EXAM 1 Muscular System Flashcards
similarities between muscle cells and action potentials
excitable
Conducts electric impulses by action potentials
Cell membrane is polarized at rest
muscle that is voluntary
skeletal
muscles begin and end with ____.
tendons
individual muscle cells form the _____.
contractile elements
arrangement of muscle fibers between tendons
parallel
muscle cells are rich in _______.
mitochondria
muscle cell’s plasma membrane
sarcolemma
contractile bundles arranged parallel to the muscle cell length
myofibrils
the fundamental contractile unit of a muscle cell
sarcomere
sarcomere consists of 3 things
z disk, thin filaments, thick filaments
thick filament which overlap between thin filaments in sarcomere
myosin
thin filaments (3)
actin, tropomyosin, troponin
lines at the end of sarcomere
z disk
which troponin is not in heart muscle
troponin c
amino acid NT
GABA
Monoamine neurotransmitter
acetylcholine, serotonin, histamine
catecholamine NT
dopamine norepinephrine, epinephrine
system made up of tubular membranes surrounding myofibrils
sarcotubular system
stores and releases calcium in muscle cell
sarcoplasmic reticulum
is sarcolemma myelinated?
no
role of transverse tubules in sarcotubular system
Provide path for the rapid transmission of the action potential from the sarcolemma to the myofibrils
type of proteins that troponin and calmodulin are
binding proteins
what is required for contraction of all muscle typea
calcium
calcium binding protein that skeletal and cardiac muscle use?
troponin
calcium binding protein that smooth muscle uses?
calmodulin
these form the contractile elements in all muscle types
actin and myosin
source of calcium in skeletal muscle
sarcoplasmic reticulum
source of calcium in smooth and cardiac muscle
SR and extracellular fluid via voltage gated Ca++ channels
4 sequential action of skeletal muscle contraction
- cross bridge
- power stroke
- myosin heads unhook
- myosin heads resets
what do myosin heads bind to?
active actin sites
during the power stroke phase, myosin changes shape and does what?
pulls thin actin-tropomyosin strand toward M line
when is ADP released in the action of a skeletal muscle
during the power stroke phase
what must occur to result in recocking of the myosin head
ATP binds to myosin and is cleaved to ADP and Pi
what do you need to repeat the skeletal muscle contraction cycle?
ATP and calcium
in skeletal and cardiac muscle, contraction is inhibited by
tropomyosin–troponin
in smooth muscle, contraction is inhibited by
tropomyosin–calmodulin
why does rigor mortis happen?
death results in the cessation of ATP production, cross bridges become locked in place (muscles stiffen)
ultimate energy source for muscle
ATP
What can replenish ATP for short periods?
creatinine phosphate
when is creatine phosphate most important?
high intensity anaerobic activity
during rest and low intensity activity, what is the primary fuel?
free fatty acids from diet and adipose tissue
primary fuel during strenuous activity?
glucose
in the Cory cycle, what is transferred back to pyruvate and then into glucose?
lactate
the junction between the motor neuron and muscle fiber
motor end plate`
what is a muscle twitch
brief contraction followed by relaxation from a single action potential
fibers specialized for endurance
slow fibers
slow fibers rely mainly on aerobic respiration, which means they prefer ___.
fat
fiber type predominate in posture muscles
slow oxidative. fibers TYPE 1
fiber type predominant in action muscles
fast oxidative fibers type 2A
fibers specialized for quick strong contractions
fast fibers type 2b
fiber predominate in eyes and fingers
fast fibers type 2b
Contraction against a constant load with a reduction in muscle length
Isotonic: Same tension
Force is produced and work IS performed
in what type of muscle contraction?
Isotonic: Same tension
Force is produced but no work is performed
in what type of muscle contraction?
Isometric: Same length
Contraction occurs without a large decrease in the length of the whole muscle
Isometric: Same length
examples of when isometric contraction is used
standing, sitting, posture
contraction that produces movement
Isotonic Contraction
what Is tetany?
sustained involuntary muscle contraction
when tetanic contraction occurs in isolated muscles, it is called _____.
cramping
when does tetanic contraction occur?
Rapid repeated electrical stimulation
causes Repeated activation of contractile mechanism
this results in continuous contraction (tetanus)
Charlie horse is an example of an _____
titanic contraction
example of electrical stimulation causing tetany
stun gun
what are fasiculations
Jerky, visible contractions of small groups of muscle fibers (same as a “twitch”)
Fine, irregular contractions of individual fibers is called______.
fibrillation
What is the calcium-binding protein of the skeletal muscle contractile apparatus?
Troponin
cardiac muscle cells are interconnected by
“intercalated discs”
muscle that Prefers fat as energy substrate
cardiac muscle
when cells function as a unit it is referred to as ____.
Syncytium
muscle cells that Line walls of most hollow organs
smooth
in vascular, smooth muscle regulates ____.
blood flow and pressure
too much bronchial constriction is referred to as __.
asthma
too much arterial and venous dilation is referred to as _____.
septic shock
is smooth muscle striated?
no
The wave-like pattern of pain associated with SM contraction is called
“colicky” pain
