Chapter 8: Transport in Mammals

Introduction

• Focus on transport systems in mammals.
• Differences exist between transport systems in mammals, fish, and insects, but this chapter focuses only on mammals.

Understanding Transport Systems

• Definition: A transport system facilitates the movement of substances such as oxygen and nutrients to cells.
• Necessity: Necessary for cells to survive, especially in multicellular organisms.

Unicellular vs. Multicellular Organisms

• Unicellular Organisms:
  • Made up of one cell.
  • Oxygen can easily diffuse into the cell.
• Multicellular Organisms:
  • Made up of many cells.
  • Cells deep within the organism have difficulty receiving oxygen due to distance.

The Problem in Multicellular Organisms

• Oxygen and nutrients must diffuse through many layers, making direct diffusion insufficient.
• Challenge: How to ensure all cells receive necessary substances like oxygen.

Evolution of Transport Systems

• Development:
  • Spaces or cavitations formed within the organism.
  • Spaces filled with liquid to aid in transport.
  • Liquid contained within tubes to prevent leakage.

Components of Mammalian Transport System

1. Medium (Blood):
   • Liquid that carries substances (oxygen, nutrients).
2. Blood Vessels:
   • Contain blood and prevent it from leaking.
3. Pump (Heart):
   • Moves the blood, ensuring it reaches all cells.

Function of the Transport System

• Reduces the distance oxygen must travel to reach cells.
• Facilitates easier diffusion of oxygen and nutrients to cells.
• Allows for efficient removal of waste products.

Summary

• Without a Transport System:
  • Difficult for oxygen to diffuse into deep cells due to distance.
• With a Transport System:
  • Blood carries oxygen close to cells, minimizing diffusion distance.
• Importance:
  • Ensures cells receive necessary substances and efficiently remove wastes.