Sensory Receptors Flashcards
(24 cards)
what are afferent signals
signals that are sent to the CNS to give us information about our environment and our body homeostasis
what are efferent signals
the instructions that are sent from the CNS to the rest of the body once the information is processed
what are the 3 types of sensory signals
- somatic senses
- visceral senses
- special senses
what are somatic senses (features)
- the perception of physical senses, like touch and temperature
- can provide information about external or internal environment
- tend to be highly specific in terms of location and direction
- typically sensed by skin, muscle and joints
what are visceral senses (features)
- refers to senses that monitor your internal organs
- often difficult to pinpoint a precise location, instead more of a generalized sense of well being or not
- eg feeling full after a big meal or nauseous when ill
what are special senses (features)
- detected by highly specialized organs or structures
- eg vision, smell and taste
what is sensory transduction
is the conversion of a sensory stimulus into an action potential
what are the 2 types of receptors (time)
- tonic receptors
- phasic receptors
what are tonic receptors (features)
- slow adapting receptors
- continually active to reflect
- AP frequency changes when stimulus changes
what are phasic receptors (features)
- fast adapting
- normally silent (no AP)
- send APs with change but stop quickly
what are the 4 different type of sensory receptors
- thermoreceptors
- chemoreceptors
- mechanoreceptors
- nociceptors
what are thermoreceptors
- are nerve endings with temperature-gated ion channels
- respond to different temperatures and also change in temperature
- are phasic
explain the transduction of temperature stimuli
- temperature stimuli open temp-gated Na channels
- allowing Na to enter and depolarize the membrane
- if threshold is reached in the thermoreceptor, an AP will fire and propagate to the brain
what are chemoreceptors (features)
- are specialised receptor cells with chemically gated ion channels
- translate changes in chemical concentration to action potentials
- can be tonic or phasic depending on the chemical and location
what are mechanoreceptors (features)
- are nerve endings with mechanically gated ion channels
- respond to physical forces that distort the plasma membrane
- light touch receptors are typically phasic
- proprioceptors and baroreceptors are tonic
what are the 3 different types of mechanoreceptors
- tactile sensation
- proprioception
- barorecption
what is tactile sensation
sense of touch, including pressure and the stretch of the skin
what is proprioception
sense of body position and movement in space, which comes from stretch receptors in muscles, tendons and joints
what is a baroreceptor
detect pressure/stretch in vessels within the body
what are nociceptors (features)
- are nerve ending that respond to noxious stimuli typically caused by tissue damage
- have either temperature gated, chemically gated or mechanically gated ion channels responding to extreme stimuli
- tend to be tonic, though some are phasic
what is the intensity of a sensation determined by
- action potential frequency
- number of neurons activated
what is a receptor field
the area encompassed by nerve endings for a single sensory neuron
what determines the localization accuracy of sensation
- number of receptive fields
- size of receptive fields
what part of the brain interpretates somatic signals
the somatosensory cortex of the brain
