Exretory System And Urine Production

Question 1

Protein waste

Answer 1

• occurs in liver
• produces Ammonia (toxic)
• ammonia -> urea (less toxic, more water soluble)

Question 2

Deamination

Answer 2

Removal of amino group from amino acid

Question 3

Function of kidneys

Answer 3

• filters waste from blood (urea, uric acid) through formation of urine
• balances blood pH and electrolytes
• maintain water balance

Question 4

Structure of kidneys

Answer 4

• cortex: outer layer of connective tissue
• medulla: inner layer, contains renal pyramids
• renal pelvis-where urine exits the kidney and enters the ureter

Nephrons responsible for urine formation within cortex and medulla

Question 5

3 stages of urine formation

Answer 5

1) filtration
2) reabsorption
3) secretion

Question 6

Describe filtration

Answer 6

• blood plasma (glucose, H2O, amino acids, ions) are filtered from glomerulus into Bowman’s capsule
• RBC, WBC, large proteins can’t pass
• movement of substances from blood into nephron at glomerulus
• filtrate in capsule
• large materials like protein and blood cells can’t pass
• blood enters glomerulus through afferent arteriole
• dissolved substances dissolve through walls of glomerulus into Bowman’s capsule
• dissolved substances move from Bowman’s capsule into the proximal tubule, filtered blood leaves glomerulus via an efferent arteriole
• efferent arteriole wraps around nephron tubule in network of capillaries called peritubular capillaries

Question 7

Filtrate consists of (5 things)

Answer 7

Water, glucose, ions, amino acids, urea

Question 8

Describe reabsorption

Answer 8

• refers to the movement of substances from tubule back into the blood via the peritubular capillaries
• body will reabsorb everything it can reuse (glucose, ions, H2O)
• happens throughout nephron
• water is reabsorbed at the proximal tubule, descending loop of Henle, and distal tubule via osmosis
• water can also be reabsorbed at collecting duct when needed
• glucose, amino acids, ions, vitamins, and minerals are reabsorbed at the proximal tubule via active transport
• some urea diffuses out into blood as well, only to be processed by the kidney again

Question 9

Describe secretion

Answer 9

• refers to movement of substances from blood into nephron via peritubular capillaries
• ions, toxins, ammonia moves into nephron at the proximal and distal tubules via active transport

Question 10

Glomerulus and Bowman’s capsule function

Answer 10

• cortex
• Ions (Na+, Cl-, and H+), small nutrients (glucose), nitrogenous wastes (amino acids, urea, and uric acid), vitamins and minerals are filtered into Bowman’s capsule
• water and small substances, but no proteins, pass into the nephrons

Question 11

Proximal convoluted tubule function

Answer 11

• cortex
• ions are actively reabsorbed, water leaves through the aquaporins, and H+ ions are actively secreted. Glucose, amino acids, and other nutrients are actively reabsorbed
• some ions, water, and urea, and ALL nutrients are reabsorbed. pH balance is maintained.

Question 12

Descending loop of Henle function

Answer 12

• cortex into medulla
• water leaves through aquaporins
• additional water is returned to interstitial fluid

Question 13

Ascending loop of Henle function

Answer 13

• Medulla into cortex
• Na+ and Cl- are actively transported out, there is no entry of water and no movement of urea
• additional ions are returned to the interstitial fluid

Question 14

Distal convoluted tubule function

Answer 14

• cortex
• K+ and Na+ are secreted via active transport into the urine. Na+ and Cl- are reabsorbed. Water moves into theurine through the aquaporins.
• ionic and pH balance are maintained

Question 15

Collecting ducts function

Answer 15

• cortex through medulla, into renal pelvis
• water moves out via the aquaporins. There is no movement of ions. Some urea leaves at the bottom of the collecting ducts
• more water and some urea are returnedto the interstitial fluid. Some H+ ions are added to urine