Topic 16: Urinary System

Question 1

what are the structures of the urinary system?

Answer 1

-2 kidneys
-2 ureters
-1 urinary bladder
-1 urethra

Question 2

what are the functions of the urinary system?

Answer 2

-regulates
-eliminates

Question 3

what does the urinary system regulate?

Answer 3

-blood volume + pressure
-pH (H+ and HCO3-)
-ion concentrations (Na+, Ca++, K+, Cl-)
-secretion of renal hormones

Question 4

how does the urinary system regulate blood volume + pressure?

Answer 4

-more fluid=more pressure
-releases more fluids to regulate

Question 5

what wastes does the urinary system eliminate?

Answer 5

-urea (waste)
-uric acid (waste)
-hormones
-drugs (antibiotics)
-toxins

Question 6

what are the characteristics of the kidenys?

Answer 6

-retroperitoneal
-right is lower than the left
-supported + protected by 3 layers of CT

Question 7

what are the 3 supporting CT layers of the kidney?

Answer 7

-fibrous capsule (outer)
-perirenal fat capsule (middle)
-renal fascia (inner)

Question 8

what is the renal hilus?

Answer 8

-also called the hilum
-medial indentation
-entry point of multiple things

Question 9

what is the renal hilus the entry point of?

Answer 9

-renal artery (superior)
-renal vein (inferior)
-ureter
-nerves

Question 10

what is the internal anatomy of the kidneys?

Answer 10

-renal cortex (superficial)
-renal medulla
-renal pelvis

Question 11

what is contained in the renal medulla?

Answer 11

-renal pyramids
-renal columns

Question 12

what are the renal pyramids?

Answer 12

-contain parts of nephrons
-apex of the pyramid = renal papilla (to release filtrate)

Question 13

what is the renal cortex?

Answer 13

-superficial layer
-contains parts of nephrons
-contains afferent and efferent arterioles
-contains capillary beds (glomeruli)

Question 14

what are the renal columns?

Answer 14

-projections of the cortex into the medulla
-separate renal pyramids
-contain arteries, veins, and nerves that supply the cortex

Question 15

what is a nephron? what is it composed of?

Answer 15

-functional unit of the kidney
-composed of the renal corpuscle and renal tubules

Question 16

what is the renal corpuscle?

Answer 16

-in the cortex
-site of blood filtration
-is formed by the glomerulus, glomerular (bowman’s) capsule, afferent and efferent arterioles, and the filtration membrane

Question 17

what is the glomerulus?

Answer 17

-capillary bed
-very leaky capillaries
-simple squamous (endothelium) with many pores (fenestrations) between cells

Question 18

what is the glomerular (bowman’s) capsule?

Answer 18

-surrounds the glomerulus
-collects filtrate from the glomerulus
-has an outer and inner layer

Question 19

what is the outer layer of the bowman’s capsule? why?

Answer 19

-simple squamous epithelium

Question 20

what is the inner layer of the bowman’s capsule?

Answer 20

-cells called podocytes that wrap around glomerular capillaries

Question 21

what are podocytes?

Answer 21

-cells that have many finger-like projections
-form a network of filtration slits

Question 22

what is the filtration membrane?

Answer 22

-glomerular endothelium (capillaries)
-shared basement membrane (between the other 2)
-podocytes

Question 23

what are the four parts of the renal tubule

Answer 23

-proximal convoluted tubule (PCT)
-nephron loop
-Distal Convoluted Tubule (DCT)
-Collecting Ducts

Question 24

where is the PCT located? what type of tissue is it composed of? what is its function?

Answer 24

-in the cortex
-cuboidal epithelium with dense microvilli
-receives filtrate from the glomerular capsule
-reabsorbs most useful substances from the filtrate (glucose + amino acids)
-secretes waste products into the filtrate

Question 25

where is the nephron loop located? what forms it?

Answer 25

-in the medulla -descending limb (thin, simple squamous epithelium) -ascending limb (thick, simple cuboidal epithelium)

Question 26

where is the DCT located? what tissue forms it?

Answer 26

-in the cortex -cuboidal epithelium

Question 27

where are the collecting ducts located? what is their purpose?

Answer 27

-in the cortex + medulla -drains filtrate from numerous nephrons into minor calyces -contains cells that regulate water and Na+ reabsorption and acid/base balance of the blood

Question 28

what are the 2 types of nephrons?

Answer 28

-cortical (majority) -juxtamedullary (small amount)

Question 29

what is special about cortical nephrons?

Answer 29

-renal corpuscles are near the kidney surface in the cortex -short nephron loop (dips in the outer medulla) -has peritubular capillaries that branch from the efferent arteriole and surround the DCT + PCT

Question 29

what is the purpose of the juxtaglomerular complex?

Answer 29

-regulates filtrate formation (amount of salts + ions being removed) -point of contact between the ascending limb, afferent + efferent arterioles at the renal corpuscle of the same nephron

Question 29

what is special about juxtamedullary nephrons?

Answer 29

-renal corpuscles in the cortex near the medulla -long nephron loops -loops penetrate deep in the medulla -has capillaries called vasa recta that branch from efferent arterioles and run parallel to the nephron loop

Question 30

what are the two parts of the juxtaglomerular complex?

Answer 30

-tubular portion (macula densa) -vascular (arteriolar) portion

Question 31

what is the tubular portion of the juxtaglomerular complex?

Answer 31

-modified (tall + narrow) DCT cells -monitors filtrate composition

Question 32

what is the vascular (arteriolar) portion of the juxtaglomerular complex?

Answer 32

-afferent + efferent arteriole portion -granular (juxtaglomerular cells) -modified smooth muscle cells that monitor blood pressure -secrete an enzyme/hormone that helps to regulate blood pressure and ion balance

Question 33

what are retroperitoneal parts of the urinary system?

Answer 33

-kidneys -ureters -urinary bladder

Question 34

what type of epithelium is the mucosa of the ureters?

Answer 34

-transitional epithelium (stretching)

Question 35

do the ureters have a submucosa layer?

Answer 35

-no -lamina propria is connected directly to the muscularis externa

Question 36

what is the muscularis externa layer of the ureters?

Answer 36

-smooth muscle -amount is dependent on location

Question 37

do the ureters have an adventitia or a serosa?

Answer 37

-adventitia -retroperitoneal -connects ureter to the body wall

Question 38

what type of epithelium is the mucosa layer of the urinary bladder?

Answer 38

-transitional epithelium with rugae (for stretching)

Question 39

does the urinary bladder have a submucosa layer?

Answer 39

-no submucosa -lamina propria is directly connected to the muscularis externa

Question 40

what is the muscle called in the muscularis externa layer of the urinary bladder? what does the contraction of this muscle cause?

Answer 40

-detrusor muscle (smooth muscle) -contraction causes urination

Question 41

does the urinary bladder have serosa or adventitia?

Answer 41

-mostly adventitia -serosa covers the superior surface

Question 42

what are the 2 sphincters of the urethra? what do they surround?

Answer 42

-internal urethral sphincter -external urethral sphincter -the proximal end of the urethra

Question 43

what is the internal urethral sphincter?

Answer 43

-thickening of detrusor muscle at the base of the bladder -smooth muscle (involuntary)

Question 44

what is the external urethral sphincter?

Answer 44

-in the urogenital diaphragm -skeletal muscle (voluntary)

Question 45

what does the urethra transport in females?

Answer 45

-transports urine

Question 46

what does the urethra transport in males?

Answer 46

-transports urine + semen

Question 47

how does the glomerular endothelium create the filtration membrane?

Answer 47

-fenestrations allow plasma through, but not formed elements or most large proteins

Question 48

what is the role of the efferent arteriole in the nephron?

Answer 48

-exits the glomerulus -drains into the peritubular (cortical nephrons) -drains into the vasa recta (juxtaglomerular nephrons)

Question 49

what is the role of the afferent arteriole in the nephron?

Answer 49

-enters the glomerulus -carries blood delivered to the kidney from the renal artery

Question 50

which parts of the nephron loop are water permeable/impermeable?

Answer 50

-descending = water permeable -ascending = water impermeable

Question 51

what do the long nephron loops of the juxtamedullary nephrons allow for?

Answer 51

-allows for different concentrations of urine depending on the need -ex: conserving water for blood pressure and volume

Question 52

what is the purpose of the ureters?

Answer 52

-transports urine from the renal pelvis to the bladder

Question 53

what are the 3 histology layers of the ureters?

Answer 53

-mucosa -muscularis externa -adventitia

Question 54

what is the purpose of the urinary bladder?

Answer 54

-short term storage for urine

Question 55

what are the 3 histology layers of the urinary bladder?

Answer 55

-mucosa -muscularis externa -adventitia/serosa

Question 56

what is the purpose of the urethra?

Answer 56

-drains urine from the urinary bladder

Question 57

what are the 3 histology layers of the urethra?

Answer 57

-mucosa -muscularis externa (smooth muscle) -adventitia

Question 58

what is the mucosa of the urethra?

Answer 58

-transitions from transition epithelium to stratified squamous epithelium

Question 59

what is the filtrate/urine pathway?

Answer 59

-several DCT -collecting ducts (exit at the renal papilla) -minor calyx -major calyx -renal pelvis -ureter -urinary bladder -urethra