Bio 360 Exam 4 review
GFR is the Glomerular Filtration Rate. What is this?
the volume of fluid that filters into the glomerular (Bowman's) capsule per time unit
Step 3. Gas transport
through blood to or from lungs
Bulk flow (KNOW THIS)
total pressure difference
Step 1. Ventilation
(breathing) airflow between lungs and atmosphere by bulk flow
What do you need to know about the vasopressin hormone?
- neurohormone released by the neurohypophysis -effect on the collecting ducts of nephrons: more H2O channels = aquaporins inserted into collecting duct cell walls -> increase H2O reabsorption by collecting ducts decrease urine production -stimulus for vasopression release: Increased osmolarity of plasma and decreased mean arterial blood pressure (MAP)
Roles of the vasa recta?
-A specialized capillary network fed by the efferent arteriole leaving the renal corpuscle. -parallel to the loop of Henle in juxtamedullary nephrons, deep into the medulla. -blood flows in the opposite direction of the filtrate in the loop of Henle.(THIS IS IN RED) -blood flow is slow, giving solutes and H2O plenty of time for diffusion. Thereby blood cam mo ve through Vasa recta without disturbing the osmotic gradient need to deliver O2 and pick up CO2 from kidney cells
What does ALDO do when it arrives at nephrons? (YOU MUST KNOW THIS)
-ALDO is a steroid hormone that regulates gene expression -ALDO stimulates cells of the distal convoluted tubule and _______________ __________ to synthesize: ->Na+ channels (luminal membrane) ->Na+/K+ ATPases (basolateral membrane) resulting in more Na+ absorbed and H2O may follow Na+
Adult and fetal hemoglobins differ structurally
-Different global genes are expressed by different tissues than during human development. As a result, the structural composition of hemoglobin changes. -E.g the gamma (Y) global subunit of hemoglobin is produced by the liver, while B(beta) is produced by bone marrow.
What are the basic processes in nephrons?
-Filtration (this is in red) -Reabsorption (this is in red) Secretion
Glomerular filtration is regulated by functional microanatomy
-GFR regulation protects the nephrons from potential damage caused by over or underperfusion of the kidneys
What if surface tension is applied to alveoli?
-H2O molecules lining alveoli want to be close to each other and not in touch with alveolar air -favors collapse, and opposes the inflation of the alveoli
What happens to the bicarbonate, HCO3-?
-HCO3- is moved out of the RBC (this facilitates production of even more HCO3-) and transported in plasma to lungs
After going over the last slide So what happens now?
-Hb releases O2, and this O2 diffuses Fromm the RBC's into the plasma and into tissues... and so on -At PO2=40mmHg, the system reaches an equilibrium -About 25% of bound O2 has been unloaded (tissues at rest)
Changes in amount of O2 carried by Hb molecules=Changes in Hb molecules' saturation of O2 (in %)
-Hb that is NOT saturated with O2 is called DeoxyHb -Hb that is FULLY saturated with O2 is called OxyHb
Some thoughts about the "BIG" picture of renal physiology?
-If all capillaries were as permeable as in the kidneys, we'd blow up like balloons - if everything that entered renal tubules were excreted, we'd die quickly of dehydration and electrolyte imbalance
O2-Hb saturation curve: Hb saturation changes when RBC travel through capillary beds with different Po2 (YOU MUST KNOW THIS)
-In active tissues, Po2 is ,40 mmHg. Partial pressure gradient for O2 between blood and tissues is then larger (relative to lungs), than in resting tissues, so more O2 is delivered to active tissues. -Hb has different affinities to O2 depending on Po2. When Po2 is high, affinity is high (helps bind to O2 at lungs). When Po2 is low, affinity is low (helps "dumping" 2 at active tissues). -Bc of these mechanisms, the curve is not a straight line
How does increased aldosterone affect blood pressure in the renin-angiotensin system?
-Increased Na+ and H2O reabsorption -Increased blood volume -Blood pressure increases until it returns to normal
How do kidneys produce concentrated urine when vasopressin levels are increased?
-Kidneys have an osmotic gradient in the renal medulla, set up by the loop of henle -The high concentrations of solutes in the medulla allows for very efficient reabsorption of H2O if aquaporins are inserted into collecting duct walls.
Gas exchange occurs by simple diffusion. In alveoli, where do O2 and CO2 diffuse?
-O2 diffuses from alveolar air into the capillary bed -CO2 diffuses from the capillary bed into the alveolar air
Gas exchange occurs by simple diffusion. In tissues, where do O2 and CO2 diffuse?
-O2 diffuses from capillary blood into cells -CO2 diffuses from cells into the bloodstream
Blood carries much more O2 from lungs than one would predict based on the gas' solubility in plasma
-Only about 1.5% of the total O2 in a volume of oxygenated blood is dissolved in the blood plasma - The remaining 98.5% of the O2 present in oxygenated blood NOT dissolved in the blood plasma is bound to the protein hemoglobin inside red blood cells. (THIS IS IN RED) -RBC are produced by stem cells in bone marrow. mature RBC have large surface area and no nuclei
Loop of Henle
-maximum excretion with minimum water loss -length of loop of heel is related to the environment that the animal lives in -a longer loop will conserve more water, so animals in drier environments have longer loops
How is NA+ reabsorbed in the PCT?
-Primary active transport -Driven by Na+/K+ ATPases Sodium-potassium ATPases are found in basolateral-not luminal-membranes of epithelial cells -this "pumping" of Na+ increases the osmotic pressure in the intersitial fluid surrounding tubule, compared to the lumen and epithelial cells of the tubule -H2O follows Na+ out of lumen and into intersitial fluid
How do we move HCO3- out of RBC?
-RBC exchange HCO3- for Cl- ions by using an anion exchanger protein in the cell membrane called Band 3 -this is called the "chloride shift"
How are other solutes reabsorbed?
-Simple diffusion: H2O leaves the tubule with Na+, increasing the concentration of the remaining solutes in the tubule -Secondary active transport: amino acids move by Na+/amino acid cotransporter -Charge gradient: Na+/K+ ATPases create charge gradient so Cl- and HCO3- follow Na+ out of lumen
Why is alveolar PO2 (and PCO2) and the partial pressure gradient between alveoli and blood plasma important? (YOU MUST UNDERSTAND THIS)
-The partial pressures of alveolar air determine the PO2 and PCO2 of the arterial blood your body receives through the systemic blood circuit. -By the time blood leaves the lungs, the partial pressure gradients between alveoli and blood plasma are zeroed out, so the PO2 and PCO2 of alveoli and capillaries are equal
What are the immediate effects of increased angiotensin II?
-Vasoconstriction of arterioles -Stimulation of the adrenal cortex to increase ALDO
We normally have compliant lungs that remain inflated during ventilation. Now what?
-airflow (F) occurs from a region of higher pressure (P) to a region of lower P -if there is a difference between Patm and Pa, then air moves. If there is no difference, no air moves. --> we typically don't change Patm to drive ventilation
ALDO
-aldosterone hormone -increases Na+ reabsorption, which can also increase H2O reabsorption.
3. Most CO2 is converted to HCO3-. How does most CO2 convert to HCO3-?
-around 70% of the CO2 that is picked up in tissues for carbonic acid(H2CO3) in RBC by reaction with H2O. This reaction is catalyzed by the enzyme carbonic anhydrase (found in RBC1!) -carbonic acid H2CO3 is unstable and rapidly dissociates into bicarbonate ion (HCO3-) and H+ inside the RBC (THIS IS IN RED)
Osmotic gradient in human renal medulla
-blood plasma and typical interstitial fluid around 300 mOsm -the solutions in the renal medulla are filtrate, blood plasma, and intersitial fluid
Vascular component:
-blood plasma leaves the glomerular capillary by bulk flow through pores -bulk flow is driven by the capillary hydrostatic pressure (blood pressure)
So how do we change Pa? (THIS IS IN RED)
-by changing the volume of the alveoli
Can we calculate the partial pressure of O2 in the AIR?
-composition for atmpsphere: ->79% N2 ->21% O2 ->trace CO2 & H2O vapor -PO2 = Total air pressure x concentration of O2 in the atmospheric air -PO2 = 760 mmHg x 0.21 =160 mmHg at sea level
Baroreceptor cells detect changes in MAP --> info to brain (THIS IS IN RED)
-decrease MAP is sensed, leads to -(cardiovascular response) -increased vasopressin release, leads to -decrease urine production, leads to ... more fluid available to assist cardiovascular system to increase MAP
What are the conditions associated with reduced perfusion to the kidneys?
-decreased renal blood flow with a decreased stretch of afferent arteriole (sensed by stretch-receptors on JGA cells) -decreased MAP (barpreceptors to CNS to autonomic NS) increased sympathetic inpput to JGA cells
What are the tubular components of nephrons?
-distal convoluted tubule -glomerular -proximal convoluted tubule -collecting duck -ascending limb loop of Henle -descending limb loop of Henle -ursine to ureter
What are the vascular components of nephrons?
-glomerulus -efferent arteriole -afferent arteriole -peritubular capillaries -branch of renal artery -branch of renal vein -vasa recta
Central osmoreceptor cells in the hypothalamus detect Na+ levels in cerebrospinal fluid (THIS IS IN RED)
-increase osmolarity detect, leads to - increases vasopressin release, leads to -decrease urine production, leads to ... fluid and electrolyte balance restored
As long as we reach about 96-100% O2 saturation of Hb at the lungs, Hb can deliver enough O2 to active tissues (THIS IS IN RED)
-look at the flat part of the curve, at the lungs -At Po2=70-100mmHg in lungs, variation in Po2 produces only small changes in % Hb saturation (we reach about 100% saturation, regardless). -call this Safety plateau
What are the difference between cortical nephrons and juxta-medullary nephrons?
-most (85%) are cortical nephrons specialized for reabsorption and secretion -->short loop of Henle, dense peritubular capillaries -remaining 15% are juxta-medullary nephrons critical for concentrating urine -->long loop of Henle, capillaries form vasa recta capillary loop
After filtering of plasma (minus proteins) into Bowman's capsule, where does most tubular reabsorption occur?
-most H2O and solutes are reabsorbed in the proximal convoluted tubule (PCT) -The filtrate enters the PCT with a solute concentration similar to the plasma (except for proteins). -Reabsorption in PCT: -> 65%: H2O and NaCl ->100%: glucose and amino acids Reabsorption in the PCT is NOT a regulated process (not tuned on/off by hormones)
Nephrons (normally) take care of fluid balance. Why is that so important?
-osmosis allow H2O to move through the membranes that separate the extracellular and intracellular fluid compartments -H2O moves when we have an osmotic pressure gradient across these membranes -H2O moves from the compartment with low osmotic pressure to the compartment with high osmotic pressure -osmotic pressure is determine by concentration -high solute concentration in a compartment = high pressure in that compartment = H2O moves to that compartment
Applying principles to the partial pressure of O2=PO2
-parietal pressure gradients are differences in partial pressures between locations ->ex: PO2 between the alveoli and the capillary blood -O2 will show a net movement from areas with high PO2 to areas with low PO2 -> O2 moves from the alveoli to the capillary blood
CO2+H2O<-->H+ +HCO3- (she barely went over this)
-reaction is reversible -enzyme catalyzes rx in both directions
The partial pressure gradient and physiology that facilitate gas movement between alveoli and capillaries.
-the moisture in the alveoli allows gasses to dissolve on the cell surface -huge total surface are of alveoli in touch with capillaries -minimal separation (0.5um) of air and blood across the respiratory membrane
How do the central chemoreceptors in the medulla work?
-the receptors monitor changes in [H+] in the cerebrospinal fluid (extracellular brain fluid, CSF) -some CO2 always diffuses from capillaries into CSF and reacts with H2O. There is no carbonic anhydrase in the CSF to speed up this reaction, but also no buffer capacity (no Hb that bind the H+), so even very small changes in CO2 concentration lead to changes in pH -CO2+H2O-->H2CO3-->HCO3-+H+ When [H+] increase, chemoreceptors communicate to respiratory control center to increase ventilation Ventilatory response-->HOMEOSTASIS
What is the difference between (total) pressure gradients (Delta P) and partial pressure gradients? (YOU MUST UNDERSTAND THIS)
-the total pressure P in a gas mixture is the sum of the partial pressures of each gas. a difference in (total) P between 2 locations (Delta P) results in (directional) bulk flow of the entire gas mixture down the P gradient. -in gas mixtures, each gas has its own pressure = partial pressure. A partial pressure gradient of a single gas occurs when
Nephrons are up to _____ mm wide.
0.15 mm
1. renal corpuscle is how wide ? (mm)
0.15 mm wide
You have about ___ mill nephrons in each kidney.
1 mill
What other factors keep lungs from collapsing? (THIS IS IN RED)
1) Ptrans 2) surfactant from type-|| cells -detergent-like substances made of phospholipids and protein -decrease surface tension -increase lung compliance compliance=stretchability -increase lung compliance = requires less "pressure" to inflate alveoli and increase lung size
It is a natural tendency for lungs to recoil and assume a smaller volume due to what two things? (THIS IS IN RED)
1) elasticity of lung tissue 2) surface tension in alveoli
Why is atmospheric and alveolar gas composition different?
1)Air is humidified in airways, which increases PH2O. 2)The alveolar air is only partly replaced with each breath. 3)O2 always diffuses from alveolar air into fluid. 4) CO2 always diffuses from pulmonary capillaries into the alveolar air. ALL OF THE ABOVE REDUCE PO2 because the fraction of the total gas that is O2 reduced compared to the concentration of H2O and CO2 molecules
What are the 4 anatomical units the respiratory system relies on?
1. Conduction System (airways) 2. Exchange Surface (alveoli) 3. Muscle "pump" 4. Heart and Blood Vessels
What are the basic steps in respiration? (THIS IS IN RED)
1. Ventilation 2. Gas exchange 3. Gas transport 4. Gas exchange
How many forms is CO2 transported in the blood and what are they?
3 forms 1. around 7% is dissolved in the plasma. This fraction determines the plasma Pco2 2. around 23% diffuses into RBS and binds to fee amino groups in hemoglobin CO2+HB-->HbCO2 (carbaminoHb) 3. around 70% is transported as bicarbonate ions (HCO3-) that are produced in RBC and dissolves in the plasmsa
At what PO2 (mmHg) does the system reach equilibrium (in the context of Hb unloading)?
40 mmHg
What is each cluster of alveoli is surrounded by?
A capillary network
What will a difference in partial pressure of a single gas between locations cause? (THIS IS WRITTEN IN RED!)
A net movement of that gas by random diffusion
Why is asthma treated with B2-adrenergic agonist? A) Binding of agonist to β2-adrenergic receptors on bronchiole smooth muscle causes bronchodilation and alleviates asthma attacks B) Binding of agonist to β2-adrenergic receptors on bronchiole smooth muscle causes bronchoconstriction and alleviates asthma attacks 3) Binding of agonist to β2-adrenergic receptors on the heart slows the heart rate and causes relaxation, which helps alleviate asthma attacks
A) Binding of agonist to β2-adrenergic receptors on bronchiole smooth muscle causes bronchodilation and alleviates asthma attacks
Several metabolic factors shift the O2-Hb dissociation curve to the right. What does this mean physiologically? Assume that you can fully saturate Hb with O2 at the lungs. A. An additional amount of O2 can dissociate from Hbat the tissues B. Hb will have higher affinity for O2 at low levels of PO2 C. Significantly lessO2 will bind to Hbat the lungs
A. An additional amount of O2 can dissociate from Hbat the tissues
Imagine that the blue barrier is removed. Predict the main(most dominant) pattern of movement of the gas molecules (look at iclicker picture) A. Gas molecules move toward left, primarily by bulk flow B. Gas molecules move toward right, primarily by bulk flow C. Gas molecules move toward left, primarily by diffusion D. Gas molecules move toward right, primarily by diffusion
A. Gas molecules move toward left, primarily by bulk flow
Below is a stylized drawing of a renal glomerulus (G) with itsafferent (aff) and efferent (eff) arterioles. The arrows show thedirection of blood flow, and the diameter of the arteriolesindicate vasoconstriction or -dilation. Assume that an equalamount of blood enters the glomerulus via the afferent arteriolein illustrations 1. and 2.Choose the correct alternative: Compared to illustration 1.,the glomerular filtration rate in 2. is... (look at the iclicker picture) A. Increased B. Decreased C. The same
A. Increased
This ultra-high resolution CT scan of a kidney has a pixel size of0.12-0.15 mm (resolution limit, Oct. 2022). How well would this can work as a template for 3D printing a functional kidney? A. It would make the 3D-printed organ look like a kidney from the outside, but the inside would not contain functional nephrons. B. It would enable us to 3D print kidneys with functional nephrons, and provide a supply of kidneys that can replace organ trade
A. It would make the 3D-printed organ look like a kidney from the outside, but the inside would not contain functional nephrons
What is the largest structure? A. Nephron B. A solute C. Bowman's capsule D. Glomerulus
A. Nephron
Increased angiotensin I is converted into increased angiotensin II in the lungs by _______.
ACE (angiotensin converting enzyme)
Blood is both a tissue and a fluid. It is the most commonly transplanted tissue, worldwide.
Blood transfusions are life-saving e.g after catastrophic blood loss, but transfusion therapy is also a HOT area of research and debate
KEY CONCEPT: (THIS IS IN RED)
ATP burned to drive Na+/K+ pumps in the basolateral membranes provides a driving force for all other membrane transport events in PCT.
Active transport of Na+ from the ascending limb _____________ the osmolarity of the interstitial fluid surrounding the loop.
Active transport of Na+ from the ascending limb increases the osmolarity of the interstitial fluid surrounding the loop.
Why does the vasa recta does not "suck" Na+ out of the interstitial fluid?
Active transport out of the tubule wins against diffusion of Na+ into the capillary.
During ventilation.... A. Air moves by bulk flow fromthe alveoli to the atmospherewhen PA < Patm B. Air moves by bulk from the atmosphere to the alveoli when PA < Patm C. Air moves from the alveoli tothe atmosphere primarily bysimple diffusion D. Air moves from regions withlower gas pressure to regionswith higher gas pressure
B. Air moves by bulk from the atmosphere to the alveoli when PA < Patm
What happens to O2 at tissues?
Arterial blood with PO2 around 100 mmHg arrives at tissues that have a PO2 around 40 mmHg (at rest) -Dissolved O2 diffuses out of plasma into tissues, and out of the RBC's into plasma and into tissues and.... -with all of this diffusion, the PO2 inside the RBC's drops
As blood and filtrate flow past each other in opposite directions, ________ has time to leave the vasa recta and _________ has time to be picked up.
As blood and filtrate flow past each other in opposite directions, Na+ has time to leave the vasa recta and H2O has time to be picked up.
At the descending vasa recta, H2O moves ______ by osmosis and Na+ moves ____ by diffusion.
At the descending vasa recta, H2O moves out by osmosis and Na+ moves in by diffusion.
The afferent arteriole of your nephrons become vasoconstricted.What happens to the blood pressure inside the glomerularcapillaries, and what happens to glomerular filtration rate, GFR?A. Blood pressure increases andGFR increases B. Blood pressure decreases andGFR decreases
B. Blood pressure decreases andGFR decreases
Predict the movement of H2O by osmosis through the cell membrane (blue). H2O molecules are not shown. Solutes are indicated by triangles. ( look at the iclicker picture) A. H2O moves into the intracellular compartment B. H2O moves into the extracellular compartment
B. H2O moves into theextracellular compartment
What is the renal response to vasopressin? A. Increased reabsorption of Na+ by incorporating Na-channels and Na+/K+ ATPase pumps into the walls of the distal convoluted tubule and collecting ducts B. Increased reabsorption of H2O by incorporating aquaporins into the walls of the collecting ducts
B. Increased reabsorption of H2O by incorporating aquaporins into the walls of the collecting ducts
How can you best describealdosterone (ALDO)? A. It is an enzyme B. It is a steroid hormone C. It is a cotransporter forNa+ and glucose
B. It is a steroid hormone
Predict the main pattern of movement of the red gas after the blue barrier is removed. ( look at iclicker picture) A. It moves toward left, primarily by bulk flow B. It moves toward right, primarily by diffusion C. It moves toward left, primarily by diffusion D. It moves toward right, primarily by bulk flow
B. It moves toward right,primarily by diffusion
You climb to the summit of Mount Everest without oxygen support. Your leg muscles produce a lot of CO2. Under these physiological conditions, Hb normally reduces its affinity to O2 at tissues (so your O2-Hb saturation curve shifts right). How would this potential right-shift affect O2 delivery to leg muscles near the summit of Mount Everest? A. Most likely, a right-shift of the saturation curve causes O2 delivery to increase considerably near the summit of Mount Everest B. Most likely, a right-shift of the saturation curve does not improve O2 delivery very much near the summit of Mount Everest
B. Most likely, a right-shift of the saturation curve does not improve O2delivery very much near the summit of Mount Everest
What happens when oxygen-poor blood reachesyour pulmonary capillaries? A. CO2 reacts with H2O toform HCO3-, and theHCO3- is secreted intothe lungs over therespiratory membrane B. Newly formed oxyHbreleases CO2 and H+because oxyHb haslower affinity to CO2 andH+ than deoxyHb
B. Newly formed oxyHbreleases CO2 and H+because oxyHb haslower affinity to CO2 andH+ than deoxyHb
Urine testing for pathologies measures protein. What conclusion can you draw from a finding of high levels? A. The filtration of blood is normal, but something interferes with the process of protein reabsorption in the kidneys B. Something is wrong with the process of filtration of blood in the kidneys
B. Something is wrong with the process of filtration of blood in the kidneys
When hemoglobin (Hb) becomes 100% saturated with O2 at the lungs, then the PO2 gradient between alveolar air and the capillary blood will zero out. What is true about O2 molecules in this "zeroed out" environment? A. The simple diffusion of O2 molecules between the alveoli and the blood stops. In other words, the O2 molecules stop crossing the respiratory membrane. B. The O2 molecules continue diffusing between the alveoli and the blood, but their random movement is about the same in both directions. In other words, the net diffusion of O2 stops
B. The O2 molecules continue diffusing between the alveoli and the blood, but their random movement is about the same in both directions. In other words, the net diffusion of O2 stops
You can't remember were you parked! It is 105 F in the parkinglot... Luckily, you have 1 gallon of water. But, after 20 minutesof walking, drinking and sweating, the osmolarity of your bloodplasma starts to drop. Which statement correctly describesa response of your nephrons, i.e., to a drop in osmolarity? A. The renal cortex releases aldosterone B. The juxtaglomerular apparatus (JGA) releases renin C. The renal medulla releases angiotensin I|
B. The juxtaglomerular apparatus (JGA) releases renin
This mechanism can partly explain how lungs remain inflated and don't (normally) collapse: A. the alveolar pressure is always higher than the atmospheric pressure B. surfactant reduces the surface tension in the fluid coating the inside of the alveoli C. the transpulmonary pressure(Ptrans) pushes the lungs away from the chest wall and the diaphragm
B. surfactant reduces the surface tension in the fluid coating the inside of the alveoli
What is the layer of the cell membrane that lies next to the surface of adjoining cells?
Basal lamina
Why is simple diffusion a highly efficient process in respiratory physiology?
Because of specialized interface of alveoli and capillaries and mechanisms that regulate partial pressure gradients of O2 and CO2.
What does the respiratory system also helps us regulate?
Blood pH homeostasis
How does the vasoconstriction of arterioles affect blood pressure in the renin-angiotensin system?
Blood pressure increases until it returns to normal
TEST OF LOGIC: Relative to the atmospheric pressure(Patm) the alveolar pressure (PA) is: A. Always positive B. Always negative C. Changes between positive and negative
C. Changes between positive and negative
Which one of the following molecules or ions does NOT generally bind to hemoglobin (Hb) inside red blood cells? A. H+ B. O2 C. HCO3- D. CO2
C. HCO3-
Which option A-D best describes the 4th anatomical unit that the respiratory system relies on (the unit "missing" from the former slide)? (look at the iclicker picture) A. The airways B. The diaphragm C. The heart and blood vessels D. The alveoli Hint: Study this simplified illustration
C. The heart and blood vessels
Jon Snow was a social outcast for most of his life. Suddenly, a friend reveals that Jon is a true king and dragon rider and that Jon is having sex with his aunt. This information, and the associated stress, cause Jon's MAP to spike. Which statement correctly describes Jon's renal response to this increased MAP? A. The proximal convoluted tubules of his nephrons increase their reabsorption of H2O B. The collecting ducts of his kidneys release vasopressin hormone C. The juxtaglomerular apparatus of his nephrons constricts the afferent arteriole
C. The juxtaglomerular apparatus of his nephrons constricts the afferent arteriole
Dr. Amdam is watching the last episode of The Last of Us, Season 1.She gets so caught up in the ending, she holds her breath for severalseconds. Which statement about her respiratory physiology, duringthese short moments of breath holding, is TRUE? A. blood stops moving through the capillariesof her lungs B. O2 keeps moving from her alveoli into hercapillary blood by bulk flow C. air pressure in her alveoli (PA) is equal tothe atmospheric air pressure (Patm)
C. air pressure in her alveoli (PA) is equal tothe atmospheric air pressure (Patm)
How can you best describe carbonic anhydrase? A. it is an acid produced by the reaction of CO2 with H2O B. it is a buffer for H+ in bloodplasma C. it is an enzyme found in the red blood cells
C. it is an enzyme found in the red blood cells
When cells produce ATP, what do they also make?
CO2
What happens after HCO3- arrives at the lungs?
CO2 in plasma diffuses into alveolar air and the Pco2 of plasma and RBC drops. The Po2 of plasma and RBC increase and Hb starts loading O2. These events favor the reverse reactions: -CO2+HB<--- HbCO2 (CO2 transported by Hb is repelled) -H+ +Hb<---- HHb (H+ transported by Hb is repelled) CO2 diffuses down its partial pressure gradient, out of the RBC, into the plasma, and into the alveoli, but H+ cannot leave the RCB ( the RBC is impermeable to H+). Now, HCO3- is moved back in to the RBC and Cl- is moved out to facilitate the reverse reaction The CO2 diffuses down its partial pressure gradient, out of the RBC, into plasma, and into alveoli
What is the sequence of events during inspiration?
Central NS signal The diaphragm contracts and flattens Thorax expands ---> via Ptrans---> stretches lungs Alveolar volume increases ---> PA becomes more subatmospheric Air moves down the pressure gradient from the atmosphere to alveoli
The partial pressure gradients of dissolved gases provide the driving force for gas exchange, but additional, specialized mechanisms are required for efficient gas transport. (THIS IS IN RED)
Challenges that these specialized mechanisms must overcome: 1) O2 is not very soluble in blood plasma - the O2 that dissolves in the blood plasma, and that creates the PO2 of the blood, only covers 10% of your cells respiratory needs 2) CO2 is very soluble in water-based solutions like blood plasma, but reacts with H2O to form acid
What are the two types of nephrons? (THIS IS IN RED)
Cortical nephrons and Juxta-medullary nephrons
Where is Hb saturation the highest and lowest?
Highest: Alveoli Lowest: Peripheral tissue
What conditions are associated with reduced body Na+
Decreased osmolality of filtrate sensed by osmoreceptors or the macula densa cells
What does the JGA detect decreased perfusion as?
Decreased stretch of the afferent arteriole
How can we expand lungs without strain on lung tissue?
Each lung is enclosed by a super-thin fluid filled sac -one lining of the sac is attached to lung: visceral pleura -the other lining of the sac is attached to chest wall and diaphragm: parietal pleura (THIS IS IN RED) -the fluid layer sandwiched between the two pleura "pulls" (gently sucks) the lungs toward the chest walls, preventing lung collapse, preventing friction
What is another way of thinking about Ptrans?
Envision you have: Water, gravity, and a hand ->Water- layer between two glass plates pulled on by hand increases and gravity decreases ->Gravity-mimics lungs' natural tendency to collapse ->A hand holding the top plate can hold & move the lower plate because of the water. This mimics how the chest wall can move the lungs because of the pleural fluid.
What suppresses the release of vasopressin by blocking electrical currents in the neurohypophysis.
Ethanol
When PA becomes higher than Patm, what occurs? (THIS IS IN RED)
Expiration
True or False The saturation curve "shape" does not differ between animals.
False. It does differ between animals.
Reabsorption (THIS IS IN RED)
Filtrate volume is reduced and the composition of the filtrate is altered in renal tubule -almost all H2O and solutes are reabsorbed -substances not reabsorbed are excreted as urine
What happens to most of the H+ produced from carbonic acid H2CO3 inside the RBC?
Hemoglobin saves the day! H+ binds to Hb in the RBC forming HHb (reduced hemoglobin) - once bound to Hb, H+ ions cannot influence pH -> deoxyHb acts as a buffer for H+ inside RBC -deoxyHb (at tissues) has higher affinity for H+ than oxyHb (at lungs)
What occurs in the tissues in the context of Hb saturation?
Hemoglobin unloading
Why do we need a respiratory system?
For delivery of O2 from air to tissue and for removal of CO2 from tissues to air
O2-Hb saturation curve differs between life stages
For mothers to deliver O2 to a fetus, its necessary for fetal hemoglobin to 'extract' O2 from the maternal oxygeneted hemoglobin across the placenta. This requires the that fetal hemoglobin has higher affinity to O2 than maternal (adult) hemoglobin
What is surface tension?
Force at air-water interface due to attraction of H2O molecules for each other
In what direction will a gas show a net movement by diffusion? (YOU MUST KNOW THIS)
From areas with a high partial pressure to areas with a low partial pressure -total pressure differences are not directly involved in this movement
After extreme H2O intake what can't even save you?
Healthy nephrons
An increase in exercise capacity increases what?
Heart, muscle function and Ventilation
What occurs in the alveoli in the context of Hb saturation?
Hemoglobin loading
Basics of Reabsorption
If a substance isn't reabsorbed, then its excreted as urine.
In the ascending vasa recta, H2O moves _____ by osmosis and Na+ moves ______ by diffusion.
In the ascending vasa recta, H2O moves in by osmosis and Na+ moves out by diffusion.
Renin and angiotensinogen combine to produce ___________ ____________ ___ when a decrease in blood volume/pressure as a consequence of dehydration is sensed.
Increased angiotensin I
Increased osmolarity in the tubule implies _______________ Na+ concentration, making transport of Na+ out of the tubule more ______________.
Increased osmolarity in the tubule implies increased Na+ concentration, making transport of Na+ out of the tubule more efficient.
What does the JGA detect increased perfusion as?
Increased stretch of the afferent arteriole
When the size of the alveoli decreases, PA____.
Increases
When PA becomes subatmospheric what occurs? (THIS IS IN RED)
Inspiration
Differences between inspiration and expiration?
Inspiration is an active process Quiet expiration is passive -just based on the elastic properties of lung and thorax
In the gas exchange between alveoli and capillaries, where does oxygen diffuses into?
Into red blood cells
In the gas exchange between alveoli and capillaries, where does carbon dioxide diffuse into?
Into the alveolus
During exercise, what happens to expiration?
It becomes active - expiratory muscles contract to further reduce the size of the thoracic cavity and lungs -this additional reduction in alveolar size creates a greater DeltaP between alveoli and the atmosphere -airflow from alveoli to air increases because Falpha Delta P/R(THIS IS IN RED)
JGA constricts the afferent arteriole in response to increased stretch, thereby protecting the nephron from overperfusion, e.g when ________ _____ ____ _____.
JGA constricts the afferent arteriole in response to increased stretch, thereby protecting the nephron from overperfusion, e.g when MAP is too high.
Where is JGA is found?
JGA is found where the distal convoluted tubule is 'sandwiched' between afferent and efferent arterioles
How can a nephron sense perfusion (blood flow) changes and alter its GFR?
Juxta-glomerular apparatus (JGA) -includes granular cells with stretch receptors, and Macula dense cells with osmoreceptors (for osmolality)
What does vasoconstriction of the efferent arteriole result in?
Less blood flow out of the nephron
What does vasoconstriction of the afferent arteriole result in?
Less blood flow to the nephron
How important is surfactant?
Lifesaving! -premature babies with respiratory distress syndrome (RDS) -lungs have reduced compliance and the babies cannot produce enough force to expand lungs
Fundamentals of filtering: Capillary=Glomerulus Tubule=Glomerular (Bowman's) capsule
Renal corpuscle (blood vessel + tubule)
Why do lungs need to be "sucked to chest wall by Ptrans to maintain alveolar inflation during ventilation?
Lungs don't want to be inflated. They want to collapse.
The Loop of Henle
Maximum excretion with minimum water loss
Na+ pumping also explains how glucose is reabsorbed
Na+ is pumped out of epithelial cell, Na+ concentration gradient factors Na+ influx from lumen into tubular epithelial cell -glucose hitches a ride with Na+ on cotransporters against its concentration gradient across the luminal membrane into the cell -this is secondary active transport that uses the energy from the Na+ gradient established by the Na+/K+ ATPases burning ATP.
Microscopic anatomy of kidney reveals the function anatomy of _____.
Nephrons
What is the functional unit of kidneys?
Nephrons
What is required by cells to produce ATP?
O2
Applying O2-Hb saturation curve to pulmonary capillaries
O2-poor blood from tissues with PO2 around 40 mmHg arrives at alveoli where the PO2 is around 100 mmHg -this gradient of PO2 drives O2 to diffuse across the respiratory membrane, into the plasma, and into the RBC's -The increasing PO2 inside the red blood cells favors the binding of O2 to Hb: (Hb+O2---->HbO2) -molecular mechanisms increase Hb's affinity to O2, we saturate Hb and get oxyHb -blood has close to 100% saturation when leaving alveoli
How many ways is O2 and CO2 transported? (YOU MUST KNOW THIS)
O2: 2 ways CO2: 3 ways
What does all the O2 that binds to Hb do to PO2 in blood? (YOU MUST UNDERSTAND THIS)
Only dissolved gas- NOT bound-contributes to the partial pressure of O2 in a liquid. -The PO2 gradient from alveoli to the RBC's is maintained until about 100% Hb saturation is reached. (THIS IS IN RED) -Only when Hb molecules saturate, PO2 in the RBC'S increase, putting a stop to net diffusion of O2 -Maintaining the driving force (the partial pressure gradient) during O2 loading results in quick, efficient loading at the lungs.
How are changes in plasma osmolarity and MAP detected for the release of vasopressin?
Osmoreceptors and baroreceptors
How is H2O reabsorbed in the PCT?
Osmosis H2O follows solutes during reabsorption, in this case Na+.
2. CO2 binds to Hb at tissues. How do we release it at lungs?
OxyHb has lower affinity for CO2 than deocyHb, so when Hb binds O2 at the lungs, the affinity of Hb for CO2 drops and CO2 is released. (remember, Hb has high affinity to O2 at lungs) -T(tight)state-stabilized by electrical interactions that attract CO2 -R(relaxed) state-electrical interactions break as O2 is bound, CO2 is "repelled"
The pressure, produced by the forces acting on the fluid, is _______.
P trans
By what pathways are H2O and solutes reabsorbed in PCT?
PCT is lined with a single layer of epithelial cells joined by tight junctions -Tight junctions prevent movement of solutes between cells. -Reabsorbed solutes MUST pass through epithelial cells, called transepithelial (or transcellular) transport -H2O moves both through cells and tight junctions by transcellular and paracellular (between cell) pathways. -epithelial cell layer luminal membrane faces the lumen of tubule; the basolateral membrane faces the outside of the tubule
What factor is Hb saturation primarily determined by? (THIS IS IN RED)
PO2
Atmospheric air (resting conditions at sea level)
PO2 =160 mmHg PCO2=0.2mmHg
What does the O2-Hb saturation/dissociation/binding curve show the relationships between?
PO2 and Hb saturation
Alveolar air (resting conditions at sea level)
PO2=104 mmHg PCO2=40 mmHg
Alveolar pressure (THIS IS IN RED)
Pa= the sum of pressures of all the gases in the alveoli
What provides the driving force for the exchange of individual gases across cell membranes? (THIS IS WRITTEN IN RED!)
Partial pressure gradients
Atmospheric pressure (THIS IS IN RED)
Patm= sum of pressures of all the gases in the atmosphere -760 mmHg at sea level
Partial pressure (of a single gas C, Px) (THIS IS IN RED)
Po2= pressure of O2 in a mixture of gases anywhere: in atmosphere, alveoli, wherever there are gases
Respiration can only continue if this ______ ______ is available unless you are a fetus.
Respiration can only continue if this exchange surface is available unless you are a fetus.
Transpulmonary pressure (THIS IS IN RED)
Ptrans= a constant, sub-atomospheric pressure that maintains alveolar inflation by 'sucking' lungs toward chest wall
Oxygen diffuses into ________.
Red blood cells
What is GFR determined by? (THIS IS IN RED)
Renal blood flow, blood pressure, filtration surface area, and filtration barrier permeability
What happens in tissues when they receive blood?
Same principles apply, only the direct of gas exchange is opposite to lungs. -O2 and CO2 diffuse down their partial pressure gradients ->O2 out of capillary blood -> CO2 into capillary blood By the time the blood leaves the capillary beds at tissues, the partial pressure gradients between blood and tissues are zeroed out. Systemic venous blood that returns to the heart has the same PO2 and PCO2 as tissues
What is gas exchange driven by?
Simple diffusion of the gasses
Solutes must move from the loop into the interstitial fluid, _________________ the osmolarity of the medulla.
Solutes must move from the loop into the interstitial fluid, increasing the osmolarity of the medulla.
Steps 2-4 of gas exchange include gas exchange at the ____________, _____________, and gas exchange at the interface between ________________.
Steps 2-4 of gas exchange include gas exchange at the Alveolar-capillary interface transport of gasses in blood, and gas exchange at the interface between capillaries and tissues
Hb saturation (in %)
The % of oxyHb in blood relative to the total population of Hb molecules
When was the connection between surfactant and respiratory distress syndrome discovered?
The 1950's
What is the difference between the atmospheric (Patm) and the alveolar pressure (Pa)?
The driving force of F, the DeltaP. -F alpha (Patm-PA)/R (THIS IS IN RED)
The first human trials with _____ surfactant was found in 1980.
The first human trials with synthetic surfactant was found in 1980.
The loops of Henle receives filtrate with a ______________ mOsm than the filtrate that leaves the loop.
The loops of Henle receives filtrate with a higher mOsm than the filtrate that leaves the loop.
The mOsm of the blood plasma is ______________ than the mOsm inside the renal medulla.
The mOsm of the blood plasma is lower than the mOsm inside the renal medulla.
What allows gases to dissolve on the cell surface?
The moisture in the alveoli
The ______ shift occurs in response to factors that signal increased metabolic activity: Increased temperature Reduced pH (more H+ bc more CO2) Increased Pco2
The right shift occurs in response to factors that signal increased metabolic activity: Increased temperature Reduced pH (more H+ bc more CO2) Increased Pco2
The solute concentrations at the beginning and end of the vasa recta are the ________.
The solute concentrations at the beginning and end of the vasa recta are the same. Vasa recta doesn't "take" solutes from the gradient
What hormone increases H2O reabsorption as the collecting duct passes through the adrenal medulla?
Vasopressin (Antidiuretic hormone/ ADH)
How do the mechanisms of gas exchange and transport inform the mechanisms of ventilation?
Ventilation (rate and depth of inspiration) is regulated by reflex action triggered by chemoreceptors = sensory neurons that detect chemical changes and translate these changes into different rates of action potentials (AP) 1) peripheral chemoreceptors in aorta and carotid bodies -monitor Po2 in arterial blood -signal to control center in the brainstem to regulate ventilation 2) central chemoreceptors in brainstem (medulla) -monitor Pco2 via [H+] (pH) -very sensitive regulator of ventilation
When the curve is shifted ______, Hb shows increased affinity to O2. Occurs when factors signal reduced metabolic activity: Reduced temperature Increased pH (less H+ bc less CO2) Reduced Pco2
When the curve is shifted left, Hb shows increased affinity to O2. Occurs when factors signal reduced metabolic activity: Reduced temperature Increased pH (less H+ bc less CO2) Reduced Pco2
When the curve is shifted right, Hb shows _____affinity for O2 at most levels of Po2 and more O2 is delivered to tissues under normal conditions.
When the curve is shifted right, Hb shows reduced affinity for O2 at most levels of Po2 and more O2 is delivered to tissues under normal conditions.
In gas mixtures, each gas has its own pressure = partial pressure. When does a partial pressure gradient of a single gas occur? (THIS IS WRITTEN IN RED!)
When there is a difference in the gas' partial pressure between locations.
Can your O2-Hb saturation curve shift?
YES
Is HCO3- useful in plasma?
Yes, HCO3- can act as a buffer for H+ in the plasma
Secretion
active transfer of specific substances from renal capillaries into tubule for excretion as urine
Podocytes
are cells of the glomerular capsule that wrap around the capillaries where renal filtration occurs.
Simple diffusion (KNOW THIS)
basic molecular movement
Step 2. Gas exchange
between air in lungs and blood in lung capillaries by simple diffusion
Step 4. Gas exchange
between tissue capillary blood and simple diffusion
Big picture on filtration ---> excretion
blood flow in renal arteries is >1L/min at rest (average person) -at kidneys >15% of the blood plasma is filtered out of capillaries - around 180 L of renal filtrate is formed each day -normally, only around 1.5 L of urine is formed each day
Filtration (THIS IS IN RED)
blood flow through specialized capillary, solvent (H2O) and solutes are filtered into renal tubule -in healthy kidneys, all solutes are filtered except proteins (note: blood cells are not solutes)
Nephrons=________ + _________.
blood vessels and tubules
How does Na+ leaves the ascending loop?
by active transport
How does H2O leaves the descending limb?
by osmosis
There are shortcuts (holes) for this oxygenated blood to largely ______ the lungs; from right to left atrium and from pulmonary artery to the aorta.
bypass
Renin (MEMORIZE)
catalyzes a hormone pathway that can constrict the efferent arteriole of the nephron ( renal perfusion increases ), and increases total blood volume and Na+ levels to help the low MAP(and the associated low renal perfusion) return to normal
What is hemoglobin?
composed of protein and pigment. O2 binds to Fe2+ ion in the pigment (heme) group -when O2 binds, Hb turns bright red due to a microscopic displacement of the Fe2+ ion -Each Hb molecule has 4 heme groups, each carrying one O2 molecule. -Each red blood cell has millions of Hb molecules, and each RBC can carry 1 billion O2 molecules on average. (THIS IS IN RED)
What can we excrete when vasopressin is present?
concentrated urine
When the size of the alveoli increases, PA______.
decreases
What can we excrete when vasopressin absent?
dilute urine -dfiltrate that exits the loop of hence and enters the distal tubule is hypoosmotic: 100 mOsm compared to 300 mOsm in plasma
What happens to PO2 in the alveoli?
drops?
What happens to PO2 in the atmosphere?
drops?
Tubular component:
glomerular (Bowman's) capsule can accommodate bulk flow through its permeable epithelium: podocyte cells with filtration slits
What is the reaction for the respiratory system? (THIS IS IN RED)
glucose + O2 ---> CO2 + H2O +ATP
R is negligible in what kind of airways?
healthy
Air flow (F) a region of_____ pressure (P) to ______ pressure (P)
higher to lower -F alpha DeltaP/R (THIS IS IN RED)
Gene mutations in a similar receptor in humans correlate with increase likelihood of what?
intercourse before age 15, and increases risk of divorce
What are the two components of nephrons?
intricate vascular and tubular
What happens to Osmolarity inside the tubule when H2O leaves the tubule by osmosis due to the high solute concentration in the interstitial fluid.
it increases
Kidneys receive blood flow from _________.
large renal arteries
Step 1: Ventilation
movement of air in and out of lungs by bulk flow
Since R is negligible in healthy airways, if there is a difference between Patm and PA, air _____________. If there's no difference, ________ moves.
moves; no air
Integration of respiratory and cardiovascular physiology. You know this: Did you always use your lungs for gas exchange? yes or no
no
What is vasopressin is molecularly similar to?
oxytocin- a hormone associated with romantic and motherly love
How does H+ feed directly into pH? (She barely went over this)
pH -log10[H+] (don't memorize for Exam) -Atrial blood pH around 7.45 -Venous blood pH around 7.35 -Production of H+ from CO2 and H2O is a major reason for regulating the CO2 levels in the blood
Vasopressin binding to V1 receptors in specific areas of the brain during sex facilitates what?
pair bonding
What if altitude increases?
partial pressure drops?
What do the surfactant and associated therapies do to the mortality rate of RDS by >90%?
reduced the rate
What enzyme does JGA release in response to reduced stretch of the arteriole, and also when receiving increased sympathetic signaling from the renal nerve when MAP is too low. (MEMORIZE)
renin (this is in red)
During fetal gas exchange, where does the oxygenated blood from placenta enter?
right atrium
Prefix "Peri" (THIS IS IN RED)
situated around
Prefix "Juxta" (THIS IS IN RED)
situated near, close
The bronchioles have layers of ______ muscle with ______ receptors.
smooth ; B2 -adrenergic
O2 pickup and CO2 release at lungs (create your own fill in the blank!) (YOU MUST KNOW THIS)
sorry I can't find one
What shape of the O2-Hb saturation curve communicates the high efficacy of O2 loading at the lungs, and high efficacy of O2 unloading at tissues?
the S-shape
Partial pressure (YOU MUST KNOW THIS)
the pressure of an individual gas in a mixture -e.g the partial pressure of O2 =PO2 (mmHg)
Step 1. Ventilation (applying pressure terms)
when air flows between lungs and atmosphere by bulk flow
Do humans have genetic adaptations to high altitudes?
yes?
