sensory system flashcards from notes in class, not including eye, ear, smell taste

why is the distance for brail how it is

it is how far apart receptive fields are in your fingertip

homeostatic reflex arc what we focus on

stimulus to receptor to integrating center

All sensory stimuli must be CODED into a language that the _____

can understand (i.e., nerve impulses)

CNS

examples of language the sensory stimuli can understand

nerve impulses

how stuff in brain is processed

receptors/stimulus——→nerve route back—→how in brain it is processed

types of receptors

free nerve endings and separate sensory cells

stimulus

any environment condition which the body can detect

4 special senses

taste, see, hear, smell

transducers

sensation and perception

sensation

any sensory signal which we are aware of (conscious of)

perception

how we consciously interpret the sensation

how do perception and sensation go together

both transducers, tied but not same, work together to interpret stuff but may interpret incorrectly when together

example of sensation and perception not working correctly

feeling heart attack in left arm, perception does not match sensation

when can we sense stimulus’s

if we have sensors for it, ex. if we can detect wind then we have sensors for wind.

example of being able to sense a stimuli inside us

blood stream can detect glucose because they have a receptor that binds to it and tells us how much we have

all nerves understand what

graded potentials and action potentials (impulses in a way)

everytime you see a ______ it is some kind of _____, converting signals

receptor, transducer

transducer

convert one information into another

receptive field

specific region of sensory space where a stimulus can alter electrical activity or firing rate of a given neuron

sensory modality

different types of receptors respond to different types of stimuli, the type of receptor activated communicates the type of sensation involved

photoreceptor sensory stimulus

light

photoreceptor modality

vision (sight)

thermoreceptor sensory stimulus

heat

thermoreceptor modality

temperature

mechanoreceptor sensory stimulus

physical pressure, stretch, strain, or sheering

mechanoreceptor modality

touch, pressure, audition (hearing), position, balance and equilibrium

also hearing, position of arms

chemoreceptor sensory stimulus

chemicals

chemoreceptor modality

olfaction (smell) and gustation (taste)

nociceptor sensory stimulus

injuries (various)

nociceptor modality

pain

all sensory info ends up getting transferred to _____, either ___ or _____

neurons, directly or indirectly

sensory stimuli cause sensory receptors to generate _______ on afferent neurons

graded potentials

types of graded potentials

pacemakers sometimes spontanious

EPSP and IPSP

receptor potentials

pacemaker potential

leaky, doesn’t stay at point slowly goes up

never has stable nesting membrane potential

when stimuli are detected by free nerve endings, what happens

the neurons generate graded receptor potentials that vary in magnitude and direction of change with stimulus change

when stimuli are detected by separate cells (not by free nerve endings), what happens

the receptor cells secrete neurotransmitters then generate EPSPs and IPSPs in proportion to stimulus magnitude

action potentials always ______, commonly change _____

all or nothing, how frequent not how much

sensory stimuli induce changes in _______ along neurons in proportion to stimulus magnitude and direction

action potential frequency

does the magnitude of action potentials change?

no, they are all or nothing

lateral inhibition

improves localization of stimulus origin

stopping something (example covering siblings hand so they can’t talk while you tell your side of the story, the stronger sibling wins)

lateral inhibition google definition

a neural mechanism in which an excited neuron suppresses or reduces the activity of its neighboring neurons

sensory adaptation

reduces the magnitude of the receptors response to non-life-threatining repetitive stimuli

-reduces sensory overload on CNS

-examples of touch, smell, sounds

example of sensory adaptation

ignoring receptors if not needed, not always paying attention to how clothes feel on us

tuning out train noise after hearing so often

free nerve endings

unencapsulated, unspecialized sensory nerve terminals that branch into surrounding tissues without a protective connective tissue capsule.

Separate sensory cell

a specialized non-neuronal cell—usually epithelial in origin—that detects a specific environmental stimulus and then releases a chemical neurotransmitter to activate a connected afferent (sensory) neuron

By “resting” with some pacemaker activity, neuronal responses can show what

DIRECTION of change and not simply MAGNITUDE of change

sensory adaptation receptors classified as either what

fast adapting or slow adapting

what happens if there are overlaping sensory neurons and you get touched there

all get activated

what does a sensory unit consist of

a single sensory neuron along with all the sensory receptors (or receptor endings) connected to it.

somatosensory cortex cortical primary area in:

parietal lobes

visual cortex cortical primary area in:

occipital lobes

auditory cortex cortical primary area in:

temporal lobes

olifactory cortex cortical primary area in:

frontal lobes (and temporal?)

taste cortex cortical primary area in:

parietal lobes

specific ascending pathways

carry single sensory modalities to specific primary sensory areas of the cerebral cortex

What happens when multiple sensory modalities share and use the same axonal bundles leading into the brain?

They form nonspecific ascending pathways.

What are shared interneurons that process multiple sensory modalities called?

Polymodal neurons.

Through which structures do nonspecific ascending pathways travel?

The brain stem, thalamus, reticular formation, and cerebral cortex

What is the primary functional importance of nonspecific ascending pathways?

They are important for maintaining a general sense of alertness and arousal.

what does specific ascending pathways go through

goes up the spinal cord to the brain

somatosensory cortex

receives information about how your body feels

example touch, pressure, pain, temperature

motor homunculus

controls voluntary muscle movements

ex. moving fingers, moving arms, walking moving lips

difference between somatosensory cortx and motor cortex

somatosensory: receives information, motor sends commands

somatosensory tells you what you feel, motor controls what you move

somatosensory is touch, pain, temperature. Motor is voluntary movement

Sensory is sensory input, motor is motor output.

where is somatosensory cortex and motor located at

the cerebral cortex

why are certain body parts bigger in the diagrams showing somatosensory and motor,

require detailed sensory processing or precise motor control

ascending pathway

traveling up from the spinal cord toward the brain

descending pathway

traveling down from the brain toward the spinal cord/body

what happens when you touch something cold

sensory receptors detect temperature change and send signals toward your brain

steps for specific ascending pathway

sensory receptor detects something, sensory neuron carried the information into the spinal cord, the signal travels upward through the spinal cord, it relays through the thalamus, it reaches a specific area of the cerebral cortex.

nonspecific ascending pathway steps

sensory receptors detect a stimulus. Information enters the spinal cord. Signals travel upward toward the brain stem and thalamus. The information is distributed to broader areas of the cerebral cortex

what does nonspecific pathway help brain become aware of

helps become aware that something is happening and contributes to alertness and arousal

example of nonspecific pathway

you notice that there is something touching you

a stimulus gets your attention

you become more alert because something is happening to your environment

comparison of specific ascending and nonspecific ascending pathways

specific is detailed and nonspecific is more general

specific goes to a specific cortical area while nonspecific projects more broadly

specific helps identify what and where. nonspecific help awareness and alertness

specific is more localized and nonspecific is widespread processing

different structures and what they do for ascending pathways

spinal cord carries sensory signals upward

brainstem relays and processes information; involved in alertness

thalamus is the major relay station that directs sensory information toward the cerebral cortex

cerebral cortex processes sensory information so you can consciously perceive it

what area causes the blending of messages in nonspecific pathways

blends in the thalamus?

cerebral cortex

outer layer of the brain responsible for processing sensory information, controlling voluntary movements, and performing higher-level thinking

how does cerebral cortex work

different areas have different jobs but they all communicate together to help understand and respond to the world around you

primary areas in cerebral cortex

receive sensory information and send commands for movement

association areas in cerebral cortex

interpret and give meaning to information

higher-order association areas in cerebral cortex

combine information from multiple senses and support complex thinking (puts everything together)

somatic senses

touch

pressure

stretch (and sheer)

vibration

heat/cold

pain

position and movement

where is the primary somatosensory cortex located

parietal lobe, just behind the central sulcus

stereognosis*

be able to recognize an object by touch without looking

cortical association areas do what

combine information from multiple sensory modalities to develop complex sensory analysis

stimulus

something that activates a sensory receptor

epidermis

outermost layer of skin

provides a protective barrier

dermis

located underneath the epidermis

contains blood vessls, glands, nerves, and many sensory receptors

contains free nerve endings and merkel cell complexes near epidermis. and then ruffini’s corpuscles and pacinian corpuscle and meissner corpuscle

free nerve endings

like dendrites, bare branching nerve endings

function: detect pain, temperature, itch, and some crude touch

located going into the epidermis, in the dermis

Meissner’s corpuscles

function: detect light touch and low-frequency vibrations

located in dermis close to the epidermis

pacinian corpuscles

function: detects deep pressure and high-frequency vibrations

deeper in the dermis

Ruffini endings

function: detect skin stretch and sustained pressure

located deeper in the dermis

when you pull, twist your arm or feel something slipping from your fingers

Merkel discs

function: detect sustained light touch, edges, shapes, and texture. feels various types of pulls meaning feels subtle changes in way skin is pressed

basal layer of the epidermis

why should you not let partner reasure you while giving birth

because gentle touch agrivates other pains, grab them by arm and squeeze them

why are free nerve endings called free

they arent surrounded by a specialized connective tissue capsule

corpuscles (encapsulated nerve endings)

nerve endings surrounded by layers of connective tissue that forma a capsule

gives mass to ends of free nerve endings

which nerve endings have corpuscles

meissner, pacinian, ruffini

proprioception

the sense of bodily position, extended or flexed arms

knowing where your body is

maintains posture with kinesthesia

kinesthesis

sense of movement at joints

knowing how your body is moving

maintains posture with proprioception

nociception

detecting potential harmful stimulus

receptors that make proprioception and kinesthesia possible

muscle spindles, golgi tendon organ, joint mechanoreceptors