Nervous system part 2 Flashcards
what is a reflex?
rapid and automatic response triggered by specific stimuli
Where does the cervical enlargement innervate?
the shoulder and upper limbs
Where does the lumboscaral enlargement innervate?
pelvis and lower limbs
What is the conus medullaris?
tapered, conical portion of the spinal cord interior to the lumbar enlargement
Where does the adult spinal cord end?
between L1 and L2
What is the caudal equina?
A complex of long anterior and posterior roots of the spinal cord that resemble a horses tail
What is the film terminale
a slender strand of fibrous tissue that extends from the inferior tip of the conus medullaris to the second sacral vertebra
provides longitudinal support to the spinal cord as a component of the coccygeal ligament
What is the posterior median sulcus?
A shallow longitudinal groove on the posterior surface of the spinal cord
What is the posterior root?
contains the axons of the neurons whose cell bodies are in the posterior root ganglion
What is the posterior root ganglion?
contains the cell bodies of sensory neurons whose axons carry info to the spinal cord
What does a spinal nerve contain?
axons of sensory and motor neurons
What is the anterior root?
contains the axons of motor neurons that extend into the periphery to control somatic and visceral effectors
What is white matter dominated by in the spinal cord?
myelinated axons with few or no neuronal cell bodies
What is grey matter dominated by in the spinal cord?
The cell bodies of neurons, neuroglia, unmyelinated axons
What do the spinal meninges consist of?
dura mater, arachnoid mater, pia mater
What is the pia mater?
meshwork of elastic and collagen fibres that is bound to the neural tissue underneath
What is the arachnoid mater?
the middle meningeal layer made of simple squamous epithelium (arachnoid membrane), and the subarachnoid
What is the dura mater?
outermost covering of the spinal cord– contains dense collagen fibres that go longitudinally
What is the subarachnoid space? What is it filled with?
- made of arachnoid trabeculae, a network of collagen and elastic fibres that attaches the arachnoid mater to the pia mater
- cerebral spinal fluid
What is the epidural space filled with? where is it located?
- areolar tissue, blood vessels, adipose tissue
- between dura mater and the walls of the vertebral canal
What is the function of denticulate ligaments?
- prevents lateral movement of the spinal cord
What does the anterior, posterior and lateral gray horns of the spinal cord consist of?
anterior: somatic motor nuclei
posterior: somatic and visceral sensory nuclei
lateral: visceral motor nuclei (only in thoracic/lumbar)
What are gray commissures?
anterior/posterior sections of gray matter around the central canal
- axons that cross from one side of the cord to the other before they reach a destination in the gray matter
How is white matter organized?
it is divided into three regions called columns (posterior white, lateral white, and anterior white)
- the columns contain tracts
Which direction do ascending and descending trans convey motor commands?
ascending: sensory information does towards the brain
descending: motor commands go to the spinal cord
What is the facilitation of motor neurons involved in reflexes called?
reinforcement
What is the procedure for the Babinski reflex?
stroking an infant’s foot on the lateral side of the sole to make the hallux extend and other toes fan out
What is the procedure for the plantar reflex?
stroking an adult’s foot on the lateral side of the sole to make the toes curl
what is the abdominal reflex?
stroke the skin of the abdomen causes contractions of abdominal muscles that pull navel towards the stimulus
