Human A&P Nervous System

What does the nervous system control?

Every thought, action, and emotion.

How do nervous system cells communicate?

Using electrical and chemical signals.

What are the 3 main functions of the nervous system?

• Sensory input

• Integration

• Motor output

What is sensory input?

Receptors monitor changes inside and outside the body.

What is integration?

Processing and interpreting sensory input.

What is motor output?

Activating effectors (muscles/glands) for a response.

What are the two main parts of the nervous system?

• CNS (brain + spinal cord)

• PNS (nerves + ganglia)

What is the CNS?

• Brain = integration center

• Spinal cord = sends info to/from body

What is the PNS?

• Spinal nerves, cranial nerves, ganglia

What are the PNS subdivisions?

• Sensory (afferent): to CNS

• Motor (efferent): from CNS

What are the sensory divisions?

• Somatic: from skin, muscles, joints

• Visceral: from organs (thorax/abdomen)

What are the motor divisions?

• Somatic: to skeletal muscles (voluntary)

• Autonomic (ANS): to organs (involuntary)

What are the two parts of the ANS?

• Sympathetic: "Fight or Flight"

• Parasympathetic: "Rest and Digest"

What are neuroglia (glial cells)?

Support cells for neurons

. CNS glial cells (4 types)?

• Astrocytes: blood-brain barrier

• Microglia: immune defense

• Ependymal: CSF production

• Oligodendrocytes: myelinate CNS axons

PNS glial cells (2 types)?

• Schwann cells: myelinate PNS axons

• Satellite cells: regulate around ganglia

What are the parts of a neuron?

• Cell body (soma)

• Dendrites (receive signals)

• Axon (sends signals)

• Axon hillock (start of axon)

• Axon terminals (release neurotransmitters)

What is myelin?

Insulating layer that increases signal speed

Who makes myelin?

• CNS: Oligodendrocytes

• PNS: Schwann cells

What is anterograde transport?

Moves materials from soma → axon terminal

What is retrograde transport?

Moves materials from axon terminal → soma

Multipolar

1 axon, many dendrites (motor neurons)

Bipolar:

1 axon, 1 dendrite (special senses)

Unipolar:

1 process (sensory neurons)

Types of neurons by function:

• Sensory: to CNS

• Interneurons: connect neurons

• Motor: from CNS to effectors

What is a nerve?

Bundle of axons in the PNS

Nerve structure layers:

• Endoneurium (around each fiber)

• Perineurium (around fascicles)

• Epineurium (around whole nerve)

What is resting membrane potential?

Electrical charge difference across the neuron membrane

What are ion channels?

• Leakage channels: always open

• Gated channels: open/close in response to signals