Gas exchange in humans

Question 1

What is the process of moving air in and out of our lungs called?

Answer 1

Ventilation

Question 2

What is the structure that protects internal organs such as lungs?

Answer 2

Ribs

Question 3

What are the muscles between the ribs that control their movement called?

Answer 3

Intercostal muscles

Question 4

What is the sheet of connective tissue and muscle at the bottom of the thorax?

Answer 4

Diaphragm

Question 5

What is the windpipe that connects the mouth and nose to the lungs?

Answer 5

Trachea

Question 6

What is the voice box also known as?

Answer 6

Larynx

Question 7

What are the two large tubes branching off the trachea, one for each lung, called?

Answer 7

Bronchi

Question 8

What are the smaller tubes that split from the bronchi and connect to the alveoli?

Answer 8

Bronchioles

Question 9

What are the tiny air sacs where gas exchange takes place?

Answer 9

Alveoli

Question 10

What is the fluid-filled space that reduces friction and allows lungs to move freely?

Answer 10

Pleural Cavity

Question 11

Fill in the blank: The thorax is the whole structure of the _______.

Answer 11

chest

Question 12

What is inhalation?

Answer 12

Breathing in

Inhalation involves the contraction of certain muscles to draw air into the lungs.

Question 13

What happens to the external intercostal muscles during inhalation?

Answer 13

They contract

This contraction moves the ribs up and out.

Question 14

What is the role of the diaphragm during inhalation?

Answer 14

Contracts and moves down, flattening

This action increases the volume of the thorax.

Question 15

What effect does inhalation have on thoracic volume?

Answer 15

Increases

An increase in thoracic volume leads to a decrease in pressure.

Question 16

What causes air to move into the thorax during inhalation?

Answer 16

Pressure in the thorax is lower than pressure outside

This pressure difference allows air to flow in.

Question 17

What is exhalation?

Answer 17

Breathing out

Exhalation involves the relaxation and contraction of specific muscles.

Question 18

What happens to the external intercostal muscles during exhalation?

Answer 18

They relax

The internal intercostal muscles contract during this process.

Question 19

What is the role of the diaphragm during exhalation?

Answer 19

Relaxes and moves up, becoming dome shaped

This contributes to the decrease in thoracic volume.

Question 20

What effect does exhalation have on thoracic volume?

Answer 20

Decreases

A decrease in thoracic volume results in an increase in pressure.

Question 21

What causes air to move out of the thorax during exhalation?

Answer 21

Pressure in the thorax is higher than pressure outside

This pressure difference allows air to flow out.

Question 22

What is the composition of inhaled air compared to exhaled air?

Answer 22

Inhaled air has more oxygen, exhaled air has more carbon dioxide

Additionally, exhaled air has more water vapor and is warmer.

Question 23

What is the primary function of alveoli?

Answer 23

Site of gas exchange by diffusion

Alveoli facilitate the exchange of oxygen and carbon dioxide.

Question 24

What happens to oxygen and carbon dioxide during gas exchange in the alveoli?

Answer 24

Oxygen diffuses from alveoli into blood; carbon dioxide diffuses from blood to alveoli

This process is essential for respiration.

Question 25

How are alveoli adapted to increase the rate of diffusion?

Answer 25

They are millions of small, rounded sacs ## Footnote This increases the surface area to volume ratio and they are also highly folded.

Question 26

What is the thickness of alveoli and capillary walls?

Answer 26

Only 1 cell thick ## Footnote This thinness provides a short diffusion distance for gas exchange.

Question 27

What factors create a steep concentration gradient for O2 and CO2?

Answer 27

Ventilation and a rich blood supply ## Footnote These factors enhance the efficiency of gas exchange in the lungs.

Question 28

What role does the layer of moisture on the surface of alveoli play?

Answer 28

Helps gases to dissolve for diffusion ## Footnote This moisture facilitates the crossing of gases through the alveolar membrane.

Question 29

What are carcinogens found in cigarettes?

Answer 29

Tar, nicotine, and carbon monoxide ## Footnote Tar is known to cause cancer, nicotine is highly addictive, and carbon monoxide affects oxygen transport in the blood.

Question 30

What happens to the alveoli in emphysema?

Answer 30

Walls break down and fuse together, becoming enlarged ## Footnote This condition severely reduces the Surface Area to Volume ratio, impairing oxygen exchange.

Question 31

What is the common side effect of bronchitis?

Answer 31

Smoker's cough ## Footnote This occurs due to inflammation of bronchioles and excess mucus production.

Question 32

How does cigarette smoke affect cilia in the trachea?

Answer 32

Destroys cilia, preventing mucus clearance ## Footnote This leads to blocked air passages and increased risk of infections.

Question 33

What is lung cancer and how is it caused by smoking?

Answer 33

Mutation of cells due to tar, leading to uncontrollable division ## Footnote Tumors can form, often detected at late stages due to lack of symptoms.

Question 34

What is coronary heart disease?

Answer 34

Narrowing or blockage of arteries supplying blood to the heart ## Footnote This can lead to blood clots, heart attacks, and sudden death.

Question 35

Fill in the blank: Cigarettes contain _______ which can cause the blood to thicken and form clots.

Answer 35

Chemicals ## Footnote These chemicals contribute to cardiovascular diseases.

Question 36

What can be used to measure the release of carbon dioxide?

Answer 36

Limewater or hydrogen carbonate indicator ## Footnote Limewater turns cloudy in the presence of carbon dioxide, while hydrogen carbonate indicator turns yellow in CO2 and purple in no CO2.

Question 37

What is the method for measuring breathing rates during different levels of exercise?

Answer 37

Take the resting breath rate and then the new breath rate for each minute after exercising ## Footnote This method helps to observe changes in breathing rates due to exercise.

Question 38

What are some control variables in the investigation of breathing during exercise?

Answer 38

* Size * Gender * Fitness * Age * Time of exercise

Question 39

Why do you breathe heavier after exercise?

Answer 39

Muscles need to respire more, requiring more oxygen and the removal of excess carbon dioxide ## Footnote Breathing heavily helps to meet the increased oxygen demand and remove CO2 produced during exercise.

Question 40

What happens if muscles do not get enough oxygen during intense or prolonged exercise?

Answer 40

They respire anaerobically, producing lactic acid ## Footnote Anaerobic respiration occurs when oxygen levels are insufficient for aerobic processes.

Question 41

What is the purpose of breathing heavily after exercise?

Answer 41

To break down lactic acid using oxygen ## Footnote This process requires additional oxygen to completely oxidize the lactic acid produced during anaerobic respiration.

Question 42

What is the term for the amount of oxygen needed to completely oxidize lactic acid?

Answer 42

Oxygen debt