test part 2

A 70-year-old woman's family physician has recommended she take a vitamin D supplement. The woman states that she tries hard to take as few pills as possible and questions her physician on the rationale and necessity for the supplementation. How can the physician most accurately reply to the patient's concerns?

"Vitamin D is important in order for your body to absorb the calcium that you consume in your diet

The resting membrane potential of a skeletal muscle was about −70 millivolts before dehydration occurred. What is the resting membrane potential of a skeletal muscle after dehydration occurred, assuming no change in membrane conductance or intracellular concentrations of Na+ or K+ .

-70

What factors affect nerve conduction velocity and what effect do they have

1- increasing fiber diameter increases nerve conduction velocity. 2. increasing inward current by increasing the axon diameter (larger axon, larger membrane area, more ion channels) 3- increasing myelination (more myelin more ion channels are concentrated in the nodes of Ranvier) increases nerve conduction velocity.

Which of the following represents the correct temporal order of events for skeletal muscle?

1.Nerve action potential 2.End plate potential 3.Muscle action potential

The troponin/tropomyosin complex is associated directly with which of the following filaments?

Actin

osteoblast

Bone Formation

Osteoclast

Bone cell responsible for resorbtion

A client asks the nurse if drinking more milk will prevent the release of calcium from her bones. The best response by the nurse would be that the release of calcium from the bone into the extracellular fluid is regulated by:

Calcitonin

A physiology experiment is conducted in which a skeletal muscle twitch is initiated with an electrical stimulator. Which factor contributes to the termination of a typical skeletal muscle twitch?

Calcium uptake by sarcoplasmic reticulum

Which of the following is an aspect of the bone growth and development that occurs during the first 2 decades of life?

Cartilage cells at the metaphyseal end of the bone plate are replaced by bone cells.

A 56-year-old woman is referred to the neurology clinic for evaluation of her long-term problem of a stumbling gait and a tendency to fall. Her visual acuity also seems to change periodically. Neurological findings suggest multiple sclerosis. This diagnosis is further supported by magnetic resonance imaging, which shows of areas of demyelination in the central nervous system. Other tests show the presence of oligoclonal bands in the spinal fluid. The loss of myelin from a nerve fiber has which of the following effects?

Decreased conduction velocity of action potential or no action potential

An 80-year-old female with a diagnosis of osteoporosis receives daily supplements of calcitonin in the form of a nasal spray that she instills each morning. expected results

Decreased bone resorption Decreased serum calcium level

When a 4-year-old boy stands erect with his medial malleoli touching, the distance between his knees is 2 inches. What is the child's most likely diagnosis and treatment?

Genu varum, which can be treated by bracing

A 42-year-old woman decides to lose weight on a diet prescribed by an anorexic friend. She loses about 30 pounds in 45 days, but her serum potassium level falls to 2.1 mmol/L (normal: 3.5 to 5.0 mmol/L). Which of the following changes is most likely to occur in this young woman?

Hyperpolarization of the resting membrane potential.

The neurotoxic venom of the black widow spider (i.e., latrotoxin or latrophilin) can increase the flux of calcium ions into the presynaptic terminal. What is the likely outcome of a black widow spider bite?

Increased acetylcholine release from nerve terminals

A 24-year-old medical student goes to the local gym to lift weights. She begins by bench-pressing 100 pounds as a warm-up procedure and then gradually increases the weight. Which of the following occurs as she adds more weight?

Increased frequency of motor nerve action potentials

An end plate potential in skeletal muscle could theoretically be generated by a decrease in permeability to which of the following ions?

K+

A 23-year-old man loses consciousness while driving, hits a tree, and dies within 15 minutes. The police find his stiff body 5 hours later. Rigor mortis is caused by a decrease in which of the following?

Muscle adenosine triphosphate levels

Skeletal muscle and cardiac muscle contract when calcium binds to which structure or molecule?

Troponin

The intracellular concentration of ion Z is 100 mEq/L, and the extracellular concentration is 5 mEq/L. The molecular weight of molecule Z is approximately 40 daltons. This relatively high intracellular concentration of molecule Z is best explained by which of the following?

Primary active transport

A 16-month-old boy has a normal weight for his age but a height far below the normal range. His list of symptoms includes a protruding abdomen, lethargy, bowlegs, muscle weakness, and irritability. His teeth have not yet developed and he has difficulty standing. What is the child's most likely diagnosis?

Rickets

ENa+ = +61 mV E K+ = −94 mV E Cl− = −72 mV set at 85

Sodium Inward Potassium Outward Chloride Outward

The threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential. Threshold potentials are necessary to regulate and propagate signaling in both the central nervous system (CNS) and the peripheral nervous system (PNS).

T

DHP

Voltage dependent L type calcium senses depolarization

RYR

Voltage dependent intracellular open and release Ca2+ from sr to cytoplasm

Osteocyte

bone cell formed when it become minerlized

The suspected pathogen is botulism (Clostridium botulinum). The surviving patients begin improving soon after receiving the only treatment available, E antitoxin. The deadly effect of botulinum toxin results from which of the following?

decreased release of acetylcholine

Alpha (α) motor neurons innervate what

extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their contraction

gamma motor neurons innervate

intrafusal fibers of skeletal muscle and are responsible to maintain the contraction