A&P - Nervous System

communication

the nervous system is one of the major ___ systems of the body

endocrine

what is the other communication system besides the nervous system?

neurons

__ help maintain the homeostasis of the body

central nervous system

consists of the brain and spinal cord

peripheral nervous system

includes the cranial nerves and spinal nerves, connects brain to other body parts

sensory receptors

gather information about what is going on around the body

afferent

bring information to the brain

efferent

bring information from the brain to the body

afferent

are sensory nerves afferent or efferent?

neurons

react to physical and chemical changes in the environment, conduct nerve impulses to other neurons and to cells outside the nervous system

neuroglia cells

supportive cells for nervous system, provide structural support, nutrition, form scar tissue, form myelin, carry out phagocytosis

neurofibrils

provide support for cell processes

Nissl bodies

similar to rough endoplasmic reticulum, in neurons

dendrites

usually many processes extend from the cell body, short and highly branched

neurons

dendrites receive impulses from other ___

dendritic spines

thorn like projections coming off dendrites

axon

conducts nerve impulses away from the cell body

axonal hillock

where the axon comes from

collaterals

branches from the axon

presynaptic terminal/synaptic terminal

ending of an axon

synaptic cleft

the s[ace between neurons

axonal transport

how an axon carries substances produced by the cell body down its length to the end of the axon

ions, nutrients, neurotransmitters

what may be carried by axonal transport? (3)

oligodendrocytes

form myelin in the CNS

Schwann cells

form myelin in the PNS

Schwann cells

neuroglia cells that wrap themselves around some of the larger axons of the peripheral nerves

one

one schwann cell forms __ segment of myelin around an axon

neurolemma

the membrane on the outside of the last wrap of the Schwann cell, surrounds myelin sheath

oligodendrocyte

cell with “hands” that wrap around numerous axons of cells in the CNS

many

one oligodendrocyte produces __ segments of myelin on multiple axons in the brain and SC

false

true or false: oligodendrocytes form neurilemmal sheaths

true

true or false: mature neurons usually do not undergo mitosis

glia

unlike nerve cells, __ cells can reproduce

gliomas

most tumors in the nervous tissue are __

myelinated

axons with myelinated sheaths

unmyelinated

axons that do not have myelinated sheaths

white, white

myelinated fibers are __ and are responsible for the __ matter in the brain and SC

gray, gray

unmyelinated nerve tissue is __ and forms the __ matter of the brain and SC

14th

myelin begins to form during the __ week of development but myelination continues into adolescence

unipolar neuron

neuron with a single process extending from the cell body, divides into 2 branches

dendrite, axon

one branch serves as a __ (connected to peripheral body parts), and the other branch serves as an __ and enters the brain or SC of a unipolar neuron

ganglia

the cell bodies of unipolar neurons are present in ___ that are located outside the SC and brain

PNS, sensory neuron

where is a unipolar neuron found and what type of functional neuron is it?

bipolar neuron

a neuron with two nerve processes extending outward

eyes, nose, ears

where are bipolar neurons found

sensory

what type of functional neurons are bipolar neurons?

multipolar neuron

nerves that have many (3 or more) nerve processes come off the cell body

axon, dendrites

in a multipolar neuron, one process is the __ and all others are __

motor neurons

what type of functional neuron is a multipolar neuron?

multipolar neuron

what is the most common type of neuron based on structure?

sensory neuron

carry impulses from the periphery into the brain or SC

receptor endings

sensory neurons have specialized endings on the dendrites, called __ __

receptor cells

sensory neurons synapse with __ __

unipolar

most sensory neurons are __

ganglia

most sensory neurons have their cell bodies in ganglia

motor neuron

carry impulses from the brain or spinal cord outward to muscles or glands

multipolar

what structure do motor neurons have?

CNS

which system are motor neurons found in?

interneurons/associate neurons

neurons that lie in the SC or brain and connect other neurons, relay signals between different neurons

multipolar

what structure do interneurons have?

neuron

nerve cell

nerve fiber

the axon of a neuron

nerve

a group of nerve fibers

epineurium

connective tissue around the entire nerve

perineurium

connective tissue around a fascicle

endoneurium

connective tissue around the individual axon

spinal nerves

nerves coming to or from the spinal cord and connecting to other body parts

cranial nerves

nerves coming to or from the brain and connecting to other body parts

mixed

what type of nerves are most nerves? (sensory, motor, or mixed)

somatic

refers o the skeletal muscles and skin

visceral

refers to the smooth muscles, glands, and internal organs

voltage

potential energy between opposite electrical charges when separated

volts, millivolts

what is voltage measured in?

potential difference/potential

voltage is measured between 2 points called the __ __

voltage

the greater the difference in the charge between the 2 points, the higher the __

ions

in the body, electrical currents are usually generated by the flow of __ across cell membranes

charge separation

cells have a different number of positive and negative ions on the two sides of the cell membrane, creates a voltage

current

the flow of electrical charge from 1 point to another, can do work

resistance

hindrance to the flow of charge, caused by substances that the current must pass through

insulators

substance that has high electrical resistance

conductors

substance with low resistance to current flow

plasma membrane

resistance to current flow is provided by the __ __

proteins

what are the channels of the plasma membrane made of?

passive/leakage channels

channel that is always open

active/gated channel

channels that provide resistance to current flow

chemically gated

gates that open when the appropriate neurotransmitter binds

voltage-gated channels

channels that open and close in response to changes in the membrane potential, or voltage

mechanically gated

gates that respond to stretch or deformation

ions

each type of channel is usually selective for the __ it allows to pass

chemical gradients

when ions move passively from an area of higher concentration to an area of lower concentration, they are moving along ___ ___

electrical gradients

when ions move toward an area of opposite electrical charge, they are moving along __ __

electrochemical gradient

a combination of chemical and electrical gradients

ions

__ that flow along electrochemical gradients form the basis for all electrical phenomena in neurons

-70 mv

what is the typical resting membrane potential in a neuron?

polarized

a cell membrane is electrically charged or ___

polarization

this is due to unequal distribution of ions on the inside and outside of the cell membrane

K+, Na+, Ca2+

put the following in order from easiest to hardest to pass through pores and channels (Na+, K+, Ca2+)

potassium

because __ passes through easiest it is the major contributor to the membrane potential (polarization)

Na+

when a cell is at rest, the concentration of __ is greater on the outside of the cell membrane

K+

when a cell is at rest, __ is greater on the inside of the membrane