Muscle Anatomy and Histology Flashcards

Flashcards on muscle anatomy and histology based on lecture notes.

What is the meaning of 'Musculus' in Latin and what does it resemble?

Little mouse; resembles a mouse with tendon representing a tail.

What is the general function of muscle tissue?

Designed for movements via contractile tissue.

What are muscle cells known as?

Muscle fibers or myocytes.

Name the three types of muscle tissue based on striations.

Striated, Non-striated, and Cardiac.

What are the three types of muscles?

Skeletal muscle, Cardiac muscle, and Smooth muscle.

Where are skeletal muscles typically found?

Attached to bones & cartilages (limbs, body wall), tongue, pharynx etc.

What are other names for Skeletal Muscle?

Striped/striated and Somatic/Voluntary muscle.

What type of nerves innervate skeletal muscles?

Somatic (motor) nerves.

Describe the shape and nuclei of skeletal muscle fibers.

Elongated, not branched, multinucleated with peripherally placed nuclei.

What are the three connective tissue layers found in skeletal muscle?

Endomysium, Perimysium, and Epimysium.

What does the sarcoplasm of muscle fibers contain, and what are they composed of?

Myofibrils composed of myofilaments/myoproteins.

Name the two contractile protein filaments found in muscle fibers.

Actin (thin) & Myosin (thick).

What creates the striations seen in skeletal muscle?

Actin and Myosin filaments create the striations with alternate dark (A) and light (I) bands

What type of nerves supply skeletal muscles?

Somatic nerves.

What is the function of motor nerves in skeletal muscle?

Derived from spinal cord – for contraction.

What is the function of sensory nerves in skeletal muscle?

Derived from muscle spindles- proprioception (state of contraction, position, injury, fatigue etc..).

Define muscle tone.

Normal state of contraction of muscle even at rest.

What condition results from damage to the motor supply of a muscle?

Paralysis – loss of power to produce movement.

Define muscular spasm.

Spontaneous/involuntary contraction, may be caused by muscle pull.

What is Hyperplasia?

Addition of new muscle fiber (regeneration).

What is Hypertrophy?

Excessive use of particular muscle – increase in their size

Give examples for common sites for IM injections.

Deltoid, gluteus

Where are smooth muscles typically found?

In viscera (e.g., stomach, intestine, uterus, blood vessels).

What type of nerves innervate smooth muscles?

Autonomic nerves (sympathetic and parasympathetic nerves).

Why do smooth muscles lack striations?

Myofilaments (actin and myosin) not orderly arranged so lacks sarcomeres.

Describe the shape and nuclei of smooth muscle fibers.

Spindle shaped with centrally placed single nucleus.

How do smooth muscles contract?

Exhibit Slow but sustained contractions – do not get fatigued

Where is cardiac muscle found?

Wall of the heart.

What are intercalated discs?

Branched muscle fibers that anastomoses with neighbouring fibers

Describe the nuclei of cardiac muscle fibers.

Each fiber has centrally placed single nucleus.

What is the nervous supply to cardiac muscle?

Autonomic nerves.

describe the effects of sympathetic and parasympathetic nerves on the heart?

Sympathetic increases rate & force and Parasympathetic decreases rate & force.

Can cardiac muscle regenerate?

No regeneration – once dead no replacement.

What happens during a myocardial infarction (MI)?

Blood flow to the heart muscle is blocked, and cardiac muscle cells damage and start to die (infarct).