Spinal Cord, reflexes and receptors Flashcards
The spinal cord begins where and ends where?
Begins at medulla oblongata to the conus medullaris.
Within spinal cord, what are the 2 enlargements?
Cervical and lumbar
Cervical enlargement is from which the __________ plexus is formed. It innervates the ________ extremities of which vertebraes?
Brachial, upper, C5-T1
Lumbar enlargement is from which the __________ plexus is formed. It innervates the ________ extremities of which vertebraes?
Lumbar, lower, T12, L1-L4
Of the spinal cord you have the anterior median ______ and the posterior median _______.
Fissure (ant), sulcus (pos)
Is the “butterfly” of the spinal cord white or grey matter?
Grey
Surrounding the butterfly of the spinal cord is white or grey matter?
White
Which type of matter contains the bundles of myelinated fibers (tracts)?
White matter
What do the dorsal roots contain?
Sensory neurons
What do the ventral roots contain?
Axons of motor neurons
The dorsal roots and ventral roots come together to form what?
The spinal nerve
The spinal nerve divides into the…
dorsal and ventral rami
What does the dorsal rami supply?
The deep vertebral muscles and skin of the back
What ventral rami supplies what?
All the ventral and lateral musculature.
The denticulate ligaments extend what length?
The length of the spinal cord
Learn the layers of meninges of the spinal cord*** (look up image
:)
WHere does the spinal cord end?
L1/L2 (conus medullaris)
Where do the meninges stop (which vertebrae)?
S2
Definition of receptors.
Structures that are generally activated by changes in, or stimuli from either the internal or external environments of the body.
Define sensation.
a state of awareness of external and or internal conditions of the body.
Define a stimulus.
May be from receptors of light, heat, pressure, mechanical energy, chemical energy, etc
Define perception.
Conscious registration of a sensory stimulus.
Define adaptation.
A decrease in sensation during a prolonged stimulus.
What are free nerve endings?
Uncapsulated or bare nerve endings
Free nerve endings act primarily as…
pain receptors (nociceptors)
Free nerve endings also act as…
touch receptors at hair follicles.
What is Merkel’s disc?
A flat saucer-shaped nerve ending, classified as a free nerve ending.
Are free nerve endings capsulated or noncapsulated?
noncapsulated
What kind of receptors are merkel’s discs?
slow-adapting receptors of light touch.
mechanoreceptors found in the fingertips, hands, lips and external genitalia.
What is meissner’s corpuscle?
A mass of dendrites encapsulated in a connective tissue capsule.
Meissner’s corpuscles are sensitive to what?
Light
Where are meissner’s corpuscles found?
In the skin (esp. finger tips), mucous membrane of tongue, other sensitive regions of the body.
What are pacinian corpuscles?
A multilayered connective tissue capsule surrounding a dendrite.
Pacinian corpuscles are stimulated by what?
Heavy pressure