Urinary System

Question 1

Function of urinary system:

Answer 1

1. get rid of toxic metabolic wastes, nitrogenous wastes like urea
2. regulate water, electrolyte, and acid-base balance
3. get rid of hormones and drugs

Hormones: erythropoietin will produce RBC, calcitrol will cause Ca2+ absorption

Question 2

Kidneys:

Answer 2

retroperitoneal, superior lobe of left kidney is at level of T12

adrenal glands rest superiorly

150 g

Question 3

Kidney surrounded by several tissue layers, from deepest to superficial:

Answer 3

fibrous capsule, perirenal fat, renal fascia, pararenal fat

Question 4

Fibrous capsule:

Answer 4

dense irregular CT (connective tissue) that covers outer surface of kidney

Question 5

Perinephric (perirenal) fat:

Answer 5

adipose providing cushioning

Question 6

Renal fascia:

Answer 6

dense irregular CT anchoring kidney to posterior abdominal wall

Question 7

Paranephric (pararenal) fat

Answer 7

adipose located between renal fascia and peritoneum

Question 8

Hilium:

Answer 8

slit in the concave medial border where vessels, nerves, and ureter connect, continuous with an internal space called the renal sinus

Question 9

Renal cortex:

Answer 9

outer zone, renal columns are extensions of cortex towards the sinus

Question 10

Renal medulla:

Answer 10

inner zone, renal pyramids are triangular structures where the base makes contact with the cortex at the corticomedullary junction

Question 11

Apex of renal pyramid is called ___

Answer 11

renal papilla

Question 12

Renal papilla project into a hollow funnel-shaped structure called ___

Answer 12

minor calyx

Question 13

The major calyces fuse to form ___

Answer 13

renal pelvis, with collects urine and transports it into the ureter

Question 14

Calyces and pelvis are lined with ____ epithelium

Answer 14

transitional

Question 15

Each kidney has ____ renal lobes

Answer 15

8 to 15

Question 16

Renal Circulation – Showing the Math

Answer 16

Question 17

Blood enters kidneys through ___

Answer 17

renal arteries

Question 18

Within the renal sinus, the renal
arteries branch into ___

Answer 18

segmental arteries

Question 19

Segmental arteries branch into ___

Answer 19

interlobar arteries, which travel to the renal columns

Question 20

At corticomedullary junction, interlobar arteries branch into

Answer 20

arcuate arteries

Question 21

Arcuate arteries give off branches
called ____

Answer 21

interlobular arteries, which radiate out to the cortex

Question 22

As interlobular arteries enter the kidney cortex, they extend small branches called ___

Answer 22

afferent arterioles

Question 23

An afferent arteriole enters a renal corpuscle and forms a tuft of capillaries called ____

Answer 23

glomerulus

Question 24

The remaining blood exits the glomerulus and the renal corpuscle via the ____

Answer 24

efferent arteriole

Question 25

Efferent arterioles branch into one of two capillary networks:

Answer 25

peritubular capillaries, vasa recta

Question 26

Peritubular capillaries:

Answer 26

surround the convoluted tubules and reside primary in the cortex

Question 27

Vasa recta:

Answer 27

associated mainly with the nephron loop and primarily reside in the medulla

Question 28

Peritubular capillaries and vasa recta drain into a network of veins, including (4):

Answer 28

The smallest veins are the interlobular veins Interlobular veins merge to form arcuate veins Arcuate veins merge to form the interlobar veins Interlobar veins merge in the renal sinus to form the renal vein in each kidney

Question 29

Renal circualation summary:

Answer 29

Question 30

Innervation of the kidney:

Answer 30

mass of sensory and autonomic fibers collectively called the RENAL PLEXUS

Question 31

Pain from kidneys is usually referred to dermatomes:

Answer 31

T10-T12

Question 32

Nephron:

Answer 32

functional filtration unit of the kidney, ~ 1.2 million nephrons in each kidney cortical and juxtamedullary types

Question 33

Cortical nephrons:

Answer 33

bulk resides in kidney cortex; account for about 85% of all nephrons

Question 34

Juxtamedullary nephrons:

Answer 34

renal corpuscle lies near corticomedullary junction, and their long nephron loop extends deep into the medulla; account for 15% of all nephrons

Question 35

Renal corpuscle:

Answer 35

filters blood plasma, glomerulus and glomerular capsule

Question 36

Renal tubule:

Answer 36

converts filtrate into urine, consists of PCT, nephron loop, DCT, and collecting duct

Question 37

Basic Steps in the Formation of Urine:

Answer 37

1) Glomerular filtration secretes a plasma-like filtrate of the blood 2) Tubular reabsorption removes useful solutes from the tubular fluid, returns them to the blood 3) Tubular secretion removes additional wastes from the blood, adds them to the tubular fluid 4) Water conservation removes water from the urine and returns it to blood; concentrates wastes

Question 38

Glomerular capsule (Bowman’s capsule):

Answer 38

epithelial capsule surrounding the glomerulus; made of two layers separated by capsular space * Visceral layer (contacting glomerulus) made of podocytes * Parietal layer made of simple squamous epithelium

Question 39

Filtration membrane diagram:

Answer 39

Question 40

Proximal Convoluted Tubule:

Answer 40

Begins at tubular pole of renal corpuscle * Walls composed of simple cuboidal epithelium with tall microvilli * Cells reabsorb almost all nutrients leaked through the filtration membrane * Reabsorbed nutrients and water enter peritubular capillaries and are returned to the general circulation

Question 41

Nephron Loop:

Answer 41

The nephron loop (loop of Henle) projects into the medulla and contains two parts: 1. Descending limb: Extends from the cortex into the medulla * Lined with simple cuboidal then simple squamous epithelia * Reabsorption of water 2. Ascending limb: Returns from medulla into cortex * Lined with simple squamous then simple cuboidal epithelia * Active transport of salts into the medulla

Question 42

Distal Convoluted Tubule:

Answer 42

Renal cortex and contacts the afferent arteriole wall at the vascular pole * It is lined with simple cuboidal epithelium (but microvilli are sparse and short) * Secretes K+ and H+ from peritubular capillaries into tubular fluid * Responds to ADH and aldosterone by altering reabsorption – ADH causes increased water reabsorption – Aldosterone causes increased sodium reabsorption

Question 43

Juxtaglomerular cells:

Answer 43

modified smooth muscle cells at afferent arteriole located at vascular pole of renal corpuscle *can release renin that increases blood pressure

Question 44

Macula densa:

Answer 44

group of modified epithelial cells in DCT that contact juxtaglomerular cells *monitor ion concentration in tubular fluid and can stimulate juxtaglomerular cells

Question 45

Mesangial cells:

Answer 45

sit between juxtaglomerular cells and arterioles *can contract and phagocytize filtered particles

Question 46

Collecting ducts:

Answer 46

* run through medulla toward renal papilla * lined by simple cuboidal and simple columnar * reabsorption of H2O * modify tubular fluid under influence of aldosterone and ADH (higher level may lead to Na+ and H2O)

Question 47

Once tubular fluid leaves collecting duct, it is __

Answer 47

urine

Question 48

Ureter:

Answer 48

tubes that extends 25 cm from kidney to bladder, has 3-layered wall

Question 49

Urinary bladder:

Answer 49

storage of urine, superior surface covered with peritoneum

Question 50

Detrusor muscle:

Answer 50

muscular layer of bladder wall

Question 51

Rugae:

Answer 51

wrinkles of mucosa

Question 52

Trigone:

Answer 52

triangular region on floor of bladder defined by two ureter inlets and one urethra outlet

Question 53

Four tunics form the wall of the urinary bladder: Mucosa

Answer 53

transitional epithelium that lines the internal surface of the bladder, rugae allows for further distension

Question 54

Four tunics form the wall of the urinary bladder: Submucosa

Answer 54

dense irregular connective tissue that supports urinary bladder wall

Question 55

Four tunics form the wall of the urinary bladder: Muscularis

Answer 55

* Three layers of smooth muscle collectively called the detrusor muscle * A thickened internal urethral sphincter is present at urethral opening

Question 56

Four tunics form the wall of the urinary bladder: Adventitia

Answer 56

outer layer of areolar connective tissue

Question 57

Nephroptosis (floating kidney) :

Answer 57

* kidney detaches and drifts inferiorly * too little body fat or prolonged vibration * can twist and kink the ureter which causes pain, obstructs urine flow, and may lead to hydronephrosis

Question 58

Renal agenesis:

Answer 58

* congenital and chromosomal abnormalities

Question 59

Supernumerary kidney:

Answer 59

*very rare * presence of third smaller kidney *functions normally but susceptible to infection * typically has own blood supply and ureter

Question 60

Horseshoe kidney:

Answer 60

* 1 in 600 * asymptomatic * kidneys fuse together during development * kidney susceptible to trauma and stone formation

Question 61

Renal calculus (kidney stone):

Answer 61

Causes include hypercalcemia, dehydration, pH imbalances, frequent urinary tract infections, or enlarged prostate gland causing urine retention Treatment includes stone dissolving drugs, often surgery, or lithotripsy –nonsurgical technique that pulverizes stones with ultrasound