Human Anatomy & Physiology (HAP): Illustrated Medical Notes

Chapter 1: The Human Cell & Cellular Transport

The cell is the basic structural, functional, and biological unit of all known living organisms. The cell membrane exhibits selective permeability based on the Fluid Mosaic Model.

1.1 Transport Mechanisms

• Passive Diffusion: Net movement of solutes down a concentration gradient without expenditure of ATP.
• Facilitated Diffusion: Carrier-protein assisted movement of large or polar molecules (e.g., GLUT transporters for Glucose).
• Active Transport: Movement of ions against an electrochemical gradient mediated by ATP-hydrolyzing pumps (e.g., Na⁺/K⁺-ATPase pump pumping 3 Na⁺ out and 2 K⁺ in per ATP).

Chapter 2: Blood and Hemopoiesis

Blood is a liquid connective tissue consisting of cellular elements (erythrocytes, leukocytes, thrombocytes) suspended in liquid plasma.

Erythropoiesis & Hemoglobin Synthesis:

Red blood cell production takes place in the red bone marrow under the regulation of the glycoprotein hormone Erythropoietin secreted by renal peritubular interstitial cells in response to hypoxia.