Renal System Part 1

Question 1

Kidneys

Answer 1

Produce urine

Question 2

Ureters

Answer 2

Transports urine from the kidneys to the urinary bladder

Question 3

Urinary bladder

Answer 3

Temporarily stores urine prior to elimination

Question 4

Urethra

Answer 4

Conducts urine to exterior

Question 5

Functions of Urinary System

Answer 5

1. Storage of urine
2. Expulsion of urine
3. Regulation of blood volume via hormones
4. Regulation of erythrocyte # via erythropoietin (EPO)
5. Regulation of ion levels (sodium, potassium, calcium, phosphate)
6. Regulation of acid-base balance (hydrogen and bicarbonate ions)

Question 6

Renal cortex

Answer 6

-Superficial region of kidney
-Contains nephrons

Question 7

Renal medulla

Answer 7

-Deep to cortex
-Has renal pyramids
-Urine collecting tubes

Question 8

Renal papilla

Answer 8

Apex of renal pyramid

The connection of the tip of the medulla and the calyx (which is where urine drains into the ureters).

Question 9

Minor calyx vs major calyx

Answer 9

1) Collects urine from renal papilla

2) Formed by fusion of several
minor calyces

Question 10

Renal pelvis

Answer 10

Continuous with ureter. Walls have smooth muscle to move urine.

Question 11

Nephron

Answer 11

Functional unit of the kidney

Made of renal corpuscle and renal tubule

Question 12

Cortical nephron

Answer 12

• 85% of all nephrons
• Located primarily in the cortex
• Loop of Henle is relatively short
• Most regulatory functions

Question 13

Juxtamedullary nephron

Answer 13

• 15% of nephrons
• Long loop of Henle extending
  deep into medulla
• Essential to producing
  concentrated urine

Question 14

Renal corpuscle

Answer 14

Glomerulus: A network of capillaries where blood is filtered.

Bowman’s Capsule: A cup-like structure that surrounds the glomerulus and collects the filtered fluid (filtrate).

Question 15

Glomerulus

Answer 15

Tuft of capillaries associated with renal tubule

Each glomerulus is supplied with blood by an afferent arteriole and drained by an efferent arteriole.

Question 16

Bowman’s (Glomerular) capsule

Answer 16

-Blind, enlarged, cup-shaped structure
-Surrounds glomerulus

Question 17

Renal tubule

Answer 17

Proximal Convoluted Tubule (PCT):
Located in the cortex, this tubule reabsorbs essential substances like water, glucose, and amino acids from the filtrate.

Loop of Henle: A hairpin-shaped structure that extends into the medulla, responsible for establishing a concentration gradient in the kidney. It has a thin descending limb (permeable to water) and a thin ascending limb (permeable to solutes).

Distal Convoluted Tubule (DCT):
Located in the cortex, this tubule further modifies the filtrate, reabsorbing water and electrolytes under hormonal control.

Collecting Duct: A structure that collects fluid from multiple nephrons and transports it to the renal pelvis, where it becomes urine.

Juxtaglomerular Apparatus: A specialized structure involved in regulating blood pressure and fluid balance.

Question 18

Filtration

Answer 18

Occurs in renal corpuscle. Provides both permeability and selectivity.

Question 19

Glomerular Filtration

Answer 19

Passive process: hydrostatic pressures force the fluids and solute through a membrane.

Efficient filter because:

1. Filtration membrane has a large surface area and is very permeable to water & solutes
2. Glomerular pressure is higher, so they produce more filtrate

180 L/day (glomerulus) vs. 3-4 L/day (other capillary beds)

Plasma proteins (like albumin) stay in the blood because they are too large to pass through the filtration membrane. These proteins create an osmotic pressure — they pull water back into the blood to oppose some of the outward filtration pressure. This helps prevent excessive loss of water from the blood.

Question 20

Proteinuria

Answer 20

Blood cells or protein in the urine

Problem with the filtration membrane= renal failure

Common where kidney damage has occurred (Ex: Diabetes, hypertension, etc.)

Question 21

Glomerular Filtration Rate (GFR)

Answer 21

Volume of filtrate formed each minute ~ 125 mL/min

GFR is directly proportional to the NFP

Without regulation - ↑ BP =↑ GFR

Question 22

GFR is affected by:

Answer 22

1. Surface area available for filtration
2. Filtration membrane permeability
3. Net filtration pressure (NFP)
4. Blood pressure / blood flow to the glomerular capillaries

Question 23

Vascular Changes Control GFR

Answer 23

Constriction of afferent arteriole/dilation of efferent arteriole= decreased GFR (and vice versa)

Question 24

Glomerular Hydrostatic Pressure

Answer 24

Outward

Glomerular hydrostatic pressure (GHP) is the pressure exerted by the blood within the glomerular capillaries, forcing fluid and solutes out into the Bowman’s capsule. This pressure is a key driver of glomerular filtration.

Question 25

Blood Colloid Osmotic Pressure

Answer 25

Inward Blood colloid osmotic pressure (BCOP) is the pressure exerted by proteins in the blood plasma that draws water back into the blood vessels.

Question 26

Capsular Hydrostatic Pressure

Answer 26

Inward Capsular hydrostatic pressure (CHP) is the pressure exerted by fluid within Bowman's capsule against the filtration membrane in the kidneys.

Question 27

What are the functions of the kidneys?

Answer 27

1. Regulation of water, inorganic ion compositions, acid-base balance, and water volume. (They do so by excreting enough water to maintain the proper concentrations). 2. Removal of the metabolic waste products from the blood by urinary excretion. 3. Removal of foreign chemicals. 4. Gluconeogenesis: During prolonged fasting, the kidneys can synthesis glucose and release it into the blood. 5. Production of hormones/enzymes: A) Erythropoietin: Controls erythrocyte production B) Renin: Enzyme that controls the formation of angiotensin, which influences blood pressure and sodium balance. C) 25-hydroxyvitamin D to 1, 25 hydroxyvitamin D, which influences calcium balance.