Smooth Muscles Physiology

Question 1

Which of the following is NOT a property of smooth muscles?
a) Involuntary
b) Striated
c) Non-fatigable
d) Slow to contract

Answer 1

Striated

Question 2

Smooth muscles are found in which of the following organs?
a) Heart
b) Skeletal muscles
c) Stomach
d) Biceps

Answer 2

Smooth

Question 3

Smooth muscles are controlled by which of the following nervous systems?
a) Somatic nervous system
b) Autonomic nervous system
c) Central nervous system
d) None of the above

Answer 3

Autonomic nervous system

Question 4

Smooth muscles are characterized by which of the following shapes?
a) Circular
b) Longitudinal
c) Both A and B
d) None of the above

Answer 4

Both A and B

Question 5

Smooth muscles are slower to contract than skeletal muscles because they lack which of the following structures?
a) Sarcomeres
b) T-tubules
c) Calcium ions
d) None of the above

Answer 5

Sarcomeres

Question 6

Which of the following is NOT a function of smooth muscles?
a) Constriction of blood vessels
b) Regulation of blood pressure
c) Movement of bones
d) Movement of food through the digestive tract

Answer 6

Movement of bones

Question 7

Smooth muscles are capable of sustained contractions because they have which of the following characteristics?
a) High fatigue resistance
b) Rapid contraction speed
c) Striations
d) None of the above

Answer 7

High fatigue resistance

Question 8

True or False: Smooth muscles are found in the walls of hollow organs such as the bladder and uterus.

Answer 8

True

Question 9

True or False: Smooth muscles are controlled by conscious thought and can be voluntarily contracted.

Answer 9

False

Question 10

Smooth muscles are ________ in shape, allowing them to contract and relax in a coordinated fashion.

Answer 10

Spindle-shaped

Question 11

Which of the following is NOT a type of smooth muscle?
a) Visceral smooth muscle
b) Multiunit smooth muscle
c) Cardiac smooth muscle
d) None of the above

Answer 11

Cardiac smooth muscle

Question 12

Multiunit smooth muscle is found in which of the following organs?
a) Blood vessels
b) Respiratory tract
c) Uterus
d) All of the above

Answer 12

Blood vessels

Question 13

Visceral smooth muscle is also known as which of the following?
a) Unitary smooth muscle
b) Single-unit smooth muscle
c) Both A and B
d) None of the above

Answer 13

Both A and B

Question 14

Multiunit smooth muscle is characterized by which of the following?
a) Each cell contracts independently
b) Cells are connected by gap junctions
c) Both A and B
d) None of the above

Answer 14

Each cell contracts independently

Question 15

Visceral smooth muscle is found in which of the following organs?
a) Stomach
b) Intestines
c) Bladder
d) All of the above

Answer 15

All of the above

Question 16

True or False: Multiunit smooth muscle is often found in organs that require precise control over contraction, such as the iris of the eye.

Answer 16

True

Question 17

Visceral smooth muscle cells are connected by gap junctions, allowing for _____________ contraction of the entire organ.

Answer 17

Coordinated

Question 18

Phasic smooth muscles are characterized by which of the following?
a) Prolonged contractions
b) Slow, sustained contractions
c) Rapid, intermittent contractions
d) None of the above

Answer 18

Rapid, intermittent contractions

Question 19

Tonic smooth muscles are characterized by which of the following?
a) Rapid, intermittent contractions
b) Slow, sustained contractions
c) Prolonged contractions
d) None of the above

Answer 19

Slow, sustained contractions

Question 20

Phasic smooth muscles are found in which of the following organs?
a) Bladder
b) Intestines
c) Uterus
d) All of the above

Answer 20

All of the above

Question 21

Phasic smooth muscles are important for propulsion and mixing of materials in the digestive tract. True or false?

Answer 21

True

Question 22

Tonic smooth muscles are important for maintaining muscle tone and controlling blood pressure. True or false?

Answer 22

True

Question 23

Phasic smooth muscles have a ___________ period between contractions, allowing for relaxation and recovery.

Answer 23

resting

Question 24

Tonic smooth muscles are able to maintain a constant ___________, even in the absence of external stimuli.

Answer 24

Contraction

Question 25

____________ release neurotransmitter into a wide synaptic cleft in the general area of the smooth muscle cells.

Answer 25

VARICOSITES

Question 26

Is smooth muscle Excitatory, Inhibitory, or Both?

Answer 26

skeletal muscle is only Excitatory!

Question 27

The main contractile protein in smooth muscle is called: a) Actin b) Myosin c) Troponin d) Tropomyosin

Answer 27

Myosin

Question 28

The activation of myosin in smooth muscle is regulated by which of the following? a) Calcium ions b) Sodium ions c) Potassium ions d) Chloride ions

Answer 28

Calcium ions

Question 29

Smooth muscle cells lack which of the following structures found in skeletal muscle cells? a) Sarcomeres b) Myofibrils c) Both A and B d) None of the above

Answer 29

Both A and B

Question 30

The activation of myosin in smooth muscle cells is regulated by the phosphorylation of a protein called ____________.

Answer 30

Myosin light chain

Question 31

The contractile mechanism in smooth muscle is primarily controlled by the autonomic nervous system. True or false?

Answer 31

True

Question 32

Smooth muscle cells are able to maintain a low level of calcium ions in the cytoplasm through the action of a protein pump called the _____________ pump. a) Calcium ATPase b) Sodium-potassium ATPase c) Chloride ATPase d) None of the above

Answer 32

Calcium ATPase

Question 33

In smooth muscle, action potentials are initiated by the influx of which ion into the cell? a) Sodium ions b) Potassium ions c) Calcium ions d) Chloride ions

Answer 33

Calcium ions

Question 34

The repolarization phase of the action potential in smooth muscle is primarily due to the efflux of which ion out of the cell? a) Sodium ions b) Potassium ions c) Calcium ions d) Chloride ions

Answer 34

Potassium ions

Question 35

The action potential in smooth muscle can be initiated by which of the following stimuli? a) Stretch b) Hormones c) Neurotransmitters d) All of the above

Answer 35

All of the above

Question 36

The initiation of an action potential in smooth muscle is often referred to as the ____________ potential.

Answer 36

Slow-wave

Question 37

The duration of spike action potential of smooth muscle is?

Answer 37

The duration of this type of action potential is 10 to 50 milliseconds.