Differentiate between thin and thick filament? Differentiate between endocrine and exocrine gland?

Thin filament:
- Found in muscle cells
- Composed of actin protein
- Involved in muscle contraction
- Interacts with thick filaments to generate force

Thick filament:
- Found in muscle cells
- Composed of myosin protein
- Involved in muscle contraction
- Interacts with thin filaments to generate force

Endocrine gland:
- Secretes hormones directly into the bloodstream
- Hormones travel to target cells or organs to regulate various physiological processes
- Examples include the pituitary gland, thyroid gland, and adrenal glands

Exocrine gland:
- Secretes substances through ducts to the external environment or onto a surface
- Examples include sweat glands, salivary glands, and sebaceous glands
- Secretions may include sweat, saliva, or oil

Thin and Thick Filaments

| Feature | Thin Filament | Thick Filament |
|---|---|---|
| Composition | Actin | Myosin |
| Structure | Two intertwined strands | Long, rod-like structure |
| Diameter | 7 nm | 15 nm |
| Arrangement | Parallel to the muscle fiber | Interdigitate with thin filaments |
| Function | Provides the attachment site for myosin heads | Forms the power stroke that contracts the muscle |
| Location | Attached to Z-lines | Attached to M-lines |

Endocrine and Exocrine Glands

| Feature | Endocrine Gland | Exocrine Gland |
|---|---|---|
| Secretion | Hormones | Enzymes, mucus, or other fluids |
| Target | Distant cells or organs | Nearby cells or tissues |
| Duct | No duct | Has a duct |
| Regulation | Controlled by hormonal signals | Controlled by neural or hormonal signals |
| Examples | Pituitary gland, thyroid gland | Pancreas, salivary glands |
| Function | Regulate metabolism, growth, development | Aid in digestion, lubrication, waste elimination |