B10 - human nervous system Flashcards
What do receptor cells do, with examples
Sense a change (touch, light, temperature)
What is homeostasis
Controlling the internal environment of the human body
What nerve transmits signals from receptors to CNS
Sensory neurone
What nerve transmits signals from CNS to effectors
Motor neurone
What is the CNS
Central nervous system, spinal chord and brain
What do effectors do
Move or change something (muscles, glands)
What is the difference between a normal action and a reflex action
In a reflex action the signal doesn’t go to the brain, it goes through a relay neurone from the sensory neurone straight to the motor neurone, reflex is faster, don’t think
What is a synapse
The connection between two neurones
How does a synapse work
Neurotransmitters diffuse across the gap and are deflected by receptor cells that transmit the signal
Why do we need synapses
To slow down actions
What are the 4 main parts of the brain and functions
Cerebral cortex - intelligence, memory
Cerebellum - movement
Medulla - unconscious (breathing, heart rate)
Pituitary gland - controls other glands
How and why does the pupil dilate
Dilates when circular muscles relax and radial muscles contract, to let more light in when dark
What happens when circular muscles relax
Pupils dilate
What happens when circular muscles contract
Pupils get smaller
What happens when radial muscles relax
Pupil gets smaller
What happens when radial muscles contract
Pupil dilates
How and why does the lens flatten and fatten
Flattens - long distance vision, suspensory ligaments tighten and ciliary muscles relax
Fattens - short distance vision, suspensory ligaments loosen and ciliary muscles contract
What happens when the suspensory ligaments tighten
Lens flattens
What happens when the suspensory ligaments loosen
Lens fattens
What happens when the ciliary muscles relax
Lens flattens
What happens when the ciliary muscles contract
Lens fattens
Where are the radial muscles
The muscle in the eye that are radiuses of the eye (from pupil to outside of eye)
Where are the circular muscles
The muscles in the eye that are concentric circles around the pupil
Where is the suspensory ligament
The ligament pulling the lens from the sides to the side of the eye
Where is the ciliary muscle
The muscle around the outside of the eye near the lens
What is myopia
The eye is too long so light focuses in front of retina (short sighted)
What is hyperopia
The eye is too short so light (would if there was nothing in the way) focus behind retina (long sighted)
What lens do you need for myopia and hyperopia respectively
Myopia - concave
Hyperopia - convex
