Muscles Flashcards
Thousands of parallel _____ join together to form a muscle cell
Myofibril
Muscle cells are also known as
Muscle fibers
The cellular membrane of a muscle cells is known as
Sarcolemma
Muscle fibers join together to form
Fascicles
The muscle organ is formed from what smaller subunit?
Fasicles
Sheath of fibrous elastic tissue surrounding the muscle?
Sheath of connective tissue surrounding a bundle of muscle fibers?
Delicate network of connective tissue which surronds individual muscle fibers.
Epimysium
Perimysium
Endomysium
Myofibrils are divided lengthwise into
Sarcomeres
2 types of myofilament in a sarcomere
Actin & myosin
Which myofilament is thin
Which is thick
Actin is thin
Myosin is thick
Z - lines do what
Seperate sarcomere
This model describes:
During contraction the 2 ends of a sarcomere come closer and the thin filaments slide past the thick ones so actin and myosin overlap more
Sliding filament model
Muscles cells endoplasmic reticlum is called
Sarcoplasmic reticlum
Myosin uses _____ to crawl along actin to produce_____
ATP
Mechanical energy
How many strands is myosin
What kinda enzyme is myosin
2
ATPase
ATP binds to which myosin or actin
Myosin
A motor unit is comprised of
Lower motor neuron
Neuromuscular Junction
Skeletal muscle cell
Fasciculations
Twitches
What is the tone of a muscle?
What is hypotonia
Tone is how much the muscle is contracted when one tries to relax it
Decreased tone in a muscle
When a muscle contracts the bone that moves is called the _________
The bone that doesn’t move is called
Insertion point
Origin
4 functional groups of Skeletal Muscles
Prime Movers
Antagonist
Synergists
Fixators
Muscles mainly responsible for a movement are called
Prime mover
Muscles that move in reverse of a particular movement
Antagonist
Help prime mover muscles by lending a little extra oomph stabilizing joints against dislocation
Synergists
Group of muscle fibers that all get their signals from the same, single motor neuron
Motor unit
3 phases of a muscle twitch
Latent period
Period of contraction
Relaxation Period
Stimulus arrived but no force produced
Latent period
Myosin heads are binding and pulling during this phase of a twitch
Contraction
Myosin and actin stop the binding cycle during this period
Relaxation Period
One muscle can produce a variety of smooth forces called
Graded muscle responses
Muscles increase their force by increasing the ________ with which their neurons are firing
Frequency
Twitches add up to one another as they get closer in time
Temporal summation
A state of sustained contraction in a muscle with out relaxation
Tetanus
Occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize
Action potential
Isotonic vs isometric
Isotonic: Change in length of muscle
Isometric: No change in length of the muscle
Isotonic = Curls, pull ups, squats
Isometric = Plank & Wall sits
The _____ encases individual skeletal muscle fibers
Endomysium
Each muscle is made up of groups of muscle fibers called ______ surrounded by a connective tissue layer called ________
Fascicles
Perimysium
Bundles of skeletal muscle fibers are called
Fasciculli
connective tissue band, called the ________, surrounds several fascicles. A _______ surrounds an individual fascicle.
Epimysium
perimysium
______ connect muscles to bones
Tendons
The cell membrane that surronds muscle fiber is called a ….
Sarcolemma
What is the name of the cytoplasm of a skeletal muscle
Sarcoplasm
One muscle fiber is filled with several long cylindrical proteins called
Myofibrils
The smallest contractile unit in a myofibril is a ….
Sarcomere
Several protein _______ make up a myofibril.
Myofilaments
Sliding Filament Theory:
Actin Filaments slide past _____ filaments. Pulling the Actin Filaments closer to the center of the sarcomere or ___ line
Myosin
M Line
The heads of myosin and actin forming attachments is known as ….
Crossbridges
Muscles work in pairs to move bones at joints. The muscle that causes the joint to bend is called a ______ muscle and the muscle that contracts and causes the muscle to straighten is called an ______ muscle
Flexor
Extension
Which type of muscle has many nucleuses
Skeletal
Which type of muscle has intercalated disc
Cardiac
Why does skeletal muscle have multiple nucli?
Its composed of myoblast during early embryonic development. Each containing their own nucleus
Why is smooth muscle “smooth”
Because Actin and Myosin filaments are not regularly posistioned throughout.
Contractile unit of the muscle
Sarcomere
What is the middle of the sarcomere called
M line
_____ has a long, fibrous tail and a globular head, which binds to ____
Myosin / Actin
Myosin can only bind to actin binding sites are exposed by _______
Calcium ions
Actin is bound to the __ line, which forms the border of the sarcomere
Z line
A _______ is a repeating part within the myofibril of skeletal muscles
Sarcomere
The sarcomere is split into these zones
- ______ consist of myosin only
- _______ consist of actin only
- ______ contains both actin and myosin
- ______ Hold together the thick myosin filaments
- _______ differentiates between each sarcomere.
- H-zone
- I-band
- A-band
- M-line
- Z-line
During contraction of skeletal muscles the ______ stay the same length, but the ______ , ____ ,and _____ decrease in length
A-band
H-zone, I-band, Z-line
_____ is a temporary shift (from negative to positive) in the neuron’s membrane potential caused by ions suddenly flowing in and out of the neuron
Action potential
The _____ filaments slide past the myosin filaments toward the middle of the sarcomere.
The result is shortening of the sarcomere without any change in filament length.
True or False
Actin
True
Myofilaments ( ____ & ____) make up
Myofibrils which make up
_______ aka Muscle Cells which group together to make up
_______ which combine to make up
Muscle Organ “biceps brachi”
Actin & Myosin
Muscle Fibers
Fascicles
The _________ is a delicate network of connective tissue, which surrounds individual muscle fibres
______ surrounds an individual fascicle.
_______ is the dense connective tissue that surrounds the entire muscle tissue.
Endomysium
perimysium
epimysium
The sarcolemma or cell membrane is the site where _____ enters and leaves the cell through a distribution of ion channels, transporters, and pumps.
Calcium
