Nerve Tissue

Function of the nervous system?

1)Integrate and interperet stimuli
2) Direct an appropriate response

Name the 2 parts of the Nervous System?

1 Central nervous system--CNS
2 peripheral nervous system--PNS

Afferent neurons (Sensory Neurons)

Nerve processes that carry info from the PNS in muscles and glands to the CNS
-To CNS

Efferent neurons (Motor Neurons)

Brain sends reponses to muscles and glands
-From CNS

Sensory Neurons (Afferent pathway)

transmit sensations from PNS to CNS

Motor Neurons (Efferent pathway)

*Elicit a response
Transmit impulses from CNS to muscles and other organs to elicit a response

What are the 2 types of motor neurons?

1 somatic motor neurons
2 autonomic motor neurons

Somatic motor neurons

carries impulses from the CNS to the voluntary muscles
*ex. skeletal muscles of hand

Autonomic motor neurons

Carries impulses from the CNS to the involuntary muscles and all glands.
*Cardic/Smooth muscles

What are the cells of the nervous system?

1 Neurons
2 Glial

Neurons

Composed of a cell body, dendrites, and an axon
*we are born with all the neurons we'll ever have & some are dormat

What do Glial cells do?

1)Provide structural support
2)nourishment for the neurons

Perikaryon

The nerve cell body. Contains the nucleus and organelles

Cytoplasmic extensions includes what?

1) Dendrites
2) Axon

Dendrites

receive stimuli and conduct impulses toward the cell body

Axon

Conduct impulses away from the cell body
*one way flow of info

Direction of impulse transmission within 1 neuron:

Dendrite*Cell body*Axon

4 types of Glial Cells

1 Astrocyte
2 Microglia
3 Oligodendrocyte
4 Schwann cell

What are schwann cells made of?

Myelin, which forms Myelin Sheath on the outside of an axon.

Gaps between adjacent schwann cells are called?

Nodes of Ranvier

Astrocyte-CNS

-Star shaped
-Provides nutrition to neurons

Microglia-CNS

Phagocytic scavenger cell

Oligodendrocyte-CNS

produces myelin
Myelin sheath increases the speed of electrical conduction

Degeneration of the myelin sheath results in what?

Multiple Sclerosis

Schwann Cells

Production of Myelin sheath
*responsible for increasing the speed of conduction of an impulse along a neuron

Synapses

Junctions between 2 neurons or between a neuron and its effector (muscle or gland)

An impulse is transmitted from the ______ of one neuron to the ______ of another neuron with the aid of _____________.

Axon, dendrite, neurotransmitter

Direction of an impulse transmission between 2 neurons?

Axon* Dendrite

Types of Neurons?

1) Multipolar
2) Bipolar
3) Unipolar
4) Interneurons

Multipolar

Have many dendrites arising from the cell body
*Most

Bipolar

One process emerges from each pole of the cell body

Unipolar

One processes that divides into 2 branches; 1 goes to the PNS & 1 goes to the CNS

Interneurons

Lie with in the CNS, Receive and link sensory and motor impulses to bring about the appropriate response

Neurotransmitters

Contained in synaptic vesiscles in axon only. This ensures that nerve transmission is in one direction only.

Some types of Neurotransmitters?

Acetylcholine
Serotonin
Dopamine
Norepinephrine

What is the resting potential of a neuron?

-70mV

An action potential occurs when there is a ____________ of the membrane.

Depolarization