week 1 teaching: homeostasis and diabetes

Question 1

autoregulation

Answer 1

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

Question 2

extrinsic regualtion

Answer 2

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

Question 3

three parts a homeostatic regulatory mechanism consists of

Answer 3

receptor
control centre
effector

Question 4

small change in the radius of a blood vessel

Answer 4

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

Question 5

if blood supply to tissue is inadequate

Answer 5

tissue becomes hypoxic- lack of oxygen

Question 6

tissue becomes hypoxic,

Answer 6

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

Question 7

positive feedback loop: blood clotting

Answer 7

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

Question 8

dynamic equilibrium state

Answer 8

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

Question 9

metabolic rate

Answer 9

amount of energy used by a person per unit of time

Question 10

basal metabolic rate

Answer 10

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

Question 11

anabolism

Answer 11

set of metabolic pathways that construct molecules from smaller units

Question 12

Catecholamines

Answer 12

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

Question 13

glycogenolysis

Answer 13

breakdown of glycogen

Question 14

gluconeogenesis

Answer 14

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

Question 15

anabolic state

Answer 15

absorptive sate
energy stored in macromolecules

Question 16

catabolic state

Answer 16

postabsorptive state
energy stores mobilised

Question 17

metabolic reactions of anabolic state

Answer 17

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

Question 18

metabolic reactions of catabolic state

Answer 18

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

Question 19

metabolic changes between anabolism and catobolism triggered by

Answer 19

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

Question 20

pancreas

Answer 20

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

Question 21

types of cells in the pancreas

Answer 21

acini
islets of langerhans

Question 22

acini

Answer 22

exocrine part which releases digestive juices

Question 23

lslets of langerhans

Answer 23

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

Question 24

insulin

Answer 24

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

Question 25

insulin storage and secreted

Answer 25

insulin stored in beta cells until secreted into bloodstream by exocytosis

Question 26

insulin circulating in blood is bound to

Answer 26

beta globulin (mostly)

Question 27

half life of insulin in blood

Answer 27

5 mins

Question 28

what allows the amount of plasma glucose circulating in blood to be regulated

Answer 28

levels of insulin in blood triggering transition between anabolic and catabolic states

Question 29

what does insulin promote

Answer 29

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

Question 30

main buffer system to regulate blood sugar levels

Answer 30

liver

Question 31

what must be present in blood for growth hormone to have effect

Answer 31

insulin

Question 32

what is glucagon where is it secreted

Answer 32

29 aa single chain polypeptide hormone
synthesised in alpha cells of islets of Langerhans in pancreas
released by exocytosis
6 min half life

Question 33

what does glucagon promote

Answer 33

process of catabolism

Question 34

what stimualtes glucagon secretion

Answer 34

hypoglycemia
sympathetic nervous system and adrenaline

Question 35

why does adrenaline stimualte glucagon secretion

Answer 35

maintain high circulating plasma glucose for fuel for cells ‘fight or flight’

Question 36

standard fasting blood glucose levels

Answer 36

70-110mg/dL

Question 37

hyperglycemia blood glucose levels

Answer 37

> 140mg/dL

Question 38

hypoglycaemia blood glucose

Answer 38

<60mg/dL

Question 39

adrenal corticosteriods

Answer 39

promotes glycogen production and maintains glycogen reserves

Question 40

growth hormone

Answer 40

anti- insulin glucose-sparing agent
important for bouts of starvation or fasting
depresses glucose uptake making more glucose available for the brain

Question 41

catecholamines

Answer 41

when glucose level fall below 4mmol l-1, mobilise glucose for use by the brain

Question 42

thyroid hormones

Answer 42

enhance glucose metabolism ensuring glucose reserves are mobilised