The document summarizes the human nervous system. It is divided into the central nervous system (CNS) and peripheral nervous system. The CNS contains the brain and spinal cord. The brain is divided into the forebrain, midbrain, and hindbrain. The spinal cord extends from the brain and transmits signals between the brain and body. The peripheral nervous system includes the somatic and autonomic nervous systems. The somatic system connects to skeletal muscles while the autonomic system regulates involuntary functions.

1. HUMAN NERVOUS SYSTEM
By:
ARTI SAHU
Supervised By:
DR. ANJANA PUROHIT
Department of Psychology

2. INTRODUCTION
• Nervous system controls all the activities of the body.
• It is divided into 2 major parts:
1. Central Nervous System and
2. Peripheral Nervous System

4. Central Nervous System (CNS)
• The part of the nervous system, which occupies the central
axis of the body, is called CNS.
• It is formed by neurons and supporting cells called neuroglia.
• It comprises:
1. The Brain
2. The Spinal Cord

6. The Brain
• Brain weighs about 1.5 kg in adults.
• It is protected by a bony covering called skull and 3
membrane coverings (meninges), namely dura mater,
arachnoid mater and pia mater.
• Cerebrospinal fluid fills the space between arachnoid and
pia, and act as a watery cusion.

8. The Brain
• It is divided into 3 parts:
1. Fore brain (Prosencephalon)
2. Mid brain (Mesencephalon)
3. Hind brain (Rhombencephalon)

10. Fore brain (Prosencephalon)
• It subdivided into 2 parts:
1. Telencephalon: It consists of two cerebral hemispheres
(or cerebrum), basal ganglia, hippocampus and
amygdaloid nucleus.
2. Diencephalon: It consists of thalamus, hypothalamus,
metathalamus and subthalamus.

11. Mid brain (Mesencephalon)
• It is divided by Aqueduct of sylvius (duct that connects
the IIIrd ventricle in the midbrain , with the IV ventricle
in the pons and medulla) into:
1. Cerebral peduncle
2. Tectum

12. Hind brain (Rhombencephalon)
• It is divided into:
1. Metencephalon, formed by pons and cerebellum
2. Myelencephalon or medulla oblongata
• Midbrain, pons and medulla oblongata are together
called the brainstem.

13. SPINAL CORD
• The spinal cord is a long (approx 45-50 cm in length),
narrow (about 2 cm in diameter) cylindrical structure.
• It lies outside the skull beginning from its base at the
foramen magnum to terminate at the lower border of 1st
lumbar vertebra.

14. SPINAL CORD
• Below the 1st lumbar vertebra the spinal cord contains the
lumbar and sacral roots in bands, known as the cauda
equina (or horse tail).
• A cross-section of the spinal cord shows anterior median
fissure, posterior median fissure and central canal.

16. SPINAL CORD
• Grey matter consisting of nerve cells forms an H-shaped
figure long and narrow dorsal horns; and thick broad
ventral horns.
• Ventral or anterior horn contains the cell bodies of α, γ
and Renshaw motor neurons; axons of α and γ motor
neurons pass out in ventral roots.

17. SPINAL CORD
• The dorsal horn receives the fibres of the posterior roots
which are purely sensory in function.
• White matter consists of descending and ascending axons
cut across.
• The sensory and motor fibres join o form a mixed nerve
which comes out from the vertebral canal as a peripheral
spinal nerve via the intervertebral foramen.

18. PERIPHERAL NERVOUS SYSTEM
• This is the part of the nervous system which lies outsude the
CNS.
• It consists of the nerves extending from the brain and Spinal
cord out to all parts of the body.
• It is divided into:
1. Somatic nervous system
2. Autonomic nervous system

19. SOMATIC NERVOUS SYSTEM
• It is made up of all the nerve fibres going from the CNS to the
skeletal muscle cells.
• It comprises:
1. Spinal nerves: 31 pairs of spinal nerves ( 8 pairs of crania N,
12 pairs of thoracic N, 5 pairs of lumbar N, 5 pairs of sacral N
and 1 pair of coccygeal N)

20. SOMATIC NERVOUS SYSTEM
2. Cranial nerves: 12 pairs of cranial nerves. They have their cell
bodies in the brain. Some are sensory, some are motor and
some are mixed nerves.

21. AUTONOMIC NERVOUS SYSTEM
• Also known as vegetative or involuntary nervous system.
• ANS innervates all tissues other than skeletal muscle.
• It is divided into:
1. Sympathetic nervous system
2. Parasympathetic nervous system

22. AUTONOMIC NERVOUS SYSTEM
• Sympathetic division consists of the thoracic and lumbar
ganglia, therefore, also called thoraco-lumbar division
• Parasympathetic division consists of the cranial ganglia (III,
VII, IX, and X cranial nerves) and sacral ganglia (2nd, 3rd and
4th sacral segments of the spinal nerves), therefore also called
craniosacral division.

24. Thank You