Urinary System

Question 1

What are the components of the urinary system?

Answer 1

Kidneys
Ureters-conduct urine from kidneys to bladder
Urinary bladder-distensible reservoir for urine
Urethra-fibromuscular tube conveys urine from bladder to exterior

Question 2

What are the functions of the kidneys?

Answer 2

Remove metabolic waste
Conserve body fluid, produce urine
Regulate pH and blood pressure
Endocrine organ that produce erythropoietin and renin

Question 3

What are the parts of the kidney macrostructure?

Answer 3

Capsule formed by DICT made by collagen fibers, fibroblasts and myofibroblasts
Renal calyces consisting of minor and major calyces lined with transitional epithelium,no more change in urine
Renal pelvis larfer reservoir open into ureter
Hilum

Question 4

What are the 2 parts of the kidney substance?

Answer 4

Cortex-external part- in fresh specimen more red than medulla
Medulla- Internal part

Question 5

What are the parts of the kidney cortex?

Answer 5

Renal corpuscles only found in cortex
Renal tubules
Renal columns found between pyramids of medulla

Question 6

What are the components of the renal tubules?

Answer 6

Cortical labyrinth made of convoluted tubules

Medullary rays formed by straight tubules and collecting dusts

Question 7

What are the components of the medulla?

Answer 7

Pyramids (8-12) formed by the renal tubules
Papilla-tip of the pyramid formed by the perforated plate called the area cribosa where collecting ducts empty into minor calyces

Question 8

What are the divisions of the medulla?

Answer 8

Outer medulla made of thick and thin tubules. Consists of 2 parts:
The outer stripe -only thick tubules present
The inner stripe- both thick and thin tubules present
Inner medulla made of only thin tubules

Question 9

What is the nephron?

Answer 9

Functional unit of kidney.Consists of:
renal corpuscles
renal tubules with unclear lateral sides
Each nephron is unbranched
Several nephrons empty into a collecting tubule via connecting tubule

Question 10

What are the characteristics of the renal corpuscle?

Answer 10

Spherical structure whose major function is filtration of blood
Consists of glomerulus surrounded by Bowman’s capsule

Question 11

What are the characteristics of the Bowman’s capsule?

Answer 11

2 layers providing entry and exit for blood vessels and renal tubules
Parietal layer is a simple squamous epithelium
Visceral layer is formed by modified epithelial cells with processes called podocytes
Between the 2 layers is the urinary space

Question 12

What are the processes of the podocytes?

Answer 12

Primary processes-larger
Secondary processes or pedicels envelop glomerular capillaries by interdigitating and leaving small gaps called filtration slits
Slit diaphragm is a negatively charged barrier located at the base of the filtration slits and formed by component of glycocalyx of adjacent cells

Question 13

What is the vascular pole?

Answer 13

Area of Bowman’s capsule where blood vessels enter and exit corpuscle

Question 14

What is the urinary pole?

Answer 14

Area of Bowman’s capsule where proximal convolute tubule draining urinary space originates

Question 15

What are the characteristics of the glomerulus?

Answer 15

Cluster of fenestrated capillaries without diaphragm and a single basal lamina
Mesangial cells located at the end of capillaries

Question 16

What are the functions of the mesangial cells?

Answer 16

Control glomerular flow
Possess angiotensin 2 receptors causing a reduction in blood flow
Structural support for glomerulus
Phagocytose of residue and protein trapped on basal lamina

Question 17

What are the different kidney tubules?

Answer 17

Proximal convoluted tubule (PCT)
Loop of Henle subdivided into 4 parts: thick and thin descending limbs and thin and thick ascending limbs
Distal convoluted tubule (DCT)
Connecting tubules
Collecting tubules

Question 18

What are the characteristics of the PCT?

Answer 18

Formed by large cuboidal cells with well developed microvilli forming a brush border
Tight and adherens junctions seal the apical border
Basal striations are formed by mitochondria
Function in reabsorption of AA, proteins and ions
Ultrafiltrate is isotonic to plasma

Question 19

What are the characteristics of the thick descending limb of the loop of Henle?

Answer 19

Also called proximal straight tubule is shorter and lined with simple cuboidal epithelium
It is similar to PCT
Present only in the outer stripe of the outer medulla

Question 20

What are the characteristics of the thin descending limb of the loop of Henle?

Answer 20

Lined with simple squamous epithelium
Highly permeable to water
Sodium chloride and urea enter filtrate leading to hyperosmotic fluid
Found in inner stripe of outer medulla and inner medulla

Question 21

What are the characteristics of the thin ascending limb of the loop of Henle?

Answer 21

Lined with simple squamous epithelium
Impermeable for water
Highly permeable to sodium chloride leading to hypotonic filtrate
Only present in the inner medulla

Question 22

What are the characteristics of the thick ascending limb of the loop of Henle?

Answer 22

Also called distal straight tubule
Lined with simple cuboidal epithelium
Similar to DCT
Impermeable to water and urea
Transport sodium and chloride ions from lumen to interstitium leading to more hypotonic filtrate compare to thin ascending limb
Forms macula densa
Long runs from inner stripe of the outer medulla through the outer stripe into cortex

Question 23

What are the characteristics of the DCT?

Answer 23

Formed by cuboidal cells
No brush border present
Has a prominent basal striations formed by mitochondria
Function in reabsorption of sodium, chloride and bicarbonate ions

Question 24

What are the characteristics of the connecting tubule?

Answer 24

Connects DCT to the collecting duct

Lined with simple cuboidal epithelium

Question 25

What are the characteristics of the collecting duct?

Answer 25

Lined with simple cuboidal epithelium made of 2 types of cells: Principal cells-main type with no interdigitating lateral membranes Intercalated cells-regulate pH by transporting hydrogen and bicarbonate ions in and out of cells

Question 26

What are the functions of the principal cells?

Answer 26

Respond to vasopressin (ADH) | Open water channels decreasing urine volume and increasing urine concentration and blood pressure

Question 27

What are the different types of collecting ducts?

Answer 27

Cortical collecting ducts in medullary rays of cortex Medullary collecting ducts in medulla Papillary collecting ducts emptying into minor calyces

Question 28

What is the osmolarity of the ultrafiltrate through the nephron?

Answer 28

``` Isotonic- Thick descending limb Hyperosmotic- Thin descending limb Hypo osmotic- thin and thick ascending limbs and collecting duct Hyperosmotic- Medullary interstitium Isotonic- Cortical interstitium ```

Question 29

What are the types of nephrons?

Answer 29

Juxtamedullary nephrons | Cortical nephrons

Question 30

What are the characteristics of the juxtamedullary nephrons?

Answer 30

Renal corpuscles closer to medulla | Long loops of Henle with both descending and ascending thin limbs

Question 31

What are the characteristics of the cortical nephrons?

Answer 31

Renal corpuscles closer to the capsule Short loops of Henle with only thin descending limb No thin ascending limb

Question 32

What are the components of the juxtaglomerular apparatus?

Answer 32

Macula densa Juxtaglomerular cells Extraglomerular mesangial cells

Question 33

What are the characteristics of the macula densa?

Answer 33

Formed by modified epithelium of the thick ascending limb of the loop of Henle major function is to sense the chloride concentration in the tubule

Question 34

What are the characteristics of the juxtaglomerular cells?

Answer 34

Modified smooth muscle cells | Release renin through its secretory granules

Question 35

What are the characteristics of the extraglomerular mesangial cells?

Answer 35

Located in the cleft between macula densa and the afferent and efferent arterioles Provide structural support and transmit signals from macula densa to juxtaglomerular cells

Question 36

What are the characteristics of the arterial supply of the kidneys?

Answer 36

Kidneys receive blood supply via renal arteries which break into smaller arteries: segmental and lobar arteries Interlobar arteries are branches of the lobar arteries and travel between the pyramids give off arcuate arteries Arcuate arteries mark the boundary between the cortex and medulla Interlobular arteries run perpendicular to arcuate and give off afferent arteriole which supplies glomerulus Efferent arterioles drain capillaries of glomerulus and give rise to second capillary bed Peritubular capillaries for cortical nephrons Vasa recta for juxtamedullary nephrons

Question 37

What are the characteristics of the venous drainage of the kidney?

Answer 37

Peritubular capillaries drain into interlobular or stellate veins Stellate veins drain into interlobular veins Ascending vasa recta drain into arcuate veins tributaries of interlobar veins and accompany the arcuate arteries Interlobar veins unite to form renal vein

Question 38

What are the characteristics of the ureter?

Answer 38

Lining is formed by transitional epithelium Muscularis is fromed by 3 layers of smooth muscle (inner and outer longitudinal and middle circular) Adventitia is made of adipose tissue, CT and nerves

Question 39

What are the characteristics of urinary bladder?

Answer 39

Lining is transitional epithelium Has a thick muscularis and forms detrusor muscle Has serosa(upper part) and adventitia

Question 40

What are the characteristics of transitional cell carcinoma?

Answer 40

Common epithelial malignant tumor and agressive | Occurring in kidney pelvis, ureter and bladder

Question 41

What are the parts of the male urethra?

Answer 41

Prostatic-transitional epithelium, ejaculatory ducts open @ the beginning Membranous-columnar epithelium, pseudostratified/stratified- external urethral sphincter made of skeletal muscle Penile-pseudostratified columnar, stratified squamous, (glands of Littre)

Question 42

What are the characteristics of the female urethra?

Answer 42

Short Lined with transitional, pseudo columnar and stratified columnar External sphincter is made of striated voluntary muscles