Muscular System and Calcium Homeostasis

These flashcards cover key concepts related to the muscular system's lever systems and the hormonal regulation of calcium homeostasis.

Lever

A rigid bar (bone) that moves on a fixed point (fulcrum/joint).

First-Class Lever

A lever system where the fulcrum is positioned between effort and load, like a seesaw.

Second-Class Lever

A lever system where the load is positioned between the fulcrum and effort, like a wheelbarrow; always provides mechanical advantage.

Third-Class Lever

A lever system where effort is applied between the fulcrum and load; most common in the body, allows for speed and high range of motion.

Parathyroid Hormone (PTH)

A hormone released when blood calcium is too low, stimulates osteoclasts to release calcium from bones.

Calcitriol

Active form of Vitamin D that increases calcium absorption in the intestines and works with PTH to raise blood calcium levels.

Calcitonin

A hormone released when blood calcium is too high, inhibits osteoclasts and helps build bone.

Calcium Homeostasis

The process by which the body maintains optimal levels of calcium in the blood, involving PTH, calcitriol, and calcitonin.

Osteoclasts

Cells that break down bone and release calcium into the bloodstream.

Osteoblasts

Cells that build bone and help in the incorporation of calcium into the bone matrix.