Chapter 9 Nervous System https://www.youtube.com/watch?v=qPix_X-9t7E

The Nervous System Central Nervous System Brain Spinal Cord Peripheral Nervous System Cranial Nerves Spinal Nerves Autonomic Nervous System Sympathetic Nerves Parasympathetic Nerves

Introduction Nervous system: Complex: 10 billion nerve cells Voluntary and involuntary functions Nerves carry electrical messages External and internal receptors What are external stimuli? How can internal chemicals be stimuli? What are some of the involuntary body functions controlled by the nervous system?

Nervous System Two major divisions: Central nervous system Brain Spinal cord Peripheral nervous system cranial nerves: Cranial nerves carry electrical impulses between the brain and the head and neck (except vagus nerve). spinal nerves: Spinal nerves carry impulses between the spinal cord and the chest, abdomen, and extremities. Cranial nerves carry electrical impulses between the brain and the head and neck (except vagus nerve). Spinal nerves carry impulses between the spinal cord and the chest, abdomen, and extremities. Why is the 10th cranial nerve called the vagus nerve? What does it do?

Vagus Nerve

General Structure of the Nervous System Cranial and spinal nerves Sensory nerves carry messages toward the brain. Motor nerves carry messages from the brain. Mixed nerves carry both sensory and motor fibers. Sensory receptors What is the difference between voluntary and involuntary functioning? What are parasympathetic and sympathetic nerves?

General Structure of the Nervous System (cont’d.) Autonomic nervous system: Carries impulses from the central nervous system to organs. The autonomic nervous system contains a large group of nerves that function automatically. It controls heart, blood vessels, glands, and involuntary muscles like intestines, and hollow organs such as stomach and urinary bladder. Why is the autonomic nervous system necessary?

Automomic Nervous System Sympathetic nerves stimulate body under stress. Parasympathetic nerves balance sympathetic system. Slow heart rate Lower blood pressure

Divisions of the Central and Peripheral Nervous System How are stimuli processed by the nervous system? What are the parenchymal cells of the nervous system?

Neurons, Nerves, and Glia Neuron = individual nerve cell Dendrite – branching fibers of neuron Cell nucleus What structure carries the nerve impulse away from the cell body? What substances are examples of neurotransmitters? What is the singular form of “ganglia”?

Neurons, Nerves, and Glia Axon – carry impulses away Myelin sheath – fatty tissue that covers the axon giving it a white color (white matter) Gray Matter – cell bodies of neurons not covered with a myelin sheath.

Neurons, Nerves, and Glia Synapse – space where nervous impulse jumps from one neuron to another Terminal end fibers - (secrete neurotransmitters) Neurotransmitters - transfer impulse across synapse Ganglia - small clusters of nerve cell bodies outside the brain and spinal cord.

Neurotransmitters – chemicals that control the transfer of an impulse across the synapse Acetylcholine Norepinephrine Epinephrine Dopamine Serotonin Endorphins

What are the parts of the neurons shown in this slide? What structures comprise the parenchymal cells of the nervous system?

The Brain– Controls body activities, weighs about 3 lbs The brain is divided into right and left hemispheres. The brain consists of four major lobes, including the frontal lobe, parietal lobe, temporal lobe, and occipital lobe. What are the parts of the left cerebral hemisphere as shown in the diagram? What primary functions are carried out by the different lobes of the brain?

The Brain The brain is divided into right and left hemispheres. The brain consists of four major lobes, including the frontal lobe, parietal lobe, temporal lobe, and occipital lobe.

The Cerebrum Largest section of brain Surface has nerve cells called cerebral cortex. Manages speech, vision, smell, movement, hearing, and thought What is the purpose of the cerebral cortex? How many major divisions can be applied to the entire cerebral cortex?

Cerebral Cortex the outer layer of the cerebrum (the cerebral cortex ), composed of folded gray matter and playing an important role in consciousness

Cerebrum Spaces in the middle of the cerebrum are called ventricles. Ventricles contain cerebrospinal fluid (CSF). This fluid cushions the brain. CSF can be removed for testing or relief of pressure on the brain.

The Brain

The Brain Cerebellum Coordinates voluntary movements Maintains balance What is the value of the ability to sense pain?

The Brain Thalamus Integrates and monitors impulses from skin (pain)

Hypothalamus Controls body temperature, sleep, appetite, sexual desire, and emotions Regulates release of hormones from pituitary gland Monitors sympathetic and parasympathetic nervous systems How do messages travel from one side of the brain to another?

The Brain The Brainstem Pons Bridges cerebrum and cerebellum with rest of the brain Houses nerves for face and eyes

The Brainstem Medulla oblongata Connects spinal cord to brain Nerve tracts from side to side Regulates: Blood vessels Heart Respiratory system How does the word “crossover” apply to a function of the medulla oblongata?

Pons and Medulla

Thyroid Gland

The Spinal Cord and Meninges The spinal cord is the column of nervous tissue from the medulla oblongata to second lumbar vertebra. It serves as a pathway for impulses to and from the brain. The inner section of the cross-section of the spinal cord is gray matter. The outer section of the cross-section of the spinal cord is white matter. What is the difference between efferent and afferent neurons?

The spinal cord is the column of nervous tissue from the medulla oblongata to second lumbar vertebra. It serves as a pathway for impulses to and from the brain. The inner section of the cross-section of the spinal cord is gray matter. The outer section of the cross-section of the spinal cord is white matter. What is the difference between efferent and afferent neurons?

Meninges Meninges Meninges are the three layers of connective tissue membranes that surround the brain and spinal cord. What is the function of the outer dura mater? (channels blood to brain tissue) What fluid lies between the arachnoid membrane and the subarachnoid space? The inner pia mater offers a rich supply of blood vessels. Where are the layers of the meninges in the figure?

Meninges are the three layers of connective tissue membranes that surround the brain and spinal cord. What is the function of the outer dura mater? (channels blood to brain tissue) What fluid lies between the arachnoid membrane and the subarachnoid space? The inner pia mater offers a rich supply of blood vessels.

Meningitis

Combining Forms – p. 419 Cephal/o head Cerebr/o cerebrum dur/o dura mater Encephal/o brain Gli/o glia (nervous tissue)

Combining Forms – p. 419 Mening/o meninges Meningi/o Myel/o spinal cord Neur/o nerve

Combining Forms Deep sleep Feeling, nervous sensation (anesthesia without this feeling) movement comat/o esthesi/o, esthesi/a kines/o, -kinesia

Suffixes -paresis partial paralysis - hemiparesis -phasia speech -plegia paralysis - quadraplegia

Suffixes -asthenia weakness alges/o, algesia sensitivity to pain Algia pain

QUICK QUIZ: 3. Which term means nerve pain? A. cephalgia B. analgesia C. hypalgesia D. neuralgia CORRECT Answer is D, neuralgia

Pathologic Conditions Hydrocephalus – abnormal accumulation of fluid in the brain Spina bifida Spina bifida cystica Spina bifida occulta How is hydrocephalus treated? What are the two types of spina bifida? Ask students to describe the differences between the two types.

Spina Bifida Spina bifida occulta is the most common and least severe spinal cord defect. Incomplete closure of one or more vertebrae without protrusion of spinal cord or meninges. Spinal cord is covered with a layer of skin.

Spina Bifida Spina bifida cystica has two classifications: Meningocele—sac contains only meninges and cerebrospinal fluid (CSF). Meningomyelocele―sac contains meninges, CSF, and a portion of the spinal cord.

Meningomyelocele

Degenerative, Movement, and Seizure Disorders Multiple sclerosis (MS) Myasthenia gravis (MG) Palsy Parkinson disease Tourette syndrome Alzheimer disease (AD) Amyotrophic lateral sclerosis (ALS) Epilepsy Huntington disease Which conditions are movement related? Which conditions are degenerative?

Bell Palsy

Infectious Disorders Herpes zoster (shingles) Meningitis Human immunodeficiency virus (HIV) encephalopathy What is a viral infection caused by chickenpox? What types of meningitis exist, and how is meningitis treated? What is the most malignant form of brain tumor?

Shingles, also known as zoster or herpes zoster, is a painful skin rash caused by the same virus responsible for chicken pox: the varicella zoster virus. Even if you hadchicken pox in the past, you can still contract shingles

Brain Tumor Glioblastoma multiforme (GBM) is the most common and deadliest of malignantprimary brain tumors in adults and is one of a group of tumors referred to as gliomas. Classified as a Grade IV (most serious) astrocytoma, GBM develops from the lineage of star-shaped glial cells, called astrocytes, that support nerve cells.

Neoplastic Disorders

Traumatic Disorders Cerebral concussion: Temporary brain dysfunction after injury, usually clears within 24 hours What is the primary difference between a concussion and a contusion?

Cerebral Contusion Bruising of brain tissue through direct trauma to head Neurological deficits persist longer than 24 hours

CVA cerebral vascular accident – Thrombotic — blood clot in artery leaving to the brain Embolic — dislodged clot that travels to cerebral arteries Hemorrhagic — a blood vessel, such as the cerebral artery breaks, and bleeding occurs What is the primary difference between a concussion and a contusion?

Vascular Disorders There are three types of cerebrovascular accident (CVA): thrombotic, embolic, and hemorrhagic. What is another name for CVA? What causes a transient ischemic attack (TIA)?

TIA

Clinical Procedures Cerebral angiography X-ray Tests Cerebral angiography Computed tomography (CT) of the brain Myelography Which x-ray uses a contrast medium?

Clinical Procedures MRI - Magnetic resonance Imaging MRA - Magnetic resonance angiogram PET - Positron emission scan EEG - Electroencephalography

Lumbar Puncture (LP) A needle is inserted in the spinal cord for removal of CSF.

MRA and MRI

MRI

CT Scan

PET scan reveals the cellular level metabolic changes occurring in an organ or tissue.

PET Scan - Positron Emission Tomography The red color shows the highest level of glucose utilization, yellow represents less utilization and blue shows the least.

Abbreviations page 429 AD ALS Alzheimer disease amyotrophic lateral sclerosis Which items are disorders or injuries, and which are procedures?

Abbreviations – page 429 CNS central nervous system CT computed tomography CVA cerebrovascular accident CSF cerebrospinal fluid

Abbreviations EEG ICP LP Electroencephalogram intracranial pressure lumbar puncture Which items are pathologies, and which are tests? What is an EEG used to measure?

Abbreviations myasthenia gravis MG magnetic resonance angiography MRA magnetic resonance imaging MG MRA MRI

Build Medical Terms pertaining to the cerebrum and spine: incision of the cranium (skull): crushing a nerve: hernia(tion) of meninges and spinal cord:

Build Medical Terms pertaining to the cerebrum and spine: cerebrospinal incision of the cranium (skull): craniotomy crushing a nerve: neurotripsy hernia(tion) of meninges and spinal cord: meningomyelocele

Build Medical Terms inflammation of gray matter of spinal cord: paralysis of four (limbs): tumor of nerve, embryonic cell:

Build Medical Terms inflammation of gray matter of spinal cord: poliomyelitis paralysis of four (limbs): quadriplegia tumor of nerve, embryonic cell: neuroblastoma

Build Medical Terms pertaining to the cerebrum: condition of water in the head: separation, destruction, or loosening of a nerve:

Build Medical Terms pertaining to the cerebrum: cerebral condition of water in the head: hydrocephalus separation, destruction, or loosening of a nerve: neurolysis

Craniotomy Incision of the skull to gain access to the brain during neurological procedures. Performed to control brain bleeds, relieve intracranial pressure (ICP), and remove brain tumors.

Pharmacology Anesthetics Produce partial or complete loss of sensation, with or without loss of consciousness. General anesthetics act on brain to produce complete loss of consciousness. Local anesthetics act on nerves or nerve tracts to affect a local area only.

Pharmacology Anticonvulsants Antiparkinsonian agents Prevent or reduce severity of epileptic or other convulsive seizures; also called antiepileptics. Antiparkinsonian agents Control tremors and muscle rigidity associated with Parkinson disease by increasing dopamine levels in the brain.

Pharmacology Antipsychotics Alter neurotransmitters in the brain to alleviate symptoms of psychosis, paranoia, and schizophrenia.