Week 2- hormonal responses to exercise Flashcards
How is plasma glucose levels maintained during exercise?
- mobilisation of glucose from liver glycogen stores
- mobilisation of FFA from adipose tissue, spares blood glucose
- Gluconeogenesis from amino acids, lactic acid and glycerol
- blocking entry of glucose into the cells
How do slow-acting hormones act?
in a permissive manner to allow other hormones to exert their full force
What is the role of the thyroid hormone?
Influence the number of receptors on the surface of the cell for other hormones to react with
What does Triiodothyronine enhance?
effect of epinephrine to mobilise free fatty acids from adipose tissue (T3)
What is the role of growth hormones?
-essential for growth of all tissues
-increases amino acid uptake and protein synthesis
-spares plasma glucose
-mobilises fatty acids from adipose tissue
What changes to plasma GH when exercise intensity increases?
Plasma growth hormone increases
What is cortisol?
Steroid hormone derived from cholesterol and secreted from the adrenal cortex
-contributes to the maintenance of plasma glucose
What is cortisol stimulated by?
-stress via adrenocorticotrophic hormone (ACTH)
-exercise
What is diurnal variation?
concentrations peak on the morning and drop throughout the day
What are the effects of cortisol mediated by?
DNA transcription and translocation to protein synthesis
Where are catecholamines secreted from?
adrenal medulla
What kind of hormone is epinephrine and norepinephrine?
Fast acting hormones part of the fight or flight response
What increases epinephrine and norepinephrine?
-exercise
-increased BP and HR during exercise
What causes a rapid decrease in catecholamines?
endurance training
What causes more rapid glycogen depletion?
high intensity exercise
What is the role of plasma epinephrine?
stimulate glycogenolysis via b1 receptor
Where does the pancreas secrete counter-regulatory hormones from?
islets of Langerhans
What is the role of insulin when released from b cells?
promote the storage of glucose and amino acids and fats
What is the role of glucagon when released from a cells?
promote the mobilisation of fatty acids and glucose, stimulates gluconeogenesis in the liver
How much does insulin concentration drop during moderate intensity exercise?
~50%, favouring the metabolism of glucose from the liver and FFA from adipose tissue
What is the primary stimulus for the secretion of insulin and glucagon?
Plasma glucose
What do hormones that are elevated during exercise favour?
Mobilisation of fat
Why does FFA oxidation decrease during heavy exercise?
- high levels of lactic acid
- increase hydrogen concentration inhibits HSL
3.inadequate blood flow to adipose tissue - insufficient albumin to transport FFA in plasma
