7- Neurohormones

Question 1

What are endocrine hormones?

Answer 1

Hormones that are released directly into blood circulation

Question 2

What are the principal endocrine organs of the body and what do they release?

Answer 2

• testes: testosterone
• ovaries: oestrogen and progesterone
• pancreas: insulin, glucagon, somatostatin
• adrenal gland: cortex= aldosterone and cortisol medulla= epinephrine and norepinephrine
• parathyroid gland: parathyroid hormones
• thyroid gland: thyroxine, triiodothyronine and calcitonin
• pituitary
• hypothalamus

Question 3

What are the hormones of the hypothalamus?

Answer 3

TRH
GRH
CRH
Growth Hormone releasing hormone (GHRH)
prolactin inhibiting factor (dopamine)
somatostatin

Question 4

What are the hormones of the anterior pituitary gland?

Answer 4

thyroid stimulating hormone
LH
FSH
Growth hormone
prolactin
adrenocorticotropin

Question 5

What are the hormones of the posterior pituitary?

Answer 5

vasopressin and oxytocin

Question 6

What are the different types of neuron communications?

Answer 6

• point to point communication
  fast and restricted
• neurons of secretory hypothalamus (neurohormones)
  slow but widespread
• networks of interconnected neurons autonomic nervous system
  fast and widespread influence
• diffuse modulatory systems (monoamines)
  slower and widespread

Question 7

What are the 2 main control systems of the body?

Answer 7

• the endocrine system
• the nervous system

Question 8

Compare the endocrine and nervous systems

Answer 8

endocrine system:

• Mediators travel within blood vessels
• Utilises chemical mediators (hormones)
• Slow communication
• Effects can be long-lasting

nervous system:

• Signalling along nerve fibres
• Transmission of electrical impulses
• Fast communication
• Effects are generally short-acting

Question 9

What are neurohormones?

Answer 9

• Neurohormones are produced by specialised nerve cells called neurosecretory cells and released into the blood.
• Because they are defined as hormones, they are secreted into the blood and have their effect on cells some distance away,
• but the same compounds can also act as neurotransmitters or as autocrine (self) or paracrine (local) messengers.

Question 10

What are the different types of hormones?

Answer 10

Protein and peptide
Amino acid derivatives
Steroid hormones

Question 11

What are the properties of protein and peptide hormones?

Answer 11

• they vary in size
• can be synthesised as a large precursor and processed prior to secretion (e.g. GH, somatostatin, insulin)
• can be post translationally modified (in the golgi body)
• can have multiple subunits synthesised independently and assembled (e.g. FSH,LH,TSH)

Question 12

What are the properties of amino acid derivative hormones?

Answer 12

• they are mostly tyrosine derived
• neurotransmitter that can also act as a hormone
• eg. adrenaline. noradrenaline and dopamine

Question 13

What are the properties of steroid hormones?

Answer 13

• Steroid is a class of lipids derived from cholesterol
• eg. cortisol, aldosterone, testosterone, progesterone and oestradiol

Question 14

Describe the anatomy of the hypothalamus-hypophyseal system