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
Inside the capillaries, which is greater: hydrostatic or osmotic pressure?
hydrostatic pressure
Many enzymes in the blood clotting cascade belong to what class?
serine proteases
What makes the “lub” sound during a heartbeat?
the closing of the atrioventricular valves
What property of arteries maintains the directional flow of blood?
elasticity maintains arterial pressure
What are the epithelial cells of the blood vessels called?
endothelial cells
How many subunits make up hemoglobin?
4
Where is the mitral valve?
between the left atrium and left ventricle
Where in the lungs does gas exchange occur?
alveoli
What is average/normal blood pressure?
120mmHg/80mmHg
What is the osmolarity of a 1M solution of sodium chloride?
2 osmols/liter (one from Na+, one from Cl-)
What is edema?
An excess of interstitial fluid because it cannot be reabsorbed by the lymphatic system.
How are varicose veins formed?
When the one-way valves are damaged, blood can flow backwards and build up pressure.
What is the diaphragm?
skeletal muscle and connective tissue separating the lungs from the abdomen
How much bound oxygen is typically released to the tissues from the blood?
25%
What specific molecule forms a blood clot?
fibrin
How does H2CO3 react in red blood cells??
It ionizes to form bicarbonate (HCO3-) and H+
Equation: relationship of O2 partial pressure in gas and liquid phases
(PO2)gas = (PO2)liquid
Which side of the heart pumps blood to the tissues of the body and back?
left side
From what systemic structure(s) does the blood immediately leave to enter the heart?
superior and inferior vena cava
Where is the tricuspid?
between the right atrium and right ventricle
What is meant by turbulent arterial flow?
The opening of the artery is narrow as a result of the pressure cuff, so blood has a difficult time flowing.
What is the major stimulus that causes inspiration muscles to contract and how is it recognized?
Stimulus: an increase in CO2 concentration in the blood Recognized by chemoreceptors in the brainstem
What and where is the pacemaker of the heart?
sinoatrial (SA) node, on the right atrium
Two ways baroreceptors negate the loss of arterial pressure:
They send impulses to the medulla, which activates the sympathetic nervous system. 1) The SNS releases norepinephrine at the SA node, which increases heart rate, contraction, and blood pressure 2) SNS will stimulate adrenal medulla to release epinephrine (adrenaline), which increases heart rate, contraction, and blood pressure.
Define diastole?
ventricular relaxation
How does vessel length affect the rate of blood flow?
The longer the vessel, the slower the rate of flow.
What is meant by laminar arterial flow?
The opening of the artery is normal, so blood can easily flow.
Define systole?
ventricular contraction
What is partial pressure of a gas?
concentration of that gas in a mixture of gases
How do metabolites affect circulation?
Upon diffusion to the arterioles of the tissues, smooth muscle dilates, allowing increased flow of blood to supply nutrients and oxygen, while carrying away waste.
Equation: Fick’s Law (net rate of diffusion)
J = - DA(ΔC/Δx)
J = mol/sec
D = diffusion coefficient
A = area in plane of interest (cm2)
ΔC = concentration gradient (mol/cm3)
x = distance (cm)
Define osmolarity
The concentration of solute particles in solution
Equation: cardiac output
Cardiac Output = Heart Rate x Stroke Volume
CO = liters/minute
HR = beats/minute
SV = liters/beat (out of ventricles)
What is the purpose of the lymphatic system?
It collects excess fluid that leaked into the interstitial space from the capillaries, filters it, and returns it to the circulatory system.
What is arteriosclerosis?
cholesterol builds up on lesions of damaged endothelial cells, causing plaque and hardened arteries
Where do electrical impulses go from the SA node?
They travel over the atria and spread to the atrioventricular (AV) node, to the bundle of His, which spreads over the ventricles.
Define hydrostatic pressure (PH2O)
Fluid pressure at equilibrium that arises from the force of gravity
How much oxygen in the alveoli capillaries is typically bound?
98%
What is asthma?
an allergic hypersensitivity to airborne antigens that cause mast cells to released substances that cause bronchiole smooth muscle to constrict
What is oxygen’s transport protein in the blood?
hemoglobin
Which structures in the circulatory system contain one-way valves?
veins
ventricle ► atrium or atrium ► ventricle?
atrium ► ventricle
What makes the “dub” sound during a heartbeat?
the closing of the pulmonary and aortic valves
Where is the lymphatic system?
parallel to the circulatory system
What is the purpose of the chordae tendineae?
They hold the atrioventricular valves in place so they do not invert.
Which structures in the circulatory system carry 50% of the blood volume?
veins
Which structures in the circulatory system cary 16-20% of the blood volume?
aorta and arteries
What causes hemophelia?
lack of Factor VIIIa that helps make Factor Xa
What is the purpose of cilia in the respiratory tract?
They beat toward the pharynx, moving mucus and foreing particles upward.
