Respiratory Part 2, Phys Exam 3

What is the composition of air?

Nitrogen (78.6%)

Oxygen (20.9%)

H2O (0.5%)
Carbon dioxide (0.04%)

What is Daltons Law?

Total pressure= sum of partial pressure of air composition (Nitrogen, Oxygen, Cardbon dioxide, water)

At sea level, 1 atm of pressure is equal to what?

760 mmHg

Is alveolar pH2O higher in humidity or is inhaled air higher in humidty?

Aveolar pH2O is 10x higher than inhaled air

When freshly inspired air mixes with residual air, the oxygen is diluted, with what?

The oxygen is diluted and enriched with CO2

Oxygen mmHg is:

160 mmHg

O2 mmHg within the alveoli is:

104 mmHg

CO2 atm mmhg is:

0.3 mmHg

CO2 alveoli mmHg is:

40 mmHg

For oxygen to get into the blood, it must:

dissolve

For carbon dioxide to leave the blood it must pass the other way and:

dissolve

Where does alveolar gas exchange occur?

Across the respiratory membrane

The greater the PO2 in the alveolar air, the more the blood will do what?

The more O2 the blood will pick up

The loading and unloading of gases depends on how long the RBC stays in the alveolar capillaries, what is the minimum time required to reach equilibrium?

0.25 sec

At rest, the RBC spends how much time in the alveolar capillaries?

0.5 sec

During strenuous exercise, how long does the RBC stay in the alveolar capillaries?

0.3 sec

Is CO2 more soluble than O2?

yes, 20 X more soluble

What can affect gas exchange?

pressure gradient of gases

Membrane thickenss

Membrane surface area

Ventilation-perfusion coupling

In higher altitudes, what happens to the partial pressure?

partial pressure of all gases is lower

What is ventilation-perfusion coupling?

The relationship between ventilation and perfusion, represented by the ventilation-perfusion ration. Ventilation rate is the total gas volume that enters and leaves the alveoli in a given amount of time, commonly measured per minute

What is the ventilation-perfusiton ratio?

0.8 (4.2 L of air/5.5 L of blood)

What is gas transport?

The process of carrying gases from the alveoli to systemic tissues and vise versa

What is the funciton of hemoglobin?

O2 transport molecule

One Hgb or Hb molecule can have how many oxygen?

4 O2

What is oxyhemoglobin?

O2 bound to Hgb

What is deoxyhemoglobin?

Hgb with no O2 bound

If there is 100 percent oxygen saturation with hemoglobin, how many oxygen are attached to it?

4

If there is a 50% oxygen saturation with hemoglobin, how many oxygen are attached to it?

2

What is the carrying capacity of hemoglobin?

1.34 ml O2/gm Hb

What is the normal amount of hemoglobin per 100 ml of blood?

15 gm Hb/100 ml blood

(20 mL O2/100 ml blood)

What is considered an anemic amount of hemoglobin per 100 ml of blood?

10 gm Hb/100 ml blood

13 ml O2/100 ml blood

Why is the hemoglobin oxygen dissociation curve represented as an S-shaped curve?

Binind of the 1st O2 to Hgb makes it 200x easier for the 2nd O2 to bind to Hgb

If there is a shift to the RIGHT on the dissociation curve:

Occurs at the tissues

Favors the unloading (release of O2) to the tissues

CO2 in the blood will INCREASE

Affinity for O2 will decrease in the blood

If there is a shift to the left on the dissociation curve:

Occurs in the lungs

Favors the unloading of oxygen

Loss of CO2 at lungs, exhale it

Affinity for O2 increases, oxygenating the blood in the lungs

to get more O2 to the tissues, will blood flow increase or decrease?

increase

What percent of CO2 participates in gas exchange?

Only 7%, because only 7% of it is dissolved

Dissolved CO2 is 20x more soluble than what molecule?

Oxygen

How much dissolved CO2 is in the veins, arteries and transported blood?

2.7 ml/100 ml blood

2.4 ml/blood ml blood

0.3 ml/100 ml blood

What is carbonic anhydrase?

An enzyme that catalyses the reversible conversion of carbon dioxide and water, into bicarbonate and hydrogen ions

What factors adjust the metabolic needs?

CO2 levels (decrease in pH, promote unloading of O2 to tissues)

pH (increase in pH, promote unloading of CO2)

Temperature (exercise will increase body temp, promoting the unloading of O2)

Biphosphorgycerate (BPG, 2,3 DPG), levels elevated by fever, thyroid H, GH. PRODUCED BY RBC

What is the Bohr effect?

A shift to the right, occurring at the tissues and unloading of O2 to tissues

What factors favor the Bohr effect?

Increase in partial pressure

Increase in [H}, which will decrease pH

Increase in body temp

increase in 2,3 DPG

ALL INCREASING

What is the Haldane effect?

Shift to the left

OCCURS AT THE LUNGS

LOADING OF O2 IN THE LUNGS

What factors favor the Haldane effect?

Decrease in pCO2

Decrease in [H] (increase in pH)

Decrease in body temp

Decrease in 2,3 DPG

Where can CO be found?

found in smoke, wildfire, cigarettes

Why is CO dangerous?

Competes for binding sites on hemoglobin molecule

What is a carboxyhemoglobin?

CO binds to ferrous ion of hemoglobin

How is CO poisoning treated?

Hyperbaric chamber, forcefully remove CO molecule

What molecule irreversibly binds?

Nitric oxide

How is a breathing rhythm generated?

Increase in firing

Increase activity of phrenic and intercostal nerve

contract muscles

INHALE

What are the two respiratory nuclei?

Dorsal respiratory group (DRG)

Pontine respiratory group (PRG)

Where is the DRG located?

Medulla

What does the DRG regulate?

Rate and depth of breathing

Where is the PRG located?

Pons

What does the PRG regulate?

Regulate rhythem of PRG

The PRG adapts the breathing during what?

Sleep

Exercise

Vocalization

Emotional responses

What are 2 additional respiratory centers?

Phneumotaxic center (pons)

Apneustic (pons)

What does the pneumotaxic center modulate and what happens?

Limits the inhale, inhibiting DRG, resulting in shallow breaths

What does the apneustic center regulate?

Decrease the frequency of breaths

What are the 3 lung receptors?

Stretch receptors

Irritant receptors

J receptors

Where are stretch receptors located?

Smooth muscle of airway

What is the function of stretch receptors?

Activate vagus nerve in the PSNS (decrease inhale, inhibits overinflation)

Where are the irritant receptors located?

Nasal mucosa, upper airway

What is the function of irritant receptors?

Bronchonconstriction by irritation, leads to sneeze or cough. can be caused by pollens, smoke, etc

Where are J receptors located?

capillary wall

What does the J receptors lead to?

Tachypnea (rapid, shallow breaths)

pulmonary edema and respiratory diseases

What are 2 chemoreceptors that are related to respiration?

Central

Peripheral

Where are central chemoreceptors located?

Medulla (4th ventricle)

What are central chemoreceptors sensitive to?

partial pressure of CO2

What is the most sensitive receptor in the human body?

The central chemoreceptor

Where is the peripheral chemoreceptor located?

Aortic bodies and carotid bodies

What are peripheral chemoreceptors sensitive to?

pH

Why is the peripheral chemoreceptor not very sensitive?

It takes a large decrease in O2 for it to be activated

Breathing CO acutely will do what to respiration (increase, decrease, or no change)?

NO CHANGE

Chemoreceptors sense pCO2 and pO2, not CO. They do not sense what is bound to molecules, the chemoreceptors only care about what is dissolved

Voluntary control over breathing originates where?

Motor cortex of the frontal lobe (cerebrum)

The motor cortex of the frontal lobe will send impulses down the corticospinal tracts to the respiratory neurons in the spinal cord, this bypasses what?

the brainstem

Rate and depth of breathing adjust to maintain levels of:

pH (7.35-7.45)

pCO2 (40 mmHg)

pO2 (90-100 mmHg)

What is the most potent stimulus for breathing?

pCO2 > pH > O2

what is acidosis?

pH < 7.35

What is alkalosis?

pH > 7.45, decrease pCO2

What is hypocapnia?

pCO2 < 37 mmHg

What normally causes hypocapnia?

Alkalosis

What is hypercapnia?

pCO2 > 43 mmHg

What is the most common cause of hypercapnia?

Acidosius

What is hypoxia?

Decrease O2 tissues

What is hypoxemic hypoxia?

Decrease pO2 in arteries (blood)

What is ischemic hypoxia?

Inadequate circulation (block oxygen)

What is anemic hypoxia?

Decrease O2 carrying capacity or low RBCs

What is histoxic hypoxia?

Metabolic poisons, cyanide poisons

How can oxygen toxicity occur?

Pure O2 (25 atm or more)

If you breathe pure oxygen for more than a few hours, what occurs?

Generates free radicals and H2O2

Destroys enzymes

Damages nervous tissue

leads to seizures, coma, death

How can infants be treated if they are born prematurely (premature lungs, not enough surfactant)?

Hyperbaric oxygen, however it can cause retinal damage

What factors can affect gas exchange (3 things)?

thickness of membrane

Surface area of membrane of # of alveoli

Ventilation-pertrusion coupling

What are the 2 major COPD disorders?

Chronic bronchitis

Emphysema

What is chronic bronchitis?

Inflammation of bronchial mucosa

Goblet cells enlarged (increase in mucus)

Chronic cough

Dyspnea, hypoxia, coughing fits, cyanotic

What is emphysema?

Decrease in alveoli

Decrease in surface area for gas exchange

Collapse of alveoli or lungs

easy to get air in, hard to get out

Weakness of thoracic muscles

A lot of energy ot breath

What is cor pulmonale?

R heart failure, hypertrophy and potential failure of right heart due to obstruction of pulmonary circulation

What is pneumonia?

Increase fluid and RBC in alveoli

Increase in thickness of respiratory membrane

What is TB?

Increase in thickness of membrane

Increase mucus and bacteria

Wall off lesions, fibrotic tubercles

What is the most common lung cancer?

Squamous cell carcinoma