Question

Which of the following sequences correctly shows the passage of blood flow through the vessels of the kidney? A. Renal artery \(\rightarrow\) afferent arterioles \(\rightarrow\) glomerulus \(\rightarrow\) efferent arterioles \(\rightarrow\) vasa recta \(\rightarrow\) renal vein B. Afferent arterioles \(\rightarrow\) renal artery \(\rightarrow\) glomerulus \(\rightarrow\) vasa recta \(\rightarrow\) renal vein \(\rightarrow\) efferent arterioles C.Glomerulus \(\rightarrow\) renal artery \(\rightarrow\) afferent arterioles \(\rightarrow\) efferent arterioles \(\rightarrow\) renal vein \(\rightarrow\) vasa recta D. Renal vein \(\rightarrow\) efferent arterioles \(\rightarrow\) glomerulus \(\rightarrow\) afferent arterioles \(\rightarrow\) vasa recta \(\rightarrow\) renal artery

Short answer

A. Renal artery \rightarrow afferent arterioles \rightarrow glomerulus \rightarrow efferent arterioles \rightarrow vasa recta \rightarrow renal vein

Step-by-step solution

- Identify the Starting Point

The blood flow through the kidney begins with the renal artery. This is the vessel that supplies blood to the kidney from the heart.

- Identify the Next Vessels

Next, the blood flows from the renal artery into the afferent arterioles, which are small branches that carry blood into the nephron.

- Flow Through the Glomerulus

From the afferent arterioles, blood enters the glomerulus, a bundle of capillaries where filtration occurs.

- Efferent Arterioles

After passing through the glomerulus, the blood moves into the efferent arterioles.

- Vasa Recta

The efferent arterioles then lead to the vasa recta, a series of capillaries that are involved in the concentration of urine.

- Renal Vein

Finally, the blood exits the kidney through the renal vein, which carries it back toward the heart.

Key concepts

renal artery

The renal artery plays a vital role in kidney blood flow. It is the main blood vessel that brings oxygenated blood from the heart to the kidney.
The renal artery branches off directly from the aorta, the largest artery in the body.
This strong and thick-walled artery ensures that the kidney receives a high-volume blood supply, which is crucial for its functions in filtering and balancing bodily fluids.

afferent arterioles

Once the blood enters the kidney through the renal artery, it flows into smaller vessels called afferent arterioles.
These arterioles are like tiny branches that bring blood into the nephron, the functional unit of the kidney.
The afferent arterioles play a critical role in regulating blood pressure within the kidney, ensuring that an adequate amount of blood reaches the glomeruli for filtration.

glomerulus

The blood then flows into the glomerulus, a key part of the nephron.
The glomerulus is a bundle of tiny blood vessels (capillaries) where blood filtration occurs.
Here, water and solutes are filtered out of the blood, while larger cells and proteins remain. This filtration process is the first step in urine formation.

efferent arterioles

After filtration in the glomerulus, the remaining blood flows into the efferent arterioles.
These vessels are smaller than the afferent arterioles and carry filtered blood away from the glomerulus.
The efferent arterioles help maintain the pressure needed for continued blood filtration and are crucial for directing blood to the next stage.

vasa recta

The efferent arterioles eventually lead to the vasa recta, a network of capillaries that play a role in urine concentration.
The vasa recta surrounds the loop of Henle in the nephron, helping in the reabsorption of water and solutes.
This process helps to concentrate urine and maintain the body’s fluid balance by managing the water and salt content in the urine.

renal vein

Finally, the filtered and processed blood exits the kidney through the renal vein.
The renal vein collects deoxygenated blood and returns it to the heart via the inferior vena cava.
This completes the cycle of blood flow in the kidney, ensuring that waste products are removed and necessary substances are reabsorbed.