breathing and gas exchange

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  • Created by: sophie_kk
  • Created on: 22-12-19 18:32
breathing
mechanism that moves air into and out of the lungs, allowing gas exchange to take place
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structure of the gas exchange system
lungs enclosed in the chest/thorax by the ribcage and a muscular sheet of tissue called the diaphragm. joining each rib to the next are two sets of muscle called intercostal muscles. the diaphragm separates contents of the thorax from the abdomen
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what are the air passages of the lungs known as?
the bronchial tree
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where does the air go when we breathe in
enters through the nose or mouth, and passes down the trachea. the trachea then splits into two tubes called the bronchi, one leading to each lung. each bronchus divides into smaller and smaller tubes called bronchioles, eventually ending at
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microscopic air sacs, called alveoli (singular alveolus). gas exchange takes place here.
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what do the walls of the trachea and bronchi contain?
rings of cartilage. they support the airways and keep them open when we breathe in. without them, the walls would squash flat when we **** air in
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describe the structure of the thorax
separated from the lungs by two thin, moist membranes called pleural membranes. between the two membranes is a space called the pleural cavity, filled with a thin layer of liquid called the pleural fluid that acts as lubrication, so the surfaces of
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the lungs dont stick to the inside of the chest as we breathe
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what is the effect of the pleural membrane?
forms a continuous envelope around the lungs, forming an airtight seal
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how are the airways kept clean?
goblet cell - in the lining secrete mucus, that traps particles of dirt or bacteria that are breathed in. ciliated epithelial cell - covered in tiny hair like structures that beat back and forth, sweeping the mucus and trapped particles out towards
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the mouth. this way, the dirt and bacteria cannot enter the lungs, where they might cause an infection.
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ventilation
air moving in and out of the lungs - requiring a difference in air pressure
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what takes place during inhalation?
1. ribs move up and outwards( external intercostal muscles contract) 2. at the same time diaphragm contracts - pulling downwards 3. this causes a drop in pressure and an increase in volume of the chest cavity 4. air is sucked into the lungs
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sucked into the lungs
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what takes place during exhalation?
1. external intercostal muscles relax, and internal intercostal muscles contract, pulling the ribs down and in 2. diaphragm relaxes and returns to its domed shape 3. this increases pressure and lowers volume 4. this forces the air out of the lungs
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what Is a quality of the lungs?
they are elastic so they have a tendency to collapse and empty like a balloon.
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percentages of nitrogen, oxygen, carbon dioxide and other gases in atmospheric air
78, 21,0.04,1
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percentages of nitrogen,oxygen, Carbon dioxide and other gas in exhaled air
79, 16,4,1
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what is the difference between exhaled air, and atmospheric air?
exhaled air is warmer, and is saturated with water vapour
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how do the alveoli work?
1. deoxygenated blood is pumped from the heart to the lungs 2. around the lungs, the blood is separated from the air inside each alveolus by only two cell layers - short diffusion path 3. air in alveolus has a high conc of O than the blood entering
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the capillary network - so oxygen diffuses from the air across the wall of the alveolus and into the blood 4. at the same time, there is more CO2 in the blood than there is in air, so CO2 diffuses from the blood across the wall of the alveolus and
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into the alveolus.
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practical: investigate the CO2 content of inhaled and exhaled air
1. a central tube connected to two separate tubes leading to boiling tubes filled with limewater are setup, 2. a person breathes gently in and out through the middle tube 3. exhaled air is passes out through one tube of indicator solution, and
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inhaled air is drawn in through the other tube 4. the limewater will turn cloudy in the 'exhaled' tube, before the 'inhaled' tube , as there is a higher concentration of CO2 in exhaled air
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practical: an investigation into the effect of exercise on breathing rate
1. have a person site quietly for 5 mins 2. count the number of breaths they take in one minute, recording their results in a table 3. they wait a minute and count their breaths again in order to get a steady value for 'resting rate' 3. the person
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then undergoes vigorous exercise, such as running on the spot for 3 minutes 4. immediately after exercise is finished they sit dow and record breathing rate as before 5. they then continue to record their breaths per minute, every minute until they
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return to their normal resting rate
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emphysema
lung disease - smoke from smoking damages the wall of the alveoli, which break down and fuse together again, forming enlarged, irregular air spaces.
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what does emphysema do?
reduces the Surface area for gas exchange, so the blood of a person with this carries less oxygen, and can make it hard to carry out even mild exercise such as walking.
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what does cigarette smoke contain?
contains nicotine, and over 60 chemicals known as carcinogenic - and are contained in the tar that collects on a smokers lungs.
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when does cancer occur?
when cells mutate and divide uncontrollably, forming a tumour
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what does carbon monoxide do?
enters the bloodstream and attaches with the haemoglobin more tightly than oxygen can - when this happens, the blood carries much less oxygen around the body
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what happens if a pregnant woman smokes?
she will be depriving the unborn fetters off oxygen, affecting growth and development, and leads to the mass of the baby at birth being lower
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bronchitis
irritation of the bronchial tree, along with infections from bacteria in the mucus can cause the blockage of normal air flow, so the sufferer has difficulty breathing properly
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what causes bronchitis?
cilia are destroyed by cigarette smoke, and irritates the lining of the airways - stimulating goblet cells to secrete more mucus ; leading to a buildup of 'sticky mucus' blocking the airways
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Other cards in this set

Card 2

Front

structure of the gas exchange system

Back

lungs enclosed in the chest/thorax by the ribcage and a muscular sheet of tissue called the diaphragm. joining each rib to the next are two sets of muscle called intercostal muscles. the diaphragm separates contents of the thorax from the abdomen

Card 3

Front

what are the air passages of the lungs known as?

Back

Preview of the front of card 3

Card 4

Front

where does the air go when we breathe in

Back

Preview of the front of card 4

Card 5

Front

cont

Back

Preview of the front of card 5
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