The Respiratory System Chapter 11 The Respiratory System

Learning Goal To learn more about the function of the respiratory system and gas exchange To take a closer look at the human respiratory system

Introduction Most of the cells in our bodies need a continual supply of Oxygen (O2) to carry out cellular respiration This process releases energy from glucose inside cells and produces Carbon Dioxide (CO2) as a waste product The left over chemical energy is used for the cell to carry out activities (cellular respiration – Gr. 12)

Introduction – Terms Respiratory System – is the group of organs that provide living things with oxygen from outside the body and disposes of waste products like CO2 Respiration – all the processes involved in bringing O2 into the body, making it available to each cell, and eliminating CO2 as waste

Respiration & Gas Exchange There are Four Stages in human respiration, where each stage has specialized structures to help it: Breathing External Respiration Internal Respiration Cellular Respiration

Respiration & Gas Exchange Stage 1 – Breathing Involves Inhalation (breathing in) and Expiration (breathing out) Inhalation – moves air from outside the body into the lungs inside the body Expiration – moves air from the lungs back to the outside of the body

Respiration & Gas Exchange The inhaled air that enters the alveoli have a greater [ ] of O2 than CO2 The blood that circulates in the capillaries surrounding the alveoli has a greater [ ] of CO2 than O2 The differences in these concentration make a Concentration Gradient that helps gas exchange happen (step 2)

Respiration & Gas Exchange

Respiration & Gas Exchange Step 2 – External Respiration Here, CO2 and O2 is exchanged between the inside of the lungs and the blood This stage is VERY IMPORTANT to our existence via the Gas Exchange Process Is the Delivery of O2 from the lungs to the blood Is the Elimination of CO2 from the blood to the lungs

Respiration & Gas Exchange In the lungs, oxygen diffuses from air in the alveoli into blood in the capillaries At the same time, carbon dioxide diffuses from the blood into the air in the alveoli The carbon dioxide leaves the lungs and exits through your mouth as you breathe out

Respiration & Gas Exchange

Respiration & Gas Exchange Step 3 – Internal Respiration Is the exchange of O2 and CO2 between the blood and the body’s tissues

Respiration & Gas Exchange Stage #4 – Cellular Respiration Is a series of energy-releasing chemical reactions that takes place within cells Go into more detail in Gr. 12 Biology!

Respiratory Surfaces There are 2 main requirements for respiration The Respiratory Surface (place of the body where gas exchange happens) must be Large Enough for O2 and CO2 to exchange fast enough to meet the needs of the body Respiration must take place in a MOIST Environment, so that the O2 & CO2 can dissolve in water

Respiratory Surfaces Instead of Lungs, some animals exchange gases through their outer body surface, gills, or trachea To improve the efficiency of respiration, all organisms use VENTILATION Process of moving an O2 containing medium (water or air) over the respiratory surface (lungs, gills, or trachea)

Gas Exchange in Water Aquatic environments contain Oxygen in a “dissolved gas” form Many aquatic organisms, like Fish, take in O2 through gills Gills help these organisms carry out gas exchange even in water

Gas Exchange in Water Fish exchange gas by Taking water into its mouth and ventilating (pumping) it over the gills As water flows across their gills, dissolved O2 in the water diffuses into the blood At the same time, CO2 diffuses from the blood, across the gill tissue, into the water CO2 is then carried out of the fish’s body when water passes out of the gill openings

Gas Exchange in Water

Gas Exchange with Water

Gas Exchange on Land Air-breathing vertebrates like Mammals, birds, and reptiles rely on their lungs for gas exchange Movements involved in breathing utilize the structure of the lungs and their cavity to aid gas exchange to its fullest potential

The Mechanics of Breathing RECALL: Inhalation causes air to move into the lungs Exhalation causes air to move out from the lungs

The Mechanics of Breathing When you Inhale The muscular diaphragm and the intercostal muscles of the rib cage contract The diaphragm has a dome shape ᴖ when its relaxed INHALING causes the diaphragm to LOWER and FLATTEN At the same time the rib intercostal muscles contract = RIB CAGE MIVES UP AND OUT These contractions allow the lungs to expand, which increases their volume When lung volume ↑ air pressure inside the alveoli ↓ This pressure difference between the lungs and alveoli allows air to flow into the nasal cavity, through the respiratory tract and into the alveoli for gas exchange Respiratory Tract - http://www2.sunysuffolk.edu/pickenc/Respiratory%20System%20Overview.swf

The Mechanics of Breathing When you Exhale The diaphragm and intercostal muscles of the rib cage RELAX The diaphragm moves up and rests normally in the chest cavity The rib cage moves downward and inward These relaxations allow the volume of the lungs to ↓ Air pressure in the lungs is GREATER than air pressure outside the body Hence, air flows naturally from the lungs to outside of the body

The Mechanics of Breathing VIDEOES http://www2.sunysuffolk.edu/pickenc/Respiratory%20System%20Overview.swf http://highered.mheducation.com/sites/0072507470/student_view0/chapter23/animation__gas_exchange_during_respiration.html http://highered.mheducation.com/sites/0072507470/student_view0/chapter23/animation__movement_of_oxygen_and_carbon_dioxide.html

The Spirograph A Spirograph – represents the amount (volume) and speed (rate of flow) of air that moves into and out of the lungs with each breath Video: https://www.youtube.com/watch?v=hQzNG89pESQ

The Spirograph - Key Terms Definition Tidal Volume The volume of air that is inhaled and exhaled in a normal breathing movement when the body is at REST Inspiratory Reserve Volume The ADDITIONAL volume of air that can be taken into the lungs beyond regular / tidal inhalation Expiratory Reserve Volume The ADDITIONAL volume of air tat can be forced out of the lungs beyond regular / tidal inhalation Vital Capacity (Total Lung Volume Capacity) The Total Volume of gas that can be moved into / out of the lungs: Calculated by: = Tidal Vol + Inspir. Res. Vol + Expir. Res. Vol Residual Volume The Volume of air that remains in the lungs AFTER a complete exhalation of the system

Section 11.2 Taking a Closer Look at the Respiratory System

Introduction The structure of the respiratory system can be divided into2 main groups: The Upper Respiratory Tract The Lower Respiratory Tract

The Upper Respiratory Tract Air enters through the nose and mouth into the nasal cavity The NASAL CAVITY is lines with nose hairs and mucus to catch dust, bacteria, and other particles that were inhales with the air but are bad for the body

The Upper Respiratory Tract Air then travels into the PHARYNX (throat) Both inhaled air and food pass through the pharynx from the nasal and oral cavity From here air passes into the LARYNX (vocal cords)

The Upper Respiratory Tract A muscular tissue called the epiglottis works like a swing door opening on purpose for air to enter into the larynx and keeping food out, and vice versa, from food entering the esophagus and not into the larynx

The Upper Respiratory Tract From the larynx air flows into a tube called the TRACHEA (windpipe) The trachea is lined with cilia hairs and mucus to trap pollutants and other particles that made it past the nasal cavity when breathed in

The Lower Respiratory Tract Includes the lungs, bronchi, bronchioles, and alveoli Air continues to flow from the trachea down towards the lungs Inside the lungs are two branching tubes called BRONCHI

The Lower Respiratory Tract These bronchi then also are broken down into a smaller branching network of smaller tubes called BRONCHIOLES Each lobe has its own portion of the network of bronchioles This is beneficial in case one lobe gets injured – the other can still function and supply air to the tissues of the lungs

The Lower Respiratory Tract The smallest bronchioles end at a cluster of tiny air pockets called ALVEOIL Here O2 from inhaled air enters the alveoli and diffuses into the capillaries around them at the same time CO2 in the blood diffuses into the air in the alveoli

The Lower Respiratory Tract

Understanding Gas Exchange During External Respiration (Stage #2), the thin walls of the alveoli and the capillaries allow gases to diffuse through their cell membrane easily

Understanding Gas Exchange

Understanding Gas Exchange As you can see, the air that enters the alveoli AFTER inhalation has a higher [ ] of O2 than the blood in the capillaries next to the lungs

Understanding Gas Exchange Thus, oxygen diffuses out of the alveoli into the blood in the capillaries The blood in the capillaries has a HIGHER [ ] of CO2 than the air in the alveoli This is because CO2 is a waste produce of cellular respiration (step #4) and is brought up to the lungs from other cells in the body to be exhaled out

Understanding Gas Exchange Therefore, the body gets rid of CO2 (waste product) by having it diffuse out from the capillaries and into the alveoli The CO2 is then exhaled out into the air and out of the body as NEW and FRESH O2 is breathed in and the cycle continues

Understanding Gas Exchange The reason why CO2 is able to move out of the capillaries and into the alveoli to be exhaled out And the reason why O2 is able to move from the alveoli and into the capillaries with fresh O2 for cells Is because of DIFFUSION – The movement of a substance from a High [ ] to a Low [ ]

Understanding Gas Exchange Where: There is a high [ ] of CO2 in capillaries and moves to the low [ ] area of the alveoli There is a high [ ] of O2 in the Alveoli from being breathed in and moves to the low [ ] of the capillaries in the blood

Understanding Gas Exchange

How do these gases move around in the body? During respiration, both oxygen (O2) and carbon dioxide (CO2) are transported via the bloodstream 99% of O2 that reaches cells is carried by Hemoglobin (Hb) Is a protein in RBC that is attracted to O2

How do these gases move around in the body? When CO2 leaves tissue cells and diffuses into the capillaries, it enters the RBC 23% of CO2 is carried in the blood by Hemoglobin The other 77% is in the blood as a dissolved gas When CO2 reaches the lungs, it diffuses into the air in the alveoli and is exhaled

How do these gases move around in the body?