Formation of urine

Question 1

What are the three ways the kidney functions and what is its main goal?

Answer 1

• Kidneys help maintain homeostasis by filtering blood
  THREE FUNCTIONS…
• remove waste from blood
• Maintain electrolyte, pH, and water balance in blood
• Release key hormones

Question 2

Kidney structure

Answer 2

• pair of bean shaped organs
• two layers: renal medulla and cortex
• blood flow in and out through renal artery and vein
• filtering units called nephrons

Question 3

What is the main function of nephron?

Answer 3

clean blood and produce urine

Question 4

3 steps nephrons go through

Answer 4

3 step blood cleaning process
1. filtration of blood
2. reabsorption of materials
3. excretion of waste

Question 5

What does the glomerulus do?

Answer 5

FILTRATION
- Blood solution is forced into high pressure capillary network of glomerulus
- Due to thin walls of vessels blood plasma and solutes exit cell -> water, salts, glucose, and small proteins
- arteriole is left with just rbc, wbc, platelets, etc

Question 6

What does Bowmans capsule do?

Answer 6

FILTRATION
- collecting chamber of nephron
- first outside of body structure

Question 7

How much blood goes through step one, FILTRATION

Answer 7

120mL/min

Question 8

What does the proximal tubule do?

Answer 8

REABSORPTION
- 90% of filtrate back in
- Active: glucose, Na+, K+, Mg2+, Ca2+
- Passive: Cl- , H20 (osmosis)

Question 9

What is vasa recta and what does it do?

Answer 9

• capillary network surrounding nephron
• reabsorbs things out of urine into blood

Question 10

What is the role of the loop of henle?

Answer 10

• Na+ and H2O reabsorption

Question 11

Descending loop of henle

Answer 11

REABSORPTION
- lined with a lot of aquaporins
- H2O osmosis out since outside is very salty due to ascending loop
- leaves us with very salty pee at the bottom

Question 12

Ascending loop of henle

Answer 12

REABSORPTION
- no aquaporins
- Na+ actively transported out while Cl- follows passively
- Creates hypertonic env

Question 13

Distal tubule

Answer 13

REABSORPTION and SECRETION
- Reabsorption of salts actively
- Reabsorption of H2O by osmosis
- Secretion of NH3 by diffusion
- secretion of H+, K+ drugs, and toxins actively

Question 14

What is SECRETION

Answer 14

movement of wastes from blood into nephron not through glomerulus

Question 15

Collecting Duct

Answer 15

• REABSORPTION
• H2O exits by osmosis regulated by ADH
• SOMETIMES when needed, urea is reabsorbed too
• all collecting ducts join together and collect USUALLY STERILE URINE at this point

Question 16

How much stuff is reabsorbed into blood?

Answer 16

119ml/min

Question 17

How much urine is made?

Answer 17

1ml/min

Question 18

EXCRETION

Answer 18

anything not reabsorbed or secreted into nephron is collected into renal pelvis then into ureter into bladder, and out urethra as pee