06/05/2023 Notes Flashcards
What are the two functions of the spinal cord and nerves?
Provide a pathway for sensory and motor impulses, and responsible for reflexes
What are the 5 regions of the spinal cord?
Cervical, thoracic, lumbar, sacral, and coccygeal regions
What region of the spinal cord is continuous with the medulla oblongata?
Cervical region
Why do the regions of the spinal cord not match up with their adjacent vertebrae?
Vertebrae grow at a much faster rate than the spinal cord, which means the spinal cord tends to be shorter than the spine
What is the conus medullaris?
The tapered, narrow end of the spinal cord that marks the official end of the spinal cord and is usually found at L1
What is the cauda equina?
A group of axons inferior ot the conus medullaris
What is the filum terminale?
A thin strand of pia mater that anchors the conus medullaris to the coccyx
Why are the spinal cord regions that control the upper and lower limbs large/enlarged?
Due to higher numbers of neuron cell bodies, and more space is occupied by axons and dendrites
What is the cervical enlargement?
Inferior cervical region of spinal cord that contains neurons that innervate upper limbs
What is the lumbosacral enlargement?
Extends through the mid-lumbar region of the spinal cord and innervates lower limbs
How many pairs of spinal nerves are there?
31
All spinal nerves are _____ nerves.
Mixed
How many spinal nerves are in each region specifically?
8 cervical nerves, 12 thoracic nerves, 5 lumbar nerves, 5 sacral nerves, and 1 coccygeal nerve
The spinal cord meninges is _____ with the cranial meninges
Continuous
What are the structures that enclose the spinal cord, starting with the outermost layer?
Vertebrae, epidural space, dura mater, subdural space, arachnoid mater, subarachnoid space, pia mater
What can be found in the epidural space?
Loose connective tissue, blood vessels, and adipose connective tissue
Where can local anesthetic be administered prior to parturition?
Within the epidural space to deaden sensation from the waste downwards
How many layers are in the spinal dura mater?
1
What is the function of the spinal dura mater?
Provide stability to the spinal cord and extends between adjacent vertebrae at each intervertebral foramen
What fills the subarachnoid space?
Cerebrospinal fluid
What composes the pia mater?
Elastin and collagen fibers
What is the peripheral white matter of the spinal cord?
Provides a way of neural communication to and from the brain and is composed primarily of myelinated axons
What do the ascending tracts of the peripheral white matter do?
Conduct impulses from the peripheral sensory regions of the body to the brain
What do descending tracts do in the peripheral white matter?
Conduct motor impulses from the brain to muscles and glands
What is the central gray matter in the spinal cord responsible for?
Acts as a center for spinal reflexes
What is found in the gray matter of the spinal cord?
Dendrites and cell bodies of neurons and glial cells and unmyelinated axons
What fills the central canal, and what is the central canal continuous with?
CSF; central canal is continuous with medulla and ventricles of brain
What do spinal nerves connect the CNS to?
Muscles, glands, and receptors
What are dermatomes?
Specific segments of skin that are supplied by a spinal nerve
Which spinal nerve does NOT innervate a segment of skin?
C1
What is referred visceral pain?
Pain or discomfort from an organ that may be mistakenly referred to a dermatome
Why does referred visceral pain occur?
The CNS misinterprets impulses from separate sources because neurons from the same spinal segment innervate both the visceral and superficial regions
What are two common sites of referred visceral pain that is useful in medical diagnosis?
Cardiac Problems and Kidney Disease
Where can referred pain from a heart attack be felt?
Left pectoral region and/or medial side of left arm due to the heart receiving sympathetic innervation from T1-T5 of the spinal cord
Where can referred pain from kidney and ureter pain be felt?
Inferior abdominal wall of the groin and loin regions since the T10-L2 dermatomes overlie the same regions
What spinal nerves do NOT form nerve plexus?
Thoracic spinal nerves and nerves S5-Co1
What are nerve plexus?
Axons from various spinal nerves extend to body structures through several different branches
If a spinal cord/nerve is damaged, will the region that it innervates lose function?
No, since multiple nerves will go through the same area which will only result in partial loss of innervation in a muscle of region of skin
What are the four principal nerve plexus?
Cervical, brachial, lumbar, and sacral
What spinal nerves for the cervical nerve plexus?
Spinal nerves C1-C4 with some contribution from C5
What does the cervical nerve plexus innervate?
Anterior muscles of the neck, and skin of the neck with portions of the head and shoulders
What is the phrenic nerve and responsibilty?
Formed primarily by spinal nerve C4 with parts of C3 and C5 that innervate the diaphragm
What is singultus?
Hiccups
What are the brachial nerve plexus?
A network of spinal nerves formed from C5-T1 that innervate upper limbs
What do the brachial nerve plexus innervate?
Pectoral girdle and entire upper limbs
What 5 major nerves are found in the brachial nerve plexus?
Axillary, Median, Musculocutaneous, Radial, and Ulnar Nerves
What is the axillary nerve’s responsibility?
Innervate deltoid and teres minor AND receives sensory info from superolateral part of the arm and skin
What is the median nerve’s responsibility?
Innervate most anterior forearm muscles and several muscles in the palm AND receives sensory info from palmar sides of fingers 1,2,3, and lateral side of finger 4
What nerve is damaged by cruxifiction?
Median nerve which causes the thumb to adduct
What is the musculocutaneous nerve’s function?
Innervates biceps brachii and other anterior arm muscles
What is the radial nerve’s function?
Innervates triceps brachii and several other posterior arm muscles
What is the ulnar nerve’s function?
Innervates some anterior forearm muscles and many muscles of the palm
