Chapter 9 Flashcards (Sensory System)

These flashcards cover key concepts from the sensory system, focusing on the steps of sensation, types of receptors, sensory pathways, and visual and auditory systems.

What are the 4 steps of sensation?

Stimulus, Transduction (receptor potential), Action potential generation, Integration/perception in CNS.

What is transduction?

Conversion of a stimulus into an electrical signal (receptor potential).

Where does perception occur?

In the brain (cerebral cortex).

What is an adequate stimulus?

stimulus for which a sensory receptor has lowest threshold of activation

What do mechanoreceptors detect?

Touch, pressure, vibration.

What do thermoreceptors detect?

Temperature.

What do photoreceptors detect?

Light.

What do chemoreceptors detect?

Chemicals (taste, smell).

What do nociceptors detect?

Pain.

What is sensory modality?

Type of stimulus (touch, pain, light).

How is modality encoded?

By receptor type and neural pathway.

What determines stimulus location?

Receptive field.

What is a receptive field?

Area where stimulation activates a receptor.

How is stimulus intensity encoded?

Frequency of action potentials.

How is stimulus duration encoded?

By receptor adaptation.

What is sensory adaptation?

Decrease in response over time.

What are phasic receptors?

Fast adapting receptors (detect change).

Example of a phasic receptor?

Touch receptors.

What are tonic receptors?

Slow adapting receptors (continuous response).

Example of a tonic receptor?

Pain receptors.

What is lateral inhibition?

Process where neurons inhibit neighboring neurons. Helps locate stimulus accurately

Function of lateral inhibition?

Enhances contrast and sharpens sensory perception.

What is sensory acuity?

Ability to detect fine detail.

What increases sensory acuity?

High receptor density and small receptive fields.

What are somatic senses?

Senses from skin, muscles, and joints.

What are visceral senses?

Senses from internal organs.

What are special senses?

Vision, hearing, taste, smell, equilibrium.

What does the spinothalamic tract carry?

Pain and temperature.

Where does spinothalamic tract cross?

Early in the spinal cord.

What does the DCML do?

Touch, vibration, proprioception.

Where does DCML?

In the brainstem.

Where does pain project besides somatosensory cortex?

Limbic system (emotion).

What are endogenous opioids?

Natural painkillers (endorphins).

What is gate control theory?

Non-pain signals block pain signals.

What are descending pathways?

Brain pathways that inhibit pain.

what is endogenous analgesia system?

you don’t feel pain when it occurs

What are refractive errors?

Problems focusing light on the retina.

What is myopia?

Near-sightedness.

What is hyperopia?

Far-sightedness.

What is astigmatism?

Uneven curvature of the eye.

What is glaucoma?

Increased pressure in the eye.

What is cataract?

Clouding of the lens.

What is presbyopia?

Age-related loss of near vision.

how do you fix myopia(near-sighted)?

concave lens

how do you fix hyperopia (far-sighted)?

convex lens

how do you fix astigmatism(uneven lens)?

cylindrical lens

What is the visual pathway?

Retina → optic nerve → optic chiasm → brain.

What happens at the optic chiasm?

Partial crossing of fibers.

if someone has bitemporal hemianopia where is this problem occuring?

optic chiasm

if someone has right anopia, where is this problem occuring?

right optic nerve

if someone has left homonymous hemianopia, where is this occuring?

right optic tract

What is the pathway of sound?

Outer ear → eardrum → ossicles → cochlea.

What converts sound into electrical signals?

Hair cells in the cochlea.

What is conductive deafness?

Problem transmitting sound.

how would you treat conductive deafness?

hearing aids

What is sensorineural deafness?

Damage to nerve or cochlea.

how would you treat sensorineural deafness?

cochlear implants

What detects linear acceleration?

Utricle and saccule.

what detects linear acceleration vertically? up and down

saccule

what detects linear acceleration horizontally?

utricle

What detects rotational movement?

Semicircular canals.

what is bone conduction and how does it work?

Bone conduction transmits sound directly through skull bones to the inner ear

what is air conduction and how do it work?

Air conduction is the normal pathway of sound transmission through the ear