Smooth Muscles Physiology Flashcards
Which of the following is NOT a property of smooth muscles?
a) Involuntary
b) Striated
c) Non-fatigable
d) Slow to contract
Striated
Smooth muscles are found in which of the following organs?
a) Heart
b) Skeletal muscles
c) Stomach
d) Biceps
Smooth
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
Autonomic nervous system
Smooth muscles are characterized by which of the following shapes?
a) Circular
b) Longitudinal
c) Both A and B
d) None of the above
Both A and B
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
Sarcomeres
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
Movement of bones
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
High fatigue resistance
True or False: Smooth muscles are found in the walls of hollow organs such as the bladder and uterus.
True
True or False: Smooth muscles are controlled by conscious thought and can be voluntarily contracted.
False
Smooth muscles are ________ in shape, allowing them to contract and relax in a coordinated fashion.
Spindle-shaped
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
Cardiac smooth muscle
Multiunit smooth muscle is found in which of the following organs?
a) Blood vessels
b) Respiratory tract
c) Uterus
d) All of the above
Blood vessels
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
Both A and B
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
Each cell contracts independently
Visceral smooth muscle is found in which of the following organs?
a) Stomach
b) Intestines
c) Bladder
d) All of the above
All of the above
True or False: Multiunit smooth muscle is often found in organs that require precise control over contraction, such as the iris of the eye.
True
Visceral smooth muscle cells are connected by gap junctions, allowing for _____________ contraction of the entire organ.
Coordinated
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
Rapid, intermittent contractions
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
Slow, sustained contractions
Phasic smooth muscles are found in which of the following organs?
a) Bladder
b) Intestines
c) Uterus
d) All of the above
All of the above
Phasic smooth muscles are important for propulsion and mixing of materials in the digestive tract. True or false?
True
Tonic smooth muscles are important for maintaining muscle tone and controlling blood pressure. True or false?
True
Phasic smooth muscles have a ___________ period between contractions, allowing for relaxation and recovery.
resting
Tonic smooth muscles are able to maintain a constant ___________, even in the absence of external stimuli.
Contraction
____________ release neurotransmitter into a wide synaptic cleft in the general area
of the smooth muscle cells.
VARICOSITES
Is smooth muscle Excitatory, Inhibitory, or Both?
skeletal muscle is only Excitatory!
The main contractile protein in smooth muscle is called:
a) Actin
b) Myosin
c) Troponin
d) Tropomyosin
Myosin
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
Calcium ions
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
Both A and B
The activation of myosin in smooth muscle cells is regulated by the phosphorylation of a protein called ____________.
Myosin light chain
The contractile mechanism in smooth muscle is primarily controlled by the autonomic nervous system. True or false?
True
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
Calcium ATPase
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
Calcium ions
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
Potassium ions
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
All of the above
The initiation of an action potential in smooth muscle is often referred to as the ____________ potential.
Slow-wave
The duration of spike action potential of smooth muscle is?
The duration of this type of action potential is 10 to 50 milliseconds.
