A&P Chapter 9 Nervous System

Nerve Impulse

a self propagating wave of electrical disturbance that travels along the surface of a neurons plasma membrane; sometimes called action potentials

Autonomic Nervous System

a subdivision of peripheral nervous system that consists of structures that regulate the bodys automatic or involuntary functions

Synaptic Knob

a tiny bulge at the end of a terminal branch of a presynaptic neurons axon; contains small sacs or vesicles

Reflex Arc

allows an impulse to travel in only one direction

Multiple Neurofibromatosis

an inherited disease characterized by numerous benign fibrous neuromas throughout the body

Cell Body

main part of the neuron

Hypothalamus

maintain body's water balance, maintain body temperature and produce ADH are functions of the...

Epilepsy

many forms all chracterized by recurring seizures

Multiple Sclerosis

most common primary disease of CNS; characterized by myelin loss in central nerve fibers and results in conduction impairments

Neurons

nerve cells that conduct impulses

Nitric Oxide

neurotransmitter that diffuses directly across the plasma membrane of neurons rather than being released from vesicles; important in male sexual response

Catecholamines

norepinephrine, dopamine and serotonin are a group of compunds called...

Glioma

one of the most common types of brain tumor that develops from Glia

Hemiplegia

paralysis of one whole side of the body

Bell Palsy

paralysis of some or all of the facial features innervated by the facial nerve including eyelids and mouth

Cerebral Palsy

permanent nonprogressive damage to motor control areas of brain before, during or shortly after birth causes paralysis of one or more limbs

Dementia

progressive loss of memory, shortened attention span, personality changes, reduced intellectual capacity and motor control deficit are characteristics of this

Spinal Cord Tracts

provide two way conduction paths, ascending and descending, to and from the brain

Trigeminal Neuralgia

recurring episodes of stabbing pain along one or more branches of the fifth cranial nerve in the head

Acetylcholine

released at some of the synapses in the spinal cord and at neuromuscular junctions

Arachnoid Mater

resembles cobweb with fluid in its spaces; the membrane between the dura mater and pia mater

Cerebellum

second largest part of brain; helps muscle contractions so we can maintain balance, move smootly and sustain normal posture

Sympathetic Nervous System

serves as emergency or stress system controlling visceral effectors during strenuous exercise and with strong emotions; fight or flight response

Two Neuron Arc

simplest of reflex arcs consisting of sensory neurons and motor neurons

Dermatomes

skin surface areas that are supplied by a single spinal nerve are called...

Diencephalon

small but important part of brain located between midbrain below and cerebrum above; consists of hypothalamus and thalamus

Microglia

small cells that move in inflamed brain tissue carrying on phagocytosis

Astrocytes

star shaped cells; their threadlike branches attach to neurons and small blood vessels holding these structures close to each other

Seizure

sudden burst of abnormal neuron activity that results in temporary changes in brain function

Glia

support cells that support neurons; bringing the cells of nervous tissue together structurally and functionally

Perineurium

surrounds a group (fascicle) of nerve fibers

Endoneurium

surrounds individual fibers within a nerve

Epineurium

surrounds the whole nerve

Synapse

synaptic knob. synaptic cleft and plasma membrane makes up what...

Parasympathetic Preganglionic Neurons

terminate in parasympathetic ganglia located in head, throacic and abdominal cavities close to visceral effectors; synapses with postganglionic neurons to only one effector

Receptors

the beginnings of dendrites of sensory neurons; located some distance from spinal cord in tendons, skin and mucous membranes

Central Nervous System

the brain and spinal cord make up the...

Pia Mater

the innermost membrane covering the spinal cord itself

Peripheral Nervous System

the nerves connecting the brain and spinal cord to other parts of the body

Neurilemma

the outer cell membrane of a Schwann cell

Synapse

the place where impulses are transmitted from one neuron called the presynaptic neuron to another neuron called the postsynaptic neuron

Skeletal

the somatic nervous system carries impulses to which muscles

Synaptic Cleft

the space between a synaptic knob and the plasma membrane of a postsynaptic neuron

Astrocytes, Microglia and Oligodendrocytes

the three main types of connective tissue cells (Glia) of the CNS are called...

Neurons and Glia

the two types of cells found in the nervous system are called...

Endorphins and Enkephalins

these are released at various spinal cord and brain synapses in the pain conduction pathway; natural pain killers

Cerebral Cortex

thin layer of gray matter made up of neuron dendrites and cell bodies that makes up the surface of the cerebrum

Gray Matter

tissue in the CNS made up of cell bodies and unmyelinated axons and dendrites

Visceral Effectors

tissues to which autonomic neurons conduct impulses (i.e. cardiac muscle, smooth muscle and glandualr epithelial tissue)

Dura Mater

tough outer layer that lines the vertebral canal

Three Neuron Arc

type of reflex arc consisting of sensory neurons, interneurons and motor neurons

Herpes Zoster

viral infection caused by chickenpox virus that has invaded the dorsal root ganglion and remained dormant until an episode of shingles; affect a single dermatome

Medulla Oblongata

vital centers are located in the...

Base of Brain to Top of Tail Bone

where does the spinal cord start and end

Hypothalamus

where is appetite controlled?

Myelin

white fatty substance formed by Schwann cells that wrap around some axons outside the CNS

Cerebrum

white matter made up of bundles of nerve fibers (tracts) composes most of the interior of the...

Tract

a bundle of nerve fibers (axons) in the CNS

Ganglion

a group of nerve cell bodies located in the PNS

Nerve

a group of peripheral nerve fibers (axons) bundled together like strands of a cable

Cerebrum

largest and uppermost part of brain; mental processes including sensations, consciousness, memory and voluntary control of movements

Cranial Nerves

12 pairs attached to undersurface of the brain; connect brain with the neck and structures in the thorax and abdomen

Spinal Nerves

31 pairs; contain dendrites of sensory neurons and axons of motor neurons; conduct impulses necessary for sensation and voluntary movements

Preganglionic Neurons

autonomic neurons that conduct impulses between the spinal cord and a ganglion

Cholinergic Fibers

axon whose terminals release acetylcholine

Myelinated Fiber

axons outside the CNS that are surrounded by a segmented wrapping of myelin

Adrenergic Fibers

axons whose terminals release norepinephrine and epinephrine

Neurotransmitters

bind to specific receptor molecules in membrane of a postsynaptic neuron, opening ion channels and thereby stimulating impulse conduction by the membrane

Dendrites

braching projections that conduct impulses to cell body of neuron

Alzheimer Disease

brain disorder of the middle and late adult years characterized by dementia

White Matter

brain or cord tissue made up of nerve tracts covered with white myelin

Parkinson Disease

characterized by abnormally low levels of dopamine in motor control areas of the brain; pts usually exhibit involuntary trembling and muscle rigidity

Spinal Cord

columns of white matter composed of bundles of myelinated nerve fibers form the outer portion; inner composed of gray matter made up of neuron dendrites and cell bodies

Postganglionic Neurons

conduct from autonomic ganglia to cardiac muscle, smotth muscle and glandular epithelial tissue

Motor Neurons

conduct impulses away from brain and spinal cord to muscles and glands; also called efferent neurons

Interneurons

conduct impulses from sensory neurons to motor neurons; also called central or connecting neurons

Sensory Neurons

conduct impulses to the spinal cord and brain; also called afferent neurons

Autonomic Nervous System

consists of certain motor neurons that conduct impulses from spinal cord or brainstem to cardiac muscle, smooth muscle and glandular epithelial tissue

Hypothalamus

consists of posterior pituitary gland, pituitary stalk and gray matter; controls ANS and functioning of most internal organs

Brainstem

consists of three parts in ascending order medulla oblongata, pons and midbrain; all 3 parts are two way conduction paths; important reflex centers lie here

Hypothalamus

controls hormone secretion by anterior and posterior pituitary glands; controls appetite, wakefulness, pleasure, etc.

Parasympathetic Nervous System

dominates control of many visceral effectors under normal everyday conditions

Thalamus

dumbbell shaped mass of gray matter; relays sensory impulses to cerebral cortex from sense organs; associates sensations with emotions

Cell Body, Dendrites and Axon

each neuron consists of what three parts

Axon

elongated projection that conducts impulses away from cell body of neuron

Meninges

fluid containing membranes surrounding the brain and spinal cord

Oligodendrocytes

form myelin sheath that envelops nerve fibers located in brain and spinal cord; help hold nerve fibers together

Electroencephalogram

graphic representation of voltage changes in the brain used to evaluate brain activity

Sympathetic Postganglionic Neurons

have dendrites and cell bodies in sympathetic ganglia

Parasympathetic Preganglionic Neurons

have dendrites and cell bodies in the gray matter of the brainstem and the sacral segments of spinal cord

Sympathetic Preganglionic Neurons

have dendrites and cell bodies in the gray matter of the thoracic and upper lumbar segments of the spinal cord

Cerebrovascular Accident

hemorrhage from or cessation of blood flow through cerebral blood vessels; also called a stroke

Neuroblastoma

highly malignant tumor of the sympathetic nervous system primarily affecting young children

Motor Tracts

in the brainstem conduct impulses from the higher parts of the brain to the spinal cord

Sensory Tracts

in the brainstem conduct impulses to the higher parts of the brain

Nodes of Ranvier

indentations between adjacent Schwann Cells are what

Nodes of Ranvier

indentations between adjacent Schwann cells

Huntington Disease

inherited disorder characterized by chorea (purposeless movement) progressing to severe dementia

Central or Connecting

interneurons can also be called what neurons

Schwann Cells

large nucleated cells that form myelin only in the PNS