Physiology Final Exam

You are monitoring a patient whose severe pneumonia damaged her pleural membranes. Howdoes damage to the pleural membranes interfere with respiration? Be specific.

The main issue here is that this will disrupt the negative pressure gradient that is normally present between the alveoli and the pleura (2 pts), which is necessary to keep the lungs associated with the chest wall and thus prevents the lungs from collapsing (2 pts). In this situation, the pressure will equalize across the pleural membrane, and the loss of the pressure gradient will cause the lung(s) to collapse—it would only be one lung collapsing unless the damage is present in both lungs. It is far more difficult to breathe with a collapsed lung (2 pts)—requires much more expansion of the thoracic cavity to alter the pressure enough to create the negative pressure gradient between the atmosphere and the lung(s).

Airway resistance influences airflow rates. F= ΔP/R, where F=airflow, ΔP=the atmospheric intra-alveolar pressure gradient, R=resistance of airways (determined by airway radius, r; where R is inversely proportional to r4). Fill out the following sentences:

as delta p increases, f increases as radius decreases, r increases, and f decreases

tubular secretion

selectively moves substances from blood to filtrate in renal tubules and collecting ducts the transfer of materials from peritubular capillaries to the renal tubular lumen; it is the opposite process of reabsorption. this secretion is caused mainly by active transport and passive diffusion. usually only a few substances are secreted and are typically waster products.

what would be the osmolarity of a 1 L solution containing 1 M NaCl and 1 M CaCl2 and 1 M sucrose?

6 osmol/L

Recently, doctors have made many more diagnoses of autoimmune diseases, including lupus, multiple sclerosis, and rheumatoid arthritis. Why are these diseases called "autoimmune diseases"? In your answer, be sure to describe the importance of T cells and antibodies in these diseases.

Autoimmune diseases occur when the immune system fails to "tolerate" self-antigens expressed within particular tissues, typically because B and/or T cells that recognize self-antigens were not properly destroyed during their development. Because these "auto-reactive" B and T cells recognize and are activated by self-antigens, antibodies recognize self-antigens and activate complement, killing associated cells, and cytotoxic T cells directly kill cells expressing these self-antigens. Because the immune system is essentially attacking itself, these diseases are referred to as autoimmune diseases.

Explain the concept of external respiration in the context of pressure gradients. Your response should include (but probably not be limited to) a graphic showing changes in intra-alveolar pressure through the respiration cycle.

The pressure gradient is the difference between the atmospheric pressure and the intra-alveolar pressureandis positive during inspiration. Because air will travel along the gradient, air will be coming into the lungs. The opposite is true during expiration. The pressure is higher inside the lungs than outside and the air will travel to the exterior environment.

Could the two antibodies shown here be produced by the same B cell? Why or why not?

These antibodies are not being produced by the same B cell—within each naïve B cell, there is a random rearrangement of DNA that yields specific antibody variable regions, which are the regions that bind antigen. Because in this case, the two antibodies shown are binding different regions on the same antigen, they cannot have the same variable regions, which means that they did not come from the same genomic rearrangement or the same B cell.

types of transport in different parts of the nephron

active transport: in the kidneys at the reabsorption stage in the nephrons capillaries that surround the tubules carry the waster substances that the body needs from the waster that can be reused. osmosis: if there is an imbalance of solutes (more solute in fluid than blood), water goes to where there is higher concentration of solute which is lower concentration of water. can get osmosis without a transporter, but having a transport protein like aquaporin is useful because it increases the rate of osmosis. any osmosis happening without the aquaporins is very slow potassium channel is facilitated diffusion sodium glucose symporter: diffusion of sodium into the cell is providing energy needed to move glucose into the cell up its gradient anti-porter of sodium and protons sodium moving into the cell is powering the movement of protons out of the cell carbonic anhydrase inside that is breaking apart, generating carbonic acid which dissociates so you can pump out the protons, reabsorb the bicarbonate ions, bicarbonate movement down its gradient into the blood is causing movement of sodium up its gradient (moving sodium out of cell) glucose facilitated diffusion protein primary active transport na/k pump collecting duct reabsorbing sodium

what happens to cells in the ecf if osmolarity increases?

blood is hypertonic cells will shrink lower volume water inside cell chemical gradients would be changed which affects secondary active transport: diffusion is always going down a gradient and releases energy as it does so, the stronger the gradient of that driving ion, the more transport you can get against its gradient ex. in both the kidney and the digestive tracts there are both glucose sodium symporters (same direction across a membrane) movement of sodium down gradient is propelling the movement of glucose up its gradient. higher osmolarity means there is more sodium, and with more sodium then there is a stronger gradient to get more glucose transport. might seem like a good thing with the glucose reabsorption, but not all secondary active transport is going to positively promote from this.

why do humans need hydrochloric acid in our stomachs?

get rid of bacteria and viruses stuff in water in food digests nutrients (proteins) pepsinogen (needs hydrochloric acid to be present)

how could you treat a patient who was exposed to co?

give them pure oxygen blood transfusion hyperbarot chamber higher concentration of oxygen and increase pressure

the venous blood displays a reduced o2 affinity compared to arterial blood b/c its:

hemoglobin saturation is lower co2 partial pressure is higher h+ concentration is higher

how would inhibition of phagocytosis affect immune responses?

inhibit exogenous antigen processing prevent activation of cd4+ T cells

the first line of defense against microorganisms that infect the body is referred to as

innate immunity

how would changes in volume during inhalation and exhalation affect pressure?

intralaveolar pressure and intrapleural pressure: inhaling these numbers decrease (always have lower pressure in pleura than alveoli) exhaling: increases

co2 is more easily transferred into water across respiratory membranes compared to o2 because co2

is more soluble in water

what organ is responsible for urine production

kidney

in the mammalian alveoli, the partial pressure of o2 is _______ that of atmospheric air and the co2 partial pressure is ______ that of atmospheric air

lower than; higher than

a direct effect of the active transport of nacl in the ascending limb of the loop of henle is that the fluid in the ________ becomes ________

lumen; hyposmotic

in oxygen transport to the mitochondria, diffusion occurs from the:

lungs to the red blood cells red blood cells to the mitochondria

what is the source of antigens presented by mhc i? mhc ii?

mhc i: antigens are coming from inside the cell mhc ii: extracellular spaces

are these antigens likely to be self antigens, foreign antigens, or both?

mhc i: self they should not be able to recognize self antigens, but if its infected with a virus that make it very different from a regular mhc i, the t cells go kill target cells. mhc ii: outside the cell via phagocytosis, so they are foreign however some things are phagocytose by self

what is the pathway of o2 from the outside to the tissues that need o2?

nose -> pharynx -> larynx -> trachea -> bronchus -> bronchioles -> alveoli -> capillaries -> venules -> pulmonary vein -> left atrium -> left ventricle -> aorta -> arterioles -> capillaries -> tissues that need o2

effector cells that secrete antibodies are known as

plasma cells

what happens to the arterial blood pressure if ecf volume decreases

pressure will decrease affects cells, transport reactions, action potentials, change blood pressure.

when is the innate immune system particularly important

primary response

tubular reabsorption

process of reclaiming water and solutes from the tubular fluid and returning them to the blood the second time they have been absorbed; the first being when they were absorbed into the bloodstream from the digestive tract after a meal.

which of the following wouldnot be found in the urine produced by healthy kidneys?

proteins

glomerulonephritis is an inflammation of the glomeruli of the kidney. symptoms of glomerulonephritis include pink or cola-colored urine from red blood cells in the urine and foamy urine due to excess protein. what function of the kidney is impaired or damaged by glomerulonephritis?

proteins and rbc's getting though more stuff is getting through not regulated things problem with filtration when blood vessels are inflamed, there are much larger gaps than before and more things can pass through

The x-ray below (from Wikipedia) shows the lungs of a person suffering from pneumothorax. Use a diagram to explain how a pneumothorax leads to a collapsed lung. Make sure to mention the barometric pressure, the pressure within the pleural cavity (or intrapleural pressure), and the pressure within the lungs (also called intra-alveolar pressure).

puncturing the pleura, which means that the pleura is at the same pressure as the atmosphere. damage in the pleura coming from the outside in, youre going to equilibrate it with the barometric pressure. if its coming from the inside, an infection or inflammation damaged the pleura, equalize the pressure in the opposite direction. either case the key is at some point during the exhalation process there is going to be no pressure difference. without this difference, then there is no pulling of the lungs next to the chest wall, which means that youre going to collapse (not going to be able to hold lung close to the chest wall)

adaptive immune system

response time: days specificity: highly diverse; adapts to improve during the course of immune response response to repeat infection: more rapid and effective with each subsequent exposure major components: t and b lymphocytes; antigen-specific receptors; antibodies

innate immune system

response time: minutes to hours specificity: limited and fixed response to repeat infection: same each time major components: barriers (eg, skin); phagocytes; pattern recognition molecules

explain how oxygen is transported through the body. make sure to explain in detail the role of hemoglobin, including (1) its structure, (2) what determines the saturation of hemoglobin, and (3) what promotes the release of oxygen by hemoglobin in tissues

several factors that controlling the binding affinity of hemoglobin for oxygen and anything that causes a decrease in affinity will cause more oxygen to be released. usually most of blood is not deoxygenated, there is lots of o2 in there, when the blood is being brought back to the lungs (big reserve). if exercising heavily, then po2 inside tissues, which decreases the affinity of hemoglobin for oxygen if its going to be released. but also, since tissues are highly metabolic, there is more co2, more acidity, lower pH, increased temp, all of these are reducing the affinity of hemoglobin for oxygen, so in highly metabolic tissue, not only is there lower po2, but there is also a shift and released more oxygen than normal b/c of other characteristics of highly metabolic tissue.

filtration occurs at the filtration membrane, which consists of

the fenestrated endothelium of the glomerulus, the filtration slits of the podocytes found within the visceral glomerular capsule, and the porous basement membrane found between these two cell layers

glomerular filtration

the passage of water and water-soluble components from the plasma into the renal tubule the process that your kidneys filter excess fluid and waste products of the blood into the urine collecting tubules of the kidney, so they may be eliminated from your body

explain why humans cannot drink seawater to quench their thirst

to get rid of the excess salt our body will need more water than what we take in, so we will end up losing water limit to how concentrated we can make our urine in terms of water resorption and secretion or salts (too many salts) make cells hypertonic and overload the filtration system in order to filter out salt we would have to drink a bunch of fresh water to drive it out

there are several genetic diseases that affect the production and activation of lymphocytes. predict the impact of the following genetic mutations on the production and activation of lymphocytes (if any), and what symptoms you might expect from individuals with these mutations. (a) mutations that prevent the randomized b and t cell receptor rearrangements that typically diversify lymphocyte receptors. (b) mutations that prevent the elimination of some (though not all) lymphocytes that recognize self-antigens.

(a) cant make a receptor without that process, which means you aren't going to get any b or t cells. which means there will be no adaptive response to antigens and no memory, only be innate immunity. severe combined immunodeficiency (scid). they isolate these children with it (mostly x-linked). there are different treatment options like a bone marrow transplant=> removing all this persons original bone marrow (via radiation) and then you add bone marrow from someone else, as long as that bone marrow doesn't attack those recipients (key problem) then it can reconstitute the entire immune system including b and t cells which will be normal. the problem is that then certain molecules have to be identical to the person receiving the transplant with the person giving it (most likely siblings over anyone else). trying to get the exact match can be such a problem, instead now they know the genes that are gone, if they put those back with gene therapy through stem cells and then we can put those back in the person. a lot of the techniques that people use to do this, increase the risks of leukemia, so this person has no immune system and dies of leukemia. if you dont have t cells you can activate b cells either. might have production of b cells but no activation without t cells (b) can rearrange the receptors, but you don't get rid of all the ones that recognize self-antigens. process of getting receptors is randomized, so that is bound to have some that will recognize self-antigens, but in the case of eliminating some lymphocytes that recognize self-antigens, the body will attack its own cells. there is a disease in which it gets rid of most, but not all of the cells that recognize you, and that causes several autoimmune diseases (where b and t cells are attacking themselves) typically its things that are found in glands, so you end up with some that attack the parietal cells in the stomach, and the insulin cells in the pancreas, cells in retina of eyes. a bunch of autoimmune diseases that can't recognize their own cells. specifically with t cells b/c some of the t cells kill cells with the antigen inside of them, so if it's killing the parietal cells in the stomach, or beta cells in pancreas, or rods and cones in eyes, these are going to have some serious impacts.

difference between the innate and adaptive immune responses in how pathogens are recognized. (a) Which of the patterns of receptor expression represent innate immune cells? (b) Which of the patterns of receptor expression represent b and t cells?

(a) need all the receptors b/c they are prepared for all problems that could happen. they aren't looking for anything specific, but just very ready for any sort of attack with all the receptors on them. need all receptors to recognize all threats. no memory (like the national guard, going in there ready for anything) no randomization (b) specific target and go after one specific thing and try to affect as few other things as possible. randomization, due to having a number of enzyme evolving through a cut and paste mechanism, a specific part of the genome (just the t cell part of the genes or just in the b cell genes). they come in and cut and paste and add nucleotides, so it is very unlikely that there will be the same receptor twice due to the diversity of this process. inevitably, there is going to be something that binds to parts of our own proteins and we have to get rid of the cells that recognize parts of us. those all die by apoptosis (most of them). the rest of them that has been developed, they have never seen their antigen before (most wont get activated), but when they encounter the antigen and get activated and form an army, all of which just recognize that pathogen or antigen and can help produce a bunch of antibodies that then do various things to that antigen (like preventing it from infecting another cell, promote phagocytosis) [FOR B CELLS ABOVE] [FOR T CELLS BELOW] a t cell that is activated by antigen can bind to a cell that has an antigen inside of it (a cell infected with a virus, or a cancer cell). they attack those cells and kill them

difference between the innate and adaptive immune responses in how pathogens are recognized (c) following an infection, how does the population of innate cells change (d) following an infection, how does the population of b and t lymphocytes change?

(c) not specific, no change, die kinda fast after they are used. largely similar (d) replication of b and t cells specific for that antigen, due to replication, there are different populations of b and t cells that recognize all the same antigen, some form memory cells, and some b cells form plasma cells, t cells go off and kill cells infected with the virus. when they get activated they divide and multiply a large number of times, which is one reason why in some sort of throat infection, or mono, swollen lymph nodes, there is this massive response happening in the lymph nodes closest to wherever the infection is happening. before the infection there are a bunch of naive cells (each one has a different receptor), however after there is still some naive cells the ones that didn't respond to that antigen, but the ones that were activated by that antigen are going to divide a bunch of times and going to have memory cells and some effector cells for a while.

how can adaptive cells recognize all foreign substances, without recognizing self molecules

- a single progenitor cell gives rise to a large number of lymphocytes, each with a different specificity - removal of potentially self-reactive immature lymphocytes by clonal deletion - pool of mature naive lymphocytes - proliferation and differentiation of activated specific lymphocytes to form a clone of effector cells

functions of the urinary system

-excretion of metabolic wastes -maintenance of water-salt balance -maintenance of acid-base balance -secretion of hormones -reabsorb filtered nutrients and synthesize vitamin d

You have a family member who recently began taking a drug that blocks proton pumps in the gastric parietal cells for gastroesophageal reflux disease (GERD), which is characterized by frequent "heartburn." A. How do inhibitors of gastric proton pumps reduce heartburn? B. How would you expect secretin production in the small intestine to change in your family member before and after taking the proton pump inhibitor? Explain your reasoning.

A. Heartburn occurs when there is reflux of material from the stomach (which is acidic) into the esophagus, which does not have the same protections against stomach acid that the stomach has, so this causes damage and pain. Gastric proton pump inhibitors reduce acid production so that the material moving back into the esophagus is not acidic or at least less acidic, reducing damage and pain. B. Secretin production in the intestine is induced by the acidity of the chyme entering the small intestine from the stomach.If the stomach is less acidic, this will reduce secretin production.Note that less secretin is needed because the material is less acidic and requires less HCO3-to neutralize.

Many people are impacted by kidney failure and thus need either a donor kidney or frequent dialysis treatments. People with kidney failure have a number of symptoms, including insomnia, fluid accumulation in various tissues, anemia, fatigue, nausea, and confusion. A. Why is the build-up of fluids in the body a symptom of kidney failure?Explain your reasoning. B. Why is anemia associated with kidney failure? Explain your reasoning.

A. One of the functions of the kidneys is to maintain osmolarity of body fluids and excreting extra fluids. In case of kidney failure, extra fluids will not be excreted and will buildup inside the body. B. The kidneys produce erythropoietin (EPO),and without this, the signal to produce red blood cells is diminished, decreasing numbers of red blood cells.

The loop of Henle and the convoluted tubules of the nephron can be affected by necrosis. Necrosis is the death of cells and eventually tissue. A. Based on your knowledge of the processes taking place in the nephron, what would be the consequence of necrosis in these sections of the nephron on the composition of the urine of the person affected? Explain your reasoning. B. What about the consequences on their health in general? Explain your reasoning.

A. The loop of Henle and the convoluted tubules of the nephron are the location of secretion and reabsorption. If these sections of the nephron were to be damaged, these two processes would no longer be taking place. The only process of the kidneys still taking place would be filtration. Secretion and reabsorption are meant to supplement filtration by bringing back into the capillaries products that were unnecessarily filtered out. Secretion is the additional removal of products still in the blood. The urine of a person could be too rich in some solutes and too poor in others. There may also be problems with volumes (water not being reabsorbed). Of course, if the nephron is damaged, the urine may not even be properly carried to the calyx of the kidney. B. Necrosis of the nephron could lead to the failure of the kidney, which can be lethal. The patient may need dialysis during the recovery period.

Patients with type II diabetes are resistant to insulin and thus have high blood glucose levels that can damage multiple tissues. One treatment for type II diabetes specifically inhibits thev urinaryNa+/glucose symporter. A. How would treatment with this type of inhibitor impact glucose levels in the blood and in the urine? B. Explain your reasoning(it may be useful to include a diagram, though this is not required).

A. This would increase the glucose levels in the urine and thus decrease glucose levels in the blood. B. In the kidney, the transporter is needed for the resorption of glucose from the kidney tubules into the blood vessels. Glucose is taken up at the luminal surface via secondary active transport with sodium. This secondary active transport is only possible due to the sodium potassium pump on the basal surface that pumps sodium out of the cell. This makes it favorable for sodium, and glucose along with it, to enter the cells that line the proximal convoluted tubule. Facilitated diffusion allows for glucose to leave the cell at the basal surface.In a person with type II diabetes, inhibition of this transporter would allow more glucose to exit the body via the urinary system, which would reduce blood glucose levels and thus reduce the likelihood of damage caused by prolonged and high glucose levels.

Why does it take approximately a week after infection for the benefits of an adaptive immune response to start to be felt, and what protects the individual until the adaptive immune system "kicks in"?

Before the establishment of an effector population of lymphocytes, several events must occur: (1) specific recognition of pathogen by lymphocyte receptors (clonal selection); (2) proliferation of pathogen-specific lymphocytes to expand responding populations (clonal expansion); and (3) differentiation into effector lymphocytes with the resulting establishment of an organized adaptive immune response.The innate immune system is able to recognize and destroy pathogens in a relatively non-specific manner until the adaptive immune system becomes functional

Staphylococcus aureusis a particularly effective pathogen because it employs a number of strategies that impair the functions of the immune system. One of these strategies involves production of complement inhibitors. How could complement inhibitors impair the function of the immune system and increase survival of S. aureus?

Complement can be activated in a couple of different ways, including through the binding of antibodies to their antigens and through direct binding to molecules on the microbes. In either case, the complement pathway consists of a series of steps, culminating in the formation of pores called membrane attack complexes in the microbial cell walls/membranes. Water then enters the cell, causing it to lyse. If S. aureuscan inhibit this process, they can prevent this mode of microbial killing. Note that complement also induces inflammation and promotes phagocytosis, so these processes would likely be impaired as well, increasing bacterial survival indirectly.

Some virus-infected cells and cancer cells do not express MHC I. Why might this be beneficial for the infected/cancerous cell?

If these cells cannot present endogenous antigens on MHC I, the cytotoxic T cells will not be able to recognize the infected/cancer cell as foreign and kill them. However, there is another mechanism (which we did not discuss in class) in which a different cell type, the natural killer cell, can identify cells that do not express MHC I and kill them.

Where does chemical digestion take place? Make sure to address each element of this meal, all enzymes that play a role in the breakdown of this meal as well as the organs that secrete them and the location of the chemical breakdown. Include the name of the cells of the stomach and pancreas that play a role in the digestion of this meal and all intermediate products from the chemical breakdown of the foods. Use an additional page as necessary.

Mouth: Salivary glands secrete amylase and lipase. Amylase breaks down starch to disaccharides. Lipase breaks down fats. Stomach: Pepsinogen is released by chief cells. HCl is released by parietal cells. HCl activates pepsinogen to pepsin. HCl denatures proteins. Proteins are digested to small peptides by pepsin. Small intestine: Presence of fats and proteins in the duodenum triggers release of CCK. CCK stimulates secretion by pancreatic acinar cells.Pancreatic amylase produced by acinar cells further breaks down starches to disaccharides.Lactase, maltase, and sucrase-isomaltase secreted by the small intestine break down disaccharides to monosaccharides. Monosaccharides can be absorbed.Peptidases secreted by the small intestine digest small peptides to amino acids.(Note that there are also pancreatic proteases and peptidases secreted by the acinar cells that participate in protein digestion.)Bile salts produced by the liver and concentrated by the gallbladder emulsify triglycerides into a suspension of small fat droplets. Pancreatic lipase produced by the acinar cells hydrolyzes triglycerides into monoglycerides and free fatty acids. Intestine forms chylomicrons from the monoglycerides and free fatty acids that are extruded into the lymphatic vessels.

Where does mechanical breakdown take place?Briefly explain how each relevant organ participates in mechanical digestion, and why this mechanical digestion is important for chemical digestion.

Mouth: chewing breaks foods into smaller particles Stomach: Churns and grinds food with gastric juices Small intestine: segmentation Mechanical digestion increases the surface area for the hydrolytic enzymes to function, thereby increasing the rate of chemical digestion dramatically

Usea flow chart to show the trajectory of oxygen from the outside environment to a target organ. Make sure to include all organs and vessels the oxygen goes through. Explain what carries the oxygen in detail.

Outside -> mouth/nose -> pharynx -> trachea -> main bronchus (L or R) -> bronchus -> bronchiole -> alveolus -> pulmonary capillary -> veinule -> pulmonary vein -> left atrium -> left ventricle -> aorta -> arteries -> arterioles -> systemic capillaries -> target tissue Oxygen is carried by thehemoglobin of the redbloodcells.

Your 1-year old nephew had to get their thymus removed after discovering it contained a tumor. An unfortunate side effect of removing the thymus is that your nephew is now more susceptible to getting sick. Why is this the case? In your answer, be sure to incorporate the following elements: B cells, helper T cells, antibodies, and antigen.

T cells are lymphocytes that develop and mature into naïve T cells in the thymus. In the absence of a thymus, no more T cells will be produced. In the absence of helper T cells, B cells cannot beactivated either, so he will be largely unable to produce antibodies in response to an infection. The antibodies normally bind antigens and inhibit their function and/or promote their phagocytosis or complement-mediated killing. Cytotoxic T cells normally kill virus-infected and tumor cells, both of which will also be dramatically reduced without T cell production.

In later stages of amyotrophic lateral sclerosis (ALS), patients lose strength in their diaphragms. How would reduced strength of the diaphragmaffect the breathing process? Be specific.

The diaphragm is the primary muscle needed for breathing. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity and decreasing the pressure in the cavity, causing air to enter the lungs due to the negative pressure gradient. If a person has lower diaphragm strength, this would likely reduce the change in volume of the thoracic cavity and thus decrease the amount of air movement into the lungs.

Explain why it is more difficult to breathe at high altitude than near the sea level. Make sure to incorporate the concept of pressure gradientsin your answer.

The higher the altitude, the lower the atmospheric pressure. The lower the atmospheric pressure, the smaller the difference between atmospheric pressure and intra-alveolar pressureduring inspiration. The smaller the difference, the shallower the gradient. The shallower the gradient, the more difficult breathing will be. Transport is faster with a steeper gradient.pressure in the thoracic cavity needs to be lower than the atmospheric pressure in order to inhaleatmospheric pressure is lower at high altitudesrecognition that it is harder to breathe when the atmospheric pressure is closer to the pressure in the thoracic cavity

A child with a history of pneumonia and ear infections comes into the hospital with yet another infection. Blood tests revealed that she has higher levels of IgM than normal, with no detectable IgA or IgG. How might this defect affect this child's ability to kill and/or neutralize antigens?Refer to specific subsets of antibodies and their functions in your answer.

Unlike IgG, IgM cannot cross the placenta, and unlike IgA, it cannot cross epithelial tissue. It also diffuses poorly out of blood or lymphatic vessels. Due to its low affinity for antigen, it alsopoorly opsonizes and neutralizestoxins/antigens. As such, the IgM produced will likely not be particularly effective in killing or neutralizing antigen function, though it will still be able to kill some microbes through activation of complement, which is something that IgM does well.

a) describe a possible mechanism through which adh could increase water resorption in the collecting duct. b) alcohol inhibits adh secretion. how would this impact water balance?

a) increase permeability aquaporins-> increasing osmosis, through a water channel, which facilitates the movement of water more aquaporins means we can facilitate osmosis faster collecting duct cells don't have aquaporins on the surface which means, they are are in vesicle in the cell b/c they are not at the surface yet unless there is adh production, which binds to a receptor and activates signaling, but this causes the vesicle with the aquaporin to diffuse with the plasma membrane at the apical surface (side facing urine) now facilitate movement faster b/c aquaporins are on that surface b) without adh, there is less water absorption, so secreting too much water causing dehydration. have lots urine its a diuretic, going to promote water loss

how would heavy use of antacids affect digestion

chemical digestion of proteins is altered but no interference with mechanical digestion increased risk of infection pepsin is not the only protein digesting enzyme (the ones produced by the pancreas)

why is carbon monoxide poisoning an important cause of asphyxiation?

displaces oxygen in the blood and deprives the heart, brain, and other vital organs of oxygen (lose consciousness and suffocate) body doesn't get enough oxygen to keep you from passing out knocks oxygen off hemoglobin tissue can't metabolize co bings better than o2

Gases diffuse in net fashion from areas of relatively high partial pressure to areas of relatively low partial pressure

within gas mixture within aqueous solutions across gas-water interfaces