1. Unit One: Introduction to Physiology: The Cell and General Physiology
Chapter 1: Functional Organization of the Human Body and Control of the “Internal Environment”
Guyton and Hall, Textbook of Medical Physiology, 12 edition

2. 1. Cells: the living units of the body
Human Physiology
The attempt to explain the specific characteristics and
mechanisms of the human body that make it a living being.
1. Cells: the living units of the body
Each organ is an aggregate of many different cells held
together by intercellular supporting structures
All cells have certain basic characteristics
Almost all cells have the ability to reproduce

3. Extracellular Fluid—The “Internal Environment”
Intracellular Fluid-fluid within the cell
Extracellular Fluid-found in the spaces outside the cells
Constant motion throughout the body
Contains the ions and nutrients cells need
Called the “internal environment”

4. Differences Between Intracellular and Extracellular Fluids
Contains large amounts of Na+, Cl-, and bicarbonate ions
Contains nutrients such as oxygen, glucose, fatty acids,
and amino acids
Contains carbon dioxide and other cellular wastes
Intracellular Fluid:
Contains large amounts of K+, Mg+, and phosphate ions

5. Homeostatic Mechanisms
The maintenance of nearly constant conditions
in the internal environment.
Extracellular fluid transport and mixing
system:
Blood Circulatory System
Origin of nutrients in the extracellular fluid
Respiratory system
Gastrointestinal tract
Liver and other metabolic organs
Musculoskeletal system

7. Homeostatic Mechanisms (cont.)
Removal of metabolic end products
Removal of carbon dioxide by the lungs
Kidneys
GI tract and the liver
Regulation of body functions
Nervous system
Endocrine system
Protection of the body
Immune system
Integumentary system
Reproduction

8. Control Systems of the Body
Examples of control systems
Regulation of oxygen and carbon dioxide in the
extracellular fluid
Regulation of arterial blood pressure
Normal ranges and physical characteristics of
extracellular fluid components

9. Normal Value
Range
Non-lethal
Limits
Unit
Oxygen 40
35-45
mm Hg
Carbon dioxide
5-80
Sodium ion
142
mmol/L
Potassium ion
4.2
Calcium ion
1.2
Chloride ion
108
70-130
Bicarb. Ion 28
24-32
8-45
Glucose 85
75-95
mg/dl
Body Temp. 37 C
Acid-Base
7.4 pH

10. Control Systems of the Body (cont.)
Characteristics of control systems
Negative feedback
Positive feedback
Adaptive control