The nervous system (function and transmission)

nervous system

a network of nerves that transport nerve impulses throughout the body

cell body

contains the nucleus and organelles that keep the neuron functioning

dendrites

receives cells and carry them to them toward the cell body

axon

sends signals away from other cells

myelin sheath

covers many axons, helps nerve impulses travel faster

Nodes of ranvier

gaps of myelin sheath, allows signals to move quickly along the axon

neuroglia

provides support and nutrition, maintains homeostasis, and forms the myelin sheaths that covers the neurons of the CNS

when a neuron is resting

the inside is more negative than the outside

depolarization

when sodium moves into the cell

repolarization

when potassium moves out of the cell

electrical signal

Inside a single cell

chemical signal

between two cells

synapse

small gaps between cells where neurons pass information to each other

neurons divide

false

chematolysis

the swelling of a neuron because of injury

spinal cord

a long soft bundle of nervous tissue that connects the brain to the rest of the body

sensory information

travels up the spinal cord to the brain, ex; pain, touch, temp

motor information

travels down from the brain to the muscles

sensory neurons

carry signals from the skin eyes and ears to the cns

sensory neurons (afferent neurons)

carries signals from the skin, eyes, and ears to the cns

motor neurons (efferent neurons)

carries signals from the cns to the muscles and glands

somatic motor neurons

control voluntary skeletal muscle movement

autonomic motor neurons

control involuntary muscle movement (like heart rate and digestion)

interneurons

found within the cns connecting sensory neurons to motor neurons

risk factors for tbi

caused by an external mechanical force, so a jolt, blow, or bump to the head

pns (peripheral nervous system)

apart of the nervous system outside of the brain and spinal cord, connects the cns to the rest of the body by carrying nerve impulses back and fourth

the motor part of the pns

carries out voluntary and involuntary actions

sympathetic

fight or flight

parasympathetic

rest and digest

how do neurons die

through apoptosis or necrosis

cerebral palsy

group of disorders resulting from damage of the upper motor neurons before, after, or during birth

Multiple Sclerosis

a chronic autoimmune disease of the cns that attacks the myelin sheaths

ISCT (incomplete spinal cord transection)

occurs when trauma damages the spinal cord, disrupting the the transmission of sensory and motor nerve impulses before the level of injury

damage to white matter

effects the conduction of nerve signals

damage to gray matter

leads to loss of motor neurons and interneurons

acs (anterior cord syndrome)

front part damage from flexion injury or arterial blood loss, loss of motor, pain, and temp below injury

CCS (central cord syndrome)

center damage common in cervical area from hyper extension

parkisons disease

chronic progressive neurological disorder caused by degeneration of dopamine producing neurons

pain

a common but complex sensation and an unpleasant experience linked to tissue damage and emotional response

nocireceptors

responds to potential tissue damage

somatic senses

touch, vibration, pressure, and pain

gate control theory

a gate in the spinal cord that modulates pain and signal transmission in the brain

neuomatrix theory (1990)

says that pain is a multidimensional experience that is produced by neurosignature pattern of the brain

neuropathic pain

originates in the cns, does not activate specific nociceptive receptors, does not follow typical transmission pattern of impulse conduction (burning, tingling)

referred pain

pain is felt in a different part of the body than where it originates

visceral pain

originates from internal organs caused by inflammation, ischemia, and injury

somatic pain

originates from deeper tissues like the muscles, joint, ligaments, and tendons