central nervous system: afferent

acuity

(n.) sharpness (particularly of the mind or senses)

ependymal cells

-barriers beyween compartments - source of neural stem cells

adequate stimulus

form of energy to which a receptor is most responsive

Schwann cells

form the myelin sheath around axons of PNS neurons and participate in axon regeneration

axon

functions as the output portion of the neuron by generating action potentials and then propagating them toward another neuron, muscle fiber, or cell

lateral inhibition

increases contrast between activated receptive fields and inactive neighbors

-which sensory neurons are activated -where neurons terminate in brain

modality is indicated by...

motor neurons

most ___ ____ have numeerous dendrites and one main axon extending from their cell bodies

microglia

remove cellular debris formed during normal development of the nervous system and phagocytize microbes and damaged nervous tissue

Thermoreceptors

respond to changes in temperature

Oligodendrocytes

responsible for forming and maintaining the myelin sheath around axons of neurons in the CNS

interneurons

responsible for integration- they process incoming sensory information from sensory neurons and then elicit a motor response by activating the appropriate motor neurons

photoreceptors

responsive to visible wavelengths of light

detection

to the stimulus

detects, encodes, and transmits

3 processes of afferent divison

modality, location, intensity, duration

4 properties of stimulus

astrocytes, oligodendrocytes, microglia, and ependymal cells

4 types of neuroglia in CNS

tonic receptors

adapt slowly or not at all

CNS myelin

____ ___ is one of the factors inhibiting regeneration of neurons

action potential

a receptor of sufficent magnitude can produce

dendrites

a stimulus in the brain causes a graded potential to form in the _____ and cell body of an upper motor neuron

action potentials

action potentials awlays depolarize followed by repolarizing and return to resting potential

CNS

afferent neurons coney action potentials into the

tight junctions

astrocyte processes surrounding brain capillaries secrete chemicals that maintain the tightness of these ___ ____

neuroglia

astrocytes are the most nuemorus __

K+

astrocytes regulate the concentration of ions such as ___

cell body

because of its ability to direct protein synthesis and other activities, the _____ ___ functions as control center of neuron

false

binding of some neurotransmitters to their receptors always results in the opening of ion channels in postsynaptic membranes

tract

bundle of axons in CNS

nerve

bundle of axons in PNS

compound sensations

by combining combinations of sensory modalities, our brain can produce nonspecific sensations such as wetness

receptor potential

change in sensory receptor membrane potential

intensity

coded by frequency of action potentials

perception

conscious awareness of sensation

PNS

consists of all nervous tissue outside the CNS

motor tracts

consists of axons that carry action potentials away from the brain

sensory tracts

consists of axons that conduct action potentials towards the brain

motor areas

control execution of voluntary movements

medulla

controls involuntary actions such as breathing

brain stem

controls many life sustaining processes, such as respiration, blood pressure, and digestion

efferent neurons

convey action potentials away from the CNS to effectors in the periphery

Afferent division of PNS

conveys input into the CNS from sensory receptors in the body

somatic nervous system

conveys output from the CNS to skeletal muscles only

ANS

conveys outputs from the CNS to smooth muscle, cardiac muscle and glands

association areas

deal with the more complex integrative functions such as memory, emotions, reasoning, will, judgement, personality traits, and intelligence

osmoreceptors

detect changes in concentration of solutes in body fluids and resultant changes in osmotic activity

motor areas

direct skeletal muscle movement

proportional

duration of a series of action potentials is _____ to stimulus duration

sensory receptors

either the peripheral endings of sensory neurons or separate cells located close to sensory neurons

true

glia do not generate or propagate action potnetials

true

graded may be hyperpolarizing or depolarizing

astrocytes

help maintain the appropraite chemical environment for the generation of action potentials

false

in CNS there is repair of an axon after injury

chemoreceptors

include receptors for smell and taste and receptors that detect O2 and CO2 concentration in blood and chemical content of digestive tract

visceral afferent

incoming pathway from organs

ion channels

initiate membrane potential change

neurotransmitter

nerve action potnetial travels along the axon of interneuron, which results in ______ release at the next synapse with another internueron

glia

nourish and protect neurons and maintain homeostasis in the intersitial fluid that bathes them

brain stem

oldest region of brain

cerebral cortex

once internuerons in the ____ ____ are activated, perception occurs and you are able to feel the smooth surface of the pen touch your fingers

motor function

once sensory information is integrated, the CNS may elicit an appropriate response

non-specific cation

once the stimulus happens the opening of what channels occurs

nocieptors

pain receptors that are sensitive to tissue damage or distortion of tissue

CNS

processed sensory information, generates thoughts,emotions and memories, stimulates muscles to contract and glands to secrete

ependymal cells

produce and assist in the circulation of cerebrospinal fluid

phasic receptors

rapidly adapt to a constant stimulus and turn off

dendrites

recieve signals from stimuli in the environment and function as main input portion of neuron

hypothalamus

recieves sensory input from receptors for vision, taste, and smell

transmits

send action potential into CNS

sensory afferent

sensation arsiging from body surface and proprioception

mechanoreceptors

sensitive to mechanical energy

one

sensory neurons have how many process(S) that extend from their cell bodies

encodes

sensory transduction: mechanical stimulus----> electrical (AP)

dendrties

short, highly branched processes that extend from the cell body

secrete

stimulation of the effectors causes muscles to contract and glands to

permeability

stimulus leads to change in membrane ____

sensory receptor

structure that monitors changes in the external or internal environment

nerve action potential

the graded potnetial triggers the axon of the sensory neuron to form a ____ ___ ___

interneuron

the neurotransmitter stimulate the ____ to form a graded potential in its dendrites and cell body

cerebral cortex

what manipulates a picture so that we think it is moving