Structure and Function of the Kidney and Nephron

Question 1

what is the function of the kidney

Answer 1

regulates extracellular fluid environment by filtering blood and producing urine

Question 2

the kidneys are involved in the homeostasis of what?

Answer 2

• blood volume
• metabolic waste products
• water and electrolyte balance
• acid/base balance (pH)

Question 3

what are the major blood vessels associated with the kidneys

Answer 3

renal artery and renal vein

Question 4

function of the urethra

Answer 4

drains the bladder

Question 5

why do sea otters and other marine mammals have reticulate kidneys

Answer 5

lots of surface area

Question 6

what is the functional unit of the kidney

Answer 6

the nephron is the functional unit of the kidney

Question 7

describe the three main (basic) steps to functionality of the kidney

Answer 7

1. blood goes in at glomerulus
2. blood is filtered through nephron
3. urine goes out collecting duct

Question 8

where are the nephrons located?

Answer 8

80% of nephrons are cortical

20% are juxtamedullary

Question 9

how many nephrons are in each kidney

Answer 9

10^6

Question 10

what are the four regions of each nephron

Answer 10

1. Bowmans capsule: contains the glomerulus (renal corpuscle)
2. proximal convoluted tubule
3. loop of Henley (the only region that dips into medulla)
4. distal convoluted tubule (DCT)

Question 11

describe the small blood vessels that are associated with the nephron

Answer 11

Afferent and Efferent arterioles:
- interlobular artery extensors to afferent arteriole
- efferent arteriole eventually emptied into interlobular capillaries (vasa recta)
Peritubular

Question 12

what does ADH act on?

Answer 12

collecting ducts (which are not typically considered to be part of the nephron)

Question 13

describe the three steps in which urine is formed within the nephron

Answer 13

1. Filtration: movement of fluid from blood to lumen of nephron (only takes place in renal corpuscle)
2. reabsorption: after filtrate leaves bowman’s capsule, it is modified by reabsorption- solutes in the nephron tubule’s filtrate are moved back to the blood
3. secretion: blood moves select solute back to the nephron tubule’s filtrate

Question 14

how much fluid per day enters the nephron compared to how much urine is released

Answer 14

180L of fluid/day enters nephron

1.5L/day of urine