Chapter 6: The Respiratory System

Question 1

Thoracic cavity

Answer 1

Structure of which is specifically designed to perform breathing

Question 2

Anatomy of the respiratory system

Answer 2

Question 3

Pharynx

Answer 3

Resides behind the nasal cavity and at the back of the mouth, it is a common pathway for both air destined for the lungs and food destined for the esophagus.

Question 4

Larynx

Answer 4

Lies below the pharynx and is only a pathway for air.

Question 5

Glottis

Answer 5

The opening of the larynx

Question 6

Epiglottis

Answer 6

Covers the opening of the larynx (glottis) during swallowing.

Question 7

Vocal cords

Answer 7

There are two of them, contained in the larynx, that are maneuvered using skeletal muscle and cartilage.

Question 8

Trachea

Answer 8

Passageway for air, cartilaginous tube located after the larynx.

Question 9

Bronchi

Answer 9

Two mainstream tubes located after the trachea.

Question 10

Bronchioles

Answer 10

Smaller divisions of the bronchi.

Question 11

Alveoli

Answer 11

Tiny balloon likes structures in which gas exchange occurs

Question 12

Surfactant

Answer 12

A detergent that lower surface tension. Prevents the alveolus from collapsing on itself.

Interesting. Premature infants lack surfactant. Premature infants with respiratory distress are often placed on ventilators. Often, the ventilators are set to provide positive end expiratory pressure to prevent the alveolus from collapsing on itself.

Question 13

Lung membranes

Answer 13

Known as pleurae. Forms of closed sack against which the lung expands.

Question 14

Visceral pleura

Answer 14

The membrane surface adjacent to the lung.

Question 15

Parietal pleural

Answer 15

Outer membrane closest to the chest wall

Question 16

Intrapleural space

Answer 16

Space between the parietal and visceral pleura. Contains a thin layer of fluid That helps lubricate the two pleural surfaces. We use pressure differentials between the intrapleural space and the lungs to drive air into the lungs.

Question 17

Diaphragm

Answer 17

A thin muscular structure that divides the thoracic cavity (chest) from the abdominal cavity. The diaphragm is under somatic control, even though breathing itself is under autonomic control.

Question 18

Inhalation

Answer 18

Active process using our diaphragm as well as the external intercostal muscles. As the diaphragm flattens and the chest wall expands outward, the intra-thoracic volume increases. The volume of the intraplural space increases first, leading to a decrease in intrapleural pressure. (Boyle’s law - increase volume equals decreased pressure). Now that the intraplural space has a lower pressure, the lungs will expand into the intrapleural space and the pressure of the lungs will drop. This causes air to be sucked in from a high-pressure environment – the outside world.

Question 19

External intercostal muscles

Answer 19

One of the layers of muscles between the ribs, used along with the diaphragm to inhale.

Question 20

Intrathoracic volume

Answer 20

The volume of the chest cavity.

Question 21

Negative pressure breathing

Answer 21

Mechanism of inhalation. Volume of intrapleural space increases, reducing pressure, causing the lungs to increase in volume and reduce in pressure, causing the outside world (higher pressure) to fill the lungs with air.

Question 22

Emphysema

Answer 22

Disease characterized by the destruction of the alveolar walls. This results, and reduced elastic recoil of the lungs, making the process of exhalation extremely difficult.

Question 23

Internal intercostal muscles

Answer 23

Oppose the external intercostals and pull the rib cage down, we can use these muscles to speed the process of exhalation during active tasks. Otherwise exhalation is a passive process, facilitated by simple relaxation of the external intercostal muscles.

Question 24

Spirometer

Answer 24

Instrument used to measure lung capacities and volumes. Cannot measure the amount of air remaining in the lungs after complete exhalation (residual volume).

Question 25

Residual volume (RV)

Answer 25

Amount of air remaining in the lung after complete exhalation.

Question 26

Total lung capacity (TLC)

Answer 26

The maximum volume of air in the lungs when one inhales completely, usually around 6 to 7 L.

Question 27

Vital capacity (VC)

Answer 27

The difference between the minimum and maximum volume of air in the lungs.

Total lung capacity (TLC) - residual volume (RV)

Question 28

Tidal volume (TV)

Answer 28

The volume of air inhaled or exhaled in a normal breath.

Question 29

Expiratory reserve volume (ERV)

Answer 29

The volume of additional that can be forcibly exhaled after a normal exhalation.

Question 30

Inspiratory reserve volume (IRV)

Answer 30

The volume of additional air that can be forcibly inhaled after a normal inhalation.

Question 31

Graph of lung capacities and volumes

Answer 31

Question 32

Pulmonary arteries

Answer 32

Originate from right ventricle of the heart, brings deoxygenated blood to the capillaries of the pulmonary circuit.

Question 33

Pulmonary veins

Answer 33

Returns oxygenated blood to the left atrium of the heart to be pumped to the systemic circuit via the left ventricle

Question 34

Gas exchange from the alveolus

Answer 34

Question 35

Thermoregulation

Answer 35

Regulation of body temperature.

Question 36

Vasodilation

Answer 36

Widening of blood vessels.

Question 37

Vasoconstriction

Answer 37

Narrowing of blood vessels

Question 38

Functions of the respiratory system

Answer 38

Gas exchange
Thermoregulation
Immune function
Control of pH

Question 39

Immune function of the respiratory system

Answer 39

The lungs provide a large interface for the body to interact with the outside world. The lungs need to have a mechanism of fighting off infection from pathogens such as bacteria, viruses, and fungi.

Utilizing a multi-layered system of physical barriers like mucus and cilia, along with resident immune cells that identify and neutralize foreign substances, essentially protecting the lungs from infection through both innate and adaptive immune responses. Presence of macrophages (alveolar macrophages), dendritic cells (process antigens and present them to other immune cells), mast cells (histamine and inflammation), natural killer cells (innate, granulated, general defense), T cells (cell mediated adaptive immunity).

Question 40

Lysozyme

Answer 40

Enzyme found in the nasal cavity as well as in tears and saliva. Able to attack the peptidoglycan walls of bacteria.

Question 41

Mucociliary escalator

Answer 41

Mechanism of cilia in the respiratory tract that traps particulates and moves mucous to the oral cavity where it can be expelled or swallowed.

Question 42

Macrophages

Answer 42

Cells that can engulf and digest pathogens and signal to the rest of the immune system that there is an invader. Macrophages are a part of the immune system and are found in the alveoli of the lungs.

Question 43

Mast cells

Answer 43

Cells that contain pre formed antibodies on their surfaces. Mast cells release inflammatory chemicals into the surrounding area that promote an immune response. Mast cells, unfortunately, react to substances such as pollen and mold so mast cells also provide inflammatory chemicals that mediate allergic reactions.

Question 44

Control pH in the respiratory system

Answer 44

The respiratory system plays a role in pH balance through the bicarbonate buffer system.

Increased respiration decreases CO2, shifting the system to the left, increasing pH.

Decreased respiration increases CO2, shifting the system to the right, decreasing pH.

Question 45

Bicarbonate buffer system

Answer 45

Question 46

Le Chatelier’s Principle

Answer 46

A change in one of the variables that describe a system at equilibrium produces a shift in the position of the equilibrium that counteracts the effect of this change.

Question 47

Acidemia and the body’s reaction to

Answer 47

Normal pH of the body is 7.35 to 7.45. When hydrogen ion concentrations are high, the body is said to be in acidemia. Acid detecting chemoreceptors just outside of the blood brain barrier send signals to the brain to increase respiratory rate. Also, an increase in H+ ions will shift the bicarbonate buffer to create more CO2. The increase in CO2 will also trigger chemoreceptors in the brain to increase respiratory rate.

Question 48

Alkalemia

Answer 48

When the blood is too basic, the body is said to be in alkalemia. The body will seek to increase acidity. The bicarbonate buffer will shift to make more H+ and bicarbonate. Chemoreceptors in the blood brain barrier will trigger the brain to slow respiration.

Slow respiration, more CO2, shift right, more acid, lower pH.

Question 49

Alkalemia and how the body reacts

Answer 49

When the blood is too basic, the body is said to be in alkalemia. The body will seek to increase acidity. The bicarbonate buffer will shift to make more H+ and bicarbonate. Chemoreceptors in the blood brain barrier will trigger the brain to slow respiration.