Respiration

Question 1

Describe the 7 functions of the respiratory system

Answer 1

a. Provide body with oxygen:
b. Eliminate carbon dioxide from body:
c. Regulate hydrogen ion concentration in blood (pH):
d. Facilitate speech:
e. Provide a defense against microbes:
f. Influence chemical messengers in blood:
g. Trap and dissolve small blood clots:

Question 2

What is the use of providing oxygen to the body?

Answer 2

To make ATP (most critical function)

Question 3

Describe elimination of CO2 from the body as a function of resp system

Answer 3

CO2 is a by-product of cellular respiration, must be eliminated because when combined with H2O, creates carbonic acid which dissociates to HCO3- and H+ which can acidify body

Question 4

Describe the function of pH regulation by the resp system

Answer 4

helps eliminate H+ from other sources in conjunction with kidney

Question 5

Describe the function of facilitating speech by the resp system

Answer 5

larynx positioned at top of trachea, air exchange used to drive speech, function in exhalation

Question 6

Describe the function of providing defense against microbes by the resp system

Answer 6

epithelial secretions- secrete antibacterial factors and mucous (epithelial layers), lymphoid tissue (in mucosa, resident lymphocytes), reflexes- coughing and sneezing

Question 7

Describe the function of influencing chemical messengers in the blood by the resp system

Answer 7

convert ATI to ATII via ACE, ATII aldosterone secretion; inactivates hormones and cytokines (PGs)- clearance site for small molecules

Question 8

Describe the function of trapping and dissolving blood clots by the resp system

Answer 8

Venules in lungs good at clearing blood clots because a lot of plasmin, slow blood flow time to break down clots

Question 9

List the structures associated with the conducting zone

Answer 9

nose, mouth , pharynx, larynx, trachea, bronchii, bronchioles, terminal bronchioles

Question 10

Describe the basic functions of the structures of the conducting zone

Answer 10

• -no gas exchange, air moving by bulk flow- mechanical pressure gradient,
• -trachea and bronchi include cartilaginous rings and mucous glands- holds tube open skeletal structure, smooth muscle associated that can manipulate diameter

Question 11

List the structures associated with the respiratory zone

Answer 11

respiratory bronchioles, alveolar ducts, alveoli

Question 12

Describe the basic functions of the structures of the respiratory zone

Answer 12

• -gas exchange occurs because walls are thin enough for diffusion to occur,
• -smooth muscles in bronchioles regulate airflow, high SA,
• -highly vascularized- lots of gas exchange, blood flow, and pressure low due to branching,
• -low flow rate=lots of time for gas exchange

Question 13

Describe the properties of alveoli that increase respiratory surface area and enhance gas exchange.

Answer 13

a. Branching is important for respiratory function- 1 tube→ 8 million tubes; 300,000 alveoli per lung
b. Increased SA, lots of epithelium with blood around it where gas can exchange

Question 14

List the 3 types of cells found in an alveolus

Answer 14

1. Type I
2. Type II
3. Macrophages

Question 15

What is the function of type I cells in the alveolus?

Answer 15

gas exchange, epithelial cells, most common, squamous pink cells

Question 16

What is the function of type II cells in the alveolus?

Answer 16

secrete surfactant- watery substance lining wall of alveoli, detergent like, keeps it slippery, decreases surface tension, allows them to be open with no air in them

Question 17

Describe the components of the alveolar-capillary interface (i.e., what does a molecule of gas pass through?).

Answer 17

O2 and CO2 must cross: layer of fluid in alveolus, alveolar epithelium and basal lamina, interstitial fluid, capillary basal lamina and endothelium

Question 18

What is the difference between bulk flow and diffusion of gases?

Answer 18

a. Bulk flow: mechanical pressure gradient, no diffusion of gases
b. Diffusion of gases: where gas exchange occurs, CO2 and O2 exchange

Question 19

What is the relationship of the lung to the pleural sac (which contains intrapleural fluid) to the thoracic cage.

Answer 19

a. Pleural sacs surround lungs, 2 sacs (right and left), completely surround lungs, has inner and outer layer, air tight
b. 2 layers to pleural sac:
i. Parietal (outer)- attached to thoracic wall and diaphragm
ii. Visceral (inner) attached to lung
c. Intrapleural fluid fills sac (10-20um thick)
i. Lubricates surfaces: reduces friction during respiration
ii. Subject to pressure changes when thoracic cage expands or contracts- dictates expansion of lung

Question 20

8. Describe the mathematical relationship between airflow, a pressure difference, and resistance to flow

Answer 20

F=delta P/R

i. Delta P is gas pressure in alveoli minus gas pressure in atmosphere: P alv-Patm
ii. F= air flow
iii. R= resistance to flow

Question 21

Describe relationship of Palv to air movement in lungs

Answer 21

air moves into and out of the lungs because Palv is alternately less than and greater than atmospheric pressure
a. If PalvPatm, air flows out of lung- positive # for delta P, pushes air out

Question 22

What causes Palv to change (according to boyles law)?

Answer 22

P atm- constant because of change in lung volume due to change in thoracic cavity volume

Question 23

Describe atmospheric pressure in respiration

Answer 23

Atmospheric: pressure that the atmosphere puts on things in it, constant

Question 24

Describe alveolar pressure in respiration

Answer 24

Alveolar: pressure generated by air in alveolus

Question 25

Describe intrapleural pressure in respiration

Answer 25

Intrapleural: how much P on fluid/gasses in intrapleural fluid

Question 26

Describe transpulmonary pressure in respiration

Answer 26

Transpulmonary: calculated as Palv-Pip= Ptp

Question 27

Explain why intrapleural pressure is always subatmospheric under normal conditions.

Answer 27

Because 2 opposing forces pulling on the fluid in the sac, making it sub atmospheric unless there is pneumothorax

Question 28

Describe what happens to Pip and PTP during a pneumothorax.

Answer 28

a. Pip= Patm because air comes in, Pip=0 | b. Ptp= 0-0=0→ lung collapses because pressures are the same, rib cage expands

Question 29

List the muscles of respiration and describe their roles during inspiration and expiration.

Answer 29

a. Inspiration: external intercostals, shoulder muscles, make chamber bigger b. Expiration: internal intercostals, abdominal muscles, compress thorax

Question 30

Describe the pressure and volume relationships between breaths during a single respiratory cycle (7 steps)

Answer 30

Between breaths: i. Patm is 0 by definition because no normal changes ii. Palv equal Patm between breaths because no air moves iii. Pip below atmosphere pressure -4mmHg iv. Ptp=Palv-Pip, lungs remain expanded, +4mmHg, don’t completely deflate some pressure holding it open v. Lungs tend to recoid inward- very stretchy/elastic tissue, pulling away from visceral pleura vi. Chest wall tends to recoil outward- being pushed in by Patm vii. Net result is Pip is always subatmospheric

Question 31

Describe the pressure and volume relationships during inspiration in a single respiratory cycle (5 steps)

Answer 31

b. Inspiration i. Diaphragm contracts- thorax expands because pulls dome down against abdominal organ, volume increase so pressure decreases ii. Pip becomes more negative (more subatmospheric), because increase volume so decrease pressure iii. Ptp increases iv. Lung volume increases because of muscle contraction v. Air flows in until Palv=Patm then air stops moving

Question 32

Describe the pressure and volume relationships during expiration in a single respiratory cycle (5 steps)

Answer 32

Expiration i. Diaphragm relaxes- thorax compresses, dome moves back up, decrease volume, increase pressure ii. Pip becomes less negative- still subatmospheric iii. Ptp decreases iv. Lung volume decreases v. Air flows out until Palv=Patm

Question 33

Define lung compliance and list the determinants of compliance.

Answer 33

a. Lung compliance = change in lung volume/ transpulmonary pressure i. C= delta V/ (Palv- Pip) b. How well does it respond to a change in pressure c. Compliant- expansion readily occurs with small change in pressure