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Lecture 2 Essential Functions for Sustaining Life
Aug 26, 2024
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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.
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