Lect 23 - neurophysiology 3; sensory receptors

Flashcards on neurophysiology and sensory receptors.

What is the function of afferent signals?

To transmit information to the CNS about our environment and body homeostasis.

What kind of information do somatic senses provide?

Information about the external or internal environment, typically sensed by the skin, muscle, and joints.

Where do visceral senses originate?

Internal organs, providing a generalized sense of well-being.

What are special senses and what are some examples?

• detected by highly specialised organs or structures

• Vision (eyes), smell (nose), and taste (tongue & nose).

What is transduction in the context of sensory receptors?

Conversion of a sensory stimulus into an action potential.

How do tonic receptors respond to stimulation?

They are continually active and slow adapting, reflecting a background level of stimulation.

How do phasic receptors respond to stimulation?

They are fast adapting and normally silent, sending action potentials with a change but stopping quickly.

How do thermoreceptors detect temperature changes and what type of receptor are they?

Via temperature-gated ion channel

• phasic receptors

How does temperature stimuli transduction occur?

Temperature stimuli open temperature-gated Na+ channels, allowing Na+ to enter and depolarize the membrane.

How do chemoreceptors translate changes in chemical concentration and what type of receptor are they?

They use chemically-gated ion channels.

• tonic or phasic receptors

How do mechanoreceptors respond to physical forces and what type are they?

Via mechanically-gated ion channels that respond to deformation of the plasma membrane.

• light touch are phasic

• proprioceptors and baroreceptors are tonic

What is tactile sensation?

Sense of touch, including pressure and scratch of the skin.

What are proprioceptors for?

Sense of body position and movement in space, which comes from stretch receptors in muscles, tendons and joints.

What do baroreceptors detect?

Pressure/stretch in vessels within the body.

What do nociceptors respond to and what type of receptor are they?

Noxious stimuli (harmful, painful) typically cause by tissue damage.

• mainly tonic receptors

What determines the intensity of a sensation?

Action potential frequency and number of neurons activated.

What is a receptive field?

Area encompassed by nerve endings for a single sensory neuron.

How do receptive fields affect sensitivity?

Size and density of receptive fields affect sensitivity and ability to localise a stimulus

What are the characteristics of an area with less sensitivity and less accurate localization?

Large and Widely spaced receptive fields.

What are the characteristics of an area with more sensitivity and more accurate localization?

Small and densely packed receptive fields.