Respiratory Structure/Function

Question 1

What is the main pump muscle for mammals in the respiratory system?

Answer 1

The diaphragm is the main pump muscle for mammals.

Question 2

How do reptiles facilitate air movement?

Answer 2

Reptiles use their chest walls and intercostal muscles for air movement.

Question 3

What is the role of the diaphragm and intercostals in mammals?

Answer 3

They help in air movement and ventilation, which is important for gas exchange in the lungs.

Question 4

Describe the flow of blood in the respiratory system.

Answer 4

Blood comes from the heart, is relatively unoxygenated, goes to the lungs to become oxygenated, returns to the heart, and is then distributed to tissues.

Question 5

What is convection in the context of the respiratory system?

Answer 5

Convection is the bulk flow of molecules moving from one point to another in mass, occurring in upper airways and blood.

Question 6

What is diffusion in the respiratory system?

Answer 6

Diffusion is the movement of molecules down a concentration gradient and in response to an electrochemical potential.

Question 7

What is the significance of the alveolus in gas exchange?

Answer 7

The alveolus is where gas exchange begins, with a very thin barrier facilitating rapid diffusion of oxygen and carbon dioxide.

Question 8

What is the diameter of the barrier between the alveolus and blood?

Answer 8

The barrier is approximately 0.0001 meters, or 0.1 micrometers.

Question 9

What happens to oxygenated blood after it leaves the lungs?

Answer 9

The heart pumps the oxygenated blood out to the body’s tissues.

Question 10

What is dead space in the respiratory system?

Answer 10

Dead space refers to areas where no gas exchange occurs, such as the nasal passages, pharynx, larynx, trachea, and larger bronchi.

Question 11

Where does gas exchange primarily occur in the lungs?

Answer 11

Gas exchange primarily occurs in the alveolar sacs, which are clusters of alveoli.

Question 12

What is the total cross-sectional area of the airways as they branch?

Answer 12

The total cross-sectional area increases dramatically as the airways branch, facilitating efficient gas exchange.

Question 13

How does the surface area of the alveoli in a human lung compare to a simple balloon?

Answer 13

The surface area of the alveoli in an adult human lung is around 85 square meters, compared to just 0.1 square meters for a simple 4-liter balloon.

Question 14

What is the estimated alveolar lung surface area in a horse?

Answer 14

The estimated alveolar lung surface area in a horse is about 2,500 square meters.

Question 15

What happens to the velocity of gas flow as the total cross-sectional area increases?

Answer 15

As the total cross-sectional area increases, the velocity of gas flow decreases.

Question 16

How does the analogy of a river relate to gas flow in the lungs?

Answer 16

Just like a river narrows and speeds up, gas flow slows down as it enters the vast cross-sectional area of the alveoli.

Question 17

What happens to gas flow velocity in the alveoli?

Answer 17

The gas flow velocity approaches zero as it reaches the millions of alveoli due to the vast cross sectional area.

Question 18

What occurs when bulk flow slows down in the lungs?

Answer 18

Diffusion takes over, allowing oxygen to efficiently diffuse into the blood and carbon dioxide to diffuse out.

Question 19

How does rapid breathing affect gas exchange?

Answer 19

Despite rapid breathing, gas exchange occurs in a calm environment at the molecular level.

Question 20

What is the primary mechanism of gas transport in terminal bronchioles?

Answer 20

Gas primarily moves by convection or bulk flow in the terminal bronchioles.

Question 21

What happens to gas flow as airways open into alveoli?

Answer 21

Bulk flow essentially stops, and diffusion takes over as the gas moves down its electrochemical potential.

Question 22

What is the highest point of resistance to blood flow in the cardiovascular system?

Answer 22

The highest point of resistance occurs in the arterioles.

Question 23

Where does the highest resistance to airflow occur in the respiratory system?

Answer 23

The highest resistance occurs in the medium sized bronchi, roughly at generations 3, 4, and 5.

Question 24

Why do medium sized bronchi have the highest resistance?

Answer 24

They are small enough to offer significant individual resistance but not numerous enough to drastically reduce total resistance.

Question 25

What is the impact of airway diameter and number on resistance?

Answer 25

Smaller airways have higher individual resistance, but numerous small bronchioles in parallel reduce overall resistance.

Question 26

What is a common target for anti-asthma medications?

Answer 26

Medium sized bronchioles are often targeted to open up these specific airways and reduce resistance.