103 Questions
Thin layer of connective tissue that stabilizes and surrounds muscle layers and organs
FAcia
The facia is Made up of connective fibrous tissue (like tendons and ligaments)
True
what are the three types of basic muscle found in body?
cardiac, smooth, skeletal
Which of the following is a characteristic of multi-unit smooth muscle?
It allows for independent contraction of individual muscle cells
What is the main function of visceral smooth muscle?
To regulate the diameter of blood vessels
Where is multi-unit smooth muscle typically found in the human body?
In the cilia of the eye
What is the primary role of the tunica muscularis externa in the body?
To compose the outermost layer of smooth muscle tissue
How does the contraction of smooth muscle differ from skeletal muscle?
Smooth muscle contracts slowly and continuously over extended periods, while skeletal muscle contracts rapidly and forcefully
What is the characteristic appearance of smooth muscle under a microscope?
Spindle-shaped cells with darkly staining cytoplasm and a lighter-colored nucleus
How do smooth muscle cells contract?
By sliding of actin filaments along myosin filaments
What distinguishes skeletal muscle fibers from smooth muscle cells?
Skeletal muscle fibers do not contain striations
What feature of cardiac muscle differentiates it from skeletal muscle?
Presence of intercalated discs
In smooth muscles, what gives them a firm texture?
Collagen and reticulin fibers
What distinguishes the appearance of smooth muscle cells under a microscope?
They have a uniform, non-striated appearance.
How many nuclei are typically found in a smooth muscle cell?
Smooth muscle cells are uni-nucleate, containing a single nucleus.
What initiates the contraction process in smooth muscle cells?
Calcium ions entering the cytoplasm through voltage-gated channels.
Which statement best compares smooth muscle cells to skeletal muscle cells?
Smooth muscle cells are non-striated and non-innervated, unlike skeletal muscle cells.
How does the contraction mechanism of smooth muscle cells differ from skeletal muscle cells?
Smooth muscle cells contract in a continuous, controlled manner, while skeletal muscle cells have rapid, short-lived contractions.
What is the typical number of nuclei found in a smooth muscle cell?
A single nucleus
What is the appearance of smooth muscle cells under a microscope?
Spindle-shaped and homogenous
How do smooth muscle cells contract compared to skeletal muscle cells?
Smooth muscle cells contract to a greater extent
What is the primary function of visceral smooth muscle?
To line the walls of hollow organs
How do smooth muscle contractions differ from skeletal muscle contractions?
Smooth muscle contractions are wave-like, while skeletal muscle contractions are more localized
Smooth muscle cells have a single nucleus located in the center of the cell.
True
Smooth muscle cells have a striated appearance under the microscope.
False
Smooth muscle cells can shorten to a greater extent than skeletal or cardiac muscle cells.
True
Facia is flexible and strong
True
Smooth muscle cells are typically found in large sheets or discrete groups.
True
Smooth muscle contractions are under conscious control.
False
Smooth muscle cells have a striped appearance under the microscope.
False
Smooth muscle cells typically have multiple nuclei located at the center of the cell.
False
The contraction of smooth muscle cells is more forceful when the cells are stretched.
True
Smooth muscle carry out the unconscious internal movements
True
What is the characteristic appearance of smooth muscle cells under a microscope?
Spindle-shaped with a single, centrally located nucleus
How does the contraction of smooth muscle cells differ from skeletal muscle cells?
Smooth muscle contractions are slower and more sustained compared to skeletal muscle contractions.
What initiates the contraction process in smooth muscle cells?
Hormone stimulation and stretching of the muscle cells
How does the contraction mechanism of smooth muscle cells differ from skeletal muscle cells?
Smooth muscle cells contract more forcefully when stretched, while skeletal muscle cells do not.
What distinguishes the structure of smooth muscle cells from skeletal muscle cells?
Smooth muscle cells have a spindle-shaped morphology with a single, centrally located nucleus, while skeletal muscle cells are multinucleated.
What is the primary function of peristalsis in the gastrointestinal (GI) tract?
To facilitate digestion and absorption by moving food through the tract
Which layer of muscle fibers in the GI tract is responsible for narrowing the opening and pushing food forward?
Inner circular layer
Which type of muscle lines the walls of the GI tract and other internal organs?
Smooth muscle
What drives the involuntary contractions of the GI tract?
The parasympathetic nervous system
What is the term used to describe the wave-like movements that propagate continuously throughout the GI tract, moving food from one section to another?
Peristaltic waves
During fasting, low amplitude, high frequency contractions dominate the upper GI tract, and the lower GI tract rests.
True
After a meal, a burst of propagated contractions appears, generating a strong, rapid peristaltic wave that reaches the small intestine within minutes.
True
Smooth muscle cells have a striped appearance under the microscope.
False
Peristalsis is the term used to describe the wave-like movements that propagate continuously throughout the GI tract, moving food from one section to another.
True
Smooth muscle contractions are under conscious control.
False
What characteristic appearance is seen in cardiac muscle fibers under a microscope?
Striped with alternating light and dark bands
What is the purpose of the branching structure of cardiac muscle fibers?
To allow for synchronized contraction and relaxation of the muscle fibers
How do cardiac muscle fibers surround the heart chambers?
They create a dense network of muscle cells around the chambers
How many nuclei are typically found in a cardiac muscle cell?
One nucleus per cell
Which of the following is a key feature that distinguishes cardiac muscle from skeletal muscle?
Cardiac muscle has a branching structure, while skeletal muscle does not
Intercalated discs are located between adjacent cardiomyocytes.
True
The autonomic nervous system controls contractility and heart rate through parasympathetic input from the vagus nerve only.
False
Cardiac muscle tissue ensures the heart operates effectively as a filter.
False
The structure and function of cardiac muscle are primarily dictated by the digestive system.
False
Smooth muscle cells control heart rate through sympathetic activation.
False
Which of the following statements about cardiac muscle is true?
It is capable of intrinsic contraction without external stimulation.
Where is the Sinoatrial node located?
In the heart and initiates the heart's contraction.
What is the characteristic appearance of cardiac muscle under a microscope?
Striated, with a striped appearance.
How do cardiac muscle cells form around the heart chambers?
They form a branched, interconnected network.
How many nuclei are typically found in a cardiac muscle cell?
One nucleus.
What is the primary function of the Purkinje fibers in the heart?
To rapidly transmit electrical signals to the ventricular myocardium
Which structure in the heart is considered the natural pacemaker?
The sinoatrial (SA) node
What is the key characteristic that distinguishes cardiac muscle from skeletal muscle?
Cardiac muscle contractions are inherently involuntary, ensuring continuous function without conscious effort
What is the primary role of the atrioventricular (AV) node in the heart's conduction system?
To act as a relay station, receiving and integrating electrical signals from the atria and passing them onto the bundle of His
What mechanisms ensure the proper synchronization of atrial and ventricular contractions in the heart?
Electrical connections between cardiomyocytes, gap junctions, and the electrical propagation of action potentials
Cardiac muscle operates under voluntary control.
False
The sinoatrial node is responsible for generating spontaneous electrical activity that travels to the ventricles.
True
Cardiac muscle cells have a striated appearance under the microscope.
False
The autonomic nervous system can only modulate the heart's rate through parasympathetic input from the vagus nerve.
False
The rhythm of cardiac muscle contractions is controlled solely by the inherent autorhythmicity of the heart.
False
The sinoatrial (SA) node is responsible for maintaining a steady pace for the heartbeats.
True
Cardiac muscle cells, or myocardial tissue, contain thick myosin filaments and thin actin filaments that do not slide past each other during contraction.
False
Contraction synchronization in the heart is achieved through electrical coupling between adjacent cardiomyocytes via gap junctions.
True
The Purkinje fibers transmit the signal rapidly throughout the atria, ensuring synchronous and coordinated contraction.
False
Involuntary contraction of cardiac muscle is regulated by the autonomic nervous system and voluntary control.
False
What is the point of origin for the biceps brachii muscle?
The long head originates from the supraglenoid tubercle, and the short head originates from the coracoid process
What is the point of insertion for the latissimus dorsi muscle?
The latissimus dorsi inserts onto the fifth costal cartilage, the thorax, and the iliac crest
Which of the following best describes flexion?
A movement that decreases the angle between two bones, creating a bend or bending around a joint
What is the term used to describe the attachment site of a muscle on the stable (fixed) bone connected to the joint the muscle is acting upon?
Origin
Which of the following is NOT an example of extension?
Bending the knee joint
Flexion refers to a movement that increases the angle between two body parts.
False
Extension involves straightening the arm, decreasing the angle between the humerus and radius/ulna.
False
The biceps brachii muscle is primarily active during extension of the elbow.
False
The triceps brachii muscle is active during flexion of the wrist.
False
The primary direction of force generation for a muscle is determined by the line connecting the point of origin and insertion.
True
What is the point of insertion for a muscle?
The site that undergoes most movement when the muscle contracts
What is the definition of flexion?
Bending a limb to decrease the angle between two body parts
Which of the following is the definition of extension?
Bending a limb to increase the angle between two body parts
What is the point of origin for a muscle?
The site of less movement
Which movement involves moving a body part away from the midline?
Abduction
What is the primary function of the point of insertion of a muscle?
To provide the site of most movement during muscle contraction
Which of the following movements is associated with an increase in the angle between two body parts?
Extension
Which of the following is a characteristic of the point of origin of a muscle?
It is the site of least movement during muscle contraction
How does the movement of abduction differ from the movement of adduction?
Abduction increases the angle between two body parts, while adduction decreases the angle
Which of the following is the correct definition of flexion?
A movement that decreases the angle between two body parts
The point of insertion is the site that undergoes most movement when the muscle contracts.
True
Flexion is defined as bending a limb to increase the angle between two body parts.
False
The biceps brachii muscle's point of origin is on the scapula.
True
Abduction refers to moving a body part toward the midline of the body.
False
The name of a muscle often describes its shape, location, or function.
True
Explore the thin layer of connective tissue that stabilizes and surrounds muscle layers and organs in the human body. Test your knowledge on fascia anatomy.
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