the nervous system Flashcards
(21 cards)
what does “CNS” mean?
central nervous system
what is the central nervous system and what does it do?
made of brain and spinal cord. made of specialized cells that communicate by electrical signals.
what does the brain do?
central command organ. receive all bodies impulses.
what does the spinal cord do?
allows the brain to communicate with your body.
PNS?
connects CNS to rest of the body.
PNS main parts?
1) sensory part
2) motor part
brain’s main 3 parts?
1) cerebrum
2) cerebellum
3) brain stem
cerebrum?
1) largest part of brain
2) thought processer
3) stores memories
4) feel hot/cold
5) controls 5 senses
cerebellum?
1) second largest
2) control of coordination
3) processes information from body
brain stem?
1) connects brain to spinal cord
2) has medulla
what is medulla?
1) controls involuntary processes — blood pressure, body temp, heart rate, involuntary breathing
what is the spinal cord made of?
1) nerves bundled together by blood vessels and connective tissue
2) surrounded by protected bone called vertebrae
list sensory organs?
1) eyes
2) ears
3) mouth
4) nose
5) skin
signals through the nervous system
information from the environment is received and translated into electrical signals by the nervous system.
the impulses from the brain are carried by special cells known as neurons.
glial cells protect and support neurons.
there are more glial cells in your brain than neurons.
neuron parts and functions
cell body – is the core section of the neuron. responsible for creating impulses from information received from dendrites.
a dendrite – is a usually short, branched extension of the cell body. a neuron may have one or more dendrites. they feed information from cells to the cell body.
the axon – a long or short extension from the cell body. A neuron has only one axon that carries impulses away from the cell body.
the axon terminal – is at the end of the axon. It’s where a signal is changed from an electrical signal to a chemical signal known as a neurotransmitter.
eye parts:
the cornea – A clear membrane covering the front of the eye.
the pupil – An opening that admits light.
the retina – A layer of sensory receptor cells (rods and cones) that change light into electrical impulses.
the lens – focuses light rays onto the retina.
touch
the skin is packed with many sense receptors that respond to different sensations (awareness) like a tap on the shoulder, pressure, temperature, pain, and vibration.
hearing
the sensory cells of the ears turn sound waves into electrical impulses that travel to the brain. The ears also help maintain balance.
the eardrum or the tympanic membrane separates the outer ear from the middle ear. sound waves cause the eardrum to vibrate. the vibrations are translated by receptors.
taste
the tongue is covered with taste buds that contain taste cells that respond to signals in dissolved molecules in food.
basic tastes: savory, salty, sweet, sour, bitter
smell
the sense organ for smell is the nose. receptors for smell are located in the upper part of the nasal cavity.
what is nerve damage?
can stop transmission of signals to and from the brain, causing cells or muscles to stop working or a loss of feeling in the area supplied by the nerve.
