Muscular System

What are the three types of muscle tissue?

Skeletal muscle, Cardiac muscle, Smooth muscle.

What ability does all muscle types exhibit?

Excitability - the ability of a cell to respond to a stimulus by changing its electrical state.

What is the resting state of muscle cells called?

Polarized state.

What happens when muscle cells are stimulated?

They become depolarized and generate an action potential.

What are sarcomeres?

Repeating units of proteins in skeletal muscle that give it a striated appearance.

Describe the appearance of skeletal muscle.

Long fibers, multinucleated, and striated.

How is cardiac muscle different from skeletal muscle?

Cardiac muscle has shorter fibers, usually 1–2 nuclei, and intercalated discs.

What is the main characteristic of smooth muscle fibers?

Spindle-shaped with a single nucleus and no sarcomeres.

What is the control type for skeletal muscle?

Voluntary control.

What are the functions of skeletal muscle?

Produce and stop movement, protect internal organs, control openings, and generate heat.

What is a unique structural feature of cardiac muscle?

Intercalated discs.

What is the speed of contraction for skeletal muscle?

Fast and precise.

How does smooth muscle appear under a microscope?

Non-striated and spindle-shaped.

What involuntary control does smooth muscle have?

It automatically contracts without conscious effort.

What lab test indicates muscle damage?

Creatine Kinase (CK) levels.

What does a rise in troponin levels signify?

Marker for cardiac muscle damage, such as in a heart attack.

What does an Electrocardiogram (ECG) record?

The electrical activity of cardiac muscle.

Define muscular dystrophy.

A genetic disorder characterized by progressive skeletal muscle weakness.

What does elevated CK indicate in muscular dystrophy?

Muscle breakdown.

What is rhabdomyolysis?

Rapid breakdown of skeletal muscle due to trauma, extreme exercise, or drug toxicity.

What lab finding is associated with myocardial infarction?

Elevated troponin and abnormal ECG.

What is myositis?

Inflammation of muscle, either autoimmune or infectious.

What is myopathy?

A disease of muscle.

What does sarcolemma refer to?

The muscle cell membrane.

What are the special features of cardiac muscle?

Intercalated discs that connect heart cells.

How does smooth muscle function in the body?

Controls walls of hollow organs and vessels automatically.

Why are skeletal muscles essential for posture?

They produce resistance against gravity.

What muscle type is involuntary and non-striated?

Smooth muscle.

How are cardiac muscle cells structured?

Short, branched fibers with 1–2 centrally located nuclei.

What signifies the electrical activity of the heart?

Electrocardiogram (ECG).

What is the contraction characteristic of smooth muscle?

Slow and sustained.

What is the control type of cardiac muscle?

Involuntary control.

What type of muscle is responsible for voluntary movement?

Skeletal muscle.

List one function of smooth muscle.

Contracts to help move substances through hollow organs.

What are the locations where smooth muscle is found?

Walls of hollow organs, blood vessels, and respiratory tracts.

What does the stretch-relaxation response refer to?

The ability of smooth muscle to stretch and then relax.

What distinguishes striated from non-striated muscle?

Striated muscle has sarcomeres; non-striated muscle does not.

What is the function of skeletal muscles besides movement?

Generating heat for homeostasis.

What are the typical findings for rhabdomyolysis?

Very high CK and myoglobin in urine.

What role do intercalated discs play in cardiac muscle?

Enable communication between heart cells for coordinated contraction.

Which lab test is most specific for diagnosing a heart attack?

Troponin.

What is the primary characteristic of skeletal muscle fibers?

They are multinucleated.

What distinguishes skeletal muscle in terms of control?

It is under voluntary control.

What type of muscle can be found in the bladder?

Smooth muscle.

What is a common characteristic of cardiac muscle contraction?

Rhythmic and involuntary.

How are the nuclei of smooth muscle fibers positioned?

Single, centrally located nucleus.

What type of muscle shows a striped appearance?

Both skeletal and cardiac muscle.

What is the role of the arrector pili muscle?

Causes goosebumps in the skin.

List one lab finding for myositis.

Elevated CK and inflammatory markers.

What is one major difference between cardiac and skeletal muscles?

Cardiac muscle has intercalated discs, while skeletal muscle does not.

What are gap junctions?

Specialized connections that allow cells to communicate; found in cardiac muscle.

What is a general characteristic of all muscle types?

They respond to stimuli by contracting.

What type of contractions do smooth muscles perform?

Slow and sustained.

What is the term for the breakdown of striated muscle?

Rhabdomyolysis.

Give an example of where you would find smooth muscle.

In the stomach or blood vessels.

What is the primary function of intercalated discs?

They connect cardiac muscle cells and coordinate contractions.