Crucial Life Functions

Introduction

• Humans and other organisms have 6 crucial life functions to maintain life.
• Importance of maintaining boundaries between internal and external environments to prevent equilibrium.

Maintenance of Boundaries

External vs Internal Environment

• External Environment: Anything outside epithelial tissue.
• Internal Environment: Begins once substances cross epithelial barriers.
• Epithelial tissue's role is to serve as a barrier (e.g., skin, GI tract, respiratory tract).

Epithelial Tissue

• One of four primary tissue types: connective, muscle, nervous, and epithelial.
• Functions as a barrier to separate internal and external environments.
• Found in the epidermis, lining of the gut tube, respiratory tract, etc.

Metabolism

• Metabolism involves complex reactions requiring energy in the form of ATP.
• Components needed: Nutrients, enzymes, and waste removal.

Cellular Respiration

• Oxygen and glucose are required to produce ATP.
• Byproducts include CO2 and heat.

Types of Metabolic Reactions

• Catabolism: Breakdown of nutrients to release energy.
• Anabolism: Building of complex molecules using energy.
• Metabolism: Includes both catabolism and anabolism.

Responsiveness

• Ability to sense and respond to external and internal stimuli.

External Stimuli

• Includes temperature, light, sound, and pressure.

Internal Stimuli

• Blood pressure, body temperature, ion levels, blood glucose, and pH.

Importance

• Detect and correct small problems to prevent larger issues.
• Nervous and endocrine systems are key systems for responsiveness.

Movement

• Life requires motion on macro and micro scales.
• Macro Scale: Locomotion with muscles and bones.
• Micro Scale: Osmosis, diffusion, circulation, blood shunting, and intracellular trafficking.

Development and Growth

• Begins with fertilization and ends with senescence.
• Fertilization: Combination of male and female gametes to form a zygote.

Cell Addition and Growth

• Cleavage: Rapid cell division without size increase.
• Mitosis: Producing diploid cells.
• Meiosis: Producing haploid gametes.

Growth Processes

• Hyperplasia: Increase in cell number.
• Hypertrophy: Increase in cell size.

Reproduction

• Allows for new genetic combinations.
• Provides genetic diversity for survival against environmental changes.
• Red Queen Hypothesis: Describes the evolutionary advantage of sexual reproduction.

Environmental Requirements for Life

Oxygen

• Essential for ATP production and maintaining homeothermic temperature.
• Humans are aerobic organisms needing oxygen for basic life functions.

Oxygen Uptake

• Involves lung function and skeletal muscle activity (e.g., diaphragm, intercostal muscles).

Oxygen Distribution

• Biconcave red blood cells increase surface area for oxygen uptake.

Atmospheric Pressure

• Affects oxygen availability more than oxygen levels in different elevations.
• Atmospheric pressure decreases with elevation, affecting oxygen uptake.

Summary

• Organ systems and environmental factors are crucial for maintaining life functions.
• The body's complexity requires continuous adaptation to both internal and external changes.