Muscular tissue

Question 1

Muscle tissue general features

Answer 1

Consists of muscle fibres (myocytes)
Use energy from hydrolysis of ATP to generate force
As a result of contraction: provides body movements, maintains posture, generates heat, provides protection

Question 2

Skeletal

Answer 2

Usually attached to bone via tendons
Appear striated under microscope due to highly organized arrangement of myofibrils within cells
Myofibrils fill the sarcoplasm and extends entire length. Composed of thin filament (actin) and thick filament (myosin)
Multinucleate
Contraction is voluntary
Motion, posture, heat, protection
Fibres are cylindrical
Smallest: stapedius. Stabilizes smallest human bone (stapes). Prevents hyperacusis. Tympanic reflex.
Longest: Sartorius. Runs down length of thigh

Question 3

Cardiac

Answer 3

Striated
Branched
Single central nucleus
Fibres join end to end through intercalated discs (that contain desmosomes and gap junction)
Involuntary control
Only found in heart
Alternating thick and thin filaments
Purkinje fibers: specialised muscle cells that conduct electrical activity around the heart. Less myofibrils and more specialized connexins.

Question 4

Smooth

Answer 4

No striation
Located in walls of hollow internal structures e.g. interestines, blood vessels
Short, small, spindle shaped
Involuntary
Single cell nucleus
Bundles of thick and thin filaments