intro to nervous system Flashcards
what two systems make up the nervous system?
the peripheral nervous system and the central nervous system.
The CNS comprises of?
The brain and spinal chord
The PNS comprises of?
The nerves that extend from the CNS into the body. (12 cranial nerves and the 31 spinal nerves).
What are afferent nerve fibres?
They bring sensory information to the CNS from the periphery for processing.
What are efferent nerve fibres?
They take motor information from the CNS to the periphery.
Cranial nerve 1- the olfactory nerve? sensory
Located in the olfactory bulb of the nose, responsible for our sense of smell.
Cranial nerve 2- the optic nerve? sensory
responsible for our sight
Cranial nerve 3- the oculomotor nerve? motor, mixed
responsible for control certain eye muscles, focusing of the lens and proprioception- moving our eyes with our head automatically.
cranial nerve 4- the trochlear nerve? motor, mixed
responsible for the control of most eye muscles and proprioception.
cranial nerve 5- the trigeminal nerve? mixed
motor to chewing muscles (buccinator, temporalis and masseter).
3 branches: (all sensory)- to the mouth
opthalmic- sensory to cornea, skin of nose and scalp
maxillary-sensory to upper teeth, lips and upper gums
mandibular- sensory from teeth, lips and lower gums
cranial nerve 6- the abducens nerve? motor
Responsible for eye muscles and proprioception
cranial nerve 7- the facial nerve? mixed
sensory to the taste buds
motor to the muscles of facial expression/saliva excretion
cranial nerve 8- the vestibulocochlear nerve? sensory
innervates the ampulla, vestibule and cochlear to allow hearing and also balance and position.
cranial nerve 9- the glossopharyngeal nerve? mixed
motor to pharynx muscles (swallowing)
sensory to pharynx, middle ear and carotid sinus-(needed for BP reflex).
cranial nerve 10- the vagus nerve? mixed
parasympathetic headquarters
motor to the muscles of the pharynx and larynx
sensory impulses from taste buds
cranial nerve 11- the spinal accessory nerve? mixed
motor to the trapezius and sternocleidomastoid muscles (enables neck and head turning)
sensory to skin over these muscles
proprioception
cranial nerve 12- the hypoglossal nerve? mixed
motor to tongue muscles and proprioception
What are the main parts of a neuron?
Cell body:(processing)
axon: propagating action potentials
dendrites: exchange of action potentials between neurons
Explain the reflex arc, with afferent, efferent and interneurons.
A message from the periphery, sensory nerves is sent via the afferent neurons.
The interneurons relay the mesasge within the brain.
Then the efferent neurons transport the new message back to the periphery to control the muscle.
Grey matter consists of….
cell bodies and dendrites
white matter consists of…
myelinated axon bodies
What are astrocytes?
Astrocytes:
star-shaped cells that hold the neurons together for structural support.
They also make up the blood brain barrier, and carry out general neuronal maintenance in the brain.