Flashcards in Muscle Physiology Deck (67):
How are muscle cells excitable?
What are the 3 types of muscles?
Similarities between muscle cells and neurons
- conducts electrical impulses by action potentials
- cell membrane is polarized at rest while membranes are at resting potential
Characteristics of skeletal muscle
- multinucleated fibers
Muscles ______ and ______ with ________.
Muscles BEGIN and END with TENDONS.
Individual ______ ______ form the __________ ______ in skeletal muscle.
Individual MUSCLE CELLS (FIBERS) form the CONTRACTILE ELEMENTS in skeletal muscle.
_________ __________ of muscle fibers between ______ with the _______ of the tendon.
PARALLEL ARRANGEMENT of muscle fibers between TENDONS with the DIRECTION of the tendon.
The _____ of individual muscle fibers contracting is ________. More _____ = more ______.
The FORCE of individual muscle fibers contracting is ADDITIVE. More FIBERS = more FORCE.
Muscle cells are ________, long, ________ cells that are rich is ___________.
Muscle cells are MULTINUCLEATED, long, CYLINDRICAL cells that are rich in MITOCHONDRIA.
________ is the cell's plasma membrane.
SARCOLEMMA is the cell's plasma membrane.
Muscle cells are filled with ________ arranged ______ to the cell length.
Muscle cells are filled with MYOFIBRILS (CONTRACTILE BUNDLES) arranged PARALLEL to the cell length.
The _______ is the _________ _______ _____ of skeletal muscle.
The SARCOMERE is the FUNDAMENTAL CONTRACTILE UNIT of skeletal muscle.
The sarcomere consists of:
1. Z disk
2. thin filaments
3. thick filaments
Z lines are at the ____ of sarcomere and are composed of _______, which is a _______ _______.
Z lines are at the ENDS of sarcomere and are composed of ALPHA-ACTININ, which is a CYTOSKELETAL PROTEIN.
_____ filaments project from the Z disk to the ______ of the sarcomere. They contain _____, _______, and _________.
THIN filaments which project from the Z disk to the CENTER of the sarcomere. They contain ACTIN, TROPOMYOSIN, and TROPONIN.
_______ filaments overlap between _____ filaments. They contain ______.
THICK filaments overlap between THIN filaments. They contain MYOSIN.
The ______ heads of _____ interact with the _____ _____ filaments.
The GLOBULAR heads of MYOSIN interact with the THIN ACTIN filaments.
____ thick filaments reverse _______ at the ___ line.
MYOSIN thick filaments reverse POLARITY at the M line.
___ lines are pulled ________ during contraction.
Z lines are pulled TOGETHER during contraction.
amino acid neurotransmitters
aminobutyric acid (GABA)
_______ system is made up of _______ membranes surrounding _______.
SARCOTUBULAR system is made up of TUBULAR membranes surrounding MYOFIBRILS.
_______ tubules are continuous with the _______, which is the ______ __________. They provide a path for the rapid _________ of the ______ ________ from the ________ to the __________.
TRANSVERSE tubules are continuous with the SARCOLEMMA, which is the PLASMA MEMBRANE. They provide a path for the rapid TRANSMISSION of the ACTION POTENTIAL from the SARCOLEMMA to the MYOFIBRILS.
The _____ ______ stores and releases _____.
The SARCOPLASMIC RETICULUM stores and releases Ca++.
______ is required for __________ of ____ muscle types. ______ and _____ form the _____ elements in ___ muscle types.
CALCIUM is required for CONTRACTION of ALL muscle types. ACTIN and MYOSIN form the CONTRACTILE elements is ALL muscle types.
_____-binding _____ differ among muscle types to trigger process of _________.
CALCIUM-binding PROTEINS differ among muscle types to trigger process of CONTRACTION.
______ and ______ muscles use ______ as their calcium-binding proteins. ______ muscle uses _______ as their calcium-binding proteins.
SKELETAL and CARDIAC muscles use TROPONIN as their calcium-binding proteins. SMOOTH muscle uses CALMODULIN as their calcium-binding proteins.
Skeletal muscle's source of calcium is from the _____ _____ ONLY. Cardiac and smooth muscle's source of calcium is from the ______ _________ and _________ ______.
Skeletal muscle's source of calcium is from the SARCOPLASMIC RETICULUM ONLY. Cardiac and smooth muscle's source of calcium is from the SARCOPLASMIC RETICULUM and EXTRACELLULAR FLUID.
1st action of skeletal muscle contraction: _____-______ formed between _____ and _______.
1st action of skeletal muscle contraction: CROSS-BRIDGE formed between ACTIN and MYOSIN.
2nd action of skeletal muscle contraction: ____ _______ with ______ heads pulls ______.
2nd action of skeletal muscle contraction: POWER STROKE with MYOSIN heads pulls ACTIN.
3rd action of skeletal muscle contraction: ______ heads ______ from _____ ______ sites.
3rd action of skeletal muscle contraction: MYOSIN heads UNHOOK from ACTIN ACTIVE sites.
4th action of skeletal muscle contraction: Myosin heads _____ to prepare for the next __________.
4th action of skeletal muscle contraction: Myosin heads RESET to prepare for the next CONTRACTION.
In relaxed skeletal muscle, contraction is ______ by ______-______, which _____ the ____ active site and free cytoplasmic _______ is pumped back into the _________ ________.
In relaxed skeletal muscle, contraction is INHIBITED by TROPOMYOSIN-TROPONIN, which BLOCK the ACTIN active site and free cytoplasmic CALCIUM is pumped back into the SARCOPLASMIC RETICULUM.
_____ ______ occurs due to the lack in ____ after ______ to unhook the cross-bridges between _____ from ____ and they become locked in place.
RIGOR MORTIS occurs due to the lack in ATP after DEATH to unhook the cross-bridges between MYOSIN from ACTIN and they become locked in place.
____ is the ultimate energy source, which is formed during _____ and ____ metabolism through ______ ___________.
ATP is the ultimate energy source, which is formed during CARBOHYDRATE and LIPID metabolism through OXIDATIVE METABOLISM.
______ ________ can replenish ATP for ____ periods and most important during ____ intensity ________ activity.
CREATININE PHOSPHATE can replenish ATP for SHORT periods and most important during HIGH intensity ANAEROBIC activity.
Creatine is __________ to creatine ________ with ____ when ___ is available. ________ phosphate donates __ to ____ via _____ _______.
Creatine is REPHOSPHORYLATED to creatine PHOSPHATE with ATP when O2 is available. CREATINE phosphate donates P to ADP via CREATINE KINASE.
During rest and ____-intensity activity, the primary fuel is ____ _____ _____ from diet and adipose tissue.
During rest and LOW-intensity activity, the primary fuel is FREE FATTY ACIDS from diet and adipose tissue.
During _____ activity, the primary fuel is _____ from diet, ________, or __________.
During STRENUOUS activity, the primary fuel is GLUCOSE from diet, GLUCONEOGENESIS, or GLYCOGENOLYSIS.
In _______ conditions, ______ is converted to ______, which is then metabolized by the ____ back to _____ via ___________. This process is know as the ______ ______.
In ANAEROBIC conditions, PYRUVATE is converted to LACTATE, which is then metabolized by the LIVER back to GLUCOSE via GLUCONEOGENESIS. This process is know as the CORI CYCLE.
Muscle fiber membrane __________ normally starts at the _____ ____ _____, the junction between the motor _____ and the muscle _____.
Muscle fiber membrane DEPOLARIZATION normally starts at the MOTOR END PLATE, the junction between the motor NEURON and the muscle FIBER.
_________ releases from the _____ neuron and binds to ____ ________ on motor end _____ and initiates the muscle _____ ________.
ACETYLCHOLINE releases from the MOTOR neuron and binds to ACH RECEPTORS on the motor end PLATE and initiates the muscle ACTION POTENTIAL.
The _____ _______ is transmitted along the ______ to the ___ ______, initiating the contractile response via ______ release from the _________ _______.
The ACTION POTENTIAL is transmitted along the SARCOLEMMA to the T TUBULE, initiating the contractile response via CALCIUM release from the SARCOPLASMIC RETICULUM.
A ______ ______ is a brief ________ followed by ________ resulting from a ______ action potential. Twitch _____ varies with muscle _____ type.
A MUSCLE TWITCH is a brief CONTRACTION followed by RELAXATION resulting from a SINGLE action potential. Twitch DURATION varies with muscle FIBER type.
_____ fibers are specialized for endurance. “____” muscle = much more _______ and ____ glycogen. They rely mainly on ______ respiration (i.e., prefer ____). Predominate in ______ muscles, around ______. Slow but efficient, ______ resistant. Abundant ______ supply, high _______ content.
SLOW fibers are specialized for endurance. “RED” muscle = much more MITOCHONDRIA and LESS glycogen. They rely mainly on AEROBIC respiration (i.e., prefer FAT). Predominate in POSTURAL muscles, around JOINTS. Slow but efficient, FATIGUE resistant. Abundant CAPILLARY supply, high MYOGLOBIN content.
Slow fibers are predominate in ______ muscles and around _____. They are slow but ____ and _____ resistant. They have abundant ______ supply and high ______ content.
Slow fibers are predominate in POSTURAL muscles and around JOINTS. They are slow but EFFICIENT and FATIGUE resistant. They have abundant CAPILLARY supply and high MYOGLOBIN content.
_____ oxidative (Type 2_) fibers are predominate in ____ muscles. They are _____ fast and moderately ______ resistant. They have _______ capillary supply and myoglobin content
FAST oxidative (Type 2A) fibers are predominate in ACTION muscles. They are MODERATELY fast and moderately FATIGUE resistant. They have MODERATE capillary supply and myoglobin content
Fast oxidative (Type 2_) are referred to as “_____” muscle. They rely mainly on _______ respiration, ______, ____ glycogen content. They control ____, rapid, _____ movements. They are predominate in muscles of ____ and fingers, _____, lips. They have a _____ response but ____ fatigue (produce lactate). They produce ____, _______ contractions.
Fast oxidative (Type 2B) are referred to as “WHITE” muscle. They rely mainly on ANAEROBIC respiration, GLYCOLYSIS, HIGH glycogen content. They control FINE, rapid, PRECISE movements. They are predominate in muscles of EYES and fingers, TONGUE, lips. They have a FAST response but QUICKLY fatigue (produce lactate). They produce BRIEF, POWERFUL contractions.
Skeletal muscle fibers are arranged into “_____ _____” of multiple _____ (muscle cells) within a muscle activated by ____ motor neuron.
Skeletal muscle fibers are arranged into “MOTOR UNITS” of multiple MYOCYTES (muscle cells) within a muscle activated by ONE motor neuron.
Motor units are recruited ________ as the more force is needed. Small ratios of myocytes to a neuron results in ____ motor control but ___ strength, ____ ratio results in high strength but ____ motor control.
Motor units are recruited SEQUENTIALLY as the more force is needed. Small ratios of myocytes to a neuron results in FINE motor control but LOW strength, HIGH ratio results in high strength but LESS motor control.
_______ contraction = _____ tension
ISOTONIC contraction = SAME tension
Isotonic contractions are against a _______ load with a ________ in muscle length. Force is produced and _____ is performed.
Isotonic contractions are against a CONSTANT load with a REDUCTION in muscle length. Force is produced and WORK is performed.
________ contractions = _____ length
ISOMETRIC contractions = SAME length
Isometric contractions: Force is produced but ___ ______ is performed. _____ is the predominant energy source. They are used in _____, ______, and ______.
Isometric contractions: Force is produced but NO WORK is performed. FAT is the predominant energy source. They are used in STANDING, SITTING, and POSTURE.
______ is _______ sustained ________ muscle contraction. It is caused by ______ repeated _______ stimulation and results in ________ contraction. May affect _____ muscles or ____ muscles.
TETANY is UNCONTROLLED sustained INVOLUNTARY muscle contraction. It is caused by RAPID repeated ELECTRICAL stimulation and results in CONTINUOUS contraction. May affect ISOLATED muscles or ALL muscles.
_________ are _____, visible __________ of _____ groups of muscle fibers (same as a “_____”).
FASICULATIONS are JERKY, visible CONTRACTIONS of SMALL groups of muscle fibers (same as a “TWITCH”).
_______ are fine, ________ contractions of __________ fibers. They are usually not grossly _____.
FIBRILLATIONS are fine, IRREGULAR contractions of INDIVIDUAL fibers. They are usually not grossly VISIBLE.
_______ muscle are a _______ of individual _____, _____ muscle cells (cardiomyocytes) linked by ___ _______ communication. The _____ _______ travels through all cells
CARDIAC muscle are a COLLECTION of individual BRANCHING, STRIATED muscle cells (cardiomyocytes) linked by GAP JUNCTION communication.
Cardiac muscle cell are interconnected by _________ _____ forming a functional ________ and contract as a ______. They are ______ muscle and prefer ____ as the energy substrate.
Cardiac muscle cell are interconnected by INTERCALATED DISCS forming a functional SYNCYTIUM and contract as a UNIT. They are INVOLUNTARY muscle and prefer FAT as the energy substrate.
______ muscle lines the walls of most ______ organs, i.e. ______ vessels, ___ tract, and uterus. Too _____ or too much smooth muscle _____ can interrupt ____________.
SMOOTH muscle lines the walls of most HOLLOW organs, i.e. BLOOD vessels, GI tract, and uterus. Too LITTLE or too much smooth muscle TONE can interrupt HOMEOSTASIS.
Smooth muscle is _______ (spindle shaped) and _____nucleated. It is _____striated and involuntary.
Smooth muscle is FUSIFORM (spindle shaped) and MONOnucleated. It is NONstriated and involuntary.
The slow, ____-like pattern of _____ associated with SM contraction is called “______” pain.
The slow, WAVE-like pattern of PAIN associated with SM contraction is called “COLICKY” pain.
2. Power Stroke: _____ changes shape, pulling thin ______-________ strand toward the ___ line. This releases _____ and ____.
Power Stroke: MYOSIN changes shape, pulling thin ACTIN-TROPOMYOSIN strand toward the M line. This releases ADP and Pi.
3. Unhook: _____ binds to _____ head causing _____ head to _____ from actin active site by changing configuration of the ______ strand.
Unhook: ATP binds to MYOSIN head causing MYOSIN head to UNHOOK from actin active site by changing CONFIGURATION of the myosin strand.
4. Recooking: ____ binds to ____ and is cleaved to ____ and __, resulting in _____ of the ______ head. Myosin head is ready to attach to another _____ active site. This requires ____ and ___ to repeat the cycle!
4. Recooking: ATP binds to MYOSIN and is cleaved to ADP and Pi, resulting in RECOCKING of the MYOSIN head. Myosin head is ready to attach to another ACTIN active site. This requires ATP and CA++ to repeat the cycle!