Nervous System Flashcards
What is the central nervous system composed of?
Brain & spinal cord
What is a sensory pathway?
Receive info from the environment and send message to the CNS
What is a motor pathway?
Take directions from the central nervous system and send messages to the effectors (muscles and glands)
What’s the difference between somatic and autonomic?
somatic pathways lead to voluntary muscles (ex- move leg muscles to run)
Autonomic pathways lead to involuntary muscles (ex-heart muscles and smooth muscles in the stomach)
What can autonomic be broken into?
Sympathetic and parasympathetic
What’s the difference between sympathetic and parasympathetic?
Sympathetic stimulates tissue (ex-heart rate increases)
Parasympathetic system inhibits tissue (ex-heart rate decreases)
What is a Dendrite?
Receive info from specialized receptors. Conducts impulses towards the cell body. Up to 4000 per neuron
Define cell body
Contains many organelles and are often found grouped together with other cell bodies
Define axon
Carries nerve impulses toward other neurons or to effectors. Can be over 1m long! Made up of cytoplasm
Define myelin sheath
Coat of fatty protection which acts as insulation for neurons. Created by Schwann cells and prevents the loss of charged ions.
What happens if there is no myelin sheath?
The transfer slows down or does not transfer
Define Neurilemma
All nerve fibres found within the PNS have neurilemma. It is a delicate outer membrane of axons with myelin sheath.
It promotes regeneration of damaged neuron
not all nerves have neurilemma
Define Nodes of Ranvier
Gaps between the myelin sheath. Causes nerve impulses to “jump” from one node to another. Creates fast transmission of nerve impulse
Define synaptic knob
Swelling at the end tip of axon branches. Contains chemical-contains vesicles and mitochondria
What is the peripheral nervous system made of?
Sensory & motor neurons
