# Short-Questions

Fast solutions for complex problems

## How do thin walls help gas exchange?

Gas exchange in the lungs thin walls (just one cell thick) to reduce the diffusion distance. moist surface for the dissolving of gases in alveolar air so that they can diffuse across the alveolar walls. rich blood supply to remove diffused gases and maintain a concentration gradient for further diffusion.

## How do gases pass across the wall of the alveoli?

The gases move by diffusion from where they have a high concentration to where they have a low concentration: oxygen diffuses from the air in the alveoli into the blood. carbon dioxide diffuses from the blood into the air in the alveoli.

Why does the alveoli have thin walls?

The alveoli are lined with mucus and are surrounded by a network of blood capillaries. They have very thin walls for gases to be absorbed through. An individual air sac is called an alveolus. The layer of moisture in the alveoli allows gases to dissolve so that they can diffuse quickly.

### What is very thin walled and the exchange of gases takes place through it?

Gas exchange occurs in microscopic dead-end air-filled sacs called alveoli, where a very thin membrane (called the blood-air barrier) separates the blood in the alveolar capillaries (in the walls of the alveoli) from the alveolar air in the sacs.

### When the gas exchanges are being made?

When the gas exchanges are being made between the blood and the body exterior, it is called? external respiration. You just studied 10 terms!

Why do gas exchange surfaces need to be thin?

A respiratory surface is covered with thin, moist epithelial cells that allow oxygen and carbon dioxide to exchange. Those gases can only cross cell membranes when they are dissolved in water or an aqueous solution, thus respiratory surfaces must be moist.

## Are alveoli one cell thick?

a) The alveoli wall (and the capillary wall) is only one cell thick so there is only a short distance over which diffusion takes place (short diffusion pathway) so there is a faster rate of diffusion of oxygen from alveoli into the blood.

## What transports gases in the bloodstream?

Chapter Review. Oxygen is primarily transported through the blood by erythrocytes. These cells contain a metalloprotein called hemoglobin, which is composed of four subunits with a ring-like structure. Each subunit contains one atom of iron bound to a molecule of heme.

What is thinning of the walls of alveoli?

Emphysema is a condition that involves damage to the walls of the air sacs (alveoli) of the lung. Alveoli are small, thin-walled, very fragile air sacs located in clusters at the end of the bronchial tubes deep inside the lungs.

### What are the 4 phases of gas exchange?

Terms in this set (4)

• Breathing. • Inhale. Diaphragm moves down, chest volume. increases, air enters lungs.
• Exhale. Diaphragm moves up, chest volume. decreases, air leaves lungs.
• O2 & CO2 Transport. O2. rich blood goes from lungs to cells. CO2.
• Internal Respiration. Exchange of O2 & CO2 between capillaries & body cells.

### What are the phases of gas exchange in humans?

Three processes are essential for the transfer of oxygen from the outside air to the blood flowing through the lungs: ventilation, diffusion, and perfusion.

What is the only site of gas exchange?

Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.

## How are gases taken away from the lungs?

Permeable walls – allow gases to pass through. Extensive blood supply – ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.

## How are gases passed through the respiratory system?

Moist walls – gases dissolve in the moisture helping them to pass across the gas exchange surface. Permeable walls – allow gases to pass through. Extensive blood supply – ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.

How are alveoli used to increase surface area?

Large surface area – many alveoli are present in the lungs with a shape that further increases surface area. Thin walls – alveolar walls are one cell thick providing gases with a short diffusion distance. Moist walls – gases dissolve in the moisture helping them to pass across the gas exchange surface.

### What kind of substances pass through the capillary walls?

The capillary walls keep large structures such as red blood cells inside the capillary. Other substances such as oxygen, carbon dioxide, glucose (sugar), and water can pass through. Click to see full answer.