Chapter 2 - Heart and Lung Flashcards
What membrane is attached to the lungs, keeping them inflated?
pleural membrane
How does blood pressure change, starting from the aorta?
It is highest in the aorta and continues to fall until it comes back to the heart from the vena cava. The right ventricle pumps blood with some pressure to the pulmonary circuit that again falls.
What is atherosclerosis?
damage to endothelial cells by pressure or abrasive substances
What three physiologic changes cause hemoglobin to release more O2 to the tissues at the same partial pressure as in the normal case? This shifts the oxygen saturation curve for hemoglobin to the right or left?
1) decrease of pH
2) increase in temperature
3) increase in 2,3-bisphosphoglycerate (2,3-BPG) (a byproduct of glycolysis)
Shifts to right
What measurement affects the rate of blood flow the most?
radius of vessels
What is one osmol?
one mole of a molecule that does not ionize in solution
In the red blood cells, CO2 reacts with H2O and the enzyme carbonic anhydrase to form what molecule?
carbonic acid (H2CO3)
When the diaphragm contracts, do you expire or inspire?
inspire
Equation: Poiseuille’s Law (Flow)
What is sea level atmospheric pressure?
760 mmHg
What converts fibrinogen to fibrin?
thrombin
How many heme prosthetic groups (each containing Fe2+) are in hemoglobin?
4
What is the major stimulus that causes a slower rate of respiration?
Stimulus: an increase in O2 concentration in the blood Recognized by chemoreceptors in aorta and arteries
From what pulmonary structure(s) does the blood immediately leave to enter the heart?
right and left pulmonary veins
In the diffusion equation, what does the minus sign represent?
diffusion from high to low concentration
Which side of the heart pumps blood to the lungs?
right side
What causes expiration?
relaxation of inspiration muscles: elastic tissue in thoracic cage returns to its normal length
How many O2 molecules can hemoglobin bind?
4
How does HCO3- diffuse into the lungs?
In the capillaries of the alveoli, HCO3- diffuses into red blood cells from the plasma and combines with H+ to form carbonic acid (H2CO3). Carbonic anhydrase converts H2CO3 to water and carbon dioxide, which diffuses into the lungs.
Define osmotic pressure (πosm)
The amount of pressure that stops osmosis
How does osmotic pressure change with the number of dissolved molecules?
As solute concentration increases, osmotic pressure increases.
What causes inspiration?
Muscle contraction: as your thoracic cage expands, it expands the lungs, creating a subatmospheric pressure in the alveoli, allowing gas to rush in.
70% of CO2 is carried in the blood plasma in what form?
bicarbonate (HCO3-)
What vitamin is necessary in the blood clotting cascade?
Vitamin K
The head of membrane phospholipids is of what charge?
negative
Which structures of the circulatory system regulate the flow of blood and offer the most resistance?
arterioles: they have strong muscular walls innervated by the SNS
How does viscosity affect the rate of blood flow?
The higher the viscosity, the slower the rate of flow.
In which direction do veins carry blood?
toward the heart
Gas exchange between capillaries and alveoli/cells is driven by what factor?
partial pressures
Into what systemic structure(s) does the blood immediately enter from the heart?
aorta
Into what pulmonary structure(s) does the blood immediately enter from the heart?
pulmonary artery
What is the molarity of water?
55.5 moles/liter