HOMEOSTASIS Flashcards
What is homeostasis
is the process by which your body maintains a constant internal environment
what internal conditions are controlled by homeostasis
blood glucose
body temperature
water
what does the nervous system consist of
the brain
the spinal cord
neurons
function of the cerebral cortex
responsible for consciousness, intelligence, memory and language
function of the medulla
responsible for unconscious activities such as breathing and controlling your heartbeat
function of cerebellum
responsible for muscle coordination
what happens when your short sighted (myopia)
cant see distant objects and the image focuses in front of the retina
What happens when your long sighted (hyperopia)
cant see close objects and the image focuses behind the retina
what happens to your body when you are cold
your hairs stand up to trap air
your blood vessels vasoconstrict- your blood vessels contract so that theyre further away from the skin, this makes less blood flow to the surface of the skin so less heat is lost
YOUR muscles and the exothermic reactions of respiration needed for muscle contraction raise the temperature
what happens to your body when you are too hot
hairs lie flat
sweating- water will evaporate, leading to heat and energy loss
vasodilation- blood vessels become wider allowing blood to flow closer to the surface of the skin so that heat can be lost
what does the endocrine system consist of (male and female)
pituitary gland secretes FSH
thyroid gland- produces thyroxin which regulates metabolism
adrenal glands- produces adrenaline, it is called fight or flight hormone as it is released when you are stressed or frightened
pancreas- produces insulin
ovaries- produce oestrogen (menstrual cycle)
testes- produce testosterone
how does your body regulate blood glucose (when its too high)
after eating blood glucose levels rise
the receptors in the pancreas recognises this and produces insulin
the insulin causes cells to remove glucose from the blood
liver and muscle cells convert glucose into glycogen and stores it
removing glucose from the blood causes blood glucose levels to fall
how does your body regulate blood glucose (when its too low)
when the blood glucose is too low this is picked up by the receptors in the pancreas
the pancreas starts to produce glucagon
the glucagon turns the glycogen that was stored in the liver and muscles into glucose
the glucose is released back into the blood
this causes the blood glucose levels to rise
type 1 diabetes
pancreas doesn’t work properly so doesn’t produce the right amount of insulin
how can you treat type 1 diabetes
insulin injections
symptoms of type 1 diabetes
loss of weight, increased need to urinate, thirstiness and hunger
type 2 diabetes
cells become insensitive to insulin
how can you treat type 2 diabetes
by controlling diet by eating less carbohydrates and exercise if that doesn’t work drugs can be prescribed- this helps the pancreas make more insulin
why is homeostasis important
it is important for maintaining optimal conditions for enzyme action and all cell functions
where are receptor cells found
in sense organs such as the eye,ear,nose,tongue and skin
the direction of electrical impulses in the nervous system
stimulus—receptor—-sensory neurone—-CNS—–motor neurone—– effector——response
sensory neurons carry……… from the………. to the…….
sensory neurons carry impulses from receptors to the CNS
Motor neurons carry……. from the …….. to the …….
motor neurons carry impulses from the CNS to the effectors
what are effectors and what do they do
effectors are muscles or glands and they respond to impulses, the muscles respond by contracting, the glands react by releasing chemicals
what are reflex actions
they are automatic and rapid reactions that do not involve the conscious parts of the brain
What happens in a reflex
a receptor detects a stimulus
a sensory neurone transmits the impulse to the CNS
a Relay neurone in the CNS passes the impulse on
a motor neurone is stimulated and passes the impulse to an effector
action is taken
what is a synapse
a gap between two neurons