Snf Test 4 - Urinary System

Front 1

What are the components of the urinary system?

Back 1

Kidneys
Ureters
Urinary bladder
Urethra

Front 2

What are the functions of the kidneys?

Back 2

Excretion of detoxified substances (e.g. drug metabolism)
Regulation of body fluid composition and volume (solute components)
Regulates urine osmolality
Secretes erythropoietin, renin, angiotensin I, medullipin I, prostaglandins
Regulates blood pressure
Aids in conversion of Vitamin D to dihydroxycholecalciferol (Ca2_ transport protein)

Front 3

What is the shape of the kidney?

Back 3

Large, red, bean-shaped, retroperitoneal
Posterior abdominal wall
Right is 1-2 cm lower than left (why?)
11 cm long, 4-5 cm wide, 2-3 cm thick
Hilus faces midline (medial); renal artery and vein, ureter, lymph vessels; renal pelvis
Covered by capsule and surrounded by fat w/ adrenal glands embedded in fat at superior poles

Front 4

What are the physical aspects of the cortex of the kidney?

Back 4

Brown and granular

Front 5

What are the physical aspects of the medulla of the kidney?

Back 5

6-12 pale, striated renal pyramids with base toward cortex and apex toward hilus
Apex perforated by ducts of Beillini (area cribosa) which forms minor calyx. 2-3 minor calyces drain into major calyces. 3-4 major calyces drain into renal pelvis.
Pyramids are separated by cortical columns of Bertin

Front 6

What is found in the renal cortex?

Back 6

Renal corpuscles
Cortical labyrinth (convoluted tubules)
Medullary rays (cortical continuations of material from pyramids)
Lobe - renal pyramid with arch + cortical columns
Lobule - medullary ray with part of cortical labyrinth surrounding it

Front 7

What is the uriniferous tubule?

Back 7

Unit of structure and function
Consists of two components:
1. Nephron (1-3 million per kidney): densely packed, scant stroma, mainly intervening basal lamina of epithelium
2. Collecting duct: several nephrons are drained by a single collecting duct. Ducts converge to evenutally form terminal ducts of Bellini.

Front 8

What is a nephron?

Back 8

Two groups/types:
1. Cortical
2. Juxtamedullary (15%, 40mm in length)
Components:
-Renal corpuscle
-Complex tubular system

Front 9

What are the shape, size and portions of the renal corpuscle?

Back 9

Shape - oval to round
Size - 200-250 microns in diameter
Two portions:
1. Glomerulus - capillary tuft
2. Bowman's capsule - visceral (podocytes) and parietal (simple squamous) layers
Vascular pole - afferent and efferent arterioles
Urinary pole - connections w/ proximal tubule

Front 10

What are the characteristics of the filtration barrier found in the Urinary System?

Back 10

-Glomerular capillary endothelium
-Basal lamina of endothelium and visceral layer of Bowman's capsule (podocytes)
-Visceral layer of Bowman's capsue
-Connective tissue - mesangial cells
1. Extraglomerular - at vascular pole
2. Intraglomerular - within the renal corpuscle

Front 11

What are the characteristics of the capillaries of the filtration barrier?

Back 11

-Fenestrated
-Pores do not have diaphragms
-Pores are large - 70-90nm and only exclude formed elements of blood and proteins larger than 69,000 daltons
-Attenuated epithelium

Front 12

What are the functions of the intraglomerular mesangial cells?

Back 12

-Phagocytic - clear basal lamina of proteins and other large molecules trapped by basal lamina

-Contractile - have receptors for angiotensin II which causes vasoconstriction and thus reduces blood flow

Front 13

What are the characteristics of Bowman's Capsule (Podocytes)?

Back 13

Have primary precesses that have secondary processes (pedicels) which are applied to the glomerular capillaries.

Filtration slits with slit diaphragms (6nm complex circular pores)

Front 14

What does the filtration barrier do?

Back 14

-Responsible for the formation of the glomerular filtrate
-Kidneys receive 20% of total blood volume each minute (1220ml/min) and manufactures 1-2 ml urine/min
-1220 ml/min yields 125 ml glomerular filtrate/min
-180 L/day yields 1.5-2L urine/day - 128L recovered/1% excreted

Front 15

What are the components of the proximal tubule?

Back 15

-Pars convoluta (convoluted portion)
-Pars recta (straight portion - descending thick limb of Henle)

Front 16

What are the components of the limbs and loop of Henle?

Back 16

-Thin descending limb, loop, ascending thin limb

Front 17

What are the components of the distal tubule?

Back 17

-Pars recta (straight portion - ascending thick limb)
-Macula densa (junction of p. recta and p. convoluta)
-Pars convoluta (convoluted portion)

Front 18

What is the histology of the proximal tubule?

Back 18

-Simple cuboidal epithelium with eosinophilic and granular appearing cytoplasm
-Elaborate striated border
-Intricate lateral processes

Front 19

What are the functions of the proximal tubule?

Back 19

- Recovers 67-80% of Na+, Cl-, H2O
- Recovers all of glucose, amino acids, and proteins
- Eliminates organic solutes, drugs, and toxins

Front 20

What is the histology of the Henle complex and what does each limb do?

Back 20

-Squamous epithelium
-Descending limb: Premeable to water, urea, sodium, chloride, and other ions
-Ascending limb: Only moderately permeable to water

Front 21

What are the characteristics of the pars recta (ascending portion) of the distal tubule?

Back 21

-Impermeable to water or urea
-Possesses a chloride (an possibly a sodium) pump that actively transports chloride (and possibly sodium) from lumen

Front 22

What are the characteristics of the pars convoluta of the distal tubule?

Back 22

-Impermeable to water and urea
-Basal Na+/K+/ATPase powered sodium-potassium exchange pump

Front 23

What is the macula densa?

Back 23

Junction between the pars recta (ascending portion) and pars convoluta of the distal tubule.

Front 24

How does aldosterone affect the distal tubule?

Back 24

-Causes distal tubule to actively reabsorb remaining sodium (and chloride, passively)
-K+ and H+ ions are secreted controlling extracellular fluid K+ and acidity of urine respectively

Front 25

What are the characteristics of the juxtaglomerular (J-G) cells of the afferent arterioles?

Back 25

-Modified smooth muscle cells of the afferent arteriole
-Possess granules which contain renin
-Also contain angiotensin-converting enzyme (ACE), angiotensin I, and angiotensin II

Front 26

What are the components of the Juxtaglomerular apparatus?

Back 26

1. Macula densa of the distal tubule
2. Juxtaglomerular (J-G) cells of afferent arteriole
3. Extraglomerular mesangial cells

Front 27

Do the cells of the macula densa of the distal tubule and afferent arteriole have a basal lamina?

Back 27

No, cells in direct contact

Front 28

What are the characteristics of the collecting tubules?

Back 28

-Predominantly conduits
-3 major divisions:
1. Cortical
2. Medullary
3. Papillary

Front 29

What are the two major cell types of the cortical collecting ducts?

Back 29

1. Principal
2. Intercalated: can actively transport and secrete H+, thus modulating acid-base balance

Front 30

Are the cells of the cortical collecting ducts normally permeable to water?

What causes permeability to water (and urea)?

Back 30

No

ADH - causes permeability to water (and urea)

Front 31

What happens if you increase ADH?

Back 31

Decreases urinary volume and concentrates urine

Front 32

What happens if you decrease ADH?

Back 32

Copious urine volume, hypotonic (dilute)

Front 33

What is found in the intraglomerular mesangium?

Back 33

Fibroblasts
Macrophages
Interstitial cells - synthesize medullipin I which is converted to medullipin II in the liver resulting in vasodilation (and thus decreases blood pressure)

Front 34

Where does the renal artery branch form and what are its characteristics?

Back 34

Branches from the abdominal artery
Renal artery has 5 segmental arteries (no anastomoses) - there are also lobar arteries 1 for each lobe

Front 35

What is the vascular pathway of renal circulation?

Back 35

-2-3 interlobular arteries (between pyramids to cortico-medullary junction)
-Arcuate arteries (arc over base of renal pyramids)
-Interlobular arteries (between neighboring medullary rays)
-Afferent glomerular arteriole
-Glomerulus
-Efferent glomerular arteriole
-Peritubular capillary network (cortical labyrinth)
-Vasa recta of loop

Front 36

Where do the vasa recta, stellate (subcapsular) veins and efferent arterioles and interlobular veins go?

Back 36

Arcuate vein --> Interlobar vein --> Renal vein