B5 Homeostasis & Response Flashcards
(21 cards)
Homeostasis
Regulation of conditions maintaining a stable internal environment in response to external stimuli
Negative Feedback
Homeostasis mechanism that maintains stable level of something: if too high, reduces it, if too low high, increases it
Nervous System
Receptor -> Sensory Neuron -> CNS (relay neuron) -> Motor Neuron -> Effector
Synapses
At the end of each neuron, electric impulses cause neurotransmitters to be diffused across the synapse to the next neuron
Cerebral Cortex
Consciousness, intelligence, memory
Cerebellum
Balance, muscle coordination
Medulla
Unconscious activities such as heart rate and breathing
Hypothalamus
Homeostasis (body temp regulation etc.), sending signals to pituitary gland
Pituitary Gland
Releasing hormones
Studying the brain
Electrical stimulation to correspond parts to movements
Scanning the brain with CT (damage) MRI, PET (brain activity)
Studying brain damage
Why brain issues are difficult to treat
Wide range of brain issues
Brain is fragile, complex and contained within skull
Adaptation of Cornea
No blood vessels, transparent so that light can be refracted through
Fovea
Spot with only cone cells
Retina photoreceptors?
cones for colour, rods for b&w
Iris Reflex (CCC)
constriction of iris when circular muscles contract and radial muscles relax
dilation of iris when circular muscles relax and radial muscles contract
Accomodation (CCC)
for close objects, ciliary muscles contract and suspensory ligaments slacken making the lens fatter so that more refraction occurs
for far objects, ciliary muscles relax and suspensory ligaments are pulled taut making the lens less fat so less refraction occurs
Hyperopia & causes
Lens does not refract enough so the image forms behind the retina due to ligaments losing elasticity, eyeball to short, cornea not curved enough
Hyperopia fix
convex lens
Myopia & causes
Lens refracts too much so image forms in front of retina due to eyeball being too long, cornea too curved
Myopia fix
concave lens
