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112 Cards in this Set

  • Front
  • Back
Like nervous tissue, muscles are excitable or "irritable”
they have the ability to respond to a?
Unlike nerves, however, muscles are also?
The main functions of muscles are to?
Create motion, Stabilize body positions and maintain posture, Store substances within the body using sphincters, Move substances by peristaltic contractions, and Generate heat through thermogenesis.
The Three Types of Muscular Tissue are?
Skeletal, Cardiac, and Visceral
(smooth muscle).
What kind of muscle is Striated, multi-nucleated (eccentric), with parallel fibers?
What kind of muscle is striated, with one central nucleus?
What kind of muscle has no striations, and one central nucleus?
(smooth muscle).
What kind of muscle is this
Cardiac Muscle
What kind of muscle is this?
Skeletal muscle
What kind of muscle is this?
Visceral Smooth Muscle
All muscle start as these spindly shaped cells from myoblasts – _____ muscle cells fuse to form large fibers
skeletal muscle
What muscle fibers are very long “cells” - next to neurons (which can be over a meter long), perhaps the longest in the body?
Skeletal Muscle
The _____ muscle contains single fibers that are at least 30 cm long
Sartorious Muscle
The ____, ____ , and ____ all are continuous with the connective tissues that form tendons and ligaments (attach
skeletal muscle to bone) and muscle fascia (connect muscles to other muscles to form groups of muscles)
epimysium, perimysium, and endomysium
The vein like structure in this image is called the ____ while the membrane surrounding the muscle fibers is called the ____.
Motor Neuron, Sarcolemma
This picture show the organization of a?
Organization of a fasciculus
This pirture show the Organization of a?
Organization of a muscle fiber
This pic shows A muscle, a fasciculus, and a ____ all visualized
This graphic shows the ____ ____ enveloping the entire group of quadriceps and hamstring muscles in the thing
fascia lata
This pic shows Many large muscle groups are encased in both a ____ and a ____ fascia
Superficial , and Deep Fascia
An aponeurosis is
essentially a thick
fascia that connects two muscle bellies. This epicranial aponeurosis connects the muscle bellies of the occipitalis and the frontalis to form “one” muscle: The?
Veins, arteries, and nerves are located in the deep fascia between muscles of the?
The ____ of skeletal muscle fibers is chocked full of contractile proteins arranged in myofibrils
cytoplasm (sarcoplasm)
List the 7 names of the internal structures of the muscle fiber.
Triad (with terminal cisterns
Sarcoplasmic reticulum Sarcomere
Study this pic for the internal structures of the muscle fiber
reference only
Increasing the level of magnification, the myofibrils are seen to be composed
of filaments Thick filaments and thin Thin filaments
Study Pic
Reference only
What are multi-protein complexes composed of three different filament systems?
The thick filament system is composed of ____ protein which is connected from the M-line to the Z-disc by titin.
The thick filament system is composed of myosin protein which is connected from the M-line to the Z-disc by titin. It also contains myosin-binding protein C which binds at one end to the thick filament and the other to?
The thin filaments are assembled by actin monomers bound to nebulin, which also involves tropomyosin (a dimer which coils itself around the F-actin core of the thin filament) and?
Nebulin and titin give stability and structure to the?
The basic functional unit of skeletal muscle fibers is the sarcomere: An arrangement of thick and thin filaments sandwiched between two?
Z discs
Myofibrils are built from what three groups of proteins?
Contractile proteins, Regulatory proteins, and Structural proteins
What proteins generate force during contraction?
What proteins help switch the contraction process on and off?
What proteins keep the thick and thin filaments in proper alignment and link the myofibrils to the sarcolemma and extracellular matrix?
The thin filaments are comprised mostly of the structural protein ____, and the thick filaments are comprised mostly of the structural protein ____?
actin, and myosin
In the thin filaments actin proteins are strung together like a bead of?
In this graphic, the____ ____ sites on the actin proteins are readily visible.
myosin binding sites
The regulatory proteins troponin and tropomyosin have been added to this graphic: The myosin binding sites have been covered. Study pic
Reference only
In this graphic the troponin-tropomyosin complex has slid down into the “gutters” of the actin molecule unblocking the ____ ____ site
myosin binding site
The troponin-tropomyosin complex can slide back and forth depending on the presence of?
What binds to troponin which changes the shape of the troponin-tropomyosin complex and uncovers the myosin binding sites on actin?
What is the third most plentiful protein in muscle, after actin and myosin - it extends from the Z disc and accounts for much of the elasticity of myofibrils?
What relates to the disease of muscular dystrophy?
Titin is the largest known protein, consisting of 34,350 ____ ____. Titin, also known as connectin is a protein that is important in the contraction of striated muscle tissues.
amino acids
With exposure of the myosin binding sites on actin (the thin filaments)—in the presence of Ca2+ and ATP—the thick and thin filaments “slide” on one another and the ____ is shortened.
The “sliding” of actin on myosin (thick filaments on thin filaments) can be broken down into what 4 step process?
Step 1: ATP hydrolysis
Step 2: Attachment
Step 3: Power Stroke
Step 4: Detachment
This step is called?
Step 1 ATP hydrolysis
This step is called?
Step 2: Attachment
This step is called
Step 3: Power Stroke
This step is called?
Step 4: Detachment
The Sliding-Filament Mechanism.
Study pic
Reference Only
Sarcomere shortening produces ____ within a muscle
What involves events at the junction between a motor neuron and a skeletal muscle fiber.
Excitation-Contraction coupling (EC coupling)
What involves events at the junction between a motor neuron and a skeletal muscle fiber.
Excitation-Contraction coupling (EC coupling)
The presynaptic membrane is on the neuron while the postsynaptic membrane is the ____ ____ ____ on the muscle cell. The two membranes are
separated by a space, or “cleft”
motor end plate
Conscious thought (to move a muscle) results in activation of a motor neuron, and release of the neurotransmitter ____ at the NM junction
acetylcholine (AcCh)
The enzyme acetylcholinesterase
breaks down ____ after a short period
of time
acetylcholine (AcCh)
The plasma membrane on the “far side” of the Neuromuscular Junction belongs to the muscle cell and is called the ____ ____ ___.
motor end plate
The receptors for AcCh are on the ____-____ ___ channels on the motor end plate
ligand-gated sodium channels
Na+ gates open during the
depolarization phase K+ gates open during the?
repolarization phase
Generating an AP on the muscle membrane involves the transfer of information from an ____ signal (down the neuron), to a _____ signal (at the NMJ), back to an ____ signal (depolarization of the sarcolemma).
electrical, chemical, electrical
The added complexity of a muscle action potentional (changing from electrical to chemical back to electrical signals) provides necessary ____ of the process
Excitation-Contraction Coupling Study pic
Excitation-Contraction Coupling
Describe Excitation-Contraction Coupling.
The thought process going on in the brain
The AP arriving at the neuromuscular junction
The regeneration of an AP on the muscle membrane
Release of Ca2+ from the sarcoplasmic reticulum
Sliding of thick on thin filaments in sarcomeres
Generation of muscle tension (work)
Excitation-Contraction Coupling study pic
Excitation-Contraction Coupling
Sources of Muscle Energy are?
Stored ATP
Energy transferred from stored creatine phosphate
Aerobic ATP production
Anaerobic glucose use
Stored ATP give about ___ seconds of energy.
Energy transferred from stored creatine phosphate give about ____seconds of energy
Anaerobic glucose use give about ____ seconds of energy
Sources of Muscle Energy
Sources of Muscle Energy
In a state of homeostasis, muscle use of O2 and nutrients is balanced by the production of manageable levels of waste products like?
CO2, Heat, and Lactic acid (anaerobic)
70-80% of the energy used by muscles is lost as?
Oxygen Debt, or "Excess Post-Exercise Oxygen Consumption" (EPOC) is the amount of O2 repayment required after exercise in skeletal muscle to?
Replenish ATP stores
Replenish creatine phosphate and myoglobin stores
Convert lactic acid back into pyruvate so it can be used in the Krebs cycle to replenish ATP
In response to a single AP, cardiac muscle contracts 10-15 times longer than ____ muscle, and must continue to do so, without rest, for the life of the individual
To meet the constant demand, cardiac muscle generally uses the rich supply of O2 delivered by the extensive ____ circulation to generate ATP through aerobic respiration
Like cardiac muscle, smooth muscle (in your deep organs) is ____ and is not under voluntary control
Unlike cardiac (and skeletal muscle) however, smooth muscle has a low capacity for generating ATP and does so only through?
anaerobic respiration (glycolysis)
Motor Unit is composed of a motor neuron plus?
all of the muscle cells it innervates
A High precision motor unit has?
Fewer muscle fibers per neuron
Laryngeal and extraocular muscles (2-20)
A Low precision motor unit has?
Many muscle fibers per neuron like the Thigh muscles (2,000-3,000)
Activities requiring extreme precision (like the subtle and rapid movements of the eye) involve muscles with?
very small motor units (1-4 muscle fibers/neuron)
Describe the All-or-none principle of muscle contraction.
When an individual muscle fiber is stimulated to depolarization, and an action potential is propagated along its sarcolemma, it must contract to it’s full force—it can’t partially contract
When a single motor unit is recruited to contract, all the muscle fibers in that motor unit must?
all contract at the same time
Red muscle fibers (the dark meat in chicken legs) have a high myoglobin content, and?
more mitochondria, more energy stores, and a greater blood supply
White muscle fibers (the white meat in chicken breasts) when compared to red muscle fibers, have less?
myoglobin, mitochondria, and blood supply
Slow oxidative fibers (SO) are small, appear dark red, are
the least powerful type. They are very?
fatigue resistant
Fast oxidative-glycolytic fibers (FOG) are intermediate in
size, appear dark red, and are moderately resistant to fatigue. They are used for?
Fast glycolytic fibers (FG) are large, white, and powerful
Suited for?
intense anaerobic activity of short duration
Within a particular motor unit all the skeletal muscle fibers are?
the same type
The different motor units in a muscle are recruited in a specific order depending on the?
task being performed (fast anaerobic activity for maximal force, etc.)
There is a brief delay called the ____ ____ as the AP sweeps over the sarcolemma and Ca2+ ions are released from the sarcoplasmic reticulum (SR).
latent period
After the latent periord the next phase is?
the fiber is actively contracting
The contracting phase is followed by relaxation as the Ca2+ ions are re-sequestered into the SR and myosin binding sites are covered by?
Temporary loss of excitability is call the ____ ____. All muscle fibers in a motor unit will not respond to a stimulus during this short time
refractory period
A ____ is recorded when a stimulus that results in contraction (force) of a single muscle fiber is measured over a very brief millisecond time frame.
Tension in a Muscle
Tension in a Muscle
Two motor units, one in green, the other in purple, demonstrate the concept of progressive activation of a muscle known as?
What is a type of muscle contraction in which the muscle shorten while generating force?
Concentric isotonic
What is a contraction in which muscle tension is less than the resistance (the muscle lengthens)?
Eccentric isotonic
What contractions results in no movement?
Muscle force and resistance are equal Example:
Supporting objects in a fixed position and posture
Muscle Contraction
Muscle Contraction
After intense exercise electron micrographs reveal considerable muscle damage including?
torn sarcolemmas and disrupted Z-discs
Blood levels of proteins normally confined only to muscle (including myoglobin and the enzyme creatine kinase) ____ as they are released from damaged muscle
What is A sudden involuntary contraction of a single muscle within a large group of muscles?
Involuntary and often painful muscle contractions
Caused by inadequate blood flow to muscles (such as in dehydration), overuse and injury, and abnormal blood electrolyte levels. This is called a?
Replacement of muscle fibers by excessive amounts of connective tissues is called?
Fibrosis (myofibrosis)
Hardening of the muscle caused by calcification is called?
Both myosclerosis and muscle fibrosis occur as a result of?
trauma and various metabolic disorders
In part due to decreased levels of physical activity, with aging humans undergo a slow, progressive loss of skeletal muscle mass that is replaced largely by?
fibrous connective tissue and adipose tissue
Muscle strength at 85 is about half that at age 25
Compared to the other two fiber types, the relative number of slow oxidative fibers appears to?