Lecture 1

Question 1

what does the respiratory system do? (6)

Answer 1

1) expands the thorax
2) produces automatic contraction and relaxation of respiratory muscles
3) produces airflow into and out of the lungs
4) allows gases to move across the alveolar capillary membrane
5) transports O2 and CO2 to and from the tissues
6) insures that blood flow to the entire lung is adequate

Question 2

path of air

Answer 2

muscles contract, incr in vol of thoracic cavity, decr intrathoracic pressure –>alveoli expands passively and decr pressure –>air flows from environment to alveoli
CONVECTION
then diffusion across membrane into blood

Question 3

what are the non-respiratory functions of the respiratory system?

Answer 3

1) regulation of blood pH
2) regulation of water loss from body gas
3) thermoregulation (heat loss from body gas)
4) speech, smell, innate immunity (macrophage resp), metabolism of vasoactive hormones

Question 4

what does the metabolic rate tell the lung?

Answer 4

the bodys metabolic rate determines how much o2 the lungs must deliver (VO2) and how much carbon dioxide the lungs must excrete (VCO2)

Question 5

what is a typical rate for oxygen uptake?

Answer 5

Vo2 at rest is ~ 250mL/min

during exercise is 2-4 L/min

Question 6

what is typical rate for co2 production?

Answer 6

at rest co2 production is 200mL/min

at max exercise co2 production is 2-4L.min

Question 7

pulmonary capillary blood flow and pulmonary blood flow rate

Answer 7

pulmonary capillary blood is 70mL

pulmonary blood flow is 5000mL/min

Question 8

avleolar gas volume in lungs
alveolar ventilation rate?
total ventilation rate?

Answer 8

alveolar gas is 3L
alveolar ventilation rate is 5.25L/min
total ventilation rate is 7.5L/min

Question 9

tidal volume and anatomic dead space volume

Answer 9

tidal volume is 500mL

anatomic dead space is 150mL

Question 10

chest wall is composed of

Answer 10

the chest wall is composed of the ribs,sternum, diaphgram and vertebral column (is mobile and elastic)
*ribs are covered with muscle and connective tissue

Question 11

outer surface of lung is

inside of chest wall is covered by

Answer 11

the outer surface of lung membrane is covered by visceral pleura
the inside of chest wall is covered by parietal lung–>visceral pleura–>parietal pleura–>ribs

Question 12

what determines the lung and chest wall expansion rate and how does it happen continually?

Answer 12

the lungs and chest wall expand with a magnitude and frequency that is determined by the lung ventilation rate (ventilation rate determined by the body’s metabolic rate)
the pleural membranes (visceral and parietal) allow the lungs to expand with minimal frisction and there is thin serous fluid that lubricate

Question 13

what is a normal transpulmonary pressure and how is it calculated?

Answer 13

transpulmonary pressure or pressure across the lung is 5cm of water or 5cm above atmospheric pressure,
Ptp = Pa - Pip (alveolar - intrapleural pressures)

Question 14

problem with pneumothorax and how to fix

Answer 14

alveolar pressure is 0 and intrapleural p is 0 so no transpulmonary pressure
fix with ventilator (positive pressure opens lungs so Pa is +5cm)
fix with vaccuum on chest wall to relieve surrounding pressure (Pip = -5m so Ptp=0–5=+5

Question 15

muscles of inspiration

Answer 15

external intercostal + diaphgram

during heavy breathing, sternonuceidomastoid muscles and scalene muscle are reruited

Question 16

muscles of expiration

Answer 16

muscles relax for quiet expiration

active respiration involves internal intercostal muscles, rectus abdominus, external olique

Question 17

cartilage found mostly in

Answer 17

trachea and bronchi

Question 18

ciliated epithelium is mostly found

Answer 18

in the trachea and bronchi and are sparse in bronchioles, terminal bronchioles and respiratory bronchioles

Question 19

goblet cells are mostly found

Answer 19

goblet cells are mostly found in trachea, bronchi and a little in bronchioles

Question 20

smooth muscle mostly found

Answer 20

SM mostly found in bronchioles

some in trachea and bronchi

Question 21

what types of epithelia are found in the lungs?

Answer 21

trachea + bronchi : pseudostratified columnar
bronchioles, terminal/respiratory bronchioles, alveolar ducts: p. columnar and squamous
alveolar sacs: squamous

Question 22

clara cells

Answer 22

secrete protective glycosaminoglycans

are more numerous as you move from large to small airways

Question 23

conducting zone

Answer 23

trachea–>terminal bronchiole

Question 24

respiratory zone

Answer 24

respiratory bronchiole–>alveolar sacs

Question 25

what is the role of airway smooth muscle

Answer 25

to adjust airway diameter
relaxation of SM results in bronchodilation
contraction results in bronchoconstriction
airway diameter controls airflow resistance and ventilation distribtution

Question 26

blood supply to lungs

Answer 26

deoxygenated blood from the right heart goes to alveoli
oxygenated blood from left heart goes to conducting airways
almost all blood returns to left heart via pulmonary veins (oxygenated)

Question 27

total ventilation rate

Answer 27

is frequency of breathing times tidal volume

6L/min is normal

Question 28

alveolar ventilation

Answer 28

aka effective ventilation
is equal to tidal volume - dead space *frequcency
represents the gas that reaches the alveoli that can participate in gas exchange

Question 29

anatomic dead space

Answer 29

represents volume from nose to terminal bronchiole (conducting airways)
represents airways that are ventilated but not perfused

Question 30

physiologic dead space

Answer 30

represents anatomic dead space + space occupied unperfused alveoli

Question 31

how can anatomic dead space be measured?

Answer 31

by Fowlers method where a subject inhales 100% oxygen and a nitrogen meter measure the concentration of nitrogen at the subjects lips as she exhales. dead space is measured as when volA=volB on the curve