Peripheral & Autonomic Nervous System Chapter 9

Peripheral Nervous System Page 169 Peripheral Nervous System All the nerves that connect the brain & spinal cord with sensory receptors, muscles, & glands Afferent peripheral system – conveys information from the periphery to the brain & spinal cord Efferent peripheral system – conveys information from the brain & spinal cord to the muscles & glands Somatic – from brain & spinal cord to skeletal muscle Autonomic – from brain & spinal cord to smooth muscle

Efferent Peripheral System Page 169 Efferent Peripheral System Somatic nervous system – Responds to changes in the external environment Autonomic nervous system Sympathetic : fight or flight response (norepinephrine) Parasympathetic: rest and digest response (acetylcholine)

Pages 169 – 170 Nerves Bundles of nerve fibers enclosed by connective tissue Sensory (afferent) nerves Motor (efferent) nerves Mixed nerves Sensory or afferent nerves – carry impulses from the sense organs to the brain or spinal cord Motor or efferent nerves – carry impulses from the the brain or spinal cord to muscles or glands Mixed nerves – if the bundle contains both sensory & motor fibers

Cranial & Spinal Nerves Page ? Cranial & Spinal Nerves Part of the peripheral nervous system 12 pairs of cranial nerves Originate from the brain & brain stem 31 pairs of spinal nerves Direct connection to the spinal cord Plexus Largest spinal nerve: sciatic

Cranial Nerves Page 171 I Olfactory Smell II Optic Vision III Oculomotor Eyelid & eyeball movement IV Trochlear Innervate superior oblique muscle, turns eye downward & laterally V Trigeminal Sensation of face & mouth espcially chewing VI Abducens Turns eye laterally VII Facial Taste & controls most facial expressions, secretion of tears & saliva

Cranial Nerves (Cont’d) Page 171 Cranial Nerves (Cont’d) VIII Vestibulocochlear Hearing & equilibrium IX Glossopharyngeal Taste & controls swallowing, secretion of saliva X Vagus Sensation from the larynx, pharynx, liver, stomach & movement in organs of the thoracic & abdominal area XI Spinal accessory Controls trapezius & sternocleidomastoid muscles XII Hypoglossal Movement of tongue muscles

Spinal Nerve Plexus Page 170 Cervical plexus Brachial plexus Lumbar plexus Sacral plexus

Autonomic Nervous System Page 172 Autonomic Nervous System Nerves, ganglia, & plexuses that carry impulses to all smooth muscle, secretory glands, & heart muscle Sympathetic system – accelerate the heartbeat in response to fear Parasympathetic system – slows the heartbeat down Strongly influenced by emotion They are antagonistic to each other

Sympathetic System Page 172 Fight-or-flight system – meant for acute stress, not chronic stress Consists primarily of two cords, beginning at the base of the brain and proceeding down both sides of the spinal column Nerves extend to all vital organs Learning to cope with stress is essential to preventing overstimulation of this system & the subsequent problems

Parasympathetic System Pages 172 – 175 Parasympathetic System Two important active nerves: Vagus & Pelvic nerves Counteracts effects of the sympathetic nervous system Brings the body back to homeostasis

Reflex Arc Page 175 Simplest type of nervous response It is unconscious & involuntary Every reflex act is preceded by a Stimulus Receptors = special structures that pick up stimuli Response = reaction to stimulus Stimulus = change in the environment

Page 175 Biofeedback Measurement of physiological responses that yields information about the relationships between the mind & the body & helps people learn to manipulate those responses through mental activity Enhances relaxation the use of electronic monitoring of a normally automatic bodily function in order to train someone to acquire voluntary control of that function.

Pages 175 – 176 Disorders Neuritis – inflammation of a nerve. Symptoms may be severe pain, hypersensitivity, loss of sensation, muscular atrophy, weakness, & paresthesia. Sciatica – a form of neuritis that affects the sciatic nerve. Symptom is pain that radiates through the buttocks & behind the knee down to the foot. Peripheral neuropathy – damage to the peripheral nerves. Most commonly caused by diabetes. Neuralgia – sudden, severe, sharp, stabbing pain along the pathway of a nerve. Neuritis – The causes of neuritis may be infectious, chemical, or due to other conditions such as chronic alcoholism. In the patient who is diagnosed with alcoholism, neuritis usually occurs because of a lack of vitamin B or an improper diet. paresthesia (tingling, burning, & crawling of the skin) *****

Disorders (Cont’d) Page 176 Trigeminal neuralgia – cause is unknown, onset is rapid, pain is severe. (fifth cranial nerve Bell’s palsy – condition that involves the seventh cranial nerve. Patient appears as if they have had a stroke. Shingles or herpes zoster – acute viral nerve infection. Characterized by a unilateral inflammation of a cutaneous nerve. Carpal tunnel syndrome – a condition that affects the median nerve & the flexor tendons that attach to the bones of the wrist.

Types of Anesthesia Page 177 SB Local numbing of area Regional anesthesia Spinal anesthesia Epidural anesthesia General anesthesia