Basic Anatomy & Physiology 1 - Nervous System (Part 4) PDF

RNB 10603 BASIC ANATOMY & PHYSIOLOGY 1 TOPIC 5 NERVOUS SYSTEM PART 4: PERIPHERAL NERVOUS SYSTEM (PNS) 1 Recap… Organization of the Nervous System 2  LEARNING OUTCOMES At the end of the session, the studen...

RNB 10603 BASIC ANATOMY & PHYSIOLOGY 1 TOPIC 5 NERVOUS SYSTEM PART 4: PERIPHERAL NERVOUS SYSTEM (PNS) 1 Recap… Organization of the Nervous System 2  LEARNING OUTCOMES At the end of the session, the students should be able to:  list the parts that form the peripheral nervous system;  describe the spinal nerves;  describe the cranial nerves;  explain the autonomic nervous system. 3  PERIPHERAL NERVOUS SYSTEM  Branch out from the brain and spinal cord  Include all nervous tissue outside the CNS  Consists of: ✓ Spinal nerves – 31 pairs ✓ Cranial nerves – 12 pairs ✓ The autonomic nervous system (ANS) 4 Spinal Nerves 5  SPINAL NERVES  Spinal nerves & their branches connected to the spinal cord by posterior and anterior root  They connect the CNS to the sensory receptors, muscles and glands in all parts of the body  The 31 pairs of spinal nerves are named and numbered according to the region and level of the vertebral column from which they emerged 6  SPINAL NERVES  31 pairs  8 cervical (C1 – C8)  12 thoracic (T1 – T12)  5 lumbar (L1 – L5)  5 sacral (s1 – S5)  1 coccygeal 7 SPINAL NERVES 8  SPINAL NERVES  Spinal nerve has two connection:  Posterior root (contains sensory axon)  Anterior root (contains motor axons)  The posterior & anterior roots unite to form a spinal nerve (mixed nerve)  The posterior root ganglion (contains cell bodies of sensory neuron) 9  SPINAL NERVES Protective Covering ◼ Spinal nerve contains layers of protective connective tissue coverings ✓ Endoneurium – wrapped a single axon ✓ Perineurium – wrapped a fascicle (a bundle of axon) ✓ Epineurium – the outer covering of nerve ◼ There are many blood vessels which nourish the nerves within the perineurium & epineurium 10 SPINAL NERVES Protective Covering 11  SPINAL NERVES Plexuses  Spinal nerves branch after pass through the intervertebral foramina (holes between vertebrae)  In the cervical, lumbar and sacral region, the spinal nerves join with branches from the neighboring nerves to form a larger nerve called plexuses  The nerve names relate to the region they supplied  Thoracic nerves DO NOT form plexuses 12  SPINAL NERVES Plexuses 5 main plexuses:  Cervical plexuses  Brachial plexuses  Lumbar plexuses  Sacral plexuses  Coccygeal plexuses 13  SPINAL NERVES Plexuses  Cervical plexus  Supplies posterior head, neck, shoulders, and diaphragm  Important nerves: phrenic nerves which stimulate diaphragmn to contract – damage cause respiratory failure  Brachial plexus  Supplies upper limbs + some neck and shoulder muscles  Important nerves: radial, ulnar, axial, median to arm, forearm, hand 14  SPINAL NERVES Plexuses  Lumbar plexus  Supplies abdominal wall, external genitalia, and part of lower limbs  Important nerves: femoral (to anterior thigh)  Sacral plexus  Supplies buttocks, perineum, and most of lower limbs  Important nerves: gluteal, sciatic (to posterior thigh and all of leg and foot, the longest nerve in the body) 15 16 17 Dermatome The nerves arising from each region of the spinal cord and vertebral column supply specific body regions. A dermatome is the area of skin supplied with sensory innervation by a pair of spinal nerves. Each spinal nerve except C1 has a specific cutaneous sensory distribution. Dermatome Dermatome Cranial Nerves 21  CRANIAL NERVES  Consist of 12 pairs of cranial nerves  Designated with roman numerals (indicate the order the nerves emerge from the brain)  Cranial nerves I, II & VIII: sensory nerves  Cranial nerves III, IV, VI, XI, & XII: motor nerves  Cranial nerves V, VII, IX, & X: mixed nerves 22 I. Olfactory (sensory) II. Optic (sensory) III. Oculomotor (motor) IV. Trochlear (motor) V. Trigeminal (mixed) VI. Abducens (motor) VII. Facial (mixed) VIII. Vestibulocochlear / auditory (sensory) IX. Glossopharyngeal (mixed) X. Vagus (mixed) XI. Accesory (motor) XII. Hypoglossal (motor) 23 24 No Name Functions I Olfactory Smell II Optic Vision III Oculomotor Eye movement; Pupil dilataion IV Trochlear Eye movement V Trigeminal Somatosensory information fr the face & head; chewing VI Abducens Eye movement VII Facial Taste (anterior 2/3 of tougue); somotosensory info fr ear; contorl muscles used in facial expression VIII Vestibulo-cochlear Hearing; balance IX Glossopharyngeal Taste (posteriro 1/3 tongue); somatosensory info fr tongue, tonsils, pharynx; contorol muscles for swallowing X Vagus Sensory, motor & autonomic functions of viscera XI Spinal accessory Controls muscles used in head movement XII Hypoglossal Controls muscles of tongue 25 I. Olfactory (Sensory) Mnemonics to help you II. Optic (Sensory) remember III. Oculomotor (Motor) On Old Olympus IV. Trochlear (Motor) V. Trigeminal (Both) Towering Top A Fin VI. Abducens (Motor) And German Viewed VII. Facial (Both) Some Hops VIII. Vestibulocochlear / Auditory (Sensory) S (sensory) M (Motor) IX. Glossopharyngeal B (Both sensory & motor) (Both) X. Vagus (Both) Small Ships Make XI. Accesory / Spinal Money, But My accesory (Motor) Brother Says Big XII. Hypoglossal (Motor Boats Make More 26 AUTONOMIC NERVOUS SYSTEM (ANS) 27  AUTONOMIC NERVOUS SYSTEM  Peripheral nervous system (PNS)  Somatic nervous system (SNS)  Autonomic nervous system (ANS)  ANS is NOT under conscious control, regulated by by hypothalamus and brainstem  The ANS supplies nerves to the viscera  Smooth muscle (stomach, blood vessels)  Cardiac muscle (heart)  Glands (sweat and digestive glands) 28  AUTONOMIC NERVOUS SYSTEM  Autonomic motor pathway has two neurons  The 1st neuron’s cell bodies is in the brain or spinal cord  Its axon, the preganglionic fiber leaves the CNS & synapse with a 2nd neuron in an autonomic ganglion 29  AUTONOMIC NERVOUS SYSTEM  The 2nd neuron cell body is located in the autonomic ganglion  The axon of 2nd neuron, the postganglionic fiber leaves the ganglion & goes to the effector organ 30 ANS Motor Pathways 31  DIVISION OF THE ANS  ANS has 2 division:  Sympathetic division (S)  Parasympathetic division (p)  Most viscera supplied with nerves of both sympathetic and parasympathetic divisions: dual innervation  Sympathetic and parasympathetic have opposite (antagonistic) effects, for example:  Heart rate: S - stimulates, P - inhibits  Digestive organs: S - inhibit, P - stimulate 32  DIVISION OF THE ANS Sympathetic Division  Concerned in preparing the body for stressful or emergency situation  Also called “fight or flight” system – an energy- expending system  Stimulated by “4E situations” (Exercise, Excitement, Emergency, Embarrassment)  Example in emergency situation – ↑ heart rate, breathing rate & blood flow to skeletal muscle; at the same time digest system activity ↓ 33  DIVISION OF THE ANS Sympathetic Division  The effects are longer-lasting and more widespread than those of the parasympathetic stimulation  Hormones adrenalin (epinephrine) & noradrenalin is secreted into the bloodstream as the effect of sympathetic stimulation 34  DIVISION OF THE ANS Sympathetic Division Specific sympathetic responses include:  Pupils dilate  Heart rate and blood pressure increase  Blood flow to the kidneys and gastrointestinal tract diminishes  Blood flow to the skeletal muscles, liver, heart and adipose tissue increases  Liver cells release glucose and adipose cells break down fat to increase available energy 35 Sympathetic Division 36  DIVISION OF THE ANS Parasympathetic Division  Responsible for stimulation of “rest-and-digest” activities occur when body at rest & relax  Slowdown the body process except digestion & absorption of food & function of genitourinary function  The effects are last for a shorter time and are less widespread than those of the sympathetic stimulation 37 Parasympathetic (P) Division 38 Craniosacral Thoracolumbar 39 40 Clinical disorders  Traumatic brain injuries – Concussion, Contusion  Strokes  Alzheimer’s disease  Neural tube defect  Anencephaly  Spina bifida  Paraplegia  Quadriplegea  Myelitis  Cerebral palsy  Microcephaly 41 42 THANK YOU 43