Lecture 30: Respiration 1

Question 1

Two stages of respiration

Answer 1

1. External respiration

2. Internal respiration

Question 2

External respiration

Answer 2

The entire sequence of events involved in the exchange of O2 and CO2 between the external environment and the cells of the body

Question 3

Internal respiration

Answer 3

Intracellular metabolic processes carried out within the mitochondria which use O2 and produce CO2 during the derivation of energy from nutrient molecules

Question 4

Two zones of the respiratory system

Answer 4

1. Conducting zone - brings air in and out of lungs

2. Respiratory zone - Lined with alveoli where gas exchange occurs

Question 5

what is the main airway of the conducting zone?

Answer 5

trachea

Question 6

Trachea and larger bronchiole structure

Answer 6

rigid non-muscular tubes enriched by a series of cartilaginous rings that prevent compression of the tubes

Question 7

Do the smaller bronchioles in the conducting zone have cartilage?

Answer 7

Nope

Question 8

What kind of muscle and innervation does the conducting zone have?

Answer 8

Smooth muscle

Sympathetic and parasympathetic innervations

Question 9

Sympathetic adrenergic neurons in the conducting zone

Answer 9

Activate B-adrenergic receptors in bronchial smooth muscle which creates relaxation and dilation of the airways

Question 10

Parasympathetic cholinergic neurons in the conducting zone

Answer 10

Activate muscarinic receptors which creates contraction and constriction of the airways

Question 11

How does the ANS influence resistance and airflow?

Answer 11

Changes in diameter in the conducting airways leads to changes in their resistance

Question 12

What are B adrenergic agonists like epinephrine used for

Answer 12

To dilate airways in the treatment of asthma

Question 13

4 parts of the respiratory zone

Answer 13

1. Respiratory bronchioles
2. Alveolar ducts
3. Alveolar sacs
4. Alveoli

Question 14

Respiratory bronchioles

Answer 14

• Alveoli occasionally bud off their walls
• Contains smooth muscle
• Have limited ability for gas exchanges

Question 15

Alveolar ducts

Answer 15

Respiratory bronchioles branch into many alveolar ducts which lead into microscopic air sacs called alveoli, where gas exchange takes place

Question 16

Alveolar sacs

Answer 16

A group of two or more alveoli with a common opening into an alveolar duct

Question 17

Functional unit of the lung

Answer 17

Alveoli

Question 18

Alveolar walls consists of

Answer 18

• a single layer of flattened Type 1 alveolar cells
• contains Type II alveolar cells which synthesize pulmonary surfactant which is necessary for the reduction of surface tension of alveoli
• Alveolar macrophages that keep alveoli free of debris

Question 19

Two hormones that affect Type II alveolar cells

Answer 19

• Thyroid hormone - increases their number in the wall of the alveoli
• Cortisol - enhances their maturation

Question 20

Lungs are housed in

Answer 20

Airtight thoracic cavity

Question 21

Four things the thoracic cavity is composed of

Answer 21

1. Several pairs of ribs
2. Sternum
3. Intercostal muscles between ribs
4. Thoracic vertebrae

Question 22

The only communication between thorax and atmosphere is through

Answer 22

respiratory airways into the alveoli

Question 23

Pleural sac

Answer 23

Separates each lung from thoracic wall and other surrounding structures
Double wall closed sac

Question 24

Intra-pleural fluid

Answer 24

• Secreted by pleural membranes

- Lubricates the pleural surfaces, thereby reducing friction as they slide past each other during breathing

Question 25

Two types of inflammation of the pleural sac

Answer 25

1. Dry pleurisy | 2. Wet pleurisy

Question 26

Dry pleurisy

Answer 26

- Fluid content remains unchanged by disease - Two layers of membrane may become swollen and rub against each other during breathing - Pain

Question 27

Wet pleurisy

Answer 27

- Fluid increases abnormally - Less likely to cause pain because there is usually no chaffing - Fluid may interfere with breathing

Question 28

Atmosphere exerts pressure known as

Answer 28

Barometric or atmospheric pressure

Question 29

At sea level, atmospheric pressure is equal to

Answer 29

760 mmHg

Question 30

Individual pressure exerted by a particular gas

Answer 30

Partial pressure

Question 31

Air is ____ on entering respiratory passages

Answer 31

humidified

Question 32

Partial pressure of water vapor at normal body temperature is

Answer 32

47 mmHg

Question 33

Water vapor dilutes all other gases in inspired air, thus gas pressure in the trachea =

Answer 33

760 - 47 = 713 mmHg

Question 34

PO2 of humidified tracheal air =

Answer 34

(760-47 mmHg) x 0.21 = 150 mmHg

Question 35

Changes in respiratory pressure during breathing are sometimes expressed as

Answer 35

relative pressire

Question 36

A positive or negative pressure indicates that the pressure is

Answer 36

relative to atmospheric pressure and is respectively, above or below atmospheric pressure

Question 37

When relative pressures are used, atmospheric pressure is set at

Answer 37

0

Question 38

Intra-alveolar pressure

Answer 38

- Pressure within alveoli that increases and decreases with each breath - Always equal to barometric pressure at the end of inspiration and expiration (rest period)

Question 39

Intra-pleural pressure

Answer 39

- Within pleural sac/cavity - Usually less than atmospheric pressure (-4mmHg) - Does not equilibrate because no communication between pleural cavity and atmosphere or the lungs

Question 40

Transpulmonary pressure

Answer 40

- Pressure gradient that holds the lung open | - Period of rest between breathing cycles when no air is moving into or out of the lungs

Question 41

If intrapleural pressure were ever to equilibrate with atmospheric pressure

Answer 41

the transmural pressure would be abolished, meaning the lungs and thorax would assume their own inherent dimensions

Question 42

Pneumothorax

Answer 42

Air in chest

Question 43

Atelectasis

Answer 43

The lungs collapse to their unstretched size with no force present to stretch the lungs

Question 44

Traumatic pneumothorax

Answer 44

A puncture in the chest wall that permits air from the atmosphere to flow down pressure gradient and enter the pleural cavity abolishing the transmural pressure gradient

Question 45

Spontaneous pneumothorax

Answer 45

Hole in lung will permit air to move down pressure gradient and enter the pleural cavity from the lungs, abolishing the transmural pressure gradient