exam (8-10) essay questions

Mary has been suffering from a bad knee for several months. She is a tennis player who often slides in to attack a ball; she is an aerobic devotee and a jogger. She visited an orthopedic surgeon last week who told her that he would ;like to have a look at her knee joint.He also told her that her symptoms indicated damage to the meniscus, and it might have to be removed. What will the doctor do to see the joint, and if the meniscus is removed will Mary be able to play tennis again?

the doctor will perform an arthroscopy on Mary in order to view the interior of the knee joint. If the meniscus is removed, there will be little impairment to the knee, but some loss of stability.

Probenecid inhibits the active resorption of uric acid in the kidney which leads to urinary excretion of uric acid. Explain why this drug would be useful in treating gout. Since uric acid is a normal waste product of nucleic acid metabolism, why are so many men suffering from a condition known as gouty arthritis? How does this product that should be eliminated in the urine cause so much pain when things go wrong?

uric acid is normally excreted by the urine, but when excess levels rise in the blood, uric acid is deposited as urate crystals in the soft tissue of joints. inflammation leads to gout. this drug would be useful in treating gout by excreting this excess uric acid through the urine instead of it depositing as crystals. males are more likely to suffer from gouty arthritis because they have higher blood levels of uric acid, and estrogen ( a sex hormone found in higher levels in females) increase the rate of uric acid excretion. Sometimes gout sufferers have an excessive rate of uric acid production; or it is possible that some are unable to flush uric acid in the urine fast enough. Untreated gout can be very destructive; the articulating bone ends fuse & immobilize the joint. Gout may run in families.

Maggie is a 28-year-old Caucasian woman who has newly diagnosed rheumatoid arthritis. She complains of painful, stiff hands and feet, feeling tired all the time, and reports an intermittent low-grade fever. She asks the nurse if she is going to be crippled. How might the nurse explain the pathophysiology of rheumatoid arthritis?

Rheumatoid arthritis (RA) is a chronic, systematic, and inflammatory disorder. RA is an autoimmune disease in which the body’s immune system attacks its own tissue. RA begins with inflammation of the synovial membrane of the affected joints. Fluid accumulates causing joint swelling & gradually, the inflamed synovial membrane thickens into a pannus, an abnormal tissue that clings to the articular cartilages. The nurse should explain that RA has a chronic crippling ankylosis stage where the bone ends fuse together, immobilizing the joint. However, not all cases involve restriction of joint movement and extreme pain.

Farhad begins typing his term paper on his new computer early one morning. After 8 hours of typing, he notices that his wrists are stiff and very sore. The next morning, Farhad begins to finish his paper, but soon finds his wrists hurt worse than last night. What is wrong?

Farhad is suffering from tendonitis. Tendonitis is inflammation of the tendon sheaths, and it is usually caused by overuse. If he continues to use the keyboard incorrectly, the tendonitis could develop into a very serious condition called carpal tunnel syndrome.

Synovial joints have five major features. What are they? Describe a typical synovial joint.

Articular cartilage, a joint cavity, an articular capsule, synovial fluid, and reinforcing ligaments. The general structure of a synovial joint contains: Articular cartilage is a thin, glassy-smooth hyaline cartilage that covers the ends of the articulating bones. Its spongy cushions absorb compression placed on the joint and prevent the bone ends from being crushed. The joint (synovial) cavity is a space that is filled with synovial fluid. The two-layered articular capsule encloses the joint cavity. The external layer is composed of dense irregular connective tissue that is continuous with the periosteum of the articulating bones. It strengthens the joint so that the bones are not pulled apart. The inner layer is a synovial membrane composed of loose connective tissue. It lines the fibrous capsule internally & covers all internal joint surfaces that are not hyaline cartilage. Synovial fluid is a viscous, slippery fluid that fills all free space within the joint cavity. This fluid is derived largely by filtration from blood flowing through the capillaries in the synovial membrane. It has a viscous, egg-white consistency due to hyaluronic acid (proteoglycan) secreted by cells in the synovial membrane, but it thins, becoming less viscous, as it warms during joint activity. Reinforcing ligaments cross synovial joints to strengthen the joint.

While the fingers can exhibit flexion and extension and other angular motions, the thumb has much greater freedom. Why?

The thumb possesses a saddle joint where each articular surface has both a concave and a convex surface.

Often people who exercise prudently seem to have fewer bouts with osteoarthritis. Will exercise prevent arthritis? If so, how?

Exercise does not prevent arthritis, but it strengthens muscles that in turn support and stabilize joints.

Greg is somewhat of a weekend athlete who has overextended himself by pitching baseball for a local team during the week and playing golf on the weekends for several hours. He presented himself to the emergency room last week with severe shoulder pain (at the glenohumeral joint). The physician told him that the X ray was not conclusive, but he may have damage to his rotator cuff. What is the rotator cuff, and how might he have caused this damage? What remedies will the physician recommend?

Greg has either stretched or torn his rotator cuff. He will be told to rest for a few months, and if the pain does not subside, surgery will be necessary. The rotator cuff is made up of four tendons that belong to the subscapularis, supraspinatus, infraspinatus, teres minor muscles and encircle the shoulder joint. They are vulnerable to damage when the arm is circumducted vigorously. Greg is obviously overdoing his activities by pitching four baseball games per week & playing golf on weekends.

Many inflammations of joint areas can be treated by injections of cortisone into the area. Why don’t we continually get injections rather than surgeries?

A joint inflammation is always a symptom of an underlying problem such as cartilage or ligament damage, arthritis, etc. Continued injection might cause the patient to reinjure the area, or it might mask a more severe injury that may appear later.

After reading a medical report, you learn that a 45-year-old female has the following

symptoms: inflammation of synovial membranes, accumulation of synovial fluid, pain

and tenderness about the joints, pannus formation, and some immobility at certain

joints. On the basis of these symptoms, what would the patient probably have?

rheumatoid arthritis

List the "five golden rules" of gross skeletal muscle activity.

With few exceptions, all muscles cross at least one joint. Typically, the bulk of the muscle lies proximal to the joint crossed All muscles have at least two attachments: the origin and the insertion. Muscles can only pull: they never push. During contraction, the muscle insertion moves toward the origin.

What is a fascicle? What is the result of different fascicle arrangements? List the seven different fascicle arrangements of human skeletal muscles and give a specific example of each.

Muscle cells are called muscle fibers. A bundle of muscle fibers is called a fascicle. A fascicle is surrounded by a connective tissue sheath called the perimysium. Fascicle arrangements produce skeletal muscles with different structures and functional properties, and determine their individual range of motion and power. Circular-orbicularis oris, orbicularis oculi Convergent-pectoralis major Parallel-sartorius Fusiform-biceps brachii Unipennate-extensor digitorum longus Bipennate-rectus femoris Multipennate-deltoid

Brian decided to enter a 5-mile race designed to raise money for a class trip. He did not do any preconditioning, nor has he ever jogged before. The morning after the race, Brian had so much pain in both his legs, he was unable to go to school. What caused this pain?

Brian was not conditioned for this type of run, and he now has shin splints. This is a condition in which the anterior tibialis muscle is irritated, and as the inflamed muscle swells, its circulation is impaired by the tight fascial wrappings, causing pain and tenderness.

Bodybuilders are known for their "great quads." Describe the quadriceps muscles.

These are the muscles of the front and sides of the thigh, and include the rectus femoris and the lateral, medial, and intermediate vastus muscles.

A woman mentions to her friend that another person on the beach has "great abs." What is she talking about?

The woman is referring to well-developed rectus abdominis muscles on some individual. This is a term coined by bodybuilders and refers to the bulging muscles between the tendinous intersections.

Muscles that act as synergists seem to have valuable functions, especially in stabilizing joints. Briefly explain their function.

Synergists aid prime movers by promoting the same movement or by reducing undesirable or unnecessary movements that might occur as the prime mover contracts.

How does an antagonist differ from a prime mover? How is it the same?

A prime mover is the muscle that causes the desired movement to occur. An antagonist is a muscle that opposes the action of the prime mover in a given movement. If, however, the direction of movement reverses, the former antagonist is now the prime mover and the former prime mover is now the antagonist.

An elderly woman, with extensive osteoarthritis of her left hip joint, entered the hospital to have a total hip joint replacement (prosthesis implantation). After surgery, her left hip had to be maintained in adduction to prevent dislocation of the prosthesis while healing was occurring. Physical therapy was prescribed to prevent atrophy of the gluteal muscles during the interval of disuse. Name the gluteal muscles and describe the action of each that was being prevented while the hip was adducted.

Gluteus maximus, gluteus medius, and gluteus minimus. These muscles originate on the pelvis; they act as major extensors of the thigh and abduct and rotate the thigh as well.

A wide receiver for the Dallas Cowboys pulled a hamstring muscle. What muscles could be affected and what would the effect be?

The muscles include the biceps femoris, semitendinosus, and semimembranosus. They are important flexors of the leg and extensors of the thigh. Injuries here could make it impossible to run properly or to bend the thigh.

Malcolm was bending over to pick up a heavy box when he was suddenly startled by a rat. He experienced severe pain in his back with muscle spasms and was unable to straighten up. What muscles could have been affected?

He probably affected the erector spinae muscles, since these readily go into spasms when the back is injured.

Which muscle is used for normal breathing and which additional muscles are used when performing strenuous exercises?

The diaphragm is the primary breathing muscle. The external intercostals are used to increase inspiration and are synergistic to the diaphragm. Forced exhalations use the internal intercostals

In emphysema, the lungs become overdistended with trapped air. Effective abdominal breathing is decreased. Describe the muscles involved when breathing becomes an active process, such as a patient who has emphysema.

The internal intercostal muscles form the deeper layer of the thorax and aid active (forced) expiration by depressing the rib cage.

Compare skeletal, smooth, and cardiac muscles as to their body location, microscopic anatomy, regulation of contraction, speed of contraction, and rhythmicity.

Body location-skeletal muscle is attached to bones or to skin (some facial muscles); cardiac muscle is located in the walls of the heart; smooth muscle is found in the walls of hollow visceral organs (other than the heart). Microscopic anatomy-skeletal muscle consists of very long, cylindrical, multinucleated cells with very obvious striations; cardiac muscle consists of branching chains of cells that are uninucleated and possess striations, and intercalated discs; smooth muscle consists of single fusiform, uninucleated cells that lack striations. Regulation of contraction-skeletal muscle is voluntary via nervous system controls, cardiac muscle is involuntary via the heart pacemaker, nervous system controls, and hormones; smooth muscle is involuntary via nervous system controls, hormones, other chemicals, and stretching. Speed of contraction-skeletal muscle is slow to fast; cardiac muscle is slow; smooth muscle is the slowest. Rhythmicity-skeletal muscle is arrhythmic; cardiac muscle is rhythmic; smooth muscle is sometimes rhythmic.

Describe the events that occur from the time that a motor neuron releases acetylcholine at the myoneural junction until muscle cell contraction occurs.

Acetylcholine is released, which diffuses through the synaptic cleft and attaches to receptors on the sarcolemma. The sarcolemma permeability to sodium ions increases briefly, causing sodium ions to rush into the muscle cell, which changes the electrical conditions of the resting sarcolemma. An action potential is initiated and sweeps over the entire sarcolemma. Calcium ions are released from storage areas inside the sarcoplasmic reticulum of the muscle cell. They attach to the myofilaments, which triggers the sliding of the myofilaments and causes a muscle cell contraction.

What is the effect of aging on skeletal muscles?

With aging, the amount of connective tissue in muscle increases and the amount of skeletal muscle tissue decreases, thus the muscles become stringier (more sinewy). Since skeletal muscle represents a larger portion of body weight, it begins to decline in elderly persons as this normal loss of muscle mass occurs. Another result of the loss in muscle mass is a decrease in muscle strength-strength decreases by about 50% by the age of 80. Regular exercise can help offset the effects of aging on the muscular system, and frail elders who begin to "pump iron" can rebuild muscle mass and significantly increase their functional strength.

A long-distance runner is about to enter a 5-mile race. Beforehand, he spends several minutes warming up. During the warm-up period, the phenomenon of treppe is occurring in body muscles being used. What is treppe and why does it occur?

When a muscle begins to contract after a long period of rest, its initial contacts are not very strong. Treppe is the staircase phenomenon in which muscles increase their strength of contraction due to increased availability of calcium. Additionally, the increased warmth due to activity causes an increase in the efficiency of muscle enzyme systems.

Explain the steps in the sliding filament theory of muscle contraction, following the spreading of an action potential along the sarcolemma.

An action potential triggers the sarcoplasmic reticulum to release calcium ions into the sarcoplasm of the muscle cell. The calcium ions bind to regulatory proteins on the actin filaments, changing both their shape and their position on the actin filaments. This action allows myosin receptor sites on the thin actin filaments to become exposed. The myosin heads attach to the myosin binding sites on the actin filaments. Energized by ATP, the myosin heads swivel toward the center of the sarcomere, attaching and detaching several times. In the process the thin actin filaments are pulled toward the center of the sarcomere. As this event occurs simultaneously in sarcomeres throughout the cell, the muscle cell shortens. When the action potential ends, the calcium ions are reabsorbed back into the sarcoplasmic reticulum storage areas, causing the regulatory proteins to resume their original shape and position. Since the myosin heads now have nothing to attach to, the muscle cell relaxes and returns to its original length.

Briefly, what causes rigor mortis?

Muscles begin to stiffen 3 – 4 hours after death. Maximum rigidity occurs at 12 hours. It gradually decreases over the next 48 – 60 hours as muscle proteins break down after death. In a living cell, there are more Ca+ ions outside the cell (in the extracellular matrix) than inside the cell. The gated proteins on the cell membrane prevent these ions from entering inside the cell. However a dying cell cannot control the Ca ions and they enter into the muscle cells and promote cross bridge formation. Following the death of an individual, ATP is rapidly consumed and cannot be replaced. Because cross bridge detachment and calcium active transport is ATP driven, calcium leakage from the sarcoplasmic reticulum causes attachment of cross bridges, and lack of ATP prevents detachments.

What ultimately stops muscle stimulation when the motor neuron ceases firing?

The ultimate switch is the enzyme acetylcholinesterase. When the neuron stops releasing ACh, the muscle would not stop contracting if the acetylcholinesterase did not split the ACh into its two components; acetyl and choline, making them release their binding sites.

What are the two special inclusions of skeletal muscle cells and how would they be useful to the cell?

Skeletal muscle cells require a lot of rapidly available fuel to burn in order to function properly. They also require a lot of oxygen to burn this fuel efficiently. Glycosomes store glycogen which can be quickly converted to glucose, which in turn can be burned to produce ATP. Myoglobin is a chemical much like hemoglobin in blood cells which can store large quantities of oxygen.

After removal of an elbow cast, Lauren noticed her arm was immovable. What happened to her arm?

Two things have occurred to Lauren while she was convalescing from her injury. First, the immobilization of the arm caused some muscle mass to atrophy. Second, the loss of muscle was replaced with tough connective tissue that locked her arm in place. With therapy the tissue can be stretched or torn enough to return the full range of motion.

A patient has no peristalsis in the gastrointestinal tract. Explain a possible complication of this condition.

Peristalsis is wavelike movement produced by the circular and longitudinal muscle fibers of the intestinal walls that propels the intestinal contents forward. Without peristalsis, the patient would be unable to expel their stool, leading to intestinal obstruction.

When a geriatric client is admitted to the rehabilitation unit, an important nursing measure is to prevent the loss of muscle mass. What is the term used for loss of muscle mass and how can the patient prevent it?

Disuse atrophy is degeneration and loss of muscle mass. The size, shape, tone, and strength of muscles (including the heart) are maintained with mild exercise and increased with strenuous exercise. Promoting exercise to maintain a patient's muscle tone, joint mobility, and cardiovascular function is an important nursing function.

The nurse encourages the patient to do his own activities of daily living such as bathing, feeding, dressing, and toileting activities. How do these activities promote physical conditioning?

These activities are isotonic exercises which produce muscle contraction and movement. Because the muscles contract, the shape, size, and strength of the muscles are maintained along with joint mobility.

Briefly explain where the energy comes from in a one-minute sustained muscle contraction.

The first 4-6 seconds of energy come from stored ATP in the muscle cell. 6-15 seconds of energy come from the transfer of creatine phosphate. 15-60 seconds of energy come from glycolysis which by now has begun full production of ATP from glucose.

What are caveoli?

Folds on the surface of smooth muscle cells that correspond to T tubules in skeletal muscle cells. These folds hold extracellular fluid which contains large amounts of calcium. When calcium channels open, Ca ions can thus quickly move into the cell.