MCAT Biology : MCAT Biological Sciences

Study concepts, example questions & explanations for MCAT Biology

varsity tutors app store varsity tutors android store

Example Questions

Example Question #52 : Musculoskeletal System And Muscle Tissue

Which answer correctly mactches an organ or structure with the type of muscle found there?

Possible Answers:

The stomach—cardiac muscle

The heart—skeletal muscle

The aorta—cardiac muscle

The bladder—smooth muscle

The small intestine—skeletal muscle

Correct answer:

The bladder—smooth muscle

Explanation:

Smooth muscle is found is the bladder, intestines, blood vessels, and a lot of other places that have involuntary motion. Skeletal muscle connects bones and muscles and allows us to move things voluntarily. Cardiac muscle is found in one place—the heart; therefore, the only correct match is the bladder to smooth muscle.

Example Question #1 : Types Of Muscle Cells

How many different types of muscle tissue are there in the human body?

Possible Answers:

Four

Three

None of these

Two

One

Correct answer:

Three

Explanation:

There are three classifications of muscle tissue: skeletal, cardiac, and smooth. A major distinction between these groups is that only skeletal muscle can be voluntarily controlled. Smooth muscle (such as that around blood vessels) and cardiac muscle (in the heart) are not consciously controlled. Each muscle type is unique to its specific function.

Example Question #251 : Biology

Which muscle tissue type allows for voluntary control?

Possible Answers:

None of these

Skeletal

Smooth

Cardiac

Rough

Correct answer:

Skeletal

Explanation:

Skeletal muscle is the only tissue type that allows for voluntary control; cardiac and smooth do not. Unlike the muscles in your arm, you cannot simply will the other muscle types to work. Think about it: you cannot stop your heart from pumping simply by trying to.

Example Question #261 : Biology

Striations are alternating light and dark bands seen in muscle cells under a microscope. What type of muscle tissue does not have striations?

Possible Answers:

Smooth

None of these

Skeletal

Cardiac

All of these

Correct answer:

Smooth

Explanation:

Smooth muscle is the only muscle type that does not have striations. Striated muscle cells can contract rapidly, but cannot sustain this activity for long. Smooth muscle, however, uses slow contractions and is resistant to fatigue from repetitive work.

Example Question #262 : Biology

Which muscle tissue type has the most nuclei per fiber?

Possible Answers:

All of these

None of these

Skeletal

Cardiac

Smooth

Correct answer:

Skeletal

Explanation:

Skeletal muscle tissue has the most nuclei out of the different types. Cardiac has one or two nuclei per fiber, and smooth muscle cells only have one. This is because of the high metabolic demands of these cells. There is a constant need for protein production and repairs to maintain muscle tissue, processes which originate in the nucleus. It makes sense that skeletal muscle, which is most active and has the highest energy demands, has the greatest number of nuclei.

Example Question #1 : Types Of Muscle Cells

There are 3 types of muscle: skeletal, smooth, and cardiac.

Which of these muscle types can humans control voluntarily?

Possible Answers:

All 3 muscle types can be fully controlled

Skeletal and cardiac muscle

Cardiac and smooth muscle

Smooth muscle

Skeletal muscle

Correct answer:

Skeletal muscle

Explanation:

Skeletal muscle is the only type of muscle that can be controlled voluntarily. Skeletal muscle is the muscle type used to control the movement of our bones (and therefore our bodies). An exception to this rule is that smooth muscle can be controlled by some individuals, but to a extremely limited capacity. 

Example Question #2 : Types Of Muscle Cells

Which of the following statements is true about the three muscle types?

Possible Answers:

Only one type uses the sarcomere as the functional unit.

All muscle types have mutlinucleated cells.

Only one type is controlled voluntarily.

All muscle types require calcium in order to contract.

Correct answer:

Only one type is controlled voluntarily.

Explanation:

The only type of muscle tissue that can be controlled voluntarily is skeletal muscle tissue. Both skeletal and cardiac muscle tissue have the sarcomere as the functional unit, and only skeletal muscle has multinucleated cells. Smooth muscle does not have troponin, and therefore does not require calcium in order to contract.

Example Question #1 : Types Of Muscle Cells

Which of the three muscle types is both striated and multinucleated?

Possible Answers:

Skeletal muscle

Both skeletal and cardiac muscle are striated and multinucleated

Cardiac muscle

Smooth muscle

Correct answer:

Skeletal muscle

Explanation:

The first requirement of this question is that the muscle type be striated. Striated muscle can be identified by the presence of alternating dark and light bands, caused by the repetition of sarcomeres, the basic muscle units composed of actin and myosin. Both cardiac and skeletal muscle types are striated.

The second requirement is that the muscle type must be multinucleate, meaning that individual cells have fused to form larger units with more than one nucleus. The only muscles with multinucleate cells are skeletal muscles, so that is our solution.

Example Question #3 : Types Of Muscle Cells

Skeletal muscle and cardiac muscle are similar in that they both __________.

Possible Answers:

are striated

have intercalated discs

are multinucleated cells

are attached to bone

Correct answer:

are striated

Explanation:

Cardiac muscle and skeletal muscle are both composed of sarcomeres. This layout gives both muscle types a striated appearance, alternating dark bands of myosin with lighter bands of actin. Only cardiac muscle has intercalated discs and skeletal muscle is the only type that is multinucleated. No muscle type is attached directly to bone, but skeletal muscle is linked to bone via tendons.

Example Question #1 : Types Of Muscle Cells

All of the following are characteristics of cardiac muscle except __________.

Possible Answers:

electrical synapses between nerve and muscle fibers

striated appearance

autonomic regulation

use of calcium

Correct answer:

electrical synapses between nerve and muscle fibers

Explanation:

Cardiac muscle is organized into sarcomeres, giving it a striated appearance, and cardiac contraction is strongly dependent on calcium concentrations and release. While the heart is capable of beating without nervous innervation, autonomic regulation via the parasympathetic nervous system mediates the frequency of cardiac stimulation from the sinoatrial (SA) node.

Signals from the parasympathetic nervous system travel to the cardiac muscle via chemical synapses, by use of a neurotransmitter. Signals from one cardiac fiber to another are transmitted via electrical synapses, or gap junctions, the allow proliferation of the signal without a chemical intermediate.

Learning Tools by Varsity Tutors