2 Anatomy of the Nervous System

Neuroanatomy

The anatomy of the nervous system, studying its various parts and functions.

Dorsal

Toward the back, away from the ventral (stomach) side.

Ventral

Toward the stomach, away from the dorsal (back) side.

Anterior

Toward the front end.

Posterior

Toward the rear end.

Superior

Above another part.

Inferior

Below another part.

Lateral

Toward the side, away from the midline.

Medial

Toward the midline, away from the side.

Proximal

Located close to the point of origin or attachment.

Distal

Located more distant from the point of origin or attachment.

Ipsilateral

On the same side of the body.

Contralateral

On the opposite side of the body.

Coronal plane

A plane that shows brain structures as seen from the front.

Sagittal plane

A plane that shows brain structures as seen from the side.

Horizontal plane

A plane that shows brain structures as seen from above.

Meninges

Three protective membranes inside the skull.

Dura Mater means

Hard Mother

Dura Mater

Tough and outermost layer of protection inside the skull.

Arachnoid Space

network of connective tissue and is avascular

Subarachnoid space

contains many large blood vessels and cerebrospinal fluid. It exists between the arachnoid space externally and pia mater internally.

Pia mater means

Pious Mother

Pia Mater

the delicate and innermost meninx which adheres to the surface of the CNS.

Cerebrospinal Fluid (CSF)

Supports and cushions the brain. It fills the subarachnoid space and central canal of the spinal cord.

Choroid Plexus

A network of capillaries that produces CSF.

Central canal

a small central channel that runs the length of the spinal cord

Cerebral Ventricles

Pathways for CSF flow

The four large internal chambers of the brain:

the two lateral ventricles, the third ventricle, and the fourth ventricle.

Cerebral Aqueduct / Aqueduct of Sylvius

Connects Third Ventricle and Diencephelon and the Fourth Ventricle

Hydrocephalus

A condition characterized by an accumulation of CSF in the brain.

Flow of CSF

1. CSF secreted by choroid plexus in lateral ventricles.

2. CSF Flows through interventricular foramina into the third ventricle.

3. Additional CSF added in the third ventricle.

4. Flows down the cerebral aqueduct to the fourth ventricle.

5. Choroid plexus of 4th ventricle adds more CSF.

6. CSF Flowsout the two lateral apertures and one median aperture.

7. Flows out into the subarachnoid space.

8. Reabsorbed into venous blood of the dural venous sinuses at arachnoid villi.

Circle of Willis

A circular structure that supplies blood to the brain and surrounding areas.

Thomas Willis

Circle of Willis is named after

Interpeduncular Fossa

The circle of Willis is located near the ___________ at the base of the Brain

ischemia

loss of blood or oxygen thus resulting in death of tissue

Blood-Brain Barrier

A barrier that inhibits the passage of harmful substances into the brain.

Triangle of Death

it's one place where you should never pop a pimple, as it can lead to an infection in your brain.

Neurons

Specialized cells for reception, conduction, and transmission of electrochemical signals.

nuclei

In the CNS, clusters of cell bodies are called

ganglia

In the PNS, clusters of cell bodies are called

tracts

In the CNS, bundles of axons are called

nerves

In the PNS, bundles of axons are called

Glial Cells

Support and insulate neurons.

Oligodendrocytes

Cells with extensions that wrap around axons thus myelinating them.

Schwann Cells

it can guide axonal regeneration and is found in the PNS. It only constitutes one myelin segment

Microglia

They respond to injury or disease by multiplying, engulfing cellular debris or even entire cells which then triggers inflammatory responses.

Astrocytes

largest glial cells. Plays a role in the passage of some chemicals from blood into the CNS, structures neurons, modulate neural activity, maintain function of axons, and participate in glial circuit

Multipolar Neurons

The most common type of neuron, characterized by multiple extensions.

Unipolar

A neuron with one process extending from its cell body

Bipolar

A neuron with two processes extending from its cell body

Interneurons

A neuron with a short axon or no axon at all

Motor Neurons

Neurons that send signals to skeletal muscles.

Sensory Neurons

Neurons that carry information from the body to the CNS.

Grey Matter

Unmyelinated neuronal cell bodies and dendrites.

Peripheral neurons

neurons that are more susceptible to injury.

White Matter

Myelinated axons that carry information.

Spinal Cord

The part of the CNS found within the spinal column.

Gray matter and white matter

two parts of the spinal cord

dorsal horns

The two dorsal arms of the spinal gray matter are called

ventral horns

The two ventral arms of the spinal gray matter are called

Dorsal Root

Carries sensory information to the spinal cord.

Ventral Root

Carries motor information away from the spinal cord.

Bell-Magendie Law

States that entering dorsal roots carry sensory information and exiting ventral roots carry motor information.

Sympathetic Nervous System

Responsible for the "fight or flight" response.

Parasympathetic Nervous System

Responsible for "rest and digest" functions.

Sympathetic nerves

efferent nerves from the CNS in the lumbar (small of the back) and thoracic (chest area) regions of the spinal cord.

Parasympathetic nerves

efferent nerves from the Cranium (Cranial nerves) and sacral (lower back) region of the spinal cord

Cranial Nerves

Nerves that emerge directly from the brain, including sensory and motor functions.

Vagus

Longest cranial nerves which contain motor and sensory fibers traveling to and from the gut.

frontal, parietal, occipital, and temporal lobes.

Lobes of the Brain

1. Scalp

2. Periosteum

3. Skull

4. Dura mater

5. Arachnoid space

6. Pia mater

7. Brain

Layers of Protection

Foramen magnum

the opening in the base of the skull that connects the spinal cord to the brain.

Myelin

a fatty insulating substance which increases the speed and efficiency of axonal conduction

1. Cervical - 8 (C1-C8)

2. Thoracic - 12 (T1-T12)

3. Lumbar - 5 (L1-L5)

4. Sacral - 5 (S1-S5)

5. Coccygeal

31 Spinal Nerves

4 Basic Functions of the Central Nervous System

Homeostasis, Voluntary Movement, Perception, and Abstraction