7 — respiration in humans Flashcards
Respiration
- the breaking down of food molecules such as glucose to release energy.
- Glucose + 6O2 -> 6CO2 + 6H2O + energy (converted to heat)
Aerobic respiration
Is the release of large amount of energy by the oxidation of glucose in the presence of oxygen. Carbon dioxide and water are released as waste products.
Glucose + Oxygen -> carbon dioxide + water + large amount of energy
C6H12O6 + 6O2 -> 6CO2 +. 6H2O + large amount of energy
Anaerobic respiration
Is the release of energy by the oxidation of glucose in absence of oxygen. Anaerobic respiration releases relatively lesser amount of energy as compared to aerobic respiration and releases lactic acid as waste product.
Glucose -> lactic acid + small amount of energy
Test for aerobic respiration
Test CO2 as one of by products:
- Hydrogencarbonate indicator setup
- Limewater
Test for anaerobic respiration
CO2 given off during fermentation in yeast:
- Glucose solution boiled n cooled to remove dissolved O2 from solution
- Limited O2 available to yeast -> anaerobic respiration occurs
- Limewater will form white precipitate in presence of CO2 from anaerobic respiration of yeast
Process of respiration
- Exercise – Increases muscle contractions →energy requirement increases
- Heartbeat rate and breathing ^ to increase blood supply rich in O2 and glucose to muscles + ^gaseous exchange to obtain ^ oxygen, remove CO2 faster
- Continuous muscle contractions occur
- Energy from maximum rate of aerobic respiration is insufficient to supply increased demand, oxygen deficit occurs
- Anaerobic respiration occurs to meet high energy demand
- Production of lactic acid -> oxygen debt + definition (Glucose -> lactic acid) →Accumulation
- High heart n breathing rate continues to repay oxygen debt n remove lactic acid from muscles
- Lactic acid transported to liver is oxidised to release energy to convert remaining lactic acid to glucose
- Transported back to liver to store as glycogen
- Fatigue, muscular pains, cramps occurs
Oxygen debt
the volume of oxygen required to break down the lactic acid produced in muscles during anaerobic respiration
Oxygen deficit
The difference between the oxygen the body needs during the activity and what it actually managed to take in is called oxygen deficit.
How oxygen debt is paid
- Continued fast heart rate
- to transport lactic acid from muscles to liver via blood for removal
- transport oxygen from lungs to liver
- Continued deeper and faster breathing
- to obtain oxygen for supply to liver for removal of lactic acid to pay oxygen debt
- In the liver, oxygen is used to oxidise some lactic acid to release energy -> used to convert the remaining lactic acid back to glucose to store inside liver as glycogen.
Oxygen debt is paid when lactic acid is removed.
Nose’s adaptations and functions
A fringe of hairs on walls of nostrils
- Dust & foreign particles, including bacteria r trapped by the hairs in the nostrils and the mucus on the mucous membrane.
2 nasal passages lined with a moist mucous membrane
- Air is warmed & moistened
- Harmful chemicals can be detected by small sensory cells in mucous membrane
Trachea
Contains thin epithelium membrane next to lumen
- Epithelium consists of :
Gland/goblet cells -> secrete mucus to trap dust particles & bacteria
Cartilage keeps lumen of trachea open
- Ciliated cells -> hv cilia (hair-like structures) on their surfaces to sweep dust trapped mucus up trachea
Gas exchange in alveoli
- Blood entering lungs hv lower conc of O2, ^CO2 than atmospheric air entering alveoli in lungs -> steep conc gradient for O2 and CO2 betw blood n alveolar air maintained by continuous blood flow thru capillaries & breathing -> faster rate of diffusion of gases
- O2 dissolves into thin film of moisture on alveolar wall
- Dissolved O2 diffuses thru wall of alveolus n wall of blood capillary into RBCs
- O2 combines with haemoglobin to form oxyhaemoglobin
- CO2 diffuses from blood into alveolar air
Inhalation/inspiration
- Diaphragm muscle contracts & flattens.
- External intercostal muscles contract while internal intercostal muscles relax
- Rib cage swings upwards and outwards. Sternum moves up and forward.
- Volume of thoracic cavity increases, lungs expand and air pressure inside decreases.
- Atmospheric pressure is higher than pressure in lungs Thus air is forced into the lungs.
Exhalation/ expiration
- Diaphragm muscle relaxes & arches upwards.
- External intercostal muscles relaxes while internal intercostal muscles contracts
- Ribs swings downwards and inwards. Sternum moves down to original position
- Volume of thoracic cavity decreases, lungs compressed and air pressure inside increases.
- Atmospheric pressure is lower than pressure in lungs -> air is forced out of lungs into exterior env
Lung cancer cause n effects
C: Tobacco smoking ^risk
E: Lumpy tissue due to uncontrolled growth of cells