Nephron, Kidney, Raas

Kieser, Jan 29

What is Filtration?

High pressure movement of water and small solutes from the blood into the Bowman’s capsule.

What is Reabsorption? Where does it take place?

 Moving needed substances (glucose, water, ions) from the filtrate back into the blood. The PCT, DCT, loop of henle, and collecting duct.

What is Secretion?

Active movement of waste ions (H+, K+) and drugs from the blood into the renal tubule for excretion.

Where does filtration occur? How does the blood get there?

Occurs in the Glomerulus. High blood pressure forces it into the Bowman’s capsule.

Where is the primary sight for reabsorption? What two things does it reclaim.

The PCT, reclaims nearly 100% of the bodies glucose and amino acids.

Where is the primary place where secretion happens. What is its purpose?

The DCT and the PCT. To fine tune blood pH and electrolyte balance.

During reabsorption and secretion, substances are exchanged between the renal tube and…

 Peritubular capillaries.

(The renal tube is the ascending and descending loop of Henle)

What is the general flow of Blood?

Renal artery → afferent arteriole → glomerulus → efferent arteriole → peritubular/vasa recta → renal vein

What is the general flow of filtrate?

Bowman's capsule → PCT → Loop of Henle → DCT → collecting duct → renal pelvis → ureter

In reabsorption what is the process where water follows NA?

Osmosis

What 2 factors affect reabsorption?

Quantity of substance of filtrate

Rate of flow (Slow=more absorption, vice versa)

Examples of things that are secreted out.

Hydrogen Ions, potassium, drugs

What compound is Urine mostly?

Nitrogen-based including urea (broken down urea acids) - dark yellow means more solute in the filtrate.

What are some things filtered out of blood?

NaCl, water, vitamins, glucose, etc…

Why are red blood cells and large proteins (like albumin) NOT typically found in the filtrate after filtration?

To large to be filtered so they do not enter

If your body did not perform reabsorption, you would lose about ___ liters of fluid a day. List three vital substances the body must reabsorb to maintain homeostasis.

180 liters.  Glucose b. Water c. Amino acids

Which process is considered "passive" because it relies on blood pressure rather than metabolic energy (ATP)?

Filtration because it uses blood pressure to move substances.

What process would remove H+ from blood if it was too acidic.

Secretion

Glomerulus to Bowman's Capsule: Blood pressure forces water and small solutes (like glucose and urea) across the capillary wall into the nephron. This is…

Filtration

In the ____, nearly 100% of the glucose that entered the filtrate is moved back into the peritubular capillaries. This is..

PCT, Reabsorption

To help regulate blood pH, the ____ actively moves H+ ions from the blood into the tubular fluid. This is…

DCT, secretion.

Distal convoluted tubule (DCT), Secretion.

As filtrate travels down the ___, water moves out of the tubule and back into the bloodstream. This is

Descending Loop of Henle/renal tubule. Reabsorption

 Small molecules, regardless of whether they are "good" or "waste," are pushed out of the blood in the ____ based primarily on size. This is

Renal corpuscle (Glomerulus/ Bowman’s capsule). Filtration

Penicillin or other medications are often moved from the ____ into the renal tubule to be excreted. This is

Peritubular capillaries, secretion.

These building blocks of proteins are reclaimed from the filtrate in the ___ so they are not lost in the urine. This is

PCT, Reabsorption.

Under the influence of aldosterone, extra potassium is moved from the blood into ____. This is

the collecting duct, secretion

The very first process in urine formation where ____ is separated from blood cells and large proteins. This is

Plasma. Filtration

In the ______, sodium and chloride are moved out of the tubule to help maintain the medullary osmotic gradient. This is

Ascending limb. Reabsorption

Which typically has a larger diameter, the afferent or efferent arteriole?

Afferent is wider. The efferent restricts the exit, making the glomerulus force out fluid and solutes. Keeps glomerulus pressure high.

Which is permeable (allow to pass through) to Na, the descending or ascending loop of Henle?

The ascending loop

 In which of the following is the majority of reabsorption done, the PCT, loop of Henle, or DCT?

PCT

Are large proteins filtered in the Bowman’s capsule?

No, large proteins are usually reabsorbed into the PCT

Which kidney sits lower and why?

Right side is lower, it gives space for the liver.

Which kidney is generally a little bit heavier than the other?

Left, about 10g heavier.

Label

Check.

How much blood does each kidney filter per day?

120-150

How much urine is produced per day?

1-2 quarts

How much urine can a bladder hold?

1.5-2 cups

Do you have voluntary control of the internal or external urethral sphincter

External

What does the descending tube do?

Rebabsorbtion of water mostly

What does the ascending tube do?

Absorption of Na+ mostly.

Job of Pct

reabsorbs most water..

Job of DCT

reabsorption and secretion of ions