organization of the nervous system (neuro ana lec)

Meninges

What is the covering of the CNS called

• Dura mater

• Arachnoid mater

• Pia mater

Meninges can be divided into 3, what are those?

Dura mater

The outer covering of meninges

Arachnoid mater

Meninges that are inside the duramater

Pia mater

Meninges within the lining of the spinal cord

Brain

Lies within the cranial cavity

Foramen magnum

A hole under the brain wherein the spinal cord begins

Cerebrospinal fluid (CSF)

The brain and spinal cord is suspended in what?

Subarachnoid space

a space inside the skull and vertebral column; the csf flows in here

• Hindbrain

• Midbrain

• Forebrain

3 divisions of the brain

• Pons

• Medulla oblongata

• Cerebellum

Parts of the hindbrain

Medulla oblongata

• Conical in shape

• superiorly to the pons

• connects pons and spinal cord

• Contains nuclei (collection of neurons)

• Conduit for ascending and descending nerve fibers

Inferiorly

Medulla oblongata is (what direction) to the spinal cord

Brainstem

Collective term for:

• medulla oblongata

• Pons

• Midbrain

Parasympathetic

Conserving and restoring energy

Sympathetic

“Emergency”

Pons

• Situated anteriorly of the cerebellum

• Inferiorly to the membrane

• Superiorly to the Medulla Oblongata

Pons

• Anterior to cerebellum

• Between midbrain and medulla oblongata

• Bridge

• transverse fibers connecting with cerebellar atmospheres

• Also helps send signals

Cerebellum

• within the posterior cranial fossa

• Posterior to pons and medulla oblongata

• 2 hemispheres connected by vermis (median portion)

Midbrain

Superior cerebellar peduncles connects to what

Pons

Middle cerebellar peduncles connects to what

Medulla

Inferior cerebellar peduncles connects to what

Fourth ventricle

A cavity that surrounds the pons, medulla, and cerebellum. This is also where the CSF pass through

Third ventricle

Usually located in the area of the forebrain which is in the diancephalon

Cerebral aqueduct

A narrow cavity located in the midbrain

Cerebellar cortex

• has surface layer consisting of gray matter

• Has folds or folia

• Separated by transverse fissures

• Has dentate nucleus

Dentate nucleus

Largest mass of gray matter found in the interior of cerebellum and embedded in white matter

Gray matter

The outer layer of the brain

White matter

Inside layer of the brain

Midbrain

• connects forebrain and hindbrain

• Has cerebral aqueduct

• Contains nuclei and ascending/descending nerve fibers

Forebrain

Contains the cerebrum and diencephalon

Diencephalon

• seen only on sagittal cuts

• Consist of thalamus and hypothalamus

Thalamus

Dorsal, large egg-shaped mass of gray matter on either side of the third ventricle

Hypothalamus

Ventral, forms the lower part of the lateral wall and floor of third venrticle

Cerebrum

• largest part of the brain

• 2 cerebral hemispheres connected by corpus callosum (mass of white matter); Separated by longitudinal fissures (deep cleft)

Cerebral cortex

Surface of hemisphere composed of gray matter

Gyri

Folds

Sulci

Fissures that separate the gyri

Lobes

Subdivisions of hemisphere, named from cranial bones

Corpus callosum

Connects the two cerebral hemispheres

Longitudinal fissure

The one that separates the two cerebral hemispheres

Basal ganglia

Masses of gray matter within the hemisphere

Lateral ventricle

Cavity within the hemisphere, communicates with third ventricle through interventricular foramina

Coronal radiata and internal capsule

Which is not a part of basal ganglia?

Internal capsule

Converges from the corona radiata to pass between the basal ganglia

• caudate nucleus

• Lentiform nucleus

The two important nuclei of the basal ganglia are?

1. Olfactory (S)

2. Optic (S)

3. Oculomotor (M)

4. Trochlear (M)

5. Trigeminal (B)

6. Abducens (M)

7. Facial (B)

8. Vestibulocochlear (S)

9. Glossopharyngeal (B)

10. Vagus (B)

11. Accessory (M)

12. Hypoglossal (M)

What are the 12 pairs of cranial nerves

Olfactory (S)

Sense of smell

Optic (S)

sense of vision

Oculomotor (M)

Motor nerve that is responsible for eye movement

Trochlear (M)

Specific to controlling the superior oblique muscle of the eye; only innervate 1 muscle

Trigeminal (B)

For the face; sensory function of the face; motor function will be for chewing, mastication

Abducens (M)

Innervate the lateral rectus muscle of the eye

Facial (B)

Its sensory function is to provide taste sensation for the anterior 2/3 of the tongue; saliva production. It’s motor function is to innervate the facial muscles

Vestibulocochlear (S)

For hearing and balance

Glossopharyngeal (B)

Innervates the posterior 1/3 of the tongue for sensation; innervates muscle involve for swallowing

Accessory (M)

Responsible for innervating the muscles of the neck and shoulder

Hypoglossal (M)

For the tongue

Posterior root ganglion

Cell bodies of afferent nerve fibers

1. Small posterior ramus

2. Large posterior ramus

Spinal nerves are divided into:

Small posterior ramus

Innervates the muscles and skins of the back (smaller area)

Large anterior ramus

Muscles and skin of anterolateral body and 4 limbs; form nerve plexuses at the root of the limbs

1. Cervical plexus

2. Brachial plexus

3. Lumbar plexus

4. Sacral plexus

Nerve plexuses that originates from the large anterior ramus

Posterior root ganglia

Where can you find the sensory ganglia

Posterior root ganglia

Fusiform swellings on post root of spinal nerve (light touch, pain temp)

Cranial nerves 5, 7, 8, 9, & 10

Which cranial nerves can the sensory ganglia be found?

Autonomic ganglia

Irregular shape along the course of efferent nerve fibers of ANS

Paravertebral sympathetic chains

Visceral arteries or visceral walls

Ectoderm

CNS comes from this

3rd week of gestation

When does the neural plate form?

Neural groove

Neural plate will eventually become what?

Neural folds

Neural grooves is bounded by what?

Neural tube

Neural folds will eventually close and become what?

After 28 days

After how many days of gestation will the neural tube close?

Neural crest

Strip of ectodermal cells between neural tube and covering

• post root ganglia

• Sensory ganglia of cranial nerves

• Autonomic ganglia

• Cells of suprarenal medulla

• Melanocytes

The following are the ones that get to be formed at the neural crest

1. Forebrain

2. Midbrain

3. Hindbrain

3 primary brain vesicles

Prosencephalon (forebrain)

Primary division of forebrain vesicle

• telencephalon

• Diencephalon

The forebrain vesicle further subdivides into:

• Cerebral hemisphere

• basal ganglia

• Hippocampus

Adult structures of telencephalon

• thalamus

• Hypothalamus

• Pineal body

• Infundibulum

Adult structures of diencephalon

Mesencephalon (midbrain)

Primary division of midbrain vesicle

Mesencephalon (midbrain)

Subdivision of midbrain vesicle

• tectum

• Tegmentum

• Crus cerebri

Adult structures of mesencephalon

Rhombencephalon (hindbrain)

Primary division of hindbrain vesicle

• metencephalon

• Myelencephalon

Subdivision of hindbrain vesicle

• pons

• Cerebellum

• Medulla oblongata

Adult structures of hindbrain vesicle