Nervous system.txt

Concept that implies a state of "normalcy" in the body; it is reached when things are operating within normal biological limits.

• External environment
• Internal environment

• Central Nervous System
• Brain and spinal cord
• Does not include cranial and spinal nerves

Brain and spinal cord (CNS) involved in analysis of sensory information and problem solving

The CNS "decides" how to respond and does so through muscle contraction and glandular secretion

• Voluntary
• 12 pairs cranial nerves; 31 pairs spinal nerves
• Somatic nervous system (SNS)
• Autonomic nervous system (ANS)

carry impulses from receptors to CNS

carry impulses from CNS to effectors skeletal muscle only

Involuntary

carry impulses from visceral receptors to CNS

carry impulses from CNS to visceral effectors - smooth muscle, cardiac muscle and glands

has both CNS and PNS components

Transmits impulses from skin fascia, joints and skeletal muscle to CNS

Transmits impulses from visceral structures to CNS

Has both CNS and PNS components

Voluntary control of skeletal muscles

Involuntary control of visceral effectors

Nucleus and surrounding cytoplasm of a neuron (excluding it's dendrites and axon)

Contained in the cytoplasm

contained in the nucleus

Any extension or process from cell body

Neuron process that conducts nerve impulses away from the cell body "output"

• Neuron processes that conduct information to the cell body "input"
• Form receptors at ends of sensory neurons

Clumps of yellow pigment; increases with age; may be produced by lysosomes

Consist of both free and attached (bound) ribosomes; make proteins for repair and neurotransmitters

Origin of axon

Microtubules that form the cytoskeleton

Intermediate filament aggregates that form neurofibrils

Form networks; support axons and dendrites

Cytoplasm of axon; has mitocondria; no nissl bodies

Plasma membrane of axon

Side brances of axon

First end branches of axons

Supply several to 100,000 muscle fiber

contain neurotransmitters

about 40 - 50 plus known