Nervous System Overview

Afferent

________ (sensory neurons): nerve fibers responsible for bringing sensory information from different parts of the body to the CNS.

Interneurons

________: central nodes of neural circuits, enabling communication between sensory or motor neurons and the CNS.

Spinal cord

________: gray matter surrounded by white matter.

Cell bodies

________ are located just outside of the spinal cord in the dorsal root ganglion.

White matter

________: mainly nerve fibres with their myelin sheaths.

Brain

________: white matter surrounded by grey matter.

Brain

white matter surrounded by grey matter

White matter

mainly nerve fibres with their myelin sheaths

Grey matter

mainly nerve cell bodies and branching dendrites

Spinal cord

gray matter surrounded by white matter

Parasympathetic Nervous System

discrete activation

Sympathetic Nervous System

diffuse activation

Afferent (sensory neurons)

nerve fibers responsible for bringing sensory information from different parts of the body to the CNS

Interneurons

central nodes of neural circuits, enabling communication between sensory or motor neurons and the CNS

Efferent nerves

nerves that carry nerve impulses away from the CNS

chemical transmitter

acetyl choline

either

acetyl choline or norepinephrine

Nervous System consists of

• Central Nervous System (CNS)

• Peripheral Nervous System (PNS)

the Central Nervous System (CNS) can be divided into

• Brain

• Spinal cord

the Peripheral Nervous System (PNS) can be divided into

• Somatic Nervous System

• Autonomic Nervous System

12 pairs of cranial nerves:

• olfactory (CN I)

• optic (CN II)

• oculomotor (CN III)

• trochlear (CN IV)

• trigeminal (CN V)

• abducent (or abducens; CN VI)

• facial (CN VII)

• vestibulocochlear (CN VIII)

• glossopharyngeal (CN IX)

• vagus (CN X)

• accessory (CN XI)

• hypoglossal (CN XII)

31 pairs of spinal nerves:

• 8 cervical nerve pairs (C1-C8)

• 12 thoracic nerve pairs (T1-T12)

• 5 lumbar nerve pairs (L1-L5)

• 5 sacral (S1-S5)

• 1 coccygeal nerve pair

Types of Neurons

• Afferent (sensory neurons)

• Interneurons

• Efferent nerves (motor neurons)

3 main parts of the Brain

• cerebrum

• brainstem

• cerebellum

Somatic Nervous System innervates

skeletal muscles

Autonomic Nervous System innervates

smooth muscles

one neuron between CNS and the target organ in the _____ nervous system

**Somatic Nervous System**

Autonomic Nervous System

two neurons between CNS and the target organ

Autonomic Nervous System efferent arise from

lateral horn cells

Somatic Nervous System chemical transmitter

acetylcholine

Autonomic Nervous System chemical transmitter

acetylcholine or norepinephrine