Chapter 25: The urinary system

Question 1

Renin

Answer 1

regulation of blood pressure

Question 2

Erythropoietin

Answer 2

Regulation of RBC production

Question 3

Kidneys

Answer 3

major excretory organs

Question 4

Ureters

Answer 4

transport urine from kidneys to urinary bladder

Question 5

Urinary bladder

Answer 5

temporary storage reservoir for urine

Question 6

Urethra

Answer 6

Transports urine out of the body

Question 7

Blood and Nerve Supply of kidneys

Answer 7

• > Kidneys cleanse blood; adjust its composition
• > renal arteries deliver ~ 1/4 (1200 ml) of cardiac output to kidneys each minute
• > arterial flow into and venous flow out of kidneys follow similar paths
• > Nerve supply via sympathetic fibers from renal plexus

Question 8

Nephrons

Answer 8

Structural and functional units that form urine

two main parts: renal corpuscle and renal tubule

Question 9

Renal Corpuscle (two parts)

Answer 9

Glomerulus: Tuft of capillaries; fenestrated endothelium -> highly porous -> allows filtrate formation

Glomerular capsule (Bowman’s capsule): Cup-shaped, hollow structure surrounding glomerulus

Question 10

Three part of Renal Tubule

Answer 10

Proximal convouluted tubule: proximal-> closest to renal corpuscle

Nephron Loop

Distal convoluted tubule: Distal -> farthest from renal corpuscle

Question 11

Proximal convoluted tubule (renal tubule)

Answer 11

• > cuboidal cells with dense microvilli (brush border -> increases surface area
  • > functions in reabsorption and secretion
  • > confined to cortex

Question 12

Nephron loop (Renal tubule)

Answer 12

descending and ascending limbs
distal descending limb =descending thin limb; simple squamous epithelium
Thick ascending limb (cuboidal to columnar cells)

Question 13

Distal convoluted tubule (DCT) (renal tubule)

Answer 13

cuboidal cells with very few microvilli
functions more in secretion than reabsorption
confined to cortex

Question 14

Collecting duct

Answer 14

• > receive filtrate from many nephrons
• > run through medullary pyramids -> striped appearance
• > fuse together to deliver urine through papillae into minor calyces

Question 15

Cortical nephrons

Answer 15

85% of nephrons; almost entirely in cortex

Question 16

Juxtamedullary nephrons

Answer 16

Long nephron loops deeply invade medulla
Ascending limbs have thick and thin segments
Important in production of concentrated urine

Question 17

Renal tubule associated with two capillary beds

Answer 17

glomerulus

peritubular capillaries

Question 18

How much urine is created from the fluid we process daily?

Answer 18

1.5 liters. we produce 180 L daily

Question 19

Glomerular Filtration

Answer 19

produces cell and protein free filtrate

Question 20

Tubular Reabsorption

Answer 20

Selectively returns 99% of substances from filtrate to blood in renal tubules and collecting ducts

Question 21

Tubular secretion

Answer 21

selectively moves substances from blood to filtrate in renal tubules and collecting ducts

Question 22

Kidneys filter body’s entire plasma volume….

Answer 22

60 times each day; Consume 20-25% oxygen used by body at rest; produce urine from filtrate

Question 23

Glomerular Filtration

Answer 23

• > passive process
• > hydrostatic pressure forces fluids and solutes through filtration membrane
• > Porous membrane between blood and interior of flomerular capsule

Question 24

Net filtration

Answer 24

Outward pressure-inward pressure

55-(15+30)= 10 mmHg

Question 25

Glomerular Filtration Rate (GFR)

Answer 25

Volume of filtrate formed per minute by both kidneys (normal= 120-125 ml/min)

Question 26

Kidney Functions

Answer 26

Regulating total water volume and total solute concentration in water. Regulating ECF ion concentrations Ensuring long-term acid-base balance Removal of metabolic wastes, toxins and drugs Activation of vitamin D Gluconeogenesis during prolonged fasting

Question 27

The blood-filtering structure of the kidney is called the

Answer 27

glomerulus

Question 28

Which type of nephron plays an important role in producing concentrated urine?

Answer 28

Juxtamedullary Nephrons

Question 29

What type of response by the afferent arterioles would you expect if blood pressure increased?

Answer 29

The afferent arterioles would constrict

Question 30

What would be the effect on urine output if sodium channels in the tubule cells were inhibited?

Answer 30

The volume would increase