week 6 muscular system Flashcards
dorsal root and ventral root will form together to form
spinal nerves
How many cranial nerves and how are they separated
12 pairs
CN I olfactory
CN II optic
CN III-XII arise from brainstem
parasympathetic nerve forms plexus with
sympathetic fibers
White rami communicantes
preganglionic fibers, myelianted, leave at thoracolumbar segments of spinal cord
gray rami communicantes
some postganglionic fibers, unmyelinated; leave ganglia to spinal nerves
Gray Vs White matter
in spinal cord gray surrounded by white
in brain white surrounded by gray
splanchnic vs somatic mesoderm
splanchnic is visceral and somatic is limbs
Dorsal primary ramus
(epimere) myoblasts form extensors muscles of vertebral column
ventral primary ramus
(hypomere) myoblasts form flexor muscles (obliques, abdominis)
patterns of muscle and skeletal formation in the limbs is regulated by
connective tissue
how many somites/spinal segments
40 somites, with 6 segments for upper limbs and 6 for lower limbs
ventral primary rami
from each segment enter mesenchyme, branch to form large dorsal and ventral nerves
spinal nerves differentiation and motor innervation
for limb muscles and sensory innervation for dermatomes
Afferent
PNS incoming, sensory
efferent
PNS outgoing, motor
what triggers action potential
sodium
graded potential vs fuse
fuses only move in one direction, graded potential move in all directions
Whats in the dorsal root ganglion
sensory cell bodies
whats in the anterior gray horn
motor cell bodies
sensory cell bodies enter through a
dorsal root
motor cell bodies exit through a
ventral root
Nerves vs tracts
nerves are in PNS
tracts are bundles of axons in CNS
spinothalmic pathway
crude touch, pressure, pair, temperature
posterior column pathway
fine touch, pressure, vibration, proprioception
spinocerebellar pathway
proprioception (below awareness), anterior tracts and posterior tracts
corticospinal pathway
axons from motor cortex of cerebrum to brain stem or spinal cord, conscious, many cross, synapse on lower motor neuron.
medial and lateral pathways
gross movement of trunk/proximal limb (medial), fine movement of distal limb (lateral)
monosynaptic and polysynaptic reflexes provide
rapid involuntary stereotyped responses that maintain homeostasis
Classification of reflexes
development (innate or acquired), type of motor response (visceral, somatic), complexity of neural circuit (monosynaptic or polysynaptic), site of information processing (spinal or cranial)
Innate reflexes
based on genetics, formed at birth
acquired reflexes
rapid, automatic, learned motor patterns
somatic reflexes
immediate (involuntary)
visceral reflexes
autonomic reflexes (control of systems other than muscular)
monosynaptic reflex
simple relex arc
polysynaptic reflex
at least one interneuron between sensory and motor neuron
Neuronal pools
functions groups of interconnected neurons
divergence
stimulation to many neurons or neuronal pools in CNS
convergence
input from many sources to single neuron
serial processing
moves information in single line
parallel processing
same information along several paths simultaneously
reverberation
positive feedback mechanism, functions until inhibited
reflex
automatic response to a stimulus
spinal reflexes
automatic responses coordinated within spinal cord, through interconnected sensory neurons, motor and interneurons.
reflex arc
the wiring of a single reflex, beginning at receptor and ending at peripheral effector
5 steps in a simple neural reflex
- stimulus activates receptor
- activation of sensory neurons
- information processing by postsynaptic cell
- activation of motor neuron
- response of peripheral effector
contralateral reflex arc
motor response occurs on the side opposite to the stimulus; here crossed extensor reflex complements flexor reflex….occur simultaneously using reverberating circuits and positive feedback (leg shifts to one weight)
Cerebellum
coordinates motor patterns
hypothalamus
autonomic centers (heart rate)
thalamus
processing center
cerebrum w/ superficial cortex
conscious thought
3 types of muscle
cardiac, smooth, skeletal
3 layers of muscle connective tissue
epimysium, perimysium, endomysium
muscles have extensive vascular system that
supply large amounts of oxygen, supply nutrients, remove metabolic waste
bundles of fiber
tendon
sheet of fibers
aponeurosis
satellite cells
stem cells
sarcolemma
cell membrane of muscle fiber
sarcoplasm
cytoplasm of muscle fiber
myofibrils
a lot of these, responsible for muscle contraction and then separated into myofilaments
myofilaments
thin (myotin) and thick (myosin)
sacroplasmic recticulum
network sorrounded each myofibril
calcium release ____ and triggers _____
neurotransmitters; muscle contractions
sacromeres
smallest functional unit of muscle fiber
A bands
Dark bands
I bands
light bands
Actin
thin/light
myosin
thick/dark
T Tubules release calcium so
position is important so that all myofilaments get calcium
A band
overlapping thick and thin myofilaments
Myosin is in the center of
sacromere
H band
region of thick myofilaments only
Z lines
boundary between sacromeres
Actinin
protein that helps interconnect thin myofilments of adjacent sacromeres
Titin
elastic protein; helps keep thick and thin myofilaments properly aligned and prevents overstretching of muscle fiber
Sliding filament theory
thin myofilaments slide toward the center of the sarcomere, shortening it
resting membrane potential of skeletal muscle cell
-85 mV
neuron and skeletal muscle fibers are
excitable
voltage gated
channels allow the AP to start in the neuron and release ACh (Na+ is one of them)
chemical gated
channels allow the AP to start in the muscle (chemical because ACh, the neurotransmitter is the chemical that binds to the channel to open it).
Threshold, depolarization and hyper polarization for muscle fibers
-55 threshold
-85 depolarization
beyond -95 hyperpolarization
synaptic cleft
narrow space that separates the axon terminal of the neuron from the opposing motor end plate
AChE
breaks down ACh
muscle cell has ____ inside instead of outside like a neuron
calcium
Ca++ binds to ____ allowing a change in a position
troponin; results in the exposure of the active sites on the thin filaments.
resting sacromere
zone of overlap isn’t fully overlapping to m line
contracting sacromere
zone of overlap nearly reaches m line
Origins and insertions
muscles have one fixed point of attachment (origin)
and one moving point of attachment (insertion)
Agonist
prime mover
Sympathetic
fight or flight, synapse at distance from target, uses NE chemicals, decrease gut activity, increase heart and respiratory rates; affect blood flow and pressure. dilates vessels serving as skeletal muscles. constrict vessel serving as internal organs
parasympathetic
rest and digest. synapse at or near target. uses ACh chemical. increase gut activity, decreases heart and respiratory rates. affect blood flow and pressure. constrict vessels serving skeletal muscles and dilate vessels serving internal organs
quadratus lumborum is a
flexor of the vertebral column
Levator Ani made up of two muscles
Pubococcygeus and Iliococcygeus
external anal sphincter is innervated by
hemorrhoidal branch of pudendal nerve
coccygeus is innervated by
inferior sacral nerves
Urogenital triangle is innervated by the
perineal branch of the pudendal nerve
Pectoral girdle
indirect bony connection to vertebral column.
caudal doral
extensors (deltoid, glutei, wrist, ankle)
caudal ventral
flexors (brachii, hamstrings, wrist, ankle)
cranial dorsal
triceps and quadriceps
cranial ventral
pectorals and adductors
Scapula muscles Posterior
bicep brachii, supraspinatus, infraspinatus, trapezius, teres minor, teres major, rhomboideus minor, rhomboideus major
Scapula muscles Anterior
triceps brachii, pectoralis minor, bicep brachii,
Humerus muscle Anterior
pectorals major, deltoideus, supraspinatus, latissimus doors, teres major and brachialis.
Humerus muscle posterior
teres minor, lateral and medial head of triceps brachii, anconeus,
radius and ulna muscle anterior
brachialis, biceps brachii, interosseous membrane, supinator, pronator quadratus,
radius and ulna posterior muscle
anconeus, supinator
Os Coxa
gluetus maximus, medius and minimus, at top: internal and external oblique, rectus abdominis, adductor: longs, brevis, magnus. Latissimus doors, pectinous, gracilis.
Os Coxa medial view
(inside) iliacus
Femur anterior view
gluteus minimus, vastus lateralis, vastus intermedius,
femur posterior view
gluteus medius, posts major, iliacus, gluteus maximus, adductor: brevis, magnus, and longs.
tibia and fibula posterior view
semimembranosus, soleus
tibia and fibula anterior view
sartorius, peroneus longus, peroneus brevis
trapezius
modified, originally visceral now somatic
trapezius function
movement of scapula and support of head
origin of trapezius
occipital bone, spinous processes of vertebra prominent and thoracic vertebrae
scapular action: protraction and retraction
shoulders shifting to side
scapular action: depression and elevation
depression goes down, elevation goes up
scapular action: downward and upward
shoulder up, shoulder down
Serratus Anterior action
rotation of scapula, protraction of shoulder
Serratus anterior origin
ribs 1-9
Serratus anterior insertion
scapula
Levator Scapulae action
elevates and retracts scapulae, depress glenoid
Rhomboids action
adduction, retract and rotate scapulae, depress glenoid
rhomboids innervation
dorsal scapular nerve
Latissimus Dorsi action
extension, adduction and medial rotation of shoulder opposed by pectoralis
Latissimus Dorsi insertion
humerus
Pectoralis group spans two regions
cranial ventral and caudal ventral quadrants
Pectoralis action
flexion, adduction, and medial rotation at shoulder
Pectoralis Minor is ____ of pectorals major
deep
Pectoralis minor action
depress and protact shoulder, rotation of scapula and stabilizes joint
pectoralis insertion
coracoid process of scapula
Teres Major action
extension, adduction, and medial rotation at shoulders
Teres Minor action
lateral rotation of shoulder
Teres minor innervation
axilary nerve cranial dorsal
Subscapularis action
medial rotation at shoulder
Deltoideus action
abduction at shoulder, flexion and medial rotation, extension and lateral rotation
supraspinatus action
abduction at shoulder
muscles of the rotator cuff
supraspinatus, infraspinatus, subscapularis, teres minor
Triceps brachii action
extension at elbow, adduction at shoulder
biceps brachii action
flexion at elbow, supination
