nerve quiz

nervous system

master controlling and communication system of the body

changes

what does the nervous system monitor?

input

what does the nervous system process and interpret?

communicates via electrical impulses and causes immediate responses

how does the nervous system effect a response? (2 things)

sensory input

stimuli from hearing, sight, touch, smell, and taste

integration

the processing and interpreting of sensory input

motor output

response

central nervous system and peripheral nervous system

what are the two categories of the nervous system?

central nervous system

brain and spinal cord

acts as integrating and command centers, interprets sensory information, and issue instructions

what are the three jobs of the central nervous system?

peripheral nervous system

any part outside of the CNS, nerves that extend from brain and spinal cord

links body parts, carries impulses, and communication lines between cells

what are the three jobs of the peripheral nervous system?

sensory (afferent) division and motor (efferent) division

what are the two parts of the peripheral nervous system?

sensory (afferent) division

consists of nerves that convey impulses to the CNS from receptors in the body

keeps the CNS informed of events inside and outside of the body

what does the sensory (afferent) division do for the CNS?

somatic sensory fibers and visceral sensory fibers

what are the two parts of the sensory (afferent) division?

somatic sensory fibers

nerve fibers from the skin, muscles, and joints

visceral sensory fibers

nerve fibers from internal organs

motor (efferent) division

carries impulses from CNS to organs, muscles, glands, etc

motor (efferent) division

what acts on organs to bring about response?

somatic and autonomic

what are the two divisions of the motor (efferent) divison?

somatic nervous system

allows conscious or voluntary control of muscles (control of skeletal muscle movement except reflexes)

autonomic nervous system

regulates involuntary events

glands, cardiac muscle, smooth muscle, etc

what does the autonomic nervous system act on?

sympathetic and parasympathetic

what are the two divisions of autonomic nervous system?

sympathetic divison

mobilizes the body in extreme situations, "fight or flight" system

situations that threaten homeostasis

what does the sympathetic division allow the body to cope with?

physical or emotional

what type of stress does sympathetic division deal with?

threats

what does the sympathetic system help the body respond to?

heart rate, blood pressure, respiration rate, sweat, and dilates pupils

what does the sympathetic division increase?

parasympathetic divison

resting division, allows body to conserve energy

blood pressure, heart rate, and respirations

what are at normal levels in the parasympathetic division?

neurons (nerve cells)

specialized cells that transmit nerve impulses

neurotransmitter

chemicals released by neurons that are transferred to other neurons or cells, stimulate a response

structurally

how do neurons differ from each other?

cell body

metabolic center of neuron, contains necessary organelles

processes

fibers that extend from the cell

processes

what vary in length?

dendrites

fibers that convey incoming messages towards the cell body

hundreds

how many dendrites could a neuron have?

dendrites and axons

what are the two types of processes?

axons

fibers that convey incoming messages away from the cell body

one

how many axons are there per neuron?

axon terminal

what is at the end of an axon?

synaptic cleft

what are the axon terminal and next neuron separated by?

myelin sheath

proteins and fatty material (myelin) surrounding nerve fibers

protection, insulation, and increases rate of nerve impulses

what are the three jobs of the myelin sheath?

neuroglia

cells that support, insulate, and protect neurons

glia

what are the different types of neuroglia called for the PNS and CNS?

astrocytes, microglia, ependymal cells, oligodendrocytes

what are the four glial cells for the CNS?

astrocytes

star-shaped cells that cling to neurons and anchor them to capillaries

nutrients and exchange waste with blood

what do astrocytes allow neurons to receive?

harmful substances in blood

what do astrocytes protect neurons against?

half of neural tissue

what do astrocytes account for?

microglia

spider-like cells, monitor health of neurons and removes debris (dead brain cells and bacteria)

ependymal cells

lines cavities of the brain and spinal cord, helps circulate protective fluid (cerebrospinal fluid)

oligodendrocytes

wraps around nerve fibers, produces myelin sheath (only for cells in CNS)

schwann cells and satellite cells

what are the two types of cells in PNS glial cells?

schwann cells

forms myelin sheath around nerve fibers (only in PNS)

satellite cells

forms protective cushion around cell bodies

according to traveling direction of traveling impulses relative to the CNS

how are neurons grouped?

sensory (afferent) neurons

carries impulses from sensory receptors (PNS) to CNS

sensory (afferent) neurons

what keeps CNS informed of information both inside and outside of the body?

touch, pain, pressure, temperature, and stretching

what are sensory (afferent) neurons receptors for?

motor (efferent) neurons

neurons carrying impulses from CNS to organs, muscles, glands, etc

interneurons

(association neurons) connect motor and sensory neurons in neural pathways (cell bodies mainly in CNS)

number processes extending from cell body

how are neurons classified according to?

multipolar neurons

motor neurons, single long axon, many symmetrical dendrites

multipolar neurons

what is the most common neuron?

bipolar neurons

one axon and one dendrite from opposite sides of cell body

bipolar neuron

what is the rarest neuron?

found in retina and olfactory receptors

where are bipolar neurons found?

unipolar neurons

short single process emerging from cell body that divides into central and peripheral processes

end of peripheral process

where do the dendrites of the unipolar neurons branch off?

sensory neurons of PNS and in spine

where are unipolar neurons found?

irritability and conductivity

what are the two functional properties of neurons?

irritability

ability to respond to stimulus and convert it into a nerve impulse

conductivity

ability to transmit the nerve impulse to other neurons, muscles, or glands

a stimulus

what do impulses require?

changing amounts of ions inside and outside of neuron

what are nerve impulses generated by?

resting neurons (inactive), stimulus and depolarization, generation of action potential, propagation of action potential, and repolarization

what are the five steps of a nerve impulse?

polarized

external face of cell membrane is slightly positive and inside cell membrane is slightly negative

K+

what is a major ion inside the cell?

Na+

what is a major ion outside the cell?

impermeable

membrane is _ to both ions

stimulus

what changes the permeability of membrane?

depolarization

Na+ channels open and rush into the membrane, K+ exits

polarity of cell

what changes at that site?

the inside of the cell

what part of the cell becomes more positive at that site?

Na+ influx

what continues down the neuron at step 3?

action potential (nerve impulse)

neuron initiates and transmits long distance signal called...

all or none response

once action potential is generated, neuron must complete the process

adjacent neuron

the depolarization of one neuron causes permeability changes in what?

neurotransmitter

what is passed from one neuron to the next through synaptic cleft?

nerve impulse

what continues down the remainder of the cell?

repolarization

concentration of Na+ and K+ ions restored to original state

excess Na+ pumped out and K+ are allowed in

what is pumped out vs in in step 5?

same direction as depolarization

what direction do these repolarization events spread?

until repolarization finishes

no new impulses can be sent until what happens?

resting state

when the impulse ends what does the nerve enter?