A&P ALL CHAPTERS REVIEW QUESTIONS (Clinical application & critical thinking)

Jay Beckenstein went to weight-lifting camp in the summer between seventh and eighth grade. He noticed that the camp trainer put tremendous pressure on him and his friends to improve their strength. After an especially vigourous workout, Jay's arm felt extremely sore and weak around the elbow. He went to the camp doctor, who took X rays and then told him that the injury was serious, for the "end of his upper arm bone was starting to twist off." What had happened? Could the same thing happen to Jay's 23-year-old sister, Trixie, who was also starting the program of weight lifting? Why or why not?

Presumably the epiphyseal plate-bone junction has separated. -This wouldn't happen to Jay's 23-year-old sister Trixie because at her age, epiphyseal plates have been replaced by bone and are no longer present.

Robert, a brilliant computer analyst, suffered a blow to his anterior skull from a falling rock while mountain climbing. Shortly thereafter, it was obvious to his coworkers that his behavior had undergone a dramatic change. Although previously a smart dresser, he was now unkempt. One morning, he was observed defecating into the wastebasket. His supervisor ordered Robert to report to the company's doctor immediately. What region of Robert's brain was affected by the cranial blow?

Frontal lobes, specifically the prefrontal cortex, which mediates personality and moral behavior.

What would a long bone look like at the end of adolescence if bone remodeling did not occur?

-Because the changes throughout adolescence involve changes in stress associated with muscle growth, and sex steroids. -Sex steroids affect bone deposition, a lack of bone remodeling during adolescence would keep bones in more of a preadolescent form. -Bones would retain a thinner, less dense appearance than would usually be expected

Cynthia, a 16-year-old girl, was rushed to the hospital after taking a bad spill off the parallel bars. After she had a complete neurological workup, her family was told that she would be permanently paralyzed from the waist down. The neurologist then outlined for Cynthia's parents the importance of preventing complications in such cases. Common complications include urinary infection, bed sores, and muscular spasms. Using your knowledge of neuroanatomy, explain the underlying reasons for these complications.

-Cynthia's waist-down paralysis is a result of damage to nonspecific and specific ascending pathways, which causes a loss of sensory input to the brain from the extremities, and damage to the upper, but not lower, motor neurons of the descending pathways. -All of this results in loss of voluntary control of muscle movements, but leaves reflexive movements intact. -Therefore, bedsores would be an issue, because Cynthia will be immobilized for long periods and cannot feel the localized compressions that lead to them. As a consequence of both sensory and voluntary motor loss, she is prone to bladder infections and incomplete and infrequent voiding because she lacks the ability to feel when her bladder is full, allowing it to become overfull. -Muscle spasms result from the reflexive contractions directed by the lower motor neurons that are still intact.

In adults, over 90% of all cancers are either adenomas, or carcinomas. Why of the four tissue types gives rise to most cancers? Why?

-Epithelium, because epithelia remain mitotic throughout life. This is not the case for nervous and muscle tissue, and some forms of connective tissue.

Your friend is trying to convince you that if the ligaments binding the bones together at your synovial joints contained more elastic fibers, you would be much more flexible. Although there is some truth to this statement, such a condition would present serious problems. Why?

-If ligaments contained more elastic fibers they would be more stretchy; thus joints would be more flexible. -However, the function of the ligaments is to bond bones together securely so proper controlled joint movement can occur. -More elastic ligaments would result in floppy joints in which the bones involved in the joint would be prone to misalignment and dislocation.

Why do you think wheelchair-bound people with paralyzed lower limbs have thin, weak, leg and thigh bones?

-People who are bound to wheelchairs have thin and weak legs and high bones because the bones are no longer subjected to weight-bearing stress and therefore lose calcium. -Atrophy occurs to the muscles when you cannot use them anymore and loss of density causes them to generally weaken.more. -Loss of density causes them to generally weaken.

Mrs. Abbrazzo brought her 4-year-old daughter to the doctor, complaining that she didn't "look right." The child's forehead was enlarged, her rib cage was knobby, and her lower limbs were bent and deformed. X rays revealed very thick epiphyseal plates. Mrs. Abbruzo was advised to increase dietary amounts of viatamin D and millk and to "shoo" the girl outside to play in the sun. Considering the child's signs and symptoms, what disease do you think she has? Explain the doctor's instructions.

-Rickets result from inadequate calcification of the extracellular bone matrix, usually caused by a vitamin D deficiency. -Rickets disease of children in which the growing bones become "soft" or rubbery and are easily deformed. -Epiphyseal (growth) plates is a layer of hyaline cartilage in the metaphysics of a growing bone that consist of four zones.

Rickets, a condition of soft bones, is prevalent in Muslim countries that decree that their women wear the burka, a garment that covers all but their eyes. What is the cause and effect here?

-Skin's exposure to sunlight causes the production of Vitamin D. -Vitamin D helps with the retaining of calcium in the bones. Calcium is what makes the bones healthy and strong. -The Burka drastically reduces the amount of sunlight exposure Muslim women get, therefore decreasing their vitamin D levels and making it difficult for their bones to acquire calcium.

Dean, a 40-year-old aging beach boy, is complaining to you that although his suntan made him popular when he was young, now his face is all wrinkled, and he has several darkly pigmented moles that are growing rapidly and are as big as large coins. He shows you the moles, and immediately you think "ABCD." What does that mean and why should he be concerned?

-The ABCD rule is a method used to examine our skin for new moles or pigmented spots. ABCD stands for asymmetry, border irregularity, color, and diameter. -The 40-year-old man should be concerned due to his darkly pigmented moles. The black color violates the ABCD rule, as the mole contains several colors. -Another violation of the ABCD rule is its large-coin sized diameter. If moles are larger than a standard pencil eraser, it raises concern as a cancerous spot on the body.

You overhear some anatomy students imagining out loud what their bones would look like if they had compact bone on the inside and spongy bone on the outside, instead of the other way around. You tell them that such imaginary bones would be poorly designed mechanically and would break easily. Explain your reasoning for saying this.

-The compact lamellar structure of dense bone produces structural units designed to resist twisting and other mechanical stresses placed on bones. -Compact bone gives protection, support and resist the stresses produced by weight and movement. -Spongy bone is made up of trabeculae only a few cell layers thick containing irregularly arranged lamellae.

Mr. Miller is hospitalized for cardiac problems. Somehow, medical orders are mixed up and Mr. Miller is infused with a K+ enhanced intravenous solution meant for another patient who is taking potassium-wasting diuretics. Mr. Miller's potassium levels are normal before the IV is administered. What do you think will happen to Mr. Miller's resting membrane potentials? To his neuron's ability to generate AP's?

-The resting potential would decrease, that is, become less negative, because the concentration gradient causing net diffusion of K+ out of the cell would be smaller. -Action potentials would be fired more easily, that is, in response to smaller stimuli, because the resting potential would be closer to threshold. -Repolarization would occur more slowly because repolarization depends on net K+ diffusion from the cell and the concentration gradient driving this diffusion is lower. Also, the subsequent hyperpolarization would be smaller.

The epidermis is a keratinized stratified squamous epithelium. Explain why that epithelium is much better suited for protecting the body's external surface than a mucosa consisting of a simpler columnar epithelium would be.

-The skin is subjected to almost constant friction, which wears away the surface cells, and is charged with preventing the entry of damaging agents and with preventing water loss from the body. -A stratified squamous epithelium with its many layers is much better adapted to stand up to abrasion than is simple epithelium -Also, the stratified epithelia regenerate more efficiently than simple epithelia. -Keratin is a tough waterproofing protein that acts as a physical barrier to injurious agents. Because a mucosa is a wet membrane, it would be ineffective in preventing water loss from the deeper tissues of the body.

Victims of third-degree burns demonstrate the loss of vital functions performed by the skin. What are the two most important problems encountered clinically with such patients? Explain each in terms of the absence of skin.

-The two most important problems encountered clinically with a victim of third-degree burns are the loss of body fluids resulting in dehydration and an electrolyte imbalance; as well as the risk of infection. -Intact skin effectively blocks not only the diffusion of water and water-soluble substances out of the body, but acts as a barrier limiting the invasion of various microorganisms.

Cindy, an overweight high school student, is overheard telling her friend that she's going to research how she can transform some of her white fat to brown fat. What is her rationale here?

-White fat stores nutrients, Brown fat uses its nutrient stores to produce heat, and actually weighs less than white fat. -Brown fat occurs only in limited areas of the body, whereas white fat is found subcutanueosly anywhere in the body. -Keep in mind that brown fat is found only in infants and cannot be converted from white fat.

Muscle-relaxing drugs are administered to a patient during major surgery. Which of the two chemicals described next would be a good skeletal muscle relaxant and why? Chemical A: Binds to and blocks ACh receptors of muscle cells. Chemical B: Floods the muscle cells' cytoplasm with Ca+

Chemical A. By blocking binding of ACh to the motor end plate, neural stimulation of the cell is blocked, and the muscle cell cannot depolarize. Chemical B would actually increase contraction of the muscle cell by increasing the availability of calcium ions that bind to troponin, contributing to actin-myosin cross bridging.

As Luke fell off a ladder, he grabbed a tree branch with his right hand, but unfortunately lost his grip and fell heavily to the ground. Days later, Harry complained that his upper limb was numb. What was damaged in his fall?

Damage to the brachial plexus occurred when he suddenly stopped his fall by grabbing the branch.

As the aroma of freshly brewed coffee drifted by dozing Henry's nose, his mouth becan to water and his stomach becan to rumble. Explain his reactions in terms of ANS activity.

If we are hungry or feel the urge to eat, just the sight, smell or thought of food will cause our digestive system to signal the brain to get all systems prepared for the entry of food. This causes the muscles that line the stomach and intestines to start moving and release digestive fluids, which in turn interact with the air and fermented gas floating inside our intestinal system.

Henri, a chef in a five-star French restaurant, has been diagnosed with leukemia. He is about to undergo chemotherapy, which will kill rapidly dividing cells in his body. He needs to continue working between bouts of chemotherapy. What consequences of chemotherapy would you predict that might affect his job as a chef?

In addition to nausea and fatigue, the chemotherapy could affect his sense of taste.

Mary Morgan has just been brought into the emergency room of City General Hospital. She is perspiring profusely and is breathing rapidly and irregularly. Her breath smells like acetone (sweet and fruity), and her blood glucose tests out at 650 mg/100 ml of blood. She is in acidosis. What hormone should be administered, and why?

Insulin should be administered because symptoms are indicative of diabetic shock.

Local anesthetics block voltage-gated Na+ channels. General anesthetics are thought to activate chemically gated Cl- channels, thereby rendering the nervous system quiescent while surgery is performed. What specific process do anesthetics impair, and how does this interfere with nerve impulse transmission?

Local anesthetics such as novocaine and sedatives affect the neural processes usually at the nodes of Ranvier, by reducing the membrane permeability to sodium ions.

John sustained a severe injury during football practice & is told that he has a torn knee cartilage. Can he expect a quick, uneventful recovery? Why?

No. Cartilage heals slowly because it lacks the blood supply necessary for the healing process.

Jim Fitch decided that his physique left much to be desired, so he joined a local health club and began to "pump iron" three times weekly. After three months of training, during which he lifted increasingly heavier weights, he noticed that his arm and chest muscles were substantially larger. Explain the structural and functional basis of these changes.

Regular resistance exercise leads to increased muscle strength by causing muscle cells to hypertrophy, or increase in size. The number of myofilaments increases in these muscles.

You've just attended a football a game with your friend, Sharon, who is diabetic. While Sharon drank only one beer during the game, she is having walking straight, her speech is slurred, and she is not making sense. What does it mean when we say Sharon is diabetic? What is the most likely explanation for Sharon's current behaviour? How could you help her?

She has insufficient insulin action in her body, and she is experiencing hypoglycemia. You could help her by making sure she immediately ingests a sugary snack or drink

A model is concerned about a new scar on her abdomen. She tells her surgeon that there is practically no scar from the appendix operation done when she was 16, but this new gallbladder scar is "gross." Her appendectomy scar is small and obliquely located on the inferior abdominal surface—it is very indistinct. By contrast, the gallbladder scar is large and lumpy and runs at right angles to the central axis of the body trunk. Can you explain why the scars are so different?

The appendectomy incision ran parallel to the less dense "lines of cleavage" that separate bundles of collagen fiber in the dermis. The gallbladder incision cut across them.

Michael is answering a series of questions dealing with skeletal muscle cell excitation and contraction. In response to "What protein changes shape when Ca+ binds to it?" he writes "tropomyosin". What should he have responded and what is the result of that calcium ion binding?

The calcium actually binds to troponin, which changes shape and moves the tropomyosin to expose the myosin head binding sites.

Johnny, a 5-year-old boy, has been growing by leaps and bounds; his height is 100% above normal range for age. He has been complaining of headaches and vision problems. A CT scan reveals a large pituitary tumor. (a) What hormone is being secreted in excess? (b) What condition will Johnny exhibit if corrective measures are not taken?

The hypersecreted hormone is growth hormone. The disorder is gigantism.

Mr. Frank, a former stroke victim who had made a remarkable recovery, suddenly began to have problems reading. He complained of seeing double and also had problems navigating steps. He was unable to move his left eye downward and laterally. What cranial nerve was the site of lesion? (Right or left?)

The left trochlear nerve (IV), which innervates the superior oblique muscle responsible for this action.

Five-year-old Amy wakes her parents up at 3 AM crying and complaining of a sore neck, a severed headache, and feeling sick to her stomach. She has a temperature of 40 degrees C (104 degrees F) and hides her eyes, saying that the lights are too bright. The emergency physician suspects meningitis and performs a lumbar tap. Using your knowledge of neuroanatomy, explain into which space and at what level of the vertebral column the needle will be inserted to perform this test. Which fluid is being obtained and why?

The needle will be inserted in the lumbar area of the vertebral column below L2. The needle will be inserted into the subarachnoid space to withdraw cerebrospinal fluid to be tested for the presence of pathogens.

When a suicide victim was found, the coroner was unable to remove the drug vial clutched in his hand. Explain the reasons for this. If the victim had been discovered three days later, would the coroner have had the same difficulty? Explain.

The reason for the tightness is rigor mortis. -The myosin cross bridges are "locked on" to the actin because of the lack of ATP necessary for release. -No, peak rigidity occurs at 12 hours and then gradually dissipates over the next 48 to 60 hours as biological molecules begin to degrade.

Fumiko, a 19-year-old nursing student, had had a runny nose and sore throat for several days. Upon waking, her face felt "twisted." When she examined her face in the mirror, she noticed that the right side looked "droopy" and she was unable to move the facial muscles on that side. This made it difficult to eat or speak clearly. Which cranial nerve was affected and on which side?

The right facial nerve was affected. This condition is called Bell's palsy

You are at a party at Mary's house. After you are blindfolded, an object (a key or a rabbit's foot) is placed in your hand. What spinal tracts carry the signals to the cortex that allow you to differentiate between these objects, and what aspects of sensory perception are operating?

The specific ascending pathways of the fasciculus cuneatus carry discriminatory touch information from the upper limbs to the cortex. You must use feature abstraction and possibly pattern recognition to identify a specific pattern feature such as the teeth of a key or the fur of a rabbit's foot.

Mr Jake was admitted to the hospital with excruciating pain in his left shoulder and arm. He was found to have suffered a heart attack. Explain the phenomenon of referred pain as exhibited by Mr Jake.

Visceral pain afferents travel along the same pathways as somatic pain fibers. Pain stimuli arising in one part of the body are perceived as coming from another part. -The same spinal segments (T1-T5) innervate both the heart and arm, the brain interprets these inputs as coming from the more common somatic pathway.