pdf human brain

The HUMAN

BRAIN

Protective Structures

Meninges Three layers of

connective tissue that

enclose the brain

Dura Mater

Arachnoid

Pia Mater

Dura Mater

Outermost layer

Thickest and

toughest part of the

meninges

There are two

layers, the outer

layer is fused to the

cranial bones.

Dura Mater In various places,

the two layers

separate to allow

venous channels

called dural sinuses

to drain blood from

the brain.

Function

containment of the

cerebrospinal fluid

in the brain.

ArachnoidMiddle layer of

the meninges

Loosley attached

to the pia mater by

weblike fibers.

Function Allows

for movement of

cerebrospinal

fluid.

Cerebrospinal Fluid

Fluid that circulates

in and around the

brain.

Protects the brain

from shock and injury.

Function-Transports

nutrients and waste to

and from cells.

.

Cerebrospinal Fluid

Formed in four spaces

called ventricals.

The ventricals hold a

vascular portion called

the choroid plexus,

which produces the

cerebrospinal fluid by

filtering the blood and

cellular excretion.

Pia Mater Innermost layer of

the meninges

A delicate connective

tissue that covers the

brain and spinal chord

Function-Holds the

blood vessels that

supply nutrients and

oxygen to the brain

and spinal cord.

Meninges

CerebralHemispheres

Structure of the Hemispheres

Two layers

An outer layer of

gray matter

called the

cerebral

cortex.

Supported by an

inner layer of

white matter

Structure of the hemispheres

Each hemisphere has four lobes

Frontal

Parietal

Temporal

Occipital

Gray Matter – The Cerebral Cortex

The most highly evolved portion of the brain.

Arranged in folds of elevations called

gyri, and grooves

called sulci


Gyri and Sulci

The surfaces on

which brain cells

reside.

More surface = more

complex calculations


White Matter

Connects the gray

matter areas with

one another and

with other parts of

the brain.

Dispersed in a tree

like pattern

Made of

myelinated fibers

White and Gray Matter

White matter

Gray Matter


Corpus Callosum

Largest white matter

structure in the brain

Facilitates communication

between the right and left

hemispheres by electrical

impulses


Basal Ganglia

Base of forbrain, deep

in each hemisphere.

Functions: helps to re-

gulate body movement

and facial expressions.


Internal Capsule

In between the hemi-

spheres and the brain

stem

Function – Carries im-

pulses between the

cerebral hemispheres

and the brainstem.

Functions of the Cerebral Cortex

The functions of the Cerebral Cortex are

localized according to the four lobes. They

are named for the

overlying cranial

bones.

CEREBRAL CORTEX FUNCTIONS

CEREBRAL CORTEX- Functions

Conscious deliberation

Voluntary actions

Memory

Association

Discrimination

Judgement


The Frontal Lobe lies

anterior to the central

sulcus.

Functions of the Cerebral

Cortex

Some Frontal Lobe Functions Contains an area that provides the conscious

control of skeletal muscles.

Contains two areas that are important in

speech


The Parietal Lobe

occupies the superior

part of each hemisphere

and lies posterior to the

central nucleus


Some Parietal Lobe Functions

Contains a primary sensory area where

impulses from the skin are interpreted

Estimates distance and size.


The Temporal Lobe lies

inferior the lateral sulcus

snd folds under the hemi-

sphere on each side.


Some Temporal Lobe Functions

Responsible for receiving and interpreting

auditory impulses from the ear.

An olfactory area that concerns the sense

of smell.


The Occipital Lobe

lies posterior to the

parietal lobe and

extends over the

cerebellum.


Some Occipital Lobe Functions

Visual receiving area and visual ass-

ociation for interpreting impulses from

the retina of the eye.


The Insula lies deep within each hemisphere

and

cannot be seen

from the surface.


The Insula Functions

Visceral reactions and judgments

Receives, integrates and responds to

autonomic influx.

Communication areas of the lobes

TEMPORAL LOBE

Auditory Cortex

Lies at the posterior

area of the temporal

lobe

Contains the auditory

receiving and

association areas.


Auditory Receiving Area

Detects sound impulses from

the surrounding environment

Auditory association area

Interprets and translates the

sound impulses.

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FRONTAL LOBE- Motor cortex

Lies anterior to the most inferior part of the

frontal lobe

Contains the Broca area


Broca Area – Responsible for spoken and

written communication.

Functions- Controls:

Muscles in the tongue

Soft Palate

The larynyx

Lies anterior to the area that controls the arm

and hand muscles that produce written speech

DiencephalonThe area between

the cerebral

hemispheres

and the brain stem.

Contains the

thalamus

and the

hypothalamus.

The Thalamus

Sorts and directs sensory

impulses to areas of the

cerebral cortex.

Nearly all sensory

impulses travel through

the thalamus.

Important role in sleep

and

wakefullness.

Hypothalamus

Located inferior to the

thalamus

The Boss of you.

Hypothalamus

Helps maintain

homeostasis

Controls autonomic

function such as:

heartbeat, blood flow,

and hormone secretion.

Controls the pituitary

gland.

Pituitary Gland

A „master gland‟ lo-

cated at the bottom

of the hypothalamus.

Pea sized

Assists in the regulation

of homeostasis.

Pituitary Gland

Functions Helps to regulate:

Growth

Blood pressure

Child birth

Sex organ function

Thyroid gland

Metabolism

Temperature regulation

Hypothalamus/ Pituitary

Homeostasis

Balance

Maintenance

of body con-

ditions within

set limits.

The Limbic System

Located between the

cerebrum and diencephalon

Includes the Hip-

pocampus

Links conscious functions

of the cerebral cortex and

autonomic functions of the

brainstem.

The Limbic System

Emotional states and

behavior

Formation of long

term memory

The Hippocampus

Long term

memory

Spacial

navigation

The Hippocampus

The Brain Stem

The brainstem

is located in the

anterior region

below the cerebrum

The Brain Stem

Connects the cerebrum and the

diencephalon with the spinal cord.

The brainstem includes:

The Midbrain

The Pons

The Medulla Oblongata

The Midbrain

The midbrain is located below the center of the

cerebrum.

The midbrain forms the superior part of the brain

stem.

The Midbrain

The midbrain consists of centers that are

concerned with aspects of vision and

hearing.

The Pons

Located anterior to the cerebellum.

Lies between the midbrain and the medulla

Connects the two halves of the cerebellum

with the brainstem.

Medulla Oblongata

Located between the pons and

spinal cord.

Contains gray matter which

has centers that play an

important role in many

involuntary actions such as

respiration.

The centers are called vital

centers.

The Medulla Vital Centers

The respiratory center

The cardiac center

The vasomotor center

The Cerebellum “Little Brain”

Divided into two hemispheres,

and one middle part(vermis).

Outer layer gray matter, inner

layer white matter.

Located above the brainstem,

and beneath the occipital

lobes.

The Cerebellum

Functions:

Coordination in voluntary

movement.

Helps maintain balance

and equilibrium.

Helps maintain muscle

tone.

Brain Studies

Imaging used to study the brain

without physically entering it

CT Scan Provides photographs of the bone,

soft tissue, and cavities of the brain. Used to de-

tect:

Scar tissue accumulations

Anatomic lesions such as tumors

Brain Studies

MRI Magnetic Resonance Imaging

Shows more views than CT scans

Often reveals issues that the CT

scan can miss such as tumors, scar

tissue, and hemorrhaging.

Brain Studies

The Electroencephalograph records

Electrical currents produced by the brain‟s

Nerve cells.

Brain Studies EEG

Cranial Nerves

Cranial Nerves

12 pairs of cranial nerves

Numbered 1- 12 based on

connection with the brain.

Originate in the brain stem

Divided into 4 categories

based on the impulses they

send.

Cranial Nerves Types

Special sensory impulses

Located in special sense

organs in the head, responsible

for:

Smell

Taste

Vision

Hearing


General sensory impulses

Originate from receptors through the body.

Pain

Touch

Temp

Pressure

Vibration

Deep muscle sense


Somatic Motor Impulses

Voluntary control of skeletal muscles


VISCERAL MOTOR IMPULSES

Part of autonomic nervous system

Involuntary control of glands

and involuntary muscle

Aging and the Nervous System

Aging of the brain

The brain loses 5-10 % of it’s

volume between

the ages of 20-90.

The grooves widen and the

surface shrinks.

Aging in the brain

Senile plaque forms

Synapses and neurons

decrease, esp in the cere-

bral cortex.

Aging of

the Brain

Aging in the brain

Movement is slowed

Information processing slows

Chance of stroke, and alzheimers increases

Dementia

Loss of cognitive ability in a previously-unimpaired

person, beyond what might be expected from

normal aging.

Massage - Yes

Alzheimers

Alzheimer’s

disease leads to

nerve cell death

and tissue loss

throughout the

brain. Over time,

the brain shrinks

dramatically,

affecting nearly all

its functions.

Massage –Yes, best to

start in early stages

Multiple Sclerosis

Eats away at the protective

sheath that covers your

nerves. This interferes with

the communication between

your brain and the rest of

your body.

Massage- During

remissions

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