Smooth and Cardiac Muscle: Structure and Function - Histology Quiz

Question 1

Which of the following neurotransmitters is released at the neuromuscular junction in smooth muscle?

Accepted Answer

Acetylcholine

Answer

Norepinephrine

Answer

Dopamine

Answer

Serotonin

Question 2

Which of the following is the primary function of cardiac muscle?

Accepted Answer

Pumping blood

Answer

Digesting food

Answer

Moving limbs

Answer

Regulating body temperature

Question 3

Which of the following ion channels is responsible for the rapid depolarization phase of the cardiac action potential?

Accepted Answer

Fast sodium channels

Answer

Slow calcium channels

Answer

Potassium-sodium pump

Answer

Chloride-bicarbonate exchanger

Question 4

Which of the following drug classes is used to decrease heart rate?

Accepted Answer

Beta-blockers

Answer

Calcium channel blockers

Answer

Nitrates

Answer

Dopamine agonists

Question 5

Which of the following types of smooth muscle is found in the walls of blood vessels?

Accepted Answer

Visceral smooth muscle

Answer

Multi-unit smooth muscle

Answer

Cardiac smooth muscle

Answer

Skeletal smooth muscle

Question 6

Which of the following properties enables smooth muscle to maintain sustained contractions?

Accepted Answer

Low energy requirements

Answer

Abundance of mitochondria

Answer

High calcium sensitivity

Answer

Rapid action potential propagation

Question 7

What is the role of the sarcoplasmic reticulum in smooth muscle?

Accepted Answer

Calcium storage

Answer

Energy production

Answer

Ion transport

Answer

Mitochondrial biogenesis

Question 8

Cardiac muscle is primarily located in which organ of the human body?

Accepted Answer

Heart

Answer

Blood vessels

Answer

Skeletal system

Answer

Digestive tract

Question 9

Which of the following regulatory proteins plays a crucial role in smooth muscle contraction?

Accepted Answer

Myosin light chain kinase

Answer

Calmodulin

Answer

Tropomyosin

Answer

Parvalbumin

Question 10

What is the primary difference in the ultrastructure of smooth and cardiac muscle cells?

Accepted Answer

Organization of actin and myosin filaments

Answer

Presence of striations

Answer

Number of nuclei

Answer

Mitochondrial density

Question 11

What is the main function of myofilaments in cardiac muscle?

Accepted Answer

Contraction

Answer

Relaxation

Answer

Electrical impulse propagation

Answer

Energy storage

Question 12

Which of the following gives cardiac muscle its characteristic striated appearance?

Accepted Answer

Sarcomeres

Answer

Myofibrils

Answer

Mitochondria

Answer

Glycogen granules

Question 13

Which cells in the mammalian heart are responsible for initiating the heartbeat?

Accepted Answer

Conduction cells

Answer

Myocytes

Answer

Purkinje fibers

Answer

Endothelial cells

Question 14

Where in the human body is the largest population of smooth muscle found?

Accepted Answer

Gastrointestinal tract

Answer

Blood vessels

Answer

Respiratory system

Answer

Skeletal muscles

Question 15

Enhanced: Identify the characteristic feature of smooth muscle cells.

Accepted Answer

Branched nuclei

Answer

Striated appearance

Answer

Gap junctions

Answer

Thick myofilaments

Question 16

Enhanced: What is the function of the sarcoplasmic reticulum in muscle cells?

Accepted Answer

Storing calcium ions

Answer

Synthesizing myofilaments

Answer

Transmitting electrical impulses

Answer

Breaking down glucose for energy

Question 17

Enhanced: Which hormone stimulates the contraction of smooth muscle cells?

Accepted Answer

Epinephrine

Answer

Acetylcholine

Answer

Testosterone

Answer

Insulin

Question 18

Enhanced: What is the functional significance of the interaction between the thin and thick filaments in muscle cells?

Accepted Answer

Thin filaments slide over thick filaments during contraction

Answer

Thick filaments provide structural support

Answer

Thin filaments initiate the contraction process

Answer

Thick filaments store calcium ions

Question 19

Enhanced: Which type of blood vessel is lined primarily by smooth muscle?

Accepted Answer

Veins

Answer

Arteries

Answer

Capillaries

Answer

Lymphatics

Question 20

Which muscle type is primarily responsible for voluntary body movements?

Accepted Answer

Skeletal muscle

Answer

Visceral smooth muscle

Answer

Multi-unit smooth muscle

Answer

Cardiac muscle

Question 21

What is the key structural difference between smooth and cardiac muscle cells?

Accepted Answer

Presence of visible striations in cardiac muscle

Answer

Cell shape

Answer

Organization of myofibrils

Answer

Number of nuclei

Question 22

Which hormone is known to increase heart rate and contractility?

Accepted Answer

Epinephrine

Answer

Cortisol

Answer

Testosterone

Answer

Insulin

Question 23

What is the fundamental unit of contraction within cardiac muscle?

Accepted Answer

Sarcomere

Answer

Myofibril

Answer

Muscle fiber

Answer

Intercalated disc

Question 24

Which of the following is a defining characteristic of smooth muscle cells?

Accepted Answer

Spindle-shaped, centrally located nucleus

Answer

Cuboidal, centrally located nucleus

Answer

Cylindrical, multiple centrally located nuclei

Answer

Branched, peripherally located nuclei

Question 25

What is the primary function of the intercalated discs in cardiac muscle?

Accepted Answer

To facilitate electrical and mechanical coupling between adjacent cells

Answer

To provide structural support to the muscle fibers

Answer

To store calcium ions for muscle contraction

Answer

To transmit nerve impulses

Question 26

Where are gap junctions most commonly found in smooth muscle?

Accepted Answer

Along the sides of adjacent cells

Answer

At the ends of adjacent cells

Answer

Only in the central region of the cell

Answer

Gap junctions are not present in smooth muscle

Question 27

Which of the following proteins plays a critical role in the rhythmic contractions of cardiac muscle?

Accepted Answer

Troponin C

Answer

Myosin

Answer

Tropomyosin

Answer

Actin

Question 28

What is the unique characteristic of cardiac muscle that allows it to maintain a steady rhythm of contraction without external stimulation?

Accepted Answer

Autorhythmicity

Answer

Multi-nucleation

Answer

Branched fibers

Answer

Voluntary control

Question 29

Which of the following neurotransmitters is known to induce relaxation of smooth muscle?

Accepted Answer

Nitric oxide

Answer

Serotonin

Answer

Epinephrine

Answer

Acetylcholine

Question 30

What is the primary structural difference between smooth and striated muscle?

Accepted Answer

Arrangement of myofilaments

Answer

Number of nuclei per cell

Answer

Presence or absence of gap junctions

Answer

Type of neurotransmitter receptors

Question 31

Which type of muscle exhibits involuntary contractions and is found in the walls of hollow organs such as the stomach and intestines?

Accepted Answer

Smooth muscle

Answer

Cardiac muscle

Answer

Skeletal muscle

Question 32

What is the primary function of smooth muscle in the digestive system?

Accepted Answer

Peristalsis

Answer

Voluntary movement

Answer

Skeletal support

Answer

Blood pumping

Question 33

Which of the following hormones can stimulate the contraction of cardiac muscle?

Accepted Answer

Epinephrine

Answer

Insulin

Answer

Cortisol

Answer

Glucagon

Question 34

Which cellular structure is responsible for the distinctive striated appearance of cardiac muscle?

Accepted Answer

Sarcomeres

Answer

Intercalated discs

Answer

Gap junctions

Answer

T tubules

Question 35

What is the primary purpose of intercalated discs in cardiac muscle?

Accepted Answer

To facilitate rapid electrical conduction between cells

Answer

To provide mechanical support for the muscle fibers

Answer

To regulate calcium release from the sarcoplasmic reticulum

Question 36

A patient presents with a condition characterized by slow and irregular heartbeats. Which cellular feature could potentially be implicated in this condition?

Accepted Answer

Disruptions in the intercalated discs

Answer

Decreased number of sarcomeres

Answer

Increased calcium levels in the cytoplasm

Answer

Reduced acetylcholine receptors

Question 37

A patient experiencing persistent muscle spasms in the digestive tract is suspected to have a condition affecting which type of muscle?

Accepted Answer

Smooth muscle

Answer

All of the above

Answer

Cardiac muscle

Answer

Skeletal muscle

Question 38

Which of the following statements accurately describes the difference between smooth muscle and cardiac muscle?

Accepted Answer

Smooth muscle is involuntary and lacks striations, while cardiac muscle is involuntary and striated.

Answer

Smooth muscle is involuntary and striated, while cardiac muscle is involuntary and lacks striations.

Answer

Smooth muscle is voluntary and lacks striations, while cardiac muscle is involuntary and striated.

Question 39

Which of the following is a unique characteristic of cardiac muscle that contributes to its ability to maintain a consistent heart rhythm?

Accepted Answer

It has a built-in pacemaker system.

Answer

It is highly vascularized.

Answer

It can contract for extended periods without fatigue.

Answer

It is resistant to damage from prolonged exercise.

Question 40

Which of the following is a characteristic of smooth muscle cells?

Accepted Answer

Spindle-shaped and single-nucleated

Answer

Voluntary control

Answer

Branched cells with multiple nuclei

Answer

Striated appearance

Question 41

In which organ is cardiac muscle primarily found?

Accepted Answer

Heart

Answer

Blood vessels

Answer

Stomach

Answer

Lungs

Question 42

Which structure is responsible for initiating the rhythmic contractions of the heart?

Accepted Answer

Sinoatrial node

Answer

Atrioventricular node

Answer

Intercalated discs

Answer

Purkinje fibers

Question 43

Which type of muscle contraction is involuntary and sustained over time?

Accepted Answer

Tonic contraction

Answer

Phasic contraction

Answer

Isometric contraction

Answer

Clonic contraction

Question 44

Which type of gap junction is uniquely found in cardiac muscle?

Accepted Answer

Intercalated discs

Answer

Plasmodesmata

Answer

Desmosomes

Answer

Tight junctions

Question 45

What is the primary role of the sarcoplasmic reticulum in muscle cells?

Accepted Answer

Stores and releases calcium ions for muscle contraction

Answer

Provides structural support to the cells

Answer

Transmits electrical impulses

Answer

Produces energy for muscle contraction

Question 46

Which type of muscle fiber is present exclusively in the atria of the heart?

Accepted Answer

Atrial fibers

Answer

Ventricular fibers

Answer

Skeletal muscle fibers

Answer

Purkinje fibers

Question 47

Cardiomyopathy is a disease that primarily affects which type of muscle?

Accepted Answer

Cardiac muscle

Answer

Smooth muscle

Answer

Skeletal muscle

Answer

Nervous tissue

Question 48

Which imaging technique is commonly used to evaluate cardiac muscle function?

Accepted Answer

Echocardiography

Answer

X-ray

Answer

Electromyography

Answer

Magnetic resonance imaging

Question 49

Which of the following is NOT a characteristic of smooth muscle?

Accepted Answer

Striated appearance

Answer

Found in the walls of hollow organs

Answer

Slow, sustained contractions

Answer

Involuntary control

Question 50

Intercalated discs in cardiac muscle primarily facilitate:

Accepted Answer

Electrical and mechanical coupling between adjacent muscle cells

Answer

Regulation of blood flow through the heart

Answer

Structural support for the muscle fibers

Question 51

A patient presents with a gastrointestinal condition affecting smooth muscle. Which of the following symptoms is least likely to be observed?

Accepted Answer

Involuntary muscle spasms in the limbs

Answer

Difficulty swallowing

Answer

Abdominal pain

Answer

Constipation

Question 52

The arrangement of myosin and actin filaments in smooth muscle results in:

Accepted Answer

A non-striated appearance due to the diagonal orientation of the filaments

Answer

A striated appearance similar to skeletal muscle

Answer

Random distribution of filaments throughout the muscle

Question 53

What is the primary role of the sarcoplasmic reticulum in cardiac muscle?

Accepted Answer

Stores and releases calcium ions, regulating muscle contraction

Answer

Synthesizes ATP for muscle energy

Answer

Provides structural support for the muscle fibers

Question 54

Which of the following statements accurately describes the difference between smooth muscle and cardiac muscle?

Accepted Answer

Smooth muscle is involuntary and non-striated, while cardiac muscle is involuntary and striated.

Answer

Smooth muscle is involuntary and striated, while cardiac muscle is voluntary and non-striated.

Answer

Smooth muscle is voluntary and non-striated, while cardiac muscle is involuntary and striated.

Question 55

Which of the following conditions can be caused by dysfunction of smooth muscle in the bronchioles?

Accepted Answer

Asthma

Answer

Duchenne muscular dystrophy

Answer

Myasthenia gravis

Answer

Parkinson's disease

Question 56

A patient with a heart murmur is likely experiencing a problem with which of the following aspects of cardiac muscle function?

Accepted Answer

Valve function and blood flow

Answer

Contractile force generation

Answer

Electrical impulse conduction

Answer

Oxygen delivery to muscle fibers

Question 57

Which of the following factors DOES NOT contribute to the autorhythmicity of cardiac muscle?

Accepted Answer

Neural stimulation from the autonomic nervous system

Answer

Presence of specialized pacemaker cells

Answer

Gap junctions connecting muscle fibers