NERVOUS SYSTEM and it's division

a brief description on division of nervous system,SOMATIC NERVOUS SYSTEM and working, SENSORY DIVISION and MOTOR DIVISION, SENSORY RECEPTORS, CATEGORIZATION OF SENSORY RECEPTORS, TYPES OF NERVES, SPINAL NERVES, CRANIAL NERVES, REFLEX ARCS, AUTONOMIC NERVOUS SYSTEM and it's properties and division, PARASYMPATHETIC NERVOUS SYSTEM, SYMPATHETIC NERVOUS SYSTEM

1. NERVOUS SYSTEM Function of somatic and autonomic nervous system

2. NERVOUS SYSTEM DEFINITION ‘ The network of nerve cell and fiber which transmit nerve impulses b/w parts of body. ’

3. DIVISION OF NERVOUS SYSTEM

4. SOMATIC NERVOUS SYSTEM VOLUNTARY NERVOUS SYSTEM . DEFINITION “ part of peripheral nervous system associated with the voluntary control of body movement via skeletal muscles .”

5. WORKING When stimulated, sensory receptors send impulses to sensory neurons. Sensory neurons then send impulses to the central nervous system . For example, walking by flowers will stimulate chemoreceptors and photoreceptors .

6. SENSORY DIVISION SNS consists of   somatic nervous system consists  of afferent  nerves  or sensory  nerves , and efferent  nerves  or motor  nerves . The  somatic nervous system  controls all voluntary muscular  systems within the body, and also mediates involuntary reflex arcs.

7. SENSORY RECEPTORS SENSORY RECEPTORS are cells that send info. a bout changes in external as well as internal environment These changes are called STIMULI

8. CATEGORIZATION OF SENSORY RECEPTORS

9. TYPES OF NERVES

10. SPINAL NERVES 31 pairs and 62 spinal nerves. Each spinal nerve has a VENTRAL ROOT and a DORSAL ROOT. VENTRAL ROOT : has motor fibers , efferent fibers transmit message from CNS to effectors cell body found in the spinal cord gray matter DORSOL ROOT : sensory fibers , afferent fibers carry information from sensory receptor to CNS

11. CRANIAL NERVES 12 pairs of cranial nerves and 24 total cranial nerves Transmit information on the senses of sight , smell , balance , taste and hearing from the special sensory receptors Also transmit information from general sensory receptors in the body , largely from the head . Information is received and processed by the CNS and then the response travels via the cranial nerves to the skeletal muscle to control movements in face and throat e.g. smiling and swallowing .

12. REFLEX ARCS Although the somatic nervous system is generally considered to be under conscious control, some actions of the system occur automatically. For example, if you accidentally step on a tack with your bare foot, your leg may recoil before you are even aware of the pain . This rapid response (a reflex) is caused by impulses that travel a pathway known as a reflex arc.

13. REFLEX ARCS 1 2 3 4 5

14. AUTONOMIC NERVOUS SYSTEM The autonomic nervous system regulates activities that are involuntary, or not under conscious control. The autonomic nervous system consists of two parts, the sympathetic nervous system and the parasympathetic nervous system. In general, the sympathetic and parasympathetic systems have opposite effects on each organ . Consists of only motor nerves. Within the brain, the autonomic nervous system is regulated by the hypothalamus. Autonomic functions include control of respiration ,  cardiac regulation (the cardiac control center), vasomotor activity (the vasomotor center), and certain reflex actions such as coughing, sneezing, swallowing and  vomiting .

15. Sometimes called the rest and digest  system . The parasympathetic system  conserves energy as it slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract . The parasympathetic nervous system consists of cells with bodies in one of two locations: the brainstem (Cranial Nerves III, VII, IX, X) or the sacral spinal cord (S2, S3, S4). These are the preganglionic neurons , which synapse with postganglionic neurons

16. REST RELAX RUMINATE

17.  The  sympathetic nervous system  activates what is often termed the fight or flight response . the  sympathetic nervous system  can accelerate heart rate, widen bronchial passages, decrease motility of the large intestine, constrict blood vessels, increase peristalsis in the esophagus, cause pupillary dilation, piloerection (goose bumps) and perspiration (sweating), and raise blood pressure Sympathetic neurons are frequently considered part of the peripheral nervous system (PNS), although there are many that lie within the central nervous system (CNS ). Sympathetic nerves originate inside the vertebral column, toward the middle of the spinal cord in the intermediolateral cell column (or lateral horn), beginning at the first thoracic segment of the spinal cord and are thought to extend to the second or third lumbar segments.