Sensory PhysiologySensory Physiology

SensationSensation

Awareness of changes in environment

Changes can be internal or external

How is perception different?

Awareness of changes in environment

Changes can be internal or external

How is perception different?

Sensory modalitiesSensory modalities

Unique type of sensation Two classes:

General Somatic - tactile, thermal, pain, proprioreceptive Visceral

Special Smell, taste, hearing, vision, equilibrium

Each sensory neuron linked to one modality

Unique type of sensation Two classes:

General Somatic - tactile, thermal, pain, proprioreceptive Visceral

Special Smell, taste, hearing, vision, equilibrium

Each sensory neuron linked to one modality

How do we sense?How do we sense?

Process of sensationProcess of sensation

1. Stimulation of receptor2. Transduction of stimulus

(Graded potential)3. Generation of nerve impulses4. Integration of input

1. Stimulation of receptor2. Transduction of stimulus

(Graded potential)3. Generation of nerve impulses4. Integration of input

Receptor classification: Stimulus

Receptor classification: Stimulus

Mechanoreceptors Thermoreceptors Nocireceptors Photoreceptors Chemoreceptors Osmoreceptors

Mechanoreceptors Thermoreceptors Nocireceptors Photoreceptors Chemoreceptors Osmoreceptors

AdaptationAdaptation

What does this mean?Maintained stimulus lessened

potentials decreased impulse frequency

May be rapidly or slowly adapting

What does this mean?Maintained stimulus lessened

potentials decreased impulse frequency

May be rapidly or slowly adapting

Eye Anatomy ReviewEye Anatomy Review

Image FormationImage Formation

1. Refraction of light rays Both cornea and lens refract

1. Refraction of light rays Both cornea and lens refract

Image FormationImage Formation

2. Accommodation Convex surface causes light rays to

converge Greater curvature = greater

refraction Lens more curved for near objects

(ciliary muscle) Near point of vision

2. Accommodation Convex surface causes light rays to

converge Greater curvature = greater

refraction Lens more curved for near objects

(ciliary muscle) Near point of vision

Image FormationImage Formation

3. Constriction of the pupil Iris narrows pupil Restricts light from

periphery of lens Simultaneous with

accommodation

3. Constriction of the pupil Iris narrows pupil Restricts light from

periphery of lens Simultaneous with

accommodation

Refraction abnormalitiesRefraction abnormalities

Myopia

Hyperopia/ Hypermetropia

Astigmatism

Myopia

Hyperopia/ Hypermetropia

Astigmatism

Binocular visionBinocular vision

Advantages/Disadvantages How does it work? Convergence

Advantages/Disadvantages How does it work? Convergence

PhotoreceptorsPhotoreceptors

Rods vs. ConesRods vs. Cones

Structural difference in outer segment

One opsin (rhodopsin) vs. three

Cone regeneration quicker

Rods used for low light, relatively unused in light

Structural difference in outer segment

One opsin (rhodopsin) vs. three

Cone regeneration quicker

Rods used for low light, relatively unused in light

Visual pathwayVisual pathway

SoundSound Waves originating

from vibration Frequency (Hz =

cycle/sec) Pitch Audible range is

20-20,000 Hz Amplitude (dB)

Volume 0 dB = threshold

Waves originating from vibration

Frequency (Hz = cycle/sec) Pitch Audible range is

20-20,000 Hz Amplitude (dB)

Volume 0 dB = threshold

Physiology of HearingPhysiology of Hearing

EquilibriumEquilibrium

Vestibular apparatus - Saccula, utricle, semicircular ducts

Static equilibrium - relative to gravity Utricle and saccula

Dynamic equilibrium - rotation, acceleration, deceleration Semicircular ducts (rotational

acceleration/deceleration) Saccula and utricle (linear acceleration)

Vestibular apparatus - Saccula, utricle, semicircular ducts

Static equilibrium - relative to gravity Utricle and saccula

Dynamic equilibrium - rotation, acceleration, deceleration Semicircular ducts (rotational

acceleration/deceleration) Saccula and utricle (linear acceleration)

Olfaction and GustationOlfaction and Gustation

Olfaction Odorants stimulate olfactory hairs Hairs connected to dendrite Potential

generated Signal sent along olfactory tract

Gustation Five primary tastes Taste buds have receptors Signal sent along gustatory pathway (Three

nerves Medulla Diencephelon/Cerebrum)

Olfaction Odorants stimulate olfactory hairs Hairs connected to dendrite Potential

generated Signal sent along olfactory tract

Gustation Five primary tastes Taste buds have receptors Signal sent along gustatory pathway (Three

nerves Medulla Diencephelon/Cerebrum)