Medical doctors who specialize in the diagnosis and treatment of disorders of the joints, muscles, and bones are called rhumatologists.
They diagnose and treat diseases such as arthritis, osteoporosis, and ankylosing spondylitis.
Rheumatoid arthritis affects the joints of the hands, feet, and spine.
Affected joints become stiff and swollen.
Although it is known that the body's immune system mistakenly attacks healthy tissue, the cause of the disease remains a mystery.
Immune cells from the blood enter joints and cause inflammation.
The bones rub against each other causing pain.
The age of onset is usually 40-50 years of age and it is more common in women than men.
There are a number of symptoms that can be used to diagnose RA.
A contrast agent, such as a dye, that is opaque to Xrays, is used in arthroscopy.
The soft tissue structures of joints can be visualized.
The surface of soft tissues lining the joint is different from the regular X-ray which shows the bones.
Changes in joint cartilage can be detected before bones are affected.
rheumatologists have a number of treatment options to choose from.
If you want to treat early stages with rest of the affected joints, you can use a cane.
Exercise can be used to strengthen the muscles around the joint when inflammation is low.
If joint damage is more extensive, medications can be used to relieve pain.
Aspirin and other anti inflammatory drugs may be used.
In cases of severe joint damage, surgery may be required.
By the end of this section, you will be able to classify the different types of muscle tissue.
Muscles allow for motions such as walking, and they also facilitate bodily processes.
The body has three types of muscle tissue.
Light microscopy shows the three types of muscle tissue in the body.
Smooth muscle cells have a single plump nucleus at each end.
Cardiac muscle cells are short.
The nucleus of the cell is in the center of the cytoplasm.
Skeletal muscle is called voluntary muscle because it can be controlled by thought.
Skeletal muscles are long and cylindrical and can be seen under a microscope.
The striations are caused by the regular arrangement of contractile proteins.
Multiple nuclei are present in a single cell.
Smooth muscle has no striations, is not under control, has only one nucleus per cell, and is called involuntary muscle.
Cardiac muscle is striated, but unlike skeletal muscle, it can't be consciously controlled.
It has one nucleus per cell and is distinguished by the presence of intercalated disks.
Skeletal muscle fiber is a cell in the body.
These cells have diameters of up to 100 um and lengths of up to 30 cm.
The sarcolemma is the site of action potential conduction.
The structures are parallel to the muscle fiber.
Hundreds to thousands of myofibrils can be found inside one muscle fiber because they are only 1.2 um in diameter.
As myofibrils shorten, the entire muscle cell contracts.
A muscle cell is surrounded by a sarcolemma and a sarcoplasm.
There are many fibrils in a muscle fiber.
The striated appearance of skeletal muscle tissue is caused by repeating bands of the actin and myosin that are present along the length of myofibrils.
The alignment of myofibrils in the cell causes the entire cell to appear striated or banded.
The Z disc or Z line is a dense line that runs through the middle of each band.
One sarcomere is the space between two consecutive Z discs and contains one entire A band and two halves of an I band, one on either side of the A band.
A myofibril is composed of many sarcomeres running along its length, and as the sarcomeres individually contract, the myofibrils and muscle cells shorten.
A sarcomere is the region from one Z line to the next Z line.
The striation pattern characteristic of skeletal muscle is caused by many sarcomeres in myofibril.
There are two main types of filaments, thick and thin.
The dense appearance of the region at which thick and thin filaments overlap is due to the lack of space between them.
There is a central region of the A band that only contains thick filaments.
The H zone is the lightest part of the A band and is called the central region.
There is a vertical line called the M line in the middle of the H zone.
The Z disc and M line hold myofilaments in place to maintain the structure of the myofibril.
Myofibrils are connected to each other by desmin.
There are thick and thin filaments.
The myosin is in the thick filaments.
The heads of myosin molecule align on either side of the thick filament where the thin filaments overlap, whereas the tail of myosin molecule connects with other myosin molecule to form the central region.
Actin is the primary component.
tropomyosin and troponin are part of the thin filament.
Actin has places for myosin attachment.
Actin-myosin interactions can be prevented when the muscles are at rest.
Troponin is composed of three parts.
One component binding to tropomyosin, one component binding to actin, and one component binding Ca2+ ion.
The animation shows the organization of muscles.
The sarcomere must be shortened for a muscle cell to contract.
The components of sarcomeres are thick and thin.
They slide by one another, causing the sarcomere to shorten.
The sarcomere's named bands have different degrees of muscle contraction and relaxation.
The mechanism of contraction is the binding of myosin to actin.
The I band gets smaller when the Z lines move closer together.
At full contraction, the A band stays the same width.
Some regions shorten while others stay the same.
A sarcomere is the distance between two consecutive Z discs or Z lines; when a muscle contracts, the distance between the Z discs is reduced.
The H zone is the central part of the A zone.
The I band has thin filaments and shortens.
The A band is the same length, but different bands move closer together during contraction.
The thick filaments pull the thin ones toward the center of the sarcomere.
The zone of overlap increases as thin and thick filaments move inward.
As myosin heads bind to actin, muscle shortening occurs.
The action requires energy.
Myosin binding to actin at a binding site.
Myosin has a binding site for ATP that hydrolyzes it to ADP.
Actin and myosin are able to detach from each other because of the binding of myosin and actin.
The newly bound ATP is converted to Pi.
The binding site of myosin is the location of the myosinidase.
The angle of the myosin head is changed by the release of energy.
The myosin head has potential energy and is in a position for further movement.
If actin binding sites are unavailable, the myosin will remain attached to the high energy configuration.
Myosin can use the stored energy as a change.
The actin is pulled along by the myosin head.
The actin is pulled and the filaments move towards the M line.
The power stroke is the step at which force is produced.
The sarcomere shortens as the actin is pulled towards the M line.
The myosin head is in a high-energy configuration when it is cocked.
At the end of the power stroke, the myosin head is in a low-energy position.
The cross-bridge formed after the power stroke is still in place and actin and myosin are bound together.
The cross-bridge cycle can start again if myosin is attached, and further muscle contraction can occur.
The video explains how a muscle contraction is signaled.
Ca2+ binding to the actin active site causes the cross-bridge muscle contraction cycle.
Actin moves relative to myosin with each contraction cycle.
The power stroke happens when the ATP is hydrolyzed.
The power stroke occurs when the myosin head is missing.
Actin and myosin are separated when a muscle is resting.
Actin can't binding to the active site on myosin without blocking the binding sites.
The myosin-binding site on an actin molecule must be uncovered to enable a muscle contraction.
This can only happen in the presence of calcium, which is kept very low in the sarcoplasm.
There are changes in troponin that allow tropomyosin to move away from the myosin binding sites.
A cross-bridge can form between actin and myosin after the tropomyosin is removed.
Cross-bridge cycling continues until Ca2+ ion and ATP are no longer available and tropomyosin covers the binding sites on actin.
There is a link between the action potential in the sarcolemma and the start of a muscle contraction.
The neural signal for calcium release is the sarcoplasmic reticulum.
Each muscle is controlled by a motor neuron, which sends signals from the brain to the muscle.
The end of the neuron's axon is called the synaptic terminal.
The synaptic terminal is separated from the motor end plate by a small space.
The neuron's axon branches through the muscle and connects to individual muscle fibers at a neuromuscular junction.
The ability of cells to communicate requires that they use energy to create an electrical signal.
The charge gradient is carried by the ion.
The concentration and electrical influence of each ion.
If they are allowed to do so, the ion will distribute themselves evenly like milk will eventually mix with coffee.
They can't return to an evenly mixed state.
The K+ ion and Na+ ion are moved inside the cell by the sodium-potassium ATPase.
This has a small electrical charge but a big concentration.
There is a lot of K+ in the cell.
K+ channels are open 90 percent of the time, and it is possible to leave the cell through 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 888-349-8884 Na+ is outside the cell because channels are rarely open.
A negative charge is left behind when K+ leaves the cell.
At rest, there is a large concentration of Na+ in the cell, and negative charges left in the cell.
There is a resting potential.
A separation of electrical charge is capable of doing work.
It is the same as a battery.
The transmembrane potential is much smaller (0.07 V) so the small value is expressed as mV or 70 mV.
A minus sign indicates the excess of negative charges inside the cell, which is -70 mV.
The Na+ ion will enter the cell if an event changes the permeability.
That will change the current state of affairs.
An action potential is an electrical event that can be used as a cellular signal.
Nerves and muscles communicate through neurotransmitters.
The release of neurotransmitters from the synaptic terminal into the synaptic cleft allows them to diffuse across the synaptic cleft and bind to a receptor molecule on the motor end plate.
The junctional folds in the sarcolemma create a large surface area for the neurotransmitter to bind to.
When a neurotransmitter signal is sent to the cell, the sodium channels open and Na+ can be passed into it.
Acetylcholine is a neurotransmitter that is released by motor neurons.
When an action potential travels down the motor neuron's axon, it causes altered permeability of the synaptic terminal and an influx of calcium.
The release of neurotransmitter from the vesicles into the cleft is aided by the Ca2+ ion.
Once released by the synaptic terminal, ACh diffuses across the synaptic cleft to the motor end plate.
The ion channels open when a neurotransmitter is binding to the muscle cell.
This reduces the voltage difference between the inside and outside of the cell.
An end-plate potential is the depolarization that occurs when ACh is binding at the motor end plate.
The depolarization spreads along the sarcolemma, creating an action potential as sodium channels adjacent to the initial depolarization site sense the change in voltage and open.
A wave of depolarization is created when the action potential moves across the cell.
AChE resides in the synaptic cleft so that it doesn't stay bound to ACh, which would cause unwanted muscle contraction.
The diagram shows a contraction of a muscle.
The sarcoplasmic reticulum is found in muscle cells.
Acetylcholinesterase is adversely affected by the nerve gas sarin.
The membrane is back to its resting state after depolarization.
During repolarization, the voltage-gated sodium channels close.
The channels are at 90% conductance.
The resting state, which is negatively charged inside relative to the outside, is restored because of the transport of ion.
During the period of time known as the refractory period, the membrane can't generate another action potential.
The ion channels can return to their resting configurations during the refractory period.
The K+ leaks out and the negative charge is left behind when the Na+ is moved back out of the cell.
The membranes can be depolarized very quickly.
Neural control leads to the formation of actin-myosin cross-bridges.
Skeletal movement is caused by these contractions pulling on bones.
The amount of force created by tension can vary, and the pull exerted by a muscle is called tension.
This allows the same muscles to move heavy objects.
The amount of tension produced depends on the cross-sectional area of the muscle fiber.
The amount of tension that a muscle fiber can produce is determined by the number of cross-bridges formed between actin and myosin.
Cross-bridges are only formed where thick and thin filaments overlap.
More myosin will pull on actin if more crossbridges are formed.
The ideal length of a sarcomere depends on the thickness of the filaments.
If a sarcomere is stretched past an ideal resting length, thick and thin filaments do not overlap to the greatest degree, and fewer cross-bridges can be formed.
Less tension is produced because fewer myosin heads pull on actin.
The H zone is composed of myosin tails and the zone of overlap is reduced as the sarcomere is shortened.
Actin will not bind myosin in this zone because it is myosin heads that form cross-bridges.
If the sarcomere is shortened even more, thin filaments begin to overlap with each other, reducing cross-bridge formation even further.
If the sarcomere is stretched to the point at which thick and thin filaments do not overlap, no cross-bridges are formed and no tension is produced.
This amount of stretching is not usually done because of the opposition of accessory proteins, internal sensory nerves, and connective tissue.
The number of myofibers within the muscle that receive an action potential is the primary variable determining force production.
The motor cortex of the brain only responds to a small number of myofibers when the biceps is used to pick up a pencil.
If stimulated, myofibers respond fully.
Every myofiber participates in the signals from the motor cortex when you pick up a piano.
The force the muscle can produce is close to this.
Increasing the number of signals per second can increase the force because the tropomyosin is flooded with calcium.
There are three types of skeletons.
The ossification of the body is called inmembranous ossification.
The process of bone development is called a hydrostatic skeleton.
A hard external chondrocytes divide and produce hyaline cartilage.
Cartilage is replaced with bone by osteoblasts.
Appositional growth allows movement through muscles.
An internal skeleton is composed of bone tissue at the surface of bones.
The processes of bone deposition by osteoblasts and attachment to muscles are involved in bone remodeling.
The human skeleton is made of bones.
It can take several months for a bone to be repaired.
The bones of the skull, ossicles of the ear, hyoid bone, vertebral column, and 38.3 Joints and Skeletal Movement ribcage are part of the axial skeleton.
Joints are divided into bones by the structural classification.
The ossicles of the middle ear are made of six bones.
The bones of the neck and jaw are held together by the same tissue.
There are 26 bones in the vertebral column and three types of joints that protect the spine.
Cartilage is connected by costal bones to the sternum and ribs in cartilaginous joints.
The limbs are made up of cartilaginous joints.
There is a space between the clavicles and the scapulae.
The upper limb has bones.
There are 30 bones in the arm, forearm, and hand.
The lower limbs are attached to the skeleton by three categories.
The lower limb has bones of the thigh, the leg, and is classified as one of four different types.
The bone is moving past each other.
The angle between the Bone bones and the osseous tissue is what causes the movement.
The movement of specialized cells is called rotation movement.
The bone rotates around its axis.
Special human skeleton can be divided into long bones, short bones, and movements.
The bone tissue is composed of osteons and forms the external layer of all movement.
Spongy bone tissue is composed of trabeculae and joints are classified into six different categories on the forms the inner part of all bones.
Skeletal formation is one of the three types of muscle tissue in the body.
The muscle, cardiac muscle, and smooth muscle are transduced by excitation-contraction.
The electrical signal from the neuron to the muscle is composed of sarcomeres, which are the functional electrical signals on the muscle.
When force is used, muscle contraction occurs.
The thickness of the sarcomeres determines how much force the whole muscle produces.
The bone tissue is cylindrical.
The power stroke occurs when the length of the ADP andphosphate are aligned.
The power stroke occurs when there are no blood vessels in the canals.
As an organisms grows, only the endoskeletons can grow.
Less mechanical leverage is provided by skeletons.
The groups of vertebrae are responsible for the growth of long.
The cells responsible for bone resorption are not known.
A high ankle injury is caused by osteoclasts stretching the tibia and fibula.
The bone is compact.
The myosin-binding site on actin is blocked by osteons.
Osteoporosis is a condition in which bones become weak.
There is a cell in a muscle fiber.
The activity of the bone helps to remove the neurotransmitter.
The movement of bone away from the midline of the d is not called a body.
flaccid paralysis of the muscles is caused by botulinum toxin and can be used for cosmetic purposes.
Which of the following isn't a characteristic of the acetylcholinesterase.
If a person is initially standing still, they can protect their internal step forward.
The person should hold his foot at the same angle.
How would the muscles be affected by a sideways curve?
Skeletal muscles are only capable of producing a mechanical force when women cause babies to be born without an arm.