week 6 (joints, movement & skeletal muscle, smooth and cardiac muscles) Flashcards
skeletal muscle
Muscles are attached to bones by tendons at their origins and insertions. Skeletal
muscles produce movements by pulling on bones.
Those skeletal muscles that produce movements do so by exerting force on tendons, which in turn pull on bones
or other structures (such as skin)
Because
each skeletal muscle fiber arises during embryonic development from
the fusion of a hundred or more small mesodermal cells called myoblasts
each mature skeletal muscle fiber has a
hundred or more nuclei. Once fusion has occurred, the muscle fiber loses
its ability to undergo cell division. Thus, the number of skeletal muscle
fibers is set before you are born, and most of these cells last a lifetime
Skeletal muscle also contains
connective tissues surrounding muscle fibers, and blood vessels and
nerves
origin
the attachment of a muscle’s tendon to the stationary bone is called the
origin is usually proximal
inseration
the attachment of the muscle’s other tendon to the movable bone
insertion distal
the insertion is usually pulled toward the origin
tendons
attach to muscle and secure the muscle to the bone
synvoial joint
The bones forming the joint have
a synovial cavity and are united by the dense irregular connective
tissue of an articular capsule, and of en by accessory ligaments
synvoial cavity
joint cavity between
the articulating bones. Because the synovial cavity allows considerable movement at a joint, all synovial joints are classified functionally
as freely movable
articular cartilage
The bones at a synovial joint are
covered by a layer of hyaline cartilage called
articular capsule
or joint capsule surrounds a synovial joint, encloses the synovial cavity, and
unites the articulating bones. The articular capsule is composed of two layers, an outer fibrous membrane and an inner synovial
membrane
synvoial membrane
is composed of areolar connective tissue with elastic fibers. At many synovial joints the synovial membrane includes accumulations of adipose tissue, called articular fat pads
fibrous membrane
of dense irregular connective tissue (mostly collagen fibers) that attaches to the periosteum of the articulating bones. In fact, the fibrous membrane is literally a thickened continuation of the periosteum between the bones.
The flexibility of the fibrous
membrane permits considerable movement at a joint, while its great tensile strength (resistance to stretching) helps prevent the bones from dislocating, the displacement of a bone from a joint.
The fibers of some fibrous membranes are arranged as parallel bundles of dense regular connective tissue that are highly adapted for resisting strains
ligament
is one of the principal mechanical
factors that hold bones close together in a synovial joint
synvoial fluid
Synovial
fluid consists of hyaluronic acid secreted by synovial cells in the
synovial membrane and interstitial fluid filtered from blood plasma.
It forms a thin film over the surfaces within the articular capsule. Its
functions include reducing friction by lubricating the joint, absorbing
shocks, and supplying oxygen and nutrients to and removing carbon
Synovial fluid also
contains phagocytic cells that remove microbes and the debris that
results from normal wear and tear in the joint
dioxide and metabolic wastes from the chondrocytes within articular
cartilage
menisci
crescent-shaped
pads of fibrocartilage lie between the articular surfaces of the bones
and are attached to the fibrous capsule
1) shock absorption; (2) a better fit between articulating bony surfaces; (3) providing adaptable surfaces for combined
movements; (4) weight distribution over a greater contact surface;
and (5) distribution of synovial lubricant across the articular surfaces
of the joint.
hinge joint
in which the articular surfaces are molded to each other in such a manner as to permit motion only in one plane
it is like a line shape and then another bone forming to it
examples: elbow, knee, interphalangeal (IP) joints of the hand and foot and the tibiotalar joint of the ankle
ball and socket joint
Ball-and-socket joint, also called spheroidal joint, in vertebrate anatomy, a joint in which the rounded surface of a bone moves within a depression on another bone, allowing greater freedom of movement than any other kind of joint
example: shoulder nad hip joints
pivot joint
Pivot joints, also known as rotary joints, are a type of synovial joint that permit axial rotation. The moving bone rotates within a ring formed by the concave surface of a second bone and an adjoining ligament
example would be the 2nd vetrebrea and neck bone and joint of wrist
abduction
the movement of a bone away from the midline
adduction
is the movement of a bone towards midline
circumduction
is movement
of the distal end of a body part in a circle
internal/medial rotation
anterior surface of a bone of the limb is turned toward the midline, the movement is called medial (internal) rotation
external/lateral rotation
anterior surface of the
bone of a limb is turned away from the midline, the movement is
called lateral (external) rotation
extension
Increase in angle between articulating bones,
flexion
Decrease in angle between articulating bones,
usually in sagittal plane
joint
is a point of contact between two bones, between
bone and cartilage, or between bone and teeth
fibrous joint
There is no synovial cavity, and the bones
are held together by dense irregular connective tissue that is rich in
collagen fibers.
cartilaginous joint
There is no synovial cavity,
and the bones are held together by cartilage
synarthrosis
An immovable
joint
amophiarthrosis
A
slightly movable joint
diarthrosis
A freely movable
joint. The plural is diarthroses. All diarthroses are synovial joints.
They have a variety of shapes and permit several different types of movements.
sutures (fibrous joint)
is a fibrous joint
composed of a thin layer of dense irregular connective tissue; sutures
occur only between bones of the skull
They are
immovable or slightly movable
head bons
syndesmoses (fibrous joint)
is a fibrous joint in which there is a greater
distance between the articulating surfaces and more dense irregular
connective tissue than in a suture
between tibia and fibula
interosseous membranes (fibrous joint)
which is a substantial sheet of dense irregular connective tissue that binds neighboring long bones and permits slight
movement
provide an increased attachment surface for muscles that produce movements of the digits of the
hand and foot.
synchondroses (cartilaginous joint)
is a cartilaginous joint in which the connecting
material is hyaline cartilage and is slightly movable
the joint between the first rib and the manubrium of the sternum
symphyses (cartilaginous joint)
is a
cartilaginous joint in which the ends of the articulating bones are
covered with hyaline cartilage, but a broad, flat disc of fibrocartilage
connects the bones
and at the intervertebral joints between the bodies
of vertebrae
three types of muscle fibres
smooth, caridiac and skeletal
excitability of muscules
the ability to respond to a stimulus, which may be delivered from a motor neuron or a hormone
a property of both muscle and nerve cells that was is the ability
to respond to certain stimuli by producing electrical signals called
action potentials (impulses). Action potentials in muscles are referred to as muscle action potentials; those in nerve cells are called
nerve action potentials.
contractility of muscules
Contractility is the ability of muscle cells to forcefully shorten. Contractility allows muscle tissue to pull on its attachment points and shorten with force
the ability of muscular tissue to
contract forcefully when stimulated by an action potential. When a
skeletal muscle contracts, it generates tension (force of contraction)
while pulling on its attachment points.
elasticity of muscles
the ability to stretch a muscle to reach its full range of movement without restriction
extensibility of muscules
Extensibility is the ability of a muscle to be stretched
is the ability of muscular tissue to
stretch, within limits, without being damaged. The connective tissue
within the muscle limits the range of extensibility and keeps it within
the contractile range of the muscle cells. Normally, smooth muscle
is subject to the greatest amount of stretching. For example, each
time your stomach fills with food, the smooth muscle in the wall is
stretched. Cardiac muscle also is stretched each time the heart fills
with blood.
motor unit
made up of a motor neuron and all of the skeletal muscle fibers, also known as sarcomere innervated by the neuron’s axon terminals. Groups of motor units often work together as a motor pool to coordinate the contractions of a single muscl
somatic motor nervous system
somatic nervous system, or voluntary nervous system is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles
somatic motor nervous system can not happen withoutthe use of skeletal muscles
significance of nerve impulses being delivered to skeletal muscle tissue
when a neurotransmitter binds to a receptor, it triggers a new nerve impulse on the muscle fibre membrane. Because of the special way that muscle fibres are structured, this nerve impulse propagates rapidly throughout the fibre and makes it contract
without nerve impulses, we would not be ale to move our skeletal muscle tissue
cerebral motor cortex in relation to skeletal muscles
cerebral motor cortex is what sends these impulses to the areas they need to be. without it we would not be able to move.
cerebellum
The cerebellum has special sensors that detect shifts in balance and movement. It sends signals for the body to adjust and move
maintains balance of the body
basal nuclei
The basal ganglia are responsible for voluntary motor control, procedural learning, and eye movement, as well as cognitive and emotional functions
what is the importance of calcium ions (Ca2+)
calcium ions cause the release of acetylcholine at the neuromuscular junction. as well, calcium release from the sarcoplasmic reticulum allows ‘bridge’ formation to occur between actin and myosin
tendon
the connective tissues that transmit the mechanical force of muscle contraction to the bones; the tendon is firmly connected to muscle fibres at one end and to components of the bone at its other end. … A tendon is composed of dense fibrous connective tissue made up primarily of collagenous fibres.
epimysium
is the outer layer, encircling
the entire muscle. It consists of dense irregular connective tissue
deep fascia
Deep fascia (or investing fascia) is a fascia, a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments.
blood vessel
The blood vessels are the components of the circulatory system that transport blood throughout the human body
perimysium
is also a layer of
dense irregular connective tissue, but it surrounds groups of 10
to 100 or more muscle fibers, separating them into bundles called
fascicles
fascicle
Many fascicles are large
enough to be seen with the naked eye. They give a cut of meat its
characteristic “grain”; if you tear a piece of meat, it rips apart along
the fascicles
endomysium
penetrates the interior of each fascicle and separates individual muscle fibers from one
another. The endomysium is mostly reticular fibers.
muscle fiber (cell)
Long cylindrical cell covered by endomysium and sarcolemma; contains
sarcoplasm, myofibrils, many peripherally located nuclei, mitochondria,
transverse tubules, sarcoplasmic reticulum, and terminal cisterns. The
fiber has a striated appearance.
blood capillary
the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins). The primary function of capillaries is the exchange of materials between the blood and tissue cells
motor neuron
cells in the brain and spinal cord that allow us to move, speak, swallow and breathe by sending commands from the brain to the muscles that carry out these functions
sarcolemma
he sarcolemma functions as a barrier between the extracellular and intercellular parts of the muscle fiber cells
The sarcolemma is the plasma membrane of the muscle cell and is surrounded by basement membrane and endomysial connective tissue
The cell membrane of a myocyte
myofirl
Threadlike contractile elements within sarcoplasm of muscle fiber that
extend entire length of fiber; composed of filaments
filaments (myofilaments)
Contractile proteins within myofibrils that are of two types: thick
filaments composed of myosin and thin filaments composed of actin,
tropomyosin, and troponin; sliding of thin filaments past thick filaments
produces muscle shortening
sacroplasm
Within the sarcolemma is the sarcoplasm (SAR-koˉ-plazm), the cytoplasm of a muscle fiber. Sarcoplasm includes a substantial amount of
glycogen, which is a large molecule composed of many glucose molecules
z plates
Narrow, plate-shaped regions of dense material that separate
one sarcomere from the next.
Contractile proteins
Proteins that generate force during muscle contractions.
Myosin
Contractile protein that makes up thick filament; molecule consists of a tail and two myosin heads, which bind to myosinbinding sites on actin molecules of thin filament during muscle contraction.
Actin
Contractile protein that is the main component of thin filament; each actin molecule has a myosin-binding site where
myosin head of thick filament binds during muscle contraction.
Tropomyosin
Regulatory protein that is a component of thin filament; when skeletal muscle fiber is relaxed, tropomyosin covers
myosin-binding sites on actin molecules, thereby preventing myosin from binding to actin.
Troponin
Regulatory protein that is a component of thin filament; when calcium ions (Ca2+) bind to troponin, it changes shape; this
conformational change moves tropomyosin away from myosin-binding sites on actin molecules, and muscle contraction
subsequently begins as myosin binds to actin.
Regulatory proteins
Proteins that help switch muscle contraction process on and off.
cardaric muscle tissue
Only the heart contains cardiac muscle tissue, which forms most of the heart wall. Cardiac muscle is also striated, but its action is involuntary. The alternating contraction and relaxation of the heart is not consciously controlled. Rather, the heart beats because it has a natural pacemaker that initiates each contraction. This built-in rhythm is termed autorhythmicity Several hormones and neurotransmitters can adjust heart rate by speeding or slowing the pacemaker.
smooth muscle tissue
Smooth muscle tissue is located in the walls of hollow internal structures, such as blood vessels, airways, and most organs in the abdominopelvic cavity. It is also found in the skin, attached to hair follicles. Under a microscope, this tissue lacks the striations of skeletal and cardiac muscle tissue. For this reason, it looks nonstriated, which is why it is referred to as smooth. The action of smooth muscle is usually involuntary, and some smooth muscle tissue, such as the muscles that propel food through your gastrointestinal tract, has autorhythmicity.
vertebral column function
is to provide proper positioning and posture for movement of the appendages and maintaining an upright position. the curves of the vertebral column are important in providing proper position. the muscles attached to the vertebrae allow for movement of the column and maintaining proper posture. these muscles are not for lifting
fulcrum
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muscle origin
Muscle origin refers to a muscle’s proximal attachment the end of the muscle closest to the torso
muscle insertion
insertion refers to a muscle’s distal attachment—the end of the muscle furthest away from the torso
antagonistic skeletal muscle pairs
the muscle that is relaxing or lengthening is called the antagonist
An antagonist muscle is in opposition to a prime mover in that it provides some resistance and/or reverses a given movement
prime mover
The prime mover, sometimes called the agonist, is the muscle that provides the primary force driving the action.
The muscle that is contracting is called the agonist
synergist
muscles that work together to create a movement as synergists. For example, iliacus, psoas major, and rectus femoris all can act to flex the hip joint.
fixator
serves as a stabilizer of one part of the body during movement of another part. It allows the agonist muscle to work effectively by stabilizing the origin of the agonist muscle so that the latter can pull against the bone without it moving thereby achieve an effective contraction.
flexation/extentsion in the elbow
the type of joint is a hinge joint
The origin of briceps brachaii at the scapula and the insertion into the radius. it contrations/shortens when you flex
brachanii biceps
Origin of Long Head: scapula
Origin of Lateral Head: Lateral and posterior surfaces of the humerus
Origin of Medial Head: Posterior surfaces of the humerus
inseration ulna
when it contratations the elbow extends
muscle tone
is the amount of tension (or resistance to movement) in muscles
isotonic contration
An isotonic muscle contraction occurs when the force or tension in the muscle remains constant while the length of the muscle changes
isometric contration
isometric contraction is a muscle contraction without motion. Isometric contractions are used to stabilize a joint, such as when a weight is held at waist level neither raising nor lowering it.l
tendon sheaths
elongayed bursa wrapped completely around tendon sunjected to friction
bursae
sacs lined with synovial membrane
contianed synovial fluid
reduce friction where ligaments, muscles, skin, tendons, or bones rub together
nonaxial
slipping movements only
Found between the proximal ends of the ulna and radius
uniaxial
Movement occurs in one plane. An example is the elbow joint.
biaxial
Movement can occur in two planes. An example is the wrist.
multiaxial
movement in or around all three planes
the shoulder/hip joints
angular movements
flexion, extension, hyperextention, abduction, adduction, circumduction
rotation
medial and lateral rotation
smooth muscle tissue
Description Smooth muscle tissue consists of nonstriated fibers (lack striations, hence the term smooth). Smooth muscle fiber is a small spindleshaped cell thickest in middle, tapering at each end, and containing a single, centrally located nucleus. Gap junctions connect
many individual fibers in some smooth muscle tissue (for example, in wall of intestines). Usually involuntary; can produce powerful
contractions as many muscle fibers contract in unison. Where gap junctions are absent, such as iris of eye, smooth muscle fibers
contract individually, like skeletal muscle fibers.
Location Iris of eyes; walls of hollow internal structures such as blood vessels, airways to lungs, stomach, intestines, gallbladder, urinary bladder,
and uterus.
Function Motion (constriction of blood vessels and airways, propulsion of foods through gastrointestinal tract, contraction of urinary bladder and gallbladder).
autorhythmicity
unique feature of cardiac muscle cells. These cells are able to generate the action potential at a certain rate without any external stimulus due to which the heart beats continuously and rhythmically
initiation of contration in smooth muscles
Acetylcholine and norepinephrine
released by autonomic motor
neurons; several hormones; local
chemical changes; stretching
Calmodulin and myosin light chain
kinase
dilation of smooth muscles
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bronchi in relation to smooth muscles
smooth muscle contraction induces airway narrowing. The smooth muscle also contributes to bronchial inflammation by secreting a range of inflammatory mediators, recruiting and activating inflammatory cells, such as mast cells or T-lymphocytes.
Postganglionic parasympathetic fibers will release acetylcholine causing the constriction of the smooth muscle layer surrounding the bronchi.
arterioles in relation to smooth muscles
The primary function of vascular smooth muscle cells within the media is to control vascular diameter via cell contraction and relaxation processes
peristalsis
series of muscle contractions. These contractions occur in your digestive tract. Peristalsis is also seen in the tubes that connect the kidneys to the bladder. Peristalsis is an automatic and important process
squeeze of the espoguous
factors of which movement function is altered
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motor neuron
cells in the brain and spinal cord that allow us to move, speak, swallow and breathe by sending commands from the brain to the muscles that carry out these functions
motor end plate/neauromuscular junctions
Neuromuscular junctions, also called motor end plates, are specialised chemical synapses formed at the sites where the terminal branches of the axon of a motor neuron contact a target muscle cell
synaptic vesicle
synaptic vesicle
acetylcholine
chief neurotransmitter of the parasympathetic nervous system, the part of the autonomic nervous system (a branch of the peripheral nervous system) that contracts smooth muscles, dilates blood vessels, increases bodily secretions, and slows heart rate
acetlycholine receptors
a membrane protein that binds to the neurotransmitter acetylcholine
acetylcholinesterase
cholinergic enzyme primarily found at postsynaptic neuromuscular junctions, especially in muscles and nerves. It immediately breaks down or hydrolyzes acetylcholine (ACh), a naturally occurring neurotransmitter, into acetic acid and choline
extend of movement in a synvoial joint
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