T15 Gas Exchange in Humans Flashcards
describe order of thorax
trachea, bronchus, bronchioles, alveoli
explain fucntion of the ribs
around lungs to provide protection for internal organs
explain fucntion of the intercostal muscles
muscles between ribs that control inhalation/exhalation
explain fucntion of the diaphragm
muscular dome - bottom of thorax - chanes pressure of lungs to control inhalation/exhalation
explain fucntion of the trachea
windpipe - where air enters thorax and flows to lungs
explain fucntion of the bronchi
trachea divides into 2 bronchi , into each lung
explain fucntion of the bronchioles
bronchi further split into small tubes connected to alveoli
explain fucntion of the alveoli
tiny air sacs - site of gas exchange
explain fucntion of the pleural membranes
found on outside of lungs inside of chest cavity - to lunricate lungs, reducing friction when breathing
how thorax does inhalation
- intercostal muscles contract and ribs go up and out
- diaphragm contracts downwards, creating larger volume of space for air to difffuse in
- air pressure decreases
- air moves in (air moves from area of high pressure to low pressure)
how thorax does exhalation
- intercostal muscles relax and ribs go down and in
- diaphragm relaxes upwards, smaller volume of space for air
- air pressure increases
- air moves out
why do we need to breathe in and out?
in = to get oxygen into blood for respiration through alveoli
out = remove waste products, carbon dioxide
how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries
- folded - large syrface area to increase rates of diffusion
- thin cell wall - one cell thick, short diffusion distance
- large network of capillaries - increases concentration gradient between air in alveoli and blood, oxygen moves away in blood and carbon dioxide breathed out
CONSEQUENCES OF SMOKING
how tar affects air passages
- Tar in cigarettes destroy the Cilia (which carries away dust and microbes trapped in Mucus), therefore causing the buildup of Mucus and increasing risk of Bronchitis
- Tar in cigarettes contain carcinogens that increases risk of Lung Cancer
CONSEQUENCES OF SMOKING
how tar affects alveoli
- Tar in cigarettes break down Alveoli walls and causes them to merge together, decreasing the surface area to volume ratio for gas exchange
- Insufficient gas exchange will increase the risk of Emphysema - shortness of breath due to insufficient Oxygen transport in blood
CONSEQUENCES OF SMOKING
how is emphysema caused?
emphysema=shortness of breath due to little oxygen transport in blood
- caused by smoking and breathing in dust
- due to frequent infection, enzyme released by phagocytes to break down elasticity in alveoli
- alveoli become less elastic and cannot strecth to burst
- brekadown of alveoli reduces surface area for gas exchange
- patients become breathless and wheezy, may need constant supply of oxygen
Carbon Monoxide from cigarette smoking will bind irreversibly to Haemoglobin, reducing capacity of Oxygen transport by Red blood cells and hence increases the risk of Emphysema
CONSEQUENCES OF SMOKING
how is coronary heart disease caused?
- nicotine causes blood vessels to narrow - leads to build of fat globules (higher blood pressure) - damaging artery wall more likely and blood clots to form - fully blocking artery
- creates blockage of coronary arteries - means heart has less supply of oxygen - can die as less aerobic respiration
- may interfere with heart beat - causing heart attack
CONSEQUENCES OF SMOKING
how is chronic bronchitis caused?
- overporduction of mucus to catch tar from smoking, bronchi becomes inflamed and narrowed
- mucus not produced as much
- narrowed bronchus causes -> breathing is harder, damages alveoli further, leads to emphysema
CONSEQUENCES OF SMOKING
how carbon monoxide affects people?
- CO joins with haemoglobin in red blood cells in place of oxygen - less oxygen transported in blood
- leads to low birth weight of mother - baby won’t have enough oxygen - won’t have oxygen for respiration to produce glucose for energy for growth
practical: investigate breathing in humans, including the release of carbon dioxide and the effect of exercise
- Measure and record the breathing rate (number of breaths per minute - 10 seconds x 6 - more accurate - less anomalies) of the participant at
rest. - Carry out a specific exercise (eg. running/jumping) for a fixed period of time eg.1 minute.
- Measure the breathing rate of the participant again.
Explain why after exercise, the breathing rate increases
- breathing rate increases to get more oxygen in blood
- more oxygen to muscles
- muscles more oxygen for aerobic respiration for more muscle contractions
- more energy released, so more muscle contractions
- less anaerobic respiration - so less lactic acid
