#3: Excretory System and Urine Production

Question 1

Waste Products

Answer 1

Lungs – eliminate CO2
Large intestine – eliminates toxic wastes and indigestible products
Liver – transforms chemicals and toxins like alcohol, heavy metals, lactic acid and protein metabolism products

Question 2

Protein Wastes

Answer 2

Proteins produce nitrogenous waste products that must be discarded from the body
Nitrogen and Hydrogen atoms are removed from proteins by a process called deamination (removal of amino group from amino acid/nucleic acids)

Question 3

Deamination

Answer 3

Occurs in the liver
Produces ammonia, which is very toxic
Ammonia converted in the liver to urea (1 million times less toxic and more soluble in water) – save water

Question 4

Kidney Function

Answer 4

• Filters waste from the blood (urea, uric acid) through formation of urine
• Balancing blood pH
• Maintain water balance

Question 5

Cortex

Kidney Structure

Answer 5

outer layer of connective tissue

Question 6

Medulla

Kidney Structure

Answer 6

inner layer, contains renal pyramids

Question 7

Renal Pelvis

Kidney Structure

Answer 7

where urine exits the kidney and enters the ureter

Question 8

Nephrons

Kidney Structure

Answer 8

within the cortex and medulla

responsible for the formation of urine

Question 9

1. Filteration

Formation of Urine

Answer 9

Movement of substances from the blood into the nephron at the glomerulus

Fluid in capsule (filtrate) contains water, glucose, ions, amino acids, and urea

Large materials like proteins and blood cells are unable to pass through

blood enters the glomerulus via an afferent arteriole

some dissolved substances will diffuse through the walls of the glomerulus into the Bowman’s capsule

the dissolved substances move from the Bowman’s capsule into the proximal tubule

filtered blood leaves the glomerulus via an efferent arteriole

the efferent arteriole wraps around the nephron tubule in a network of capillaries called the peritubular capillaries

Question 10

2. Reabsorption

Formation of Urine

Answer 10

refers to the movement of substances from the tubule back into the blood via the peritubular capillaries

water is reabsorbed at the proximal tubule, the descending loop of Henle, and the distal tubule via osmosis (can also be reabsorbed at the 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 11

3. Secretion

Formation of Urine

Answer 11

refers to the movement of substances from the blood into the nephron via the peritubular capillaries

H+, K+, toxins, ammonia moves into the nephron at the proximal and distal tubules via active transport

Question 12

Excretion

Answer 12

after urine has been produced and concentrated in the nephron, it leaves the nephron via collecting ducts

the collecting ducts merge in the renal pelvis and the urine will enter the ureter

the ureter carries urine to the bladder

the urethra carries the urine from the bladder to the outside environment