spinal cord 7.1 lecture Flashcards
What nerves make up the coccygeal plexus and what does it supply?
S4-S5 and coccygeal 1
skin in the coccygeal plexus
what does the radial nerve supply?
muscles of the posterior aspect of the arm
what is monoplegia?
paralysis of one limb
What is the shape and length of the spinal cord?
roughly oval
42-45 cm (16-18 in)
What are the 5 important nerves that come from the brachial plexus?
- axillary nerve
- the musculocutaneous
- the radial nerve
- the median nerve
- the ulnar nerve
somatic reflexes involve what
contraction of the skeletal muscles
How many pairs of cervical nerves and where do they exit from?
8 pairs
C1-C7 exit the vertebral canal above their corresponding vertebrae
C8 exits between vertebrae C7 and T1
integration for a cranial reflex takes place where
the brain stem
what does the anterior ramus serve?
serves the muscles and structures of the upper and lower limbs and the skin of the lateral and anterior surfaces of the trunk
what is multiple sclerosis
the immune system damages the nerve mylenation
What are the two tracts of the posterior white column?
gracile fasciculus and cuneate fasciculus
what does the posterior dorsal ramus serve?
deep muscles and skin of the posterior surface of the trunk
what is paraplegia
paralysis of both lower limbs
what happens when the long thoracic nerve is injured?
paralysis of the serratus anterior muscle which causes the medial border of the scapula to protrude which is called winged scapula
what does the brachial plexus supply nerves to?
the shoulders and upper limbs
how many lumbar nerves
5 pairs
exit the vertebral canal below their corresponding vertebrae
what is a reflex
a fast, involuntary, unplanned sequence of actions that occurs in response to a particular stimulus
The spinothalamic tract conveys nerve impulses for sensing
pain, warmth, coolness, itching, tickling, deep pressure, and crude touch
what is quadriplegia
paralysis of all 4 limbs
define crossed extensor reflex
polysynaptic, intersegmental, and contralateral, synchronized with the flexor response
maintains balance by extending the contralateral limb during the withdrawal response of the other limb
what is shingles
an acute infection of the PNS by the same virus that causes chicken pox. The virus stays in the spinal ganglion after infection and can reemerge and travel down the sensory neurons of the skin causing a painful rash.
Integration for a spinal reflex takes place where
spinal gray matter
which spinal nerves make up the brachial plexus
C5-C8 and T1
what does the ulnar nerve supply?
anteromedial muscles of the forearm and most of the muscles of the hand
What are the two main functions of the spinal cord in homeostasis?
nerve impulse propagation and integration of information
the grey matter of the spinal cord receives and integrates incoming and outgoing information
what is spinal shock
an immediate response to spinal cord injury characterized by temporary areflexia or loss of reflex function
what are dermatones?
certain segments of the skin are supplied by spinal nerves that carry somatic sensory nerve impulses to the brain
basically a map on the skin of which spinal nerve it correlates with
What are the 5 main plexuses
cervical plexus brachial plexus lumbar plexus sacral plexus and a smaller coccygeal plexus
define flexor/withdrawal reflex
polysynaptic, ipsilateral, and intersegmental, causes withdrawal of a limb from stimuli to avoid injury or pain
multiple spinal cord segments activate multiple motor pathways to cause the movement
what is hemisection
partial transection of the cord
define a stretch reflex
It is monosynaptic and ipsilateral (nerve impulses enter and exit on the same side of the spinal cord), causes contraction of a muscle that has been stretched. Helps avert injury by preventing overstretching of muscles
At the same time, a polysynaptic reflex arc to the antagonistic muscles operates at the same time. It involves three neurons and two synapses.
Can also help maintain posture.
What spinal nerves make up the cervical plexus?
C1-C4
autonomic/visceral reflexes involve what
Responses of the smooth muscle, cardiac muscle, and glands. not usually perceived
what does the meningeal branch of the spinal nerve supply
the vertebrae, vertebral ligaments, blood vessels of the spinal cord, and meninges
define the femoral nerve?
Originates from L2-L4
innervates the flexor muscles of the hip joint, extensor muscles of the knee joint, skin over the anterior and medial aspect of the thigh, and medial side of the leg and foot.
what is the name of the structure where the spinal cord terminates and where is it?
conus medullaris L1-L2
what is poliomyelitis
Polio, virus that can cause paralysis by destroying motor neuron cell bodies. Fever, headache, stiff neck, muscle pain.
define a tendon reflex
polysynaptic and ipsilateral, causes relaxation of the muscle attached to the stimulated tendon
prevents muscle injury due to excess muscle tension
the sensory receptors for this reflex are called tendon organs/golgi tendon which lie within a tendon near it’s junction with a muscle
Where are the two spinal enlargements?
cervical C4-T1
lumbar T9-T12
what are the three functions of the spinal cord?
process reflexes
integrate EPSPs and IPSPs
conduct sensory impulses to the brain and motor impulses to the effectors
what does the cervical plexus supply?
the skin and muscles of the head, neck, superior portion of the shoulders and chest, and diaphragm
Includes the phrenic nerve
what happens when the radial and axillary nerve is injured?
wrist drop
what is amyotrophic lateral sclerosis (ALS/Lou Gehrig’s)
A nervous system disease that weakens muscles and impacts physical function.
what is a polysynaptic reflex arc
involves more than two types of neurons and more than one CNS synapse
define the obturator nerve
Originates from L2-L4.
innervates the adductor muscles of the hip joint, and skin over the medial aspect of the thigh.
what does the axillary nerve supply?
the deltoid and teres minor muscles
what spinal nerves make up the sacral plexus and what does it supply?
L4-L5 and S1-S4
buttocks, perineum, and lower limbs
How many pairs of spinal nerves are there?
31
what is hemiplegia
paralysis of one side of the body
what is a complete transection
a complete cut of the spinal cord that results in a loss of all sensations and voluntary movement below the level of the cut
how many sacral nerves and how many coccygeal nerves
5 pairs
1 pair
Define the filum terminale/terminal filament
an extension of the pia mater that extends below the cauda equina and fuses with the arachnoid mater and dura mater and anchors the spinal cord to the coccyx
What are the two main routes for sensory receptor impulses?
spinothalamic tract and posterior column
the posterior white column tract conveys nerve impulses for
discriminative touch, light pressure, vibration, and conscious proprioception
What is a reflex arc or circuit
the pathway followed by nerve impulses that produce a reflex
what is dipelgia
paralysis of both upper or both lower limbs
Which spinal nerves create the lumbar plexus?
L1-L4
what does the musculocutaneous nerve supply?
the anterior muscles of the arm
what does the median nerve supply?
most of the muscles of the anterior forearm and some of the muscles of the hand
Where does the spinal cord begin and end?
begins around the foramen magnum as an extension of the medulla oblongata and ends at around L2. In infants it extends until L3/L4.
What does the lumbar plexus supply?
anterolateral abdominal wall, external genitals, and parts of the lower limbs
what is a monosynaptic reflex arc
a reflex pathway having only one synapse in the CNS
what can cause spinal cord compression?
fractured vertebrae, herniated intervertebral discs, tumors, osteoporosis, and infections
How many thoracic nerves
12 pairs
they exit below their corresponding vertebrae
what are the rami communicantes?
branches of the spinal nerve that are components of the autonomic nervous system
what three things protect the spinal cord?
vertebrae (bone), meninges (connective tissue), and CSF (fluid)
