A&P 2

• Central Nervous System
• Brain and spinal cord

Peripheral Nervous System

Nerves and Ganglia (groups of neuron cell bodies outside the cns)

towards brain

sensory NS (visceral and somatic)

Away from brain (It takes EFFORT to move muscles)

Motor NS

Soma = Body

Voluntary NS

Automatic NS (cardiac m etc)

Visceral NS

Fight or Flight

Initiates Stress response

rest and repose

operates during normal relaxed conditions

1-Sensory (Afferent)

2-Integrative (CNS) Interneurons

3-Motor (Efferent)

Neurons-amitotic-cells that transmit the action potentials (nerve impulses)

Neuroglia- mitotic-cells that support/protect and nourish the neurons

1-Soma Cell body of the neuron

2-Axon-process that carries the impulse away from the cell body (axon/away)

3-Dendrite-process that carries impulse towards cell body

1-Multipolar -1 axon many dendrites

2-Bipolar- 1 axon and 1 dendrite -rare-

3-Unipolar- 1 process off cell body that splits into axonic and dendritic processes

4-anaxonic- many short processes

1-Excitability- ability to recieve and respond to a stimulus

2- Conductivity- ability to transmit an impulse

-70 mV

1-Depolarization- when the Na+ gates open and depolarized from -70mV to 0mV

2-Reverse Polarization-So much Na+ that for instant membrane is positive

3-Repolarization- when K+ gates open and cell is back to -70mV

4-Sodium-potassium pump- cell being reset

Absolute Refractory Pd- pd of time cell ABSOLUTLEY cannot fire because it hasnt been reset enough

Relative refractory Pd- pd of time it takes a larger than normal stimulus to fire b/c cell is only partially reset

The minimum stimulus needed to achieve an action potential

Nerves fire completely and as hard as they can.....there are NO weak nerve firings

Myelin and PNS

gaps in myelin sheath

Type of conduction in UNMYELINATED nerve fibers

LEAPING conduction in myelinated fibers

Nerve cell membrane

region of communication between 2 neurons

fluid filled space between pre and post synaptic neurons

reaction between neurotransmitter and receptor depolarizes post synaptic membrane- EXCITES nerve firing

Reaction between neurotransmitter and receptor-hyperpolarization of membrane- INHIBITS nerve firing

1-Single series- 1 neuron synapses with another single neuron

• 2-Divergence circuit- 1 neuron synapses with multiple neurons (DIVERGES)
• 3-Convergence Circuit- many neurons synapse with a single neuron. (CONVERGES)

1-Receptor

2-afferent neuron-sensory

3-interneuron-cns

4-Efferent neuron-motor

5-Effector

Random Acts Include Empathetic Elephants

individual axon or dendrite

CT covering surrounding single nerve fiber and its neurilemma

bundle of nerve fibers

ct covering surrounding fascicle

CT covering surrounding entire nerve

Yes...because of high demand for energy