Neuroendocrine Flashcards

1
Q

What are hormones?

A

They are chemical messenger produced in one location and transported to a second location

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2
Q

What does the endocrine system do?

A
  • maintain homeostasis
  • regulate growth and development
  • control energy storage and use
  • mediate the body’s response to environmental cues
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3
Q

What is neurocrine communication?

A

When a hormone is a neurotransmitter

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4
Q

What is paracrine communication?

A

When a hormone acts on neighbouring cells

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5
Q

What is autocrine communication?

A

When a hormone hits back on its origin cell

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6
Q

What is the synergistic effect?

A

The effect of two hormones together is greater than the addition of the two effects

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7
Q

What is melatonin?

A

It is a product of tyrosine and it produced by the pineal gland. it is produced when it is dark, in order to adjust the circadian rhythm

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8
Q

What is the GHRH axis stimulated by?

A

exercise, stress, fasting, low glucose and sleep

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9
Q

What is the result of excess growth hormone production?

A

Giganticism (can be caused by a pituitary gland tumor, usually benign)

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10
Q

How do the hypothalamus and posterior pituitary communicate?

A

Hypothalamus neurons have their axon terminal projecting to the posterior pituitary

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11
Q

What hormones does the posterior pituitary produce?

A

oxytocin and vasopressin

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12
Q

What is vasopressin?

A

also called anti-diuretic hormone. VP is secreted in response to increased plasma osmotic pressure or increased blood volume. inhibits urine production and causes blood vessel contraction

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13
Q

what does oxytocin to?

A
  • it acts upon the kidney to promote sudium excretion,
  • increases release of atrial natriuretic factor from the heart,
  • contracts mammary ducts for milk let-down
  • causes uterine contraction during delivery
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14
Q

What 2 structures make up the matrix of the adrenal gland?

A
  1. cortex - capsulated the medulla, it on the outside

2. medulla - on the inside

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15
Q

Where are androgens secreted in the adrenal gland?

A

The reticularis zone

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16
Q

What does the adrenal medulla secrete?

A

E and NE

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17
Q

What is the steroid precursor?

A

cholesterol

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18
Q

What are the cardiovascular effects of adrenaline?

A
  • increase cardiac contractility
  • increase heart rate
  • dilate smooth muscle around arterioles
  • constrict other arterioles
  • shunt blood to exercising muscles and the brain
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19
Q

What hormone has similar metabolic effects to adrenaline?

A

cortisol

20
Q

What are the effects of chronic stress?

A

increased cortisol secretion, which leads to:

  • decreased immune function
  • increased risk of infection and cancer
  • worse diabetes due to anti-insulin effects
  • decreases bone density
  • induces infertility
21
Q

What is the kJ/g for carbohydrates, fat and protein?

A
carbohydrates = 17 kJ/g
protein = 17 kJ/g
fat = 37kJ/g
22
Q

How much kJ/g is there is one Cal?

A

Cal = 4.14kJ/g

23
Q

What is hypoglycaemia?

A

decreased CNS function, come and death due to decreased blood sugar levels

24
Q

What is hyperglycaemia?

A

too high blood glucose levels which can lead to osmotic duress, dehydration, vascular collapse or even death

25
Q

What makes glucose the main energy source?

A

it produces the most ATP

26
Q

What do pancreatic islet delta cells secrete?

A

somatostatin

27
Q

How many pancreatic islet of Langerhans are there?

A

1-3 million

28
Q

What is the structure of insulin receptor?

A

two extracellular alpha chains and two membrane spinning beta chains

29
Q

What is the incretin effect?

A

orally injected insulin leads to a large effect of insulin secretion, while when glucose is injected intravenously, insulin secretion is reduced. this is used as a marker for diabetes diagnosis.

30
Q

What is type I diabetes?

A

loss of beta cells in the pancreas leading to a deficiency in insulin. it is an autoimmune disease

31
Q

What is type II diabetes?

A

insulin resistance or reduce insulin sensitivity

32
Q

What organ controls the production of glucose in the liver?

A

the brain. we have an insulin receptor in the hypothalamus

33
Q

What is the accuracy of the difference between consumed and spent energy?

A

99.8%

34
Q

do humans have a hormone that can digest fructose?

A

no

35
Q

What do mutations in leptin receptors lead to?

A

they can lead to truncate of the intercellular domain, so when leptin binds so no signal is produced

36
Q

What happens when we get obese (in response to leptin)?

A

When we get obese, we absorb more fat and build more adipose tissues. this results in increased leptin secretion. however, leptin secretion is increased to the point where the leptin receptor in the hypothalamus becomes desensitised to leptin. now the brain is leptin resistant.

37
Q

What is gametogenesis?

A

sperm production in the testes and ova development in the ovary

38
Q

What are the units which produce sperm?

A

seminiferous tubules

39
Q

Where does storage of the sperm occur?

A

in the epididymis

40
Q

How many ovulation dominant follicles do we have?

A

~450

41
Q

What is the corpus luteum?

A

It is the remnants of the dominant follicle but without the ovum. it is made of enlarger granulosa cells

42
Q

What does the corpus lute secrete?

A

estrogen, progesterone and inhibin

43
Q

What is the folliclular phase?

A

it is follicular development, prior to ovulation

44
Q

What is the luteral phase?

A

when the corpus luteum is active, after ovulation

45
Q

How do the contraceptive pills prevent ovulation?

A

by maintaining negative feedback, so the LH surge doesn’t occur and neither does ovulation

46
Q

What is the LH surge?

A

After the estradiol levels reach a certain threshold for a minimum of 2 days—and perhaps because of the accelerated rate of estradiol secretion—the hypothalamic-pituitary axis reverses its sensitivity to estrogen. That is, estradiol now exerts positive feedback on the axis. The LH surge is an abrupt and dramatic rise in the LH level that occurs around the 13th to 14th day of the follicular phase in the average woman. The LH surge peaks ~12 hours after its initiation and lasts for ~48 hours. The LH surge causes the dominant follicle to rupture and releases its oocyte—ovulation.