Exam 3 Flashcards
What are the three major physiological processes of respiration?
1) Ventilation: air from outside body to inside body
2) Gas from the air in the lungs to the blood
3) Transport of gas from lung and blood to cells
How do gases move with respect to pressure?
Gas moves down the pressure gradient: High to low pressure
What is bulk flow?
Is when a bunch of gasses move down the pressure gradient together. This is how air is moveing during ventilation
What is Boyle’s law?
Pressure is inversely proportional to volume (when one increases the other decreases)
What is Dalton’s Law? What does it allow for?
The total pressure of a gas mixture is equal to the sum of the partial pressures of al the gases in the mixture.
Allows us to calculate the partial pressure of a gas if the total pressure is known and the percent of the gas.
What is the pressure and composition of air at sea level?
760mmHg. Mostly O2 & N + some argon, carbon dioxide, and water.
How does temperature and humidity affect the partial pressure of oxygen and carbon dioxide?
Increased humidity and temperature decreases the partial pressure of O2.
Increased humidity and temperature also decreases the partial pressure of CO2 but not as drastically as O2.
CO2 is more soluble in water than O2
What is Henry’s Law?
The amount of dissolved gas in a liquid is proportionate to the partial pressure of the gas in the air around the liquid.
What are the ventilation pressures?
Patm: atmospheric pressure
Palv: Alveolar pressure
Pip: Intraplural pressrue
What is Patm?
Atmospheric pressure, it is fixed (typically not changing) at about 760mmHg
What is Palv?
Alveolar Pressure, the pressure inside the alveoli that is variable.
If it is less than 760 air moves in and we inhale
If it is greater than 760 air moves out and we exhale
What causes the pressure change that allows for inspiration?
Diaphragm moves down and flattens
External intercostals (in between the ribs) lift the rib cage up and out
Volume of lungs increases decreasing the pressure causing air to go in
What causes the pressure change that allows for expiration?
Diaphragm moves up and curves
External intercostals relax and ribcage drops.
Volume of lungs decreases, pressure increases, and air goes out
What are the other muscles of ventilation?
Sternocleidomastoid and scalenes: forceful inspiration
Internal intercostals and abdominal muscles: forceful expiration “squeezing the thoracic cavity”
What is Pip?
Intrapleural pressure: the pressure of the fluid in the pleural cavity that is always negative pressure
What causes the negative pressure of the Pip?
The opposite pulling of the chest wall that wants to go out “spring” but is prevented by the muscles and the lungs that want to go in “balloon”
The negative pressure keeps the lungs moving with the chest wall “vacuume”
What causes the pressure of the Pip to not be negative?
Damage to the serous membrane causing the cavity to no longer be sealed causing pneumothorax: air in the intraplaural space and the lung collapses
What are the three factors affecting pulmonary ventilation?
Compliance, elastance and resistance.
What is compliance in ventilation?
Ability of the lung to stretch.
Higher compliance: stretches more easily
Lower compliance: stretches more difficulty
What is elastance in ventilation?
Ability of the lungs to recoil.
Higher elastance: high recoil- recoil easily
Lower elastance: low reoil- recoil harder
What is resistance in ventilation?
Flow of air through lung tubes
Higher resistance is due to less space in the lung tubes
What is Fibrosis and how does it affect ventilation?
Damage to lungs by particulates (physical damage) that causes scar tissue to form (CT, mostly collagen not the epithelial tissue that should be there)
Characterized by lower compliance and higher elasticity (it is hard to keep air in the lungs)
What is emphysema and how does it affect ventilation?
Alveoli deterioration due to genetics or toxins due to smoke inhalation.
Characterized by higher compliance and lower recoil. *high residule volume
What is asthma and how does it affect ventilation?
Swelling of lower air ways, increased mucus production, and contraction of smooth muscles. Characterized by higher resistance.
How does the partial pressure of oxygen and carbon dioxide change with ventilation of 760 mmHg dry air?
Ventilation: PO2 = 160, PCO2 = 0.25
Alveoli: PO2 = 100, PCO2 = 40
Arterial blood: PO2 = 100, PCO2 = 40
Cells: PO2 <= 40, PCO2 >= 46
Venous Blood: PO2 <= 40, PCO2 >= 46
What accounts for the drastic change in partial pressures of oxygen and carbon dioxide in the air and in the alveoli?
The residual volume. There is lots of leftover carbon dioxide in the lungs plus the air in the lungs is very humid the increase in water vapor decreases the partial pressure of oxygen.
What is the structure and function of hemoglobin?
Hb has four heme groups each with a iron ion at the center which is the spot for oxygen transport
There are about 250 million Hb molecules per erythrocyte.
What are the methods by which oxygen is transported in the blood?
Plasma: ~2%
Hb: ~98%
How is oxygen transported in the plasma?
Oxygen dissolves in the water of the plasma. This method is not very efficient or reliable
How is oxygen transported by hemoglobin?
Oxygen binds reversibly to Hb forming oxyhemoglobin (HbO2). When the oxygen detaches the Hb is deoxyhemoglobin (HHb or Hb).
How do we know the saturation of hemoglobin? What is saturation?
We can measure how much oxygen is bound to the Hb.
Saturation is the percentage of Hbs in RBC that are filled with Oxygen.
What determines the saturation of hemoglobin?
The affinity–the ability of Hb and oxygen to stay stuck together (higher more sticky)–of Hb for oxygen.
What affects affinity?
The partial pressure of oxygen, the temperature, the pH, and the amount of carbon dioxide.
They change the shape of the Hb.
What is the effect of the partial pressure of oxygen on hemoglobin saturation?
Arterial blood: PO2 = 100mmHg Hb sat = ~98%
(lots of Oxygen is saturating the Hb)
Venous blood:
@ rest PO2 = 40mmHg, Hb ~75%
exercise: PO2 = ~20mmHg Hb sat = ~30%
How much oxygen is dropped of at the tissues at rest? Why?
Only ~23% oxygen is dropped off at the cells to preserve venous reserve so that when you begin exercising you can give more oxygen to the cells that need it.
What is the oxygen saturation curved used for? What shifts occur?
To observe a change in saturation in different situations.
Leftward shift increases affinity increasing the saturation
Rightward shift decreases affinity decreasing the saturation
What is the affect of temperature on affinity and saturation?
Higher: decreased affinity - systemic tissues
Lower: Increased affinity - pulmonary tissues
What is the affect of pH on affinity and saturation?
Lower: (more H+) decreased affinity - systemic tissue
Higher: (less H+) increased affinity - Pulmonary tissues
What are the factors affecting affinity and saturation in systemic tissues?
These tissues are metabolically active so the temperature is increased, the pH is lower (more H+), and there is more carbon dioxide.
What is the affect of carbon dioxide on affinity and saturation?
High partial pressure carbon dioxide decreases the affinity -systemic tissue
Low partial pressure carbon dioxide increases the affinity - pulmonary tissue
Carbaminohemoglobin
What are the methods by which carbon dioxide is transported in the blood?
Plasma: ~7% (CO2 is more soluble in H2O than O2)
Hb: ~23% (carbaminohemoglobin)
HCO3: ~70% (bicarbonate)
How is bicarbonate made?
CO2 is converted to HCO3 in erythrocytes and then transported in the plasma.
The HCO3 reaction is catalyzed by carbonic anhydrase
CO2 + H2O + carbonic anhydrase =(rev) H2CO3 (carbonic acid) what reversibly converts to HCO3- and H+
What is the significance of the bicarbonate reaction process being reversible?
In the systemic capillaries the reaction shifts towards the carbonic acid because there is lots of Carbon Dioxide
In the pulmonary capillaries the reaction shifts towards the carbon dioxide because there is lots of carbonic acid
What does it mean that bicarbonate acts as a buffer?
In the blood the bicarbonate helps to regulate pH
What is the process to get carbon dioxide from the Krebs cycle to the air?
1) CO2 diffuses out of cells into systemic capillaries
2) Only 7% of the CO2 remains dissolved in plasma
3) Nearly a fourth of the CO2 binds to hemoglobin, forming carbaminohemoglobin
4) 70% of the CO2 load is converted to bicarbonate and H+ Hemoglobin buffers H+
5) HCO3- enters the plasma in exchange for Cl- (the chloride shift)
6) At the lungs, dissolved CO2 diffuses out of the plasma
7) By the law of mass action, CO2 unbinds from hemoglobin and diffuses out of the RBC
8) The carbonic acid reaction reverses, pulling HCO3- back into the RBC and converting it back to CO2.
What is the function of the urinary system?
Maintain chemical consistency (composition) of blood: Conserve nutrients (so they X go to urine), maintain appropriate ion and pH levels
Filter fluid from the blood: maintains blood volume (EPO), and pressure (Renin)
Hormone secretion
Excrete toxins, metabolic wastes (urea & ammonia), and excess water (too much RBC swell & rupture) ions and vitamins (not all vitamins as some must be metabolically altered b4 excretion via urine)
What are the organs of the urinary system?
Kidney (main functional structure, urine production)
Ureter (long muscular tubes)
Urinary bladder (storage pouch)
Urethra (one tube)
Where are the kidneys located and what is their appearance?
Partially protected by the floating ribs (11&12) located between T11 & L3 vertebrae. Right kidney is lower than the left due to the liver.
Size: ~bar of soap
Shape: Kidney bean
What are the gross anatomy structures of the kidneys?
Hilum, renal sinus, renal capsule, renal cortex, renal columns, renal medulla, renal pyramid, renal papilla, calyx, renal pelvis