Anatomy: Organization of the Nervous System

Function of nervous system

Coordinate the bodies systems by receiving and sending information; maintaining homeostasis

Sensory input

gathers information from receptors in the body

Integrative

Determines where information is sent and what to do about it

Motor output

Responds to signals, brings about a response

Central Nervous System (CNS)

Brain & Spinal cord

Peripheral Nervous System (PNS)

31 pairs of spinal nerves, 12 pairs of cranial nerves

Sensory (affarent)

Convey impulses to the CNS from sensory receptors all over the body

Motor (efferent)

Carries impulses from CNS to effector organs (muscles and glands) —— Broken up into somatic and autonomic divisions/bring about a motor response

Somatic Nervous System

Voluntarily control our skeletal muscles — EXCEPTION: stretch reflex

Autonomic Nervous System

Regulates events that are autonomic and involuntary —— Activity of smooth and cardiac muscles and glands/consists of sympathetic and parasympathetic

Parasympathetic

Rest & digest

Sympathetic

fight or flight

Neurons

Nerve cells/ cells specialized to transmit messages

Cell body (MAJOR REGIONS OF NEURONS)

Nucleus and metabolic center of the cell —- Anatomy: Nucleus, large nucleus

Processes (MAJOR REGIONS OF NEURONS)

Fibers that extend from the cell body

Dendrites (EXTENSION OUTSIDE THE CELL BODY)

conduct impulses towards the cell body

Axons (EXTENSION OUTSIDE THE CELL BODY)

Conduct impulses away from the cell body — Axons end in axonal terminals

Axonal terminals

Contain vesicles with neurotransmitters/ Separated from the next neuron by a gap

Synaptic Cleft

Gap between adjacent neurons

Synapse

Junction between nerves/where two neurons meet

Neurological cells

Support for neurons

Myelin shealth

Formed in jelly-roll like fashion, provides insulation for the axon

Nodes of ranvier

Gaps in myelin shealth along the axon

Myelinated (White matter)

Myelinated axons

Unmyelinated (Grey matter)

Unmyelinated areas

Microglial cells

Immune function; digest debris, kills bacteria

Oligodendrocyte

make myelin sheath that provides insulation around the axons

Astrocytes

connect blood vessels to neurons connect to blood vessels

Ependymal cells

Forms membranes around tissue

Schwann cells

produces insulation for the axon/ form the insulating myelin sheath around the neurons in the PNS (same function as oligodendrocytes, which are found in the CNS)

Sensory (affarent) NEURONS

carry impulses from the sensory receptors — untaneous sense organs/ proprioceptors detect stretch or tension

Interneurons (asssociate neurons)

found in neural pathways in the central nervous system — connect sensory and motor neurons/ type of neuron that joins motor and sensory neurons together

Motor (efferent) NEURONS

carry impulses from the central nervous system

Multipolar neurons

Many extensions from the cell body/ type of neuron with many processes coming from it

Bipolar neurons

one axon and one dendrite

Unipolar neurons

have a short single process leaving the cell body

Neurotransmitters

Chemical messengers stored within synaptic vesicles in the axon terminal.

Structural classification

Central nervous system, Peripheral Nervous System

Functional Classification

Sensory/afferent, Motor efferent —> Autonomic, Somatic