Muscles Flashcards
Study guide
Name and describe the three types of muscle
-Smooth: involuntary, no striations, lines hollow organs
-Cardiac: involuntary, striated
-Skeletal: Voluntary, striated. Attached to Skeleton
What is the fascia
sheet of thick connective tissue surrounding a muscle
What is the epimysium
surrounds all fascicles. wraps entire muscle
What is the perimysium
coarse membrane surrounding fascicles
What is the endomysium
delicate connective tissue sheath around each muscle fiber
Where are myofibrils found? What is their main function?
Found inside muscle fibers; contraction/ relaxation
Name and describe the 2 kinds of protein filaments
Thick: made of protein myosin. Found in dark bands
Thin: made of contractile actin. Found in dark and light bands
What is a sarcomere?
smallest contractile unit of myofibrils
What is the I band
Thin filament
What is the A band?
Thick filament
What is responsible for causing striations in the skeletal muscle?
The light/ dark bands (thick/thin filament pattern)
State the sliding filament theory
Thick filament slide past thin filaments during muscle contraction, while the filaments stay at relatively constant lengths
What enzyme breaks down ATP into ADP releasing energy
ATPase
Neurotransmitters cause skeletal muscle fiber to contract, what is the name of the specific neurotransmitter
Acetylcholine (ACh) found in synaptic vesicles of neuromuscular junctions
What occurs when there is a high concentration of calcium ions present in the sarcoplasm
A cross bridge forms (sliding filament theory)
What are the functions of creatine phosphate and ATP in muscle fibers?
ATP: releases needed energy
Creatine phosphate: transfers a P group to ADP to regenerate ATP
What is myoglobin? Why is it important?
iron and oxygen; binding protein
How does lactic acid affect muscles?
-A lot of glucose used to make only a little ATP
-leads to muscle soreness
Describe rigor mortis
Contraction of muscles a few hours after death due to the release of Ca+ ions
How and why is heat transported throughout the body
muscles generate body heat as a by product of contraction to maintain internal temp
How are muscles named throughout the body (7 ways)
Shape, # of origins, location, size, direction of muscle fibers, action of muscle, origin/ insertion
Define origin
Attachment that remains immobile
Define Insertion
attachment where movement occurs
Define action
type of movement the muscle allows for
What is an all-or-none response? Can skeletal muscles contract partially?
When exposed to a stimulus, muscle fibers will contract to its fullest extent, never partially
-No, but can be a graded response
Define muscle twitch.
Brief contraction followed by relaxation
Describe the three phases recorded during a muscle twitch
-Latent period: time between stimulus and response
-Period of contraction: muscle pulls attachments
-Period of relaxation: muscle returns to former length
What is a tetanic contraction?
When the stimulus increases, there is no relaxation between contractions
Name the 2 processes that produce a sustained contraction
Summation: next twitch occurs before previous twitch relaxes
Recruitment of motor neurons: increase in # of motor units activated as stimulation intensity increases
What is peristalsis? Where does this occur in the body?
Wavelike motion in certain tubular organs and helps force the contents of these organs along their lengths
Ex: intestines, esophagus
