Hormones , Homeostasis, thermoregulation Flashcards
What is the function of insulin, Thyroxine, Glucagon, adrenaline and where are they produced
Insulin- Pancreas
Insulin- Lowers blood glucose
Thyroxine- Thyroid gland
Thyroxine- Controls the body’s metabolic reactions
Glucagon- Pancreas
Glucagon- Raises glucose
Adrenaline- Adrenal gland
Adrenaline- prepares body for physical activity
what are the effects of adrenaline
Increase heart rate
Increase breathing rate
- deeper breaths
- more frequent breaths
Decrease blood flow to inactive areas ( stomach)
Glycugon released to convert glycogen to glucose released into the blood
pupils dilate
-circular muscles relax
- Radical muscles contract
Skin hairs stand up
Brain - mental alternes increases
What is the effect of increased heart rate
Increase transport of oxygen
more glucose/oxygen to respiring cells in muscles
more aerobic respiration
more releasing of energy more muscles contraction so run faster
What is homeostasis
maintain a constant environment in the body
what happens to the body If you drink a litre of water
Increase water levels
Detected in osmoreceptors in hypothalamus
Picturality gland releases less ADH
No ADH in colleting duct
makes collecting duct less permeable
volume of h20 reabsorbed is less
urine is higher volume
lower concentration
what happens if you exercise
Loss of water
Detected by osmoreceptors in the hypothalamus
Picturality gland releases more ADH
More ADH in colleting duct more Water reabsorbed
Collecting duct is more permeable to water
Lower volume of urine
Higher concentration of urine
what is the effect of testosterone
Promotes male secondary sexual characteristics (facial hair)
What is the effect of eating a sugary meal
Blood glucose concentration increases
Change detected by cells in pancreas
Pancreas releases insulin
Liver cells store more glucose from the blood as glycogen
Decease in blood glucose
Blood concentration returns to set point
What is the effect of doing heavy exercise on glucouse levels
Decrease glucouse levels
Change detected by cells in pancreas
Pancreas releases Glucagon
Liver cells breaks down glycogen to release glucouse into the blood
increase in blood glucouse levels
returns back to set point
what is the effect of being in a hot environment
increased body temperature
Change detected in hypothalamus
alerts cooling mechanisms
Vasodilation- blood vessels dilate to increase heat loss via radiation
Sweet glands produce more sweat to increase heat loss by evaporation
hairs lie flat to prevent trapping of heat via insulation
no shivering occurs
Body decreases in temperature cooling mechanisms are switched off by thermostat in hypothalamus
return to normal body temp of 37
What is the effect of being in a cool environment
body temperature decreases
change detected in hypothalamus
heating mechanism turned on
sweat glands produce less sweat to prevent loss of heat via evaporation
Hairs stand up to create a layer of insulation and trap heat
vasoconstriction- blood vessels constrict to reduced heat loos via radiation
shivering- muscles contact rapidly to generate heat
exothermic process, more respiration, release atp
How do plants respond to stimuli
- grow towards the light for maximum light absorption for photosynthesis
respond to gravity, roots and shoots grow in the right direction
What is auxin
Auxin is plant growth hormones
where is auxin produced and it’s function
Auxin Is produced in the tips and diffuses backwards to stimulate the cell elongation process
what two process is auxin involved in
Plants growth towards the light (phototropism)
and plants growth towards gravity(geotropism)
How does positive phototropism work
Shoot grows toward the light
Auxin accumulates on the side in the shade
this makes the cells ellongate faster on the shaded side, so the shoot bends towards the light
grows towards light
How does negative geotropism work
when a shoot is growing sideways, gravity produces an unequal distribution of auxin in the tip,
with more auxin on the lower side
causes the lower side to grow faster bending the shoot upwards
grows away from gravity
What is positive geotropism
a sideways plant always has auxin on the lower side
The root has extra auxin which inhibits growth.
The cell on top elongate faster, and the root bends downwards
(grows towards garvity)
what is negative photoropism
Grows away from light
root exposed to light
more auxin accumulates on the more shaded side
auxin inhibits cell elongation on the shaded side
so the root bends downwards, back into the ground
roots that are underground are not exposed to light grow downwards sue to positive geotropism
