Homeostasis And Response Flashcards
(31 cards)
Explain the stages in the reflex arc
1) stimulus detected by receptor 2)impulse sent almond sensory neurone to CNS 3)synapse at CNS - chemical diffuses across gap to trigger another impulse at the other receptor 4)impulse travels across relay neurone to another synapse in the CNS 5) motor neurone impulse from CNS to effector for a reflex action to happen
What 2 things can an effector be
A gland or a muscle
Name the three neurones in the reflex arc
Sensory, relay, motor
What does a receptor do
Converts change detected by stimulus to an electrical impulse to be sent along the sensory neurone
What is the CNS made up of
The brain and the spinal chord
What does the cerebral cortex control?
Language memory and consciousness
What does the medulla control?
Heart rate and breathing rate
What does the cerebellum control
Muscle movements and balence
Name the three ways to study the brain
1)brain damage patients 2) MRI scans 3) CAT scans
What does the retina do?
Contains sensory receptors that detect light intensity and colour and sends an impulse down he optic nerve to the brain
What happens to the iris in dark and bright light
In dark: pupil dilates
In bright: pupil retracts
What do the ciliary muscles and suspenders ligaments do?
Control the lens shape for seeing near and far objects
How does the ciliary muscles, suspenders ligaments and lens change when looking at a near object
CM: contract
SL: loosen
Lens: thicker refracts strongly
How does the ciliary muscles, suspenders ligaments and lens change when looking at a far object
CM: relax
SL: pulled tight
Lens: thin, slightly refracts
What are neurotransmitters
Chemicals that diffuse across a synapse to another neurone to trigger the next electric impulse
What are neurotransmitters
Chemicals that diffuse across synapses and bind to receptors in next neuronetk trigger a electrical impulse on next neurone
Female sex hormone
Oestrogen
Male sex hormone
Testosterone
What are the main 4 hormones that control the mensturalcycle
- FSH
- oestrogen
- LH
- progesterone
What does FSH do
- stimulates the maturing of an egg
- stimulates the production of oestrogen
What does oestrogen do
- inhibits FSH release
- stimulates LH release
- repairs uterus lining
What does LH do
- stimulates ovulation (release of an egg)
What does progesterone do
- maintains uterus lining
- inhibits both FSH and LH release
Name the 4 stages of the menstural cycle
- Mensturalation
- Uterus lining building back up
- Ovulation
- Uterus lining maintained ready for arrival of fertilised egg, if no egg cycle starts again
