Musculoskeletal Flashcards
Major Properties of Muscles
Contractility
Excitably
Extensibility
Elasticity
Contractility
Shorten muscle
Excitability
Muscle response to stimulus
extensibility
Ability to stretch
elasticity
ability to recoil to resting length
Skeletal muscle
Attach to bones
Nuclei are multiple per cell and peripherally located
striated
Important structures of skeletal muscles
Bone, tendon, fascicle, blood vessels, muscle fiber
tendons
fibrous connective tissues that connect to muscle fibers
Muscle anatomy
Origin or head
insertion
belly
Synergists
Separates muscles that work together to cause moment around a joint
agonist
muscles causing a particular action when it contracts
antagonists
muscles working in opposition to agonist, typically relaxes during contraction of agonist
parallel fiber arrangement
longitudinal
pennate fibers arrangement
on an angle
What are the ends od the sarcomere
z lines
Gating
opening and closing of ion channel in response to electrical or chemical signal
Selective Permeability
Allows selective ions to pass through
3 phases of action potential
- depoalrization
- repolarization
- hyperpolarization
depolarization
above the threshold
repolarization
below the threshold, re establishing resting potential
hyperpolarization
after potential
sarcolemma
plasma membrane
t tubules
infoldinfgs in of the scarolemma
sarcoplasmic reticulum
specialized with Ca reservoirs in the cell
Scaroplasmic reticulum Ca ATPase (serca)
ion pump protein that moves Ca from scaroplasm to SR restoring Ca
How can the magnitude of force produce in whole muscle contraction be controled?
motor unit contraction
stimulation
initial length of muscle fibers
graded contractions
produced by variation in number of motor units activated
innervation ratios
vary based functional requirements of muscle
Explain the effect of stimulation to contraction
The force of the contraction can depend on the time of the stimulus and how frequently the stimulus are
Length tension Relationship in an isolated muscle Fiber
Force exerted depends on the number of myson heads engaged in cross bridge cycling with actin filaments
Length tension relationship in a muscle unit including tendons
the passive tendons put the normal active tension to create the Total tension
elastic recoil
the effect of series elastic component of the actively stretched muscle
EX: kangaroo hop
Stretched muscle
ANS signal to contract and shorten muscle
3 types od skeletal fibers
slow oxidative fibers
fast oxidative fibers
fast glycolytic fibers
fast fibers
high myosin ATPase, fatigue rapidly (sprinter)
slow fibers
low myosin ATPase, fatigue slower (long distance runner)
Oxidative fibers
+++ mitochondria
containing myoglobin, increase rate of oxygen in fiber
glycolytic fibers
few mitochondria
can develop more tension
fatigue quickly
Low intensity exercise affect
oxidative fibers
high intensity exercise affect
glycolytic fibers
Fatigue is associated with
ATP depletion and loss of Ca
Increase in muscle mass change
exercise
mechanical stress
SYNTHESIS of myofibrils
Decrease in muscle mass changes
Inactivty
absense of mechanical stress
DEGRATION of proteins
Atrophy
Muscle wasting or loss
Skeletal muscles has a high degree of
plasticity
