Mar 24th- 28th Renal Flashcards
- Explain the concept of balance as it applies to physiology, and give an example of a specific substance that the kidneys keep in balance.
The balance concept states that our bodies are in balance for any substance when the inputs and outputs are matched, an example could be water balance that is established by the filtering of the kidneys (maintaining homeostasis)
- List and describe seven major functions of the kidneys.
- Regulation of water and electrolyte balance: maintain appropriate water and electrolyte levels
- Regulation of acid-base balance: keep pH in biologically appropriate range (important
- Excretion of metabolic waste and bioactive substances: ridding body of harmful substances (important for hormone clearance)
- Regulation of arterial blood pressure: kidneys maintain an appropriate blood volume for adequate blood pressure, generate vasoactive substrates
- Regulation of red blood cell production: erythropoietin produced in the kidney helps to control RBC production by stimulating the bone marrow
- Regulation of vitamin D production: kidney completes the last biochemical transformation to the active form of vitamin D
- Gluconeogensis: during a prolonged fast, a substantial amount to gluconeogenesis occurs in the liver
- Describe the hormonal mechanism by which the kidneys regulate red blood cell production.
Erythropoietin, peptide hormone controls RBC production by the bone marrow
medullary interstitial cells release erythropoietin in response to hypoxia
- Define and state the functional relationships between the following urinary system structures:
kidney, hilum, ureter, bladder, calyx, renal pyramids, renal papilla, renal medulla, renal
cortex, renal interstitium.
Hilum: indented surface that faces the spine, penetrated by blood vessels, nerves and a ureter which carries urine to the bladder
Each ureter is formed from funnel-like structures called major calyces, which in turn are formed from minor calyces (calyces act to collect urine from the pyramids, fitting over underlying cone shaped renal tissue called pyramids, the tip of the calyx is called the papilla and projects into the minor calyx
The pyramids constitute the medulla of the kidney, overlying the medullary tissue (visible pyramid structure) is a cortex (more granular)
10% of the renal value is the tissue between the blood vessels and the tubules (an extracellular matrix of collagen, proteoglycans and glycoproteins
- Identify and state the functional relationships between the following structures:
Nephron, renal corpuscle, collecting duct, Bowman’s capsule, glomerulus, afferent
arteriole, efferent arteriole, Bowman’s space
each nephron begins with a spherical filtering component called the renal corpuscle, the hollow sphere is Bowman’s capsule filled with capillary loops called the glomerulus, blood enters the capsule via afferent arteriole and leaves through a efferent arteriole; the space not occupied by glomerulus is called the urinary space or Bowman’s space
the capsule is followed by a long tubule leading out of it that continues until it merges with tubules of other nephrons to form collecting ducts
- Distinguish between a juxtamedullary nephron and a cortical (superficial) nephron, in terms of both their structure and function.
jutamedullary are closer to the medulla, have longer loops of Henle that contribute to system that concentrates urine (they are fewer in number) cortical nephrons are more superficial and their loops spend less time in the medulla
- Put the following structures in the order encountered by a filtered substance that leaves the body:
Bowman’s space, proximal tubule, descending loop of Henle, thin ascending loop of Henle, thick ascending loop of Henle, juxtaglomerular apparatus, distal convoluted tubule, cortical collecting duct, medullary collecting duct
- List the 3 cell types that make up the juxtaglomerular apparatus, and describe the major function of each
Granular cells (jutamedullary cells): contain secretory vesicles containing renin
Extraglomerular mesangial cells: phagocytotic cells outside the glomerulus
Macula densa: detect the compositon of the fluid within the nephron at the very end of the thick ascending limb and contribute to control of the GFR as it relates to renin secretion
- Differentiate between the processes of renal filtration, secretion, reabsorption and excretion.
Filtration is the process by which water and solutes in the blood leave the vascular system through the filtration barrier and enter bowman’s space
Secretion is the process of moving substances into the tubular lumen from the cytosol of epithelial cells that form the walls of the nephron (moves things out more quickly than simple filtration)
Reabsorption is the process of moving substances from the lumen across the epithelial layer into the surrounding interstitium
Excretion mans exit of the substance from the body (tubule is outside the body
- Compare the composition of the fluids in glomerular capillaries and Bowman’s capsule.
The glomerular filtrate is very much like blood plasma but contains very little protein (virtually no large proteins and very small numbers of small proteins)
- Define “freely” filtered.
Substances that are virtually the same concentrations in the filtrate as in the plasma are said to be freely filtered- as free as water is to move
- State the normal values of the glomerular filtration rate (GFR) in a healthy young adult male in mL/min, and in L/day, and compare the latter number to the daily rate of net fluid filtration across all of the body’s capillaries combined.
180 L/ day or 125 mL/ min compared to the 4L per day net filtration across all other capillaries in the body
- Compare the volume of fluid filtered at the glomerulus each day to the total body fluid volume.
Normal plasma volume is 3L which means that the total volume is filtered 60x a day
- List the percentages of filtered Na+, H20, Glucose, and urea that are reabsorbed by the nephron in an average, normally hydrated person.
Na+ 99.5%
H2O 99%
Glucose 100%
- In each of the blanks below, put the structure from this list that best corresponds:
Glomerulus, proximal tubule, loop of Henle, distal tubule, collecting duct
___greatest mass of excreted substances enter the nephron
___reabsorption of 67% of filtered H20, Na+ and Cl-
__reabsorption of useful organic molecules
___secretion of organic wastes, drugs, toxins
___reabsorbs 20% of filtered NaCl and 10% of filtered H20
___reabsorbs ~5% of filtered NaCl
___plays a major role in urea regulation
____glomerulus______greatest mass of excreted substances enter the nephron
_____prox CT_____reabsorption of 67% of filtered H20, Na+ and Cl-
¬_____prox _____reabsorption of useful organic molecules
_____prox_____secretion of organic wastes, drugs, toxins
_____thick AL_____reabsorbs 20% of filtered NaCl and 10% of filtered H20
_____distal tubuels and collecting duct together_____reabsorbs ~5% of filtered NaCl
______medullary collecting duct____plays a major role in urea regulation
