WRITE A DETAILED NOTE ON BRAIN WHICH IS OUR CENTRAL NERVOUS SYSTEM

✦✦✦BRAIN✦✦✦

★IN ANIMALS, ALL LIFE ACTIVITIES ARE UNDER THE CONTROL OF BRAIN.

CRANIUM;

★BRAIN IS SITUATED INSIDE A BONY CRANIUM (PART OF SKULL).

MENINGES;

★INSIDE CRANIUM, BRAIN IS COVERED BY THREE LAYERS CALLED MENINGES. 

FUNCTION OF MENINGES;

★MENINGES PROTECT BRAIN AND ALSO PROVIDE NUTRIENTS AND OXYGEN TO 

   BRAIN TISSUE THROUGH THEIR CAPILLARIES.

FLUID-FILLED VENTRICLES;

★THE BRAIN CONTAINS FLUID-FILLED VENTRICLES THAT ARE CONTINUOUS WITH

   THE CENTRAL CANAL OF SPINAL CORD.

CEREBROSPINAL FLUID;

★FLUID WITHIN VENTRICLES AND CENTRAL CANAL IS CALLED CEREBROSPINAL 

   FLUID (CSF).

DIVISIONS OF BRAIN;

THE BRAIN CAN BE DIVIDED INTO;

★FOREBRAIN

★MIDBRAIN 

★HINDBRAIN

FURTHER DIVISION OF FOREBRAIN;

 FOREBRAIN IS FURTHER DIVIDED INTO THREE FUNCTIONAL PARTS THE 

★THALAMUS,

★THE LIMBIC SYSTEM 

★THE CEREBRUM. 

THALAMUS;

★THALAMUS CARRIES SENSORY INFORMATION TO THE LIMBIC SYSTEM AND

  CEREBRUM. THE INFORMATION INCLUDES SENSORY INPUT FROM AUDITORY 

  AND VISUAL PATHWAYS, FROM THE SKIN AND FROM WITHIN THE BODY. 

LIMBIC SYSTEM;

★THE LIMBIC SYSTEM IS LOCATED IN AN ARC BETWEEN THE THALAMUS AND

   CEREBRUM. LIMBIC SYSTEM WORKS TOGETHER  TO PRODUCE OUR MOST BASIC

   AND PRIMITIVE EMOTIONS, DRIVES, AND BEHAVIOURS, INCLUDING FEAR,

   RAGE, TRANQUILLITY, HUNGER, THIRST, PLEASURE AND SEXUAL RESPONSES.

FORMATION OF MEMORIES;

★PORTION OF LIMBIC SYSTEM IS ALSO IMPORTANT IN THE FORMATION OF

   MEMORIES.

DIVISIONS OF LIMBIC SYSTEM;

★THE LIMBIC SYSTEM CONSISTS OF HYPOTHALAMUS, THE AMYGDALA, AND

    HIPPOCAMPUS, AS WELL AS NEARBY REGIONS OF CEREBRUM. 

HYPOTHALAMUS;

★THE HYPOTHALAMUS THROUGH ITS HORMONE PRODUCTION AND NEURAL

  CONNECTIONS ACTS AS A MAJOR COORDINATING CENTRE CONTROLLING BODY

  TEMPERATURE, HUNGER, THE MENSTRUAL CYCLE, WATER BALANCE, THE SLEEP-

  WAKE CYCLE ETC.

AMYGDALA;

 ★IN THE AMYGDALA, CLUSTERS OF NEURONS PRODUCE SENSATION OF PLEASURE,

   PUNISHMENT OR SEXUAL AROUSAL WHEN STIMULATED. IT IS ALSO INVOLVED IN

   THE FEELINGS OF FEAR AND RAGE.

HIPPOCAMPUS;

 ★HIPPOCAMPUS PLAYS AN IMPORTANT ROLE IN THE FORMATION OF LONG TERM 

   MEMORY, AND THUS IS REQUIRED FOR LEARNING.

CEREBRUM;

★CEREBRUM IS THE LARGEST PART OF THE BRAIN AND IS DIVIDED INTO TWO 

   HALVES, CALLED CEREBRAL HEMISPHERES. 

CORPUS CALLOSUM;

★THESE HALVES COMMUNICATE WITH EACH OTHER BY MEANS OF A LARGE

    BAND OF AXONS, CALLED CORPUS CALLOSUM. 

NO. OF NEURONS PACKED IN THIS REGION;

★TENS OF BILLIONS OF NEURONS ARE PACKED INTO THIS PART. 

CEREBRAL CORTEX;

★THE OUTER REGION, THE CEREBRAL CORTEX, FORMS FOLDS CALLED 

  CONVOLUTION WHICH GREATLY INCREASE ITS SURFACE AREA.

FUNCTION OF THIS PART;

★THIS PART RECEIVES SENSORY INFORMATION, PROCESSES IT, STORES 

  SOME IN MEMORY FOR FUTURE USE, DIRECTS VOLUNTARY MOVEMENTS

  AND IS RESPONSIBLE FOR THE POORLY UNDERSTOOD PROCESS THAT WE 

  CALL THINKING. 

CENTRE FOR SENDING IMPULSES;

★THIS AREA ALSO A CENTRE FOR SENDING IMPULSE TO VOLUNTARY MUSCLES,

   CONTROLLING MOVEMENTS. THIS IS ALSO INVOLVED IN INTELLIGENCE, 

   REASONING AND JUDGEMENT.

LEFT CEREBRAL HEMISPHERE;

★THE LEFT CEREBRAL HEMISPHERE CONTROLS THE RIGHT SIDE OF THE BODY,

RIGHT CEREBRAL HEMISPHERE;

 ★AND RIGHT CEREBRAL HEMISPHERE CONTROLS THE LEFT SIDE OF THE BODY.

MIDBRAIN;

★MIDBRAIN IS REDUCED IN HUMANS, AND IT CONTAINS AUDITORY RELAY

  CENTRE AND CENTRE THAT CONTROLS REFLEX MOVEMENTS OF EYES.

RETICULAR FORMATION;

★MIDBRAIN CONTAINS RETICULAR FORMATION, WHICH IS A RELAY CENTRE

  CONNECTING HINDBRAIN WITH THE FOREBRAIN. RETICULAR FORMATION

  IS VERY IMPORTANT IN SCREENING THE INPUT INFORMATION, BEFORE

  THEY REACH HIGHER BRAIN CENTRES. 

HINDBRAIN;

★HINDBRAIN INCLUDES THE MEDULLA, PONS AND CEREBELLUM.

MEDULLA;

★MEDULLA CONTROLS SEVERAL AUTOMATIC FUNCTIONS, SUCH AS 

  BREATHING, HEART RATE, BLOOD PRESSURE AND SWALLOWING. 

PONS;

★CERTAIN NEURONS IN PONS, LOCATED ABOVE THE MEDULLA, APPEAR

   TO INFLUENCE TRANSITIONS BETWEEN SLEEP AND WAKEFULNESS, AND

   THE RATE AND PATTERN OF BREATHING.

CEREBELLUM;

★THE CEREBELLUM IS IMPORTANT IN COORDINATING MOVEMENTS OF 

   THE BODY. 

FUNCTION OF CEREBELLUM;

★THE CEREBELLUM GUIDES, SMOOTH AND ACCURATE MOTIONS AND 

   MAINTAINS BODY POSITION. 

★THE CEREBELLUM IS ALSO INVOLVED IN THE LEARNING AND MEMORY

   STORAGE FOR BEHAVIOURS.

★IT IS BEST DEVELOPED IN BIRD, WHICH IS ENGAGED IN THE COMPLEX 

  ACTIVITY OF FLIGHT.