SCIENCE 8 RESPIRATION WHEN WE BREATHE, WHAT DO WE BREATHE IN? O2, N2, CO2, O3, NO2 (gas fumes), CO, pollutant, fragrants, toxins, etc. WHAT IS THE PURPOSE OF BREATHING IN? WHAT DOES OUR BODY WANT? O2 WHY? WHAT DO WE NEED O2 FOR? Let's investigate why we need oxygen... Let's investigate the purpose of cellular respiration. Cellular Respiration: -the reactions that occur within cells. -every cell in the body obtains O2 molecules (remember: there are 2 oxygen atoms in an oxygen molecule; O2 is an element!!!!) -O2 is needed for cells to release the energy stored in glucose molecules. Where do the glucose molecules come from? FOOD! Carbohydrates! What are they for? ENERGY!!! Word Equation for Cellular Respiration: enzymes GLUCOSE + OXYGEN ---------------- energy + CO2 + H2O Can you identify the reactants in this equation? Can you identify the products in this equation? We know where each of the reactants comes from. Let's take a look at the products: ENERGY: moves muscles, transmits nerve impulses, help you do all body processes CO2: -it is a waste product -too much CO2 alters the acidity of the blood -although it is a waste product, it does perform a useful function: it causes the Nervous System to increase or decrease the breathing rate as needed. H2O: -it is a waste product -it is removed by the skin by evaporation. -it is removed by the kidneys by excretion. -it is removed by the lungs by evaporation. (i.e. seeing your breath on cold day). Notice that all waste products MUST be removed!!!!!
#1 - time how long you can hold your breath. athletes and swimmers can hold their breath longer because they have developed their vital capacity or lung capacity. smokers/people with breathing disorders such as asthma will have a harder time holding their breath. #2 - Have your partner count your breathing rate in one minute. What could be wrong with this exercise? When you are thinking about your breathing, you may alter the rate. Breathing is an unconscious activity, and being conscious of it may change how fast or deep you breathe. Would be better if I chose people to secretly count their partner's breathing rate. We now know that the exchange of gases must occur for us to LIVE Exchange of what two gases? O2 and CO2 What a complicated system we have built into our bodies! A series of COMPLEX chemical reactions so that we can breathe, think, move, digest food to get energy. etc.
RESPIRATION and the PARTS OF THE RESPIRATORY SYSTEM Respiration is the transfer of gases between structures. It occurs at two different levels: INTERNAL: the transfer of gases occurs at the level of the cell in complex chemical reactions. EXTERNAL: occurs within a group of organs working together as the "machinery" that exchange CO2 and O2 with the environment. REFER TO THE DIAGRAM(s) OF THE RESPIRATORY SYSTEM AS YOU REVIEW THESE NOTES: NOSE AND NASAL CAVITY -possess structures that filter harmful contaminants from the air. The nose contains a combination of mucous and hair that helps to filter out all sort of solids particles (e.g.. dust and bacteria). (The reason why you sneeze is to remove these filtered contaminants!) The moisture in the nose and nasal cavity helps to humidify the air. Breathing through your mouth is a shortcut. Often when you are breathing "heavy" (e.g. exercise, fright), you will breathe through your mouth in order to get more air in, faster. When you breathe through your mouth you skip the humidifying and filtering steps. PHARYNX Air travels down the pharynx which separates into two passages: the esophagus and the trachea. LARYNX It is at the top of the trachea. It contains the vocal cords. It is made up of cartilage (the largest being the Adam's apple) Air that is released from the lungs goes bast the larynx and vocal cords. TRACHEA The walls of the trachea are made up of rings of cartilage. The walls of the trachea produce mucous which is then swept out of the passageway, into the digestive system. It is the passageway for air to the lungs.
BRONCHI singular: bronchus It branches from the trachea into right and left bronchi. These branches enter the lungs. The bronchi then divide into smaller and smaller passageways called bronchioles. ALVEOLI singular: alveolus These are the subdivisions of the bronchioles. They are clusters of tiny hollow air sacs. These membranes are full of capillaries, so exchanges of gases occurs here (because close to the flow of blood) DIFFUSION OCCURS HERE Recall that diffusion means that chemical compounds move from an area of higher concentration to an area of lower concentration. Therefore, CO2 diffuses from the blood, where it is in high concentration, into the alveoli (so that it can be sent OUT of the lungs) And O2 diffuses from the alveoli, where it is in high concentration, into the blood, where it is in low concentration, so that the blood will receive lots of O2 to distribute to the rest of the body. LUNGS Two firm, spongy organs. They have muscular walls surrounding them. They are completely closed off from the rest of the body by the neck at the top, and a large, dome-shaped sheet of muscle, the DIAPHRAGM, at the bottom. we will discuss the diaphragm later. Can you identify all 7 structures that we just wrote notes on? Where is the larynx? (by the "fork" in the road - in the pharynx) Which are the lungs? Notice the "tree" branches - the BRONCHI
The Respiration Process: A summary: When you breath in, air rushes past your cilia in your nose and is filtered and humidified. OR it goes through your mouth. It then passes into your pharynx, through your larynx and vocal cords, and through your trachea where it passes more cilia and mucous. The air will then travel through either the right or left bronchus and then will branch off into a smaller bronchiole. Once the air reaches the end of a small bronchiole, it arrives at the moist surface of an alveolus. The capillaries surrounding each alveolus allow the exchange or DIFFUSION of gases to occur. Air in the alveoli must be constantly replaces to ensure that oxygen continues to enter the blood and carbon dioxide continues to leave the blood. We breathe in 21 % O2 and 0.04 % CO2 We breathe out 16 % O2 (we only use up about 5 % of the oxygen that we breathe in!) and 5 % CO2 Your nervous system constantly monitors the CO2 levels in your system, causing you to take deeper and faster breaths if your CO2 concentration is high (and your O2 concentration is low). Hence you will breathe out and expel more CO2. When your CO2 concentration decreases, your breathing goes back to normal. REVIEW the PROCESS: When you breathe in: -the muscle called the diaphragm which is at the bottom of the lungs pulls down. -this causes the lungs to expand or become bigger. -the ribs raise up -air enters the lungs volume of lungs INcreases as the pressure in lungs INcreases and the pressure of the chest cavity DEcreases When you breathe out: -the diaphragm muscle relaxes and moves back up towards the lungs -hence the lungs contract or become smaller -the ribs lower -air is forced out of the lungs volume of lungs Decreases as the pressure in lungs Decreases and the pressure of the chest cavity Increases NOTE: chest cavity and lungs always trying to equalize pressure
1. WHAT IS RESIDUAL AIR? RESPIRATION - IMPORTANT and INTERESTING STUFF -the amount of air left behind in your lungs after a normal breath. 2. WHAT IS VITAL CAPACITY? -the largest volume of air that your lungs can move in one breath. 3. NOSE FILTRATION 4. CO GAS 5. HiCCUPS 6. IMPORTANCE OF FE -the molecules in the blood responsible for bonding with the O 2 molecules that you breathe in are called hemoglobin. (it is often said that Hb "absorbs" O 2 ) -Fe bonds with the Hb to make it more efficient at "absorbing" oxygen 7. YAWN -decreased oxygen -or the "social" yawn 8. THE DIFFUSION OF CO2 AND O2 AND WHY IT OCCURS IN LUNGS AND CHEST CAVITY DURING BREATHING 9. PUNCTURED LUNG -hole in lung (it collapses) -pressure in lung can't be controlled -can never fill air in lung -pressure in cc increases -SUFFOCATION 10. CHEST WOUND -hole in chest cavity -pressure increases in cc because air is "sucked" into hole -lung can not expand because too much air in cc