NERVOUS SYSTEM (3) Flashcards
nervous system
specialized for processing info and sending messages from one part of the body to another
central nervous system (CNS)
consists of the brain and the spinal cord
peripheral nervous system (PNS)
consists of nerves
neurons
nerve cells that transmit impulses
neuroglia
support and nourish the neurons (help neurons)
neuron structure: cell body
contains nucleus and other organelles
neuron structure: dendrites
receive signals from sensory receptors or other neurons
neuron structure: axon (nerve fiber)
conducts nerve impulses away from the cell body
the myelin sheath
a lipid covering on long axons that acts to increase the speed of nerve impulse conduction, insulation, and regeneration in the PNS
schwann cells
neuroglia that makes up the myelin sheath in the PNS (helps speed it up)
saltatory conduction
conduction of the nerve impulse from node to node
action potential
rapid changes in membrane carried down the axon (allows the nerve impulse to occur)
depolarization
lets Na+ in
repolarization
lets K+ out
synapse
transmission of impulse across a synaptic cleft from the presynaptic membrane to the postsynaptic membrane (GAP)
integration
is the summation of the inhibitory and excitatory signals received by a postsynaptic neuron (end result of what your body is going to do)
meniges (CNS)
three membranes covering and protecting the spinal cord and brain
cerebrospinal fluid (CFS) (CNS)
cushions and protects the CNS
gray matter (CNS)
cell bodies and short nonmyelinated fibers
white matter (CNS)
contains myelinated axons
cerebrum
- frontal lobe- primary motor area and conscious thought
- temporal lobe- primary auditory, smell, and speech area
- parietal lobe- primary somatosensory and taste area
- occipital lobe- primary visual area
wernicke`s area
helps us understand both written and spoken word
broca`s area
adds grammatical refinements and directs the primary motor area to stimulate the appropriate muscles for speaking
limbic system
emotions
brainstem (3)
- midbrain- acts as a relay station for impulses passing between the cerebrum and the spinal cord or cerebellum (also a relax center)
- pons- regulates breathing rate and has reflex centers concerned with head movements in response to visual and auditory stimuli
- medulla oblongata- reflex centers for regulating heartbeat, breathing, and blood pressure
somatic and autonomic
PNS is divided into 2 systems
autonomic system
regulates activity of the cardiac and smooth muscles and the glands
sympathetic division
coordinates the body for action “fight or flight”
- speeds up metabolism
- speeds up heart action and breathing
parasympathetic divison
brings about the responses we associate with a relaxed state
- slows down metabolism
- slows down heart action and breathing
somatic system
serves the skin, skeletal muscles, and tendons
reflex arch
- sensory neuron (to spinal cord glands)
- interneuron (spinal cord)
- motor neuron (from spinal cord)
- effector (to muscles)
resting potential *negative charge
1. Na+ gates open up = depolarized (cell becomes more +) 2. Na+ gates close = repolarize (cell becomes more -) 3. K+ gates open 4. K+ gates close 5. Na/K pump
semantic
skeletal muscle and voluntary
autonomic
- involuntary, glands, smooth muscle, cardiac muscle
- either sympathetic or parasympathetic
