A&P - Nervous System

Central Nervous System (CNS) - Parts

brain and spinal cord

Peripheral Nervous System (PNS) - Parts

All nerves outside the brain and spinal cord

Neuroglia

cells that support and protect neurons

Astrocytes (CNS)

maintain blood brain barrier, control blood-brain barrier

Ependymal cells (CNS)

produce cerebrospinal fluid

Microglia (CNS)

Remove cell debris, wastes, and pathogens by phagocytosis

Oligodendrocytes (CNS)

produces myelin for CNS axons

Schwann cells (PNS)

produces myelin for PNS

Dendrites

Branchlike parts of a neuron that are specialized to receive information, sending it down the axon

cell body of neuron

contains nucleus and organelles

Axon

single long fiber extending from the cell body; it carries outgoing messages

synapsis

the space where two neurons come together

synaptic cleft

The narrow gap that separates the presynaptic neuron from the postsynaptic cell.

sensory (afferent) neurons

neurons that carry incoming information from the sensory receptors to the brain and spinal cord

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

motor (efferent) neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Effectors

body parts that respond to motor neurons

resting membrane potential

the electrical charge of a neuron when it is not active, -70mV

action potential

a brief electrical charge that travels down an axon, changes -70mV to -55mV, then to +30mV

Repolarization

Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell, +30mV to -70mV

saltatory conduction

Rapid transmission of a nerve impulse along an axon, impulse jumping from one node of Ranvier to another

Neurotransmitters

Chemicals that transmit information from one neuron to another

excitatory neurotransmitters

excite the next cell into firing

inhibitory neurotransmitters

inhibit the next cell from firing

cerebrospinal fluid (CSF)

plasma-like clear fluid circulating in and around the brain and spinal cord, forms a watery cushion to protect the brain

blood-brain barrier

a filtering mechanism that carry blood to the brain and spinal cord tissue, blocking the passage of certain substances

reflex arc

A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus, often without conscious brain involvement

reflex

a simple, automatic response to a sensory stimulus

autonomic reflexes

digestive and smooth muscle regulation, heart and blood pressure regulation

somatic reflexes

activation of skeletal muscles