Physiology Ii : (Test 1) : Respiratory System 1 : Chapter 13

Front 1

What is the primary function of the respiratory system?

Back 1

To obtain oxygen for use by cells and eliminate CO2 produced by cells.

Front 2

Respiration involves two separate processes. List them.

Back 2

1. Internal (cellular) respiration

2. External respiration

Front 3

Give a general description of internal (cellular) respiration.

Back 3

1. Mitochondria metabolize foodstuffs

2. Usually involves the use of Oxygen

3. Results in the production of CO2 and H2O

Front 4

What is exchanged during external respiration?

Back 4

Exchange of gases between environment and cells.

Front 5

List 4 steps of external respiration.

Back 5

1. Ventilation or gas exchange between the atmosphere adn air sacs (alveoli) in lungs

2. Exchange of O2 and CO2 b/n air in alveoli and blood

3. Transport of O2 and CO2 b/n lungs and tissues

4. Exchange of O2 and CO2 b/n blood and tissues

(Steps 1 & 2 involve respiratory system)
(steps 3 & 4 depend upon circulatory system)

Front 6

List 7 NON-respiratory fns of the respiratory system.

Back 6

1. Route for H2O loss and heat elimination

2. Enhances venous return (respiratory pump)(inhalation, expiration)

3. Contributes to maintenance of normal acid-base balance

4. Enables vocalizations

5. Defends against inhaled foreign matter

6. Modifies, activates, and inactivates materials passing through the circulatory system.

7. Nose: organ for smell

Front 7

How does the respiratory system defend against inhaled foreign matter?

Back 7

Has cilia and mucus that act as physical barriers. Macrophages also reside in the lungs.

Front 8

What happens to prosataglandins in the lung?

Back 8

It is inactivated.

Front 9

What happens to angiotensin in the lung?

Back 9

Activated

Front 10

Describe the general structure of the lungs?

Back 10

Two, left and right, each with several lobes.

Front 11

List the 8 connecting air passages of the respiratory system?

Back 11

1. Nasal passage/oral cavity

2. Pharynx

3. Larynx

4. Trachea

5. Bronchi (2)

6. Bronchioles (32): Terminal bronchioles (60,000), respiratory bronchioles (500,000).

7. Alveolar ducts (500,000)

8. Alveolar sacs (8 million)

Front 12

The respiratory system and circulatory system is basically a series of what?

Back 12

A series of branching tubes.

Front 13

What are the sites of gas exchange?

Back 13

Alveoli

Front 14

How many alveoli are present?

Back 14

~300 million

Front 15

Other than a series of branching tube structures the respiratory system also has associated ? for movement.

Back 15

Muscles.

Front 16

The pharynx is aka what?

Back 16

Vocal cords

Front 17

Where are the cartilaginous rings seen? Why?

Back 17

Seen in the trachea to keep it open.

Front 18

The bronchioles are surrounded by what?

Back 18

Cartilage, smooth muscle

Front 19

The bronchioles are regulated by what?

Back 19

By autonomic innervation, also sensitive to hormones and local neurotransmitters to dilate or constrict bronchioles.

Front 20

The alveolar sac is very important to ? ? and is surround by ? ?.

Back 20

Important to gas exchange and surrounded by pulmonary capillaries.

Front 21

What is the purpose of the Pores of Kohn that are observed in the alveolus?

Back 21

So 1 alveolus is able to move gas to another collateral ventilation (side by side)

Front 22

Alveoli general structure?

Back 22

Thin-walled, inflatable sacs.

Front 23

What is the main function of the alveoli?

Back 23

Gas Exchange

Front 24

The alveoli is encircled by what?

Back 24

Pulmonary capillaries

Front 25

What is important for the great rate of gas exchange seen in the alveoli?

Back 25

The proximity to capillaries and tremendous surface area gives a great rate of gas exchange by DIFFUSION.

Front 26

What does diffusion in general depend upon?

Back 26

1. Thickness

2. Surface area

3. Differences in [conc]

4. Permeability

Front 27

Describe the walls of the alveoli?

Back 27

Single layer of flattened type I alveolar cells.

Alveolar epithelium also contains type II alveolar cells that secrete pulmonary surfactant that facilitates lung expansion and keeps them open.

Alveolar macrophages are also present (immune defense).

Front 28

What is Fick's Law?

Back 28

For diffusion


(^C)(p)(SA) / (MW)(^thickness)

Front 29

What lines the entire internal surface of an alveolus?

Back 29

Pulmonary surfactant.

Front 30

The alveolus has a single layer of what kind of cells?

Back 30

A single layer of epithelial cells.

Front 31

The lung tissue consists of what?

Back 31

A series of highly branced airways, alveoli, pulmonary blood vessels, and lots of elastic connective tissue. This is important for inhalation and exhalation.

Front 32

The muscle of the lungs is subject to what control?

Back 32

In the walls of arterioles and bronchioles, both are subject to the control of the ANS. Local chemical mediators and hormonal control. So different areas can be opening while others can be closing.

Front 33

What amount of the thoracic cavity is occupied by the lungs?

Back 33

Most of the volume of the thoracic cavity is occupied by the lungs.

Front 34

What protects the lungs?

Back 34

Outer chest wall. 12 pairs of curved ribs, which join the sternum and thoracic vertebrae. This protects all teh soft tissue in the thoracic cavity.

Front 35

What is the diaphragm?

Back 35

Skeletal muscle for breathing. Also separates the thoracic cavity from the abdominal cavity.

Front 36

What is the pleural sac?

Back 36

Separate each lung from the thoracic wall (chest wall).

Front 37

What is the pleural cavity?

Back 37

The inside of the pleural sac. Pleural surfaces secrete fluid into this cavity which prevents pain and allows for the expansion and closing of it.

Front 38

Describe the parietal and visceral pleura of the pleural sac.

Back 38

1. Parietal Pleura = outer membrane = attached to chest wall

2. Visceral pleura = inner membrane = attached to internal organs

Front 39

Respiratory pressures involves the exchange of what?

Back 39

The exchanging of gases with the environment.

Front 40

What is atmospheric (barometric) pressure?

Back 40

P produced by weight of the air on objects on the surface of earth.

760 mm of Hg at sea level.

Decreases with increasing altitude above sea level. (so decreased pressure with increased altitude)

Front 41

What is intra-alveolar pressure AKA? What is it?

Back 41

Intra-alveolar (intrapulmonary) pressure. Pressure in alveoli. It is variable, equilibriates with atmospheric pressure.

Front 42

What is intrapleural pressure aka? What is it?

Back 42

Aka intrathoracic pressue. Pressure in the pleural sac.

Front 43

What does the intrapleural/intrathoracic pressure average at rest?

Back 43

756 mm Hg at rest.

This is also written as -4.
This is because it is 4 units below 760 mmHg atmospheric pressure.

So there is essentially a slight vacuum compared to atmospheric pressure.

Lost during pneumothorax (air in pleural cavity)

Front 44

Quick review:
At REST:

Atmospheric pressure = ?

Lungs pressure = ?

Intrapleural Pressure = ?

Back 44

Atmospheric pressure = 760 mmHg

Lungs pressure = 760 mmHg

Intrapleural Pressure = 756 mmHg or -4 mmHg

Front 45

The lungs are normally ?, filling the ?.

Back 45

The lungs are normally stretched, filling thorax.

Front 46

The lungs are normally stretched, filling the thorax. This is due, in part, to what?

Back 46

Due, in part, to intrapleural fluid's cohesiveness. Stickiness pulls lung outwards.

Front 47

Describe the transmural pressure gradient across the LUNG WALL?

Back 47

The transmural pressure gradient across the lung wall. There is a net outward P differential b/n INTRA-ALVEOLAR P and INTRAPLEURAL P.


The gradient pushes the lungs outward when intra-alveolar pressure is greater than P outside alveolie (that is the intrapleural P). (also helping to keep lungs open)

Front 48

Describe the transmural pressure gradient across the THORACIC WALL?

Back 48

Net inward P differential b/n ATMOSPHERIC P and INTRAPLEURAL P.

Front 49

What would a lung puncture do?

Back 49

Interfere with pressure gradients. Pressures would become equal and pushing outward would fail.

Front 50

Changes in what produces air flow in and out of lungs?

Back 50

Changes in intra-alveolar pressure produce flow of air in and out of lungs.

Intra-alveolar pressure < atmospheric pressure = air enters lungs

Intra-alveolar pressure > atmospheric pressure = air exits lungs

Front 51

Intra-alveolar pressure changes according to what? Explain.

Back 51

Changes according to BOYLE's LAW: (P1)(V1) = (P2)(V2)

There is an inverse relationship between P exerted by a qty of gas and its V.

Increased V = decreased gas P

Front 52

The changes in the volume of respiratory structures is achieved by what?

Back 52

Muscles

Front 53

Inspiration involves what of the respiratory muscles?

Back 53

It is an AUTONOMIC response that involves the CONTRACTION of the respiratory muscles.

Front 54

What muscles are contracted during inspiration?

Back 54

The respiratory muscles:

Diaphragm (innervated with phrenic nerve)

External intercostal muscles (innervated by intercostal nerves)

Front 55

75% of the enlargement of the thoracic cavity during quiet respiration is due to what?

Back 55

Due to the contraction and flattening of the diaphragm.

Front 56

The expansion of the thoracic cavity does what to pressure?

Back 56

Expansion of the thoracic cavity decreases INTRAPLEURAL pressure (754 mm Hg0.

-Lungs drawn into area of lower pressure so they expand.

-Increase in lung volume lowers intra-alveolar P below atmospheric p

- P gradient : air enters lung

Front 57

Expiration is a ? process.

Back 57

This is a passive process. No contraction involved, just relaxation of inspiratory muscles.

Front 58

The relaxation of inspiratory muscles during expiration involves what?

Back 58

Diaphragm and muscles of chest wall, plus elastic recoil of the alveoli, decrease size of chest cavity.

Front 59

During expiration what happens to intrapleural p?

Back 59

Intrapleural p INCREASES. The lungs are compressed. Decreased lung volume so increased intra-alveolar P.

The increase is to a level ABOVE atmospheric P, so air is forced out...thus expiration.

Front 60

What is forced expiration?

Back 60

The contraction of expiratory muscles further increases P gradient between alveoli and atmosphere.

Front 61

The intrapleural p is always ? lung p.

Back 61

It is always less. (see 2nd slide on p. 12 of notes)