WEEK 1- urinary system, anatomy+histology Flashcards
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list some functions of the kidneys
-regulation of blood ionic comp, blood ph, blood volume, blood pressure.
-production of hormones
-activating vitamin D
describe the location, tissue composition and function of the renal capsule
-it is the outermost layer of the kidney directly in contact with the kidney’s surface.
-consists of thing, tough layer of dense irregular connective tissue
-the function is to provode a protective barrier that shields the kidney from physical trauma and helps maintain its shape
describe the location, tissue composition and function of the adipose capsule;
-it is located between the renal fascia and renal capsule
-this capsule is composed of fatty tissue, adipocytes and connective tissue
-function is to serve as a cushion to protect the kidneys from physical shock and trauma
describe the location, tissue composition and function of the renal fascia
-surrounds the kidney and the adipose capsule
-this fascia is made of dense irregular connective tissue
-function is that this helps provide structural support and helps keep the kidney in place within the abdominal cavity and seperates the kidney from adjacent structures which helps limit spread of infections.
describe the location, and function of the renal cortex
-this is the outer layer of the kidney located beneath the renal capsule, it is the outermost portion of the kidney
describe the location, and function of the renal papilla
-is the tip or apex of each renal pyramid. it points towards the center of the kidney and projects into the minor calyx
describe the location, tissue composition and function of the renal column
-the renal column are the extensions of the renal cortex that dip between the renal pyramids, running between them and extending into the medulla.
-they help in providing a pathway for blood vessels and interstitial tissue of the kidney
describe the location, tissue composition and function of the renal pelvis
-located in the central part of the kidney, at the hilum where the kidney connects from the major calyces and channels it into the ureter. (collects urine from papilla)
describe the location and tissue comp of the urethra
-is the tube that carries urine from the bladder to the outside of the body
-composed of transitional/stratified squamous epithelium, smooth muscle and connective tissue
describe the location and tissue comp of the bladder
-is a pelvic cavity sac for urine storage; composed of transitional epithelium, smooth muscle and connective tissue
describe the location and tissue comp of the ureters
-tube-like structures from the kidneys to bladder; composed of transitional epithelium, smooth muscle and connective tissue
define transitional epithelium
it is a type of epithelial tissue specialized to accomodate flucuations in volume.
-this epithelium is typicially multilayered w/ cells that can vary in shape depending on degree of stretch
define trigone
-it is a triangular area on the internal surface of the bladder it is defined by the openings of the ureters
-located at the based of the bladder
-it helps to ensure that urine is directed efficiently from the bladder into the urethra and prevents backflow of urine into the ureters.
compare and contrast the male urethra and the female urethra
-both help urine leave the body from the bladder
-both exhibit changes in epithelial lining as they transition from the bladder to the external opening
-female urethra is much shorter (3-4cm long) and it extends from the bladder to external urethral oriface
-female urethra only serves as a conduit for urine and has no role in reproduction
-male urethra is longer (18-22cm long) and is divided into several parts
-male urethra coveys urine from bladder and also serves as a passage for semen therefore has a role in reproduction.
what is a nephron
a functional unit of the kidney
define the renal corpuscle and list the components of it
-is a crucial component of the nephron
-components include;
-glomerulus; which is a network of capillaries located within the renal corpuscle, function is to filter blood to form glomerular filtrate that will eventually become urine
-glomerular capsule; is a double walled cup-like structure that encloses the glomerulus, function is to collect filtrate that is pushes out of glomerulus and directs it into renal tubules.
what is the filtration membrane? and list its three main components
this membrane is a criticial barrier that seperates blood in the glomerular capillaries from the filtrate in the bowman’s capsule
three main components include;
1) endothelium of glomerular capillaries; consist of single layer of endothelial cells that have small pores allowing passage of water, etc and blocking out blood cells and proteins
2)basement membrane; is a thick extracellular matrix located between the endothelium and podocytes. it acts as a selective fliter preventing passagae of larger proteins and allowing smaller molecules to pass thru
3)podocytes; are specialized epithelial cells with pedicels, podocytes help further refine the filtration process by preventing passage of medium sized proteins.
define the renal artery
it branches directly from the abdominal aorta and suppplies blood to each kidney. it delivers oxygenated blood from the heart to the kidneys for filtration
define the renal vein
drains blood from the kidneys into the inferior vena cava, carries deoxygenated blood away from the kidneys and back to the heart
define segmental arteries
branch off from the renal artery and enter the kidney at the helium. function is to supply blood to different segments of the kidney
define interlobar arteries/veins
run between the renal pyramids in the renal columns. the interlobar arteries branch from segmental arteries and supply blood to the renal cortex/medulla. the interlobar arteries drain blood from these area
define arcuate arteries/veins
they each arch along the boundary between the renal cortex+medulla the arteries supply blood to the renal cortex and veins collect blood from the cortical radiate veins and drain into the interlobar veins
define cortical radiate arteries/veins
these are found within the renal cortex, the arteries supply blood to glomeruli within nephron units the veins drain blood from pertubular capillaries
define afferent arteriole
branch from the cortical radiate arteries and lead to the glomeruli, carry blood to the glomerular capillaries where filtration occurs
define glomerular capillaries
network of capillares located within the glomerulus of each nephron this is where blood filteration takes place allowing water/small solutes to pass
define efferent arteriole
they exit the glomerulus and carry blood away from glomerular capillaries. directs filtered blood from gomerulus to pertubular capillaries or vasa recta
define pertubular capillaries
surround the nephron tubules in renal cortex. involved in reabsorption of water, ions, etc.
comapre the visceral and parietal layers of the glomerular capsule
1)visceral layer- directly covers the glomerulus, consists of podocytes and their foot processes (pedicels) that create filtration slits. this layer is crucial for the filtration of blood as the podocytes play a key role in filtering out molecules
2)parietal layer-forms the outer wall of the glomerular capsule, composed of simple squamous epithelium this layer is primarily structural, providing a barrier that contains and directs the filtrate into renal tubules
for the following nephron component describe their epithelium and relative location in the kidney/nephron; PCT
-proximal convoluted tubule;
-has simple cuboidal epithelium
-located after the glomerular capsule and first segment of the renal tubule in the nephron
-located in the renal cortex in the kidney.
for the following nephron component describe their epithelium and relative location in the kidney/nephron; descending limb of the nephron loop
-simple squamous epithelium
-extends from proximal straight portion of the PCT in the nephron
-located in the renal medulla in the kidney
for the following nephron component describe their epithelium and relative location in the kidney/nephron; ascending limb of the nephron loop
-simple cubodial to columnar epithelial cells are thicker comapred to descending limb
-begins at the end of decending limb and ascends back towards renal cortex in the nephron
-transitions from medulla back the cortex in kidney
for the following nephron component describe their epithelium and relative location in the kidney/nephron; DCT (distal convuluted tubule
-simple cubodial epithelium
-the DCT is located after the ascending limb of the loop before connecting tubules in the nephron
-located in the renal cortex in kidney
describe in detail the arrangement of the renal corpuscle to include the relative positions of; afferent arteriole
location; enters the renal corpuscle and branches into the glomerular capillaries.
funciton; supplies blood to the glomerulas
for the following nephron component describe their epithelium and relative location in the kidney/nephron; collecting duct (CD)
-simple cubodial to columnar epithelium
-channels into renal pelvis in the nephron
-extends from renal cortex into renal medulla where it coverges into the renal pelvis
describe in detail the arrangement of the renal corpuscle to include the relative positions of; efferent arteriole
location; exits the renal corpuscle, carrying blood away from the glomerulas after filtration.
function; drains blood from the glomerular capillaries
describe in detail the arrangement of the renal corpuscle to include the relative positions of; glomerular capillaries
location; located within the glomerulas these are the network of tiny blood vessels where filtration occurs
function; filters blood allowing water and small solutes to pass into the bowmans capsule while retaining larger molecules and cells
describe in detail the arrangement of the renal corpuscle to include the relative positions of; podocytes (visceral layer of the glomerular capsule)
location;visceral layer of the glomerular capsule directly covers the glomerular capillaaries
function; podocytes form filtration slits that control passage of molecules
describe in detail the arrangement of the renal corpuscle to include the relative positions of; parietal layer of the glomerular capsule
location; forms the outer wall of the bowmans capusle
function; this layer helps support and helps direct the filtrate into the renal tubule
describe in detail the arrangement of the renal corpuscle to include the relative positions of; ascending limb of the nephron loop
location; begins after the descending limb and ascends back towards the renal cortex
describe in detail the arrangement of the renal corpuscle to include the relative positions of; macula densa
location; located in the distal convulted tubule where it comes in cotnact w/ the afferent and efferent arterioles
function; moniters sodium chloride concen in the filtrate and signals juxtaglomerular cells to adjust blood pressure and filtration rate
describe in detail the arrangement of the renal corpuscle to include the relative positions of; juxtaglomerular appartus/cells (JGA)
location; found in the region where the distal conc=vulted tubule contacts the afferent arteioles
function; regulates blood pressure and glomerular filtration rate by rsponfing to changes in blood pressure and sodium concentration.
describe in detail the arrangement of the renal corpuscle to include the relative positions of; mesangial cells
location; situated between the glomerular cappliaries within the glomerulas
function; provides structural support helps regulate golmerular filtration by contrating + relaxing
define renin
hormone prodcued by juxtaglomerular cells that regulates blood pressure by activating angiotensin
compare and contrast gomerular filtration, tubular reabsorption and tubular secreation
glomerular filtration; movement of fluid and solutes from the blood into bowmans capsule
tubular reabsorption; movement of substances from the tubular fluid back into the blood
tubular secreation; movement of substances from the blood into the tubular fluid for excretion
pressures involved in filtration; glomerular blood hydrostatic pressure (CBHP)
blood pressure in capillaries
pressures involved in filtration; capsular hydrostatic pressure (CHP)
pressure exerted by fluid in the bowmans capsule
pressures involved in filtration; blood colloid osomotic pressure (BCOP)
osmotic pressure from proteins in the blood
pressures involved in filtration; capsular osomotic pressure
low osomotic pressure in the capsule
passive vs active transport
active transport- requires energy (ATP) to move substances against their concen. gradient (from low to high concen) e.g sodium potassium pump
passiventransport- does not require energy substances move down their concen. gradient (from high to low concen.) e.g simple diffusion, facillitated diffusion, osmosis.
describe the permeability of the following molecules; small non polar gases, ions, large polar molecules.
small non polar gases; highly permeable, these molecules easily diffuse across the lipid bilayer
ions- impermeable, ions cannot cross membrane freely and require specific channels or transporters because they are charged
large, polar molecules; impermeable these molecules require facillitated diffusion via carrier proteins or active transport mechanisms
what are channel transporters
-allow specific ions or molecules to pass thru membrane
-passive allowing ions to flow down their concen. gradient
-e.g na+ and k+ channels
what are carrier proteins
-bind to specific molecules and undergo a conformational change to transport them
-can be passive or active
-e.g glucose transporters
what are pump transporters
-active transporters that use ATP to move ions or molecules against their concen. gradient
-e.g na+/k+ pump which moves 3 na+ out of the cell and 2 k+ into the cell
what are pumps transporters
-active transporters that use ATP TO MOVE IONS or molecules against their concen. gradient
-e.g is a na+/k+ pump
what are symporter transporters
-move 2 or more substances in the same direction across the membrane
-e.g na+/glucose symporter in the pct
what are antiporters
Move two or more substances in opposite directions.
Example: Na+/H+ antiporter, which moves Na+ into the cell while moving H+ out.
describe the arrangement of ions around the cell membrane
Outside the cell: High concentration of Na+ and Cl- ions.
Inside the cell: High concentration of K+ ions and negatively charged proteins.
The sodium-potassium pump helps maintain this gradient by moving Na+ out and K+ in.
paracellular vs transcellular transport
Paracellular Transport: Movement of substances between adjacent cells through tight junctions.
Transcellular Transport: Movement of substances across the cell, through both the apical and basolateral membranes of the epithelial cells.
what is the na+/glucose pathway
Sodium and glucose are reabsorbed together via a Na+/glucose symporter.
Sodium moves down its gradient, providing energy for glucose to move against its gradient.
h20 in the PCT
Water follows the reabsorption of sodium through osmosis, primarily via aquaporins (water channels).
lipid soluble substances
Reabsorbed by simple diffusion as they can pass freely through the lipid bilayer of cells.
how are cl-, ca2+, k+ and urea reabsorbed
Reabsorbed through both paracellular and transcellular pathways depending on their gradients.
what is an aquaporin
Aquaporins are specialized water channels that facilitate the passive transport of water across the cell membrane.
what is the renal medulla
-the inner region of the kidney beneath the renal cortex
-plays role in concentrating urine and regulates water balance
