Ch.11,12,13,14- anatomy

When it goes above threshold it's ________________

"all or none"

resting state

(-70 mV) all gated Na+ and K+ channels are closed

depolarizing phase

(inside the membrane becomes less negative) Na+ channels open

repolarizing phase

(restores resting membrane potential) Na+ channels are inactivating and K+ channels are open

resting membrane potential

-70mV. means everything is working the right way. membrane of resting neuron is polarized, and the potential difference of this is polarity. exists only across the membrane

Ohm's Law

-Current (I) is directly proportional to voltage. The greater the voltage (potential Difference), the greater the current. -There is no net current flow between points that have the same potential, as you can see by inserting a value of ) V into the equation. -Current is inversely related to resistance. The greater the resistance, the smaller the current.

functions of nervous system:

-gathering sensory input from sensory receptors -processing and interpreting sensory input to decide an appropriate response. -using motor output to activate effector organs, muscle and glands, to cause a response.

***(RMP)resting membrane potential

1. Na+ voltage gated channels open 2. depolarization occurs Na+ flows in 3. Na+ channels close (fast channel-close quickly) (b) K+ (potassium) channels open-it will flow out because it was pumped in. 4. repolarization occurs K+ flows out. 5. K+ (potassium) channels close (slow channel). 6. hyperolzation occurs 7. resting membrane potential, -70 ( back to where we started).

Terminal Branches And Axon terminals (terminal boutons)

10,000 or more __________ Per neurons is not unusual. The knoblike distal endings of the terminal branches are called ____________

there are 6 types of neuroglia- _______ in CNS and _____ in the PNS

4,2

Syphilis

A bacterial infection usually spread by sexual contact that starts as a painless sore

Spastic paralysis

A chronic pathological condition in which the muscles are affected by persistent spasms and exaggerated tendon reflexes because of damage to the central nervous system .

Parkinson's disease

A disorder of the central nervous system that facets movement often including tremors

Sulci

A groove of furrow especially one in the surface of the brain

Ventricles

A hollow part or cavity in an organ lined with ependymal cells and are filled with cerebrospinal fluid

Motor areas

A part of the central nervous system concerned with muscular action, especially the motor cortex

Alzheimer's disease

A progressive disease that destroys memory and other important mental functions

Gyri

A ridge in the cerebral cortex

Poliomyelitis

A virus that may cause paralysis and is easily preventable by the polio vaccine

Sensory areas

An area of cerebral cortex that receives afferent nerve fibers from lower sensory areas

Cerebrum

Anterior part of the brain in vertebrates located in the front area of the skull consisting of two hemispheres

Decussation of the pyramids

Anterior part of the lower medulla oblongata in which most of the fibers of each pyramid intersect

Nerve Fiber

Any long axon is called a ________.

Neurofibrils

Are bundles of intermediate filament, are important in maintaining cell shape and integrity. They form a network throughout the cell body.

Action Potentials

Are long-distance signals of axons.

Epidural space

Area between dura mater and the vertebral wall. Continuing fat and small blood vessels

Processes

Armlike __________ extend from the cell body by all neurons.

Concussion

Brain injury caused by a blow to the head or violent shaking of the head and body

Pons function

Breathing, communication between different parts of the brain hearing, taste , balance

TIA (transient ischemic attack)

Brief stroke attack that , despite resolving within minutes to hours, still requires immediate medical attention to disguising from an actual stroke

Hydrocephalus

Build up of fluid in the cavities deep within the brain

Spinal cord

Bundle of nerve fibers and associated tissue that is enclosed in the spine and connects nearly all parts of the body to the brian

Tracts and Nerves

Bundles of neuron processes are called ______ in the CNS and _____ in the PNS.

efferent division of the PNS transmits impulses from the

CNS to effector organs, which are the muscles and glands

The basic pattern of the CNS consists of a

Central cavity surrounded by a gray mater core, external to which is white matter

Leakage or nongated channels

Channels that are always open.

Nuclei

Clusters of cell bodies in the CNS.

Meninges

Collective term for the 3 membranes covering the brain and spinal cord

Neuron Cell Body

Consists of a spherical nucleus with a conspicuous nucleolus surrounded by cytoplasm.

The Central Nervous System

Contains both myelinated and nonmyelinated axons. However, in the ________ it is the oligodendrocytes that form myelin sheaths.

Astrocytes

Control the chemical environment around the neurons, where their most important job is "mopping up" leaked potassium ions and recapturing and recycling released neurotransmitters.

Cerebrum -2 hemispheres, connected by

Corpus callousness

Stroke

Damage to Brian from interruption of its blood supply

CVA (cerebrovascular accident )

Damage to brain from interruption of blood supply

Depolarization

Decrease in membrane potential: The inside of the membrane becomes less negative (moves closer to zero) than the resting potential.

Where is grey matter found in spinal cord?

Deep inside its core and the insulating white matter wrapped around the outside

The third ventricle lies within the

Diencephalin and communicates with the lateral ventricles via two intervene rivulet foramina

Two factor generate the resting membrane potential:

Differences in ionic composition of the intracellular and extracellular fluids, and differences in the permeability of the plasma membrane to those ions.

Medulla oblongata function

Digestion, sneezing,swallowing

The paired lateral ventricles lie deep within

Each cerebral hemisphere and are separated by the septum pellucidum

Central Process

Enters the CNS

The ventricles are lined with

Ependymal cells and are filled with cereospinal fluid

Axon Collaterals

Extend from the axon at more or less right angles.

Since the brain grows more rapidly than developing skull, The brain forms folds, allowing it to

Fit inside the space of the skull

The lateral and median apertures within the

Fourth ventricle connect the ventricles with the subarachnoid space surrounding the brain

5 lobes

Frontal, partiental, temporal, occipital , insula

Lipofuscin

Harmless by-product of lysosomal activity, is sometimes called the "aging pigment" because it accumulates in neurons of elderly individuals.

Neurons

Have an exceptionally HIGH METABOLIC RATE and require continuous and abundant supplies of oxygen and glucose. They cannot survive for more than a few minutes without oxygen.

Neurons

Have extreme longevity. Given good nutrition, they can function optimally for a lifetime. Neurons ARE amitotic.

The fourth ventricle lies in the

Hindbrain and communicates with the third ventricle via the cerebral aqueduct

Neurons

In many _______, the transition from local graded potential to long distance action potential takes place at the axon hillock.

Contusion

Injured tissue or skin in which blood capillaries have been ruptured ;a bruise

Functions of frontal lobe

Involved in planning organizing , problem solving , selective attention, personality

Action Potentials

Is a brief reversal of membrane potential with a total amplitude of about 100 mV. Depolarization is followed by repolarization and often a short period of hyperpolarization.

Hyperpolarization

Is in increase in membrane potential: the inside of the membrane become more negative (moves further from zero) than the resting potential.

white matter

Is responsible for communication between cerebral areas and the cerebral cortex and lower CNS centers

Prefrontal cortex

Is the cerebral cortex which covers the front part of the frontal lobe

Interneurons *Almost all Multipolar.

Lie between motor and sensory neurons in neural pathways and shuttle signals through CNS pathways where integration occurs.

Oligodendrocytes

Line up along the thicker nerve fibers in the CNS and wrap their processes tightly around the fibers, producing an insulating covering called a *Myelin Sheath*

Where is grey matter?

Located on surface of brain

Paralysis

Loss ability to move in part or most of the body typically as result of illness

Primary somatosensory cortex

Main sensory receptive area for the sense of touch

Myelin Sheath

Many Nerve fibers, particularly hose that are long or large in diameter, are covered with a whitish, fatty, segmented______________.

Potential difference

Measure of voltage between two points. The greater the __________ the higher the voltage.

Broca's area

Motor speech area that controls muscles involved in speech production. Small area of cortex on the medial surface of each cerebral hemisphere

Anterograde Movemnet

Movement away from the cell body is _____.

Retrograde Movement

Movement in the opposite direction is_________

the rising phase of the action potential is due to

Na+ flow into the cell body

The brain and spinal cord begin as the

Neural tube, which rapidly differnatiares into CNS

The ventricles of the brain are continuous with

One another and with the central canal of the spinal cord

Voltage Gated Channels

Open and close in response to changes in membrane potential.

Mechanically Gated Channels

Open in response to physical deformation of the receptor.

Chemically Gated

Open with appropriate chemical binds.

In the brain the cerebrum and cerebellum have an

Outer gray matter later, which is reduced to scattered gray matter nuclei in the spinal cord

Hemiplegia

Paralysis of one side of the body NOTE: not usually spinal injury

Functions of the partiental lobe

Protection of the brain, support the face

Receptive or Input regions

Provide an enormous surface area for receiving signals from other neurons.

Ependymal Cells ("wrapping garment")

Range in shape from squamous to columnar, and many are ciliated.

Association areas

Region of the Cortes of the brain that connects sensory and motor areas, and that is thought to be concerned with higher mental activities

Wernicke's area

Region of the brain concerned with language, located in the cortex of the dominant temporal lobe. Damage in the area causes wernicke's aphasia.

White Matter

Regions of the brain and spinal cord containing dense collections of myelinated fibers are refereed to as _____.

Brain stem general function

Regulating of the heart rate , breathing , sleeping and eating

Astrocytes

Shaped like delicate branching sea anemones, _______ are the most abundant and versatile glial cells. Play a role in making exchanges between capillaries and neurons, helping to determine capillary permeability

Graded Potentials *Called Graded Potential because their magnitude varies directly with stimulus, the more the voltage changes and the farther current flows. Triggered by some change in neuron's environment that opens gated ion channels.

Short lived, localized changes in membrane potential that can be either depolarization or hyperpolarization.

Microglial Cells

Small and ovoid with relatively long "thorny" processes.

Sodium-Potassium Pump (Na+ -K+ ATPase)

Stabilizes the resting membrane potential by maintaining the concentration gradients for sodium and potassium.

Chromatophilic Substance

Stains darkly with basic dyes.

Neurons (Nerve Cells)

Structural unites of the nervous system. They are typically large highly specialized cells that conduct messages in the form of nerve impulses from one part of the body to another.

SIDS

Sudden infant death syndrome

Satellite Cells

Surround neuron cell bodies located in the peripheral nervous system, and are thought to have many of the same functions in the PNS as astrocytes do in the CNS.

Schwann Cells

Surrounded all never fibers in the PNS and form myelin sheaths around the thicker nerve fibers. Vital ti regeneration of damaged peripheral nerve fibers.

Meninges

The 3 membranes that line the skull and vertebral canal and enclose the brain and spinal cord

Conducting Region

The axon is the __________ of the neuron. In generates nerve impulses and transmits them, typically away from the cell body, along the plasma membrane.

The medical scheme of the brain anatomy divides the adult brain into four parts:

The cerebral hemispheres, the diencephalic, the brain stem and the cerebellum

Gray matter

The darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching sentries

Current

The flow of electrical charge from one point to another.

Resistance

The hindrance to charge flow provided to charge flow provided by substances through which the current must pass.

Axon Hillock

The initial region of axon arises from a cone shaped area of the cell body called the ___________

Spinal cord anatomy

The major column of the nerve tissue that is connected to the brain and lies within the vertebral canal and from which the spinal nerves emerge. 31 pairs of spinal nerves onginate in the spinal cord: 8 cervical , 12 thoracic , 5 lumbar , 5 sacral and 1 coccygeal

Voltage

The measure of potential energy generated by separated charge, is measured in either volts (V) or Millivolts. (1 mV =0.001 V).

Resting Membrane Potential

The minus sign indicates that the cytoplasmic side (inside) of the membrane is negatively charged relative to the outside. This potential difference in a resting neuron is called the ____________.

Outer collar of perinuclear cytoplasm.

The portion of Schwann cell, next to the exposed part of its plasma membrane is called ________.

The neural tube develops constructions that divide the three primary brain vesicles :

The prosencephalon (forebrain) , mesenvephalon (midbrain), and rhombensephalon (hindbrain)

Microglial Cells

Their processes touch nearby neurons, monitoring their health, and when they sense that certain neurons are injured or in other trouble, the microglial cells migrate toward them.

Ependymal Cells ("wrapping garment")

They line the central cavities of the brain and the spinal cord, where they form a fairly permeable barrier between the cerebrospinal fluid that fills those cavities and the tissue fluid those cavities and the tissue fluid bathing the cells of the CNS. The beating of their cilia helps to circulate the cerebrospinal fluid that cushions the brain and spinal cord.

Dendritic Spines

Thorny appendages having bulbous or spiky ends- which represent points of close contact (synapses) with other neurons.

Ganglia

Those that lie along the nerves in the PNS.

Electrochemical Gradiant

Together, electrical and concentration gradients constitute the _______.

Nerve Impulse

Typically generated only in axons. A neuron generates a nerve impulse only when adequately stimulated. The stimulus changes the permeability of neurons membrane by opening specific voltage-gated channels on the axon.

Pseudounipolar Neurons

Unipolar Neurons are more accurately called _____ because they origiinate as bipolar neurons. Then during early embryonic development, the two processes converge and partially fuse to form the short single process that issues from the cell body.

Graded Potentials

Usually incoming signals operating over short distances.

Additional protection of spinal cord

Vertebrae protect the spinal cord. The vertebrae are separated by disks made of cartilage, which act as cushion

Midbrain function

Vision,hearing,motor control, sleep, wake, arousal, temperature regulation

Current

Voltage (V) = ------------------------- Resistance (R)

Flaccid paralysis

Weakness or paralysis and reduced muscle tone without other obvious cause

Neurotransmitters

When impulse reaches the axon terminals, it causes _____- signaling chemicals usually stored in vesicles--- to be released into extracellular space.

Receptor Potential

When the receptor of a sensory neuron is excited by some form of energy, the resulting graded potential.

Postsynaptic Potential

When the stimulus is a neurotransmitter released by another neuron, the graded potential is called _______.

Motor, or efferent, neurons *Also Multipolar.

_____ Carry impulses away from the CNS to the effector organs of the body periphery.

Gray Matter

_____ Contains mostly nerve cell bodies and nonmyelinated fibers.

Multipolar Neurons (Major neuron type in CNS)

_____ Have three or more processes- one axon and the rest dendrites.

Bipolar Neurons

_____ Have two processes- an axon and a dendrite- that extend from opposite sides of the cell body.

Positive Ions

_____ Ions migrate toward more negative areas (the direction of cation movement is the direction of current flow).

Myelin

_____ Protects and electrically insulates fibers, and it increases the transmission speed of nerve impulses.

Neutrons

_____ are grouped structurally according to the number of processes extending from their cell body.

Axon

_____ as generating and transmitting an impulse.

Unipolar Neurons

_____ have a single short process that emerges from the cell body and divides T-like into proximal and distal branches.

Peripheral Process

_____ is often associated with sensory receptor.

Myelin sheath and Thickness

______ , and its ____ depends on the number of spirals.

Ions

______ Move along chemical concentration gradients when they diffuse passively from an area of their higher concentration to an area of lower concentration.

Negative Ions

______ Simultaneously move toward more positive areas.

Neurons

______ uses changes in their membrane potential as communication signals to receive integrate, and send information.

Myelinated Fibers and Nonmyelinated Fibers

_______ conduct nerve impulses rapidly, whereas _______ conduct impulses more slowly. *Note that mylein sheaths are associated only with axons. Dendrites are ALWAYS nonmyelinated.

Sensory, or afferent, neurons

_______ transmit impulses from sensory receptors in the skin or internal organs toward or into the central nervous system. All_____ are unipolar , and their cell bodies are located in sensory ganglia outside the CNS.

Myelin Sheathe gaps, or Nodes of Ranvier

________ occur at regular intervals (about 1 mm apart) along a myelinated axon.

Dendrites

__________ of motor neurons are short, tapering, diffusely branching extensions.

Oligodendryctes

__________Has multiple flat processes that can coil around as many as 60 axons at the same time.

specific receptor

a cell or group of cells that recieves stimuli

the chief contributer to the negative charge of a resting neuron's intracellular fluid is ___________.

a high intracellular concentration of anionic proteins

lidocaine

a medication used to numb tissue in a specific area (to treat ventricular tachyardia).

cell death

about 2/3 of neurons die before birth. many cells also die due to apoptosis during development

the period after an initial stimulus when a neuron is not sensative to another stimulus is the _______.

absolute refractory period

axon terminal

action potential comes down them

saltatory action potential (AP)

action potentials along myelinated axons from one node to the next node, increasing in conduction

multiple sclerosis

affects mostly young people, it gradually destroys myelin sheaths in the central nervous system, reducing them to nonfunctional hardened lesions called scleroses.

primary motor cortex

allows conscious control of precise, skilled, skeletal muscle movements

excitatory post synaptic potential (EPSP)

allows it to be less negative

bipolar neuron

almost always sensory neurons, has two extensions

acetylcholine

always excitatory, first identified; best understood

some examples of neurotransmitters

amino acids, glutamate, aspartate, D-serine, GABA, glycine, monoamines

reverberating (or oscillating) circuits

are characterized by feedback by axon collaterals to previous points in the pathway resulting in ongoing stimulation of the pathway.

diverging (or amplifying) circuits

are common in sensory and motor pathways. they are characterized by an incoming fiber that triggers responses in ever-increasing numbers of fibers along the circuit

converging circuits

are common in sensory and motor pathways. they are characterized by reception of input from many sources and a funneling to a given fircuit, resulting in strong stimulation or inhibition.

neuronal pools

are functional groups of neurons that intergrate incoming information from receptors or other neuronals pools and relay the information to other areas.

schwann cells (in PNS)

are glial cells of the PNS that surround nerve fibers, forming myelin sheath.

satallite cells (in the PNS)

are glial cells of the periferal nervous system whose function is largely unknown . they are found surrounding neuron cell bodies within ganglia

schwann cells (in the PNS)

are glial cells of the periperal nervous system that surround nerve fibers, forming myelin sheath

satallite cells (in PNS)

are glial cells of the pros whose function is largely unknown. they are found surrounding neuron cell bodies within ganglia

microglia cells

are small and ovoid with relatively long "thorny" processes. their processes touch nearby neurons, monitoring their health and when they sense a certain neuron are injured or in trouble, the microglial cells migrate toward them.

neurons

are specialized cells that conduct messages in the form of electrical impulses throughout the body. function optimally for a lifetime, mostly amithotic and have high metabolic rate requiring oxygen and glucose.

chemical synapse

are specialized for release and reception of chemical neurotransmitters

premotor cortex

area of motor cortex lying within the frontal lobe of the brain

Neuroglia in the CNS inlude

astrocytes, microglial cells, ependymal cells, and oligodendrocytes.

neurons have to connected or they go through

atoposis

serial processing

attending to and processing all items simutaneously

axon structure

axon hillock, distal endings called axon terminals, and neurotransmitters released.

neurotransmitters are released from?

axon terminals

G-protein

bind to guanine nucelotides

cranial nerves carry impulses to and from the

brain

central nervous system(CNS)

brain and spinal cord, which occupy the dorsal cavity

certain psychoactive drugs exert their effects by keeping the concentration of neurotransmitters elevated within the synapse. these drugs could act by __________.

by doing neither (A) inhibiting enzymes associated with the postsynaptic membrane that degrade the neurotransmitter and (B) inhibiting reuptake of the neurotransmitter by astrocytes or the presynaptic terminal.

efferent

carries impulses from the central nervous system to effector organs, which are muscles and glands

afferent

carries impulses toward the central nervous system from sensory receptors located throughout the body

visceral sensory fibers

carry impulses from organs within the ventral body cavity.

somatic sensory fibers

carry impulses from receptors in the skin, skeletal muscles and joints.

association neuron (interneuron)

central nervous system, one of three neurons found in the human body. create neural circuits, enabling communication between sensory or motor neurons and central nervous system.

hyperpolarization

change in cell's membrane potential that makes it more negative. some K+ channels remain open, and Na+ channels reset.

repoloarization

change in membrane potential that returns to a negative value just after the depolarization phase of action potential.

membrane proteins:

channel proteins (leakage channels), sodium and potassium pump (more potassium than sodium pumps 3 potassium out for every 2 sodium)and gated proteins

neurotransmitter

chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse

which of the following synapse types is the most rapid?

chemical synapse

central nervous system (CNS)

complex nerve tissues that controls the activities of the body. in vertebrates it comprises the brain and spinal cord of the nervous system.

interneurons (association neurons)

conduct impulses between sensory and motor neurons, or in central nervous system integration pathways.

motor (or efferent) neurons

conduct impulses from the central nervous system to effectors

sensory (or affernet) neurons

conduct impulses toward the central nervous system from receptors

the most important thing a neuron can do is they

connect and send a synapse message

sensory areas

conscious awareness of sensation, visual areas

somatic nervous system

consists of somatic motor nerve fibers tat conduct impulses from the central nervous system to skeletal muscles and allow conscious (voluntary) control of motor activities.

autonomic nervous system

consists of visceral motor nerve fibers that regulate the activity of smooth muscles, cardiac muscles and glands.

ganglia

contains a number of nerve cell bodies, typically linked by synapses, often forming a swelling on a nerve fiber.

motor areas

control voluntary movement

summation

cumulative action or effect, the process by which a sequence of stimuli that are individually inadequate to produce a response are cumulatively able to induce a nerve impulse.

axon

each neuron has a single axon that arises from the axon hillock and generates and conducts nerve impulses from the cell body to the axon terminals

conductor

electrical impulses down periferal nervous via action potential

when considering the relationship between a structural classification of neurons, it can be said that _____.

essentially all bipolar neurons are sensory neurons

have to go through whole action potential before __________________________________________.

gates can open again

nerve fiber classification

grouped based on diameter signal conduction velocity, and myelination state of axons

bipolar neurons

have a single axon and dentrite

unipolar neurons

have a single process extending from the cell body that is associated with receptors at the distal end

channel proteins

have leakage proteins it goes from high to low

electrical synapse

have neurons that are electrically coupled via protein channels and allow direct exchange of ions from cell to cell

multipolar neurons

have three or more processes

an inhibitory postsynaptic potential (IPSP) is associated with ________.

hyperpolarization

What is an axon?

impulse generating and conducting region

nodes of Randvia

in between shwan cells

graded potentials

incoming short distance signals. are short-lived local changes in membrane potentials, can either be depolorizations or hyperpolarization, and are critical to the gneration of action potentials.

sodium ion concentration in the cytoplasm of a neuron ____________ when its voltage-gated sodium channels open.

increases

generally speaking, opening chloride channels in the postsynaptic membrane will result in an _______.

inhibitory postsynaptic potential

association areas

integrate diverse information

automatic nervous system

involuntary system consisting of visceral motor nerve fibers that regulate the activity of smooth muscle, cardiac muscle and glands.

motor neuron

involves the skeletal muscle made up of symatic nervous system, smooth muscle made up of aeronautic nervous system, gland- made up of aeronautic nervous system. peripheral nervous system.

leak channels

ion channels which are always open; responsible for the resting membrane potential

herpes virus

is an infection that causes herpes. herpes can appear in various parts of the body, most commonly on the genitals or mouth. there are 2 types of the herpes

Peripheral nervous system (PNS)

is outside the central nervous system

peripheral nervous system

is part of the nervous system outside the CNS

denalatecyclase

it's an enzyme, speeding up chemical reaction. opens up a channel, and the one next to it (opens a lot of channels)

neurons

key to neural communicataions

myelinated

lack voltage-gated channels along the myelinated internodes

neurotransmitters

language of nervous system, most neurons make two or more neurotransmitters, neurons can exert several influences

ion channels that are always open are called ____________channels.

leak

ependymal cell(in CNS)

line the central cavities of the brain and spinal cord and help circulate cerebrospinal fluid.

oligodendrocytes

line up along the thicker nerve fibers in the central nervous system and wrap their processes tightly around the fibers, producing an insulating covering called myelin sheath.

action potentials

long distance signals of axons. occur on axons and are the principle way neurons communicate

depolarization

loss of polarization, loss of difference in charge between the inside and outside of the plasma membrane

pumps

low to high

GABA

major inhibitory neurotransmitter in the nervous system, results in hyperpolarization

multipolar neuron

many extensions come off of the neuron cell body, almost always sensory and motor neurons.

nervous system

master control and communication

neuroglia

may support the thin neurons in the nervous system. are closely associated with neurons

voltage

measure of the amount of difference in electrical change between two points, called potential difference

microglial cells(in CNS)

monitor health and perform defense functions for neurons

cotransport

more than one ion in a direction

symport

more than one material, in one direction, opposite directions

antiport

more than one material, moving in same direction

glutimate

move across symatic cleft. major excitatory nurotransmitter in the nervous system

action potential

move uni directional down the soma, nerve impulse is a trransient allertion of the membrane potential across an excitable membrane

passive

movement of materials across the cell membrane

glutamate

moves across somatic cleft. major excitatory neurotransmitter in the nervous system.

in what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external enviornment? the interior is _________.

negatively charged and contains less sodium

facilitated zone

neuron synapses with other neurons in pool

the substance released at axon terminals is to propagate a nervous impulse is called a(n)_______.

neurotransmitter

postsynaptic potentials

neurotransmitters receptors cause graded potentials that vary in strength

propagation of action potential

occurs as the local currents of an area undergoing depolarization cause depolarization of the forward adjacent area

uni port

one substance, one direction

gated channels

open and close. ALWAYS high to low. group of transmembrane ion channel proteins which open to allow ions such as Na+, K+ to pass through the membrane in response to binding of chemical messenger

voltage-gated channels

open in response to a change in membrane potential

mechanically gated channels

open when a membrane receptor is physically deformed

chemically gate channels

open when the appropriate chemical binds

chemically gated channels

open when the appropriate chemical binds

sensory neuron

peripheral nervous system, are nerve cells within the nervous systemresponsible for converting stimuli from organism's enviornment into internal electrical impulses.

special summation

process by which stimuli that are individually inadequate to produce response

uni polar neuron

process extends from the cell, almost always sensory neurons

neuron cell body

produces protein, protein that get embedded into the body, contains some pigments (pigments that are found in the back of the eye- based upon wave lengths that allow you to see color).

receptor proteins

protein molecule that recieves chemical signals from outside a cell

functions of neuroglia

provides a protective and supportive network, form myelin, protect, support, and maintain equilibrium in your nervous system.

ependymal cells

range in shape from squamous to columnar and are many ciliated.they line the central cavities of the brain and spinal cord, where they form a fairly permeable barrier between the cerebrospinal fluid that fills those cavities and the tissue fluid bathing the cell of central nervous system.

synaptic delay

rate limiting step of neural transmission. limit synaptic delay by adding more neurotransmitter

astrocytes(in CNS)

regulate the chemical environment around neurons and exchange between neurons and capillaries.

astrocytes

shaped like delicate branching sea anemnes, they are the most abundant and versatile glial cells. they support and brace the neurons and anchor them to their nutrient supply lines. they play a role in making exchanges between capillaries and neurons, helping determine capillary permeability.

dentrites

shorter in length than axons. recieveing regions. receptive area. produce dentric spines. cell processes that are receptive regions of the cell and provide surface area for recieveing signals from other neurons

somatic sensory fibers convey impulses from the

skin, skeletal muscles and joints

voltage gated channels

sodium and potassium, class of transmembrane proteins that form ion channels that are activated by changes in electrical membrane

the neuron cell body

soma, the major biosynthetic center containing the usual organellels except for centriules

"trigger"

something that sets off a disease in a person

axon hillock

specialized part of the cell body of a neuron that connects to the axon.

spinal nerves carry impulses from the

spinal cord

role of sodium-potassium pump

stabilizes the resting membrane potential by mainting the concentration gradients for sodium and potassium

polarized

state of the resting cell, net negative charge

All or none principle

strength by which a nerve or muscle fiber responds to a stimulus

neurons (nerve cells)

structural/function unit, do not divide on their own, live 100 years old, use glucose at a high rate, and have a cell body, multiple cytoplasm extensions. positive and negative charged ions.

the location at which a neuron interacts with its target cell (another neuron or a muscle cell or other effector cell) is called the _______________.

synapse

action potential

the change in electrical potential with the passage of and impulse along the membrane of the muscle or nerve cell.

resting membrane potential is generated by

the distribution of ions and its diffusion across the membrane.

current

the flow of electrical charge from point to point, and is dependent pm voltage and resistance

resistance

the hinderance to charge flow provided by substances through which the current must pass

threshold

the level that must be reached for an effect to be produced, as the degree of intensity of stimulus

saltory conduction is made possible by ____________.

the myelin sheath

PNS consists of

the nerves(bundles of axons) that extend from the brain and spinal cord.

motor output

the nervous system activates effector organs-the muscles and the glands-to cause a response

integration

the nervous system processes and interprets sensory input and decides what should be done at each moment

sensory input

the nervous system uses its millions of sensory receptors to monitor changes occuring both inside and outside the body.

insulator

the surrounding of space within material designed to prevent entrance or escape of radient energy

neurilemma

the thin sheath around a nerve axon

action potential is an all or none phenomena

they either happen completely, in the case of a threshold stimulus, or not at all, in the event of subthreshold stimulus

summate

to add together, total, sum up

Axons and dentrites DO NOT ___________ ____________.

touch each other

viseral sensory fibers

transmit impulses from the visceral organs

neuron function:

transmit signals through the body.

potential difference

two points in and electrical charge

neurons generally repolarize once the membrane potential reaches appoximately +30 mV because _____________.

voltage-gated potassium channel gates open

discharged zone

volume rte of water flow

The autonomic nervous system (ANS) is also called involuntary nervous system because

we generally can not control such activities as the pumping of our heart or the movement of food through out digestive tract.

myelin sheath

whtish, fattu.begin to fold or wrap around axon/ cell membrane, wrap around more than two times, wrap around about 4 times. shwan cells insulate. individual axons are an insulator.

oligodendrocytes(in CNS)

wrap around neuron fibers, forming myelin sheath