2. Introduction and Anatomy of Lungs Airways and Blood Supply

Question 1

What are the functions of the respiratory system?

Answer 1

Gas exchange Acid base balance - regulation of body pH (7.4 average pH) Protection of infection Communication via speech

Question 2

Why is gas exchange essential?

Answer 2

Oxygen is essential for releasing energy Removing carbon dioxide, the waste product.

Question 3

What is the cardiovascular system responsible for?

Answer 3

Transporting oxygen to tissues Transporting carbon dioxide away from tissue

Question 4

What is meant by external respiration?

Answer 4

Movement of gases between the air and the bodies cells

Question 5

Where does the pulmonary artery take blood? (Only artery that takes deoxygenated blood)

Answer 5

Away from the heart

Question 6

Where does the pulmonary vein take blood? (Only vein that takes oxygenated blood)

Answer 6

Towards the heart

Question 7

How does pulmonary circulation differ from systemic circulation?

Answer 7

Opposite in function - It delivers CO2 to the lungs and picks up O2

Question 8

What changes occur in the respiratory system and cardiovascular system when E demand increases by working muscle?

Answer 8

Respiratory - Rate & Depth of Breathing.

Speeds up: - Substrate (O2) acquisition - Waste disposal (CO2) Cardiovascular- Heart Rate & Force of Contraction.

Speeds up: - Substrate delivery to muscle via blood - Waste removal via blood

Question 9

What is the movement of O2 during gas exchange?

Answer 9

O2 moves from inspired air to blood (at lungs) O2 moves from blood to cells (at the systemic capillaries)

Question 10

What is the movement of CO2 during gas exchange?

Answer 10

CO2 moves from blood to air which is then expired (at Lungs) CO2 moves from cells to blood (at the systemic capillaries)

Question 11

What is the relationship between the volume of oxygen exchanged in the lungs per unit time and that of the net volume exchanged in the tissues

Answer 11

EQUAL Same applies for carbon dioxide

Question 12

What is the purpose of this equal exchange between the lungs and the tissues?

Answer 12

This prevents gas build up in the circulation which would hamper gas exchange. Helps to ensure supply = demand

Question 13

What are the average volumes exchanged per minute?

Answer 13

250 ml oxygen exchanged (consumed) 200 ml carbon dioxide exchanged (produced)

Question 14

What are breathing rates at rest? And maximum breathing rate?

Answer 14

Breathing rate is 10-20 breaths/min at rest, 40 - 45 at maximum exercise in adults

Question 15

What portion of the respiratory system is shared with the digestive system?

Answer 15

The pharynx - From your nose, oxygen moves into the pharynx or throat

Question 16

What helpful roles does the nose have in the respiratory system?

Answer 16

Air enters the body through nose. Cilia and mucus trap particles Warms and moistens air

Question 17

What is the function of trachea?

Answer 17

Transports oxygen from the pharynx to the lungs

Question 18

What protective structural component exists in the trachea?

Answer 18

Stiff rings of cartilage - supports and protects

Question 19

What are lungs spongy?

Answer 19

Lots of hollow sacs that compose them

Question 20

What is the function of the epiglottis?

Answer 20

Small flap where tissue folds over the trachea and prevents food from entering it when you swallow It is mostly open, closes on swallowing

Question 21

What is the function of the larynx?

Answer 21

Contains vocal cords - vibrate to produce sound

Question 22

What is the bronchus?

Answer 22

Where the trachea bifurcates (at sternal angle), air moves from trachea to bronchus which lead to the inside of the lung.

Question 23

Where is the lower respiratory system enclosed?

Answer 23

In the thorax, bounded by the ribs, spine and the diaphram

Question 24

What body structures are found in the upper respiratory system?

Answer 24

Pharynx, Vocal Cords, Esophagus, Nasal Cavity, Tongue, Larynx

Question 25

What body structures are found in the lower respiratory system?

Answer 25

Right lung, Left lung, Left brochus and right bronchus, diaphragm

Question 26

Where do the lungs sit?

Answer 26

In the pleural cavity - contains 3 ml of fluid

Question 27

How much does each bronchi branch?

Answer 27

22 times, before finally terminating in a cluster of alveoli

Question 28

Which primary bronchi is wider?

Answer 28

The right primary bronchi - more aspirated foreign bodies lodge here

Question 29

What maintains patency (open) in the airways?

Answer 29

C - shaped rings of cartilage

Question 30

What doesn’t contain C - shaped rings of cartilage?

Answer 30

Bronchioles

Question 31

What maintains patency in the bronchioles?

Answer 31

Physical forces in the thorax

Question 32

What happens to airway diameter as you go down the respiratory tree?

Answer 32

Decreases

Question 33

Where does greatest resistance to air flow occur?

Answer 33

Upper respiratory tract (conducting zone), contains lots more molecules Branching increases surface area

Question 34

What is the effect of contraction on resistance?

Answer 34

Contraction decreases diameter = increases resistance Relaxation increases diameter = decreases resistance

Question 35

What controls airway diameter, and therefore resistance to airflow?

Answer 35

Activity of bronchial smooth muscle

Question 36

What is each cluster of alveoli surrounded by?

Answer 36

Elastic fibres and a network of capillaries

Question 37

What are the functions of the elastic fibers?

Answer 37

Stretch during inspiration, they release this stretch energy on exhalation (contraction)

Question 38

What type of cells exist in the alveoli?

Answer 38

Type 1 cells - gas exchange Type 2 cells - produce surfactant Capillaries exist between the alveoli - direct contact with type one cells - minimises distance Alveolar macrophages ingest foreign material that reaches alveolli

Question 39

Where is gas exchange possible?

Answer 39

Only at the alveoli - very thin walls

Question 40

What is the function of conducting airways?

Answer 40

The walls of the upper airways are too thick to allow gases to cross and their function is purely conduction of air to and from the alveoli (the air in these airways is known as anatomical dead space because it cannot participate in gas exchange).

Question 41

What is the function of huge surface area of the alveoli?

Answer 41

The huge surface area of the alveoli further enhances their gas exchange function.

Question 42

What lines the respiratory tract?

Answer 42

Epithelium (psuedo-stratified, ciliated, columnar) Glands Lymph nodes Blood vessels (nutritive) Ciliated Mucous

Question 43

What is the progression from the nose to alveoli?

Answer 43

Epithelium becomes more squamous Cilia lost Mucous cells lost (before cilia) Goblet cells lost before cilia, cilia are the last thing to be lost

Question 44

What is the function of mucous?

Answer 44

Moistens air Traps particles Provides large surface area for cilia to act on

Question 45

What cells are associated with mucous?

Answer 45

Goblet cells Subepithelial glands

Question 46

What is the movement of macrophages from the alveoli?

Answer 46

Macrophages escape to pharynx/lymph nodes

Question 47

What is another word for

Answer 47

Pneumocytes - rich capillary network

Question 48

Describe type 1 Pneumocytes

Answer 48

Pneumocytes - 97% alveolar surface Simple squamous epithelium Gas exchange

Question 49

Describe type 2 Pneumocytes

Answer 49

Surfactant production Phospholipids and protein Reduces surface tension at alveolar surface Reduces work of breathing