Outline of the Nervous System
NERVOUS SYSTEM OUTLINE
I. Nervous System = 2 Parts
A. Central Nervous System (CNS)
1. Brain
2. Spinal Cord
B. Peripheral Nervous System (PNS)
1. Nerves to parts of the body
2. Nerves from parts of the body
C. Functions
1. Sensory
a. receptors for stimuli (receive stimulus)
b. peripheral nerves (carry impulses to CNS)
c. activities monitored
1) light intensity (visual)
2) sound intensity (auditory)
3) temperature
4) oxygen concentration
5) internal fluid conditions
2. Motor
a. peripheral nerves (carry impulses from CNS)
b. effectors (muscles & glands)
3. Integration (CNS)
a. create sensations (awareness)
b. add to memory
c. help produce thoughts
d. make decisions (conscious & subconscious)
4. Importance = maintain homeostasis
II. Nerve Tissue
A. Neurons (structural & functional units of nervous system)
B. Neuroglial Cells (accessory cells: support neurons)
1. Astrocytes (star shaped cell)
a. found between neurons and blood vessels
b. provide nutrition
c. support
d. form scar tissue after brain tissue injury (multiply)
2. Oligodendrocytes
a. smaller than astrocytes with fewer processes
b. found along neurons
c. form myelin sheath (brain and spinal cord neurons)
3. Microglia
a. very small cells with even fewer processes
b. found throughout CNS
c. phagaocytosis
d. increase in numbers during inflammation
4. Ependymal Cells
a. cube to columnar shaped cells
b. found lining ventricles & central canal of spinal cord
c. cover choroids plexuses in brain
III. Nerve Impulse Conduction
A. Resting Potential
1. positive charge outside
a. high sodium ion concentration 1) sodium pump
2. negative charge inside
a. phosphate & sulfate ions
b. negatively charged proteins
c. high potassium concentration
1) potassium pump
3. potential difference = -70 mV
B. Potential changes
1. –70 mV to 0 = depolarization
2. higher than –70 mV = hyperpolarizing
C. Action Potential occurs when Threshold Potential achieved
1. causes
I. Nervous System = 2 Parts
A. Central Nervous System (CNS)
1. Brain
2. Spinal Cord
B. Peripheral Nervous System (PNS)
1. Nerves to parts of the body
2. Nerves from parts of the body
C. Functions
1. Sensory
a. receptors for stimuli (receive stimulus)
b. peripheral nerves (carry impulses to CNS)
c. activities monitored
1) light intensity (visual)
2) sound intensity (auditory)
3) temperature
4) oxygen concentration
5) internal fluid conditions
2. Motor
a. peripheral nerves (carry impulses from CNS)
b. effectors (muscles & glands)
3. Integration (CNS)
a. create sensations (awareness)
b. add to memory
c. help produce thoughts
d. make decisions (conscious & subconscious)
4. Importance = maintain homeostasis
II. Nerve Tissue
A. Neurons (structural & functional units of nervous system)
B. Neuroglial Cells (accessory cells: support neurons)
1. Astrocytes (star shaped cell)
a. found between neurons and blood vessels
b. provide nutrition
c. support
d. form scar tissue after brain tissue injury (multiply)
2. Oligodendrocytes
a. smaller than astrocytes with fewer processes
b. found along neurons
c. form myelin sheath (brain and spinal cord neurons)
3. Microglia
a. very small cells with even fewer processes
b. found throughout CNS
c. phagaocytosis
d. increase in numbers during inflammation
4. Ependymal Cells
a. cube to columnar shaped cells
b. found lining ventricles & central canal of spinal cord
c. cover choroids plexuses in brain
III. Nerve Impulse Conduction
A. Resting Potential
1. positive charge outside
a. high sodium ion concentration 1) sodium pump
2. negative charge inside
a. phosphate & sulfate ions
b. negatively charged proteins
c. high potassium concentration
1) potassium pump
3. potential difference = -70 mV
B. Potential changes
1. –70 mV to 0 = depolarization
2. higher than –70 mV = hyperpolarizing
C. Action Potential occurs when Threshold Potential achieved
1. causes