L1_ Anatomical Structures and Physiology of the Human Nervous System.pdf

Anatomical Structures and Physiology of the Human Nervous System Ligia Westrich, Ph.D., R.Ph. August 26, 2024 [email protected] Learning Objectives  Identify the major structures of the brain and spinal cord and their functions  Differentiate betwe...

Anatomical Structures and Physiology of the Human Nervous System Ligia Westrich, Ph.D., R.Ph. August 26, 2024 [email protected] Learning Objectives  Identify the major structures of the brain and spinal cord and their functions  Differentiate between central and peripheral nervous systems  Identify and describe the functions of CNS tracts and PNS nerves mssterfects  Compare and contrast the somatic and autonomic nervous systems  Discuss events that occur at the neuromuscular junction  Describe protective structures and blood supply of the nervous system 2  unteafs can make connectionne them btw matter is Sensory – detection grey where all booker Integration – processing Motor – execution (response) are 3  The Cerebral Cortex both left Central crosseamsperous hemisphempotent Parietal Sensory input: Movement sulcus Frontal lobe touch, sensation Decision making lobe and proprioception Problem solving Motivation perception Rationality of bodyparts Personality Memory Occipital lobe Vision Temporal lobe Hearing Cerebellum Memory, Emotion (regulates motor movements) (posture, balance, coordination and speech) hippocampus 4 INPUT  PROCESS  OUTPUT  The Cerebral Cortex Integration of information derived from other brain regions (external stimuli/internal motivation), identification of significance, planning of a meaningful response/generation of behavior = “Cognition” 5 The Cerebral Cortex needto know dotted lines boutonniere talking front motor area Broca’s area: initiation of speech understand but won't be able damage they may to talk back 6 Wernicke’s area: understanding spoken and written language Three Major Planes of the Brain white matter axons agrey matter All body corpuscallosum Fibers astrolabes 8 Three Major Planes of the Brain 9  Subcortical Structures (Limbic system: emotion, learning and memory) all info that comes from except for (Basal ganglia: spinal cord gothrough here regulates and auditory visual relay center adjust movement) 10 Ventricular System of the Brain b vessels that line ventricles USF makes receptor zones were trigger 11 Ventricular System of the Brain can use spinal tap to tell if there's anything wrong w spinal fluid CSF flows through the lateral ventricles, 3rd & 4th ventricles, subarachnoid space and spinal cord central canal  absorbed into the venous system Functions: protection, buoyancy, chemical stability, nutrition 12 Central Nervous System (Midbrain) 13 Central Nervous System  I. Forebrain  A. Telencephalon  Cerebrum (neocortex) – gyri (convolutions), sulci, and fissures, gray matter and white matter; divided into 4 lobes  Basal ganglia (BG) – striatum (caudate/putamen), globus pallidus (externa & interna), substantia nigra (compacta and reticulata, in the midbrain), nucleus accumbens and subthalamic nucleus Together with cerebellum, BG regulates and modifies movement on a continuous basis  Limbic system – hippocampus, amygdala, limbic cortex (cingulate gyrus) and septal area Learning and memory, control of emotional responses 14  Central Nervous System  I. Forebrain cont’d  III. Hindbrain  B. Diencephalon (inner brain)  A. Metencephalon  Epithalamus (pineal gland)   Thalamus (relay station) Hypothalamus (controls pituitary Tpression  Cerebellum (movement; balance)  Pons (reticular formation; controls breathing, communication between gland via hormones; regulates different parts of the brain, and feeding, body temperature, circadian sensations: hearing, taste, and rhythms) balance)  II. Midbrain (Mesencephalon)  B. Myelencephalon  Corpora quadrigemina (tectum)  Medulla oblongata (regulates BP,  Superior and inferior colliculi (vision and hearing) Tanimoto it breathing, digestion, swallowing)  Tegmentum  Red nucleus and substantia nigra  Basis pedunculi 15 The 3 Human Brains medulla ponsand cerebellum) controls I. The reptilian brain (hindbrain: brain stem basic life processes such as respiration, heart rate and learned rote movements  reliable, but rigid and compulsive II. The limbic (animal) brain (hippocampus, amygdala, cingulate gyrus, thalamus, hypothalamus, basal ganglia) connects the lower and higher (learning and memory, reason, feelings, desire and pleasure) functions of the brain  “helps” us make decisions and react/behave, often subconsciously, based on past experiences III. The neocortex (“new shell”) – primate brain (two large cerebral hemispheres) is responsible for consciousness, imagination, abstract thought, language, planning, perception, movement, opinion, pain, memory and reason, planning and execution of personally and socially suitable behavior  flexible with ∞ learning capabilities. 16 Cortical Homunculus  Somatotopic representation of compartmentalization of functional areas of the body  Distorted because it is based on the proportion of neurons dedicated to the function of the body part represented  It is not based on the size of the actual organ/body area that sends or receives information from the brain  Sensory homunculus  Areas with high input FROM the respective organs: ____  Motor homunculus  Areas with high projections TO respective organs: ____ 17  connects brain body Spinal Cord cellbodies soft comb Of axons  Lies within the vertebral canal and is protected by the vertebral column hard  Connects the brain and the body  Conducts somatic and autonomic reflexes  Provides motor pattern control centers  Modulates sensory and motor function  Sections Vertebral  Cervical, thoracic, lumbar, and sacral canal  Horns  Posterior  Lateral  Anterior 18 Vertebrae  Relays sensory Spinal Cord information to the brain Relays motor information to skeletal muscles 19 Spinal Cord Posterior root relays sensory information to the brain Anterior root relays motor information to skeletal muscles Blue = sensory neurons Red = motor neurons Purple = interneuron connecting sensory and motor neurons in SC Green = autonomic neurons 20 Tortora Principles of A&P 13e Motor staff Spinal Tracts Pyramidal tract duelment Extrapyramidal i.fm (movement) tracts (motor and postural control) 21  Sensory Spinal Tracts Pain, temp, Proprioception, itch, touch deep touch, visceral pain 22 Good to know…  Primary versus association cortices  The 4 lobes of the brain and primary functions  The major planes of the brain  The ventricular system of the brain  Subcortical structures and functions (thalamus, hypothalamus, basal ganglia, hippocampus, amygdala)  Somatic and motor areas of the brain  Spinal sensory and motor tracts 23 CNS  PNS  Central nervous system (CNS)  Brain and spinal cord  Peripheral nervous system (PNS)  Cranial nerves  Spinal nerves  Pathways  Afferent (ascending; sensory and autonomic: periphery to spinal column)  Efferent (descending; motor and autonomic: innervate effector organs)  Somatic nervous system  Motor (efferent) and sensory (afferent) pathways regulating voluntary motor control of skeletal muscle  Autonomic nervous system (ANS)  Autonomic efferent and afferent pathways regulating the body’s internal environment through involuntary control of organ systems  Sympathetic and parasympathetic NS 24  Peripheral Nervous System  12 pairs of cranial nerves  Sensory, motor, and mixed  31 pairs of spinal nerves  Names correlate with the vertebral level from which they exit  Mixed nerves  Arise from the anterior and posterior horn cells of the spinal cord 25  26 https://www.earthslab.com/anatomy/peripheral- nervous-system-pns-cranial-nerves-reflexes/ PNS - Cranial Nerves (12) Sensory (3): Olfactory (I, smell); Optic (II, vision);Vestibulocochlear (VIII, hearing and balance) Motor (4): Trochlear (IV, innervates eyeball muscle); Abducens (VI, eyeball muscle); Accessory (XI, muscle in the back and shoulders); Hypoglossal (XII, innervates the muscles of the throat and enables us to swallow) Mixed (5, sensory, motor and parasympathetic functions): Oculomotor (III, eyeball muscles  dilation/constriction) Trigeminal (V; sensory input from the face, cornea, mouth, nose; motor innervation to the muscles of mastication) Facial (VII; carries taste sensation from the anterior 2/3 tongue; motor function to the muscles of facial expression  facial droop if damaged; parasympathetic input to the salivary and lacrimal glands) Glossopharyngeal (IX; carries taste sensation from the posterior 1/3 tongue and general sensation from the auditory tube and pharynx; parasympathetic input to the parotid gland) Vagus (X; general sensory and motor function to the larynx and pharynx; parasympathetic input to the heart, lungs and GIT) 27 PNS – Spinal Nerves Peripheral Nervous System Somatic Nervous System Autonomic Nervous System ***Voluntary actions*** ***Involuntary functions*** - Somatosensory fibers - Visceral sensory - Somatic motor fibers - Visceral motor Sympathetic Parasympathetic Division Division “Fight or Flight” “Rest and Digest” 29 PNS – Spinal Nerves 30 The Stretch Reflex 31 Tortora Principles of A&P 13e Neuromuscular Junction (NMJ) 32 Tortora Principles of A&P 13e Autonomic Nervous System  Located in both the CNS and PNS  Coordinates and maintains a steady state among the visceral (internal) organs  Neurons  Preganglionic (myelinated)  Postganglionic (unmyelinated)  Two divisions  Sympathetic (pre- and postganglionic)  Parasympathetic (pre- and postganglionic) 33 Sympathetic Nervous System  Mobilizes energy stores in times of need  “Fight or flight response”  Receives innervation from cell bodies located between the first thoracic and the second lumbar region of the spinal cord  Thoracolumbar division  Sympathetic (paravertebral) ganglia  Sympathetic preganglionic fibers  Release acetylcholine (Ach) that simulates nicotinic acetylcholine receptors (nAChR) on postganglionic fibers  Sympathetic postganglionic fibers  Release norepinephrine (NE) on organs that contain α- and β- adrenergic receptors (exception: sweat glands, where Ach is released and it stimulates mAChR) Co muscarinic 34 https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and- physiology/introduction-to-muscles/v/autonomic-somatic-nervous-system Parasympathetic Nervous System  Functions to conserve and restore energy  “Rest or repose response,” “rest and digest”  Receives innervation from cell bodies located in the cranial nerve nuclei and sacral region of the spinal cord  Craniosacral division  Preganglionic neurons travel to ganglia close to the organs they innervate  Parasympathetic preganglionic fibers  Release acetylcholine (Ach) that simulates nicotinic acetylcholine receptors (nAChR) on postganglionic fibers  Parasympathetic postganglionic fibers  Release acetylcholine (Ach) on organs that contain muscarinic receptors (mAChR) 35 https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and- physiology/introduction-to-muscles/v/autonomic-somatic-nervous-system Projection of Sympathetic Preganglionic and Postganglionic Neuronal Fibers Fig 13-2 36  Sympathetic Parasympathetic Sympathetic and Parasympathetic Nervous System Red lines = cholinergic nerves Blue lines = noradrenergic nerves Solid lines = preganglionic nerves Dashed lines = postganglionic nerves 37 Fig 13-3 Neurotransmitters and Neuroreceptors of the PNS 38 Blood Supply to the Brain  800 to 1000 ml per minute  CO2 is the primary regulator for CNS blood flow  Internal carotid and vertebral arteries  Arterial circle (circle of Willis)  Blood-brain barrier (BBB) 40 Peripheral versus CNS Capillaries (BBB) 41 Blood Supply to the Brain me begged Brain spinalcord 42 Blood Supply to the Brain 43 Blood Supply to the Brain 44 Blood Supply to the Spinal Cord  Vertebral arteries  Anterior spinal arteries  Posterior spinal arteries  Aorta 45 Good to know…  PNS structures and functions  Reflex arc  NMJ events  Cranial nerves – basic functions  Somatic NS (sensory, motor, interneuron)  Autonomic NS (sympathetic and parasympathetic)  The protective structures of the brain and spinal cord  The major arteries that supply blood to the brain and spinal cord 46