Exam 2 Study guide

Question 1

Hypoxia

Answer 1

Decreased oxygen in the tissues (poor oxygenation in the tissues)

Question 2

Ischemia

Answer 2

Inadequate blood supply to an organ or part of the body

Question 3

Anoxia

Answer 3

Absence or deficiency of oxygen in reaching the tissues

Question 4

Hypoxemia

Answer 4

Decrease in oxygen in the blood concentations

Question 5

Anatomic dead space

Answer 5

Volume of the conducting airway (150 mL); Measured by Fowler’s Method

More info: Conducting airways constitute the anatomic dead space because they contain no alveoli and thus cannot participate in the gas exchange

Conducting airways

• Trachea
• Bronchi (main)
• Lobar bronchi
• Segmental bronchi
• bronchioles
• Terminal bronchioles (smallest airway without alveoli)

The branching tubes of the airways become narrower and shorter and more numerous as they penetrate deeper into the lungs

Question 6

Function of the conducting pathways

Answer 6

Their function is to lead inspired air to the gas exchange regions

Question 7

Alveolar dead space

Answer 7

Volume of gas that enters unperfused alveoli per breath (Ventilated but note perfused)

Alveolar dead space refers to alveoli containing gas but without blood flow in the surrounding capilaries (example: pulmonary embolus)

Question 8

Physiological dead space

Answer 8

Total wasted air in the lungs

The anatomic dead space + the alveolar dead space (Bohr equation permits this)

Question 9

Hysteresis

Answer 9

The curves which the lung follows during inflation and deflation are NOT the same

Question 10

Muscles that are involved with active expiration

Answer 10

Abdominal muscles:

Rectus abdominis

Internal and External oblique abdominis

Internal and external transversus abdomins

Internal intercotal muscles (assist in active expiration by pulling the ribs down)

*these muscles are also contract forcefully during coughing and defacation

Question 11

Muscles that are involved with inspiration

Answer 11

*****Diaphrahm**** (most important muscles for inspiration)

when diaphragm contracts, it depresses

External intercostal muscles (pulls ribs forward and upward)

Accessory muscles:

Scalene mussle and Sternocleidomastoid muscle (little in quiet activity, active in exercise)

Muscles of the alae nosi (flaring the nostrils)

Small muscles of the had and neck

Question 12

Paradoxical movement of the diaphragm

Answer 12

This is when the diaphragm is paralyzed and results in the diaphragm moving upward instead of downward during inspiration

Question 13

Pore of Kohn

Answer 13

The pore of kohn communicates with adjacent alveoli and helps to maintain the average pressure among the alveoli

(negative): the pore of kphn can also communicate and spread infection with other alveoli

It is thought to be the collateral ventilation of the lung

Question 14

Atelectasis

Answer 14

is a complete or partial collapse of the entire lung or area (lobe) of the lung secondary to a deficiency in surfactant. It occurs when the tiny air sacs (alveoli) within the lung become deflated or possibly filled with alveolar fluid. Atelectasis is one of the most common breathing (respiratory) complications after surgery.

Can cause a physiological shunt

Question 15

Physiological Shunt

Answer 15

When V/Q ratio is low (low ventilation, high perfusion), there is inadequate ventilation to provide oxygen needed to fully oxygenate the blood flowing through the alveolar capillaries

Physiological Shunt = the fraction of venous blood passing through capillaries that does not become oxygenated + 2% of blood in bronchial vessels

Question 16

Expiratory reserve volume

Answer 16

Volume that is expelled from the lungs during a maximal forced expiration that starts at the end of a normal tidal respiration

~ 1.5 Liters

Parameters are ~ 1.1-1.5L

Question 17

Residual volume (cammpt be calculates using a spirometer)

Answer 17

The remaing volume in the lungs following maximal expiration

represents the force generated by muscles of expiration and the inward elastic recoil of the lungs

**importan to prevent the lungs from collapsing

~ 1.5 L

Question 18

Inspiratory reserve volume

Answer 18

The volume that is inhaled into the lungs during a maximal forced inspiration that starts at the end of a normal tidal respiration

~ 2.5 L

Question 19

Tidal Volume

Answer 19

Normal breathing

The amount of air entering or leaving the nose or mouth per breath

(Normal quiet breathing + Eupnea)

~ 500 mL or 0.5L

Question 20

Vital Capacity

Answer 20

The exhaled volume by maximal expiration

~ 4.5 L

VC = VT (Tidal volume) + ERV (expiratory reserve volume) + IRV (inspiratory reserve volume)

Question 21

Total lung capacity (cannot be measures with spirometry)

Answer 21

Volume of air in lungs after a maximal inspiratory effort

Combination of all lung capacities

Question 22

Functional Residual capacity (cannot be measured using a spirometry)

Answer 22

Volume of gas inside the lungs after normal expiration

balance point between the inward pull of lungs and the outward spring of the the chest

~ 3 Liters

FRC = ERV (expiratory residual volume) + RV (residual volume)

Question 23

Inspiratory Capacity

Answer 23

Volume inhaled after maximal inspiratory effort that begins at the end of a normal tidal respiration

Question 24

How is Pulmonary Blood Flow measured

Answer 24

Fick Principle

Q = VO2 / CaO2-CvO2 or Vo2 = Q(CaO2-CvO2)

Question 25

Boyle’s Law

Answer 25

The pressure of a gas tends to increase as the volume of the container decreases

Question 26

Recruitment

Answer 26

As pressure rises capilaries begin to conduct blood and lower overall resistance. (During excersie or at high pressure demands, the the capillaries that were collapsed not doing any work, becomes recruited to work

Question 27

Distension

Answer 27

With increased pressure, individual capillary segments begin to widen. The increase in distension is due to the very thin membrane which separates the capillary from the alveolar space.

Question 28

The anatomoical layers that oxygen has to transverse through the blood gar barrier from the alveoli to RBC (Blood-gas barrier)

Answer 28

(Surfactant, Type 1 pneumocyte, Basement membrane, Capillary endotheilial cell)

or

surfactant, alveolar epithelium, epithelial basement membrane, interstitial space, capillary basement membrane, capillary endothelium

Question 29

Lung compliance

Answer 29

The change in volume / change in plueral pressure

Volume change per unit pressure change

The extent that the lungs will expand for each unit increase in transpulmonary pressure

Question 30

Factors that determines Lung Compliance

Answer 30

Surface tension of the lungs (Alveoli): the higher the surface tension, the lower the compliance

Elasticity (Elastic recoil of the lungs (alveoli): compliance is inversely proportion to the elastic recoil of the lungs.

Question 31

Pulmonary fibrosis

Answer 31

Thickening of lung tissue that will decrease lung compliance

Question 32

Surfactant

Answer 32

Produced by Type II pneumocytes and decrease surface tension, which increase lung compliance

Question 33

Compliance relationship to lung volume and pressure

Answer 33

C= (change in lung volume) / (change in pressure)

Lung is less compliant at the highest volumes (peaks) and lowest ones

Question 34

Saline filled lungs

Answer 34

Saline filled lungs are more compliant that (V/P is greater) that air filled and shows no critical opening pressures or hysteresis

Question 35

Obstructive lung disease

Answer 35

Diminished expiratory flows and increased lung volumes

Rlatively small changes during inspiration

Question 36

Upper airway obstuction

Answer 36

Blunting of peak expiratory and inspiratory flow

curves will be flatter rather than proceeding to peaks

total tidal volume may remain the same

Question 37

Restrictive lung disease

Answer 37

Smaller lung volume durinf each respiratory cycle because one cannot expand and recoil the lungs

Curve will not reach as large volumes as normal

Examples : pulmonary fibrosis

Question 38

Function of Central Chemoreceptors

Answer 38

Responds to an increase in H+ concentration and if increased stimulates ventilation or if decreased inhibits ventilation.

Question 39

Stretch receptors (slow adapting pulmonary stretch receptors)

Answer 39

Aka: Slow adapting pulmonary stretch receptors (in airway smooth muscle)

Responds to distension

Main reflex effect: Slowing of respiratory frequency due to increase expiratory time

Hering-Breur Inflation Reflex

Question 40

Irritant receptors (aka Rapidly adapting pulmonary stretch receptors)

Answer 40

Responds to cigarette smoke, noxious gases, inhaled dust, and cold air

Located in airway epithelial

Main reflex: bronchonnstriction and hyperpnea (plays a role in asthma)

Inhibition of this receptor will prevent the reflex of initiating a cough

Question 41

J receptors

Answer 41

endings of nonmyleitanted C fibers

responds quickly tp chemical injected into the pulmonary circulation

Main reflex: sensation of difficulty breathing

Associated with Left heart failure and Interstitial lung disease

Question 42

Bronchial C fibers

Answer 42

supplied by the bronchial circulationa and respond quickly to chemical injected into bronchial circulation

Main response: rapid shallow breathing, mucous secretion, bronchoconstriction

Cough stimulation for new smokers

(asthma related)

Question 43

Gamma system

Answer 43

Strectch receptors in muscle (example: airway obstruction)

Question 44

Joint receptors

Answer 44

Movement is sitmulus for ventilation

Increases repiration at the start of exertion abruptly

Question 45

Function of Peripheral Chemoreceptors

Answer 45

Respond to low arterial O2 (Below 60 mmHG) and an increase of elevated PCO2

Located in carotid bodies at the bifurcation of common carotid and aortic bodies

Question 46

What produces surfactant

Answer 46

Type II Pneumocytes

Question 47

Function of surfacant

Answer 47

To reduce surface tentsion of the alveoli to reduce chances of small alveoli collapsing