lecture quiz 1
Pathway of stretch reflex
1. Stretch detected 2. Afferent signal back to SC 3. Activates motor neuron of stretched (agonist) muscle 4. Leads to muscle contraction of agonist 5. Also activates inhibitory interneuron 6. Inhibits activation of motor neuron for antagonist muscle 7. Leads to relaxation of antagonist muscle
How does a receptor send a signal to the CNS?
AP frequency dictated by stimulus strength, sensitivity to stimulus is dictated by receptor threshold
Why are these senses so important?
Need to be aware of dangerous stimuli
Exteroceptors
Respond to stimuli arising outside the body Receptors in the skin for touch and vision
Proprioceptors
Sensory receptors found in muscle and tendons that detect their degree of stretch ex. tendons ligaments joint capsules muscles
receptive field
area covered by 1 receptor
spinal reflexes
automatic reactions to a stimulus that occur without conscious thought BRAIN IS NOT INVOLVED
Proprioceptors
balance receptors
special senses
complex sensory organs located in the head vision, hearing, smell, taste, balance
tonic receptors
continue to send APs with continued stimulus no adaption
pain
dected by nociceptors
Chemoreceptors
detect toxins and chemicals released by dying cells or inflammatory cells (histamine) ex ph oxygen taste smell
Tempature
detected by thermoreceptors
perception
interpretation of those stimuli (CNS)
Deep tendon reflex
involuntary muscle contraction in response to tension
Interoceptors
monitor visceral organs and functions regulate ph, blood pressure, visceral pain
tonic receptor examples
nociceptors and prorioceptors
processing sensory information occurs?
occurs in somatosensory cortex in parietal lobe
Nociceptors
pain receptors
cold
phasic, respond to changes in tempature cooling between 12-35 degrees Celsius
warm
phasic, responds to changes warming between 25-47 degrees Celsius
purpose of stretch reflex
prevent over stretch of muscle receptor on muscle spindle stimulus detected, stretch of muscle
Thermoreceptors
respond to changes in temperature ex cold/hot
Photoreceptors
respond to light ex vision
Mechanoreceptors
respond to touch, pressure, force
phasic receptors
send AP with initial stimulus and with removal of stimulus good for vibration no signal with continued stimulus
sensation
the awareness of changes in internal or external stimuli (periphery)
Stretch reflex
the contraction of a muscle in response to stretch of that muscle (length and position)
the bigger the receptive field
the less precise
phasic receptors examples
touch receptors
general senses
touch temperature pain, found all over body