Muscular System Flashcards
function of muscular system (4)
movement
stabilization of body position
organ volume regulation
thermogenesis
three types of muscle tissues
skeletal muscle
cardiac muscle
smooth muscle
cell membrane of a muscle cell
sarcolemma
cytoplasm of a muscle cell
sarcoplasm
functional unit of a skeletal muscle
sarcomere
outermost covering of a muscle
epimysium
bundle of muscles
fascicle
covers the fasciculi
perimysium
myo means
fibers
one fascicle is made up of these
myofibers
bundle of thin and thick filaments
myofibril
thick filaments
myosin
thin filaments
actin
each head has a ATP binding site and actin-binding site
myosin head
myosin protein is made up of
myosin tail
myosin head
circle-shaped in thin filaments, most numerous out of the proteins in thin filament
actin proteins
rope-like structure in thin filaments
tropomyosin
round-like structures in thin filaments
troponin
red, attaches to the second protein, the tropomyosin
troponin T (TnT)
violet
troponin C (TnC)
blue
troponin I (TnI)
binds to the troponin C, abundant in bones
calcium
exposed after calcium binds to troponin C
myosin-binding site
said to be regulatory since when the calcium is bound to the said complex, it exposes the myosin-binding sites in actin filaments
troponin-tropomyosin complex
boundary of a sarcomere
z-line
light bond, I means “isotropic” contains thin filaments
I bond
dark bond, A means “anisotropic”, contains both thin and thick filaments
a bond
contains the thick filaments
H zone
bisects the A bond and connects the thick filaments together
M zone
Two tubular systems associated with a sarcomere
transverse tubule
sarcoplasmic reticulum
at right angle to the sarcolemma
transverse tubule
just like the ER, but found within the muscle
sarcoplasmic reticulum
Stores the calcium ions
Sarcoplasmic reticulum
composes the triad along with the transverse tubule
terminal cisternae
association of one transverse tubule and two terminal cisternae of two adjacent sarcoplasmic reticulum
triad
three types of neurons
sensory
association
motor
neuron associated with a muscle
motor neuron
senses motor impulses from CNS to the muscle which results in contraction
motor neuron
communication between a motor neuron and the muscle
NMJ (neuromuscular junction)
axon further divides into these
axon terminals
end of the muscle
motor end plate
end of the muscle
motor end plate
end of the muscle
motor end plate
gap between the motor neuron and motor-end plate of a muscle
synaptic cleft
gap between the motor neuron and motor-end plate of a muscle
synaptic cleft
needed for muscle contraction
nerve impulses
opens when nerve impulses arrive
calcium channels
causes the release of neurotransmitters inside the synaptic vesicles
influx of calcium ions
contain acetylcholine (ACh)
synaptic vesicles
neurotransmitter that transmits the impulses from the motor neuron to the muscle
acetylcholine
its charge (outside + charge, inside – charge)
resting membrane potential
what happens to the membrane when the positive charged ions enter the inside of the muscle
depolarization
enters the muscle cell
sodium ion
where the impulse travels after depolarization
T tubule
when impusles arrive
calcium release channels
released after impulses opens the calcium release channels
calcium
provide the force essential for movement in all animals
muscles
use their endoskeleton in conjunction with muscles to move
vertebrates
usually elicited in response to the information provided by the central nervous system (CNS)
movement
in vertebrates, these move the body
striated skeletal muscles
move materials through tubular organs and change the size of tubular openings
smooth muscles
produces the beating of the heart
cardiac muscle
three pincipal kinds of animal movement
amoeboid movement
ciliary and flagellar movement
muscular movement
exhibited by amoebas, many wandering cells of higher animals (white blood cells and embryonic mesenchyme)
amoeboid movement
change their shape by sending out and withdrawing pseudopodia from any point on the cell surface
amoeboid cells
exhibited by protozoans and all major groups of animals, except nematodes and arthropods
ciliary movement
responsible for moving small animals such as protozoa through their aquatic habitat or in propelling fluids and materials across the epithelial surface of larger animals
cilia
Lines respiratory airways and prevent contaminants trapped in the mucus from reaching the lungs by sweeping mucus towards the throat
cilia
sweeping action of ciliated cells lining the female reproductive tract facilitates the conduction of these towards the oviducts and eventually to the uterus
egg cell
exhibited by flagellated protozoa, animal spermatozoa, and sponges
flagellar movement
whip-like structure longer than a cilium and usually present in singly or in small numbers at one end of a cell
flagellum
are structurally the same and only differ in their beating pattern
cilia and flagella
beats symmetrically with snake-like undulation
flagellum
Water is propelled parallel to the long axis of this
flagellum
beats asymmetrically with a fast power stroke in one direction followed by a slow recovery during which the it
bends as it returns to its original position
cilium
in these, the water is propelled parallel to the ciliated surface
cilium
brought about by the contraction of muscle cells or fibers;
muscular movement
muscle fibers do this as they contract
shorten
exhibited by the rest of the members of the animal kingdom
muscular movement
type of invertebrate muscle
bivalve molluscan muscles
insect flight muscle
capable of rapid contraction due to the presence of sliding thin and thick filaments, which aid the invertebrate to snap shut it valves when under stressed or disturbed condition
striated muscles
capable of slow yet long-lasting contraction, due to the intermediate filaments
smooth muscles
aid the invertebrate to keep it valves tightly shut for hours or even days
intermediate filaments
fibrillar muscle contracts at frequencies greater than 1,000 beats per second
insect flight muscle
named this because it is attached to the skeleton and makes possible the movement of trunk; and other obdy parts
skeletal muscle
consists skeletal muscles, which are large, striated, cylindrical and multinucleated cells that develop through the fusion of many individual cells
muscle fibers
muscle fibers bundled together by a connective tissue
fascicle
where most skeletal muscles taper, where they connect to bones by tendons
ends
contract powerfully and quickly but fatigue more quickly than does smooth muscle
skeletal muscles
skeletal muscles are also called this because they are stimulated by motor fibers and are under conscious cerebral control
voluntary muscles
also called heart muscle, is striated, uninucleated, and is composed of branching cell fibers that give cardiac muscle an ability to resist tearing, making heart walls tolerant of high pressures
cardiac muscle
provides strong mechanical adhesions between adjacent cardiac muscle cells, contains gap junctions for rapid conduction of impulses
intercalated disk
are tissues that cardiac muscle share characteristics with
skeletal and smooth
characteristics of skeletal muscle that cardiac muscle shares
fast acting and striated
characteristics of smooth muscle that cardiac muscle shares
involuntary
specialized cardiac muscle cells that enables muscle contraction
pacemaker cells
Initiate the rhythmic contractions of the heart
pacemaker cells
non-striated with long, tapering single-nucleated cells that are found encircling the walls of hollow, internal organs
smooth muscle
in smooth muscles, are not obvious when cells are viewed under light microscope since filaments of actin and myosin are not as regularly arranged unliked in striated muscle type
contractile machinery
primary function of smooth muscle
movement of material
peristalsis
sustained contraction
series of wave-like muscle contractions that move food through the digestive tract
peristalsis
regulation of the opening of certain organs (e.g. arteries)
sustained contraction
usually slow acting and can maintain prolonged contractions with very little energy expenditure
smooth muscle
controls the smooth muscle, thus its contractions are involuntary and unconscious
autonomic nervous system
function of muscles that rely on the integrative functioning of bones, joints and skeletal muscles
movement
function of muscles where there is a maintenance of posture
stabilization of body positions
contracts to maintain the upright position of the head
sternocleidomastoid
function of muscles where there is exemplified regulation of contents of urinary bladder, gall blader, heart, etc.
organ volume regulation
function of muscles where contraction generates 85% of body heat
thermogenesis
how much body heat is generated by muscles
85 percent
structure of striated muscle that is covered by epimysium and consist of many fascicles/fasciculi
muscle
joined together by perimysium and consist of many myofibers
perimysium
joined together by endomysium; actually a muscle cell covered by sarcolemma; consist of many myofibrils
myofibers
made up of myofilaments (thin and thick filaments)
myofibrils
thin filaments are made up of 3 proteins
actin
troponin
tropomyosin
possess the myosin binding sites which are covered by troponin-tropomyosin complex during muscle relaxation
actin proteins
covers the myosin binding sites of thin filaments
troponin-tropomyosin
made up of myosin proteins organized into heads (crossbridges) and tails
thick filaments (myosin)
bind to the myosin binding sites on actin molecules during muscle contraction
myosin heads
organized to become the functional unit of a muscle
thin and thick filaments
functional unit of a muscle
sarcomere
formed from the organization of thin and thick filaments into units
sarcomere
overlapping banded structures of sarcomere create these among skeletal and cardiac muscles
striations
parts of a sarcomere
z lines
a bands
m line
i bands
elastic filaments
bind sarcomeres together on one side; boundaries of a sarcomere
z lines
also called dark bands; made up of thick filaments and portions of thin filaments
a bands
bisects the A bands and connect them to one another
m lines
also called light bands; made up of thin filaments only
i bands
composed of protein titin/connectin which anchors the thick filaments to the Z discs to stabilize their positions
elastic filament
Two tubular system associated with the sarcomere
transverse tubule
sarcoplasmic reticulum
actually an invagination of the sarcolemma covering the myofiber
transverse (T) tubule
penetrates into the cell and runs between the SR; where nerve impulses travel towards the interior of the cell
transverse (T) tubule
releases Ca2+ during contraction, and sequesters the same during relaxation
sarcoplasmic reticulum (SR)
generation and travel of action potentials/nerve impulses to here
axon terminal
nerve impulses cause entrance of these into the axon terminal and release of neurotransmitters
calcium ions
neurotransmitters that are released from the synaptic vesicles through exocytosis
acetylcholine (ACh)
binding of ACh here located in the motor end plate of the sarcolemma
receptors
there is a generation and travel of action potentials here when ACh bind to receptors
transverse tubule
what happens when there is an opening of the channels in the terminal cisternae of the SR
release of calcium ions/calcium flood
where Ca2+ binds to expose the myosin binding sites
troponin-tropomyosin complex
this undergo a conformational change in their shape and slide away from the chain of the actin proteins, thus exposing the myosin binding sites
regulatory proteins
charged with energy from ATP, bind to the myosin binding sites on actin proteins
myosin heads
perform powerstroke and pull on actin threads towards the center of the sarcomere
myosin molecules
move toward the M line when myosin molecules pull on actin threads
i bands
these shorten to generate force when the myosin molecules pull on actin threads
sarcomeres
slide inward when the myosin molecules pull on these
actin threads
come toward each other when the myosin molecules pull on actin threads
z discs
characteristic of thin and thick filaments that do not change
length
what slide when myosin molecules pull on actin threads
filaments
synaptic cleft that breaks down ACh and returns it to the axon terminal
acetylcholinesterase (AChE)
binds to myosin heads and the myosin heads detach from the myosin binding sites on actin molecules
ATP
detaches from the troponin-tropomyosin complex and this protein regulatory complex slides back covering the myosin building sites on actin molecules
calcium
where Ca2+ is sequestered back by Ca2+ active transport pumps
sarcoplasmic reticulum
number of muscles in vertebrates
620 muscles
fibers are diagonal to the midline
oblique
fibers are parallel to the midline
rectus
fibers are perpendicular to the middle
transverse
– shortest
– longest
– largest
– smalles
– larger
– smaller
brevis – shortest
longus – longest
maximus – largest
minimus – smalles
major – larger
minor – smaller
– two head
– three heads
– four heads
biceps – two head
triceps – three heads
quadriceps – four heads
diamond-shaped
rhomboideus
saw-toothed
serratus
triangular
deltoid
trapezoid
trapezius
originates on the sternum and clavicle, inserts on mastoid process of the temporal bone
sternocleidomasteoid
originates on thyroid cartilage of larynx, inserts on greater horn of hyoid bone
thyrohyoid
bends a part
flexor
straightens a part
extensor
move a part away from the midline
abductor
move a part towards the midline
adductor
raises a part
levator
lowers a part
depressor
turns palm upward
supinator
turns palm downward
pronator
decreases the size of an opening
sphincter
makes a part more rigid
tensor
rotates a part
rotator
