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There is a break down of what after a muscle contraction?

Ach using acetylcholinesterase enzyme to relax muscle

Motor Neuron

a neuron conducting impulses outwards from the brain or spinal cord

Sensory Neuron

a neuron conducting impulses inwards to the brain or spinal cord

Associative Neuron

Carries messages from the Sensory Neuron to the Motor Neuron


Most common Type of Neuron

Over all Purpose of Nevous System

-Response to internal and external stimuli
-Overall body homeostasis
-Voluntarily controlled motions and locomotions
-involuntary control of viseral actions (organs)
-protection through use of reflex arcs
-thought processes, reasoning , interpretation of nervous system stimuli impulses and motor reactions
-close association with endocrine glands fr impulse passage and homeostatsis.

Individual neurons carry what in one direction from dendrites receiving to axon terminal release using fraded andaction potentials, Na+ and K+ ion pumps?

Electrochemical Impulses

Efferent Pathway

Carry information from central cervous system to periphery with the intent of carrying out a response. Motor neurons.

Afferent Pathway

Pathway leaving the sensor and going to the control center; Sensory Neurons

Are neurons connected?

Neurons are NOT connected; they are close and neurotransmitters such as ACH or Norepinephrine are sent within the synapsis

Unipolar Neuron

cell body with single process that divides into two branches and functions as an axon. (L) found in ganglia outside the brain and spinal cord

Bipolar Neuron

Two Processes; A neuron with a single axon and a single dendrite, often projecting from opposite sides of the cell body. Bipolar neurons are typically associated with sensory organs; an example is the bipolar neuron in the retina of the eye. - note that one axon may innervate many different muscles, or other things.

Multipolar Neuron

Three or more processes; cell body with many processes one of which is an axon, the rest dendrites. (L) brain and spinal cord.

Purpose of Myelination

Speed of impulse passage and difference to unmyelinated; Increases the speed of transmission of nerve impulses
Myelination is an insulator as plastic around electrical wire

White Matter

Regions of the brain and spinal cord containing dense collections of myelinated fiber

Grey Matter

Contains mostly nerve cell bodies and unmyelinated fibers

Unmyelinated Fibers

Conduct umpulses quite slowly; Dendrites are always unmyelinated

Neurons/ Nerve Cells

Highly spcialized cells that conduct messages in the form of nerve impulses from one part of the body to another


type of neuroglial cell that produces myelin in the CNS

Schwann Cells

Supporting cells of the peripheral nervous system responsible for the formation of myelin.

Central Nervous System CNS

consists of the brain and spinal cord; the dorsal body cavity; it inteprets sensory input and dictates motor responses based on reflexes, current conditions and past experience

Peripheral Nervous System PNS

The part of the nervous system outside the CNS; consists mainly of the nerves(bundles of axons) that extend from the brain and spinal cord.

The ____ the nerve- the faster the impulse


The all or none phenomena means what?

It either happens completly or it doesn't happen at all; If the number of Na+ ions entering the cell is too low to achieve threshold, no AP will occur.


Concentrations of cell bodes of several neurons in one place to amplify impulse as apssed-outside CNS

What is the single longest nerve

Sciatic nerve down past hip inot leg- of sacral plexus

Divisions of CNS

Voluntary and Involuntary systems

Divisions of PNS

Somatic and Autonomic (called enteric) they further separate into Sympathetic and Parasympathetic

Includes nervous 31 pairs of body nerves and 12 pair of crainial nerves

Autonomic NS and glands of somatic cells, glial cells, associative neruons, interneurons

What is a Reflex?

an automatic instinctive unlearned reaction to a stimulus

Microglia and its role

smallest neuroglial cells; phagocytic cells that enculf cellular debris, waste products and pathogens. increase in number as a result of infection or injury

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