Respiratory + Cardiovascular System Flashcards
What is the reason for extensive branching in the lungs
Increases surface area for gas exchange
Why are alveolus covered in surfactant
Lowers the surface tension fo the alveoli and facilitates gas exchange
Reduced surface tension allows them to remain inflated when the lung is compressed during exhalation
What prevents lungs from collapsing, what causes them to collapse
Pressure differential between the intrapleural space and the lungs
When air enters the intrapleural space the lung collapses because the pressure inside increases
What is negative pressure breathing
When we inhale the diaphragm moves down and the volume of the thoracic cavity is increased causing a reduced pressure compared to the external environement so they fill with air
How is alveolar gas exchange considered passive diffusion
In the lungs the partial pressure of oxygen is higher than in the deoxygenated blood so O2 diffuses into the capillaries until equilibrium is reached
In the lungs the partial pressure of carbon dioxide is lower than that of deoxygenated blood so the CO2 diffuses into the alveoli
What are the 5 functions of the lungs
Gas exchange
Thermoregulation
Protection against disease and particulate matter
Acid base regulation
Be able to trace a simplified circulatory pathway in your head
Vena cava to right atrium through tricuspid valve to right ventricle Pulmonary artery to lung Pulmonary vein the left atrium Left atrium to left ventricle Aorta into the body
Systole vs diastole
Systole - ventricles contract
Diastole - ventricles relax
Difference between arteries, arterioles, and capillaries
Arteries move blood and are innervated by the SNS
Arteriolies have more smooth muscle and are most involved in regulating blood pressure
Capillaries have no smooth muscle but very large surface area used for nutrient and gas exchange
Explain microcirculation***
Along a capillary the osmotic pressure DOESNT CHANGE and the hydrostatic pressure DECREASES
At first hydrostatic pressure is greater and so the fluid flows out of the capillary into the interstitium
At then venule end hydrostatic pressure is less so there is a net flow of fluid back into the capillary
About 10% of fluid is lost to the interstitium which travels to the lymphatic system
How are veins and venules different from ateries and arterioles
Lumen is larger and less smooth muscle so less pressure
How does blood velocity change according to surface area
Decreases from arteries (smallest surface area) to capillaries (largest surface area)
Increases in veins
How does blood pressure change
Decreases from arteries to capillaries (larger surface area) then constant in the veins
How is oxygen transported
Hemoglobin which contains 4 heme groups that can bind to one molecule of oxygen
Binding of oxygen at the first heme group induces a conformational change which facilitates the binding of more oxygen at the other heme groups called cooperative binding
Difference between cooperative non cooperative and negative cooperativity
Positive - binding of ligand is enhanced if other ligands already present n >1
Noncooperative - only has one binding site n = 1
Negative cooperativity - binding of subsequent ligand occurs with less affinity n <1
What happens to the ph when lots of CO2 is present in the body
Decreases due to more hydrogen ions that are produced
How is carbon dioxide transported in the body
Carbon dioxide in the peripheral tissue diffuses into the erythrocyte to combine with water and form carbonic acid
Dissociates into bicarbonate ion and hydrogen ion
Bicarbonate goes to lungs
HCO3 reassociates with H in the erythrocyte to form carbonic acid and then CO2 and water
Basically goes from carbon dioxide to hydrogen and bicarbonate so ph decreases
Explain the Bohr effect
When high concentrations of CO2, H and HCO3 form
The H ion binds to hemoglobin releasing O2 in the peripheral tissue
The hemoglobinH picks up CO2
How does CO2 travel through the blood
Either as bicarbonate (80%) or bound to hemoglobin (20%) **
What would shift the hemoglobin dissociation curves for oxygen right (less bound oxygen)
Increased CO2 (want to get more O2 into tissues) Decreased pH Increased temp Exercise Peripheral tissues 2,3 DPG - increases at higher altitudes
What would cause a hemoglobin dissociation curve for oxygen to shift left (more bound oxygen)
Decreases CO2 Increased pH Decreased temp In the lungs Fetal hemoglobin has a higher affinity for oxygen Carbon monoxide
How if myoglobin different from hemoglobin
Single polypeptide chain with only one heme group so it cants participate in cooperative binding
So has a hyperbolic oxygen dissociation curve
Only found in muscle tissue
Describe the shape of hemoglobin oxygen dissociation curve vs myoglobin
Hemo = S shaped Mayo = hyperbolic
Describe passive vs active exhalation
Passive - relaxation of diaphragm is enough for lungs to contract and air to flow in
Active - intercostal muscles involved
How are the lungs involved in the innate immune system
Ciliated cells
Goblet cells secrete mucus
Antibiotic proteins called defensins are secreted
How is respiratory system part of thermoregulation
Capillary beds in nasal cavity and trachea can vasodilate when hot so more blood passes through and therefore more heat released
Think of a dog panting because they cant sweat
What happens if blood is alkalemic
Reducing the rate of respiration allow carbon dioxide to build up and re-acidify the blood
What are the 3 components of blood
Plasma - has as whole bunch of hit water proteins hormones etc
Buffy coat - contains white blood cells and platelet
Hematocrit - red blood cells
How does changing plasma volumes affect hydration and blood pressure
Increases plasma volume - high blood pressure
Low volume - dehydration
How is plasma volume regulated by the endocrine system
Aldosterone increase sodium reabsorption
ADH increases water reabsorption
Atrial natriuretic peptide decreases sodium reabsorption
Explain erythrocytes function, formation, structure
Carry oxygen to tissues and carbon dioxide to lungs
Created in bone marrow in response to erythropoietin
Lose their membrane bound organelles
What are the consequences of red blood cells losing organelles
They have anaerobic metabolism and only like 100 days
Have a bioconcave shape so they can travel more efficiently and it increases the surface area
Explain what the ABO blood type system demonstrates and how it effects blood donation
Think about what this means for who can donate to who
Co dominance
The blood type you have is what antigen you express so
Blood type A would have A antigens and B antibodies
O is the recessive phenotype and has no A or B antigens but has antibodies to both
Explain the Rh factor of blood
Relate it to a mother and fetus
Single antigen that is either present or it isn’t
If someone is + they can accept from anyone because they dont make antibodies against it
If someone is - they can donate to anyone but cant accept from Rh + because they will have antibodies to it
Mnemonic to remember the valves in the heart
LAB RAT
Left atrium bicuspid
Right atrium tricuspid
Function of arteries, veins, and capallaries *** this is an easy concept but counts for points on the mcat
Arteries move blood away from the heart ie. pulmonary artery deoxygenated blood
Veins move blood to the heart ie pulmonary vein oxygenated
Capillaries is where gas exchange takes place
Explain why arteries have thick walls and veins have thin
Arteries carry high pressure blood
Veins carry low pressure blood and require valves to go against gravity
What type of junctions are in cardiac muscle
Gap this allows the action potential to move from SA node throughout the heart
Using the modified pouiselles law to describe how radius affects pressure in the circulatory system
Resistance is inversely related with radius to the fourth power
As blood flows from arteries to arterioles to capillaries the TOTAL RADIUS increases and thus the resistance (pressure) drops dramatically
What do you mean the radius increases from arteries to arterioles!
An artery branches out into thousands of capillaries
The total cross sectional area increases dramatically looking at the system as a whole
How is the continuity equation a1v1=a2v2 used to predict blood flow
Does blood move faster in arteries or capillaries
Applied directly when considering an artery narrowed by plaque
But if comparing artery to capillary must consider all the capillaries fed by an artery
Thus blood flow slows down in capillaries allowing time for gas exchange
Compare pressure between arteries, veins etc
Aorta > arteries > arterioles > capillaries > venues > veins > vena cava
Can you use bernoullis law for blood
Only is question tells us blood is ideal or you have a good reason to neglect viscosity and friction
Describe the cooperative binding of hemoglobin**
When the first heme (of 4) in the hemoglobin molecule binds with oxygen it facilitates subsequent binding
Distinguish between the T and R form of hemoglobin
T - tense - has low affinity for oxygen
R - relaxed - high affinity for oxygen
Explains shifts in the oxygen hemoglobin dissociation curve and why they happen to a friend
See sheet
