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ISCM > NEURO PHYSIOLOGY > Flashcards

NEURO PHYSIOLOGY Flashcards

1
Q

what is the difference with paracrine and autocrine

A

paracrine is when the hormone affect local targets and autocrine is when they act on the producing cell itself

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2
Q

what are the three categories of hormones

A

peptides and proteins eg insulin
steroid hormones which are synthesised from cholesterol
amino acid derivatives eg adrenaline and thyroid hormones

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3
Q

which type of hormones need to be bound to carrier proteins and why

A

lipid soluble ones eg cortisol and T3,T4. the carrier proteins prevents it from degradation in the blood and it dissociates once at the receptor

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4
Q

how are peptide hormones produced

A

produced as prohormones which have reduced activity until they’re cleaved by endopeptidases.

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5
Q

where are hormones stored

A

in secretory granules that are released by exocytosis after the appropriate stimulus which is dependant on Ca 2+

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6
Q

how are steroid hormones produced

A

produced from cholesterol which is stored in lipid droplets within the cell until needed. hormone synthesis takes place in the mitochondria and SER. the hormone is made and released immediately upon stimulation

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7
Q

how are amino acid derivative hormones formed

A

the actecholines (adrenaline and noradrenaline) are synthesised from tyrosine residues and stored in secretory vesicles and rebased in response to an AP

T4 and T3 are formed by iodination of tyrosine resides and bind to intracellular receptor altering gene transcription. bind to thyroglobulin and slowly release hormones to target tissues

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8
Q

what is water soluble hormone signalling

A

hormone binds to the cell surface receptors to activate downstream signalling eg G proteins leading to camp as a second messenger. these pathways cause changes to specific cellular reaction resulting in the response hormone. causes an enzyme cascade which happens outside as it water soluble hormones can’t cross inside and so the cascade creates a final product which can cross and will create the effect the hormone needed to create

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9
Q

how does steroid hormone signalling work

A

the steroid hormone dissociates from carrier protein and can diffuse across the cell membrane to bind to an intracellular receptor. this complex acts as a factor which controls the expression of target genes. these pathways lead to changes in cellular reactions causing a response to the hormones

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10
Q

what is the target organ and the action of ACTH

A

adrenal cortex and its a stress response and sodium retention

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11
Q

what are the direct effects of GH

A
  • increased fatty acid use
  • decreased rate of glucose uptake and metabolism
  • glycogen breakdown
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12
Q

what are the indirect effects of GH

A

increased formation of collagen and deposition of bone matrix

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13
Q

disorders of growth hormone

A
  • hyper secretion in children results in gigantism and in adults acromegaly
  • hyposecretion results in pituitary dwarfism
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14
Q

what hormone does the pineal gland secrete

A

melatonin which induces sleep and resets the pacemaker of the circadian rhythm

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15
Q

how does the thyroid gland work

A

the stimulus causes the hypothalamus to release TRH and this causes the anterior pituitary to release TSH which causes the thyroid gland to release T3 and T4

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16
Q

how does the thyroid gland release T3 and T4

A
  • thyroglobulin molecules are packaged into vesicles and exocytosed into the lumen of the follicle.
  • the iodide ion enters through a sodium/iodide cotransporter and exits into the lumen through a chlorine/iodide antiport
  • iodide ions oxidized to iodine and added to the thyroglobulin
  • MIT, DIT, T3 and T4 mixture is formed
  • the mixture is endocytosed back into the follicle
  • the mixture undergoes proteolysis and the T3 and T4 is released
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17
Q

what is the function of T3

A
  • increases basal metabolic rate
  • maintain body temp
  • stimulate protein synthesis

it has a greater activity than T4

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18
Q

what is the function of the parathyroid hormone

A

involved in calcium homeostasis. Sustained levels of PTH acts to increase osteoclast activity and bone resorption, releasing calcium

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19
Q

what does PH do to kidney

A
  • increase reabsorption of calcium from urine
  • increases the expression of the enzyme which activates vitamin D
  • increases the excretion of phosphate
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20
Q

what is the function of vitamin D metabolite

A

increases the absorption of calcium and phosphate in the GI tract

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21
Q

what hormone does the zona glomerulosa produce

A

mineralcotricoid

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22
Q

what hormone does the zona fasiculata produce

A

glucocorticoids

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23
Q

what hormone does zona reticularis produce

A

adrenogens

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24
Q

what hormone does the medulla produce

A

catecholamine, noradrenaline and ardrenaline

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25
Q

what is the function of aldosterone

A

increases sodium and water reabsorption in the kidney

26
Q

what is the function of androgens

A

source of testosterone in women

27
Q

what is the function of cortisol

A

exerts anti-inflammatory effects and decreases immune response

28
Q

what are disorders of the adrenal gland

A

excessive cortisol leads to Cushing syndrome

29
Q

what is up regulation and down regulation

A

upregulation is when there is an increase in the number of receptors on the membrane and downregualtion is when there is a decrease in the number of receptors on the membrane

30
Q

what is hormone deficiency

A

often due to autoimmune destruction of the endocrine gland

31
Q

what is hormone resistance

A

mutation in hormone receptors which leads to downstream effects

32
Q

what is hormone excess

A

endocrine tumors antibody mediated trigger of hormone receptors

33
Q

what is the function of insulin

A

increase glucose absorption from the blood and stimulates glycogen formation

34
Q

what is the function of glucagon

A

stimulates glycogenolysis and inhibits insulin release

35
Q

which cells in the islets of langerhan produce insulin and which ones produce glucagon

A

insulin- beta cells

glucagon beta cells

36
Q

where are the alpha cells located compared to beta cells

A

alpha cells line the centre and beta cells surround it

37
Q

what is the normal blood glucose level

A

4-6mmol/L

38
Q

how does glucose enter the cell

A

needs a glucose transporter which is the GLUT-2 transporter in beta cells

39
Q

how is insulin released

A

glucose enters beta cell and is metabolized. this leads to an increase in ATP. The potassium channel gets inhibited and this leads to depolarization and so Ca2+ enters and this leads to insulin secretion

40
Q

what are incretins

A

peptide hormone released by the intestine that act on pancreatic cells to stimulate insulin release

41
Q

what is the effect of insulin on target cells

A

insulin receptor is tyrosine-kinase linked and when insulin binds it leads to vesicles containing GLUT-4 to move to the membrane which increases transcription of glucose metabolism enzymes. this surpasses gluconeogenesis and increases potassium uptake

42
Q

what is the HbA1c test

A

older Hb binds to glucose and becomes glycated. an increase in blood glucose means increase in HbA1c and is used to indicate levels over three months

43
Q

what are the general effects of high blood glucose

A

increased thirst

increased appetite frequent urination

44
Q

what are the acute complications of high blood glucose

A

diabetic ketoacidosis
blurred vision
low consciousness
coma/death

45
Q

what are the long-term complications of high blood glucose

A

nerve damage
sigh loss
CV disease

46
Q

what is type 1 diabetes

T1DM

A

autoimmune

pancreas doesn’t produce insulin

47
Q

which group is most likely at risk of T1DM and what is the genetic susceptibility

A

north europeans

30% more likely if parents have it

48
Q

what is type 2 diabetes T2DM

A

insulin resistance

49
Q

which group is most likely at risk of T2DM and what is the genetic susceptibility

A

black African and carribean and south asians

75% more likely if relative has it

50
Q

what factors cause T2DM

A

insulin resistance causes more glycogen to be broken down and increased blood glucose levels

insulin resistance also causes less glucose uptake from blood

51
Q

what are the treatments for diabetes

A

T1DM-diet and exercise and insulin

T2DM-diet and exercise and drugs e.g. metformin

52
Q

what is double diabetes and how is it caused

A

when someone has type 1 and they get onto insulin which causes weight gain this then can lead to insulin resistance which is type 2

53
Q

what is gestational diabetes

A

high blood glucose without type 1 or type 2 but is cause by insulin resistance

3-9% of preganancies

54
Q

what are the risks to a child when the mother has gestational diabetes

A 
oversize 
newborn low on sugar 
jaundice 
higher risk of obesity 
x6 of getting T2DM
55
Q

what is the link between Alzheimers and diabetes

A

an increased risk of AD with diabetes. insulin resistance lowers energy of metabolism and so increases stress on brain cells which can lead to AD

56
Q

what are some complications of diabetes

A

frequent urination due to increased osmotic pressure in blood

increase in thirst (polydipsia)

57
Q

what is diabetic neuropathy

A

-nerve damage due to damage to small blood vessels and toxins

58
Q

what is diabetic ketoacidosis

A

cells are unable to transport glucose and so consume fats for energy

fats breakdown to produce acidic ketones which leads to low pH

59
Q

what are symptoms of ketoacidosis

A 
muscle pain 
heart palpitations 
nausea vomiting 
coma 
death
60
Q

what is hypoglycaemia

A

low blood glucose which leads to inability to provide energy to neurons

61
Q

what are symptoms of hypoglycemia

A 
headache 
dizziness 
blurred vision 
hunger 
tachycarida 
shaking

ISCM (19 decks)

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