Exercise Phys 4: Endocrine response Flashcards

1
Q

Characteristics of steroid hormones and their receptors

examples?

A

Structurally related to cholesterol -> lipid soluble
- receptors usually intracellular -> effect protein synthesis/expression

e.g. cortisol, aldosterone (adrenal cortex)
testosterone, oestrogen

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2
Q

Characteristics of non-steroidal hormones and their receptors - 2 types

examples?

A

Large, not lipid soluble -> receptors usually on surface
- transduce extracellular to intracellular response

Peptide or protein hormones e.g. insulin + glucagon

AA derived e.g. Thyroxine, (nor)adrenaline

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3
Q

Characteristics of prostaglandins and receptors

example?

A

(pseudo)hormones -> derived from arachidonic acid

act as local hormones -> inflammatory response, swelling, vasodilation etc

e.g. thromboxane from platelets -> vasoconstriction

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4
Q

Processes and hormones which increase blood glucose during exercise?

A

Glycogenolysis -> (glycogen -> glucose)
Gluconeogenesis -> (FFAs, protein -> glucose)

Hormones 
Glucagon
Adrenaline
Noradrenaline
Cortisol
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5
Q

How does insulin affect glucose mobilisation by cells during exercise?

A

Insulin enables glucose uptake in muscle BUT

  • during exercise, insulin conc. decreases
  • cell sensitivity for insulin increases
  • > results in increased glucose uptake using less insulin
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6
Q

Describe pancreatic Beta cell release of insulin

A

Responds to changes (increase) in blood glucose
-> increases ATP synthesis in the cell

ATP blocks Katp (ATP sensitive potassium) ion channels

Depolarisation

  • > activates Ca2+ channels
  • > insulin release
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7
Q

Insulin promotes what on the cell surface?

A

Expression of GLUT4 transporters

-> increases glucose influx into cell

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8
Q

Describe glucagon release from pancreatic alpha cells

A

Responds to low blood glucose

  • fire action potentials
  • > provides steady release of glucagon
  • Ca2+ and Na2+ channels contribute to depolarisation
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9
Q

How does high glucose in the blood inhibit glucagon release?

A

Pancreatic alpha cells detect high glucose
- Katp blocked by increased ATP

Depolarisation
- > Na channels CANNOT RECOVER from inactivation

  • reduces Ca2+ entry
  • > reduced glucagon release
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10
Q

What pathway stimulates glycogenolysis?

A

Glucagon stimulates glycogenolysis via Gs/cAMP/PKA mediated pathway

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11
Q

How does adrenaline cause vasoconstriction in some areas but vasodilation in others?

A

binding to alpha-adrenoceptors in mesentery couples to Gq proteins
-> calcium channel activation + release and contraction -> vasoconstriction

binding to beta-adrenoceptors in skeletal muscle vessels coupled to Gs

  • > K channel activation, Ca2+ channel inactivation
  • > muscle relaxes, vasodilation
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