Grade 10 Nervous System Divisions Lesson 2 PDF

# NERVOUS SYSTEM - Function of somatic and autonomic nervous system ## NERVOUS SYSTEM - **DEFINITION** - The network of nerve cell and fiber which transmit nerve impulses between parts of the body. ## DIVISION OF NERVOUS SYSTEM - Diagram of nervous system broken down into: - Nervous System...

# NERVOUS SYSTEM - Function of somatic and autonomic nervous system ## NERVOUS SYSTEM - **DEFINITION** - The network of nerve cell and fiber which transmit nerve impulses between parts of the body. ## DIVISION OF NERVOUS SYSTEM - Diagram of nervous system broken down into: - Nervous System - Central nervous system (brain and spinal cord) - Peripheral nervous system - Autonomic nervous system (communicates with internal organs and glands) - Sympathetic division (arousing) - Parasympathetic division (calming) - Somatic nervous system (communicates with sense organs and voluntary muscles) - Sensory (afferent) nervous system (sensory input) - Motor (efferent) nervous system (motor output) ## SOMATIC NERVOUS SYSTEM - Voluntary nervous system - **DEFINITION** - Part of the peripheral nervous system associated with the voluntary control of body movement via skeletal muscles. ## WORKING - Diagram of a neuron labeled: Dendrites, Nucleus, Soma (cell body), Axon terminals, Myelin Sheaths, Axon - 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. ## SENSORY DIVISION - Diagram of the central and peripheral nervous system, labeled: Brain, Spinal cord, Cranial nerves, Ganglia outside CNS, Spinal nerves - 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. ## SENSORY RECEPTORS - sensory receptors are cells that send information about changes in external as well as internal environment. - These changes are called STIMULI - Diagram of sensory receptors labeled: - Free nerve endings (pain, heat, cold), Merkel disks (touch), Krause end bulbs (touch), Root hair plexus (touch), Meissner corpuscles (touch), Pacinian corpuscles (pressure), Ruffini endings (pressure) ## CATEGORIZATION OF SENSORY RECEPTORS | Type | Responds to | Some Locations | | ------------- | --------------- | -------------------------------------------------- | | Chemoreceptor | Chemicals | Mouth, nose, blood vessels | | Photoreceptor | Light | Eyes | | Mechanoreceptor | Touch, pressure, vibrations, and stretch | Skin, hair follicles, ears, ligaments, tendons | | Thermoreceptor | Temperature changes | Skin, hypothalamus | | Pain receptor | Tissue injury | Throughout the body | ## MOTOR DIVISION - Diagram of a brain with arms lifting weights - Once it has gathered and processed sensory information, the nervous system sends commands to the rest of the body. - The motor division of the peripheral nervous system transmits impulses from the central nervous system to muscles or glands. - MOTOR = CNS - Neuron - Muscle or gland. - These messages are relayed through one of two divisions, the somatic nervous system or the autonomic nervous system. ## TYPES OF NERVES ## SPINAL NERVES - 31 pairs and 62 spinal nerves. - Each spinal nerve has a VENTRAL ROOT and a 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 ## CRANIAL NERVES - Diagram of the brain labeled: Frontal pole, Temporal pole, Pituitary gland, Mamillary bodies, Trigeminal ganglion, Cerebello-pontine angle, Cerebellum, Olfactory bulb and peduncle, 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. ## Diagram of cranial nerves - Labeled: - Sensory fibers, Motor fibers, Optic (II) sensory: eye, Olfactory (I) sensory: nose, Intermediate motor: submaxillary and sublingual gland, Sensory: anterior part of tongue and soft palate, Intermediate nerve, Vestibulocochlear (VIII) sensory: inner ear, Glossopharyngeal (IX) motor: pharyngeal musculature, Sensory: posterior part of tongue. Tonsil, pharynx, Trochlear (IV) motor: superior oblique muscle, Abducent (VI) motor: external rectus muscle, Oculomotor (III) motor: all eye muscles except those supplied by IV and VI, Vagus (X) motor: heart, lungs, bronchi, gastrointestinal tract, Sensory:, heart, lungs, bronchi, trachea, larynx, pharynx, gastrointestinal tract, external ear, Trigeminal (V) sensory: face, sinuses, teeth, etc. Motor: muscles of mastication, Facial (VII) motor: muscles of the face, Hypoglossal (XII) motor: muscles of the tongue, Accessory (XI) motor: sterno cleidomastoid and trapezius muscles ## REFLEX ARCS - Diagram of a hand grasping a hot object and a hand on a tack - 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. ## REFLEX ARCS - Diagram of a leg on a tack labeled: Sensory neuron, Interneuron, Spinal cord, Effector (responding muscle), Sensory receptors - 1. Sensory receptors react to the sensation of the tack and send an impulse to sensory neurons. - 2. Sensory neurons relay the information to the spinal cord. - 3. An interneuron in the spinal cord processes the information and forms a response. - 4. A motor neuron carries impulses to its effector, a muscle that it stimulates. - 5. The muscle contracts and your leg moves. ## The knee jerk is a reflex action - Diagram of a doctor checking a knee jerk reflex. ## 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. ## PROPERTIES OF ANS - Diagram of 4 colored circles: - Red: ANS also operate through visceral reflexes receiving subconscious sensory signals from the visceral organs. - Yellow: It is a motor system for visceral organs, blood vessels and secretory glands. - Purple: PREGANGLIONIC NERVE: cell body in spinal cord or brain stem and myelinated thin axon fiber in ganglia. - Blue: POSTGANGLIONIC NERVE: cell body is in the ganglia and non myelinated axon in the visceral effector cell. ## Autonomic pathways consist of two neurons that synapse in an autonomic ganglion. - Diagram of autonomic pathways labeled: CNS, Preganglionic neuron, Postganglionic neuron, Autonomic ganglion, Target tissue ## FIGURE 11-4 - Autonomic pathways - Diagram of central nervous system, labeled: 2-neuron system, Ganglion, Preganglionic, Postganglionic , Smooth muscle, Cardiac muscle, Glands, Autonomic nervous system ## SYMPTHATIC NERVOUS SYSTEM ## PARASYMPATHETIC NERVOUS SYSTEM ## Homeostasis is a dynamic balance between the autonomic branches. - Diagram of a seesaw with red line on left side labeled Parasympathetic and blue line on the right side labeled Sympathetic. People are on each side representing parasympathetic and sympathetic, and a snake represents the sympathetic side. - Rest-and-digest: Parasympathetic activity dominates. - Fight-or-flight: Sympathetic activity dominates. ## PARASYMPATHETIC NERVOUS SYSTEM - 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. ## Diagram of a character from the show Spongebob Squarepants labeled: REST, RELAX, RUMINATE ## SYMPAHETIC NERVOUS SYSTEM - 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. ## FIGHT or Flight - Diagram of 2 cartoon characters. One is punching, labeled: Stand your ground, defend your position, attack, dig in. The other is running away, labeled: Give way, retreat, discard, remove yourself, give up. ## Diagram of Parasympathetic and Sympathetic nervous systems - Left side, labeled Parasympathetic: - Eyes Constrict Pupil - Salivary Glands Stimulates Salivation - Heart Slows Heartbeat - Lungs Constrict Bronchi - Stomach Stimulates Digestion - Liver Stimulates Bile Release - Intestines Stimulate Peristalsis and Secretion - Bladder Contracts - Right side, labeled Sympathetic: - Eyes Dilate Pupul - Salivary Glands Inhibit Salivation - Heart Accelerates Heartbeat - Lungs Dilate Bronchi - Stomach Inhibits Digestion - Liver Stimulates Glucose Release - Kidneys Stimulate Epinephrine and Norepinephrine Release - Intestines Inhibit Peristalsis and Secretion - Bladder Relaxes Bladder - Center of Diagram: - Ganglion - Medulla Oblongata - Vagus Nerve - Chain of Sympathethic Ganglia - Solar Plexus - **Schema Explaining How Parasympathetic and Sympathetic Nervous Systems Regulate Functioning Organs** ## Thank You So Much - Diagram of a blue butterfly ## Diagram of a question mark made of the words: - Which, where, when, how, why, what, who