The formation of urine begins with the glomerulus secreting filtrate into Bowman

Question

The formation of urine begins with the glomerulus secreting filtrate into Bowman's capsule, but as the filtrate moves through the tubules, more particles might be secreted into or absorbed from the fluid. These particles must move between the tubules and the capillaries. The following image shows the basic structure of the nephron tubules, the peritubular capillaries, and the interstitial fluid that separates them.

Question #1

In tubular secretion, particles move from the plasma in __ _, through the fluid of-----, into the gap between cells in ------, through gates or channels in ------, through the cellular space in -------, through other gates or channels in -----, and finally from there into the filtrate of ------.

Question #2

If the particles move through this entire process by diffusing down gradients, either osmotic or electrochemical, that would be an example of ______passive or active_______.  

Different particles are absorbed and secreted at different parts of the nephron, depending on the homeostatic needs of the body. The following table summarized the main reabsorptions that occur in the nephron. For each, select whether it occurs in the proximal tubules, distal tubules and collecting ducts, or both.

The following table summarizes the main tubular secretions that occur in the nephron. For each, select whether it occurs in the proximal tubules, distal tubules, or both.

Sodium ion reabsorption is the most important particle reabsorption that occurs in the kidneys. It occurs in both the proximal and distal tubules, but most Na^+ in the filtrate is ___actively or passively ____ reabsorbed in the ___(2)___. Variable levels of Na^+ reabsorption, controlled by ____(3)____, occur in the _____prpximal or distal_____. For all Na^+ movement, ___(5)_____ automatically follows in the same direction.

(2) proximal or distal

(3) angiotensin, vasopressin, or aldosterone

(5) water, chloride, or potassium

Reabsorption Description Proximal Tubule Distal Tubule and Ducts All filtered glucose and amino acids actively reabsorbed 50% of filtered urea passively reabsorbed Variable amounts of filtered PO_4^3- and other electrolytes reabsorbed Variable H_2O reabsorption, controlled by vasopressin 65% of filtered water reabsorbed by osmosis, not controlled Almost all filtered K^+ reabsorbed nd the interstitial fluid that separates them. Interstitial fluid Peritubular capillary Lumen Tubular cell

Explanation / Answer

Question 1

In tubular secretion the particle move from the plasma in E through the fluid of F into the gap between cells G, through gates or channels in A, through the cellular space in B, through other gates or channels in C, and finally from there into the filtrate of D.

Question 2-

Passive osmosis. Passive osmosis is the process of movement of particles down the gradient and active is the movement against the gradient. Answer is passive.

Question 3-

Variable K+ secretion controlled by aldosterone

Yes

(1) actively. It occurs via Na+ pumps spending energy.

(2) proximal.

(3) Aldosterone. Angiotension has no direct action and vassopresin works for water. Thus answer Aldosterone.

(4) distal - Aldosterone acts here for ion reabsorption.

(5) water - it occurs due to change in osmotic concentration.

Reabsorption description Proximal tubule Distal tubule and duct All filtered glucose and amino acids are actively absorbed. Yes No 50% of filtered urea passively absorbed. Yes No Variable amount of filtered phosphate and other electrolytes reabsorbed. Yes No Variable H20 Reabsorption controlled by vassopresin No Yes 65% of filtered water reabsorbed by osmosis, not controlled Yes No Almost all filtered potassium Reabsorbed No yes

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.