Central Nervous System Brain & Spinal Cord - PowerPoint Presentation

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Central Nervous System

Brain & Spinal Cord

Development of the CNS

Appears as neural tube on dorsal median plane

4

th

week brain formation begins at anterior end of the neural tube

Remaining portion of neural tube becomes spinal cord

4 Major Regions of the Brain

Cerebrum (Cerebral hemispheres)

Cerebellum

Brain Stem

Diencephalon

Cerebrum

Divided into left and right hemispheres (What do you already know about them?)

Surface is covered in elevated ridges and shallow grooves

Gyri

- ridges

Sulci

- grooves

Let’s think of a way to remember these!

Fissures are deep grooves that separate large regions of the brain

Cerebrum

Gray matter:

Outermost portion of the cerebral cortex

Neuronal cell bodies are located here

White matter:

Inner tissue of cerebrum

Bundles of fiber tracts (neuronal axons!)

Basal nuclei- small islands of gray matter within inner cerebrum

Regulate voluntary motor activities

The Brain Matters



Locate the gray matter, the white matter, and the basal nuclei.

Cerebrum separated into 4 lobes

Each lobe of the cerebrum is unique

Frontal Lobes

Parietal Lobes

Temporal Lobes

Occipital Lobe

Do these names sound familiar?

Corpus

Callosum

Large fiber tract

Connects and allows communication between left & right hemisphere

“Split-Brain” patients

Severed corpus

callosum

Split-Brain Patients

Article:

http://www.nature.com/news/the-split-brain-a-tale-of-two-halves-1.10213

Brain Stem

Parts of the Brain Stem:

Midbrain

Pons

Medulla oblongata

Provides a pathway for ascending & descending tracts from the brain to the spinal cord

Reticular Formation

Gray matter extending along brain stem involved in motor control of organs & consciousness

Brain Stem

Diencephalon

Located on top of the brainstem surrounded by the cerebral hemispheres

Many structures in the diencephalon

Thalamus

Hypothalamus

Pituitary

Pineal Body

Choroid Plexus

Amygdala

Hippocampus

Cerebellum

Located under the occipital lobe of the cerebrum

It has two hemispheres with an outer cortex of gray matter and inner region of white matter

“Let Me Pick Your Brain” Activity

Awesome 3D Brain Website

:

G2conline.com

Pages 235-241 in your book

CNS Protection

Bones of the skull and vertebral column

Connective tissue membranes called

Meninges

Aqueous cushion called the cerebrospinal fluid (CSF)

Blood-brain barrier made by the least permeable capillaries in the body keeps the brain in a constant environment

What would happen if the brain were exposed to various ions?

Meninges of the Brain

Dura Mater

Outermost thick, tough, double layered membrane

Arachnoid

Mater

Middle layer with many projections that has CSF flowing through it

Arachnoid

villi

protrude through

dura

mater, allowing CSF to drain into superior

sagittal

sinus to the blood

Pia

Mater

Delicate innermost vascular layer that follows every convolution of the brain and spinal cord

Cerebrospinal Fluid

We know where it drains… but where is it made?

Made in the choroid plexuses on roof of ventricles in the brain

The choroid plexuses make about 20-30

mL

of CSF per hour

The body has about 150

mL

of CSF at a time

Circulates throughout the CNS

Which cells help circulate CSF?

Blood-Brain Barrier

Brain is the only body organ that cannot handle any environmental fluctuations

Neurons are sequestered from substances in the blood by nearly impermeable capillaries

Spinal Cord

Continuation of the brain stem

3 layers of

Meninges

31 pairs of spinal nerves

Gray matter is on the inside & contains neuron cell bodies

White matter is on the outside & contains

axons