Topic 4: Senosry Physiology

Actin Potential

A rapid , transient reversal of a neuron’s membrane potential that propagates along the axon, carrying an electrical signal

• An elelctrical signal that travels along a neutron

Axon

The long, slender projection of a neuron that conducts action potentials away from the cell body toward other cells

• Long part of a neuron that carries the signal away from the cells body

Chemical Senses

Sensory modalities (Taste, smell) that detect chemical stimuli, typically via receptor binding to specific molecules

• Detect chemicals, such as taste and smell

Depolarization

A shift in a cell’s membrane potential to a less negative ( more positive ) value, often the first step toward triggering an action potential

• Cell becomes less negative/ more positive

Electromagnetic Senses

Sensory modalities that detect electromagnetic stimuli, such as light, electric fields, or magnetic fields

• Detect light, electric fields, or magnetic fields

Electroreception

The ability to detect electric fields, used by some fish and other animals for navigation, communication, or prey detection

• Ability to detect electric fields / prey detection

Infrared detection

The ability to sense infrared (heat) radiation

Lens

Transparent structure in the eye that focuses light onto the retina

Ligand -gated ion channel

A membrane channel protein that opens or closes in response to the binding of a specific chemical , allowing ions to flow and change membrane potential

• Channel that opens or close when a chemical binds to it

Magnetoreception

The ability to detect Earth magnetic field, used by some animals for orietation and nagivation

• Ability to detect Eath’s magnetic field for orientation and navigation

Mechanical senses

Sensory modalities ( touch, hearing) that detect physical/ mechanical stimuli such as pressure, vibration or stretch

• Detect physical forces, such as pressure, vibration, stretch

Mechanorepcetor

A senosry receptor that responds to mechanical stimuli such as pressure, stretch or vibration

• Receptor that detects pressure, stretch, or vibration

Neuron

A specialized electrically excitable cell that transmits infromation as electrical and chemical signals

• Specialized cell that transmits infromation using electrical and chemical signals

Opsins

Light sensile protein in photoreceptor cell that undergo a conformational change upon absorbing light, initialting phototransduction

• Light sensitive proteins that respond to light in photorecpetor cells

Photorecpetion

The ability to detect light, enabling vision and other light- dependent responses

• Ability to detect light

Receptor

A specialized cell or structure that detects a stimulus and initiates a sensory signal

• Cell or structure that detects a stimulus

Retina

Light senstive layer of tissue at the back of the eye containing photoreceptor cell that convert into neutral signals

• Light senstive layer at the back of the eye that converts light into neural signals ( back of the eye)

Stimulus

A detectable change in the internal or external evironment that can trigger a response in an organism

• A change in the evironment that can cause a response

Transduction

The process by which a recpetor converts an environmental stimulus into an electrical ( or chemical) signal that the nervous system can process

• Converts a stimulus into a signal the nervous system can process

How physical stimuli become electrical signals

• Stimulus: A change in the environment, like light, sound, pressure, or chemicals

• Receptor : Detects the stimulus

• Trasduction: The receptor converts the stimulus into an electrical signal.

• Action potential THe electrical signals travels along the neuron/ axon to carry the infromation

Three sensory subcategories

• Chemical sense: detects chemicals

Example : taste and smell

• Mechanical sense: Detect physical forces

Example: touch, hearing, pressure, vibration, and stretch

• Electromagentic sense : detect electromagnetic stimuli

Example : Ligh, electric fields, and magnetic fields

Forms of sensory infromation + receptors

Auditory : Hearing → mechanoreceptor

Gustatory: Taste → Chemorecpetors

Olfactory: Smell → Chemoreceptor

Visual: Vision/ light → Photoreceptors

Somatosensory : Touch, pressure, vibration, stretch → Mechanoreceptor

Electrorecpetion: Eletric fields → Elelectroreceptors

Magnetoreception: Magnetic fields → Magnetreceptors

Infrared detection : Heat/infrared radiation → infrared receptors

• Easy way to remmber

Auditory ( hearing ) → mechanoreceptor

Gustatory ( taste) → chemorecpetor

olfactory (Smell) → chemoreceptor

Visual ( vision / light ) → Photoreceptor