Muscle Characteristics and Functions Quiz

Muscle Characteristics and Functions

• Smooth and cardiac muscles are both involuntary.
• Extensibility is the ability of a muscle to be stretched.
• Elasticity is the ability of a muscle to stretch and return to its original position.
• Perimysium wraps around muscle fascicles.
• Epimysium wraps around the entire muscle.
• A sarcomere is the segment from Z-disc to Z-disc.
• Calcium is stored in the sarcoplasmic reticulum.
• Acetylcholine is the neurotransmitter released at the neuromuscular junction.
• The power stroke occurs when actin slides towards the M-line, interacting with myosin.
• Oxygen provides the longest-lasting energy source for muscle contraction.
• Aerobic respiration requires oxygen; anaerobic respiration does not.
• Energy sources from least to greatest duration: Creatine phosphate, Anaerobic respiration, Aerobic respiration.
• Creatine phosphate provides the least energy (15-20 seconds).

Muscle Contraction Types

• Concentric contractions involve muscle shortening.
• Eccentric contractions involve muscle elongation.
• Isometric contractions involve holding a muscle at a constant length (e.g., holding a weight).

Muscle Shapes and Locations

• Orbicularis muscles (orbicularis oris, orbicularis oculi) surround the mouth and eyes, respectively.
• Rhomboid major is in a diamond shape.

Muscle Structure and Movement

• The origin of a muscle is the stationary point.
• The insertion of a muscle is the moving point, which moves towards the origin.

Nervous System Branches

• Efferent neurons take information away from the central nervous system.
• Afferent neurons take information towards the central nervous system.

Cellular Channels

• Cellular membranes have different types of channels including:
  • Voltage-gated channels respond to voltage changes.
  • Ligand-gated channels respond to chemical signals.
  • Mechanically gated channels respond to physical forces.
  • Leaky channels are always open, maintaining resting membrane potential.

Nervous System Structures

• The central nervous system comprises the brain and spinal cord.

Rotator Cuff Muscles

• The rotator cuff muscles are supraspinatus, infraspinatus, teres minor, and subscapularis.

Tissues Requiring Electrical Excitability

• Neurons and muscles need to be electrically excitable.

Muscle Groups

• The hamstrings include biceps femoris, semitendinosus, and semimembranosus.
• The quadriceps include rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.

Muscle Functions

• Cardiac muscle pumps blood throughout the heart.
• Smooth muscle functions in digestion, circulation, waste elimination, nutrient transport, sphincter closure (among other functions).
• Skeletal muscle protects organs, moves limbs, stores fat, maintains posture and stability, regulates body temperature, and controls blood glucose levels.