Nervous System General Structure Central Nervous System CNS

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Nervous System

Nervous System

General Structure • Central Nervous System (CNS) • Brain & spinal cord • Peripheral

General Structure • Central Nervous System (CNS) • Brain & spinal cord • Peripheral Nervous System (PNS) • Cranial nerves • Carry impulses between the brain & the head & neck • Exception: Vagus Nerve • Spinal nerves • Plexus = large network of nerves • Peripheral nerves

Peripheral Nervous System • Spinal & Cranial nerves are composed of: • Sense receptors

Peripheral Nervous System • Spinal & Cranial nerves are composed of: • Sense receptors • For sight, hearing, balance, smell, touch & Sensory (afferent) nerves • Carry messages toward the spinal cord & brain • Motor (efferent) nerves • Travel from the spinal cord & brain to muscles, telling them how to respond

Peripheral Nervous System • Autonomic nervous system • Function involuntarily or automatically • Carries

Peripheral Nervous System • Autonomic nervous system • Function involuntarily or automatically • Carries impulses away from the CNS to the glands, heart, blood vessels, & involuntary muscles (intestines, stomach, bladder) • Autonomic nerves • Sympathetic nerves • Stimulate the body in times of stress & crisis • Increase heart rate, dilate airways, increase BP, stimulate the adrenal glands, inhibit intestinal contractions • Parasympathetic nerves • Slow down heart rate, lower BP & stimulate intestinal contractions

Neurons, Nerves, & Glial Cells • Neuron • Individual nerve cell • Ganglia •

Neurons, Nerves, & Glial Cells • Neuron • Individual nerve cell • Ganglia • Small collections of nerve cell bodies outside the brain & spinal cord

Synapse • Space where the nervous impulse jumps from one neuron to the other.

Synapse • Space where the nervous impulse jumps from one neuron to the other. • Neurotransmitter • Chemical substance that transfers the impulse • Acetylcholine, norepinephrine, dopamine, serotonin, endorphins

Nerve • Consists of a bundle of dendrites and axons that travel together like

Nerve • Consists of a bundle of dendrites and axons that travel together like strands of rope • Peripheral nerves • Carry impulses to the brain (afferent or sensory nerves) • Carry impulses from the CNS to organs (efferent or motor nerves)

Glial Cells (Neuroglial Cells) • Supportive, protective, and connective tissue of the CNS •

Glial Cells (Neuroglial Cells) • Supportive, protective, and connective tissue of the CNS • Glial cells are stromal (framework) tissue, whereas neurons carry nervous impulses 1. Astrocytes • • Star-like apperance (astr/o = star) Transports water & salts between capillaries & neurons 2. Microglial cells • Protect neurons in response to inflammation 3. Oligodendrocytes • • Few dendrites (olig/o = few or scanty) Form the myelin sheath in the CNS 4. Ependymal cells • Line membranes where cerbrospinal fluid (CSF) circulates

The Brain • Cerebrum • Largest part of the brain. • Cerebral cortex •

The Brain • Cerebrum • Largest part of the brain. • Cerebral cortex • Nerve cells lie in sheets on the surface of the cerebrum • Gyri – folds in the sheets • Sulci – grooves that separate the gyri • Cerebral Hemispheres • Divides the brain in right & left sides. Each divided into lobes • Frontal • Thought processes, behavior, personality, emotion • Parietal • Body sensations, visual & spatial perception • Occipital • vision • Temporal • Hearing, understanding, speech, language

The Brain • Thalamus • Acts like a triage center. Decides what is important

The Brain • Thalamus • Acts like a triage center. Decides what is important & what is not. • Hypothalamus • Contain neurons that control temperature, sleep, appetite, emotions (fear & pleasure). Regulates hormones from the pituitary gland

The Brainstem • Lie in the back & below the cerebrum & connect the

The Brainstem • Lie in the back & below the cerebrum & connect the brain to the spinal cord • Cerebellum • Functions to coordinate voluntary movements & maintain balance & posture • Pons • Literally means bridge. Connects the cerebellum & cerebrum with the rest of the brain • Medulla oblongata • Connects the spinal cord with the rest of the brain • Regulates: • Respiratory center: controls muscles of respiration • Cardiac center: slows the heart rate if beats are too rapid • Vasomotor center: constricts or dilates the blood vessels, influencing blood pressure

The Spinal Cord & Meninges • Column of nervous tissue from the medulla oblongata

The Spinal Cord & Meninges • Column of nervous tissue from the medulla oblongata to L-2. • Cauda Equina (Latin for “horse’s tail) is a fan of nerve fibers below the end of the spinal cord.

Spinal Cord • Cross-Sectional View • Gray matter • Containing cell bodies & dendrites

Spinal Cord • Cross-Sectional View • Gray matter • Containing cell bodies & dendrites • White matter • Containing the nerve fiber tracts with myelin sheaths

Meninges • Three layers of connective tissue that surround the brain & spinal cord

Meninges • Three layers of connective tissue that surround the brain & spinal cord • dura mater • epidural • subdural • arachnoid • subarachnoid space • contains CSF • pia mater • blood vessels and lymph

Pathology • Maybe classified in the following categories • Congenital • Neoplastic (tumors) •

Pathology • Maybe classified in the following categories • Congenital • Neoplastic (tumors) • Degenerative, movement, & seizure • Traumatic • Infectious (meningitis & encephalitis) • Vascular (stroke)

Congenital Disorders • Hydrocephalus • Abnormal accumulation of fluid (CSF) in the brain •

Congenital Disorders • Hydrocephalus • Abnormal accumulation of fluid (CSF) in the brain • Spina bifida • Congenital defects in the lumbar spinal column caused by imperfect union of vertebral parts (neural tube defect) • Spina bifida occulta • Vertebral defect is covered over & only evident on x-ray • Meningocele • Meniges protrudes to the outside • Myelomeningocele • Both spinal cord & meninges protrude

Degenerative, Movement, & Seizure Disorders • Alzheimer disease (AD) • Brain disorder marked by

Degenerative, Movement, & Seizure Disorders • Alzheimer disease (AD) • Brain disorder marked by gradual & progressive mental deterioration, personality changes, & impairment of daily living • Epilepsy • Chronic brain disorder characterized by recurrent seizure activity • Huntington disease • Hereditary disorder marked by degenerative changes in the cerebrum leading to abrupt involuntary movements & mental deterioration. • Multiple Sclerosis (MS) • Destruction of the myelin sheath on neurons in the CNS & its replacement by plaques of sclerotic (hard) tissue

Infectious Disorders • Herpes Zoster (shingles) • Viral infection affecting peripheral nerves • Meningitis

Infectious Disorders • Herpes Zoster (shingles) • Viral infection affecting peripheral nerves • Meningitis • Inflammation of the meninges; leptomeningitis • Human Immunodeficiency Virus Encephalopathy • Brain disease & dementia occurring with AIDS

Neoplastic Disorders • Brain Tumor • Abnormal growth of brain tissue & meninges •

Neoplastic Disorders • Brain Tumor • Abnormal growth of brain tissue & meninges • Most arise from glial cells or the meninges

Traumatic Disorders • Cerebral concussion • Temporary brain dysfunction (brief loss of consciousness) after

Traumatic Disorders • Cerebral concussion • Temporary brain dysfunction (brief loss of consciousness) after injury, usually clearing within 24 hours • Cerebral contusion • Bruising of brain tissue as a result of direct trauma to the head; neurologic deficits persist longer than 24 hours

Vascular Disorders • Cerebrovascular accident (CVA) • Disruption in the normal blood supply to

Vascular Disorders • Cerebrovascular accident (CVA) • Disruption in the normal blood supply to the brain; stroke • Thrombotic – blood clot (thrombus) in the arteries leading to the brain • Embolic – an embolus (dislodged thrombus) travels to cerebral arteries & occludes a small vessel • Hemorrhagic - blood vessel breaks

Audionyms

Audionyms

Auto • Audionym • Auto • Visual Image • See the AUTOmatic car driving

Auto • Audionym • Auto • Visual Image • See the AUTOmatic car driving ITSELF • Meaning • self

Blephar • Audionym • Blue fur • Visual image • See the lady wearing

Blephar • Audionym • Blue fur • Visual image • See the lady wearing BLUE FUR with EYELIDS • Meaning • eyelid

Cau-, caus • Audionym • Cough • Visual Image • See the COUGH the

Cau-, caus • Audionym • Cough • Visual Image • See the COUGH the BURNS • Meaning • burn

Dacry-, lacrim • Audionym • Daiquiri • Visual Image • See the DAIQUIRI drink

Dacry-, lacrim • Audionym • Daiquiri • Visual Image • See the DAIQUIRI drink crying a tear • Meaning • tear

Dur • Audionym • Door • Visual Image • See the DOOR with the

Dur • Audionym • Door • Visual Image • See the DOOR with the HARD hat on it. • Meaning • Hard, dura mater

Hemi • Audionym • Hemisphere • Visual Image • See the HEMIsphere in HALF

Hemi • Audionym • Hemisphere • Visual Image • See the HEMIsphere in HALF • Meaning • Half

Kerat • Audionym • Carrot • Visual Image • See the CARROT being used

Kerat • Audionym • Carrot • Visual Image • See the CARROT being used as HORNS • Meaning • Horny, horny tissue, cornea

Mening • Audionym • Manage • Visual Image • See the MANAGER managing MEN’S

Mening • Audionym • Manage • Visual Image • See the MANAGER managing MEN’S BRAINS • Meaning • membrane

Ment • Audionym • Mint • Visual Image • See the person picking up

Ment • Audionym • Mint • Visual Image • See the person picking up the MINT saying “MINE, MINE” • Meaning • mind

Neuro • Audionym • Nero • Visual Image • See NERO being very NERVOUS

Neuro • Audionym • Nero • Visual Image • See NERO being very NERVOUS as Rome burns • Meaning • Nerve (nervous system)

Ophthalm-, ocul • Audionym • Up thumb • Visual Image • See the UP

Ophthalm-, ocul • Audionym • Up thumb • Visual Image • See the UP THUMB (thumbs up) with an EYE on top • Meaning • eye

Phren • Audionym • Friend • Visual Image • See the people pulling on

Phren • Audionym • Friend • Visual Image • See the people pulling on the FRIEND saying, “MINE!” • Meaning • mind

Radic-, radicul • Audionym • Radish • Visual Image • See the RADISH it’s

Radic-, radicul • Audionym • Radish • Visual Image • See the RADISH it’s a ROOT • Meaning • Root, nerve root

Semi • Audionym • Semi colon • Visual Image • See the SEMI-colon cut

Semi • Audionym • Semi colon • Visual Image • See the SEMI-colon cut in HALF • Meaning • Half