Muscle tissue Flashcards
What is voluntary muscle?
skeletal
What is involuntary muscle?
Smooth and cardiac
What structure is voluntary muscle?
Striated
What structure is involuntary muscle?
Started or non-striated.
The subconscious movements to maintain posture and balance is made by what muscle?
skeletal
Describe the structure of skeletal muscle.
Unbranched.
Nuclei on periphery.
Myofibrils create striated appearance.
Describe the layers of connective tissue around skeletal muscle.
Endomysium: Surrounds a single fibre.
Perimysium: Surrounds the group of fibres.
Epimysium: Surrounds the entire muscle.
What are myofibrils separated by?
Sarcoplasm.
What kind of muscle is the sarcoplasmic reticulum present in?
Striated (cardiac and skeletal)
Under the microscope; how does myosin appear?
Thicker and darker
Under the microscope; how does actin appear?
Thinner and lighter
What divides each myofilament into contractile units called sarcomeres?
Z lines.
What is the chemical messenger at neuromuscular junctions?
Acetylcholine
What is the structure of cardiac muscle?
Branched
Cylindrical
1/2 Central nuclei
Striated
What are the similarities between skeletal and cardiac muscle?
Both have sliding filament mechanism and sarcoplasmic reticulum.
What are the differences between cardiac and skeletal muscle?
Cardiac slowly leaks Ca. (Allows ventricular filling)
Have intercalated disks. (allows wave-like contraction)
Explain the conducting system of the heart.
Pulse initiated at the sinoatrial node.
Both atria contract.
The pulse then travels to the atrioventricular node.
Travels to the bundle of His.
Travels to the purkinje fibres and cardiac muscle.
Ventricles contract.
What does the modified cardiac muscle of the conducting system not have?
Intercalated discs.
T tubules.
what is the structure of smooth muscle?
Spindle shaped with tapered ends.
No striations.
Single central nuclei.
Is there actin and myosin in smooth muscle?
Yes
What is smooth muscle modulated by?
The autonomic nervous system and hormones.
What are the peristalsis pacemakers called?
Interstitial cells of cajal.
