Respiratory System - the system and gas exchange

Why is it important to have a constant changing in air in the alveoli?

constant changing of the air in the alveoli helps to ensure that there is always a difference in concentration of oxygen and carbon dioxide in the air and blood

What is the function of intercostal muscles?

They are muscles between the ribs. They move the rib cage upwards and outwards to increase the volume of the chest cavity and thus the lungs when breathing in.

How is the concentration gradient of oxygen and carbon dioxide maintained?

- constant flow of blood through the capillaries - movement of air into and out of the alveolus when we breath in and out

State the basic reasons why the alveoli are well suited for gas exchange.

- the alveoli give lungs a huge internal surface area - each alveolus is well supplied with blood vessels - continuous flow of blood helps to maintain a difference in concentration - membrane of alveolus is one cell thick - thin layer of moisture covers alveolus as gases can diffuse

What are the basic reasons that the lungs, different to alveoli, are suitable for gas exchange?

- the lungs are positioned deep inside the body to prevent excess evaporation of the fluid the covers the respiratory surfaces - lung volume can be changed by movements of the respiratory muscles, so that air is made to flow into and out of the lungs

Identify the order in which air travels in through the of the respiratory system.

1) Nasal cavity 2) Pharynx 3) Larynx 4) Trachea 5) Bronchi 6) Bronchioles 7) Alveoli

Describe how the concentration allows oxygen to diffuse into the bloodstream.

Blood comes into the capillaries around alveoli with a low concentration of oxygen - lower than the concentration in the air of the alveolus. Oxygen dissolves in the moisture on the inside of the alveolus and diffuse through the membrane, through the walls of the capillaries and into the blood.

During gas exchange between alveolar air and blood, state the direction of diffusion of oxygen and carbon dioxide.

Carbon dioxide diffuses into the alveolus, out of the bloodstream and oxygen diffuses into the bloodstream, out of the alveolus.

What is the function of the diaphragm?

It is a muscle that separates the chest from the abdomen. It contracts and flattens downwards, thereby increasing the volume of the chest cavity and lungs during breathing in.

What is the concentration gradient?

a difference in concentration in a solution, often between the inside and outside of a cell; also called the diffusion gradient.