Dermatomes, Peripheral Nerves, and Receptors Flashcards
what is a dermatome?
what is its clinical relevance?
The area of skin supplied by one segment of the spinal cord.
location of a lesion can be determined by which dermatome(s) is/are affected.
what is the dermatome for the first cervical and the coccygeal?
haha! they dont have any because their nerves have no dorsal roots
what will a spinal nerve innervate?
1 somite
what is a somite?
a dermatome, a myotome (muscles) and a sclerotome (bones and ligaments).
what are the dermatomes for the following areas:
- Biceps brachii tendon reflex
- Triceps tendon reflex
- Brachioradialis tendon reflex
- Upper Abdominal superficial reflexes
- Middle Abdominal superficial reflexes
- Lower Abdominal superficial reflexes
- Patellar tendon reflex
- Achilles tendon reflex
- C5-C6
- C6, C7
- C5, C6
- T6, T7
- T8, T9
- T10, T12
- L2, L3, L4
- S1, S2
what is shingles?
is the herpes zoster virus that resides dormant in sensory nerves; when reactivated causes pain and rash in the affected dermatomes
what nerve does shingles affect?
V1 of CN V
Most peripheral receptors utilize what type of nerve fiber?
What nerve fiber do free nerve endings utilize?
Type A-beta
C type fibers
What are the 5 types of sensory receptors?
- Mechanoreceptors
- Thermoreceptors
- Nociceptors
- Electromagnetic receptors
- Chemoreceptors
Sensory receptors can be subdivided into what 2 type of receptors?
- Encapsulated
- Non-Encapsulated
Some receptors are fast adapting and slow adapting, what does this mean?
Rapidly adapting: is used for information about changes in stimulation
Slow adapting: is used for information about ongoing stimulation
- What information do free nerve endings relay?
- Is it fast or slow?
- What can activat these fibers?
- Predominantly pain information, but some touch, pressure, and tickle.
- both fast and slow pain sensation
- Temperature
What information do Merkel’s discs relay?
where can we find merkel’s discs?
how are merkel’s discs nerve fibers?
- Two-point discrimination.
- Superficial skin layers of fingertips.
- Slowly adapting, for pressure.
what are hair-like follicles?
Free nerve endings wrapped around a hair follicle that act as mechanoreceptors (movement activates the free nerve)
what information do Meissner’s corpuscles relay?
are they fast or slow adapting?
- fine touch or two point discrimination and some vibration
- rapidly adapting (fast)
what information do Pacinian corpuscle’s relay?
are they fast or slow adapting?
what is another name for Pacinian corpuscle’s?
vibration mainly and deep pressure
fast adapting
Lamellar bodies
What information do Ruffini’s corpuscle relay?
where do we find Ruffini’s corpuscle?
propioceptive information of muscles and temperature (heat mainly), also stretching in skin (cutaneous)
in subcutaneous tissue and joints
what are Krause’s end bulbs for?
cold sensation
neuromuscular spindles are divided into 2 categories of motor neurons, what are they? where do we find each?
- alpha motor neurons = extrafusal muscle fibers
- gamma motor neurons = intrafusal muscle fibers
There are 2 types of intrafusal muscle fibers?
- nuclear bag
- nuclear chain
what changes occur in order to
receive proprioceptive information about changes in muscle length?
Activation of gamma motor neurons changes the
shape of these intrafusal fibers (nuclear bag and nuclear chain), activates sensory endings wrapped around the intrafusal fibers and then we get propioception of muscle length
what are golgi tendon organs?
how do they work?
What is their purpose?
A ‘capsule’ of loosely arranged tendon fibers.
When the capsule is stretched, free nerve endings inside are activated, and transmit information to the spinal cord, where it synapses on alpha motor neurons.
They provide an inhibitory effect to prevent too much tension on the muscles.
what is a myotactic reflex?
what is a inverse myotactic reflex?
a stretch reflex generated by tapping on a deep tendon
occurs at the same time as a myotactic reflex, and acts in relaxation of the antagonistic muscles.
