urinary system/kidneys

personal notes

what is the function of the urinary system?

to maintain the body’s acid/base balance

what is the basic function of the kidneys?

to cleanse blood

what structures are involved in the urinary system?

• kidneys

• ureters

• bladder

• urethra

• urethra meatus

what are the two sections of the kidneys?

• the cortex

• the medulla

what does the cortex of the kidneys contain?

the majority of nephrons

how many nephrons are there per kidney?

1-2 million

what does the medulla of the kidneys contain?

most of the collecting tubules

what do the collecting tubules do?

they carry urine from nephrons through the kidney to the ureters

what are the ureters?

two muscular tubes around 10-12 inches long that extend from the renal pelvis of each kidney to the bladder

what is the bladder?

a hollow sac that is lined by rugae (folds) which allows it to expand as urine is collected

what is the volume that the bladder can contain?

typically 1 cup

what is the urethra tube?

it carries urine from the bladder to outside of the body

the urethra tube in females;

• 1.5 inches long

• separate from the reproductive system

the urethra tube in males;

• 8 inches long

• is shared with the reproductive system

what is urine?

the waste product that the urinary system produces

what is the majority of urine comprised of?

95% water

how much blood is filtered by the kidneys in a day?

150 quarts

how much urine is produced in a day?

1.5-2 quarts (around 1 litre)

what is the nephron?

the functional unit of the kidney where blood filtration occurs

what are the parts of the nephron?

• the renal corpuscle

• the proximal convoluted tubule

• the loop of Henle

• the distal convoluted tubule

• collecting duct

what is the renal corpuscle made of?

the glomerulus and Bowman’s capsule

where does the majority of blood filtration in the nephron occur?

the glomerulus

what type of nephron is the loop of Henle?

a juxtamedullary nephron

what happens to the concentration of urine in the descending loop of Henle?

it increases

what is the descending loop of Henle permeable to?

water

what happens to the concentration of urine in the ascending loop of Henle?

it decreases

what is the ascending loop of Henle permeable to?

sodium ions