Lecture 2: ATMOSPHERE & hypoxia AVIATION MANAGEMENT COLLEGE SIR MOHD ‘ARIFF BIN ABDUL JALIL Lecture 2: ATMOSPHERE & hypoxia AVIATION HUMAN FACTOR: AHF 2203

Review on last chapter Definition of Physiology and Flight Physiology. Importance of Flight Physiology. Basic Concept of The Nervous System. Basic Concept of The Respiratory System. Basic Concept of The Circulatory System.

Learning Outcomes At the end of this session, student should be able to: Know that pressure plays the important role during altitude changes Classify the types of hypoxia, it causes, symptoms, and prevention steps through the explanation.

Earth’s Atmosphere Air is one of the primary things that makes life on Earth possible. Air is a synonym for atmosphere. The Earth’s atmosphere or air is made up of a variety of gases and other particles.

What is the Atmosphere?? Layer of gases surrounding the planet Earth that is retained by Earth's gravity.

Layers (Structure) of Atmosphere

Troposphere Temperature will decrease constantly with altitude. 75% of weight of atmosphere. Contains almost all weather Altitude (height) vary with: Latitude: lower at poles and higher at equatorial Seasons: higher in summer than winter Almost all clouds in this layer. Almost commercial aircrafts fly in this layer.

Stratosphere Very small increase in temperature (almost constant) except at the top where temperature is zero at 50 kms. Little water vapor @ turbulence

Functions of the Atmosphere Source of oxygen and carbon dioxide Protection for the human on the Earth from the harmful cosmic ray, solar radiation and ultraviolet (UV) ray. Source of rain Maintains the temperature and climate that sustain life on earth

Variation in Atmosphere The earth’s atmosphere varies in Temperature Pressure Density Humidity

Atmospheric Pressure Atmospheric pressure is the combined weight of all the atmospheric gases, creating a force upon the surface of the earth – the cause of this force is gravity. The atmospheric pressure can be measured in force / unit area (Pounds per square inch [Psi] or Millimeters of mercury [mm/Hg]) The standard atmospheric pressure at sea level is 760 mm/Hg.

Pressure and Temperature Decrease with Altitude Altitude (Feet) Pressure (mm/ Hg) Temperature (degree Celsius) 760 15.0 18,000 380 -5.3 34,000 190 -62.3 48,000 95 -67.3 63,000 47 -67.04

Pressure & Temperature Air Pressure At sea level, the air pressure is about 760 mm/Hg. As the altitude increases, the air pressure decreases (and there is less oxygen to breathe). Temperature As we ascend from the surface, the temperature falls steadily with altitude. Temperature decreases at about 2°C per 1,000 feet .

Physiological Zones of the Atmosphere Atmosphere can be divided into 2 physiological zones, which are efficient and deficient. Efficient zone: Sea level to 10,000 feet Deficient zone: 10,000 to 50,000 feet These zones can affect us medically and physiologically. Physiological relating to the way that living things functions

HYPOXIA

Definition of Hypoxia A condition that results from an insufficient amount of oxygen (O2) in the body. Hypoxia can occur at any altitude and it is accumulative among the types of hypoxia. Syndromes of lack of oxygen in blood Effect mainly the brain and other nervous system

WHAT WILL HAPPEN DUE TO LACK OF OXYGEN IN BLOOD? CRITICAL THINKING WHAT WILL HAPPEN DUE TO LACK OF OXYGEN IN BLOOD? WHY BRAIN IS AFFECTED THE MOST? WHAT ARE THE EFFECTS IF BRAIN IS AFFECTED?

How it can be happened?? (Physiological Process) Hemoglobin is primary transport to carry oxygen through blood. The ability of hemoglobin to carry oxygen is called as: Blood Oxygen Saturation (normally 95%- 98% at sea level). It is measurable as we ascend.

Experiment on Removing Oxygen Time of Oxygen 1 Minute 2 Minutes 3 Minutes 4 Minutes 5 Minutes 6 Minutes Put Back on Oxygen