What is aerobic metabolism?
Aerobic metabolism is to break down a molecule such as glucose through a series of reactions that produce energy within the cells in the presence of oxygen.
- Glucose crosses the cell membrane into the cytosol (fluid portion of the cell)
- Glucose is broken down into pyruvic acid molecules and a small amount of ATP via glycolysis
- Since O2 is available, the process continues inside the mitochondria, where the process releases a much larger amount of ATP
(Side note: heat, water, and carbon dioxide are all made by this process but no worries since all of this gets used up by the body)
What is anaerobic metabolism?
The breakdown of molecules in the cell without the presence of oxygen.
- Glucose crosses the cell membrane into the cytosol (fluid portion of the cell)
- Glucose is broken down into pyruvic acid molecules and a small amount of ATP via glycolysis
- Becuase there is no O2, the process cannot continue and the pyruvic acid becomes latic acid
The production of lactic acid is very bad because it produces an acidic enviroment which inactivates enzyme function, disturbs cell membranes and ultimately leads to so death. Because you need energy to do everything in the body. This inadequate amount of energy leads to an inadequate delivery of oxygen and glucose to cells and will result in very little energy production. Reduce cellular function and the possibility of cellular damage.
What is the sodium potassium pump?
Sodium is the primary extracellular ion. Is potassium is a primary intracellular ion. Sodium naturally wants to move into the cell and potassium naturally wants to move out of the cell because they want to move into a lower concentration gradient. So the sodium potassium pump requires energy to work in order to trade three sodiums out of the cell for 2 potassiums inside the cell. If we do not have energy then the sodium potassium pump cannot work and sodium will collect inside the cell and attract water which then the cells will swell and eventually rupture and die. Cell death.
What is the composition of ambient air at sea level?
-78% nitrogen
-21% oxygen
-0.9% argon
-0.03% carbon dioxide.
(Trace amounts of other gases)
What is the difference between FiO2 and FDO2?
FiO2 is the fraction of O2 inhaled. For example, you can use an NRM at 0.95 to deliver an oxygen concentration of 95%
*USED FOR PATIENTS WHO CAN BREATH ON THEIR OWN
FDO2 is the fraction of oxygen delivered. For example you can ventilate using a BVM at 15 liters per minute which is approximately 95-98% O2 concentration
*USED FOR PATIENTS WHO CAN NOTTTTTT BREATH ADEQUENTLY ON THEIR OWN
What is boyles law?
An increase in pressure (more positive) will decrease the volume of gas
A decrease in pressure (more negative) will increase the volume of gas
Describe how the process of ventilation works?
By contracting the diaphragm (does 60-70% of the work) and the external inner coastal muscles diaphragm moves slightly downward, while the ribs are lifted upward and out word. This causes the thorax to increase in size, creating a negative pressure. Normal pressure is 760 mmHg but immediately before inhaling you increase the size of the thorax and create a pressure of 758 mmHg. When you exhale, the diaphragm and external intercostal muscles relax, allowing the chest wall to move inward and downward. The size of the thorax decreases and so less gas leads to more pressure, 762 mmHg.
What is minute ventilation? (Also known as minute volume)
The amount of air moved in and out of the lungs in one minute.
You can figure out the minute ventilation by multiplying the tidal volume by the frequency of ventilation in one minute.
For example, an average sized adult has a tidal volume of 500 mL and breatws approximately 12 times per minute, therefore, their minute ventilation would be calulated at 6000 mL or 6L/minute
What is tidal volume?
The volume of air breathed in with each individual breath.
Important points to consider with minute ventilation.
- a decrease entitled volume decreases the minute ventilation
- a decrease in frequency of ventilation decreases the minute ventilation
- a decrease in minute ventilation reduces the amount of air available for gas exchange in the avioli.
- a decrease in minute ventilation can lead to cellular hypoxia
- to ensure adequate ventilation to patient must have both inadequate title volume and an adequate rate of ventilation.
Why is it that hypoxia can still happen in a patient with a high frequency of breaths per minute but a low title volume
There is a small amount of air actually getting to the alveoli for gas exchange.
What is alveolar ventilation?
The amount of air moved in and out of the alveoli in one minute.
The formula is (tidal volume - dead air space) x frequency of ventilations per minute
For example, (500 mL - 150 mL) x 12 = 4200 mL or 4.2L/minute alveolar ventilation
What is dead air space?
Anatomic areas in the respiratory tract where air collects during inhalation but there is no gas exchange. This can include the trachea, bronchi, and bronchioles.
What are important considerations with aveolar ventilations?
- the patient may begin to breathe faster to move more air in and out of the thorax. However, that does not mean he is getting more oxygen into his aveoli for gas exchange.
- the dead air spaces will fill first regardless of the volume of air breathed.
- to improve gas exchange in the patient with an inadequate title volume you must provide positive pressure ventilation to move more air into the aveoli.
-. you cannot improve the ventilation or reverse the cellular hypoxia, by simply pacing a patient with inadequate tidal volume on oxygen. - assessing the title volume is as important as assessing tthe ventilatory rate.
Here are a few things which can cause cellular hypoxia.
- a low tidal volume
- a ventilatory rate that is too slow
- a ventilatory rate that is too fast (the lungs aren’t getting full enough between breaths and this fast rate requires energy and causes an increase in muscular workload.) +40 is too fast for adults and for Pediatrics, its +60 breaths per min
- an increase in dead air space
What are chemoreceptors?
Specialize receptors that monitor the PH, carbon dioxide and oxygen levels in arterial blood.There are two groups of chemo receptors , the central and peripheral.
Central are located near the respiratory center in the medulla. *HYPERCARBIC DRIVE
Peripheral are located in the aortic arch and carotid bodies in the neck *HYPOXIC DRIVE
What is the following association between carbon dioxide and acid?
The greater the amount of carbon dioxide in the blood the greater the amount of acid
The lesser the amount of carbon dioxide in the blood the lesser the amount of acid
Summarize the response of ventilation to stimulation by the central chemical receptors from changes in carbon dioxide.
An increase in arterial carbon dioxide increases the number of hydrogen ion’s in the CSF stimulating an increase in the rate and depth of respiration to blow off more carbon dioxide.
A decrease in arterial carbon dioxide decreases the number of hydrogen ion’s in the CSF causing a decrease in the rate and depth of the respiration blow off less the carbon dioxide.
Summarize the activity of the peripheral chemoreceptors?
A significant decrease in the arterial oxygen content causes an increase in the rate and depth of respiration to increase the content of oxygen in the blood.
What are the three types of lung receptors. (These receptors provide impulses to regulate respiration)
Irritant receptors:. These receptors are found in the airway and are sensitive to irritating gasses, aerosols and particles. They stimulate a cough, bronchial construction and increase ventilatory rate.
Stretch receptors: these receptors are found in the smooth muscle of the airways and measure the size and volumes of lungs. They stimulate a decrease in the rate and volume of ventilation once stretched by high tidal volumes to protect the lungs from over-inflating.
J-receptors: these are
Found in the aveoli near the surrounding capillaries and are sensitive to increases in pressure in the capillary.One activated the j receptor stimulate rapid shallow ventilation.
Describe the two ways oxygen can be transported?
Approximately 1000 mL of oxygen is delivered to the cells every minute.Oxygen is transported by the blood in 2 ways, either dissolved in plasma (1.5-3%) or attached to hemoglobin (97-98.5%)
Describe how oxygen is transported by hemoglobin?
Hemoglobin has four iron sites for oxygen to bind to. Thus 1 hemoglobin molecule could carry up to 4 oxygen molecules. Once the oxygen molecule binds with hemoglobin , it is referred to as oxyhemoglobin and hemoglobin without oxygen is called deoxyhemoglobin.
Describe how the saturation of an oxygen molecule works.
Because there are four iron sites for the oxygen to go to each iron site is considered too saturate twenty five percent. 3 iron sites filled with oxygen means 75% saturation.
Describe how anemic patients do not possess the oxygen carrying capacity as normal people.
Even though the anemic patient can have a normal SP02 level, there is less hemoglobin in the blood which means less sites for the O2 to attach to. The cells will not be receiving the amount of occasion that they need metabolically.
