peripheral nervous system and sensory receptors Flashcards
(24 cards)
perception at the cortical level is usually _______
conscious
perception at the level of the cerebellum is considered _________
unconscious
what is the “threshold for stimulation”
the amount of stimulus energy it takes to cause a local receptor potential
how many types of stimulus can a single nerve respond too?
only one. Each nerve is specialized to only encode for either heat, sound, touch, smell, etc.
what determines the intensity of a stimulus?
the SIZE of the receptor potential and the NUMBER of receptors activated. The stronger the stimulus the larger the size of receptor potential and number of receptors. This leads to greater FREQ of action potentials
where on the body are the greatest amount of receptive fields and smallest receptor fields?
tongue and fingertips
what is the filum terminale?
it is connective tissue between the end of the spinal cord and the sacrum
what is the lumbar cistern?
a fluid filled area around the cauda equina
what is obstructive hydrocephalus?
blockage of regular CSF flow
where does obstructive hydrocephalus occur?
interventriucular foramen, cerebral aqueduct, and the outflow from the fourth ventricle
what is communicating hydrocephalus?
absorption or circulation problems with CSF. EX. the CSF cant exit the arachnoid granulations due to high venous pressure
what do primary (dynamic) nerve endings encode for?
velocity of stretch
what do secondary (static) nerve endings encode for?
length of stretch
what do golgi tendon organs encode for?
tension of the muscle
what is autogenic inhibition?
a protective role by the GTO that inhibits alpha motor neurons to prevent damage to the muscles from overload of tension
what type of nerve fibers do cold afferents travel over?
type III (or A-ᵹ) and C fibers
what type of nerve fibers do warm afferents travel over?
C only
what temperature do cold afferents respond to?
10-33 degrees C
what temp do warm afferents respond to?
32-45 degrees C
what are the primary nerve endings of nociceptors?
free nerve endings
A-ᵹ mechanoreceptive nociceptors
have a high threshold for stimulation. Primary stimulus is sharp pain, allows for discrimination between sharp and dull pain.
A-ᵹ mechanothermal nociceptors
respond to heat between 45-53 C. Responsible for first pain from intense thermal stimuli as well as intense mechanical stimuli
C-polymodal nociceptors
make up the majority of the cutaneous receptors. Activated by thermal, mechanical, and chemical. Made up of free nerve endings
muscle and joint nociceptive afferents
have both A-delta and C fibers. A-delta is activated by muscle stretch/contraction. C is activated by mechanical or chemical stimuli. Both sensitized to inflammation and signal high background firing in response to it
