secretion

Question 33

does local anaesthesia or general anaesthesia associate with more patient stress?

Answer 33

general anaesthesia