The Urinary System Flashcards
What are the four major components making up the urinary system?
The kidneys, the ureters, the bladder and the urethra
Blood is supplied to each kidney by which vessels?
The renal arteries which arise from the aorta
Which vessels drain the blood from each kidney?
One or more renal veins drain the blood from each kidney to the inferior vena cava
The kidneys have a principle function of maintaining which three things
maintaining water, electrolytes and acid base
What do the kidneys excrete
toxic metabolic waste products especially nitrogenous molecules such as urea and creatinine
The kidney is involved in the osmotic regulation of what?
Blood plasma
The kidney is involved in other functions including hormonal and metabolic functions, list three things that they synthesise/aid in synthesis
Renin, erythropoietin and vit D
What does the renin synthesis in the kidney help in
a mechanism to control blood pressure
What does the synthesis of erythropoietin in the kidneys aid in
promotes red blood cell formation
How is the kidney involved in vitamin D and absorption of calcium
Vit d which regulates calcium balance is converted to a biologically active form in the kidney
What is the site of entry and exit of the renal blood vessels and the ureter called?
The hilium
*Label this kidney homie
There ya go
Where do nephrons arise from and where do they go to
nephrons arise in the cortex, loop down into the medulla and return to the cortex
The renal medulla is made up of how many pyramids?
10-18 pyramids
What do the renal medulla project into?
Into calyces-papillae / renal papillae
The surface of the calyces-papillae/ renal papillae is the opening of what?
The collecting ducts
The base of the pyramid consists of 400-500 elongated parallel arrays of tubules called?
medullary rays - they penetrate the cortex
What does each medullary ray consist of?
Straight collecting ducts surrounded by tubular portions of the nephron
What is the functional unit of the kidney?
The nephron
*Label this diagram of the functional unit of the kidney
there ya go
How many nephrons are there
1-4 million filtering units
What does the nephron consist of
the renal corpuscle, the proximal convoluted tubule, the loop of henle and the distal convoluted tubule , collecting duct
What is the renal corpuscle?
a tuft of capillaries, the glomerulus as well as the urinary poles, the afferent and efferent vessels, etc
who discovered the renal corpuscle?
sir william bowman - a surgeon 1816-1892
*Label this image of the renal corpuscle
there ya go
What are the two poles on the renal corpuscle
the urinary pole and the vascular pole
what may the glomerulus and bowman’s capsule sometimes be referred to as
the malpighian body
What two layers are present on the Bowman’s capsule
the visceral and parietal layer
*label the visceral and parietal layer of the Bowman’s capsule
there ya go
The visceral layer of the bowmans capsule is modified during embryological development to form what?
Podocytes
What are podocytes?
specialised cells with primary and secondary processes - foot processes
what is special about the endothelium of the glomerulus cells
a fenestrated endothelium exists
what are mesangial cells in the glomerulus?
they are supporting cells for the capillaries that produce mesangial matrix
What does the proximal convoluted tubule look like in comparison to the distal tubule
it is longer and larger than the distal tubule
What cells line the proximal convoluted tubule?
simple cuboidal
why do cells of the proximal convoluted tubule deeply eosinophilic
because they have many mitochondria
Why do cells of the proximal convoluted tubule have a brush border when viewed under the microscope
because they have microvilli AND THE DISTAL ONES DO NOT
What is the function of the proximal convoluted tubule?
active absorption of peptides and glucose as well as ion exchange
how would you describe the distal convoluted tubule?
the last segment of the nephron
What type of epithelium lines the distal convoluted tubule?
Simple cuboidal epithelium
How would you explain the distal convoluted tubule in terms of brush borders and eosiophilic appearance
no brush border and lacks eosinophilic appearance because there arent as many mitochondria - not as active
Eosinophilic staining of a structure means
Eosin is pink in color and is an acidic dye (negatively charged) that binds to positively charged particles like the mitochondria and many components of the cytoplasm.
Urine passes from the distal convoluted tubule to which structure
to the collecting ducts
Collecting ducts join each other to form larger straight ducts called
papillary ducts of Bellini
Who discovered the papillary ducts of Bellini?
Lorenzo bellini
what is the main function of the loop of henle
to create a concentration gradient in the medulla of the kidney
What system does the loop of henle use in order to create a concentration gradient in the medulla
the countercurrent multiplier system
How does the loop of henle create a concentration gradient
by utilising the sodium pumps to create an area of high sodium conc deep in the medulla near the collecting duct
how does water present in the filtrate in the collecting duct flow out of the collecting duct?
through aquaporin channels moving passively down its concentration gradient
The process of the countercurrent multiplier system does what
it reabsorbs water and creates a concentrated urine for excretion
the absorptive capacity of the collecting duct is controlled by what
ADH- antidiuretic hormone
What will a lack of adh in the collecting duct lead to
lack of adh will lead to a lack of absoprtion of water so production of dilute urine
what will a release of adh into the collecting duct result in
release of adh makes collecting duct permeable to water and this is then absorbed passively into the hypertonic medulla leading to production progressively more concentrated urine
