Respiration
Describe what happens during ventilation--inspiration
- external intercostal muscles contract, internal intercostal muscles relax-->the ribs are pulled upwards and outwards -the diaphragm contracts and moves down (flattens) -volume of the thorax increases, so there is less pressure inside -atmospheric pressure is greater so air is drawn in
Changes in blood glucose concentration during exercise
-blood glucose conc. increases OR stays the same -more glucose is available for respiration -to release energy for muscles to contract/work
What happens during expiration
-external intercostal muscles relax, internal intercostal muscles contract, lowering the ribs downwards and inwards -diaphragm relaxes and bulges up due to pressure from organs below and due to contraction of abdominal muscles - as a result of these actions, volume inside the thorax decreases, pressure increases relative to atmospheric pressure-->air is forced out of the lungs
The uses of energy in the body
-muscle contraction -cell division (and therefore, growth, repair and replacement) -maintaining a constant body temperature (some energy is in the form of heat) -protein synthesis for making enzymes, some hormones and antibodies -absorption of nutrients in the gut by active transport -passage of nerve impulses as a means of transferring information along the body -manufacturing new cell membrane and other cell structures like the nucleus during growth
Label the gas exchange system
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List the features of gas exchange surfaces
1. Large surface area for diffusion of gases 2. Moist surfaces so that gases can dissolve before diffusion 3. Thin walls so that gases have a short diffusion distance 4. Good blood supply/supply of oxygen 5. Close to an efficient transport system to take gases to and from the exchange surfaces
Features of the alveoli
1. Very thin--one cell thick to allow rapid diffusion 2. Excellent transport system--blood is constantly pumped to the lungs from the pulmonary artery 3. The transport system branches into a network of thousands of capillaries which take blood to all parts of the lungs 4. They are moist so gases can dissolve before diffusing 5. Large surface area for diffusion of gases
Balanced symbol equation for aerobic respiration
6O2+C6H12O6----->6CO2+6H2O
Distinguish between aerobic respiration and anaerobic respiration
Aerobic uses oxygen, Anaerobic doesn't In aerobic, no alcohol or lactic acid is produced, in anaerobic--lactic acid is produced in human cells, alcohol is produced in microorganisms like yeast. Aerobic produces large amounts of energy, much less energy released from anaerobic respiration In Aerobic respiration, co2 is produced but in anaerobic, co2 is only produced in microorganisms like yeast.
How is the rate of breathing controlled and regulated?
As muscles respire more during exercise, more carbon dioxide (or lactic acid during anaerobic respiration) is produced. This lowers the pH of tissues and the blood, making them more acidic. The hypothalamus detects this change in pH of the blood passing through it, sending nerve impulses to the intercostal muscles and diaphragm to contract faster, increasing the volume of the lungs, thereby increasing rate and depth of breathing.
Explain the link between physical activity and rate and depth of breathing
As the rate of physical activity increases, the rate and depth of breathing increases. This is because, as muscles are working hard (contracting), the rate of their respiration increases, producing larger amounts of CO2 which need to be removed. To maintain this rate, they need a larger supply of oxygen for respiration. As rate and depth of breathing increases, oxygen is delivered to muscles more quickly and carbon dioxide is removed from muscles more quickly.
Outline the role of yeast in brewing
Barley grains provide a source of sugar. During malting, barley seeds germinate. During this time, enzymes in the seeds break down starch in the cotyledon into maltose. The resulting sugar is dissolved in water to make WORT. Mashing: yeast is added to the wort. It respires anaerobically to make alcohol and carbon dioxide. The carbon dioxide give the beer its fizz.
Why does anaerobic respiration release less energy than aerobic respiration?
Because the glucose is not broken down completely and a lot of energy remains stored in lactic acid and alcohol in the form of chemical bond energy.
Symbol equation for anaerobic respiration in human cells during hard exercise
C6H12O6----->2C3H6O3 (+energy)
Symbol equation for anaerobic respiration in yeast
C6H12O6---->2C2H5OH+2CO2
Role of mucus and cilia in protecting the gas exchange system from pathogens and particles
Ciliated epithelial cells and goblet cells line air passages like the trachea, bronchi and bronchioles. Goblet cells produce mucus that traps dust and pathogens. Cilia sweep this mucus up to the nose and throat which is then swallowed after dust and pathogens are removed
Explain the effect of exercise on breathing
During exercise, muscles require more oxygen for aerobic respiration to release more energy as they are contracting much faster, and CO2 also needs to be removed faster. The rate and depth of breathing increase. These changes in breathing are a part of homeostasis-they regulate: -blood pH -oxygen conc. in the blood -co2 conc. in the blood -prevents anaerobic respiration -PREVENTS oxygen debt
Describe the effect of lactic acid in muscles during exercise
During vigorous exercise, the heart rate and depth of breathing increases to supply muscles with more oxygen. However, they cannot do this fast enough, and so more energy is needed. Thus, we respire anaerobically. During exercise, lactic acid builds up in our muscles and even after exercise, it remains in abundance in our body. Lactic acid can slowly poison your muscles and cause cramp, so it needs to be removed from the body. In order for it to break down, it must combine with oxygen in the liver. Thus, after exercise, we continue to breathe in deeply; this extra oxygen is used to break down lactic acid in the liver, thereby repaying the oxygen debt that we have created when we respire anaerobically. Even the heart rate remains high after exercise to deliver lots of blood to the muscles to remove the lactic acid that has been built up.
Word equation for aerobic respiration
Glucose+oxygen---->carbon dioxide+water (+energy)
Word equation for anaerobic respiration in human cells during hard exercise
Glucose---->lactic acid (+energy)
Word equation for anaerobic respiration in the microorganism-yeast
Glucose--->carbon dioxide+alcohol (+energy released)
Equation for calculating energy content of food
Heat energy (J)=temperature change (degrees Celsius) *volume of water (cm^3)*4.2
Outline the role of yeast in breadmaking
In bread dough, there is a mixture of sugar, flour water, salt etc. Yeast is added to the dough and it breaks down the sugar as it respires, producing alcohol and carbon dioxide. The CO2 makes the bread rise. There is no alcohol present in the bread because it evaporates due to the heat of the oven.
Where are the lungs found
Inside the thorax, protected by ribs and sternum
Passage of air through the gas exchange system
Inspired air enters he larynx, which also contains the vocal cords. Then it passes through the trachea, bronchi and bronchioles, eventually to enter the alveoli where gas exchange takes place.
What are pleural membranes?
Membranes that surround the lungs and contain fluid in between them, which prevents the lungs from rubbing against each other
State the differences in composition between inspired and expired air
Oxygen: 21% inspired air, 16% expired air-->oxygen absorbed across gas exchange surface into blood capillary and used by cells in respiration Carbon dioxide: 0.04% inspired air, 4% expired air-->carbon dioxide released as a bi product during respiration Argon and other noble gases: always 1% Water content: variable in inspired air, always high in expired air--> gas exchange surfaces are made of living cells, so must be kept moist; some of this moisture evaporates into the air. Also, water is released during aerobic respiration. Temperature: variable in inspired air, always high in expired air-->some energy released from respiration is in the form of heat; also, air is warmed as it passes through the respiratory passages
Changes in pulse rate during exercise
Pulse rate increases Blood is transported faster to muscles Because muscles require more oxygen And require CO2 and lactic acid (As well as heat) to be removed faster
What is the diaphragm
Sheet of fibrous tissue and muscle separating the thorax and the abdomen
What are bronchioles?
Subdivisions of bronchi, ending in alveoli
What are alveoli?
The alveolus is a tiny air sac in the lungs where exchange of gases between the air and the blood occurs.
Define respiration
The chemical reactions that break down nutrient molecules in living cells to release energy
What is the epiglottis?
The flap in the throat which prevents food going inside the trachea
Define aerobic respiration
The release of a relatively large amount of energy in cells by the breakdown of glucose in the presence of oxygen
Define anaerobic respiration
The release of a relatively small amount of energy in cells by the breakdown of glucose in the absence of oxygen
What are intercostal muscles?
They are located between the ribs and move the ribs during breathing
What are bronchi?
Two structures branching off from the trachea, entering each lung.
What is the larynx
Voice box--sound is produced when air passes above it, making it vibrate
Describe what happens during gas exchange at the alveolus
When inspired air enters the alveolus in the lungs, oxygen diffuses out of the alveloli into the blood capillary (into the red blood cells) and combine with haeomoglobin; the capillary leads to the pulmonary vein which connects to the heart which leads onto parts in the rest of the body. Carbon dioxide released from previous respiration diffuses out of the plasma in the capillary into the alveolus. From here, it is breathed out.
What is fermentation?
When microorganisms respire anaerobically, it is called fermentation.
What is the trachea
Wind pipe. It connects the throat to the lungs.
