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Flashcards in The Respiratory system Deck (11):

What's the role of diffusion in gas exchange?

In the circulatory system O2 enters the blood and CO2 leaves the blood by gas exchange. Gases move across the walls of the alveoli to an area of lower density than they are in.

-O2 move to blood as there is a low density of O2 in blood


Function of the respiratory system

Gas exchange:
-uptake of O2
-release of CO2


How are the lungs adapted for efficient gas exchange?

1. SA
-alveoli have folded shape (large SA/V ratio)
-high numbers of alveoli

2. Concentration gradient
-allows diffusion to occur

3. Diffusion distance
-short distance so fast diffusion
-alveoli wall 1 cell thick
-capillary wall 1 cell thick


Label lungs diagram

do it


The effects of smoking on the respiratory system

-Tar builds up in lungs and can cause cancer
-Constricts arteries and putting a strain on the heart, resulting in coronary heart disease
-Cilia paralysed, mucus builds up, debris in lung not removed
-Carbon monoxide binds irreversibly to haemoglobin, reducing oxygen supply

-Decreased fertility, lower birth mass

-Nicotine is addictive


Gas exchange in the alveoli

-Air in and out from terminal bronchiole
-Blood from pulmonary artery, to pulmonary vein
-CO2 from blood, O2 to blood


What happens during inhalation?

diaphragm muscles: contract (flattens, at bottom)
external intercostal muscles: contract
rib cage: pulled up and out
volume of chest cavity: increases
lungs: expand
pressure in lungs: lower than outside body
air: rushes into lungs to equalise pressure


What happens during exhalation?

diaphragm muscles: relax (dome shaped)
internal intercostal muscles: contract
rib cage: pulled down and in
volume of chest cavity: decreases
lungs: volume decreases
pressure: higher than outside body
air: moves out


Tidal volume

volume of air breathed in and out in a single breath


respiratory key words:

found on quizlet


Composition of Air

Breath in: