The Respiratory System (5) Flashcards
Label the diagram of the respiratory system
In booklet or on flashcard Left side - trachea - rib - intercostal muscles - heart - pleural fluid
Bottom
- Lungs
- diaphragm
Right side
- bronchus
- bronchiole
- alveolus (air sac)
- pleural membranes
Explain the respiratory system
The lungs are in the upper part of the body (the thorax) and are separated from the lower part of the body by a sheet of muscle called the diaphragm. The ribcage provides protection for the lungs. In between each rib are intercostal muscles; these play a role in helping the ribcage to move during breathing.
The plural membrane is a two layered membrane which lines the inside of the chest wall (ribs) and the outside of the lungs. The space between the plural membrane (the pleural cavity) contains a small amount of plural fluid, which reduces the friction between the lungs and the chest walls during breathing.
Air is drawn in through the mouth and nose (nasal cavity) where it is warmed and moistened. It then passes into a pipe called the trachea, which branches into two bronchi (singular: bronchus). The trachea and bronchi contain incomplete (c-shaped) rings of cartilage in their walls. These tough rings of cartilage provide support and keep the trachea and bronchi open I.e. Stop them collapsing during breathing. Bronchi are further divided into smaller tubes called bronchioles lining the trachea, bronchi and bronchioles are many tiny hairs called cilia. Dust particles and microorganisms that are present in the air we breathe get stuck in the sticky mucus that is present in the trachea, bronchi and bronchioles. The cilia move and waft the mucus up to the back of the throat so that it does not enter the lungs. Instead it is swallowed and enters the stomach where it is destroyed.
The bronchioles end in tiny air sacs called alveoli (singular: alveolus), which are surrounded by many capillaries. This is where oxygen moves from the alveoli into the blood to be transported to every living cell to be used for respiration. Carbon dioxide (produced by cells in respiration) will move in the opposite direction - from the blood into the alveoli to be removed from the lungs. The exchange of oxygen and carbon dioxide which takes place between the alveoli and the blood is known as gas exchange.
Give the function for each of these:
- rib cage
- intercostal muscles
- pleural membrane
- pleural fluid
- nasal cavity
- trachea
- bronchi
- rings of cartilage
- bronchioles
- alveoli
ribcage - provides protection for the lungs
intercostal muscles - help ribcage to move during breathing
Pleural membrane - lines inside of chest wall and outside of lungs
Pleural fluid - reduces friction between lungs & chest walls during breathing
Nasal cavity - air is warmed and moistened
Trachea - pathway to lungs lined with c-shaped cartilage
Bronchi - branches to trachea
Rings of cartilage - provide support & keep trachea & bronci open
Bronchioles - smaller branches of bronchi
Alveoli - for gas exchange (air sacs)
Draw a flow diagram to show the path that air follows when it enters the nose until it reaches the alveoli
Nose - trachea - bronchi - bronchioles - alveoli
The nasal passage is lined with small hairs. Why do you think it is better to breathe through your nose than your mouth?
Hairs in nose catch dust and microbes from the air and stops it reaching the lungs
What is gas exchange?
Gas exchange refers to the exchange of oxygen and carbon dioxide which takes place between the air in the alveoli and the blood capillaries in the lungs
What is the function of the respiratory system
To provide body tissues with oxygen and remove carbon dioxide to facilitate the process of respiration
What does gas exchange refer to?
The exchange of oxygen and carbon dioxide which takes place between the air in the alveoli and the blood capillaries in the lungs.
Describe the air in alveoli
Rich in oxygen
Describe the passage of oxygen from inside the alveoli to inside the blood capillary
- dissolved in the film of moisture lining the inside of the alveoli
- diffuses through the walls of the alveoli
- diffuses through the capillary walls into the blood (where the concentration of oxygen is low)
- enters the red blood cells and combines with haemoglobin to form oxyhaemoglobin I.e. the blood is now oxygenated
- carried around the body and is delivered to respiring cells I.e. the blood is now deoxygenated
Describe the movement of carbon dioxide.
Carbon dioxide is carried in the plasma part of the blood. When it reaches the lungs it diffuses from the capillary into the alveoli (in the opposite direction to oxygen) and is then breathed out.
What are respiratory surfaces and what happens here?
The respiratory surfaces are the parts of the body where gas exchange takes place between the atmosphere and the blood. In humans gas exchange takes place in the alveoli i.e. oxygen diffuses into the blood and carbon dioxide into the alveoli
Describe the adaptions of respiratory surfaces, i.e. large surface area
Large surface area - there are many alveoli present in the lungs and each alveolus has a large surface area. This gives a gas exchange surface area of about 70msq i.e. a large area of alveolar walls are in contact with blood capillaries.
They are thin - Alveoli and the blood capillaries have very thin walls (only one cell thick). This means that there is only a short diffusion distance for oxygen and carbon dioxide to travel.
Moist - the walls of the alveoli are moist (film of moisture). the gases dissolve in the moisture, which helps them to pass through the alveoli and into the blood capillary.
Permeable - the moist, thin walls of the alveoli make them permeable for gases to pass through.
Good blood supply - Alveoli are surrounded by capillaries, these carry oxygenated blood away from the lungs and bringing blood with high concentration of carbon dioxide back to the lungs. This helps to maintain the diffusion gradient of the two gases.
Diffusion gradient - Breathing ensures there is a large diffusion gradient present to encourage oxygen to diffuse into the blood and carbon dioxide to diffuse into the alveoli. Breathing in ensures the alveoli contain air with a higher concentration of oxygen than that in the capillary and therefore oxygen diffuses into the blood. Breathing out ensures that the alveoli contain air with a lower concentration of carbon dioxide than that in the capillary and therefore carbon dioxide diffuses into the alveoli.
Explain respiratory surfaces in plants?
The main respiratory surfaces in plants are the spongy mesophyll cells surrounding the air spaces in the leaves.Since there are a lot of cells in contact with the air spaces there is a large surface area and the cell membranes (where gas exchange takes place) are thin, moist and permeable.
What is ventilation?
The movement of the ribs and lungs during breathing is called ventilation. Air is drawn into the lungs using two sets of muscles. These muscles are the diaphragm and the intercostal muscles.
Explain inspiration/inhalation.
When we breathe in:
- the diaphragm contracts and moves down (flattens).
- the intercostal muscles contract causing the ribs to move up and out.
- the volume of the thorax (chest cavity) increases.
- the pressure inside the thorax decreases.
- atmospheric air pressure is higher outside the lungs than inside so air moves in.
Explain expiration/exhalation.
When we breathe out;
- the diaphragm relaxes and moves up (dome shape)
- the intercostal muscles relax, causing the ribs to move down and in
- the volume of the thorax decreases
- the pressure inside the thorax increases
- air is higher inside the lungs than outside it so air is forced out.
-
Summary of breathing.
Inhalation intercostal muscles - contract ribs - moves up and out diaphragm - contacts and flattens volume of lungs - increases pressure in lungs - decreases movement of air - air moves in (lungs inflate)
Exhalation
intercostal muscles - relax
ribs - moves down and in
diaphragm - dome shaped, relaxes and moves up
volume of lungs - decreases
pressure in lungs - increases
movement of air - air moves up (lungs inflate)
