hormones

Question 1

define: hormone

Answer 1

: chemical messenger required in small quantities that is secreted by specialised endocrine cells in one part of the body, and travels via the bloodstreams to a target organ/cell where it effects a response.

Question 2

where are hormones produced?

Answer 2

endocrines or other glands/tissues

Question 3

types of hormones?

Answer 3

aminio acid derivatives (hydrophilic, ine), lipid derivatives (hydrohobic, ol/one like testosterone/cortisol), peptide and protein hormones

Question 4

how are hydrophilic hormones transported?

Answer 4

in solution in blood from site of production to targets

Question 5

how are hydrophobic hormones transported

Answer 5

in solution in blood from site of production to targets AND attached to protein carriers

Question 6

stimulus response model for hypothermia/hyperthermia?

Answer 6

Stimulus: drop/raise in cbt
Receptors: thermoreceptors in hypothalamus
Modulator:
• Hypothalamus detects fall in body temp and produces more thyrotropin-releasing hormone (TRH)
• TRH stimulates pituitary gland to release more thyroid stimulating hormone (TSH)
• TSH stimulates thyroid gland to release more thyroxine, which increases metabolic rate

Effectors: all body cells
Response: increase/decrease in metabolic rate and hence heat production
Feedback: negative – reverses stimulus to increase body temp.

Question 7

stimulus response model for dehydration/overhydration?

Answer 7

opposite for overhydration
• • Stimulus: decreased water levels, increase solute concentration
• Receptor: osmoreceptors in the hypothalamus
• Modulator: hypothalamus sends to pituitary gland to release antidiuretic hormone
• Effector: kidney tubules, which become more permeable to water
• Response: increased water reabsorption and decreased urine volume

Question 8

stimulus response model for hyperglycaemia?

Answer 8

• Stimulus: increased BGC
• Receptor: chemoreceptor cells in pancreas
• Modulator: beta cells of Islets of Langerhans of pancreas, which secrete more insulin
• Effector: glucose is stored as glycogen in liver and muscle cells
• Response: decrease in BGC
Note: glucagon and insulin are termed antagonistic hormones: they oppose each other’s actions.

Question 9

stimulus resopnse model for hypoglycaemia

Answer 9

• Stimulus: decreased BGC
• Receptor: chemoreceptor cells in pancreas
• Modulator: alpha cells of Islets of Langerhans of pancreas, which secrete more glucagon
• Effector: stored glycogen in liver and muscle cells is broken down into glucose, which is released into bloodstream
• Response: increase in BGC