Special Senses Lecture 1 Flashcards
What is the somatosensory system?
part of the sensory system concerned with the conscious perception of touch, pressure, pain, temperature, position, movement, and vibration which arise from the muscles, joints, skin and fascia
What is somatic sensation?
sensation from the skin, muscles, bones, tendons and joints (“relating to the body”
What is somatosensation?
Somatosensation refers to the process that conveys information regarding the body surface and its interaction with the environment
What are the submodalities of somatosensation?
- Touch
- pressure
- temperature
- pain
What receptors are responsible for proprioception?
Mix of joint tendon stretch receptors
The specialized receptor cells generate graded potentials called _______ potentials in response to a stimulus
The specialized receptor cells generate graded potentials called receptor potentials in response to a stimulus
What is the difference between graded potentials and action potentials?
Graded potentials are small depolarizations; if there are enough of these small depolarizations, they can end up generating an action potential
Name the receptor that responds to each of the following modalities:
- Respond to light:
- Respond to pressure:
- Respond to temperature:
- Respond to sound:
Name the receptor that responds to each of the following modalities:
- Respond to light: Photoreceptors
- Respond to pressure: mechanoreceptors
- Respond to temperature: Thermoreceptors
- Respond to sound: auditory receptors
What are five different types of somatosensory (touch and pressure) receptors?
- Meissner’s corpuscles
- mechanoreceptor that responds to touch and pressure
- Rapidly adapting
- Merkel’s corpuscles
- respond to touch and pressure
- slowly adapting
- Free neuron ending
- nociceptor
- thermoreceptor
- mechanoreceptors (slow-adapting)
- Pacinian corpuscle
- vibration and deep pressure
- rapidly adapting
- Ruffini corpuscle
- responds to skin stretch
- slow-adapting
Which of the touch/pressure receptors are slowly adapting? Which are rapidly adapting?
Slow-Adapting:
- Merkel’s
- Free Neuron ending
- Ruffini corpuscle
Rapidly-adapting:
- Pacinian corpuscle
- Meissner corpuscle
How are afferents (mechanoreceptors or somatosensory receptors) activated?
use Meissner’s or Merkel’s as example
- Poke on arm > activates ______ > _____ channels in distal end of receptor open and _____ flows down its concentration gradient into the afferent neuron (or sensory receptor) = _________ _______ of the sensory receptor
Meissner’s and merkel’s corpuscles are somatosensory receptors that are activated by touch or pressure (mechanoreceptors)
- Poke on arm > activates mechanoreceptor > cationic channels in distal end of receptor open and sodium flows down its concentration gradient into the afferent neuron (or sensory receptor) = graded depolarization of the sensory receptor
What are the two types of sensory receptors?
a) sensory receptor is located directly on the afferent fibre
- sesnory receptor is located on the afferent neuron and the afferent neuron travels to the spinal cord
- Na+ flows into the cell resulting in a graded depolarization; AP is not necessarily generated bu that equivalent of an EPSP is generated in the distal end of the receptor cell which is located on the afferent
b) The sensory receptor is located on a specialized receptor cell
* Poke in the arm activates mechanoreceptors > cation channels open > Na+ flows in > graded depolarization > NT released > binds to afferent neuron > spinal cord
Graded potentials are the equivalent of ______ and are small, longer lasting _____ at the location of the sensory receptor in the periphery
Graded potentials are the equivalent of EPSP’s and are small, longer lasting depolarizations at the location of the sensory receptor in the periphery
The afferent fibre of a sensory receptor has a number of _______
Receptor terminals
- the more receptor terminals activated = the more ap’s
What are three important factors that affect our ability to localize a stimulus?
- Density of innervations
- Receptive field size
- Overlapping receptive fields