Endocrine System

Question 1

Functions of endocrine system

Answer 1

• Regulate metabolism
• Regulates balance of ions, water and nutrients in bloodstream
• Controls response to stress
• Regulates growth, development and reproduction
• Produces hormones

Question 2

Inputs that control hormone secretion

Answer 2

• Humoural stimulation - ions/nutrients
• Neural stimulation - neurotransmitters
• Tropic hormones - usually induce growth and development of target gland

Question 3

• Derived from tyrosine
• Includes
  * Thyroid hormones
  * Epinephrine
  * Norepinephrine
  * Dopamine

Answer 3

Amine hormones

Question 4

Types of hormone action

Answer 4

• Intracrine
• Autocrine
• Paracrine
• Endocrine
• Neuroendocrine

Question 5

• Majority of proteins
• Includes - insulin, glucagon, GH, leptin
• Usually synthesized as protein prohormones by ribosomes in endocrine cells
• Packaged into secretory vesicles
• Stored inside cells
• Released into bloodstream when cells stimulated

Answer 5

Peptide & Protein hormones

Question 6

• Derived from cholesterol
• Hydrophobic
• Primarily produced in adrenal cortex

Answer 6

Steroid hormones

Question 7

Mechanisms of hormone action depends on…

Answer 7

Location of receptor proteins, which depends on water solubility of the hormone

Question 8

Hormone-Receptor Interaction

Answer 8

• Number of receptors is limited, hormone action will reach saturation point
• Number of receptors could be regulated by availability of hormone in blood plasma
• Some hormones regulate the receptors for other hormones

Question 9

Endocrine Control of Growth

Answer 9

• Growth hormone and IGF
• Thyroid hormones
• Insulin
• Sex hormones
• Cortisol

Question 10

• Major stimulus of postnatal growth
• Stimulates liver to secrete IGF-1
• Stimulates protein synthesis
• Affects muscle, bone, adipose and liver growth
• GH released is stimulated during exercise and this stimulates growth via release of IGF-1

Answer 10

Growth hormone and IGF

Question 11

• Permits action of epinephrine and norepinephrine on muscles and blood vessels
• Promotes glucose synthesis in the liver during long term fasting and exercise
• Increases lipolysis in adipose tissue
• Maintains cellular concentrations of metabolic enzymes required to produce glucose and fatty acids between meals
• Decreases events associated with inflammatory response
• Elevated in the morning

Answer 11

Cortisol response to chronic stress

Question 12

• Increased availability of energy in the blood
• Increased HR, breathing rate and cell metabolism
• Dilation of major blood vessels and constriction of peripheral capillary.

Answer 12

Fight or flight response to stress or stimulin mediated by epinephrine and norepinephrine

Question 13

• Increases glucose uptake and storage in adipose and muscle tissues
• Increases glucose uptake and storage in the liver
• Decreases hepatic glucose production
• Increases amino acid uptake and protein synthesis
• Decreases triglyceride breakdown

Answer 13

Function of insulin

Question 14

• Strongly opposes action of insulin
• Acts mainly on liver
• Promotes glycogenolysis
• Stimulates gluconeogenesis

Answer 14

Function of glucagon

Question 15

Regulation of glucose metabolism during exercise

Answer 15

• Glucagon secretion
• Epinephrine and norepinephrine increases glycogenolysis
• Cortisol to promote protein catabolism
• GH to increase fatty acid oxidation, lipolysis and gluconeogenesis