Block 1 Learning Objectives Flashcards
central nervous system
consists of brain and spinal cord
gray matter
collection of neural cell bodies
white matter
axons with glial sheath (myelin)
CNS gray matter and white matter
gray matter- cortex and nucleus
white matter- pathway (tract, vesicle)
peripheral nervous system
neurons outside the CNS, 12 pairs of cranial nerves and 31 pairs of spinal nerves
PNS gray matter and white matter
gray matter- ganglion
white matter- nerve
afferent
approaches CNS, sensory, voluntary, pseudo unipolar neuron
efferent
exits CNS, motor, involuntary, multipolar neuron
somatic tissues
skin, bone, joints, dura, skeletal muscle
visceral tissues
glands, smooth muscle, cardiac muscle
somatic afferent
somatic pain, well localized. sensory. touch, vibration, temp
somatic efferent
volitional movement, motor
visceral afferent
visceral pain, poorly localized, sensory, dissension of organs, unconscious sensations associated with homeostasis
visceral efferent
autonomic NS, motor, modulate glandular secretions and contraction of smooth and cardiac muscle
visceral efferent (ANS) divisions
sympathetic- thoracolumbar NS, fight or flight
parasympathetic- craniosacral NS, rest and digest
enteric- modulated by ANS but functions independently
gray matter- ventral horn
somatic efferent cell bodies
gray matter- lateral horn
visceral efferent cell bodies
gray matter- dorsal horn
central processes of afferent neurons synapse
roots and rootlets
rootlets from one spinal cord segment merge to form a root
dorsal root from dorsal horn
ventral root from ventral horn
spinal nerve
made of one dorsal root and one ventral root that merge to form one spinal nerve
a single pair of spinal nerves represents a single spinal cord segment
rami
spinal nerve branches to form dorsal and ventral rami
dorsal rami supplies
synovial joints of vertebral column, intrinsic back muscles and overlying skin
ventral rami supplies
anterior and lateral regions of trunk and limbs
dorsal root nerve type
afferent only
ventral root nerve type
efferent
plexus
branching network of intersecting nerves
what forms a plexus
ventral rami
types of plexuses
cervical C1-C4
brachial C5-T1
lumbar L1-L4
lumbosacral L4-S4
dermatome
region of skin innervated by somatic afferent fibers of a single spinal nerve
all spinal nerves (except 1) transmit sensory Information from the skin
*where it came from
myotome
muscle mass innervated by somatic efferent fibers of a single nerve, most muscles are innervated by more than one spinal nerve
cutaneous nerves
peripheral nerves to skin
cutaneous territory of a peripheral nerve is region of skin supplied by that nerve
*how it got there
enlargements of the spinal cord
cervical C4-T1– upper limb innervation
lumbar L1-S2– lower limb innervation
conus medullaris
tapered caudal tip
S2-coccygeal spinal cord segments
located at L1/L2 vertebral level
cauda equina
looks like a horse tail
spinal nerve roots from lumbosacral enlargement and conus medullaris
filum terminale
not a nerve
anchors inferior end of spinal cord (tip of conus medularis) to the coccyx
filum terminale internum- from pia
filum terminale externum- from dura
pia mater
delicate, innermost layer
adherent to brain, spinal cord, and nerve roots
denticulate ligaments
formed from pia mater
lateral extension of pia mater, tooth like
attaches pia to arachnoid and dura
provides support for spinal cord
arachnoid mater
delicate, middle layer, looks like spider webs
encloses the subarachnoid space- filled with CSF
arachnoid trabecular connect arachnoid and pia
dura mater
tough, outermost layer
forms dural root sleeve which blend with epineurium
subdural space- potential space btw dura and arachnoid
lumbar cistern
enlargement of subarachnoid space
extends from conus medullaris to end of dura mater and subarachnoid space
contains CSF, cauda equina, and filum terminale internum
location of lumbar punctures- subarachnoid for CSF and epidural space for anesthetic
functions of bone
support, protection, movement of body, storage of minerals and lipids, blood cell production
hyaline cartilage
provides stiff but flexible support
reduces friction between bony surfaces
articular surfaces of joints
elastic cartilage
provides support but tolerates distortion
epiglottis and ear
fibrous cartilage
resists compression
limits relative movement
intervertebral disc
fibrous joint
amount of movement depends on fiber length
sutures of skull and between ulna and radius
*made of fibrous connective tissue
primary cartilaginous joint
permits growth of long bones and allows slight bending
*made of hyaline cartilage
secondary cartilaginous joint
strong, slightly mobile and located at midline of body *contains fibrocartilage and hyaline cartilage
synovial joint
most common, nearly all joints of the limbs, allow significant mobility, synovial fluid lubricates and nourishes
*contains synovial membrane, articular cartilage, and joint capsule
skeletal muscle
voluntary
movement of body, maintenance of posture, communication, respiration, maintenance of body heat
smooth muscle
involuntary
constriction of hallow organs and vessels
arrestor pili- raise hair
cardiac muscle
involuntary contraction of heart
reflexive contraction
autonomic, not voluntarily controlled
tonic contraction
slight contraction assisting stability of joints and maintaining posture
phasic contraction- isometric
muscle length remains the same
phasic contraction- isotonic
muscle length changes to produce movement
concentric- muscle shortens
eccentric- progressive relaxation/lengthening of contracted muscle
prime mover/agonist
main muscle responsible for movement
synergist
complements action of prime mover
antagonist
opposes action of prime mover to produce smooth movement
fixator
fixes position of proximal limb while distal limb moves
subcutaneous tissue/superficial fascia
deep to skin
loose ct- contains fat, cutaneous nerves, and vessels
deep fascia
surrounds all muscles, divides compartments, invests individual muscles and neurovascular bundles
cutaneous nerves
mixed afferent and efferent
preganglionic cell bodies
found in the lateral horn of gray matter
sympathetic preganglionic cell bodies
T1-L2
parasympathetic preganglionic cell bodies
S2-S4
no preganglionic cell bodies
above T1, between L2 and S2, and below S4