Skeletal Muscle Physiology

Skeletal Muscle Structure

• The structural and functional unit of a skeletal muscle is the sarcomere.

Sarcomere Characteristics

• In the relaxed state, the average length of each sarcomere is approximately 2.5 micrometers.
• Myosin filaments are situated in the sarcomere, making up the thick filaments.

Muscle Contraction

• During muscle contraction, the actin filaments slide on the myosin filaments towards the 'H' zone.

'A' Band and 'H' Zone

• The middle of the 'A' band has a light area called the 'H' zone, which is devoid of actin filaments.

Blood Plasma

• The main protein in plasma is albumin, which functions to regulate osmotic pressure and transport nutrients.

Blood Cells

• The most abundant cells in vertebrate blood are red blood cells (RBCs).

Red Blood Cell Function

• The main function of red blood cells (RBCs) is to transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs.

Blood Color

• Vertebrate blood is bright red when it is oxygenated.

Blood Fluid Composition

• The blood fluid, which constitutes 55% of blood, is composed of proteins, glucose, mineral ions, and hormones.