Section 2

Question 1

What inputs are the kidneys controlled by?

Answer 1

Endocrine and neural

Question 2

What are the primary function of the kidneys?

Answer 2

Maintain the ECF volume, electrolyte composition and osmolarity

Question 3

Describe how kidneys act in presence of excess/too little water.

Answer 3

In excess water or excess particular electrolyte (solute), the kidneys will increase their elimination

In times of deficit of water or a solute, the kidneys CANNOT actively correct this. However, they can further reduce their elimination.

Question 4

List all the major functions of the kidneys (10)

Answer 4

1. Maintain water balance in the body
2. Maintain body fluid osmolarity
3. Maintain proper plasma volume
4. Help maintain acid-base balance
5. Regulate ECF solutes (such as sodium, potassium, chloride, calcium, phosphate, and others)
6. Excrete wastes of metabolism
7. Excrete foreign compounds ingested
8. Produce erythropoietin
9. Produce renin
10. Activate vitamin D

Question 5

Where are the kidneys located?

Answer 5

associated with the adrenal gland (one on top of each kidney)

Question 6

What is the structure of the kidney? (outer to inner part, and basic unit)

Answer 6

The outside is the renal cortex, and the inner part is the renal medulla.

At the inner core of each kidney is the renal pelvis, through which the urine empties and is channeled to the ureter

the nephron is the basic functional unit of the kidney

Question 7

What compartments is the nephron divided into?

Answer 7

The vascular component, which supplies blood to the nephron

The tubular component, which carries the filtrate throughout the nephron

Question 8

What is the major part of the vascular component of the nephron?

Answer 8

The major part is the glomerulus, which is a ball-like capillary through which water and solutes are filtered from the plasma.

Question 9

How does blood enter the kidney?

Answer 9

Blood enters the kidney via the renal artery, which subdivides into many small afferent arterioles, each supplying a nephron.

Question 10

What transports unfiltered blood from the glomerulus?

Answer 10

The efferent arterioles transport unfiltered blood from the glomerulus.

Question 11

How are the capillaries of the nephron different from typical capillaries?

Answer 11

In the capillaries of the nephron, arterial blood enters and then leaves without extracting oxygen. Instead, the efferent arterioles subdivide into peritubular capillaries, which deliver oxygen to the renal tissues.

Question 12

Describe the flow of blood through the vascular component of the nephron.

Answer 12

Blood enters the kidney via the renal artery, which subdivides into afferent arterioles supplying each nephron. Within the glomerulus, blood is filtered, and unfiltered blood exits via efferent arterioles. The efferent arterioles then divide into peritubular capillaries, delivering oxygen to renal tissues before merging into venules and eventually the renal vein for blood exit.

Question 13

What is the structure that collects fluid filtered from the glomerular capillaries?

Answer 13

Bowman’s capsule encircles the glomerulus to collect the filtered fluid.

Question 14

Where is the proximal tubule located and what is its structure?

Answer 14

The proximal tubule, located within the renal cortex, is highly coiled along its length.

Question 15

Describe the structure and location of the loop of Henle.

Answer 15

The loop of Henle forms a hairpin loop that dips down into the renal medulla. The descending limb travels from the cortex to the medulla, while the ascending limb travels from the medulla back to the cortex.

Question 16

What region does the ascending limb of the loop of Henle pass through?

Answer 16

The ascending limb passes through the fork of the afferent and efferent arteries in a region called the juxtaglomerular apparatus.

Question 17

What is the structure that follows the distal tubule, and where does it ultimately drain?

Answer 17

The distal tubule empties into a collecting duct, which travels deep into the medulla and drains into the renal pelvis.

Question 18

Describe the flow of fluid through the tubular component of the nephron.

Answer 18

Filtered fluid enters Bowman’s capsule, then moves into the highly coiled proximal tubule in the renal cortex. It continues through the loop of Henle, which dips into the renal medulla, and returns to the cortex via the ascending limb. Passing through the juxtaglomerular apparatus, it enters the coiled distal tubule before emptying into a collecting duct, which extends deep into the medulla and drains into the renal pelvis.

Question 19

What are the two types of nephrons?

Answer 19

Cortical nephrons and juxtamedullary nephrons

Question 20

What are cortical nephrons?

Answer 20

Cortical nephrons primarily serve secretory and regulatory functions.

The glomeruli of cortical nephrons lie in the outer layer of the cortex.

Question 21

How deep does the loop of Henle of cortical nephrons dip into the renal medulla?

Answer 21

The loop of Henle of cortical nephrons only slightly dips into the renal medulla.

Peritubular capillaries from cortical nephrons wrap around the short loops of Henle.

Question 22

What are juxtamedullary nephrons responsible for and where are they found?

Answer 22

Juxtamedullary nephrons are responsible for the concentration and dilution of urine.

Juxtamedullary nephrons are found on the inner layer of the cortex.

Question 23

What structures form hairpin loops of vasculature near the long loops of Henle in juxtamedullary nephrons?

Answer 23

Peritubular capillaries from juxtamedullary nephrons form hairpin loops of vasculature, called the vasa recta, which are in close proximity to the long loops of Henle.

Question 24

Arrange these terms in the order of which blood flows from the renal artery to the renal vein in the nephron:

• Peritubular capillaries
• Afferent arteriole
• Glomerulus
• Efferent arteriole

Answer 24

1. Afferent arteriole
2. Glomerulus
3. Efferent arteriole
4. Peritubular capillaries

Question 25

Arrange these terms in order of by which solutes flow from Bowman’s capsule to the renal pelvis within the nephron:

• Collecting duct
• Proximal tubule
• Loop of Henle
• Distal tubule

Answer 25

1. Proximal tubule
2. Loop of Henle
3. Distal tubule
4. Collecting duct

Question 26

What is glomerular filtration? What % of blood is filtered?

Answer 26

Glomerular filtration is the process where about 20% of the blood flowing through the glomerular capillaries is filtered into Bowman’s capsule. This filtrate is protein-free but contains the same solutes as plasma, forming about 125 ml of glomerular filtrate per minute.

Question 27

What is tubular reabsorption?

Answer 27

Tubular reabsorption is the process where important substances in the filtrate are returned to the peritubular capillaries as the filtrate flows through the tubules. Approximately 178.5 liters of the 180 liters of plasma filtered each day are reabsorbed through this process.

Question 28

What is tubular secretion?

Answer 28

Tubular secretion is the selective transfer of substances from the peritubular capillaries into the renal tubules. This process allows for the excretion of selected substances from the remaining 80% of the plasma, as only 20% of the plasma is filtered in the glomeruli.

Question 29

T or F: The cortical nephron lies in the outer layer of the cortex.

Answer 29

True

Question 30

T or F: The cortical nephron is mainly responsible for urine concentration/dilution

Answer 30

False! The juxtamedullary nephron is

Question 31

T or F: In the juxtamedullary nephron, vasa recta are in close proximity to the long loops of Henle

Answer 31

True

Question 32

T or F: The juxtamedullary nephrons primarily serve secretory and regulatory functions

Answer 32

False! The cortical nephrons do

Question 33

T or F: the cortical nephrons are about 80% of all nephrons

Answer 33

True

Question 34

T or F: The cortical nephrons lie within inner layer of cortex

Answer 34

False! The juxtamedullary nephrons do

Question 35

T or F: In the cortical nephron, peritubular capillaries form hairpin loops of vasculature, called the vasa recta

Answer 35

False! This is in the juxtamedullary nephron

Question 36

T or F: In the cortical nephron the Loop of Henle only slightly dips into renal medulla

Answer 36

True