Hormones and behaviour

Question 1

What’s the difference between hormones and neurotransmitters?

Answer 1

Hormones transported in blood to target cell

Neurotransmitter from neuron to neuron via action potentials

Question 2

What are the 2 main mechanisms of hormone action on cell?

Answer 2

Rapid, non-genomic: Hormone enters cell through receptor (–> alter cell function)

Slow genomic: Hormone enters through cell wall and binds to steroid receptor inside the cell which can then enter nucleus (–> new protein production)

Question 3

What is the main purpose of the pituitary gland?

Answer 3

Links hypothalamus (and is responsible for blood flow)

Question 4

Which types of hormones does hypothalamus and the pituitary gland release?

Answer 4

Hypo: Releasing/Inhibiting hormones (eg Growth hormone inhibitory/releasing hormone)
Pituitary gland: stimulating hormones (eg growth hormone)

Question 5

What are the actions of adrenocorticoids?

Answer 5

• balance of tissue absorption and breakdown of amino acids (protein), carbohydrates and fat
• immune function balance
• electrolyte/mineral balance
• From adrenal glands (just above kidneys)

Question 6

How is cortisol related to chronic stress (and depression)?

Answer 6

Chronic stress/depression –> blunted cortisol response to stress

Question 7

What is the effect of stress on immune functions?

Answer 7

Acute stress –> improves immunity

Chronic stress –> suppresses immunity

Question 8

Which behaviours does hypothalamus control and how?

Answer 8

• Emotional: limbic system message –> hypo –> mediates autonomic emotional response (ie sweating)
• Ingestive (eating/drinking): Pheripheral signals from digestive system & body fat –> hypo
  Various peptide hormones (eg insulin) involved in feeling full/hungry

Question 9

What are neurohormones?

Answer 9

Substances released by NEURONES into bloodstreem (eg oxyticin / vasopressin)

Question 10

What are the 2 internal triggers for thirst?

Answer 10

1) Hypovolaemic: fluid contents of blood falls –> detected by baroreceptors in blood vessels –> renin from kidneys released –> angiotensin in blood –> detected by brain
2) Osmotic: Increased concentration of exracellular fluid detected by osmosensory neurons in brain

• -> Thirst!
• NB most drinking is habitual not thirst driven

Question 11

What is the roles of oxytocin?

Answer 11

• lactation and maternal behaviour
• ‘the empathy hormone’ (pair-bonding, facial emotional recognition, aggression, trust etc)
• vasopressin also plays a part

Question 12

Describe the chromosomal sex development

Answer 12

• SRY gene is contained on Y gene –> presence/absence determine development of testis or ovaries
• embryonic ovaries dormant, testes make androgens and peptide hormones –> sex organs (being male requires masculinisation or defeminisation)