week 1 teaching: homeostasis and diabetes Flashcards

1
Q

autoregulation

A

process that occurs when a cell, tissue, organ or organ system adjusts in response to some environmental change

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2
Q

extrinsic regualtion

A

process that results from the actitivites of the nervous system or endocrine system
these organ systems detect environmental change and send electrical signal (nervous system) or chemical messenger (endocrine system) to control/ adjust activites of other systems simultaneosuly

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3
Q

three parts a homeostatic regulatory mechanism consists of

A

receptor
control centre
effector

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4
Q

small change in the radius of a blood vessel

A

large effect on the flow of blood through capillaries and therefore large effect on blood pressure

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5
Q

if blood supply to tissue is inadequate

A

tissue becomes hypoxic- lack of oxygen

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6
Q

tissue becomes hypoxic,

A

Capillary Blood Flow: Local Autoregulation
potassium and acid e.g lactic leaks out of blood vessel
causes smooth muscle cells that surround the walls of arterioles to relax
increases the radius of arteriole
increasing blood flow to tissue
increasing O2 levels

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7
Q

positive feedback loop: blood clotting

A

damaged cells in blood vessel wall release chemicals that begin clotting process
chemicals start chain reactions in which cells, cell fragments and soluble proteins in the blood begin to form a clot
as clotting continues, each step releases chemicals that furhtur accelerates the process
formation of blood clot

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8
Q

dynamic equilibrium state

A

each physiological system functions to maintain a state of equilibrea, that keeps vital conditions within a normal range of values

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9
Q

metabolic rate

A

amount of energy used by a person per unit of time

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10
Q

basal metabolic rate

A

amount of energy per unit time that a person needs to keep a body functioning at rest

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11
Q

anabolism

A

set of metabolic pathways that construct molecules from smaller units

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12
Q

Catecholamines

A

any class of aromatic amines which include a number of neurotransmitters e.g adrenaline and dopamine

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13
Q

glycogenolysis

A

breakdown of glycogen

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14
Q

gluconeogenesis

A

generation of glucose from certain non-carbohydrate carbon substrates e.g glycerol and lactate

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15
Q

anabolic state

A

absorptive sate
energy stored in macromolecules

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16
Q

catabolic state

A

postabsorptive state
energy stores mobilised

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17
Q

metabolic reactions of anabolic state

A

insulin increases glycolysis and glycogenesis while inhibitng gluconeogenisis and gylcogenolysis
when blood glucose levels high, it is taken up by the liver and ised to provide acetyl co-A for fatty acid sysnthesis or stored as glycogen

18
Q

metabolic reactions of catabolic state

A

fasting state, dominated by secretion of glucagon, insulin release in minimal
metabolism focused on maintaining blood gluc conc by increased hepatic breakdown of glycogen and gluconeogenesis

19
Q

metabolic changes between anabolism and catobolism triggered by

A

endocrine signals involving pancreatic hormones insulin and glucagon
levels of insulin in blood trigger transition

20
Q

pancreas

A

mixed endocrine and exocrine glands located behind the stomach
innervated by the sympathetic and parasympathetic nervous system

21
Q

types of cells in the pancreas

A

acini
islets of langerhans

22
Q

acini

A

exocrine part which releases digestive juices

23
Q

lslets of langerhans

A

secrete 3 endocrine hormones
alpha cells: glucagon
beta cells: insulin
delta cells: somatostatin

24
Q

insulin

A

51 aa protein hormone
derived from precursor proinsulin
synthesised in RER
converted to insulin in GA, cleaved by proteolytic enzyme

25
insulin storage and secreted
insulin stored in beta cells until secreted into bloodstream by exocytosis
26
insulin circulating in blood is bound to
beta globulin (mostly)
27
half life of insulin in blood
5 mins
28
what allows the amount of plasma glucose circulating in blood to be regulated
levels of insulin in blood triggering transition between anabolic and catabolic states
29
what does insulin promote
synthesis of energy storage molecules and other processes of the anabolic state storage of FA and triglycerides in adipose tissue and liver glycogen synthesis in liver and muscle glucose uptake by the brain
30
main buffer system to regulate blood sugar levels
liver
31
what must be present in blood for growth hormone to have effect
insulin
32
what is glucagon where is it secreted
29 aa single chain polypeptide hormone synthesised in alpha cells of islets of Langerhans in pancreas released by exocytosis 6 min half life
33
what does glucagon promote
process of catabolism
34
what stimualtes glucagon secretion
hypoglycemia sympathetic nervous system and adrenaline
35
why does adrenaline stimualte glucagon secretion
maintain high circulating plasma glucose for fuel for cells 'fight or flight'
36
standard fasting blood glucose levels
70-110mg/dL
37
hyperglycemia blood glucose levels
>140mg/dL
38
hypoglycaemia blood glucose
<60mg/dL
39
adrenal corticosteriods
promotes glycogen production and maintains glycogen reserves
40
growth hormone
anti- insulin glucose-sparing agent important for bouts of starvation or fasting depresses glucose uptake making more glucose available for the brain
41
catecholamines
when glucose level fall below 4mmol l-1, mobilise glucose for use by the brain
42
thyroid hormones
enhance glucose metabolism ensuring glucose reserves are mobilised