B1 Homeostasis Flashcards
<p>what are hormones, where are they produced and how do they differ from nerves</p>
<p>Hormone - chemical messenger
Produced in the endocrine glands
hormonal effects are slower, longer lasting and more general in effects - Nervous control is quicker, shorter and more specified to one area</p>
<p>Definition of homeostasis</p>
<p>The maintenance of a constant internal environment </p>
<p>what internal conditions are controlled through homeoastasis</p>
<p>Temperature - (thermoregulation) to maintain the temperature at which enzymes work best
Blood sugar levels - to provide cells with a constant supply of energy
Water Content - (osmoregulation) water leaves the body when we breath out and when we sweat; excess water is lost in urine
Ion content - Ions are lost in our sweat and urine.</p>
<p>explain what happens when temperature increases</p>
<p>vasodilation - blood vessels widen allowing more blood to flow closer to the surface
heat radiates from the skin and is lost
sweat glands secrete sweat, which evaporates from the skin and takes away heat energy
hair erector muscles relax, so hairs lie flat allowing heat to escape</p>
what happens when its cold
vasoconstriction
very little heat lost by radiation
muscles contract quickly (shivering) which produces extra heat
sweat glands stop producing sweat
erector muscles contract so hairs stand up trapping a layer of hair
increased respiration helps generate heat, as does exercise
consequences of extreme high / low temperature
high - heat stroke, dehydration, death
low - hypothermia, death
Water is controlled how?
Osmoregulation:
The release of ADH (antidiuretic hormone) from the pituitary gland (ADH is made in the hypothalamus but stored in the pituitary gland) into the blood when there is not enough water in the body
or the suppression of ADH when there is too much water in the body.
the kidneys react to the presence of ADH
Homeostasis is an example of what feedback
Negative feedback - receptors detect change - these changes are processed - effectors bring about a response that reverses the change so that the normal level is restored.
why blood sugar controlled
too low then cells will not have enough to use for respiration, too high then it might start to pass out of the body in urine
which hormone controls glucose levels
Insulin
where is Insulin produced
pancreas
when is insulin produced
when glucose levels are high insulin is made in the pancreas and released into the blood. the insulin acts on the liver causing it to convert excess glucose in to glycogen for storage.
GLYCOGEN is
the liver converts excess glucose into glycogen to store it in the liver
(GLYCOGEN
GLYCOGON
glycogon is a hormone released by the pancreas when blood sugar levels are low, it causes the liver to convert glycogen back to glucose
(GLYCOGON FOR WHEN ITS GONE)
What is diabetes
a condition whereby a person cannot control their blood sugar levels
