A&P 1 Lec Exam 3 (Cody Mon)

During depolarization, which ion influxes the neuron to make the inside more positive?

• Calcium (Ca²⁺

• Chloride (Cl⁻)

• Potassium (K⁺)

• Sodium (Na⁺)

Skeletal muscle is the main muscle type responsible for the following functions except __________.

• digestion

• temperature Regulation

• digestion & childbirth

• digestion & temperature Regulation

Which of the following muscle fiber type are utilized just when maintain normal body posture?

• Type I fibers

• Type IIa fibers

• Type IIb/x fibers

• Type 3 fibers

A 34-year-old patient accidentally ingests a neurotoxin that blocks voltage-gated sodium (Na+) channels. Which of the following would most likely occur?

• Neurons cannot depolarize and fail to generate action potentials

• Resting membrane potential becomes more positive

• Potassium channels remain permanently open

• Myelin sheath degrades rapidly

Which of the following statements is true regarding muscle atrophy?

• Muscle atrophy is always a permanent effect.

• It involves an increase in muscle size, tone, and power.

• Atrophy is caused by consistent inactivation of muscles fibers.

• Physical functioning is unaffected by muscle atrophy.

In the aftermath of a snowstorm, Jimmy is outside shoveling all the snow on the driveway using a shovel. The next day, he notices his muscles are incredibly sore, and it doesn't go away until approximately two days later. What are possible explanations of this?

• muscle fatigue from shivering to stay warm

• sarcomere overuse

• microtears in the muscle

• Increased levels of lactic acid

Membrane potential is created by __________.

• excitable membranes

• the equal distribution of ions across the membrane

• the movement of only potassium

• the uneven distribution of ions across the membrane

Usain Bolt is able to run the 100-meter dash in under 10 seconds. At the tail end of his run, where is ATP being derived from?

• creatine phosphate and ADP & Aerobic respiration and Electron transport chain

• ATP directly present in muscle fibers

• creatine phosphate and ADP & ATP directly present in muscle fibers

• Aerobic respiration and Electron transport chain

Which statement best explains a major difference in how skeletal muscle and smooth muscle generate and maintain tension?

• Skeletal muscle maintains long-lasting tension using latch-bridge mechanisms, while smooth muscle cannot sustain tension without continuous ATP use.

• Smooth muscle can maintain tension for long periods with minimal ATP use due to latch-bridge mechanisms, while skeletal muscle cannot sustain tension without rapid fatigue.

• Skeletal muscle generates tension through actin–myosin interactions regulated by calmodulin, whereas smooth muscle relies on troponin-tropomyosin complexes.

• Smooth muscle tension occurs through graded recruitment of motor units, whereas skeletal muscle tension is always all-or-none.

A patient’s blood potassium (K+) serum level is severely low (hypokalemia). How might this affect their neurons?

• Resting membrane potential becomes more negative, making it harder to fire an action potential

• Resting membrane potential becomes less negative, causing overactivity

• The axon hillock is bypassed during conduction

• Sodium influx is increased during depolarization