CENTRAL NERVOUS SYSTEM

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CENTRAL NERVOUS SYSTEM (CNS)


Central Nervous System Tumors: A Challenge for Navigators and ...This comprises of two parts i.e. Brain and Spinal Cord. The CNS is named because it integrates the received information and coordinates and influence the activity of all parts of the body.

·       SPINAL CORD
The spinal cord is a long, thin bundle of nervous tissue and support cells connected to the brain and located along your back and neck.
All the sensory information from various parts of the body are received here and then sent to higher parts of the brain.
All motor information from brain first enters spinal cord and then sent to different parts of body for action. Besides this, the spinal cord also functions as center of reflex actions.

·       BRAIN
The brain is the organ located within the skull that is responsible for cognition, mental processes, and control of the body and its functions.
Within the skull, the brain is protected by three layers of tissues called meninges.
The brain is divided into three parts, which is as given below ;

A.    Hind Brain ( Medulla, Pons, Cerebellum and Reticular Formation)
B.    Mid Brain ( Situated between Forebrain and Hindbrain )
C.    Fore Brain ( Thalamus, Hypothalamus and Cerebrum )

A.    HIND BRAIN – The first and foremost structure of Hind brain is Medulla.
·       Medulla: Medulla connects higher parts of the brain with spinal Cord.
·       Pons : It’s located above the medulla. It contains different types of sensory and motor neurons. It receives sensory information from some parts of face and head and sensations of touch, pain and temperature. It also regulates motor activities related to facial expressions, muscular activities, eye balls and Jaw movement.
·       Cerebellum : Its outer structure is composed of grey matters while inner structure is made up of white matter. It’s main function is to coordinate motor activities. Destruction of cerebellum leads to lack of coordination as for example- “ A person can walk but his pace/step would be disorganized.”
·       Reticular Formation : The reticular formation is a part of the brain that is involved in actions such as Awaking/Sleeping cycle process.

B.   MID BRAIN – It acts as a bridge between forebrain and Hind Brain . It has two subdivisions called:   (1) Tectum
                                                                     (2) Tegmentum

·       Tectum – It has a pair of structures called :-
1)    Superior Colliculi – is roof and concerned with Visual Information.
2)    Inferior Colliculi – is on the floor and deals with auditory information.

·       Tegmentum – It lies below tectum. It has some important structures, end of reticular formation an nuclei controlling the activities of eye movements.

HUMAN BEING :: ANATOMY :: NERVOUS SYSTEM :: CENTRAL NERVOUS SYSTEM ...C.    FOREBRAIN – It is the most important part of the brain. This portion of brain regulates and controls all higher and complex activities of human beings. Ex : Thinking, Reasoning and Memory.

·       It divides it into two parts :-
1.    Telencephalon – includes Cerebral Hemispheres, Limbic System and Basal Ganglia.
2.    Diencephalon – it includes Thalamus and Hypothalamus.

·       Thalamus – It receives sensory impulses relating to vision, hearing, pain, taste, and smell and sends them to appropriate parts of the cerebrum.

·       Hypothalamus – It is very important and function to regulate and control biological motives of hunger, thirst and sex. It also controls and regulates homeostatic mechanism of our body as for example: “ When we feel hot it causes us to sweat thereby reducing our body temperature and when we feel cold it causes us to shiver thereby raising our body temperature.

·       Basal Ganglia – It plays an important role in coordinating movement. Legs and Hands.

·       Limbic System – It’s a collective term referring to several brain parts.

·       The Cerebrum – Divided into 4 parts :
1.    Frontal Lobe – motor function, aggression and mood.
2.    Parental Lobe – reception and sensory information.
3.    Temporal lobe – smell, hearing, memory and thoughts.
4.    Occipital Lobe – Visual processing.



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