Question 1

What are the three types of muscle tissue?

Accepted Answer

The three types of muscle tissue are cardiac, smooth and skeletal. Cardiac and smooth are involuntary muscles, which perform basic bodily functions, whereas skeletal muscles move by conscious stimulation.

Question 2

Which of the following facts is not true about skeletal muscles?

Accepted Answer

All these facts are true about skeletal muscles except for C. Skeletal muscles can only be stretched up to 150% of their resting length, not up to 250%. There are over 600 different skeletal muscles in the body and they work in pairs and groups to perform movement.

Question 3

Which of the three types of muscle action has a constant speed of shortening and lengthening?

Accepted Answer

Of the three types of muscle action, the one that has a speed of shortening and lengthening that is constant is isometric muscle action. In this type of motion, the muscle is able to resist the force exerted against it, but it cannot overcome that force; therefore there is no discernible movement, but rather there is stability. This action does not cause joint movement.

Question 4

What is the correct order of structures of a muscle from smallest to largest?

Accepted Answer

The correct order of structures of a muscle from smallest to largest is: muscle fiber, endomysium, fascicles, perimysium, epimysium.

Question 5

Which muscular structure surrounds the actual muscle fiber and is responsible for depolarization of the surface of the fiber and protection and insulation of the fiber from others around it?

Accepted Answer

The sarcolemma is responsible for depolarization of the surface of the fiber and protection and insulation of the fiber from others around it. The sarcolemma is a thin membrane that connects with the endomysium and contains structures that are important for internal functions and growth.

Question 6

What part within the muscle fiber stores glycogen and myoglobin and is made up of lipids, enzymes and various types of cellular organelles?

Accepted Answer

The sarcoplasm stores glycogen and myoglobin and is made up of lipids, enzymes and cellular organelles. It is comparable to the cytoplasm in other cells, but has more specific functions. The stored glycogen is a source of energy, and the myoglobin is used for oxygen binding.

Question 7

Within the myofibril, which of the following is the lighter band that contains only actin?

Accepted Answer

The lighter band containing only actin within the myofibril is called the I band. The I band region becomes smaller during concentric muscle actions.

Question 8

Which of the following correctly describes what happens within the muscle fiber during contraction?

Accepted Answer

During muscle contraction, the myosin cross-bridges bind, actin slides over myosin and Z lines are pulled together. Myofilaments do not change in length, but the sarcomere does.

Question 9

What is the function of calcium in the muscle stimulation process?

Accepted Answer

During muscle stimulation, calcium binds with troponin, which subsequently shifts the tropomyosin off the binding sites, freeing them up for the myosin cross-bridges to attach themselves.

Question 10

Which of the following does not correctly describe fast-twitch muscles fibers?

Accepted Answer

All these statements are true of fast-twitch muscles except that they are used for aerobic exercises; rather, they are used for anaerobic ones such as spiking a volleyball. Their speed of shortening and force development is much faster than the slow-twitch muscles.

Question 11

Why are slow-twitch muscles more resistant to fatigue during exercise, thus making them better for longer duration exercises?

Accepted Answer

Slow-twitch muscles are more resistant to fatigue during exercise because they have less developed sarcoplasmic reticula, which release calcium more slowly. This causes a slower rate of ATP hydrolysis, so they do not tire as quickly.

Question 12

What is the correct name for the type of nerves that excite organ systems, such as the digestive system or the circulatory system?

Accepted Answer

Autonomic nerves excite the organ systems, such as digestive and circulatory. These effects are involuntary and are not consciously controlled. Somatic nerves are those that innervate the skeletal muscles and are voluntarily controlled.

Question 13

What part of a nerve cell allows for saltatory conduction?

Accepted Answer

The nodes of Ranvier allow for saltatory conduction. This is when an electrical impulse jumps from one node to the next as it progresses along the myelinated axon.

Question 14

What controls the process of changing membrane potential in the nerve cell membrane by allowing sodium ions to rush into the cell?

Accepted Answer

The sodium-potassium pump controls the process of changing membrane potential in the nerve cell membrane by allowing sodium ions to rush into the cell. This causes a dramatic change in voltage, which in turn causes an action potential to be conducted along the length of the axon.

Question 15

What principle is at play when the electrical threshold of the nerve cell membrane is reached, causing the propagation of the action potential?

Accepted Answer

The all-or-none principle is at play when the electrical threshold of the nerve cell membrane is reached, causing the propagation of the action potential. As the potential travels the length of the nerve, saltatory conduction occurs as the potential proceeds from one node of Ranvier to the next, all the way to its target organ or muscle.

Question 16

What is the anatomical name for the location on a muscle fiber where a nerve impulse is received?

Accepted Answer

The motor endplate is the anatomical name for the location on a muscle fiber where a nerve impulse is received. This location contains neurotransmitter receptors. Neurotransmitters bind to the muscle cell membrane and cause depolarization.

Question 17

What relays information to the central nervous system about changes in the body and limbs' positions due to muscular motions?

Accepted Answer

Proprioceptors relay information to the central nervous system about changes in the body and limbs' positions due to muscular motions. They are specialized to help maintain balance and posture and are found in the muscles, tendons and joints.

Question 18

Which part of the muscle fiber protects the muscle from injury due to excessive or rapid stretching?

Accepted Answer

Muscle spindles protect the muscle from injury due to excessive or rapid stretching. They do this via feedback to the nervous system about the speed and length of change in a muscle fiber.

Question 19

What specialized sensor is located near the musculotendinous junction and provides input regarding bodily movements or pressure?

Accepted Answer

Pacinian corpuscles are located near the musculotendinous junction and provide input regarding bodily movements or pressure. They assist in preventing muscle actions that are excessive and may cause injury.

Question 20

Which part of the muscle fiber senses changes in the tension of the muscle?

Accepted Answer

The Golgi tendon organs sense changes in the tension of the muscle. When activated, they send messages that indicate that the muscle is about to engage in dangerous action resulting from extreme tension.

Quiz 1: Anatomy and Physiology: Muscles, Nerves, Bones, and Tissues