Anatomy and Physiology - Module 8 - The Nervous System PDF

YEAR ANATOMY AND PHYSIOLOGY 01 MC2 | MS. DEMYBHELLE VISAYA, RN LESSON 08: THE NERVOUS SYSTEM FUNCTIONS OF NERVOUS SYSTEM Enteric Nervous System: a...

YEAR ANATOMY AND PHYSIOLOGY 01 MC2 | MS. DEMYBHELLE VISAYA, RN LESSON 08: THE NERVOUS SYSTEM FUNCTIONS OF NERVOUS SYSTEM Enteric Nervous System: a specialized nervous system - Maintaining homeostasis. found only in the digestive tract. - Receiving sensory input. - Integrating information. CELLS OF THE NERVOUS SYSTEM - Controlling muscle and glands. - Establishing and maintaining mental activity. - Neurons o Receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs. - Glial Cells o Supportive cells of the CNS and PNS, meaning these cells do not conduct action potentials. Instead, glial cells carry out different functions that enhance neuron function and maintain normal conditions within nervous tissue. NEURONS - Also called “nerve cells” that are highly specialized to transmit messages. It has: A. CELL BODY - The metabolic center of the neuron. - It contains a single nucleus. MAIN DIVISION OF NERVOUS SYSTEM - Nissl bodies and neurofibrils are abundant and primary site of protein synthesis in neurons. 1. CENTRAL NERVOUS SYSTEM B. DENDRITES - Includes the brain and spinal cord. - Cytoplasmic extension from the cell body, that usually - The control center, responsible for processing information. receives information from other neurons and transmit the - Interpret incoming sensory information. information to the cell body. 2. PERIPHERAL NERVOUS SYSTEM o Pain receptor: least specialized of the cutaneous - Includes all the parts of the nervous system outside the receptors. CNS. o Proprioceptors: detect the amount of stretch or - Consists mainly of the nerves. tension in skeletal muscles. It is also a receptor - Spinal nerves carry impulses to and from the spinal cord. cell that is sensitive to a stimulus. o Proprioception: ability of the nervous system to - Cranial nerves carry impulses to and from the brain. sense the body’s position in space and movement - Two principal subdivisions of PNS: through space. o A. Sensory / Afferent division: conducts action C. AXON potentials from sensory receptors to the CNS. o B. Motor / Efferent division: conducts action - Single axon rises from a cone – shaped area of the neuron potentials to effector organs, such as muscles and cell body called the axon hillock. glands. o Trigger zone: combination of axon hillock and § Two subdivisions of Motor: initial segment. o Axoplasm: cytoplasm of an axon. a. Somatic Nervous System: o Axolemma: plasma membrane of an axon. allows us to consciously, or o Synaptic cleft: A tiny gap that each axon is voluntarily control our skeletal separated from the next neuron. muscles. Stretch reflex are o Synapse: Such a functional junction, where an initiated involuntarily. impulse is transmitted from one neuron to another. b. Autonomic Nervous System: regulates events that are automatic, involuntary, such as the activity of smooth muscle, cardiac muscle, and glands. o Sympathetic: prepares the body for stress (fight or flight) o Parasympathetic: helps the body relax (rest and digest) MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER 1  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN FUNCTIONAL TYPES OF NEURONS - Phagocytize necrotic tissue, microorganisms, and other 1. SENSORY NEURONS / AFFERENT foreign substances. - Neurons that conduct action potentials toward the CNS. - Perform phagocytosis of dead cells and pathogens. 2. MOTOR NEURONS / EFFERENT 3. EPENDYMAL CELLS - Neurons that conduct action potentials away from the CNS. - Lines the cavities of brain and central canal of spinal cord. 3. INTERNEURONS - Specialized ependymal cells and blood vessels form - Neurons that conduct action potentials within the CNS from structures called choroid plexus. It secretes the CSF that one neuron to another. flows through the ventricles of the brain. - Have patches of cilia that help circulate CSF through the STRUCTURAL TYPE OF NEURONS brain. 1. MULTIPOLAR NEURONS 4. OLIGODENDROCYTES - Most common structural type. - Have cytoplasmic extensions that can surround axons. - Have many dendrites and a single axon - It wraps their flat extension tightly around the nerve fibers, 2. BIPOLAR NEURONS producing fatty insulating coverings called myelin sheaths. - It has two processes: one dendrite and one axon. - Located in some sensory organs, such as in the retina of TYPES OF PNS GLIAL CELLS the eye, and in the nasal cavity. 1. SCHWANN CELLS 3. PSEUDO – UNIPOLAR NEURONS - Form the myelin sheaths around nerve fibers in the PNS. - Have a single process extending from the cell body, which - Gaps in the myelin sheath are nodes of Ranvier. have two branches; one branch extends to the CNS, and - This part of the Schwann cell, external to the myelin sheath, other extends to the periphery. is called the neurilemma. 2. SATELLITE CELLS - Act as protective, cushioning cells for peripheral neuron cell bodies. ORGANIZATION OF NERVOUS TISSUE - Bundle of nerve fibers running through the CNS called tracts, whereas in the PNS are called nerves. - White matter: o Consists of dense collections of myelinated fibers (tracts). - Gray matter: GLIAL CELLS o Consists mostly unmyelinated fibers and cell bodies. - Major supporting cells in the CNS. BLOOD BRAIN BARRIER - Help from a protective permeability barrier between the blood and the brain, and spinal cord, phagocytizes foreign - Specialized permeability barrier between the capillary endothelium (inner lining of the blood vessel) and the substances, produce CSF, and form myelin sheaths. extracellular space in neural tissue. - Formed by tight junctions between capillary and endothelial TYPES OF CNS GLIAL CELLS cells, which are surrounded by “end – fee” processes of 1. ASTROCYTES astrocytes. - Abundant star – shaped. - Protects the vessels that passes through brain from the - Have an extensive cytoskeleton of microfilaments, which toxins or excess substances from the blood that are not enables them to form a supporting framework for blood needed. vessels and neurons. - Help regulate the composition of extracellular brain fluid. PHYSIOLOGY OF IMPULSE CONDUCTION - Form a living barrier between capillaries and neurons, help - Neurons have two major functional properties: determine capillary permeability. o Irritability: ability to respond to stimulus and - Form the blood – brain – barrier. convert it into nerve impulse. 2. MICROGLIA o Conductivity: ability to transmit the impulse to - CNS – specific immune cells. other neurons, muscles, and glands. - Become mobile and phagocytic in response to 1. Resting membrane is polarized. inflammation. 2. Stimulus initiates local depolarization. 3. Depolarization and generation of an action potential. 2 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN 4. Propagation of the action potential. - Needs sodium potassium pump to re – establish RMP (- 5. Potassium ions diffuse out of the cell as the membrane 70mv). permeability changes again, restoring the negative SYNAPSE charge on the inside of the membrane and the positive - Junction point from one neuron to another neuron. charge on the outside surface. - Functional inter neuronal communication occurs. 6. Initial ionic conditions restored. - Impulse reaches axon terminals. RESTING MEMBRANE POTENTIALS - Triggers neurotransmitter release into synaptic cleft. - Terminal buttons or bouton: end of an axon. - Charge difference across the plasma membrane of an - Sites of Synapses: unstimulated cell. o Axoaxonic – axon to axon. o The membrane remains at rest. o Axosomatic – axon to soma. - The resting membrane potential is the result of three o Axodendritic – axon to dendrite. factors: 1. The concentration of K+ inside the plasma CENTRAL NERVOUS SYSTEM membrane is higher than that outside the plasma membrane; - Consists of the brain and the spinal cord. § Membrane is at rest if K is higher inside. 2. The concentration of Na+ outside the plasma TYPES OF NERVE FIBERS membrane is higher than that inside the 1. Somatic Afferent Fibers – convey impulses from the head, plasma membrane. body wall, extremities to the CNS. § Na is higher outside. 2. Somatic Efferent Fibers – convey impulses from the CNS 3. The plasma membrane is more permeable to to the striated voluntary muscles. K+ than to Na+. 3. Visceral Afferent Fibers – convey impulses from the - RMP is -70 millivolts in a neuron. internal organs to CNS. 4. Visceral Efferent Fibers – convey impulses from CNS to - An unequal distribution of ionic charge across the internal organs, glands, smooth and cardiac muscles. membrane is essential for neurons to be excitable. DEVELOPMENT OF THE CNS PHYSIOLOGY OF NERVE IMPULSE - Ectoderm – germal layer that forms the CNS. - Nerve cell fiber resting potential. o Ectoderm – form embryo; forms the skin and the o Na+ concentration higher on outside. nervous system. o K+ concentration higher on inside. o Mesoderm – forms the muscles, bones, and blood o Negative charge on inside. vessels. o Positive charge on outside. o Endoderm – internal organs. 1. Formation of the Neural tube (Days 18 – 26) ACTION POTENTIAL o Neural plate ® Neural Groove ® Neural folds ® - The inside of the plasma membrane becomes positively Neural crest ® Neural tube charged compared with the outside. § The superior neuropore closes by day - Ion channels when a cell is stimulated. The diffusion of ions 27, and the inferior neuropore closes (Na+ and K+) through these channels changes the charge about 3 days later. across the plasma membrane. 2. Brain formation (Begins Day 28) - 2 phases: o When the superior neuropore closes, the future 1. DEPOLARIZATION brain region of the neural tube expands to form - The inside of the cell becomes positively charged brought three enlargements: by the inflowing positively charged sodium ions. 1. Hindbrain: helps regulate autonomic - Once threshold is reached (-65 to -55mv), an action functions, relay sensory information, potential is triggered; only 5 – 15mv is need to stimulate coordinate movement, and maintain balance action potential. and equilibrium. 2. Midbrain: helps to regulate movement and 2. REPOLARIZATION process auditory and visual information. - Rapid diffusion of potassium ions to the exterior re- 3. Forebrain: process sensory information, establishes RMP. helps with reasoning and problem – solving, - K opens, Na close = outflow of + charge ions. and regulates autonomic, endocrine, and HYPERPOLARIZATION motor functions. - Membrane potential becomes more negative and is the movement of the membrane potential further away from zero. 3 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN o Basal nuclei 1. CEREBRAL CORTEX (GRAY MATTER) - Functions: Speech, memory, logical and emotional responses, consciousness, interpretation of sensation, and voluntary movement - Primary somatic sensory area o Located in parietal lobe posterior to the central sulcus. o Allows you recognize pain, differences in temperature, or a light touch. - Homunculus o A spatial map that has been developed to show how much tissue in primary somatic sensory area is devoted to various sensory functions. - Primary motor area o Allows us to consciously move our skeletal muscles. o Axons of these motor neuron form the major voluntary motor tract – pyramidal tracts / corticospinal tract which descends to the cord. - Broca’s area o A specialized cortical area that is very involved in our ability to speak. 2. CEREBRAL WHITE MATTER - The deeper cerebral white matter composed of fiber tracts THE BRAIN carrying impulses to, from, or within the cortex (corpus - Brain is divided into four main parts: callosum) o Cerebrum: largest part, responsible for thought, memory, and voluntary movement. 3. BASAL NUCLEI o Cerebellum: controls coordination and balance, - Regulate voluntary motor activities by modifying and maintains body posture. instructions sent to skeletal muscles by primary motor o Brainstem: controls basic life functions, like cortex. breathing and heart rate (midbrain, pons, and medulla oblongata) 4 LOBES IN CEREBRAL HEMISPHERES o Diencephalon: includes the thalamus (relay - Frontal lobe: anterior; muscle movement, moods, station), and hypothalamus (regulates aggression, smell, motivation. homeostasis) - Parietal lobe: touch, pain, balance, taste, temperature. - Temporal lobe: hearing, smell, memory, abstract, thought, judgement. - Occipital lobe: posterior; vision. A. CEREBRUM - Most superior part of the brain. - Longitudinal fissure: separate two hemispheres - Gyri: folds; white portion - Sulci: grooves; spaces - Corpus callosum: bridge connecting two hemispheres. B. CEREBELLUM - Cerebrum has three basic regions: o Cerebral cortex (gray matter) - Also known as the “little brain” o Cerebral white matter - Large, cauliflower – like cerebellum. 4 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN - Also has an outer cortex (made up of gray matter) and inner 4. RETICULAR FORMATION region (white matter). - Diffuse system consisting several loosely packed nuclei - It communicates with other regions of the CNS through scattered throughout the length of the brainstem. three large tracts: superior, middle, and cerebellar - Controls consciousness, including the sleep – wake cycle peduncles. (Reticular Activating System, RAS) - Function: coordinating muscle movements, maintaining - Coordinates the rhythmic activities of swallowing, posture and balance. breathing, and the heart rate. - If damaged, can cause comatose. C. BRAINSTEM D. DIENCEPHALON - Connects the spinal cord to the remainder of the brain. - Part of the brain between the brainstem and the cerebrum. - Responsible for many essential functions. - Its main components are: - Pathway for ascending and descending nerve tracts. o Thalamus - The brainstem consists of three parts: o Hypothalamus o Medulla Oblongata – lowest o Epithalamus o Pons o Midbrain – highest 1. MEDULLA OBLONGATA - Most inferior part of the brainstem and is continuous inferiorly with the spinal cord. - Some tracts cross over in medulla. It serves as a conduit for ascending and descending nerve fibers. - Reflex centers: regulating heart rate, blood vessel diameter, respiration, swallowing, vomiting, hiccupping, coughing, and sneezing. 1. THALAMUS - Nuclei of cranial nerves: - Largest part of diencephalon, constituting about four – fifths o Extensions only: V (trigeminal), VII (facial) of its weight. o Major: IX (glossopharyngeal), X (vagus), XI - Relay station for sensory impulses except olfactory (accessory), XII (hypoglossal) o All sensation: vision, auditory, tactile, touch - Interpretation center for pain, temperature, and touch. 2. PONS 2. HYPOTHALAMUS - Superior to medulla oblongata. - The most inferior portion of diencephalon. - Pontine nuclei: relay information from the cerebrum to the - Mammillary bodies: on the ventral surface of the cerebellum. diencephalon - Initiates rapid eye movement sleep. o Olfactory reflexes - Help control respiratory movements. o Emotional responses to odors. - Nuclei for cranial nerves: - “Central controller of the endocrine system” o V (trigeminal), VI (abducens), VII (facial), VIII - Functions: Circadian rhythm, Appetite, Thermoregulation, (vestibulocochlear) Emotion, Endocrine, Sexual drive. 3. MIDBRAIN - Limbic system or emotional visceral brain: center for - Smallest region of the brainstem. many drives and emotions. - Serves as reflex center because it connects the functions 3. EPITHALAMUS of the eyeball, ears, and trunks. - It forms the roof of the third ventricle. o Control movement of the head and eyeball (visual - Important parts: pineal gland and choroid plexus. stimuli) o Control movement of head and trunk (auditory THE SPINAL CORD stimuli) - Long, cylindrical structure made of nervous tissue. - Part of auditory pathway. - Extend from the brainstem down the vertebral column. - Involved in maintaining muscle tone and coordinating - A two – way conduction pathway to and from the brain. movements. - Major reflex center. - Nuclei of cranial nerves: - Cushioned and protected by meninges. o Major: III (oculomotor), IV (trochlear) o Extension V (trigeminal) - From the foramen magnum to the level of the second lumbar vertebra (L2) 5 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN o Found in the lower border of L1 in adults (upper PERIPHERAL NERVOUS SYSTEM boarder of L3 in children) - Consists of nerves and scattered ganglia (groups of - Large in diameter at its superior end, and it gradually neuronal cell bodies found outside the CNS). decreases in diameter toward its inferior end. - 2 division: - Give rise to 31 pairs of spinal nerves, which exit the o Somatic Nervous System: Voluntary (Cranial vertebral column. and Spinal nerves) - Composed of cervical (8 pairs, C1 – C8), thoracic (12 o Autonomic Nervous System: Involuntary pairs, T1 – T12), lumbar (5 pairs, L1 – L5), sacral (5 pairs, (Sympathetic and Parasympathetic) S1 – S5), and coccygeal (1 pair, Co1). SOMATIC NERVOUS SYSTEM - 2 enlargements: - Controls voluntary movements. o Cervical enlargement - Composed of: o Lumbosacral enlargement o Cranial nerves - Conus medullaris: a cone – like region with its tip as the o Spinal nerves inferior end of the spinal cord and extends to the level of the A. CRANIAL NERVES second lumbar vertebra. - 12 pairs of cranial nerves primarily serve the head and - Cauda equina: the numerous roots of spinal nerves neck. extending inferiorly resemble a horse’s tail. - Only one pair (the vagus nerves) extends to the thoracic - Filum terminale – extension of pia matter. and abdominal cavities. - Spinal nerves connect at roots - Three pairs – the optic, olfactory, and vestibulocochlear o Dorsal root: sensory nerves are purely sensory in function. o Ventral root: motor - Each dorsal root contains a ganglion, called the dorsal root Olfactory (Sensory) Smell ganglion or spinal ganglion. Optic (Sensory) Visual acuity o These are collections of cell bodies of the sensory Oculomotor (Motor) Eye movement, pupil dilation neurons forming the dorsal roots of the spinal nerves. Trochlear (Motor) Vertical eye movement THE MENINGES Trigeminal (Both) S: Facial sensation - It is three connective tissue membranes that covers and M: Facial expression protects the CNS structures. Abducens (Motor) Lateral movement of eyeballs - Dura matter Facial (Both) S: Taste o Outermost layer, meaning “tough or hard mother”. M: Facial expression o Double – layer membrane where it surrounds the Vestibulocochlear (Sensory) Hearing and balance brain. Glossopharyngeal (Both) S: Taste o Meningeal layer: forms the outermost covering of M: Swallowing the brain and continues as the dura mater of the Vagus (Both) S: Sensation in throat and spinal cord. visceral muscles - Arachnoid matter M: Vocal cords, peristalsis o Middle meningeal layer, meaning “spider” Accessory (Motor) Head and shoulder movement o Looks like a cobweb. Hypoglossal (Motor) Tongue movement - Pia matter o Innermost membrane, meaning “gentle mother” B. SPINAL NERVES o Clings tightly to the surface of the brain and spinal cord, following every fold. - 31 pairs of human spinal nerves are formed by the combination of ventral and dorsal roots of the spinal cord. THE CEREBROSPINAL FLUID - Contain axons of sensory and somatic motor neurons. - Watery “broth” with components similar to blood plasma. - Located between vertebra. - Contains less protein and more vitamin C. REFLEX ARC - The choroid plexuses – clusters of capillaries hanging from the “roof” in each of the brain’s ventricles, or enlarged - Basic functional unit of the nervous system. chambers – continually form CSF from blood. - Smallest, simplest portion capable of receiving stimulus and - It forms a water cushion that protects the fragile nervous producing a response. tissue from blows and other trauma. REFLEX - Helps the brain “float” so it is not damaged by the pressure - Automatic response to a stimulus produced by a reflex arc. of its own weight. - It means it occurs without conscious thought. - Three major spinal cord reflexes: o Stretch reflex o Golgi tendon reflex 6 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN o Withdrawal reflex. AUTONOMIC NERVOUS SYSTEM 1. STRECH REFLEX - It controls body activities automatically. - Simplest reflex. - Composed of specialized group of neurons that regulate - Occurs when muscles contract in response to a stretching cardiac muscle (the heart), smooth muscles (found in the force. walls of the visceral organs and blood vessels), and glands. - Knee – jerk reflex / patellar reflex - Autonomic functioning: o When a clinician taps the patellar ligament. o Body organs served by the autonomic nervous o Muscle spindle: sensory receptor of this reflex. system receive fibers from both divisions. 2. GOLGI TENDON REFLEX o Exceptions: blood vessels and most structures of - It prevents contracting muscles from applying excessive the skin, some glands, and the adrenal medulla tension to tendons. (all of which receive only sympathetic fibers). o The parasympathetic fibers, called cholinergic - Have a high threshold and are sensitive only to intense fibers, release acetylcholine. stretch. o The sympathetic postganglionic fibers, called 3. WITHDRAWAL REFLEX / FLEXOR REFLEX adrenergic fibers, release norepinephrine. - It is to remove a limb or another body part from a painful A. SYMPATHETIC DIVISION stimulus. - Referred to as the “fight or flight response” - Crossed extensor reflex o Occurs on the opposite side of the body from the - Dilates pupils, inhibits salivation, relaxes bronchi, accelerates heartbeat, inhibit peristalsis, and secretion, stimulus. stimulates glucose production, secretion of adrenaline and A. CERVICAL PLEXUS noradrenaline, inhibits bladder contraction, stimulates - Small plexus originating from spinal nerves C1 – C4 with orgasm. the contributions from C5. B. PARASYMPATHETIC DIVISION - Supplies the skin and muscles of the head, neck, and - Referred to as the “rest and digest” superior part of the shoulders and chest. - Most active when the body is at rest and not threatened in - Phrenic nerves: arise from the cervical plexus and supply any way. motor fibers to the diaphragm. - Constricts pupils, stimulates saliva flow, constricts bronchi, B. BRACHIAL PLEXUS slows heartbeat, stimulates peristalsis and secretion, - It forms from the roots of spinal nerves C5 – C8 and T1. stimulates bile release, contracts bladder. - Provides almost the entire nerve supply of the shoulders NEUROTRANSMITTERS and upper limbs. - Any specific chemical agents released by a presynaptic cell - Five large terminal branches: on excitation that cross the synaptic cleft and stimulate or o Axillary nerve: supplies the deltoid and teres inhibit the postsynaptic cell. minor muscles. - Neurotransmitters may affect the post synaptic neuron o Musculocutaneous: supplies the anterior directly, by activating ion channels (ionotropic), or muscles of the arm. indirectly by activating proteins inside the postsynaptic o Radial nerve: supplies the muscles on the neuron (metabotropic). posterior aspect of the arm and forearm. - Cholinergic neurons releases acetylcholine. o Median nerve: supplies most of the muscle of anterior forearm and some muscles of the hand. - Adrenergic neurons release norepinephrine. o Ulnar nerve: supplies anteromedial muscles of the forearm and most of the muscles of the hand. Adrenaline (fight or flight) Produced in stressful C. LUMBAR PLEXUS situations. Increases heart rate and blood flow, leading to - It forms from the roots of spinal nerves L1 – L4. physical boost and heightened - Femoral nerve: supplies the anterior and lateral thigh and awareness. the medial leg and foot. Noradrenaline / Affects attention and - Obturator nerve: supplies the medial side of the thigh. Norepinephrine responding to actions in the - Sciatic nerve: largest nerve in the body; splits to common (concentration) brain. Contracts blood vessels, fibular and tibial nerve. increasing blood flow. D. SACRAL PLEXUS Undersupply is linked to - It forms from the roots of spinal nerves L4 – L5 and S1 – Depressed Mood S4. Dopamine (pleasure) Feelings of pleasure. Also - Situated largely anterior to the sacrum. addiction. Movement and - Supplies the buttocks, perineum, and lower limbs. motivation. People repeat behaviors that lead to dopamine release. 7 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN Oversupply is linked to TYPES OF BRAIN HEMORRHAGE Schizophrenia; Undersupply 1. Epidural hematoma: collection of blood that forms is linked to Tremors. between your skull and the dura matter (outermost Serotonin (mood) Contributes to well – being and protective membrane) happiness. Helps sleep cycle 2. Subdural hematoma: bleeding inside your head and blood and digestive system collects under the dura matter. regulation. Affected by 3. Subarachnoid hemorrhage: bleeding in the space below exercise and light exposure. one of the thin layers that cover and protect your brain. 4. Intracerebral hemorrhage: bleeding in the brain caused Deficiency is linked to by the rupture of a damaged blood vessel in the head. Depression GABA (calming) Calms firing nerves in the TYPES OF NERVE INJURIES CNS. High levels improve focus, low levels cause 1. Stretch nerve injury anxiety. Also contributes to 2. Rupture nerve injury motor control and vision. 3. Avulsion injury Undersupply is linked to Seizure and Insomnia NEUROLOGY Acetylcholine (learning) Involved in thought, learning - A branch of medicine dealing with disorders of the nervous and memory. Activates muscle system. action in the body. Also, - A neurologist is a physician specializing in neurology and associated with attention and trained to investigate, or diagnose and treat neurological awakening. disorders. Deficiency causes Alzheimer - Signs and symptoms of neurological disorders: Glutamate (memory) Most common o Partial or complete paralysis neurotransmitter. Involved in o Muscle weakness learning and memory. o Partial or complete loss of sensation Regulates development and o Seizures creation of nerve contacts. o Difficulty reading and writing o Poor cognitive abilities Oversupply causes o Unexplained pain Restlessness; Undersupply o Decreased alertness hinders concentration. Endorphins (euphoria) Released during exercise, MOST COMMON NEUROLOGICAL DISORDERS excitement, and sex. EPILEPSY Producing well – being and euphoria, reducing pain. - Seizures involving a sudden, massive neuronal discharge, which may result in involuntary muscle contractions Undersupply is linked to (convulsions). Depression, Anxiety and ALZHEIMER DISEASE Chronic Headache. - Dementia; usually affects older people. - Involves loss of neurons in the cerebral cortex; symptoms include general intellectual deficiency, memory loss, short EFFECTS OF AGING ON THE BRAIN attention span, moodiness, disorientation, and irritability - Decrease in brain weight and volume. CEREBROVASCULAR DISEASES - Decrease in white matter. - Involved the death of brain tissue due to disruption of its - Ventricular system enlarges. vascular supply. - Brain generates fewer neurotransmitters. MIGRANE - After age 60, the brain begins to lose thousands of neurons - It usually occurs on only one side of the head and appear a day. When these cells die, they are not replaced. to involve a combination of neurological dysfunction and - By age 80, the brain weighs about 10% less than it did when abnormal dilation and constriction of blood vessels. the person was a younger adult. MULTIPLE SCLEROSIS - The cerebral cortex shrinks more than any other area. - Autoimmune condition; may be initiated by viral infection; Therefore, mental activities such as learning, memory, and inflammation in brain and spinal cord with demyelination reasoning decline. and sclerotic (hard) sheaths result in poor conduction of action potentials. - Neurotransmitter production also decreases, resulting in slower synaptic transmission, slowing down thought - Symptoms include exaggerated reflexes, tremor, and processing, and translation of a thought into action. speech defects. 8 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER  ANATOMY AND PHYSIOLOGY MC2 | MS. DEMYBHELLE VISAYA, RN NEUROLOGICAL DISORDER - A transient ischemic attack (TIA) PARKINSON’S DISEASE o is an episode of temporary cerebral dysfunction - Characterized by muscular rigidity; loss of facial caused by impaired blood flow to part of the brain. expression; tremor; a slow, shuffling gait; and general lack - Attention deficit hyperactivity disorder (ADHD) of movement. o is a learning disorder characterized by poor or NEUROINFECTIONS short attention span, a consistent level of - Shingles hyperactivity, and a level of impulsiveness o is an acute infection of the peripheral nervous inappropriate for the child’s age. system caused by herpes zoster, the virus that ANENCEPHALY also causes chickenpox. - The cranial bones fail to develop and certain parts of the - Poliomyelitis or simply polio brain remain in contact with amniotic fluid and degenerate. o is caused by a virus called poliovirus. The onset of SPINA BIFIDA the disease is marked by fever, severe headache, - A congenital defect of the vertebral column in which laminae a stiff neck and back, deep muscle pain and weak- of L5 and/or S1 fail to develop normally and unite at the ness, and loss of certain somatic reflexes. midline. - Post-polio syndrome. - Least form: spina bifida occulta. o This neurological disorder is characterized by progressive muscle weakness, extreme fatigue, loss of function, and pain, especially in muscles and joints. - Meningitis o Inflammation of the meninges due to an infection, usually caused by a bacterium or virus. - Myelitis o Inflammation of the spinal cord. BRAIN TUMORS - An abnormal growth of tissue in the brain that may be malignant or benign. - Malignant and benign brain tumors may be equally serious, compressing adjacent tissues and causing a buildup of pressure in the skull. - The most common malignant tumors are secondary tumors that metastasize from other cancers in the body TRAUMATIC DISORDERS - Most spinal cord injuries are due to trauma as a result of factors such as automobile accidents, falls, contact sports, diving, and acts of violence. - Depending on the location and extent of spinal cord damage, paralysis may occur. o Monoplegia is paralysis of one limb only. o Diplegia is paralysis of both upper limbs or both lower limbs. o Paraplegia is paralysis of both lower limbs. o Hemiplegia is paralysis of the upper limb, trunk, and lower limb on one side of the body. o Quadriplegia is paralysis of all four limbs. - Complete transection of the spinal cord means that the cord is severed from one side to the other, thus cutting all sensory and motor tracts. - Hemi section is a partial transection of the cord on either the right or the left side. - Following complete transection, and to varying degrees after hemi section, spinal shock occurs. o Spinal shock is an immediate response to spinal cord injury characterized by temporary areflexia; loss of reflex function. 9 MINA A.Y. 2024 - 2025 BSN1-AB FIRST SEMESTER