The Muscles Flashcards
What are the functions of the muscular system
-movement of the body, maintenance of posture, respiration, production of body heat, communication, constriction of organs and vessels, contraction of the heart
What are the general properties of the muscle?
-contractibility, excitability, extensibility, elasticity
What are the 3 types of muscle tissue?
-cardiac,skeletal, smooth
What is the function of skeletal muscle tissue?
-responsible for locomotion, facial expressions, posture, respiratory movements, other type of body movement
-voluntary
-appears striated (due to thick and thin filaments, cells are multinucleated
What is the function of smooth muscle
-found in bladder, reproductive tracts, gastrointestinal tract, respiratory tract, surrounds blood vessels
-propel urine, mix food in digestive tract, dilating/constricting pupils, regulating blood flow
-in some locations autorhymic
Smooth muscle is controlled involuntarily by the
-endocrine and autonomic nervous systems
Visceral smooth muscle has numerous
-gap junctions (sheets of smooth muscle function as a unit); couple adjacent cells chemically and electrically, facilitating the spread of chemicals or action potentials between smooth muscle cells
What are the function of caridiac muscle
-heart, major source of movement of blood, autorhythmic,controlled involuntarily by endocrine and autonomic nervous system
What are skeletal muscles composed of and what is their appearance
-composed of muscle cells/fibers, connective tissue, blood vessels and nerves
-fibers are long, cylindrical and multinucleated
-striated appearance due to light and dark banding
What is sarcolemma
-plamsa membrane of muscle fiber/cell
What is sarcoplasm
-cytoplasm of muscle cell
What is myofibril
-contractile elements found in muscle cells
Contractibility
ability of a muscle to shorten with force
Excitability
capacity of muscle to respond to a stimulus (from our nerves)
Extensibility
Muscle can be stretched to its normal resting length and beyond to a limited degree
Elasticity
Ability of muscle to recoil to original resting length after stretched
Sarcomere
basic unit of contraction in a myofibiril, region between two z-lines
muscle fiber=
muscle cell
Z-disk
filamentous network of protein. Serves as attachments for actin filaments
I bands
Between thick filaments
A bands
Length of thick filaments
H zone
region in A band where actin and myosin do not overlap
Tropomyosin
An elongated protein that winds along the groove of the actin double helix
Troponin
is found between the ends of the tropomyosin molecules in the groove between actin strands
-composed of three subunits, one that binds to actin, a second that binds to tropomyosin, and a third that binds to calcium ions
The tropomyosin/troponin complex regulates
the interaction between active sites on actin and myosin
Fast aerobic fibers
intermediate size, intermediate strength, some fatigue
-contract relatively quickly and powerfully
-fatigue more quickly than slow fibers
-used in endurance activities
Creatine phosphate
accumulates in muscle tissue, used up quickly
-during resting condition stores energy to synthesize ATP kinase
Anaerobic respiration
occurs in the absence of oxygen and results in breakdown of glucose to yield ATP and Lactic acid
ex. short period of intense exercise(sprint): ATP from creatine phosphate and anaerobic respiration will last about 3 minutes
Aerobic respiration
-more efficient than anaerobic
-requires oxygen and breaks down glucose to produce ATP, CO2, and water
Endurance training
can convert fast muscle fibers from anaerobic to aerobic
Recall: fast anaerobic fatigue more rapidly than fast aerobic fibers
Weight lifting
converts fast muscle fibers from aerobic to anaerobic
Recall: fast anaerobic contract more rapidly and powerfully than fast aerobic fibers
-fatigue more rapidly than fast aerobic fibers, but that’s okay because lifting a weight doesn’t take too long
Isomeric
Muscle is at same length. Muscle can contract, but it only exerts force or tension, and doesn’t shorten. An example would be holding an object up without moving it; the muscular force precisely matches the load, and no movement results
Isotonic
Muscle length changes. Lifting an object at a constant speed is an example of an isotonic contraction. The tension in the muscle remains constant despite a change in muscle length
What are the two types of isotonic contractions
concentric: causes muscles to shorten, thereby generating force
eccentric: cause muscles to elongate in response to a greater opposing force
