Section 2

Question 1

What do the kidneys function to do (general)?

Answer 1

• filter blood to produce urine

Question 2

Where are the kidneys located?

Answer 2

On either side of the spine at the level of the T12-L2 vertebrae.

Question 3

How big are kidneys?

Answer 3

They are roughly ‘fist-sized’ organs that lay against the posterior abdominal wall.

Average size:
- 12 cm in length
- 6.5 cm in width
- 2.5 cm in thickness

Question 4

Why does the right kidney sit slightly lower in the abdominal cavity than the left one?

Answer 4

• because of the liver which sits superiorly
• it limits the ascent of the kidney during embryologic development

Question 5

What is the hilum of the kidney?

Answer 5

A concave surface where:
- the renal arteries and nerves enter
- renal veins and ureters exit
It is continuous with an internal space in each kidney called the renal sinus which is filled with fatty tissue

Question 6

What is the renal sinus filled with?

Answer 6

Fatty tissue

Question 7

What is the renal capsule?

Answer 7

• aka fibrous capsule
• covers outer surface of the kidney
• composed of dense irregular connective tissue, which functions to protect the kidney from injury and pathogens, as well as maintain the shape of the kidneys

Question 8

What kind of connective tissue is the renal capsule composed of?

Answer 8

Dense irregular connective tissue

Question 9

What is the adipose capsule?

Answer 9

• perinephric fat
• a layer of adipose tissue external to the renal capsule
• cushions and protects by completing surrounding the kidney

Question 10

What are the two supportive tissues of the kidney?

Answer 10

Renal capsule and adipose capsule

Question 11

What are the regions of the kidney, and what do they do (general)?

Answer 11

Cortex - outer layer
Medulla - deep to the cortex

They filter blood to make urine

Question 12

How are renal lobes formed?

Answer 12

Extensions of the cortex, called renal columns, separate the medulla into renal pyramids.

The renal pyramid, its overlying cortex, and surrounding renal column make up a renal lobe.

Question 13

What is the apex of a renal pyramid called?

Answer 13

Renal papilla

Question 14

Where does urine travel to and from?

Answer 14

Urine produced in the kidneys flows through the renal papilla into a funnel shaped space termed minor calyx.

Each minor calyx drains into a major calyx, and then into the large renal pelvis, which continues on as the ureter.

Question 15

Where do the kidneys receive their blood from?

Answer 15

Paired renal arteries - branches of the abdominal aorta

Question 16

Where do the kidneys drain their blood to?

Answer 16

The kidneys are drained by the renal veins, which are anterior to the arteries and drain into the inferior vena cava (IVC)

Question 17

Describe the differences in length of the left/right renal arteries/veins.

Answer 17

• The right renal ARTERY is longer
• The right renal VEIN is SHORTER
• Due to the positioning of the IVC and descending aorta
• The descending aorta is to the left of the IVC, making the left renal artery shorter compared to the right renal artery
• the left renal vein is longer because the IVc is to the right of the descending aorta.
• the renal veins are also anterior to the renal arteries

Question 18

What are nephrons?

Answer 18

• in the kidney
• filters blood and produces urine
• composed of two parts, a renal corpuscle and a renal tubule

Question 19

What is the renal corpuscle/what is the composition?

Answer 19

• composed of two structures: a glomerulus and a glomerular capsule (aka Bowman’s capsule)
• the glomerulus consists of a bundle of capillaries enclosed within the glomerular capsule. this capsule creates a space between its walls and the glomerular capillaries, called the capsular (Bowman’s) space

Question 20

Describe the flow of blood/materials in the renal corpuscle.

Answer 20

Blood flows into the kidney and to the glomerular capillaries. Filtration occurs when components of the blood move out from the capillary into the Bowman’s space. The material in the Bowman’s space is known as filtrate.

The capillaries of the glomerulus have small holes (fenestrations) that allow ions, water, and other molecules to move through their membranes. The glomerular capillaries are also surrounded and supported by specialized cells called podocytes. These cells wrap their foot-like processes around the glomerular capillaries creating filtration slits that permit the passage of water and salts and restrict the passage of proteins.

Question 21

What is the renal tubule/the sections of it.

Answer 21

It extends throughout the cortex and medulla of the kidney.

Divided into three sections: the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule.

Each section has a specific function in the reabsorption or secretion of substances such as ions, proteins and water to and from the filtrate.

Question 22

Describe the collecting system (the path of the filtrate through it).

Answer 22

From the renal tubules, the filtrate travels into the collecting tubules, and then to the collecting ducts that travel within the renal medulla.

The final processing of the filtrate occurs in the collecting duct where it is further modified. Once the filtrate leaves the collecting duct at the renal papilla, it can be called urine.

Question 23

What is the juxtaglomerular apparatus?

Answer 23

A specialized structural unit that regulates the blood pressure of the body by monitoring ion concentrations in the filtrate.

Question 24

What are juxtaglomerular cells?

Answer 24

Modified smooth muscle cells of the afferent arteriole which is a small artery that brings blood into the glomerulus.

Question 25

What are macula densa?

Answer 25

Modified cuboidal cells of the distal convoluted tubule.

Question 26

Describe the function of the kidney, and how it does this.

Answer 26

• filters blood to rid the body of wastes, balance ion concentrations and body fluid volume, and produce erythropoietin (a hormone that stimulates the production of red blood cells)
• produces urine via the nephrons, and passes the filtrate on to the minor and major calyces, and into the renal pelvis where it drains into the ureters