Topic 2 - Cells and Controll Flashcards
What makes up the central nervous system?
The brain and the spinal chord
What is the spinal chord?
a long column of neurones that run from the base of the brain down the spine. ar several places down the chord, neurons branch off and connect with other parts of the body
What does the spinal chord do?
relays information between the brain and the rest of the body
What are neurons?
Nerve cells
WHat is the brain made up of?
Billions of interconnected neurons§
What is the cerebrum?
The largest part of the brain, its divided into two halfs callled cerebral hemishperes
The right hemishpere controlls the muscles on the left side and vice versa.
Different parts of the cerebrum are responsible for different things liek movement, intelligence, memory, language and vision
Cerebellum
Responsible for muscle coordination and balance
Back fo the head
Medulla Oblongata
controlls unconcious activities like breathing or heart rate
What are scanners used for?
To investigate brain function
to otherwise investigate it, youd have to cut into the brain wich is pretty risky ngl
A CT scanner
A CT scanner uses X-rays to produce and image of the brain.
A CT scan can show the main structures in the brain, but not the functions of them
if the CT shows a diseased/damaged brain with loss of function it can be
worked out.
PET scans
Fancier than Ct scans, they use radioactive chemicals to show which parts of the brain are active when the person is isnsdie the scanner
PET s are very detailed and can be used to investagate both the sturcture and the function of the brain in real time
Can show if the brain is unsusually incacitve or active
Why are problems In the CNS hard to treat?
Its hard to repair damages
Uneasy acces to repair things
Treating problems may lead to permanent damage
What do receptor cells do?
detect stimuli
What is a transmittion of neurones called?
A neurotransmittion
What is a sensory neurons function?
To carry impulses from the receptor cells to the CNS
How do sensory Neurons work?
a receptor cell impulse passes into a tiny branch called a dendrite, it is then passed along the dendron( receives) and the axon(sends out). A series of axon terminals allow impulses to be transmitted to other neurons
Why are Dendrons and axons long?
To allow fast transmittion over long distances
MYlein sheath
Electrically insulates a neuron from neighbouring neurones
Where are the receptor cells found in the eye?
in the retina
Cones
The receptor cells sensitive to the color of light, some detect red light, whilst some green or blue
Cones genrate impulses in sensory neurons, Which lead into the brain through the optic nerve, this infor is then tranferred into full color vision at the back of the cerebral hemispheres
Rods
receptor cells that detect light intensity, not color
Why is your vision less colorfull in dim ligth?
ods work weel in dim light but cones dont
Pupil
dark area in the centre of the eye
where the light enters
Iris
Colored part of eye
Can constrict the pupil or dilate it to control the light going in for strong light levels can damage the retina
What do the cilary muscles do?
alter the shape of the lens, make it fatter or thinnner to focus the light
Cornea
Clear, colorless covering that focuses light rays, bringing them together
Lens
Fine tunes focusing after cornea
Short sighted people
Light focuses infront of the retina - long eye or curved cornea
Needs a Divergins lens
Long sighted People
Light focuses behind of the retina - short eye or flat cornea
Needs a converging lens
Cataract
when protein builds up in the lens and makes it cloudy
