THE NERVOUS SYSTEM

Define the term Nervous system?

The Nervous system is the body’s command centre. It controls all parts of the body

The nervous system can be subdivided into how many types? List them

Three.

1. Central Nervous System

2. Peripheral Nervous System

3. Enteric Nervous System(a.k.a second brain)

   Although the ENS is thought of to be a branch of the ANS(of the peripheral nervous system) in some textbooks.

What does the central nervous system do?

It is responsible for integrating sensory information and coordinating responses

What does the peripheral nervous system do?

Acts as a communication relay, sending sensory information to the CNS and carrying motor commands from the CNS to muscles and glands in the body

The CNS is further subdivided into?

Brain and spinal cord

The PNS is made up of ?

Somatic and Autonomic nervous system

What does the somatic nervous system do?

It controls body and muscle movements. It is voluntary

What does the Autonomic nervous system do?

It is involuntary and controls the visceral organs and body functions like cardiac muscle regulation, blood vessels, glandular regulation and smooth muscles

List the divisions of the ANS

Sympathetic division

Parasympathetic division

What does the parasympathetic division of the ANS do?

Functions when the body is at rest. Also called the “rest and digest” system.

What does the Sympathetic division do?

Functions when the body is stressed. It prepares the body for emergencies or stress(

List the major divisions of the brain

1. Prosencephalon(fore brain)

2. Mesencephalon(midbrain)

3. Rhombencephalon(hindbrain)

The brain is continued as the spinal cord in the ______ by the ____ of the skull

Vertebral column

Foramen magnum

The structures of the brain and spinal cord are arranged in how many layers? State them

Grey matter

White matter

The grey matter covers the____ of the brain, while the white matter covers the ____

Outer

Inner

The grey matter covers the ____ of the spinal cord, while the white matter covers the _____

Inner

Outer

What are peripheral nerves?

These are the nerves that emerge from the CNS, creating an outside network as they branch out into all other parts of the body(I.e skin, muscles, organs and glands)

List the types of peripheral nerves

1. Cranial nerves

2. Spinal nerves

There are ____ pairs of cranial nerves in the body?

12

There are ____pairs of spinal nerves in the body?

31

Spinal nerves leave the spinal cord through?

The intervertebral foramina

There are ___ roots of the spinal nerve? List and explain their functions

Two

Dorsal or posterior root: contains sensory neurons, carries impulses toward the CNS

Ventral or anterior root: contains motor neurons, carries impulses away from the CNS

Define the term sensory ganglia?

These are clusters of sensory nerve cell bodies located outside the CNS

State the functions of the sensory ganglia

They act as critical relay stations transmitting sensory information from the body’s periphery to the CNS

List the types of sensory ganglia

Dorsal root ganglia

Central root ganglia

Where is the dorsal root ganglia located?

At the posterior root of the spinal nerve just outside the spinal cord

What does the dorsal root ganglia do in the body?

They contain the cell bodies of sensory neurons that innervate the trunk, limbs and visceral organs

The cranial nerve ganglia is associated with _____?

Specific cranial nerves

List the types of cranial nerves in chronological order, stating whether they are sensory, motor or mixed.

1. Olfactory nerve: sensory

2. Optic nerve : sensory

3. Oculomotor nerve : motor

4. Trochlear nerve : motor

5. Trigeminal nerve : both

6. Abducens nerve: motor

7. Facial nerve: both

8. Vestibulocochlear nerve: sensory

9. Glossopharyngeal nerve : both

10. Vagus nerve: both

11. Accessory nerve: motor

12. Hypoglossal nerve: motor

The neurons in sensory ganglia are typically?

Unipolar or pseudopolar

The neurons in the autonomic ganglia are typically ?

Multipolar

The support cells of a nervous system are collectively known as?

Glial cells, neuroglia or just glia

List the supporting cells of the CNS

Oligodendrocytes

Astrocytes

Microglia

Epedymal cells

List the supporting cells of the PNS

Schwann cells

Satellite cells

What are extraocular muscles?

These are the voluntary, extrinsic muscles of the eye that attach to the sclera and control movement of the globe

List the types of extraocular muscles

1. Medial rectus

2. Lateral rectus

3. Superior recurs

4. Inferior rectus

5. Superior oblique

6. Inferior oblique

The medial rectus is innervated by?

Inferior division of the oculomotor nerve(CN3)

The lateral rectus is innervated by?

Abducens nerve(CN6)

The inferior rectus is innervated by?

Same as medial rectus

The inferior oblique is innervated by?

Same as above

The superior oblique is innervated by?

Trochlear nerve(CN4)

The superior rectus is innervated by?

The superior division of the oculomotor nerve(CN3)