Urinary System

Question 1

Lungs

Answer 1

carbon dioxide and water vapor diffuse from the blood and are continually exhaled

Question 2

Skin

Answer 2

the sweat glands excrete water and dissolve salts

Question 3

Liver

Answer 3

processes nitrogenous wastes, hemoglobin, and other chemicals for excretion

Question 4

Kidneys

Answer 4

• maintain the osmolarity of the blood, excrete numerous waste products and toxic chemicals and conserve glucose, salt and water
• regulate the concentration of salt and water in the blood through the formation and excretion of urine
• located behind the stomach and liver
• composed of ~ 1 million units called nephrons

Question 5

Structure of the Kidneys

Answer 5

-divided into 3 regions: outer cortex, inner medulla, and the renal pelvis

Question 6

Nephron

Answer 6

consists of the Bowman’s capsule, which embraces a special capillary bed called a glomerulus

Question 7

Bowman’s capsule

Answer 7

leads to a long, coiled tubule divided into: proximal convuluted tubule, the loop of Henle, the distal convuluted tube, and the collected duct

Question 8

Medulla

Answer 8

this is where the loop of Henle and collected duct run through

Question 9

Cortex

Answer 9

this is where the convuluted tubules and Bowman’s capsules are

Question 10

Ureters

Answer 10

empty into the urinary bladder, where urine collects until expelled via the urethra

Question 11

Urine Formation

Answer 11

1. Filtration: blood pressure forces 20% of blood plasma in the glomerulus through its capillary walls and into the Bowman’s capsule. The fluid and small solutes entering the nephron are called the filtrate (isotonic w/ blood plasma). Particles too large to filter in the glomerulus remain in the circulatory system. High blood pressure can lead to kidney damage over time
2. Secretion: the nephron secretes waste substances from the interstitial fluid into the filtrate by both passive and active transport
3. Reabsorption: essentail substances and water are reabsorbed from the filtrate and returned to the blood. Occurs primarily in the proximal convuluted tubule and is an active process (concentrated urine)

Question 12

Nephron Function

Answer 12

• regulates the balance of salt and water through selective permeability and osmolarity gradient
• primary function is to clean the blood plasma of unwanted substances as the filtrate passes through the kidney
• nephron will selectively reabsorb wanted substances back into the plasma
• nutrient reabsorption occurs in the proximal convuluted tube
• the distal convuluted tubule is a major site for secretion of substances into filtrate
• by existing and then re-entering at different segments of the nephron solutes such as Na+ Cl- create the osmaliraty gradient with increasing from the cortex to the inner medulla
• regulation of the permeability of the collecting ducts to water is accomplished by antiduiretic hormone (ADH) allows for more water to be absorbed