10 Brain Five Seneses

7/29/2019 10 Brain Five Seneses

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THE BRAIN & FIVE SENSES

By, Dr. Shamanthakamani

Narendran, M.D.


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THE BRAIN

The adult human brain weighs an average of 1.4kg, or about 2 percent of the total body weight.

Despite this relatively small mass, the braincontains approximately 100 billion neurons.

Functioning as a unit, these neurons make up themost complex and highly organized structure on

Earth.


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THE BRAIN

The brain is responsible for many of the qualities

that make each individual unique-thoughts,

feelings, emotions, talents, memories, and the

ability to process information.

Much of the brain is dedicated to running the

body, the brain is responsible for maintaining

Homeostasis by controlling and integrating the

various systems that make up the body.


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1. The brain is the main switching unit of the

central nervous system; It is the place to which

impulses flow and from which impulsesoriginate.

2. The spinal cord provides the link between the

brain and the rest of the body.3. The brain has three main parts:

1. The cerebrum

2. The cerebellum3. The brain stem


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The Brain is a highly organized ORGAN that

contains approximately 100 billion neurons and

has a MASS of 1.4 Kilograms.

The Brain is Protected by a BONY Coveringcalled the SKULL.

The Brain is also WRAPPED inTHREE LAYERS of

CONNECTIVE TISSUE

known as the MENINGES.


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Connective Tissue connects one tissue to another.

The INNER most layer, which covers and is boundto the surface of the brain, is called PIA MATER.

It is a FIBEROUS LAYER made up of many

Blood Vessels which carry FOOD and OXYGENto the Brain.

The OUTER Layer, called the DURA MATER, iscomposed of Thick Connective Tissue.


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The ARACHNOID is the THIN, elastic, weblike

layer between the PIA MATER and the DURA

MATER. Between the Pia Mater and theArachnoid is a space filled with

CEREBROSPINAL FLUID.


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Cerebrospinal Fluid separates the middle and inner

Meninges and fills four interconnected

VENTRICLES, or Cavities in the Brain. Within

the Ventricles, Cerebrospinal Fluid acts as a

Transport Medium for substances that areimportant to Brain Function.


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The Cerebrospinal Fluid is a clear liquid that

PROTECTS the Brain from mechanical injury byacting as a Shock Absorber.

In order for the Brain to perform its functions, it

must have a constant supply of Food and Oxygen.

If the Oxygen supply to the brain is cut off even

for a few minutes, the brain will usually suffer

enormous damage. Such damage may result in

DEATH.


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PARTS OF THE BRAINTHE CEREBRUM


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THE CEREBRUM IS THE CONTROL CENTER

OF THE BRAIN.

The LARGEST and most PROMINENT part of

the Human Brain is the CEREBRUM. 85% OF

THE WEIGHT OF A HUMAN BRAIN.

The Cerebrum is responsible for all the

VOLUNTARY (CONSCIOUS) ACTIVITIES

OF THE BODY. It is the site of INTELLIGENCE,

LEARNING AND JUDGMENT.


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IT FUNCTIONS IN LANGUAGE, CONSCIOUS

THOUGHT, MEMORY, PERSONALITYDEVELOPMENT, VISION, AND OTHER

SENSATIONS.

The Cerebrum takes up most of the space in the

cavity that houses the Brain. (SKULL)

The CEREBRUM IS DIVIDED INTO TWO

HEMISPHERES, THE LEFT AND RIGHT

CEREBRAL HEMISPHERES.


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hemispheres are linked by a bundle of neurons

called A TRACT tells each half of the brain what

the other half is doing.

There is a DEEP GROVE that

separates the Two Hemispheres.

The Hemispheres are Connected

in a region known as theCORPUS CALLOSUM.

The right and left cerebral


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The MOST Obvious FEATURE on the surface of

each hemisphere are NUMEROUS FOLDS.

These FOLDS and the GROOVES INCREASEthe Surface Area of the Cerebrum. The Ridges are

called GYRI, and the grooves are called

SULCUS.

The Cerebrum, which looks like a wrinkled

mushroom, is positioned over the rest of the brain.


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It contains thick layers of Unmyelinated Neurons,

which look GRAY. ("GRAY MATTER")

The increased

surface area

permits the largenumber of neurons

to fit easily within

the confines of theSkull.


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Each Hemisphere of the Cerebrum is divided into

Four regions called LOBES.

These LOBES are named for the SKULL BONES

that cover them, FRONTAL, PARIETAL,

TEMPORAL, AND OCCIPITAL LOBES.


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The RIGHT hemisphere is associated with

creativity and artistic ability. The LEFT

hemisphere is associated with analytical and

mathematical ability.


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Sometimes blood vessels in the brain are blocked

by blood clots, causing a disorder called A

STROKE. During a Stroke, circulation to an area

in the brain is blocked and the brain tissue dies. A

severe Stroke in one side of the brain may causePARALYSIS of the other side of the body.


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The Cerebrum consists of TWO SURFACES

The FOLDED OUTER SURFACE is called theCEREBRAL CORTEX and consists of GRAY

MATTER (UNMYELINATED NEURONS).

The INNER SURFACE is called the

CEREBRAL MEDULLA, which is made up of

bundles of MYELINATED AXONS. THE

WHITE MATTER.

The Myelin gives the White Matter its White

THE CEREBELLUM


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THE CEREBELLUM

The

CEREBELLUM is

the SECOND

LARGEST part of

the Brain, and islocated at the back

of the Skull. It

coordinatesmuscle

movements.


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The Cerebellum coordinates and balances the

actions of Muscles so that the body can move

gracefully and efficiently.

The Cerebellum CONTROLS BALANCE,

POSTURE, and COORDINATION.

The Cerebellum receives sensory impulses from

muscles, tendons, joints, eyes, and ears, as well as

input from other brain centers.


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It processes information about position and

controls posture by keeping skeletal muscles in a

constant state of partial contraction.

The Cerebellum Coordinates rapid and ongoing

movements.

This is a small CAULIFLOWER SHAPED

Structure.


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A Major part of learning how to perform physical

activities seems to be related to training the

Cerebellum to coordinate the proper muscles.

Because the function of the Cerebellum is

INVOLUNTARY (not under conscious control),learning a completely new physical activity can be

very difficult.

THE BRAIN STEM


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THE BRAIN STEM

The BRAIN STEM CONNECTS the BRAIN to

the SPINAL CORD.


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The brain stem, which maintains life support

systems, consist of the diencephalon, medulla

oblongata, pons, and the midbrain.

The Brain Stem Controls Vital Body Processes.

The Brain stem not only coordinates and integratesall INCOMING INFORMATION; it also serves as

the place of entry or exit for ten of the Twelve

Cranial Nerves.


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The Upper Brain Stem, the Diencephalon, contains

important relay centers for information entering an

exiting the brain.

The Lower Brain Stem consists of the

MEDULLA OBLONGATA, PONS, AND

MIDBRAIN.

The Lowest Part of the Brain Stem is the Medulla

Oblongata (Sometimes just called the Medulla).


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The Medulla contains WHITE MATER that

conducts impulses between the Spinal Cord and

Brain.

The MEDULLA controls involuntary functions

that include, breathing, blood pressure, heart rate,digestion, swallowing, and coughing.

Another important part of the Medulla is aGROUP of CELLS known as THE RETICULAR

ACTIVATING SYSTEM or RETICULAR

FORMATION (RAS).


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The Reticular Activation System (RAS) actually

helps to alert, or awaken, the upper parts of theBrain, including the Cerebral Cortex. Such actions

keep the Brain alert and conscious.

The RAS also helps to control respiration and

circulation and serves as a filtering system for

incoming sensory signals. For example, weawaken to the sound of an alarm clock, to a bright

light flash, or to a painful pinch because activity in

the RAS that arouses the Cerebral Cortex.


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Just above the Medulla, the brainstem enlarges to

form the PONS. PONS mean BRIDGE, and this

area of the brain stem contains mostly white matter

that provides a link between the cerebral cortex

and the cerebellum. Above the PONS andcontinuous with it is the MIDBRAIN, the smallest

division of the lower brain stem.

DIENCEPHALON


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DIENCEPHALON

THE THALAMUS AND HYPOTHALAMUS

The Thalamus and Hypothalamus are found in

the part of the brain between the Brain Stem and

Cerebrum.

The Thalamus, which is composed of Gray

Matter, serves as a SWITCHING STATIONFOR SENSORY INPUT. With the Exception of

SMELL, each Sense Channels its Sensory Nerves

through the Thalamus.


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The Thalamus passes information to the proper

region of the Cerebrum for further processing.

Immediately Below the Thalamus is the

Hypothalamus, which is the CONTROLCENTER for hunger, thirst, fatigue, anger, and

body temperature.

Parts of the Diencephalon and the Cerebrum are

included in an important group of connected Brain

Centers called the LIMBIC SYSTEM.


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The Limbic System includes the Thalamus, the

Hypothalamus, some deeper parts of the Cerebral

Cortex, and centers in the Temporal Lobes.

The Limbic system plays an important role in

emotions, memory, and motivation, among other

things.

BRAIN GROWTH IN FETUS


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BRAIN GROWTH IN FETUS

SENSORY SYSTEMS


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SENSORY SYSTEMS

Human experience is effected by both internal and

external stimuli.

Humans are able to distinguish among many

different types of stimuli by means of a highly

developed system of SENSE ORGANS.

Sensory Systems represent an integration of the

functions of the Peripheral Nervous System and

the Central Nervous System.


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The Sensory Division of the Peripheral Nervous

System gathers information about the Body's

Internal Conditions and External Environment.

Sensory Systems translate light, sound,

temperature, and other aspects of the Environment

to Electrical Signals and transmit these signals, in

the form of Action Potentials, to the CentralNervous System, where they are Interpreted.

10 Brain Five Seneses

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