Lect 6 Flashcards
Somatic senses
Touch, temperature, pain, itch, proprioception
Proprioception
Awareness of the body position
Receptive field
Physical area where a stimuli activates a neuron
What are the 4 groups of receptors
Chemoreceptors O2, pH
Mechanoreceptors : pressure, vibration
Thermoreceptors: temperature
Photoreceptors: light
Why size determine sensitivity
Because sensitive areas have smaller receptive fields
Less sensitive areas have lathers receptive field
What is sensory modality
Is that the sensory neuron is activated with its specific stimulus
Ex : you won’t have the stimuli of hearing in your hand
What is the location of the stimulus
Which receptive fiel is activated
What is lateral inhibition
Higher contrast between activated receptive field and their inactive neighbours
What is population coding
Multiple neurons function together to send the CNS more Information that would be possible form a single receptor
Intensity of the stimulus
Number of receptors activated and frequency coding
Higher intensity more neurotransmitter
What is the duration of the stilamus l
Duration of action Potential
Explain the receptors of the duration of the stilamus
Tonic receptors : slowing adapting receptors that fire rapidly when 1st activated then slow and maintain firing as long the stimulus is present
Physic receptor : rapidly adapting receptors that dire when 1st receive but cease of the stimulus is constant ex clothes
What is the pathway of a pain and temperature receptor
Primary sensory neuron will come to the spinal cord where another neuron ( interneuron) will take place. The interneuron will do a cross over form the gray matter to the white matter and go to the thalamus where a third neuron will send a message to the somatosensory cortex
What is the pathway of touch receptor
The first neuron will come until the spinal cord where an interneuron will go to the spinal cord to the thalamus and it will cross over in the medulla. A third neuron will go from the thalamus to the somatosensory cortex
What is paricinian corpsuscles
Composed of nerve ending, found in the subcutaneous layers of skin and muscle
What is merkel receptors
Greater in finger tips responsible for the high sensitivity
Touch receptor is stimulated by
Stretch, pressure, vibration, texture, stroking movements
Skin temperatures receptors
It’s the thermoréceptors that will be activated by it
Colder receptors : temperature bellow than the body temperature
Warm receptors : 37-45 is the warm receptors above 45 pain receptors are going to be activated
What is a nociceptor made and what it will respond to
Nociceptor has free nerve ending and will Reponds to a strong noxious stimulus that may damage tissue
Where nociceptors is found
Skin bones muscle but not CNS
What is the 2 neurons that activates pain
2 types of sensory
A alpha and C fibers
Explain explain how a pain is detected
So the first pain that you feel it’s detected by the A alpha fibers it is called the fast pain. This is an sharp and localized pain. The second pain that you feel is a slow pain a burning type of type this is of the C fibers
True or false
Is itch a Type of nociceptors
True
What is an inflammatory pain
Increased sensitivity to pain at site of injury
What cemucals mediate inflammatory responses
K+, histamine, prostaglandin, serotonin and substance p
What are the 2 pathways that nociceptors activate
1) reflexive protective responses that are integrated at the level of the spinal cord
2) ascending pathways to the cerebral cortex that become conscious sensation
Withdrawal reflex
Protective reflexive response to pain
Ex you accidentally touched a hit stove the withdraw reflex causes you to pull your hand even before you are aware of the heat
Ischemia
Lack of adequate blood flow that reduced oxygen supply also occur in heart attach
What is Referred pain.and give an example
Visceral pain is poorly recognized and may be felt in areas far removed from the site of of the stimulus
Ex pain of cardiac ischemia may be felt in the neck and down the left shoulder and arm
What is chronic pain
Pathological pain reflects damage to or long terms changes to nervous system
