CENTRAL NERVOUS SYSTEM

Cranial Meninges

Dura Mater

• Periosteal Layer

• Meningeal Layer

  • Falx Cerebri, Falx Cerebelli, Tentorium cerebelli

• Subdural Space

  • potential space

Arachnoid

• subarachnoid space contains CSF, blood vessels, and fibers

Pia Mater

• connective tissue tightly clinging to brain and richly vascularized

Four Basic Brain Regions

Cerebellum

Diencephalon

• Thalamus

• Hypothalamus

Brain Stem

• midbrain

• pons

• medulla oblongata

Cerebellum

Gyri

folds in the brain

Sulcus

shallow depressions in the brain

Grey Matter

• forms brain cortex

• motor neurons, interneurons, unmyelinated axons

White Matter

• surrounded by outer cortex

• myelinated axons

internal clusters of grey matter

nuclei

choroid plexus

produces CSF

FLOW OF CSF

1. Lateral Ventricle

• Interventricular Foramina

2. Third Ventricle

• Aqueduct of the Midbrain

3. Fourth Ventricle

• Apertures (lateral and median)

4. Subarachnoid Space

5. Sinuses (dural venous)

Blood Brain Barrier: In’s and Out’s

In:

• oxygen, carbon dioxide,glucose

• alcohol

• nicotine

• anesthetics

Out:

• blood-borne toxins

• antibiotics

• proteins

• pathogens

Blood Brain Barrier: Composition

• endothelial cell junctions that line brain capillaries

  • perivascular feet of astrocytes

Astrocytes: Definition, function

• type of neuroglia

• do not conduct electrical impulses

• support and nourish neurons

CSF: composition

• similar to blood plasma: white blood cells, less protein, more sodium and chloride ions

Brain Stem: Functions

• maintains automatic functions

• provide pathway for fibers between cerebrum and spinal cord

  • origin of ten cranial nerves: all innervating the face and head

Corpora Quadrigemina: Location and Function

Found in the tectum

Superior Colliculi

• visual reflexes

Inferior Colliculi

• auditory reflexes

Red Nucleus: Location and Function

found in the tegmentum, deep to substantia nigra

• coordination of movement

  • axons from cerebrum and cerebellum for synapses here

• color from rich blood supply and iron content

Substantia Nigra: Location and Function

Brainstem: Midbrain: behind cerebral peduncles: in the white matter

• nucleus filled with melanin pigment

• control subconscious muscle activities

  • related to Parkinson’s disease

Cerebral Peduncles: Location and Function

Brainstem: Midbrain: Anterolateral surface

• connect brainstem to cerebrum

• contain corticospinal tracts

• conduct impulses from motor areas to spinal cord and rest of brain

Mesencephalic Nucleus: Location and Functions

Brainstem: Midbrain: Same level as Pons

• associated with trigeminal nerve

  • jaw-jerk reflex

  • mastication

Periaqueductal Grey Matter: Location and Function

Brainstem: Midbrain: lines cerebral aqueduct

• fight or flight reaction: increase heart rate and blood pressure

• mediates responses to visceral pain: lower heart rate and blood pressure