The Kidneys and Associated Structures Flashcards
What is the kidney tissue very similar to?
retinal tissue
-retinopathy and nephropathy go hand in hand
kidneys overview
- controlling water and electrolyte balance
- maintaining acid-base balance of the blood
- waste leaves as urine out of ureters to bladder
- urine leaves the body in the urethra
Kidney position
-lie behind the peritoneum high up on the posterior abdominal wall on either side of the vertebral column
Which kidney sits higher?
left because of the left lobe of the liver
do the kidneys move at all?
with contraction of the diaphragm during respiration, both kidneys move downward in a vertical direction by as much as 1inch
hilum
- doorway that structures pass in and out of the kidney
- extends into the renal sinus
- transmits, from front to back, the renal vein, two branches of the renal artery, the ureter, and the third branch of the renal artery.
- lymph vessels and sympathetic fibers also pass through here
renal sinus
-formed by the invagination
right kidney: anteriorly
- the suprarenal gland
- liver
- second part of the duodenum
- right colic flexure
right kidney: posteriorly
- diaphragm
- costodiaphragmatic recess of the pleura
- the 12th rib
- psoas, quadras lumborum, and transversus abdominus muscles
- subcostal (T12), iliohypogastric, and iliinguinal nerves (L1) run downward and laterally
Left kidney: anteriorly
- suprarenal gland
- spleen
- stomach
- pancreas tail
- left colic fixture
- coils of jejunum
left kidney: posteriorly
- diaphragm
- costodiaphragmatic recess of the pleura
- the 11th and 12th ribs
- psoas, quadras lumborum, and transversus abdominus muscles
- subcostal (T12), iliohypogastric, and iliinguinal nerves (L1) run downward and laterally
covering of the kidneys
- fibrous capsule
- perirenal fat
- renal fascia
- pararenal fat
fibrous capsule of the kidney
-surrounds the kidney and is closely applied to its outer surface
Perirenal fat
covers the fibrous capsule
renal fascia
condensation of CT that lies outside the perirenal fattened encloses the kidneys and the suprarenal glands. it is continuous laterally with the fascia transversalis
pararenal fat
lies external to the renal fascia and i often in large quantity. it forms part of the retroperitoneal fat
renal structure
- light outer cortex
- dark inner medulla
- renal pyramids in medulla
- renal papilla-apex of pyramid
- renal columns-cortex between the pyramids
Where does the apex of the renal pyramid face?
always the hilum
base towards the cortex
-funnels things through the renal papilla
renal sinus
- space within the hilum
- contains the upper expanded end of the ureter (the renal pelvis)
divisions of the renal pelvis
Major calyces, each divide into 2 or 3 minor calyces
What does the renal artery divide into at the kidney?
segmental arteries
What do the segmental arteries break down into?
lobar arteries BEFORE the kidney. one for each pyramid
what do the lobar arteries branch off into?
interlobar arteries. run towards the cortex on each side of the renal pyramid
arcuate arteries
at the junction of the cortex and the medulla, the interloper arteries give off these. they arch over the bases of the pyramids
interlobular arteries
comes off of the arcuate arteries
ascend in the cortex.
afferent glomerular arterioles
arise from the branches of the interlobular arteries that come off of the arcuate artery
renal artery
- arises from the aorta at level L2
- usually divides into 5 segmental arteries that enter the hilum of the kidney, they are distributed to different segments or areas of the kidney
What is the renal cortex comprised of?
- renal corpuscles
- proximal and distal convoluted tubules
- cortical collecting tubules
- blood vessels
what is the renal medulla composed of?
- renal pyramids
- descending limb of the loop of henle
- ascending limb of the loop of henle
- cortical collecting tubules
- collecting ducts
- papillary ducts
direction of urine in the kidneys
-papillary ducts drain urine into the minor calyces and then to the major calyces; the major calyces merge into the renal pelvis, which drains urine into the renal ureter
podocytes
- form sieve in capillaries to catch any of the nutrients that might need to come back
- have a long, interdigitating cellular process
- play an important role in blood filtration
What happens in DM neuropathy?
the podocytes allow big things like proteins to go through, when they should not
What filters into the bowman’s capsule?
EVERYTHING from the blood (except blood components)
bowmans capsule if toxin cxn is high
higher pressure forces the toxins out of blood
What are the two main functions of kidneys?
- filter blood
- maintain hydration
nephron
- basic functional unit of the kidney
- comprised of a renal corpuscle, a proximal convoluted tubule, a loop of henle, and a distal convoluted tubule
renal corpuscle
composed of a glomerulus and a bowman capsule
glomerulus
consists of a spherical knot of capillaries, which is fed by an AFFERENT arteriole and drained by an EFFERENT arteriole at the vascular pole.
Bowman capsule
-visceral and parietal layer
visceral layer of the bowman capsule
composed of podocytes, which cover the capillaries of a glomerulus
intraglomerular mesangial cells
interstitial tissues surrounding the glomerular capillaries contain thises
parietal layer of the bowman capsule
hollow spherical structure lined by simple squamous epitheliem
What is the space between the visceral and parietal layers of the bowman capsule?
bowman space
glomerulus filtration
- blood flows through glomerular capillaries
- plasma passes through the glomerular filtration barrier
- filtration is collected in the bowman space
- renal corpuscle, as a whole, forms a blood-filtering unit
- this allows water, metabolic wastes, ions, and small molecules to pass through the capillary wall but prevents circulating cells and large plasma protein from leaving blood
proximal convoluted tubules
- long tubes that follow a serpentine course os they drain the filtrate from the renal corpuscles into the loop of henle.
- each is lined by simple cuboidal epithelium with abundant long microvilli (brush border) bordering the lumen
- each proximal convoluted tubule connects to a renal corpuscle at its urinary pole
functions of the proximal convoluted tubules
-functions of actively transporting ions and reabsorbing water, glucose, amino acids, proteins, and vitamins from the filtrate
What does reabsorption and location to the glomerulus have to do with each other?
the farther from the glomerulus, the less that gets absorbed
Loop of Henle
- continuation of the proximal convoluted tubule.
- U shaped
- descending limb and ascending limb
descending loop of henle
- permeable to water, chlorine, and sodium ions
- reabsorb water and salts and reduce the volume of the filtrate that has passed through the proximal convoluted tubules
ascending limb of the loop of henle
- impermeable to water
- actively pumps chlorine and sodium ions from the tubes back into the medullary interstitium
distal convoluted tubulues
- lined by small, simple cuboidal epithelial cells which have NO BRUSH BORDER
- macula densa
- remove Na+ and add K+ to the filtrate if aldosterone stimulation is present
- also reabsorb bicarbonate ions and secrete ammonium to adjust the pH balance
macula densa
tightly packed group of cells within the distal convoluted tubule that sense and monitors ionic content nd water volume of the filtrate
the collecting system
-collecting tubules
-collecting ducts
-papillary ducts
-
collecting tubules and ducts and ADH
- have clear cytoplasm and distinct cell-to-cell boundaries
- these tubules become highly permeable to water under the influence of antidiuretic hormone (ADH).
- depending on ADH levels, the tubules passively diffuse a variable volume of water from their lumens into the medullary interstitium, thus increasing the concentration of urine
ureters
- 2 of them lie in the exztraperitoneal CT
- laterally positioned on each side of the vertebral column
- long, small tubules
- lined by transitional epithelium
- surrounded by a thin layer of smooth muscle and CT
ureters (drainage)
- superiorly they drain the renal pelvis
- inferiorly they empty into the bladder by penetrating it posterior wall
ureters wall
- much thinner than the bladder wall
- composed of mucosa, muscular, and adventitia
Urinary bladder
3 openings
- 2 for ureters
- one for emptying urine into the urethra
How do the muscles run in the bladder?
in different directions so they can squeeze
What does the urinary bladder wall consist of?
- mucosal, muscularis, and advetitia layers
- 3 layers of smooth muscle in the muscularis
What are the suprarenal glands surrounded by?
renal fascia
suprarenal cortex
secretes hormones
- mineral corticoids
- glucocorticoids
- small amount of sex hormones
mineral corticoids
- secreted by the suprarenal cortex
- concerned with the control of fluid and electrolyte balance
glucocorticoids
- secreted by the suprarenal cortex
- concerned with the control of metabolism of carbohydrates, fats, and proteins
sex hormones
- small amount secreted by suprarenal glands
- play a role in the prepubertal development of the sex organs
suprarenal medulla
secretes catecholamines
- epinephrine
- norepinephrine
Arteries supplying the suprarenal glands
- inferior phrenic artery
- aorta
- renal artery
vein of the suprarenal gland
- one vein
- emerges from the hilum of each gland and drains into the inferior vena cava on the right and into the renal vain on the left
preganglionic sympathetic fibers of the suprarenal glands
- derived from splanchnic nerves supply the glands
- most of the nerves end in the medulla of the gland
- white
- fastest in body
- synapse INSIDE the structure
- NO ganglion
- synapses in the medulla (could say that the medulla is a ganglion)
