The Urinary System

Question 1

Where are the kidneys located?

Answer 1

• Lie on either side of the vertebral column
• high on the posterior wall of the abdominal cavity
• receive some protection from the lower ribcage
• between the 12th thoracic and 13th lumbar vertebrae

Question 2

The kidneys are positioned retroperitoneally, what does this mean?

Answer 2

• This means that they are behind the parietal peritoneum and against the deep muscles of the back.

Question 3

describe the kidney’s structure?

Answer 3

• Reddish-brown, bean-shaped organ with a smooth surface
• Each kidney is enclosed and protected by a tough, fibrous capsule covered by a mass of fat, and an outermost fascia composed of dense fibrous connective tissue. This tissue helps hold the kidney in position.

Question 4

What is the renal medulla?

Answer 4

The inner part of the kidney

Question 5

what is the renal medulla composed of?

Answer 5

It is composed of conical masses of tissue called renal pyramids, that look striated in appearance.

Question 6

what is the renal cortex?

Answer 6

the outer part of the kidney

Question 7

What does the renal cortex do?

Answer 7

It appears granular, forming a shell around the renal medulla and dips into the medulla between the renal pyramids, forming renal columns.

Question 8

What is a nephron?

Answer 8

The functional unit of the kidney. It produces urine in the process of removing waste and excess substances from the blood.

Question 9

How many nephrons are there in each human kidney?

Answer 9

1,000,000

Question 10

What is the renal pelvis?

Answer 10

A funnel-shaped cavity in a kidney that channels urine to the ureter.

Question 11

Beginning at the renal papilla, what is the direction of urine flow out of the body?

Answer 11

Renal Papilla (tip of pyramid)
minor calyx
major calyx
renal pelvis 
ureter
urinary bladder
urethra

Question 12

What are the functions of the kidney?

Answer 12

• Controls the volume and composition of the extracellular fluid in order to maintain homeostasis
• Remove wastes from the blood, mix them with extra water and various electrolytes, and excrete them as urine
• Activate Vitamin D to help with calcium absorption
• Secrete the hormone erythropoietin, which increases red blood cell synthesis, and the enzyme renin, which helps regulate blood volume and blood pressure.

Question 13

What is the function of the renal arteries, in relation to the kidneys?

Answer 13

They arise from the abdominal aorta and supply blood to the kidneys.
They transport a large volume of blood,

Question 14

What do the renal arteries do when a person is at rest?

Answer 14

They usually carry about one-fourth of the total cardiac output into the kidneys.

Question 15

Discuss the steps taken in relation to renal blood supply?

Answer 15

1. A renal artery enters the kidney through the hilum and divides into segmental arteries that branch into several interlobar arteries, which pass between the renal pyramids.
2. At the junction between the medulla and cortex, the interlobar arteries branch, forming a series of incomplete arches, arcuate arteries, which in turn gives rise to cortical radiate arteries that project up into the cortex.
3. The final branches of the cortical radiate arteries (afferent arterioles) lead to the nephrons.
4. Each afferent arteriole delivers blood to a mass of fenestrated blood capillaries, called the glomerulus.