MSc Physiology Lecture 12: Respiratory System

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Questions and Answers

What is the primary function of the lungs?

To filter out small blood clots formed in veins

To convert angiotensin I to angiotensin II

To facilitate the exchange of oxygen and carbon dioxide (correct)

To pump blood around the body

What is the purpose of the pulmonary arteries?

To filter out gas micro-bubbles occurring in the venous blood stream

To carry oxygen-low blood from the heart to the lungs (correct)

To pump blood around the body

To carry oxygen-rich blood from the lungs to the heart

What happens to the oxygen in the air we breathe?

It is converted into carbon dioxide

It crosses from the air in the alveoli into the bloodstream (correct)

It is breathed out of the body

It stays in the lungs

What is the role of angiotensin-converting enzyme in the lungs?

It converts angiotensin I to angiotensin II Signup and view all the answers

What is another function of the lungs besides respiration?

To influence the concentration of some biologic substances and drugs in blood Signup and view all the answers

What is filtered out of the venous blood stream by the lungs?

Gas micro-bubbles Signup and view all the answers

What does Immunoglobulin-A secreted in the bronchial secretion protect against?

Respiratory infections Signup and view all the answers

What is the purpose of the pulmonary veins?

To carry oxygen-rich blood from the lungs to the heart Signup and view all the answers

What is the primary function of the respiratory system?

To supply oxygen to the blood Signup and view all the answers

Where does the exchange of gases take place in the respiratory system?

Alveoli Signup and view all the answers

What is the approximate percentage of oxygen in inspired air?

20% Signup and view all the answers

What is the primary function of the diaphragm in the respiratory system?

To ventilate the lungs Signup and view all the answers

What is the approximate percentage of carbon dioxide in expired air?

4% Signup and view all the answers

What is the main function of the bronchi in the respiratory system?

To branch into smaller bronchial tubes Signup and view all the answers

What is the process by which oxygen passes from the alveoli into the bloodstream?

Diffusion Signup and view all the answers

What is one of the principle functions of the respiratory system?

To maintain the acid-base balance of the blood Signup and view all the answers

What is the role of the lungs?

To take oxygen into the body and remove carbon dioxide Signup and view all the answers

How many lobes does the right lung have?

Three Signup and view all the answers

What are the small, pyramidal-shaped areas of the lung called?

Bronchopulmonary segments Signup and view all the answers

What is the purpose of the capillaries surrounding the alveoli?

To facilitate gas exchange between the air and blood Signup and view all the answers

What is the trachea connected to?

The left and right bronchi Signup and view all the answers

Where does gas exchange occur in the lungs?

In the alveoli Signup and view all the answers

What is the function of the bronchi?

To distribute air throughout the lungs Signup and view all the answers

How many bronchopulmonary segments are in each lung?

10 Signup and view all the answers

Study Notes

Respiratory System

The primary function of the respiratory system is to supply oxygen to the blood, which delivers oxygen to all parts of the body.
The respiratory system performs this function while breathing, exchanging oxygen and carbon dioxide through the alveoli.
The average adult's lungs contain approximately 600 million alveoli, which are surrounded by capillaries.

Principle Functions of the Respiratory System

Ventilate the lungs
Extract oxygen from the air and transfer it to the bloodstream
Excrete carbon dioxide and water vapour
Maintain the acid-base balance of the blood

Composition of Inspired and Expired Air

Inspired air: approximately 79% nitrogen, 20% O2, 0.04% CO2, and water vapour/trace gases
Expired air: approximately 79% nitrogen, 16% O2, 4% CO2, and water vapour/trace gases

Structure of the Respiratory System

Respiration takes place with the aid of the mouth, nose, trachea, lungs, diaphragm, and intercostal muscles.
Oxygen enters the respiratory system through the mouth and nose, then passes through the larynx and trachea.
The trachea splits into two bronchi, which divide into smaller bronchial tubes that lead to the alveoli.

Lungs

The lungs are paired, cone-shaped organs that take up most of the space in the chest.
They have two main functions: to take oxygen into the body and to remove carbon dioxide.
The right lung has three lobes, while the left lung has two lobes due to the heart taking up space in the left side of the chest.
The lungs can be divided into smaller portions called bronchopulmonary segments, each with its own blood supply and air supply.

Function of Alveoli

Air enters the lungs through the bronchi and eventually forms little thin-walled air sacs or bubbles called alveoli.
The alveoli are where gas exchange takes place between the air and the blood.
Capillaries surround each alveolus, allowing oxygen to diffuse from the air into the blood and carbon dioxide to diffuse from the blood into the air.

Blood Supply

The lungs receive a large blood supply from the pulmonary arteries, which carry blood low in oxygen and high in carbon dioxide.
The newly oxygen-rich blood then travels back through the pulmonary veins into the left side of the heart.

Additional Functions of the Lungs

Alter the pH of blood by facilitating alterations in the partial pressure of carbon dioxide
Filter out small blood clots formed in veins
Filter out gas micro-bubbles occurring in the venous blood stream
Influence the concentration of some biologic substances and drugs used in medicine in the blood
Convert angiotensin I to angiotensin II by the action of angiotensin-converting enzyme
Serve as a layer of soft, shock-absorbent protection for the heart

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Description

This quiz covers the primary function of the respiratory system, including the supply of oxygen to the blood and the exchange of gases at the alveoli.