a thin stand of pia mater that helps anchor the conus medullaris to the coccyx
define cerival enlargement
in the inferior cervical part of the spinal cord
innervates/control the upper limb
define lumbosacral enlargement
extends through lumbar and sacral part of the spinal cord
innervates/controls lower limbs
what is the difference between gray and white matter region of the spinal cord?
Gray matter: dendrites and cell bodies of neurons; unmyelinated axons and glial cells
White matter: myelinated axon
what are the distributions of gray matter?
what does the anterior horns contain?
house somas of somatic motor neurons
what does the lateral horns contain?
contains cell bodies of autonomic motor neurons; only found in the T1-L2 part of the spinal cord
what does the posterior horns contain?
contains axon of sensory neurons and cell bodies of interneuorons
what does gray commissure contain?
contains unmyelinated axons and serves as communication route between the right and left side
how many spinal nerves does the spinal cord contains? and what are they?
there are 31 spinal nerves:
8 cervical nerves (C1-C8)
12 thoracic nerves (T1-T12)
5 lumbar nerves (L1-L5)
5 sacral nerves (S1-S5)
1 coccygeal nerve (Co1)
where does the spinal nerves exit?
C1-C7 exit the intervertebral foramen above the vertebra of the same number
C8 exit above the first thoracic vertebra
the remaining of cervical spinal nerves exit below the vertebra of the same number
what spinal nerve is responsible for breathing?
C3 and C4
name the major plexuses.
innervates anterior neck muscles and the skin of the neck and head and shoulder
contains phrenic nerve
originated from C4 and contributing axons of C3 and C5
travels through thoracic cavity to innervate the diaphragm
supply the upper limbs
innervates the pectoral girdle and the entire upper limb of one side
*portions of each trunk divided into an anterior and posterior division
formed from the anterior rami of spinal nerves L1-L4
posterior division: femoral nerve
anterior division: obturator nerve
formed from the anterior rami of spinal nerve L4-S4
contains sciatic nerve
the largest and longest nerve in the sacral plexus and in the body
tibial division; common fibular nerve
deep fibular nerve; superficial fibular nerve
autonomic nervous system (ANS) vs somatic nervous system (SNS)
ANS: we have no control over; innervates smooth muscles, cardiac muscles, and glands
SNS: we have control over (voluntary movement); innervates skeletal muscle fibers
preganglionic neuron vs. ganglionic axon
preganglionic neuron: the first neuron in the ANS pathway; its cell body is in the brain or spinal cord
ganglionic neuron: the second neuron in the pathway
preganglionic axon vs. postganglionic axon
preganglionic axon: extends to second cell body housed within an autonomic ganglion in the peripheral nervous system
postganglionic axon: extends from its cell body to effector (target) cells
parasympathetic division: "rest-and-digest"; conserves energy an replenishment of nutrients stores; maintain homeostasis
termed craniosacral division
preganglionic location: brainstem and lateral gray matter of S2-S4
ganglionic location: terminal ganglia (close to target organ), or intramural ganglia (wall of target organ)
sympathetic division: "fight-or-flight"; increases alertness and metabolic activity
preganglionic location: thoracolumbar division (lateral horn in T1-L2)
what cranial nerve is associated with parasympathetic division?
oculomotor (CN III)
facial (CN VII)
glossopharyngeal (CN IX)
vagus (CN X)
what does the glossopharyngeal nerve innervate?
parotid salivary glands
what's CN X relation to ANS?
multiple terminal and intramural ganglia
what is the origin of the sympathetic neuron?
Sympathetic nerves originate inside the vertebral column, toward the middle of the spinal cord in theintermediolateral column (or lateral horn), beginning at the first thoracic vertebra of the spinal cord and are thought to extend to the second or third lumbar vertebra
where does the celiac gangion innervate?
stomach, spleen, liver, gallbladder, proximal duodenum, part of the pancreas
what is the difference between superior and inferior mesenteric ganglion?
superior mesenteric ganglion:preganglionic axons comprised the lesser and least thoracic splanchnic nerve (T10-T12); innervates distal duodenum, part of pancreas, remainder of small intestine, proximal large intestine, kidneys, proximal part of ureters
inferior mesenteric ganglion: comprise the lumbar splanchnic nerves (L1-L2); innervates the distal colon, rectum, urinary bladder, distal ureter, and most of reproductive organs
found in skin or mucous membranes such as nasal and oral cavities and vagina
found in the walls of viscera; detect stretching, oxygen, temperature, and pressure
found in muscles, tendons and joints; detect body and limb movement
detect tissue damage and pain
detect changes in temp
detects pressure changes within body structures
detect changes in light intensity, color, and movement of light
what is the difference between phantom pain and referred pain?
phantom pain: sensation associated with a part of the body that has been removed
referred pain: occurs when impulses from certain viscera are perceived as originating not from the organ but in a dermatome of the skin
what is glaucoma?
a condition of increased pressure within the eyeball, causing gradual loss of sight.
what is the pathway of fluids?
primary neurons extend from gustatory cells of the tongue through paired CN VII and IX, and synapse in the medulla oblongata
secondary neurons travel from the nucleus solitarius and synapse in the thalamus
tertiary neurons travel from the thalamus and terminate in the primary gustatory cortex in the insula of the cerebrum.
name the papillae of the tongue.
what stimulates the 5 taste buds?
our tastes receptors are more sensitive to bitter and sour stimuil