adrenal glands Flashcards
what is the adrenal gland ?
one pyramid-shaped adrenal glad
found on the top of each kidney
which two glands are the adrenal glands made up of ?
the inner medulla
outer cortex
what does the adrenal cortex do ?
secretes a group of steroid hormones
cortisone/ aldosterone + reproductive hormones
what does cortisone do ?
increases the bodies ability to resist stress of all kinds
anti-inflammatory + anti-allergic
what does aldosterone do ?
causes increased reabsorption of sodium ions from filtrate in kidney nephrons
+ simultaneous movement of potassium ions into filtrate
helps regulate the electrolyte levels of the body fluids
how is cortical activity controlled ?
low levels of aldosterone cause the hypothalamus to trigger a complex chain of reactions
(attempt to restore homeostasis)
> hypothalamus secretes releasing factors to stimulate anterior lobe of pituitary to release ACTH
> ACTH travels in the blood to adrenal cortex
adrenal cortex stimulated to release aldosterone + other hormones
how does ACTH control the levels of hormones in the blood ?
negative feedback
what does the adrenal medulla do ?
secretes adrenalin
what are the effects of adrenalin ?
the ‘fight or flight’ hormone is secretes in situations of sudden danger/ excitement
prepare body for action/ cope with emergency
same effects as sympathetic nervous system
list five affects of adrenalin ?
- blood pressure increased
- blood sugar levels are increased
- oxygen content of blood is raised
- skeletal muscle tone is increased
- heart rate is increased
what happens when blood pressure is increased ?
vasoconstriction (hollowing of blood vessels) takes place in skin + alimentary canal
enables more blood to go to the skeletal/ cardiac muscle where needed
what happens when blood sugar levels are increased ?
liver glycogen is converted to glucose
glucose is released in blood steam + provide fuel for energy release
what happens when oxygen content of blood is raised ?
breathing rate + depth of breathing is increased
extra oxygen is needed for increased respiration (more energy is released)
> rate - more impulses are sent to breathing muscles
depth - the brochial tubes dilate
what happens when skeletal muscle tone is increased ?
enables the muscles to respond more quickly
what happens when heart rate is increased ?
mood blood with higher levels of glucose/ oxygen going to muscles
cellular respiration increases in muscle cells
(more energy is made available for muscle activity)
