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Biology > Module 5.4 > Flashcards

Module 5.4 Flashcards

Hormonal communication

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1
Q

what is the endocrine system

A

communication using hormones as signalling molecules

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2
Q

what does the endocrine system use to transport signals

A

the blood

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3
Q

what do endocrine glands do

A

manufacture and release hormones directly into the blood in capillaries running through the gland

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4
Q

how are hormones detected

A

target cells and target tissues
for peptide hormones the target cell must posses a specific receptor on their plasma membrane that is complimentary in shaped to that of the hormone

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5
Q

what are non-steroid hormones known as and why

A

first messengers
bind to cell surface membrane and initiate an effect inside the cell (usually cause the release of another signalling molecule (the second messenger))

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6
Q

how do peptide hormones work

A

G protein is activated when hormone binds to the receptor
G protein activates effector molecule (usually adenyl cyclase)
adenyl cyclase converts ATP to cAMP
cAMP is the second messenger which may initiate an enzyme cascade or act directly on a protein to alter the activity of the cell

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7
Q

what are the two parts of the adrenal glands

A

adrenal medulla (inner)
adrenal cortex (outer)

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8
Q

what are the three layers of the adrenal cortex

A

zona glomerulosa (outer)
zona fasciculata (middle)
zona reticularis (inner)

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9
Q

what hormones does the adrenal cortex produce

A

steroid hormones
cortisol
aldosterone
precursor androgens

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10
Q

what hormones does the adrenal medulla produce

A

adrenaline
noradrenaline

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11
Q

action of steroid hormones

A

passes through plasma membrane of target cell
binds with specific receptor in cytoplasm
receptor-steroid complex enters the nucleus and binds to specific receptor on chromosomal material
binding stimulates production of mRNA which code for the production of proteins

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12
Q

what does aldosterone do

A

help control concentrations of sodium and potassium in the blood
as a result they contribute to maintaining blood pressure

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13
Q

what does cortisol do

A

helps to control the metabolism of carbohydrates, fats and proteins in the liver

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14
Q

what do precursor androgens do

A

taken up by the ovaries or tests and converted to sex hormones

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15
Q

role of adrenaline

A

prepare the body for activity
relax smooth muscles in bronchioles
increase HR and stroke volume
vasoconstriction to raise bp
conversion of glycogen to glucose
inhibits the gut
dilates pupils

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16
Q

what are the two functions of the pancreas

A

exocrine - secretion of pancreatic juices containing enzymes into the gut
endocrine - islets of Langerhans secrete hormones into the blood

17
Q

where are the endocrine cells in the pancreas

A

islets of Langerhans

18
Q

what do islets of Langerhans contain

A

alpha cells
beta cells

19
Q

what do alpha cells secrete

A

glucagon

20
Q

what do beta cells secrete

A

insulin

21
Q

what channels do beta cells have and which are normally open

A

potassium and calcium ion channels
potassium is normally open
calcium is normally closed

22
Q

why are potassium ion channels normally open

A

potassium ions diffuse out of the cell to make the inside of the cell more negative

23
Q

what happens to beta cells when glucose concentrations outside the cell are too high

A

glucose molecules move into the cell
glucose is used to produce atp

24
Q

what happens when there is extra atp in beta cells

A

potassium channels close

25
Q

what happens when potassium channels close

A

potassium can no longer diffuse out of the cell making the cell less negative inside
change in potential difference opens calcium ion channels

26
Q

what happens when calcium ion channels are open

A

calcium ions enter the cell and cause insulin secretion by making vesicles containing insulin move to the cell surface membrane and fuse with it to release insulin by exocytosis

27
Q

what happens when blood glucose is too high

A

high blood glucose concentration detected by beta cells
insulin is secreted
target cells are liver cells, muscle cells and other body cells e.g. in the brain
target cells have membrane bound receptors
binding of insulin to receptors activates enzyme cascade

28
Q

what does insulin do

A

more transporter proteins specific to glucose are placed into the cell surface membrane
more glucose enters the cell
glucose is converted to glycogen for storage
more glucose is converted to fats
more glucose is used in respiration

29
Q

what is the conversion of glucose to glycogen called

A

glycogenesis

30
Q

what happens when blood glucose drops too low

A

detected by alpha cells
glucagon is secreted into the blood
targets hepatocytes in the liver
glucagon bind to membrane bound receptor
activates G protein
ATP to cAMP
enzyme cascade

31
Q

what does glucagon do

A

glycogen is converted to glucose
more fatty acids are used in respiration
amino acids and fats are converted unto additional glucose

32
Q

what is the conversion of glycogen to glucose called

A

glycogenolysis

33
Q

what is the conversion of amino acids and fats to glucose called

A

gluconeogenesis

33
Q

what is diabetes mellitus

A

when the body is no longer able to produce insulin

34
Q

type 1 diabetes

A

usually starts in childhood
autoimmune response where the immune system attacks the beta cells
insulin dependent

35
Q

type 2 diabetes

A

non-insulin dependent
produce insulin but not enough
cells are less responsive to insulin
can be brought on by obesity, high sugar diet, lack of exercise, ethnicity

36
Q

treatment for type 1 diabetes

A

insulin injections
islet cell transplant
pancreas transplant
stem cell treatment

37
Q

type 2 diabetes treatments

A

change in lifestyle
loose weight
exercise
diet monitoring
medication

38
Q

source of insulin for treating diabetes

A

genetically modified bacteria

Biology (18 decks)

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