hormones

Question 1

hormonesd def

Answer 1

Def: a chemical subs produced in minute quantities by an endocrine gland. It is transported in the bloodstream to target organs where it exerts its effects. After hormones have performed its function, they are eventually destroyed in the liver.

Question 2

what is an Endocrine gland + e.gs

Answer 2

Ductless glands that secrete hormones directly into the bloodstream
Has an extensive network of blood vessels to transport hormones to organs
E.g. pituitary gland, adrenal gland,
Pancreas is both an endocrine gland an exocrine gland

Question 3

islets pf langerhans of pancreas (endocrine gland)

Answer 3

When BGC increases below norm, islets of langerhans are stimulated to secrete insulin into bloostream
the liver cells are stimulated to convert excess glucose into glycogen
Increases permeability of cell membrane of liver and muscle cells to glucose molecules. More glucose molecules diffuse into the liver and muscle cells
Increases oxidation of glucose by cells during respiration
decrease conversion of fatty acids and aacids into glucose in liver

When BGC decreases above norm, xxx glucagon
Converts glycogen back into glucose
Converts fats and amino acids into glucose
Converts lactic acid into glucose

Question 4

effects of lack of insulin

Answer 4

Abnormally high BGC
Tissue cells cannot utilise or store glucose
Diabetes mellitus

Question 5

signs of diabetes mellitus

Answer 5

Persistently high BGC
Presenc eof glucose in urine after a meal
Healing of wounds is slow and difficult

Question 6

adrenaline desc

Answer 6

Short lived effects
Nerve impulse pathway:
- Anxiety stimulates hypothalamus
-Nerve impulse is generated and transmitted to spinal cord via sensory neurone
-Adrenal gland is stimulated to produce and secrete adrenaline
-Adrenaline is transported to target organs
-Targetorgans respond to the short term effect of adrenaline
(this involved hormonal and nervous system!)

Question 7

effectsof adrenaline

Answer 7

Increases rate of heartbeat and blood pressure
Increases rate of ventilation
Causes pupils to dilate
Increases rate of blood clotting
Constricts artioles in skin
Constricts arterioles to gut
Contracts hair muscles
increases BGC
Increases metabolic rate

Question 8

similarities btwn endocrine control and nervous control

Answer 8

both transmits messages in body
both trigger responses
Serves as a means of coordination in the body

Question 9

differences between nervous control and endorine control

Answer 9

Nervous control VS Endocrine control
Involves neurons VS Involves hormones

Chemical and electrical transmission VS Chemical transmission

Nerve impulses transmitted by neurons VS Hormones transported by blood

Rapid transmission and response VS Slower transmission and relatively slow acting

Short term effects VS Can be short term or long term effects

Voluntary or involuntary VS Always involuntary

Localised effects VS Widespread effects