How does SCUBA affect the respiratory system? How does the gear work? BI 203 Human Anatomy & Physiology II

How does the behavior of fluids in different states compare? Poiseuille’s law flow = (P1 - P2) r vl Flow= P1-P2/R Properties of liquids…Properties of gases… Boyles: P1V1=P2V2 Charles: P1V1/T1 = P2V2/T2 Combined: P = nRT/V BI 203 Human Anatomy & Physiology II

Take a deep breath and try to determine: Which muscles are involved? and Are they relaxing or contracting? How do we ventilate? BI 203 Human Anatomy & Physiology II

To force air out, what has to happen to volume? Accomplished by: relaxation during quiet breathing contraction during forced breathing... 1) internal intercostals 2) abdominal muscles BI 203 Human Anatomy & Physiology II How do we ventilate (expiration)?

Air flows due to differences in pressure Pressure: P1V1 = P2V2 So…increased volume = ? Accomplished with: 1) external intercostal muscles 2) diaphragm 3) additional ones when needed How do we ventilate (inspiration)? BI 203 Human Anatomy & Physiology II

Take 5!!! Discuss with your neighbor and predict an answer With the heart, we can directly alter the pressure of the fluid by applying force to the fluid resulting in a change in pressure and volume. However, with the lungs, there is no way to directly influence the fluid pressure (air) at the point of origin. So, how do we pump air into our lungs? BI 203 Human Anatomy & Physiology II

How does SCUBA affect the respiratory system? What were the rules (1-3?) discussed by the dive instructor yesterday?

How does SCUBA affect the respiratory system? A key aspect to consider is the compressibility of gases vs. the incompressibility of liquids. Where in your body do you have air spaces? Those areas can be directly affected by changes in pressure/volume. 33 feet of water = the pressure from 1 atmosphere Pressure? 33’ 66’ 99’ BI 203 Human Anatomy & Physiology II

How does SCUBA affect the respiratory system? 33’ 66’ 99’ 33’ 66’ 99’ 33’ 66’ 99’ Effects on volumeEffects on densityEffects of equalized pressure

How does SCUBA affect the respiratory system? Pressure? 33’ 66’ 99’ When snorkeling, what happens to pressure and volume in respiratory system? BI 203 Human Anatomy & Physiology II

How does SCUBA affect the respiratory system? Pressure? 33’ 66’ 99’ When SCUBA diving and breathing at depth, then holding your breath while ascending, what happens to pressure and volume in respiratory system? BI 203 Human Anatomy & Physiology II Abyss clip

BI 203 Human Anatomy & Physiology II Are there other air spaces to consider when diving?

Henry’s Law: Concentration of a gas in a liquid depends on the the Partial pressure of the gas and the solubility of that particular gas. [O 2 ] = PO 2 * Solubility Does anything else change with pressure? 33’ 66’ 99’ What is P N2 ? (760)(4)(.79) = 2402 What is P N2 ? (760)(1)(.79) = 600 BI 203 Human Anatomy & Physiology II Coefficient for O 2 in water is CO 2 in water is 0.57

Take 5!!! Discuss with your neighbor and predict an answer What is the effect on a person’s blood N 2 levels, when diving at depths that are too deep (high pressure) for too long of a time? BI 203 Human Anatomy & Physiology II

How does SCUBA affect the respiratory system? Other anatomy & physiology concerns… Breathing compressed O2 Breathing compressed air while snorkeling Holding your breath longer while snorkeling Nitrogen narcosis Vertigo Not following the rules