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What is the total adult lung volume?

3.5-8.5L

1

What is the hilum?

root of the lungs

2

What is the difference between visceral pleura and parietal pleura?

visceral adheres to the lungs, pleural lines thoracic cavity

3

What is the main muscle of inspiration?

diaphragm. 80% of inspiration, controlled by the medulla via the phrenic nerve.

4

Where does the phrenic nerve exit?

C3, 4, 5

5

Describe the mechanical process of inspiration.

diaphragm contracts and flattens, pulls down the parietal pleura which decreases pressure and draws air into lungs. 80% of the work. the remaining 20% is done by accessory muscles such as external intercostals, actively moving rib cage up and out

6

Describe the process of expiration.

Not a passive process diaphragm relaxes, elastic recoil of the lungs, chest wall, and abdominal structures compress the lungs, exhalation longer than inspiration intercostals assist with inward movement of the ribs

7

What are the accessory muscles?

Scalene from neck to first two ribs, Sternoclediomastoid raises the sternum, and pectoral is major and minor

8

What are the conducting airways?

nasal cavity, nasopharynx, oropharynx (soft palate to hyoid), laryngopharynx

9

Characteristics of the trachea

smooth muscles, 11cm long, c shaped cartilagenous rings

10

Characteristics of the carina

Tracheal bifurcation site, right main stem bronchus, important anatomical landmark 2-3 cm above carina for ett placement

11

Characteristics of alveoli

primary site of gas exchange

12

Type 1 alveolar epithelial cells

90% functioning alveoli, gas exchange

13

type 2 alveolar epithelial cells

greater number vs type 1 cells, a supporting cell, produce , store and secrete surfactant

14

functions of surfactant

decrease surface tension, stabilizes alveoli, prevents collapse, increases lung compliance, eases WOB

15

What are the two vascular systems of the pulmonary alveoli.

pulmonary (pulmonary arteries, divides into right and left branches, receives venous blood from the right side of the heart) and bronchial( no gas exchange)

16

Bronchial circulation

functions to distribute blood to the airways, does not participate in gas exchange

17

Alveolar capillary membrane

5 layers thick
no air in the blood
no blood in the alveoli
diffusion of oxygen and carbon dioxide
Co2 is 20x faster than o2

18

What is the maximum peak pressure

35mmHg

19

The rate of diffusion is influenced by

thickness of the alveolar capillary membrane
surface area of the alveolar capillary membrane
diffusion coefficient of the gas

20

Why is CO2 faster than O2 to perfuse?

because it is more soluble

21

What can impair diffusion through AC membrane?

pulmonary edema, ARDS, pulmonary fibrosis Thickens alveolar membrane

22

Function of pulmonary lymphatic circulation

removal of foreign matter, cell debris, remove fluid to help keep alveoli clear, produce antibody and cell mediated immune response
eventually drains into the primary lymph nodes located at the hila

23

two forms of oxygen

bound to hemoglobin 97% oxyhemoglobin, 4 oxygen molecules, SaO2
plasma oxygen PaO2diffuses to the cellular level, which the stimulates haemoglobin to offload its oxygen.

24

What determines o2 delivery?

cardiac output 4-8l/min
hemoglobin concentration
oxygen binding capacity of the hemoglobin
am
ount of oxygen int he blood SaO2

25

how much oxygen is extracted every minute?

25% arterial oxygen every minute

26

what changes hemoglobin binding capacity

hypoxemia, altered rbc morphology

27

describe the relationship between extraction an consumption

once maximum extraction is reached, further increase in demand or decrease in supply leads to hypoxia
then anerobic metabolism and lactic acidosis

28

what are the three forms of CO2 in the blood

plasma 10%
hemoglobin 30%
bicarbonate 60% can accept or reject components to maintain acid base balance

29

What is the v in the vq balance

ventilation
movement of air into and out of alveolus
normal alveolar ventilation 4L/min