Biology Stage 8: Unit 1 Respiration

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Questions and Answers

What is the primary function of the diaphragm muscle during breathing?

To contract and flatten, increasing the size of the chest and allowing air to rush in through the nose or mouth.

What are the two main organs that receive air from the bronchi?

Lungs

What is the role of the intercostal muscles during inspiration?

To pull the chest walls up and out, increasing the size of the chest and allowing air to enter the lungs.

Where does gas exchange occur in the respiratory system?

Alveoli Signup and view all the answers

What is the pathway of air through the respiratory system?

Mouth/nose → larynx → trachea → bronchus (bronchi) → bronchiole → alveoli Signup and view all the answers

What is the function of the bronchi?

To branch into smaller bronchioles and direct air to the lungs. Signup and view all the answers

What is the function of the thin layer of moisture on the inner surface of the alveoli?

Oxygen dissolves in this layer and then diffuses through the thin walls of the alveolus and capillary. Signup and view all the answers

What happens to the pressure inside the lungs when the diaphragm and intercostal muscles contract?

The pressure inside the lungs falls. Signup and view all the answers

What is the significance of the large surface area of the alveoli?

It allows for a large amount of oxygen to diffuse into the blood quickly. Signup and view all the answers

What is the definition of an organ?

A group of tissues adapted to perform a specific function. Signup and view all the answers

What is the main difference in the oxygen content between inhaled and exhaled air?

Inhaled air has 21% oxygen, while exhaled air has 16% oxygen. Signup and view all the answers

How would you test for the differences between inhaled and exhaled air?

By comparing the oxygen and carbon dioxide content of inhaled and exhaled air using a gas analyzer. Signup and view all the answers

What is the process of respiration, and what is its purpose?

Respiration is the process of releasing energy from digested food in the presence of oxygen, and its purpose is to provide energy for the body's functions. Signup and view all the answers

What is the byproduct of aerobic respiration?

Carbon dioxide and water are the byproducts of aerobic respiration. Signup and view all the answers

What do you need to do to get more oxygen?

Breathe in more deeply and frequently to take in more oxygen. Signup and view all the answers

What is the role of the respiratory system in the body?

The respiratory system brings oxygen into the body and removes carbon dioxide. Signup and view all the answers

What happens to the diaphragm when you breathe in?

The diaphragm contracts and moves down. Signup and view all the answers

What happens to the intercostal muscles when you breathe out?

They relax, allowing the ribs to move in and down. Signup and view all the answers

What is the function of the alveoli in the lungs?

They are the site of gas exchange between the air and the blood stream. Signup and view all the answers

Why do the alveoli have thin walls?

To bring air and blood as close together as possible, facilitating gas exchange. Signup and view all the answers

What happens to the air in the lungs when you breathe out?

The air is pushed up the trachea and out through the nose or mouth. Signup and view all the answers

What is the role of the diaphragm in the breathing process?

It contracts and relaxes to expand and deflate the chest cavity, facilitating breathing. Signup and view all the answers

What is the purpose of the capillaries surrounding the alveoli?

They allow gases to pass through the thin walls of each alveolus and into the blood stream. Signup and view all the answers

What is the result of the vibrations felt in the larynx when humming?

The vibrations are due to the movement of air through the vocal cords. Signup and view all the answers

Study Notes

The Human Respiratory System

The human respiratory system consists of organs such as the nose, mouth, larynx, trachea, bronchi, bronchioles, lungs, diaphragm, and intercostal muscles.
The function of these organs is to bring air into the body and facilitate the exchange of oxygen and carbon dioxide.

Pathway of Air Through the Respiratory System

Air enters the body through the nose or mouth.
From there, it passes through the larynx, trachea, bronchi, bronchioles, and finally reaches the alveoli.
In the alveoli, oxygen is absorbed into the bloodstream and carbon dioxide is removed.

The Role of Muscles in Respiration

When you breathe in, the intercostal muscles contract, pulling the chest walls up and out.
The diaphragm muscle also contracts, increasing the size of the chest cavity and allowing air to rush in.
When you breathe out, the intercostal muscles relax, causing the chest walls to move in and down.
The diaphragm muscle also relaxes, reducing the size of the chest cavity and pushing air out.

Larynx and Vibration

The larynx (voice box) vibrates when you make a loud humming sound.
This is because the vocal cords in the larynx are vibrating to produce sound.

Gas Exchange at the Alveoli

The alveoli are tiny air sacs inside the lungs where gas exchange occurs.
The alveoli are covered in tiny capillaries (blood vessels) that allow gases to pass through.
Oxygen from the inhaled air diffuses into the bloodstream, while carbon dioxide is removed from the bloodstream and exhaled.

Adaptations of the Alveolus

The alveoli have thin walls to bring air and blood close together.
The inner surface is covered with a thin layer of moisture to facilitate the diffusion of oxygen.
The large surface area of the alveoli (approximately 300 million) allows for efficient gas exchange.

Differences Between Inhaled and Exhaled Air

Inhaled air contains 21% oxygen, 0.04% carbon dioxide, and a small amount of water vapor.
Exhaled air contains 16% oxygen, 4% carbon dioxide, and a large amount of water vapor.
The main differences between inhaled and exhaled air are the concentration of oxygen and carbon dioxide.

Respiration and Energy

Respiration is the process by which the body releases energy from digested food (glucose) in the presence of oxygen.
The energy released is used to keep us alive, stay warm, grow, reproduce, and move.
To get more oxygen, you need to breathe in more deeply and frequently.