LC Biology > The Human Breathing System > Flashcards

The Human Breathing System Flashcards

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1
Q

What is the breathing system also known as?

A

The respiratory system.

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2
Q

Where is the breathing system located?

A

In the chest, or thoracic, cavity.

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3
Q

What type of system is the breathing system?

A

It is a type of excretory system composed of many individual organs.

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4
Q

What does the respiratory system function in?

A

Gas exchange.

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5
Q

What is the average human lung capacity?

A

5L.

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6
Q

(14 points)

What is the structure of the breathing system?

A

The breathing system consists of the nasal cavity; buccal cavity (mouth); pharynx; epiglottis; larynx; trachea; rings of cartilage; bronchi; bronchioles; alveoli; diaphragm; pleural membranes; intercostal muscles; and rib cage.

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7
Q

Why does the nasal cavity have a lot of mucous and tiny hairs?

A

To filter the incoming air.

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8
Q

Why are the passages of the nasal cavity moist?

A

To humidify (moisten and warm) the air flowing past. This allows for more efficient gas exchange in the lungs.

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9
Q

How is the air breathed in through the mouth different to the air breathed in by the nose?

A

Air flowing through your buccal cavity is not filtered, warmed or moistened.

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10
Q

What is the pharynx?

A

The pharynx is the throat.

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11
Q

What is the epiglottis and what does it allow?

A

A flap of tissue located at the bottom of the pharynx that closes over the glottis during swallowing. This allows food to pass down the oesophagus.

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12
Q

What is the glottis?

A

The glottis is the opening to the trachea.

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13
Q

What is stimulated when “food goes down the wrong way”?

A

The “gag” reflex that prevents choking.

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14
Q

What is the larynx and what is it responsible for?

A

The voice box. It contains vocal cords and is responsible for producing sounds by modulating (changing the direction and/or speed) the flow of air leaving the lungs.

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15
Q

What is the trachea and what is it responsible for?

A

The trachea (also known as the windpipe) directs the flow of air into and out of the lungs.

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16
Q

What do the rings of cartilage around the trachea prevent?

A

Fast moving air is at low pressure which could leave the trachea at risk of collapsing. This is prevented by the rings of cartilage.

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17
Q

How many bronchi are there in the respiratory system?

A

Two, one going to each lung.

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18
Q

What is the function of the two bronchi?

A

They direct air into the lungs.

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19
Q

What are the bronchi supported by?

A

They are supported by rings of cartilage to prevent them from collapsing.

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20
Q

What are the bronchioles?

A

Bronchioles are small branches of the bronchi.

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21
Q

Where do the bronchioles end?

A

At the alveoli (air sacs).

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22
Q

What are the alveoli?

A

The alveoli are tiny air sacs that are the site of gas exchange.

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23
Q

(5 points)

What are some of the adaptations of alveoli?

A
  • They have very thin walls, allowing gases to diffuse more quickly.
  • They have a good blood supply, maximising the amount of oxygen that can be absorbed and carbon dioxide excreted.
  • They have elastic walls that enable exhalation to be a passive process through recoiling.
  • They are very numerous, giving them a large surface area.
  • They are moist. Moisture enables gases to dissolve and diffuse more quickly into the bloodstream and vice versa.
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24
Q

What are the lungs?

A

The lungs are very large, elastic, spongy organs specialised for gas exchange. They are attached to the inside of, and protected by, the rib cage.

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25
What are the lungs attached to?
They are attached to the inside of, and protected by, the rib cage.
26
What is the diaphragm?
A sheet of muscle that seals off the bottom of the rib cage and separates it from the abdomen.
27
What is the function of the diaphragm?
It functions in inhalation, contracting and moving downwards into the abdomen. It does not take part in exhalation.
28
What are the pleural membranes?
The pleural membranes are a two-membrane structure that covers the lungs and are attached to the inside of the rib cage.
29
What is the very thin space in-between the pleural membranes and the rib cage called?
The pleural cavity.
30
What is the pleural cavity filled with and what does this allow for?
The pleural cavity is filled with a fluid that allows friction-free movement between the two membranes during breathing.
31
What are the intercostal muscles?
Muscles in-between each rib.
32
What occurs to the rib cage when the intercostal muscles contract?
They cause the rib cage to move upwards and outwards increasing the volume of the chest cavity. This causes air to rush into the lungs.
33
What is the rib cage?
A series of 12 pairs of ribs that provides the support for breathing.
34
How many pairs of true ribs are there and where are they attached?
Seven pairs, and they are directly attached to the sternum.
35
How many pairs of false ribs are there, and where are they attached?
Three pairs, and they are attached to the sternum by cartilage.
36
How many pairs of floating ribs are there, and are they attached to the sternum?
Two pairs, and they are not attached to the sternum.
37
What is diffusion?
The movement of molecules from a region of high concentration to a region of low concentration.
38
How do gases move in and out of the lungs?
By ventilation - the process of inhalation and exhalation.
39
What are the main gases involved in gas exchange?
Oxygen, carbon dioxide and water vapour.
40
Why do the cells of the body need a constant supply of oxygen?
In order to carry out vital processes such as respiration.
41
# (3 points) How does oxygen transfer from the lungs into the bloodstream?
* Oxygen is inhaled into the alveolus where there is a film of moisture. * The oxygen gas dissolves into the moisture and then through the endothelial wall of the alveolus and into the bloodstream (capillary). * The oxygen moves into the red blood cells.
42
What is most oxygen carried by?
Haemoglobin within the red blood cell, although a small amount is dissolved in the plasma.
43
What waste gas is produced as a result of respiration?
Carbon dioxide, which needs to be excreted as it is an acidic gas.
44
How is carbon dioxide carried through the body?
Carbon dioxide is carried dissolved in the plasma.
45
How is carbon transferred from the bloodstream into the lungs?
In the lungs, carbon dioxide diffuses from the plasma through the endothelial wall of the alveolus into the film of moisture on the internal surface of the alveolus. The carbon dioxide then evaporates into the air space and is excreted out of the lungs.
46
How much oxygen and carbon dioxide does inhaled air contain?
21% oxygen and 0.04% carbon dioxide.
47
How much oxygen and carbon dioxide does exhaled air contain?
15% oxygen and 5% carbon dioxide.
48
What gas is excreted by the lungs, alongside carbon dioxide?
Water vapour.
49
What is breathing also known as?
External respiration.
50
What is breathing?
Breathing is the process of taking in air from the atmosphere, exchange of gases at the alveoli and exhalation of air from the lungs.
51
What is inhalation also called?
Inspiration.
52
What type of process in inhalation?
An active process involving the brain and the inspiratory muscles.
53
# (5 points) Describe the process of inhalation.
* The brain sends a signal to the inspiratory muscles, which are the intercostal muscles and the diaphragm. * The intercostal muscles contract once they recieve this signal, causing the rib cage to move upwards and outwards. * The diaphragm contracts once it recieves this signal, causing th it to move down. * The volume of the thorax (chest cavity) increases. * The thoracic air pressure decreases and the air rushes in.
54
What is exhalation also known as?
Expiration.
55
What type of process is exhalation?
Usually a passive process, meaning that it happens by itself due to the recoiling of the elastic lung tissue. However it can also be active especially during heavy exercise.
56
# (6 points) Describe the process of exhalation.
* The inspiratory muscles relax. * This causes the elastic tissue of the lungs to return to its original position. * The rib cage moves down and inwards. * The diaphragm moves upwards. * The volume of the chest decreases. * Thoracic air pressure in the lungs increases and air rushes out.
57
What is the human breathing rate determined by?
The level of carbon dioxide in the bloodstream.
58
What type of acid does carbon dioxide dissolve in the plasma to become?
Carbonic acid (a weak acid).
59
What will occur to the pH of the blood if there is too much carbon dioxide in the blood?
The pH of the blood will go down slightly.
60
What are extremely sensitive to very small changes in the blood pH?
Chemoreceptors.
61
# (3 points) How do chemoreceptors increase the breathing rate?
* When the pH decreases (becomes more acidic), the chemoreceptors send an electrical impulse to the brain telling it to increase the breathing rate. * This causes more carbon dioxide to be excreted. * The pH of the blood will then go back to normal.
62
Name a breathing disorder.
Asthma | (Or bronchitis)
63
# (5 points) What is the cause of this breathing disorder?
* Asthma is caused by inflammation of the bronchioles. * When they become inflamed, they narrow and can close completely causing an asthma attack. * Inflammation of the bronchioles can be brought about by a number of external factors such as pollen, dust or air pollution. * It can also be caused by exercise, which is a very common form. * Asthma can also be caused by breathing in cold air.
64
# (2 points) How can you prevent this breathing disorder?
* Avoid allergens such as pollen, dust or air pollution. * In the case of exercise-induced asthma, use an inhaler that keeps the bronchioles open.
65
# (3 points) What is the treatment for this breathing disorder?
* An inhaler is used to treat an asthma attack. * Inhalers use drugs called bronchodilators such as salbutamol. * These cause the constricted bronchioles to widen.
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