B3 Flashcards
CNS
Brain and spinal cord
Coordinate the response in other words he decides what to do about the stimulus and tells something to do it.
Send information to and affecter along and with a neurone
How do you electrical impulses travel in nerves
Electrical impulses are passed along the axon of the neurone
What is a dendrite
Branched endings of the neuron so they can connect with lots of open neurons
What is a batty myelin sheath
Act as an electrical insulator which speeds up the electrical impulse
Why is one long neuron quicker than lots of small connected neurons
Connecting with another neuron slows the impulse down Due to the connection between the two neurons called a synapse which is a very tiny gap
Synapse
Electrical impulse triggers the release of transmitted chemicals which diffuse across the gap
These chemicals bind with receptor molecules in the membrane of the next neuron this sets off a new electrical impulse
How do reflex arcs work
The sensory neuron connects to a relay neuron in the spinal-cord or an unconscious part of the brain which links directly to the right motor neurone so no time is wasted thinking
Job of cornea
Refracts light into the eye
Iris
Controls how much light enters the people
Lens
Also refracts light focusing it onto the retina
Ciliary body
Contains ciliary muscles which are attached to the suspensory ligaments they work together to alter the shape of the lens
Retina
Light sensitive part and is covered in receptors called rods and cones which detect a light
Rods
More sensitive in dim light but can’t sense colour
Cones
Sensitive to different colours but I’m not so good in dim light
Optic nerve
Carries impulses from the receptors to the brain
How do you focus on Distant objects
Ciliary muscle Relaxes which allows the suspensory ligament’s to pull tight This means less light is refracted
Long sightedness
Unable to focus on near objects because Lens is wrong shape and doesn’t bend light enough or eyeball is too short
This can be corrected with contact lens
Colourblindness
Most common form is red green colourblindness this it is caused when red or green cones in the retina are not working properly
Cerebrum
This is the alpha wrinkly bit it is responsible for things like consciousness intelligence memory and language
Hypothalamus
Involved in maintaining body temperature at the normal level also produces hormones that control the pituitary gland
Pituitary
A gland that produces many important hormones such as some of those involved in the menstrual cycle
Medulla
Controls unconscious activities like breathing and your heart rate
Cerebellum
Responsible for muscle coordination