CNS & PNS Anatomy (PDF)

Dr. Cristian Martonos 1 Previous lecturer: Dr. Cristian Dezdrobitu “The right half of the brain controls the left half of the body. This means that only left handed people are in their right mind.” https://www.pinterest.com/pin/565483296946963803/ !!! ‘’Pathwa...

Dr. Cristian Martonos 1 Previous lecturer: Dr. Cristian Dezdrobitu “The right half of the brain controls the left half of the body. This means that only left handed people are in their right mind.” https://www.pinterest.com/pin/565483296946963803/ !!! ‘’Pathways of nerve impulses are crossed pathways — meaning that the Left side of the brain controls the RIGHT side of the body, and the Right side of the brain controls the LEFT side of the 2 body’’ !!!  3 https://www.slideshare.net/wyllhy/the-nervous-system-slide-show 4 Role: controls and coordinates all essential functions of the body in the smooth functioning of the different parts of our body without the nervous system we wouldn't be able to think, feel, move or survive the most important function of the nervous system is to integrate and respond to the environment 5 ‘’The detection of environmental changes, their subsequent integration and interpretation, and finally, the production of a behavioral response are the function of the nervous system, incomparably the most complicated of the body systems.’’ DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 6 Function: SENSORY sensory receptors used to monitor changes both inside and outside of the body gathered informations : Sensory input 7 Function: INTEGRATIVE process and interprets the sensory input and takes decisions about what should be done - INTEGRATION MOTOR NS sends informations to the effectors (muscle, glands, internal organs) 8  DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 A simplified receptor: effector neural circuit. 1. Skin receptor; 2, afferent or sensory neuron; 3, synapses on interneuron; 4, interneuron; 5, efferent or motor 9 neuron; 6, striated muscle (effector). 10 DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 11  Brain and spinal cord act like the integrating and command center of the nervous system. Role:  to interpret incoming sensory information and issue instructions based on past experience and current conditions 12 Outside the CNS Carries impulses from the sensory receptors to the CNS and from the CNS to effectors Cranial nerves: to and from the brain Spinal nerves: to and from the spinal cord 13 Divided functionally in:  afferent division (also termed the sensory component, conducts impulses toward the spinal cord and brain)  efferent division (or motor component of the peripheral nervous system conveys impulses away 14from the brain and spinal cord)  Afferent and Efferent  subdivided into the SOMATIC and VISCERAL systems 15  Somatic system  is concerned with both sensory and motor functions that determine the relationship of the organism to the outside world  they include detection of stimuli  in the skin  in the tissues of the limbs and trunk 16  behavioral actions such as locomotion Somatic system  is sometimes referred to as the voluntary system, because there is a greater conscious awareness and greater voluntary control of somatic functions than of the visceral functions 17 Visceral system  concerned with sensory and motor functions that relate to the internal viscera. E.g: the regulation of the blood pressure and heart rate, the control of glandular activity and digestive processes  the motor component of the visceral peripheral nervous system is also referred to as18the autonomic nervous system  Autonomic nervous system: Sympathetic Parasympathetic Most organs receive innervation from both components. The sympathetic and parasympathetic components are often described as having antagonistic actions on each organ, although “balancing” might better describe their cooperative role. Visceral efferent fibers of the sympathetic division leave the central nervous system via the spinal nerves in the thoracolumbar regions of the spinal cord; those of the parasympathetic division are found in a small group of cranial nerves (III, VII, IX, X) and in spinal nerves in the sacral region of the spinal cord. Many visceral efferent fibers travel to their target organ by joining with19other nerves so that they obtain a very widespread peripheral distribution. Somatic Nervous System Autonomic Nervous System Regulates the voluntary movement Regulates the involuntary movement of the body of the body Regulates movements of the body Regulates bodily functions such as via the skeletal muscles, along with respiratory rate, heart rate, urination, sensory stimuli related to vision, smell, digestion, sexual arousal, pupillary taste, pain, noise, touch, and response temperature Made up of the afferent nerves Made up of a complex network of (sensory nerves) and efferent nerves motor neurons, which control glands, (motor nerves) that stimulate skeletal cardiac muscles, and smooth muscle movement muscles Divisions include the sympathetic Divisions include the spinal nerves and the parasympathetic nervous 20 and the cranial nerves system  21 https://www.slideshare.net/wyllhy/the-nervous-system-slide-show  DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 Neurons (nerve cells) are the basic elements of the nervous system. 22  Thin branching extensions of the cell body that conduct nerve impulses toward the cell body Courtesy of Drs Ray Wilhite, Dan Hillmann and Joe Rowe A single branch (in https://www.slideshare.net/itutor/nervous-system-22589837 most neurons) which conducts nerve 23 impulses away from the cell body. CROSS SECTION OF SPINAL 24 CORD  DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 Dorsal view of the spinal cord and the vertebral pedicles of the horse. The spinal cord is shorter than the vertebral canal (ascensus medullae spinalis). (B) Enlargement of the caudal part. 1, Atlas; 2, ilium; 3, sacrum; 4, cervical intumescence; 5, lumbar 25 intumescence; 6, cauda equina.  NERVES Based on the direction of the nerve impulse, there are: Sensory (afferent) nerves Motor (efferent) nerves Mixed nerves = sensory + motor (somatic and/or autonomic) 26 Based on the site of emergence, there are:  Spinal nerves (emerge from the spinal cord)  Cranial nerves (emerge from the brain) NOTE! All spinal nerves are mixed nerves. Not all cranial nerves are mixed nerves. 27 CONSCIOUS DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, PERCEPTION FIFTH EDITION ISBN: 9780323442640 OF SENSORY INPUT AND COORDINATION AND INITIATION FINE TUNING OF OF CONSCIOUS MOVEMENT MOVEMENT CEREBRUM CEREBELLUM BRAINSTEM (midbrain, pons and the medulla oblongata) RELAY CENTER/ FILTERS SENSORY28 INPUT, WHICH ALLOWS US TO CONCENTRATE 29  DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 CEREBRUM CEREBELLUM Enabling communication between hemispheres BRAINSTEM 30 MEDIAN SECTION  CEREBRUM CEREBELLUM BRAINSTEM White matter Gray matter 31  CP T RC CC PG CRANIAL CORD CAUDAL RC CC T CP CN IV 32 BRAINSTEM –dorsal view  OT CN CN II III CRANIAL OC CAUDAL CN II H P MO CORD OT CN III CN VI 33 BRAINSTEM –ventral view  Olfactory (I) Optic (II) Oculomotor (III) Trochlear (IV) Trigeminal (V) Abducens (VI) Facial (VII) Vestibulocochlear (VIII) Glossopharyngeal (IX) Vagus (X) 34 Accessory (XI) Hypoglossal (XII)  35 http://baronerocks.com/images/Anatomy/cranialnerves.jpg  36 https://mindblogger.files.wordpress.com/2010/12/cranialnerves- copy.gif?resize=600%2C400 http://www.scientificanimations.com/wp-content/uploads/2018/05/Cranial- nerves.jpg 37 CRANIAL NERVES MUSIC VIDEO  https://www.youtube.com/watch?v=sAFaTaavmO8 38  Palbebral reflex Menace response http://infovets.com/books/Canine/B/B548.htm Reflex Response requires cortical awareness! Does not require cerebral input Does not imply consciousness 39 This all happens BEFORE you are conscious of it!  Basic neural pathway (reflex arc) 5 Basic Elements of Reflex Arc:  Receptor PNS  Sensory neuron  Integration center  Motor neuron  Effector CNS Afferent Efferent 40 Types of Reflexes based on the NS divisions:  Somatic Reflexes – include all reflexes that stimulate the skeletal muscle (e.g. When you quickly pulled your hand away from a hot object, a somatic reflex is working).  Autonomic Reflexes – regulate the activity of smooth muscles, the heart, and glands (i.e. Secretion of saliva and changes in the size of the eye pupils); autonomic reflexes - regulate such body functions as digestion, elimination, blood pressure and sweating. 41 42  Nerves Based on the direction of the nerve impulse, there are: ? (afferent) nerves Sensory ? (efferent) nerves Motor ? nerves = sensory Mixed ? + motor (somatic and/or ? autonomic) ? Spinal Nerves are mixed All ? nerves Not? all Cranial Nerves are mixed ? nerves 43  Nerves Based on the direction of the nerve impulse, there are: Sensory (afferent) nerves Motor (efferent) nerves Mixed nerves = sensory + motor (somatic and/or autonomic) All Spinal Nerves are mixed nerves Not all Cranial Nerves are mixed nerves 44  Basic neural pathway (reflex arc) PNS ? ? CNS ? Input Output ? 45  Basic neural pathway (reflex arc) PNS CNS Input Output 46 The part of the brain indicated by the arrow is the: A. Right hemisphere and Left hemisphere B. Cerebellum C. Right hemisphere D. Corpus callosum E. Left hemisphere 47 The part of the brain indicated by the arrow is the: A. Right hemisphere and Left hemisphere B. Cerebellum C. Right hemisphere D. Corpus callosum E. Left hemisphere 48  OBJECTIVES  Describe the role of the NS  Describe how the CNS and PNS work  Describe the functions of the NS (3 functions described/slides 6 and 7)  Describe the subdivisions of both CNS and PNS  Describe the role of both CNS and PNS  Understand how the PNS is divided functionally  Understand the difference between SOMATIC and AUTONOMIC  Define the SYMPATHETIC and PARASYMPATHETIC  Define the types of nerves based on the direction of the nerve impulse and based on the site of emergence  Describe the main roles of the Cerebrum, Cerebellum, Brainstem and Corpus Calossum  Have knowledge of the Cranial Nerves and their type (sensory/motor/mixed) – Not responsible for their distribution and role 49  The difference between a reflex and a response  Comprehend the basic elements of the Reflex Arc https://www.bing.com/images/search 50