Session 11- Metabolic and endocrine control during special circumstances Flashcards Preview

Metabolism, Endocrinology and Haematology > Session 11- Metabolic and endocrine control during special circumstances > Flashcards

Flashcards in Session 11- Metabolic and endocrine control during special circumstances Deck (19)
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1
Q

What fuels are normally available in blood

A

Glucose and fatty acids

2
Q

What fuels are available under special conditions

A

Amino acids

Ketone bodies

Lactate

3
Q

Acute effects of hypoglycaemia

A
Trembling 
Weakness
Tiredness
Headache 
Sweating 
Sickness
Tingling around the lips 
Palpitations 
Changes in mood 
Slurred speech 
Staggering walk
4
Q

Actions of insulin

A

Increases glucose uptake and utilisation by muscle and adipose tissue

Promotes storage of glucose as glycogen in liver and muscle

Promotes amino acid uptake and protein synthesis in liver and muscle

Promotes lipogenesis and storage of fatty acids as triacylglycerols in adipose tissue

5
Q

Effects of fasting

A

• Glycogenolysis in the liver to maintain blood glucose for the brain
and other glucose dependent tissues.
• Lipolysis in adipose tissue to provide fatty acids for use by tissues.
• Gluconeogenesis to maintain supplies of glucose for the brain.

6
Q

How is insulin involved in maternal metabolism

A

Increases as pregnancy proceeds ad it acts to promote the uptake and storage of nutrients largely as fat in maternal adipose tissue

7
Q

What is the role of the foetal-placental hormones

A

Oppose the actions of insulin

- impaired glucose uptake in maternal adipose and muscle

8
Q

What are the anti- insulin hormones of placental origin

A

Human placental lactogen

Progesterone

Corticotropin releasing hormones

9
Q

Metabolic changes during the first half of pregnancy

A

Related to a prep increase in maternal nutrient stores ready fo the more rapid growth of the foetus, birth and subsequent lactation

Increasing levels of insulin promote an anabolic state in the mother that results in increased nutrient storage

10
Q

How are the demands of the foetal-placental unit for nutrients met during the second half of pregnancy

A

Reducing the maternal utilisation of glucose by switching tissues to the use of fatty acids

Delaying the disposal of maternal nutrients after meals

Releasing fatty acids from the stores built up during the first half of pregnancy

11
Q

What is gestational diabetes

A

In some women the endocrine pancreas is unable to respond to the metabolic demands of pregnancy and the pancreas fails to release the increased amounts of insulin required. As a consequence there is a loss of control of metabolism, blood glucose increases and diabetes results (Gestational Diabetes).

After birth, when the increased
metabolic demands of pregnancy are removed and hormone levels change, the endocrine pancreas can respond adequately and the
diabetes disappears.

12
Q

Metabolic response to exercise

A

• The increased energy demands of skeletal and cardiac muscle
are met by mobilisation of fuel molecules from energy stores.
• There are minimal disturbances to homeostasis by keeping the
rate of mobilisation equal to the rate of utilisation.
• The glucose supply to the brain is maintained (prevent
hypoglycaemia).

13
Q

Advantages of using muscle glycogen over circulating glucose

A

Availability not affected by blood supply

No need for membrane transport into muscle cells

Produces G-6-P without using ATP

Mobilisation can be very rapid.

14
Q

Metabolic response to short-duration high intensity exercise

A
  • muscle ATP and C~P are used initially
  • muscle glycogen is rapidly mobilised to provide glucose 6-P
  • Glucose 6- is metabolised via glycolysis to provide ATP from ADP by substrate level phosphorylation
  • build up of H+ causes fatigue
  • dramatic increase in anaerobic resp
15
Q

Effect of H+ on anaerobic metabolism

A

Build up of lactate and H+ which exceeds the buffering capacity of the muscle cells and impairs their function producing fatigue

16
Q

Metabolic response to medium duration medium exercise

A

•The initial sprint which uses muscle ATP, C~P and anaerobic glycogen metabolism
• A long middle phase in which ATP is produced aerobically from
glycogen in muscle. This relies on an adequate supply of O2 to
muscles.
• A final finishing burst which relies on the anaerobic metabolism
of glycogen and produces lactate

17
Q

Metabolic responses during a marathon

A

Progressive fall in the insulin/anti-insulin ratio

  • increased glycogenolysis in liver
  • increases lipolysis in adipose tissue
  • no effect on ketogenesis in liver
18
Q

What is fatigue

A

The inability to maintain a given power output affecting the intensity and/or duration of exercise

19
Q

Causes o fatigue

A

Depletion of muscle glycogen

Accumulation of H+ in muscle

Dehydration