Respiratory Part 2 Flashcards
Why does acid base balance matter?
— Enzymes
— Proteins
— Ion solubility, i.e bone breakdown
What are the three major buffer types in the body?
What are their characteristics ?
- Plasma proteins: their acid and base groups dissociate
- Hemoglobin: has histidine residues. Binds H+ ions. More powerful that plasma proteins.
- Bicarbonate buffering system
Write the bicarbonate buffering equation — which is the weak acid and which is the weak base?
CO2 + H20 → H2CO3 → HCO3- + H+
Carbonic acid is the weak acid that acts as a buffer in blood, and its conjugate base is the bicarbonate ion
Respond to these pH questions
What is the definition of respiratory acidosis? PH of what?
What is the cause? 2
How do we compensate? 2
Retaining too much CO2
What is the cause of respiratory alkalosis ? Ph of what?
What are the respiratory-related causes? 2 not vomiting!
How do we compensate? 2
Metabolic acidosis:
What is it?
How is it caused? 2
What is the compensation? 3
What type of breathing?
Ventilation effects are quicker
Kidney effects are long term but they are slower
Metabolic alkalosis:
What is it?
What are the causes? 2
How do we compensate? 3
Acid base nomogram
The way I would read this is the body is always trying to maintain the pH between 7.35 and 7.45 by
— Adjusting the CO2 (increasing/decreasing VE) move red lines
— Adjusting bicarb levels (y axis)
— Retaining/excreting H+ (x axis on top)
Right side of the graph is partial pressure of CO2 and the value holds for the length of the red line
What are the 4 categories of hypoxia — describe them
Hypoxemia —
Anemic —
Ischemic —
Histotoxic —
Hypoxemia — arterial blood
Anemic — low hemoglobin
Ischemic — to a specific tissue
Histotoxic — cells can’t use O2 for some reason
Hypoxia due to high altitude
At altitude, ventilation increases because we have less O2 in our blood If we are ventilating more, we are blowing off more CO2 so the CO2 decreases (hypocapnia), this leads to less H+ ions which means an increase in pH
This is represented by a left shift of the curve which happens with decreased temperatures
— Decreased O2 saturation
— Decreased unloading at the tissues
— Low oxygen stimulates EPO to make more hematocrit
Hematocrit volume percentage of red blood cells in blood
Hypoxemia due to right > left shunting — what are the 4 congenital heart diseases that lead to this? Describe them
Hypoxia due to V/Q mismatch
Acid base balance and hypoxia recap — answer the following questions
Remember, when you’re moving from acute to chronic, you’re always moving close to a normal pH so you can describe H+ ion concentration accordingly
With alkalosis you will be using less bicarb as you move from acute to chronic
With acidosis you will be using more bicarb as you move from acute to chronic
Hyperpnea vs hyperventilation — what is the difference?
[short answer]
Walk through the regulation of respiration.
Voluntary control via?
Autonomic control via? (3 portions)
Captured in [short answer]
Chemoreceptors
[short answer] Describe the Type I Glomus Cell Activation
[short answer] What are the steps in medullary chemoreceptor activation ?
Non chemical reflexive actions on ventilation —
Slowly adapting receptors drive which reflex?
Rapidly adapting receptors responsive to what?
Slowly adapting:
Hering Breuer reflex is triggered to prevent the over-inflation of the lung. Once activated, they send action potentials through large myelinated fibers of the vagus nerve to the inspiratory area in the medulla
Non chemical reflexive actions on ventilation —
Ending of C-fibres:
— Where?
— Stimulated by?
— Cause what to happen?
Proprioceptors:
— What stimulates respiration?
Pulmonary C fibers are unmyelinated nerve fibers that originate peripherally in juxtacapillary (or J) receptors located in the pulmonary interstitium close to both alveoli and pulmonary capillaries
They may be also stimulated by hyperinflation of the lung as well as intravenous or intracardiac administration of chemicals such as capsaicin. The stimulation of the J-receptors causes a reflex increase in breathing rate
Discuss the difference between coughing and sneezing and yawning
diaphragm suddenly spasms
Exercise ventilation
What is the primary driver of VE?
Factors that affect VE
— Chemoceptors
— Psychological
— Proprioceptors
CO2 primary drive of ventilation — where does it come from?
— aerobic metabolism
— buffering
— anaerobic metabolism
Acute effects of exercise on ventilation
What is the O2 deficit? Which system is working in the first 2-3 minutes?
What is EPOC ?
O2 Deficit is the time between starting exercise and when you’re body begins to support by bringing more O2 to the tissues via aerobic metabolism. Before we use aerobic metabolism the body is using the creatinine phosphate system
EPOC the result of rising oxygen consumption after workouts to replenish the O2 stores
Where does the CO2 come from?
Ventilation threshold
Changes in ventilatory response with exercise
[short answer] Review the chloride shift
