Respiratory System

Question 1

What is the respiratory system involved in?

Answer 1

Exchange of gases (O2 and CO2) between the air and the blood, transport of air to and from the gaseous exchange surface, regulation of the pH of the blood, production of sound and the sense of smell.

Question 2

What does the mammalian respiratory system consist of?

Answer 2

Lungs in the thoracic cavity, air passageways leading to the lungs, pleural sacs lining the thorax and covering the lungs.

Question 3

What do pleural sacs do?

Answer 3

They reduce friction during breathing movements.

Question 4

What do nostrils do?

Answer 4

They act as an entrance to the nasal cavity and respiratory system, nostrils can be more pliable and dilatable in an active animal like a horse and more rigid in a less active animal like a pig.

Question 5

What is the nasal cavity?

Answer 5

A large cavity lined with mucous membrane that is moist and vascular. The nasal cavity is located above the hard palette and inside the nose. The nasal cavity filters and cleans air as well as moistening and warming incoming air.

Question 6

What is the pharynx?

Answer 6

A common passage for air and ingested materials like food. A flap of cartilage called the epiglottis prevents food from entering the larynx and trachea during swallowing.

Question 7

What is the larynx?

Answer 7

A muscular cartilaginous structure that serves as the principal organ of sound production and contains the vocal cords. It’s also known as the voice box.

Question 8

What is the trachea?

Answer 8

A tube that’s kept open by the presence of c-shaped rings of cartilage in its walls. The mucous membrane of the trachea is ciliated. The mucus in the trachea trap dust (or other air particles) and the cilia beat to move the mucus along and out of the trachea.

Question 9

What are bronchi?

Answer 9

These are the main branches from the trachea that are similar in structure to it. The two tubes carry air from the trachea to each lung.

Question 10

What are bronchioles?

Answer 10

These are fine passageways formed by branching from the bronchi. The larger bronchioles posses both cartilage and muscle in their walls, the smaller ones have walls of muscle only. These muscles allow constriction and dilation of the airway to occur.

Question 11

What are alveoli?

Answer 11

The lead into numerous microscopic sacs called alveoli, this is where gaseous exchange takes place. When there are microbes in the alveoli, macrophages ingest these and travel back up the lungs to be coughed up.

Question 12

What is the flap of cartilage that prevents food/water from entering the larynx and trachea called?

Answer 12

The epiglottis.

Question 13

Where is the hard palette located?

Answer 13

It is the roof of the mouth, above the tongue.

Question 14

Where is the soft palette located?

Answer 14

At the back of the throat.

Question 15

Why do alveoli give a huge advantage to the lungs?

Answer 15

They provide a much larger surface area so the more gaseous exchange can occur in each breath. How

Question 16

What is the composition of alveoli?

Answer 16

A single layer of cells, a thin film of fluid on the lining and are in close contact with blood capillaries.

Question 17

What means does the gaseous exchange between the alveoli and the blood capillaries occur?

Answer 17

Diffusion. The air in the alveoli is high in oxygen while the blood in the capillaries around the alveoli is low in oxygen. Oxygen, therefore, diffuses into the blood from the alveoli. The blood around the alveoli has a much higher carbon dioxide concentration than the air within the alveoli. Carbon dioxide, therefore, diffuses from the capillaries into the alveoli to be removed when the lungs exhale.

Question 18

How is oxygen transported in the blood?

Answer 18

Approximately 9% of it is carried by combining with haemoglobin in the red blood cells.

Question 19

How is carbon dioxide transported in the blood?

Answer 19

In a number of different ways, about 70% is carried as bicarbonate ions in the blood plasma, approximately 25% combines with haemoglobin in the red blood cells, the rest is dissolved in the blood plasma.

Question 20

What is inspiration also known as?

Answer 20

Inhalation or breathing in.

Question 21

What is expiration also known as?

Answer 21

Exhalation or breathing out.

Question 22

How does inspiration occur?

Answer 22

The diaphragm (the principal muscle involved) contracts and flattens, and the muscles of the chest wall contract to move the rib outwards. All of these movements increases the volume of the thorax and this causes the lungs to expand. As the volume of the lungs increases, the pressure within the lungs decreases. This draws air into the lungs.

Question 23

How does expiration occur?

Answer 23

It is a largely passive process as the lungs are being put back into their natural state. The respiratory muscles relax and the volume of the thoracic cavity decreases. The elasticity of the lungs allows them to recoil and reduce in volume. The pressure within the lungs increases as the air is pushed out of the lungs.

Question 24

What is the diaphragm?

Answer 24

A muscle underneath the lungs that helps with breathing.

Question 25

What does forced inspiration involve?

Answer 25

It involves the respiratory muscles (diaphragm and external intercostal muscles) plus the accessory muscles (muscles in neck and shoulders).

Question 26

What does forced expiration involve?

Answer 26

It involves the abdominal muscles.

Question 27

How is Tidal Volume defined?

Answer 27

The volume of air inhaled or exhaled during normal, quiet breathing.

Question 28

How is Minute Volume defined?

Answer 28

The volume of air inhaled per minute.

Question 29

How is Total Lung Capacity defined?

Answer 29

The volume of air contained in the entire respiratory system.

Question 30

How is respiration controlled?

Answer 30

It is largely subconscious and is controlled by bt respiratory centres in the brain (specifically in the brainstem). These centres signal the respiratory muscles to relax or contract.

Question 31

What is the pleural space?

Answer 31

A space between the pleural membrane and the lungs.

Question 32

What is the structure of the trachea?

Answer 32

Tracheal cartilage ring in a c shape. Opening of c is dorsal with the gap being filled with tracheal smooth muscle. Inside the tube is mucous membrane.

Question 33

How will an increase or excessive amount of CO2 in the blood affect breathing?

Answer 33

Breath rate will increase.

Question 34

How does increased body temperature affect breathing?

Answer 34

Breath rate will increase.

Question 35

How is apnoea defined?

Answer 35

When breathing temporarily stops.

Question 36

How does air flow through an avian respiratory system?

Answer 36

To inhale the air enters the trachea, goes to bronchi, goes to posterior air sacs, the air is pushed by constriction of air sacs through the parabronchi tubes and into the lungs. Gas exchange occurs in the lungs. To exhale the air flows into the anterior air sacs, the air then exits the sacs via the bronchi, then out the trachea while fresh air is pushed through the lungs.

Question 37

What’re the 3 major differences between bird and mammal respiratory systems?

Answer 37

1) Birds have no diaphragm, mammals do. 2) Birds have small, non-distensible lungs, mammals have larger, very distensible lungs. 3) In birds, the lungs only have one direction of airflow, in mammals, the lungs have 2 directions (in and out).