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The Mechanism of Breathing

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Presentation on theme: "The Mechanism of Breathing"— Presentation transcript:


2 The Mechanism of Breathing
(Anatomy of Breathing Flash Animation)


4 Inhalation The Intercostal muscles contract, sending the rib cage upward and outward The Diaphragm contracts, and moves downward The Volume inside of the chest cavity increases The Pressure inside the chest cavity decreases Air enters the lungs to equalize the pressure

5 Exhalation The Intercostal muscles relax, sending the rib cage downward and inward The Diaphragm relaxes, and moves upward The Volume inside of the chest cavity decreases The Pressure inside the chest cavity increases Air exits the lungs to equalize the pressure

6 Another Animation

7 Carbon Dioxide Concentration Nitrogen Concentration
Inhaled vs. Exhaled Air Inhaled Air Exhaled Air Oxygen Concentration 21 % 16 % Carbon Dioxide Concentration 0.04 % 5 % Nitrogen Concentration 78 % Dryness Drier Moist Temperature Colder or Warmer than 37 C Warm (close to 37 C) Cleanliness Dirtier *Cleaner (filtered) *Exhaled air may contain bacteria or viruses, but is cleaner in terms of dust or pollutants

8 Turbinate Bones Increase Surface Area and Increase the rate of
Filtering Warming and Moistening of air

9 Breathing versus Respiration

10 Breathing: The act of bringing air in and out of lungs; consists of inhalation and exhalation; it is an external mechanical process Cellular (Cell) Respiration: When glucose (food) and oxygen combine to produce carbon dioxide, water and ATP energy; occurs in the mitochondria of cells; it is an internal chemical process Equation: C6H12O6 + O CO2 + H2O + ATP

11 How are Breathing and Cell Respiration Connected?
In order for cell respiration to occur, oxygen must move into cells, while carbon dioxide must move out of cells. The exchange is made in the lungs during breathing

12 Exchanges made between the lungs and the blood are said to be external exchanges, because the lungs are open to the outside of the body.


14 Gas Exchange

15 Carbon dioxide and oxygen swap places.
The gases move by a process called diffusion. In animals, oxygen is moved from the air in the lungs to the blood, and then from the blood to the cells. Carbon dioxide moves in the opposite direction Lungs O2 Blood Cells CO2

16 http://www. youtube. com/watch

17 Label and Color the Alveolus Diagram
Use Red for oxygenated blood and Blue for deoxygenated blood

18 Conditions required for Gas Exchange
Thin walls (air sacs and blood vessels) – so that gases can pass through the walls Moist walls – so that gases can dissolve and pass into the blood and cytoplasm of cells (which need materials in liquid, not gaseous form)

19 3. Concentration gradient – so that gases can move by diffusion; movement of molecules occurs from higher towards lower concentrations 4. Pressure gradient – so that the gases can be pushed in the direction that they need to move into; molecules will move from areas of higher towards areas of lower pressure High Low

20 Effect of Altitude on Gas Exchange
At Sea Level, Air Pressure is Higher because there are more air particles on top of you

21 At high altitudes (like up on a mountain):
There are lots of oxygen molecules But oxygen molecules can’t get into the body cells This is because: There isn’t enough pressure To push the oxygen from the lungs across the air sacs, blood vessels, and cell membranes into the cells where the oxygen is needed.

22 At HIGH altitudes…. Pressure Gradient Diffusion Gradient
The Diffusion Gradient is in the right direction but the Pressure Gradient is not

23 Gas Transport Oxygen and Carbon dioxide are carried in the blood stream. Oxygen is carried from the lungs to cells which then use the oxygen for cell respiration. Carbon dioxide is produced by cell respiration and is carried from the cells to the lungs to be exhaled.

24 Hemoglobin A chemical found inside red blood cells.
It has 4 binding spots for gas molecules. There are many hemoglobin molecules in each red blood cell. Hemoglobin can carry oxygen carbon dioxide hydrogen ions carbon monoxide

25 A hemoglobin molecule consists of 4 Globular proteins (polypeptide chains) bound to a central iron (Fe) atom (called a Heme group)….hence the name Hemo Globin. Blood Vessel Fe Red blood cell

26 Oxygen Transport Oxygen travels through the blood stream in 2 ways:
Dissolved in the blood plasma (3%) Attached to hemoglobin – oxyhemoglobin (97%) (Hb O HbO2) Diagram: (3 min. Pre-load to avoid ad, stop showing at graph) Blood vessel 97% RBC 3% in plasma

27 Carbon Dioxide Transport
Carbon dioxide travels through the blood stream in 3 ways: Dissolved in the blood plasma (9%) Attached to hemoglobin – carbaminohemoglobin (27%) (Hb CO HbCO2) As a combination of bicarbonate ions dissolved in blood plasma and hydrogen ions attached to hemoglobin - acid hemoglobin (64%) (Hb H HHb) Diagram: Blood Vessel 27% CO2 9% CO2 and 64% HCO3- in plasma 64% H+

28 If carbonic acid were allow to accumulate in the blood vessels, it would cause respiratory acidosis and could damage blood vessel walls The body solves this problem by buffering the blood Once hydrogen ions are generated they are “hidden away” inside red blood cells – they attach to hemoglobin to become “acid hemoglobin” The bicarbonate ions are benign and can travel through the blood vessels without causing problems

29 Carbon Monoxide Transport
Carbon monoxide (CO) binds to hemoglobin 200X more tightly than oxygen Even if there is plenty of oxygen present, the hemoglobin will choose CO over oxygen, leading to the death of the person. Carbon monoxide is a colorless and odorless gas that is a by-product of combustion reactions – found in smoke. It is very important to have a carbon monoxide detector in your home.

30 Control of Breathing Number of breaths per minute taken at rest is about 14-20 More when exercising Breathing rate and heart rate are tied together Breather rate and depth control by the medulla oblongata and the pons in the brain

31 Nervous Control of Breathing
Sensors called chemoreceptors detect CO2 levels in blood Higher CO2 levels = faster and deeper breathing To speed rate and depth of breathing, the brain sends messages to the diaphragm & intercostal muscles using sympathetic nerves

32 Nervous Control of Breathing
Brain Nervous Control of Breathing Muscles contract faster to speed up rate of breathing when CO2 is high Muscles contract slower to slow rate of breathing when CO2 is low

33 Feedback Loops

34 Exercise Hold breath Certain drugs High CO2 Levels in Blood Chemo- receptors (medulla & Pons) Intercostal muscles Diaphragm Rate of breathing Increases


36 High Altitude Athletic Training
Training in places with higher elevations (ex. Colorado) in order to increase lung capacity and thus performance At first - breathing & heart rates will be higher than normal After a few months of training.... The lungs have stretched Breathing rates return to normal breaths/minute More capillaries grew around alveoli to accommodate a faster gas exchange More red blood cells will have been added to the blood stream for a greater oxygen carrying capacity. The athlete then returns to lower altitudes to compete

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