Histo Exam 3 (Renal) pt 1
What strcutures make up the renal corspuscle
bowmans capsule and the glomerulus make up bowmans capsule.
What are the 3 portal systems in the body?
1 The hepatic portal vein carries blood from the capillaries in the intestines directly to the sinusoids of the liver, and this is the largests system 2 the pituitary gland has the hypophyseal portal veins that carry blood from the primary capillary plexus, the to the hypothalamus, to the second capillary plexus that is located in the anterior pituitary. 3 the renal portal system (which is the one we will discuss)
What is a medullary ray? Are these structures found in the renal lobe or the renal lobule?
At the core of the lobules, there is an extension of the collecting tubules, and these tubules are going to end up in the medulla. that is the medullary ray. this is where the urine filtrate is being formed and its collecting here and heading to the medulla. it is found in the lobule
Which vasculature do you find at the periphery of every renal LOBULE? What direction do this structures go?
Interlobular arteries. they go through afferent arterioles, and and these arterioles feed into renal corpuscles, and they empty into the glomerular capillaries, which is the glomerulus
What happens with mesangial cells in kidney disease?
In kidney disease, there can be overgrowth of the mesangial cells, which can lead to impinging on the capillaries, and it can slow down capillary flow.
What is the function of juxtaglomerular cells? Where are these cells derived from? Where do you commonly find these cells?
JG cells secrete renin to regulate blood pressure. these cells are derived from smooth mucle of the tunica media of the afferent arteriole, and these cells are most commonly found in the afferent arteriole (and they can be found in the efferent arteriole but its more rare)
Which of the cortical tubules are most abudant in histological section?
The PCT. most of the time when you have a histological section of the kidney, the PCTs will be longer and more abdundant than the DCTs. sometimes the only thing you will see are the PCTs.
Describe the venous return from the interlobular veins
The blood that empties into the interlobular vein empties into the arcuate vein, and then empties into the interlobar veins, then the anterior and posterior division veins, then they enter the renal veins. the renal veins enter into the IVC
What is the glomerular capillary surrounded by, and where does it feed into and empty?
The glomerular capillary is surrounded by renal corpucle, and it feeds into a tubular system to feed into the medulla and the loop of henle, and then into the collecting duct of the juxtaglomerular nephron.
What structues of the urinary system gets blocked by the ureter?
The kidney stones can block the ureter and cause pain, and they can also get stuck in the calices and pyramids. when the stones block areas like calices & pyramids, there can be issues becuase they come in from the back to decrease blood blood flow and increase the danger of infection.
Where is the vasa recta located? Describe its flow and structure.
The vasa recta is located in the medulla, and these are parallel vessels that are parallel to the loop . the blood from here goes back into the cortex and empties into the interlobular vein (sometimes they may enter through the arcuate vein, but usually they bypass this vein and enter into the interlobular vein
How do ionic charges do filtration within the kidney? Describe the difference between positive and negative charges through the filtration slit, and why does this occur
There is an ionic barrier, things that are positively chaged flow through easier than things that are negatively charged. the reason for this is because there is an anionic glycocalyx repels large anionic glycoproteins in the basal lamina, and they oppose the flow of anionic materials. so the positively charged go through and the negatively charged and maintained in the blood
What are podocytes? Where are these cells derived from?
These are cells tightly associated with the loops of the capillary tuft, aka the glomerular capillaries. the cells have little feet. These cells are derived from the cells making up Bowmans capsule, specifically the parietal layer of the bowmans capsule
What is the renal lobe?
This is the renal pyramid and all the cortex that is associated with it.
Describe the blood flow in the kidney
We start in the renal artery, which comes off the aorta. then the renal artery divides/segments into 2-3 parts, at the hilum then the renal pelvis, the arteries divide into interlobar arteries, which are between the renal pyramids and towards the corticomedullary junction, which is the area where the cortex and medulla meet. then the interlobar arteries divide to become arcuate arteries, and these arteries run the march along the corticomedullary junction. then the arcuate arteries divide to form the glomerulus, the glomerular capillaries. these arteries are located in the renal corpuscles. then the glomerular arteries leave the glomerulus and give rise to efferent arterioles then the efferent arterioles will then empty into capillaries that are in the medulla, which are called the vasa recta the efferent arterioles of the cortical nephrons also empty into the peritubular capillaries, which are located in the cortex.
how does the diet play a role in kidney formation? give a specific example of a food item that can contribute to stones.
When peopel consume dark beverages/sodas it can leads a residue that can give rise to stones.
What kind of substances are being pushed through the fenestrae? Describe the direction of flow.
With the pressure present between the capillary fenestrae, and then the water and dissolved fluids are being pushed through the capillary fenestrae, then through the basement membrane, then through the filtration slit, then the urinary space. the fluid goes from the capillary lumen to the unrary space, and then the fluid can drain into the PCT
When are you able to see the renal sinus?
You are only able to see the renal sinus when you remove all the blood vessels and the structures of the kidney, it is the empty space at the center of the kindey
Differentiate between a major and minor calyx.
a minor calyx is in direct conract with the tip of renal/medullary pyramid, which is called a renal papillae. the minor calices come together to form a major calyx. a major calyx dumps into the renal pelvis, which is a funnel shaped structure that brings urine into the ureter
Differentiate between a renal lobe and renal lobule
a renal lobe has the medulla pyramid and all the associated cortex the renal lobule however is only found in the cortes only, and it has the medullary ray with all the associated nephrons.
The interlobular arteries are coming off the _______ ______, and they are in the cortex
arcuate arteries
Describe the renal portal system
blood leaving the glomerulus travels through an efferent arteriole before surrounding the nephron in a capillary network called the vasa recta if its going ot the juxtaglomerular nephron. if the filtrate is going to a cortical neprhon, then its going to a peritubular capillary from the efferent ateriole these are 2 different capillary beds depending on which part of the kidney that you are in.
The kidneys filter _____. The kidneys are generally a _____ shape.
blood, bean
Describe the direction of fluid from the capillary lumen to the urinary space?
capillary, basal lamina, through the filtration slit, and into bowmans space.
Differeniate between collecting tubules and collecting ducts.
collecting tubules are found in the cortex, while collecting ducts are found in the medulla. this is becuase the collecting ducts are larger in the medulla.
What happens between the capillaries of the glomerulus?
filtration occurs in the spaces of the glomerular capillaries
Where do you primarily find collecting tubules?
in medullary rays
Describe the structure and function of a mesangial cell.
in terms of structure, they are pericyte like cells, with long thin processes for their function, they are important in support to suspend and organize the glomerulus, contract the capillaries to regulate the glomerular filtration rate, secrete ECM, prostaglandins and cytokines, and complete phagocytosis to clean the filtration barrier.
where are the peritubular capillaries located within the kidney? Where is the vasa recta within the kidney?
in the cortex. the vasa recta is in the medulla
Where does filtration occur?
in the glomerular capillaries
The collecting tubules that came off the DCt are found where?
in the medullary rays
Where is the bladder located?
in the pelvic cavity
In which part of the nephron does most of the reabsorption occur?
in the proximal convulated tubule, it does about 2/3 of the reabsorption occurs to go back into the blood.
Where does the renal artery split
in the renal sinus.
Describe the structures of the neprhon in order, starting with the interlobular artery.
interlobular artery affterent arteriole glomerulus capillaries efferent areriole urinary space renal corpuscle PCT thick descending limb thin limb loop of hendle thick ascending limb DCT collecting tubule to collecting duct
What is the overall function of the juxtoglomerular apparatus?
it helps with blood pressure regulation
What is the cortex?
it is the outer layer of the kidney- its all the material rind below the capsule of the kidney.
What is the difference between the juxtoglomerular nephron and the cortical nephron?
juxta means next to. a juxtaglomerular nephrons are located much closer in the kidney but the cortical nephrons are located farther out in the kidney the cortical nephron efferent arteriole will also dump into the peritubular capillaries that wrap around the renal rubules.
What cells hold the glomerular capillaries together?
masangial cells
What are mesangial cells? Where are these cells located?
mesangial cells are in the stalk of the mesangium within the glomerular capillary loops. these are supporting cells in the glomerulus.
How are mesangial cells related to contractile function and secretion?
mesangial cells can be related to blood pressure and they secrete various molecules. in regards to blood pressure, the mesangial cells can contract, and the glomerular capillaries will narrow, which impacts glomerular filtration rate and how fast the fluid can get through by narrowing the vessel and slowing the blood down through glomerular capillaries. in regards to secretion, they secrete extracellular matrix (ECM), cytokines, and prostagladins. the ECM they secrete replaces the basal lamina that may be lost during repair
The cells making up bowmans capsule are derived from where?
the visceral layer of bowmans capsule
In relation to its function, what structure will you see a lot of in the PCT lumen?
microvilli.
What is the protein slit diaphargam composed of? What is important about this molecule?
nephrin, and this protein is important becuase it can be prone to mutation, and when it mutates it can lead to kidney failure due to poor control of the filtration mechanism.
Describe how the divison to arcuate and interlobar arteries occurs
once the arteries have given rise to interlobar arteries, they divide nad give rise to an artery that arches over the renal pyramid, running between the cortex and the medulla. these are the arcuate arteries. coming off the arcuate arteries are interlobular ateries that run perpendicular to the arucuate arteries, and they go off into the cortex. they carry blood to where the blood is going to be filtered.
What are the toes of the primary processes called? Describe the interdigitations of these structures.
pedicels. The pedicels interdigitate with other pedicels from other primary processes. think about this like interlocking your fingers around a tube.
what are the portal vessel systems?
portal vessel systems send blood to multiple capillary beds without going to the heart first.
What is the main action occuring in the PCT? How does the shape of the PCT help the fluid?
reabsoprtion back into the blood mainly occurs here, and the wiggly shape of the PCT helps the fluid to stay there for a long time.
all the portions of the nephon have ________ epithelium, except for the _______, which has simple squamous epithelium
simple cubodial, thin loop of henle.
What is the function of mesangial cells? How do they play a role in debris elimination?
since these cells hold the glomerular capillaries together, they are able to slip their processes into this area and phagocytose the area to elminate the debris in the filtration slits. if there is a lot of debris, it will phagocytose most of the basal lamina and then rebuild the basal lamina, as well as the podocytes and endothelial cells. the fluid has to be clean or filtration wont occur well.
What tyep fo epithelium is found in Bowman's corpuscle?
sipmle squamous epithelium
Describe the flow of fluid from the glomerular capillary lumen to the unrary space
started from the capillary lumen, there is pressure, and the fluid goes to the basement lamina. then it goes through the filtration slits, and into bowmans space, and into the urinary space
How can we get rid of kidney stones?
surgery is one method when the stones are stuck in a tough areas that lead to decreased blood flow, a cut to the posterior lateal side of the kidney will allow for a new supply of blood. in a kidney being supplied with fresh blood, there is a white line that runs along the side to the back of the kidney. you see a wite line because there is slighly less blood supply between the anterior and posterior divisions. cutting along that white line will limit the amount of blood flow to get further into the kidney, and get the stones out. this was more of a method done.. back in the day. now a days, lithotripsy is more commonly done. the patient is a placed in a water bath, and they use ultrasound to break the stones apart with sound waves until the stones are small enough to pass through the ureter and go out. theres a lot less access to blood supply through this method.
The urinary pole indicates the beginning of which structure in the nephron?
the PCT
What is the difference between the lumens of the afferent and efferent arteriole?
the afferent arteriole is typically depicted with a wider lumen than the efferent because that is the way that is formed.
What are pedicels attached to?
the basement lamina
A glomerular capillary has its endothelial cell. Describe the structure of the capillary. What are the spaces called?
the capillary is fenestrated. there are fenestrae in the spaces.
What is the outermost layer of the kidney called? What type of tissue makes up this layer?
the capsule. it is made from dense connective tissue.
In terms of kidney structure, where does the collecting duct carry waste? What happens to the water content of the waste?
the collecting duct carries the urine to the medulla. the water content of the waste is changed before it is emptied out into the cortex and medulla, nad into the minor calyx.
Where do you find a collecting tubule in relation to a renal lobule?
the collecting tubules are in the medullar rays, specifically at the center of the renal lobules in the cortex.
Describe how the collecting tubules look in histological section
the collecting tubules have more clear boundaries between the nuclei compared to the PCT for example, and they dont have many organelles in their cytoplasm or mitochondria
What organ is located above the kidneys? What structure is beyond that?
the diaphragm is above the kidneys, and they sit directly on the posterior wall of the abominal cavity. the rib cage is beyond that.
What are the 3 cells contributing to the basal lamina in the kidney?
the endothelial cell, the podocyte, and the mesangial cell
How does the filtrate go through the urinary sinus prior to entering the PCT?
the filtrate goes through the sinus, into a filter before getting to the PCT.
What is the nephron?
the functional subunit of the kidney
What does the fused basal laminae contain? What kinds of molecules get through? How do podocytes attach to the basal lamina?
the fused basal lamina is from the endothelial cell and the podocyte. it contains collagen IV, laminin, fibronectin, and heparan SO4 proteoglycan. the podocytes attach to the basal lamina through integrin a3B1.
What surrounds the fenestrae of the glomerular capillary? Where does this structure originate from?
the fused double basal lamina. it comes from the podocytes and the endothelial cell.
What are 2 major functions of the kidney?
the kidney functions to clear toxins from the body and regulate blood pressure, in an endocrine fashion
What molecule does the kidney make in association with red blood cell development? Where do these signals originate?
the kidney make erythropoietin and it maintains/stimulate RBC development. the kidney is the one that regulates it, NOT THE BONE MARROW.
A renal LOBE is between _____ ____. The Interlobular arteries are located betwen the ___________.
the lobes are between the interlobar arteries. The interlobular arteries are between the lobules. be careful with the lobe and lobule for the kidney.
structurally, where does the loop of henle dip into and what is its main function? What happens when we leave the loop of henle?
the loop of henle dips into the medulla, and it is responsible for concentrating the urine. when we leave the loop, we go to the DCT, and then the waste is dumped into the collecting duct
When looking at a histologcial section, what can you expect to find the loop of henle next to? How does the loop of Henle appear in histological section?
the loop of henle is really small in histological section, and there is simple squamous epithelium. you would expect to see what looks like a capillary without the blood vells. you would see the loop of henle next to the vasa recta.
What structure is the defining factor for the DCT? Which pole is this structure always found in?
the macula densa, its always found in the vascular pole
What is the medulla? What are other names for the medulla?
the marrow is on the inside of the kidney. its also referred to as a the renal pyramid or the medullary pyramids
Among the general structures of the kidney, what structure holds the final concentration of urine? Where is the urine released from after this?
the medulla holds the final concentration of urine, and then the concentrated urine is released to the calices.
What is the mesangium?
the mesangium is the supporting structures of the vessels, and the mesangial cells are located within the mesangium.
What is one way of telling the urinary and vascular poles apart?
the vascular poles have the blood vessels, and there is blood entering on this side.
What types of molecules can go through the pores? What types of molecules CANNOT get through the pores?
the only thing that can go through these pores are fluids. not even small called like platelets or large cells like albumin can go through this barrier.
How does the plasma memrbane regulate separation within the PCT? Which other portion of the nephron has this highly folded plasma membrane?
the plasma membrane can help to maintain a difference between waht is the lumen and what is around the lumen, so that some contents like waste do not go back into the blood. the DCT also has this plasma membrane strcture.
What are the extensions of the podocyte cell body called?
the primary processes.
Where does the renal artery come off from? Describe its divisions when it comes off the renal sinus and how the interlobar ateries take place
the renal artery comes off the aorta. when this artery comes into the area of the renal sinus, it breaks up into an anterior posterior divisions for the front and back of the kidney respectively as they get into the cortex and the medulla. from there, they break up into interlobar arteries.
What is the importance of the covering of the filtration slit? What is the problem with this covering?
the slit por diaphragm (not sure if this is spelled right) covering the flitration slit, it limits what can leave the capillary and get into the lumen. a problem with this covering is that when there is debris in the blood, it can build up into the basal lamina.
Describe the structure for all the different components of the loop of Henle.
the thick descending limb of the loop of Henle has the same structure as the PCT the thin limb of the loop has a lot of fluid being exchanged. the thick ascending limb has the same histological structure as the DCT
What specifically makes the thin loop of henle thin in comparison to the other structures?
the thin loop of henle has simple squamous epithelium, while the other portions of the kidney have simple cubodial epithelium
What is the urinary pole? What is the vascular pole?
the urinary pole is where the ruinary space empties into the proximal tubule. the vascular pole is usuallly 180 degrees in the opposite direction of the urinary pole, its where affferent comes in and efferent comes out.
the glomerulus sits in which space?
the urinary space.
What pole is the macula densa part of? Which system is it apart of?
the vascular pole. this is the defining feature of the vascular pole. its part of the blood pressure regualting system
What type of tissue surrounds the capsule? what is the function of this tissue and why is this function so important?
there are fat pads around the capsule, and it protects the kidney from truama. there are a lot of capillaries around the kidney, and when the capillaries are damaged there can be internal bleeding that can be hard to control .
Describe the pressure differentials assocaited with starting filtration
there are lot of pressure in the glomerular capillaries. there is backpressure here becuase you have a wider arteriole giving rise to a smaller arteriole, and that can lead to back pressure. this forces the fluid from the blood out into the renal sinus.
What is the difference between the renal corpuscles in the medulla vs in the cortex?
there are no renal corpuscles in the medulla but they are present in the cortex
what is the difference in the amont of microvilli and mitochondria seen in the DCT compared to the PCT?
there is less mitochondria, and the microvilli are much smaller. you dont see the microvilli as much in the lumen compared to the mitochondria.
within the nephron, if there is an abdundance of mitochonidria, what type of stain color do you expect to see?
there should be more pink/orange cytoplasm with increased amounts of mitochondria.
How are mesangial cells related to phagocytosis? how can this also be related to the immune system?
these are the cells that phagocytose material off the basal lamina. if a person has a life theatening infection, there are lots of antibodies in the blood to that bacteria. the cells collect on the filtrration barrier. sometimes there can be so much infection that it impacts the mesangial cell's ability to clear the infection.. so the immune system can come in and destroy those antibodies. theyll destroy portions of the filtration barrier and allow blood and large molecules into the urine. this can lead to kidney failure. this is what happens in sepsis. the infection continues thriving inside of the body, which is why sepsis can be so impactful. you would have to treat the kidneys first and put the patient on dialysis to prevent the person from going into renal failure.
Describe the appearance of the nuclei for the PCT. Why do the nuclei appear this way, and what does this mean?
these nuclei are pushed off the base of the cell. they are pushed up becuase there are infoldings of the plasma membrane that interdigitate with the mitochondria. the interdigitation indicates that the cell is involved with pumping and these cells are pumping ions from the fluid, picked up by capillaries surrounding the peritubular capillaries.
What are the spaces ebtwen the pedicels called?
they are called filtration slits, and they are apart of the filtration process.
The interlobar arteries are located between the ______. What arteries do they give rise to?
they are located between the lobes (the renal lobes). they give rise to the arcuate arteries.
Where do the collecting tubules carry filtrate?
they carry filtrate from the DCT to the collecting ducts in the medilla.
Describe how the interlobular arteries run in comparison to the arucate arteries. What is the function of these arteries?
they run perendicular to the arcuate arteries and feed into the cortex. they take the blood where it is going to be filtered.
What is the renal sinus/urinary sinus? What is another name for the structure?
this is the C shaped area surrounding the glomerulus. it is also called the urinary sinus.
Blood that leaves a capillary bed in the kidney (specifically the glomerulus in the kidney) is going where?
to the efferent arteriole, NOT A VEIN.
Where is the urine made, and what direction does it go to exit?
urine is made in the pelvis and its drained down towards the bladder, and the urine exits the body through the urethra
During ionic filtration in the kidney, what molecules are permeable through the fenestrae?
water, urea, glucose, salts, and small proteins
What are the 4 organs associated with the urinary system? Describe the generalflow of urine from the kidneys to the urethra
we have the kidneys, which is where the urine is made, then the ureters, to the unrary bladder, and then the urine leaves out through the urethra. these are the 4 structures that are involved in the unrary system
Where could you have columnar cells within the nephron?
within humans and large animals, at the end of the collecting tubules they empty into the minor calyx, and theres often times columnar epithelium in the papillary ducts of the medulla.
