parasympathetic unit IV.pptx

The Autonomic nervous system divided into two parts i.e sympathetic nervous system and parasympathetic nervous system.
ANS also consists cranial nerve and spinal nerve.

1. PERIPHERAL NERVOUS SYSTEM archita srivastava department of pharmacology

2. INTRODUCTION The peripheral nervous system (PNS) consists of all the nerves branching out of the  brain  and  spinal cord . These allow electrical impulses to travel to and from the furthest regions, or periphery, of the human body. The PNS is built almost entirely from nerves. There are two main types;  spinal nerves  and  cranial nerves .

3. Tissues of the Peripheral Nervous System The tissues that make up the PNS are nerves and ganglia . Ganglia are nervous tissues that act as relay points for messages transmitted through nerves of the PNS . Nerves are cable-like bundles of axons that make up the majority of PNS tissues. Nerves are generally classified on the basis of the direction in which they carry  nerve  impulses as sensory, motor, or mixed nerves .

4. Sensory nerves  transmit information from sensory receptors in the body to the CNS. Sensory nerves are also called afferent nerves. Motor nerves  transmit information from the CNS to muscles, organs, and glands. Motor nerves are also called efferent nerves. Mixed nerves  contain both sensory and motor neurons, so they can transmit information in both directions. They have both afferent and efferent functions.

5. Divisions of the Peripheral Nervous System The PNS is divided into two major systems autonomic nervous system somatic nervous system Both systems of the PNS interact with the CNS and include sensory and motor neurons, but they use different circuits of nerves and ganglia.

6. A utonomic nervous system The  autonomic nervous system primarily senses the internal environment and controls involuntary activities. It is responsible for monitoring conditions in the internal environment and bringing about appropriate changes in them. In general, the autonomic nervous system  is responsible for all the activities that go on inside your body without your conscious awareness or voluntary participation. Structurally, the  autonomic nervous system consists of sensory and motor nerves that run between the CNS (especially the  hypothalamus in the  brain ) and internal organs (such as the  heart , lungs, and digestive organs) and glands (such as the  pancreas and  sweat glands).

7. Sensory neurons in the autonomic system detect internal body conditions and send messages to the  brain . Motor nerves in the autonomic system function by controlling the contractions of smooth or  cardiac muscle  or glandular  tissue . For example, when sensory nerves of the autonomic system detect a rise in body temperature, motor nerves signal smooth muscles in  blood vessels near the body surface to undergo  vasodilation , and the  sweat glands in the  skin  secrete more  sweat  to cool the body. The   autonomic nervous system , in turn, has two subdivisions: the  sympathetic division and  parasympathetic division . each division have two efferent neurones b/w the CNS and Organ The preganglionic neurons The postganglionic neurons

8. preganglionic neurons & postganglionic neurons its cell body is in the brain or spinal cord its axon exits the CNS as part of spinal and cranial nerve. the axon of a preganglionic neuron is a small diameter, mylinated and synapses with postganglionic neurons. the PGN convey nerve impulse from CNS to AG the postganglionic neuron lies entirely outside the CNS. its cell body and dendrites are located in an autonomic ganglia (AG). the axon of a postganglionic neuron is a small diameter, unmylinated that terminates in the visceral effector . POGN relay the impulse from AG to visceral effector .

9. S ympathetic division C ontrols the fight-or-flight response. Changes occur in organs and glands throughout the body that prepare the body to fight or fly in response to a perceived danger . For example, the  heart rate speeds up, air passages in the lungs become wider, more  blood  flows to the skeletal muscles, and the digestive system temporarily shuts down. T horacolumber ( T- L) Neurotransmitter – Adrenaline, Non Adrenaline  

10. P arasympathetic division R eturns the body to normal after the fight-or-flight response has occurred. For example, it slows down the heart rate, narrows air passages in the lungs, reduces blood flow to the skeletal muscles, and stimulates the digestive system to start working again. The parasympathetic division also maintains the internal homeostasis of the body at other times. craniosacral Neurotransmitter – Acetylcholine

11. Somatic Nervous System The  somatic nervous system primarily senses the external environment and controls voluntary activities in which decisions and commands come from the cerebral cortex of the brain In general, the somatic nervous system  is responsible for all of conscious perceptions of the outside world and all of the voluntary motor activities perform in response. Whether it’s playing piano, driving a car, or playing basketball, you can thank your somatic nervous system for making it possible. Structurally, the  somatic nervous system consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves .

12. Cranial nerve There are 12 paair of cranial nerve that leave the skull through various foramina of cranial bone. Cranial nerves are in the head and neck and connect directly to the Brain. some cranial nerve are only sensory or afferent ; others are only motor or efferent. The cranial nerve have both motor and sensory are called mixed nerve.

13. sn Nerve Nature Origin Termination Function olfactory sensory roof of nose temporal lobe conduct nerve impulse of smell ii Optic Sensory Retina Occipital conduct nerve impulse of vision iii Oculomotor Motor Midbrain Eyes Controls movements of eyeball and eyelid Adjusts the lens for near vision and constricts the pupil in bright light Regulates proprioception iv Trochlear nerve (the smallest cranial nerve) Motor Midbrain Eyes Controls movements of eye ball Regulates proprioception v Trigeminal nerve (the largest cranial nerve) Mixed Motor: Pons Sensory: Face, muscles head and teeth Motor: Chewing muscle Sensory: Pons Moter:chewing muscles Sensory: Conduct impulses of pain, temp. and touch to face, head and teeth vi Abducens nerve Motor Pons Eye Controls movements of eye bal

14. Nerve Nature Origin Termination Function facial (VII) mixed motor: Pons senosry: tongue motor: face, neck and scalp sensory: Pons Motor: Controls the mus- cles for facial expression and also controls saliva secretion Sensory: Conducts im- pulses for taste sensation Vestibulocochlear nerve (VIII) (auditory nerve) senosry Inner Ear Cochlear branch: Temporal lobe Vestibular branch: Pons and Cerebellum Cochlear branch: Conducte impulses for hearing Vestibular branch: Conducts impulses for equilibrium. Glossopharyngeal nerve (IX) mixed motor: Medulla oblongata sensory: paratoid gland Sensory: Medulla oblongata motor: tongue `Motor: Control contraction of pharynx and salivary secretion Sensory: Conducts im- pulses for taste sensation Vagus nerve (X) (major parasym- pathetic nerve) mixed motor: Medulla oblongata Sensory: Medulla oblongata

15. Accessory nerve (XI) motor Brain stem and spinal cord muscle of pharynx, layrnyx and neck Regulates movement of head and controls process of swallowing Hypoglossal nerve (XII) motor Medulla oblongata tongue muscles Controls movement of tongue during speaking and swallowing

16. Spinal nerve Spinal nerves of the  somatic nervous system emanate from the spinal column between vertebrae. All of the spinal nerves are mixed nerves, containing both sensory and motor neurons. Spinal nerves also include motor nerves that stimulate skeletal muscle contraction, allowing for voluntary body movements.