04-27-07, Anatomy Physiology Urology test review

The proximal convoluted tubule (PCT) assists in H₂O recover (75% is going to be recovered at the PCT).

The distal convoluted tubule (DCT) secretes toxins that are still in the blood that are not filtered out in the glomerulus. The distal convoluted tubule is the place of the nephron where toxins are filtered into the filtrate.

There are two main processes that occur in the urinary system. The first one is filtration and the second is reabsorption. Where does filtration occur? The process of urological filtration occurs at the glomerulus and occurs into the Bowman's capsule, which captures the filtrate. The glomerulus is where filtration is going to occur.

The reabsorption processes includes the proximal convoluted tubule and the Loop of Henle (which functions to take out water and salts from the urine).

Compare and contrast osmosis and active transport. Osmosis is the movement of molecules from areas of higher concentration to lower concentration, specifically water molecules. Osmosis is just water-based diffusion. It is specifically the movement of water from an area of high concentration to an area with less water concentration. Active transport is the movement of molecules, but from an area of high concentration to an area of low concentration and is against the concentration gradient (and so it requires energy and integral proteins to help change shape and so on). Active transport is not the movement of water.

What materials make up filtrate? There's water, urea, glucose, salts, amino acids, vitamins. The filtrate is made up of water, urea, glucose, salts, amino acids and vitamins. There's water, vitamin, amino acids, glucose, urea, and salts. That's vitamins, amino acids, urea, salts, water, and glucose.

What materials make up blood? Plasma, erythrocytes, leukocytes, thrombocytes, proteins, etc. Blood will have the most stuff in it. Filtrate (before reabsorption) and urine (after reabsorption) will have even least stuff. Urine should have no glucose.

Urine will not have glucose because glucose is reabsorbed into the blood stream at the cites of reabsorption. Urine will have the least things in it since it is the end product. Urine has water, urea, excess salts, and pretty much anything that the body has too much of. Urine is going to have the main component of urea, the nitrogen-based compound thanks to all of the metabolic activities in the body.

Where are the remaining materials secreted? The rest of the materials are secreted in the distal convoluted tubule, which secretes toxins that are too large to be filtered through the glomerulus but are going to, when they get close, there will be an active transport mechanism that will force the large toxins into the distal convoluted tubule and eventually into the filtrate and into the urine.

After the distal convoluted tubule you have the collecting duct which goes straight to the ureter and down to the bladder to be eventually expelled through the urethra which is controlled by two main sphincters (one is voluntary, the other is involuntary - the one that is close to the oxygen-exposed environment is going to be the one that is voluntary).

List the structures that water would go through, start after the renal artery has delivered the water to the arterioles. Arterioles are delivering the blood to the glomerulus. The renal artery branches into the kidney and starts to deliver the blood at the glomerulus sites on the nephrons.

The Bowman's capsule surrounds the glomerulus. It is like a cup that holds the glomerulus inside. It is ready to receive the filtrate, and it goes through the glomerulus, and the glomerulus is this giant series of capillaries (or parallel circuit, or something like that).

Glomerulus -> Bowman's capsule -> proximal convoluted tubule -> Loop of Henle -> distal convoluted tubule -> collecting tubule -> calyx -> renal pelvis -> ureter -> bladder -> urethra -> internal sphincter -> external sphincter (include these sphincters for extra points)

The calyx are like little tiny strands of tubules that are going to be collecting the waste material and transporting it out to the renal pelvis.

Looks like we are not going to be having the test today, then, there is a large lack of information here.

04-27-07, 2^nd period anatomy and physiology notes for the test since we are obviously not prepared for the test that was scheduled for today

What happens in the glomerulus? Filtration occurs in the glomerulus. Think of it as a fine mesh where things are going to be forced through. Anything that is too large, will not be forced through the glomerulus. Capillaries run throughout the entire nephron, so there's a reason why the distal convoluted tubule is going to be able to filter out toxins from the blood. So even though there is no physical connection that we can see in the diagram there, there's definitely a way that the distal convoluted tubule is going to get the bigger toxins.

Anything that gets through the glomerulus is going to be collected by the Bowman's capsule. Anything that gets through the glomerulus is going to be captured by the Browman's capsule. Then it continues to go through the system, such as at the proximal convoluted tubule. The Bowman's capsule captures the filtrate.

The proximal convoluted tubule acts in reabsorption. The proximal convoluted tubule reabsorbs 75% of the H₂O volume going through the PCT of the nephron unit of the kidney. The proximal convoluted tubule absorbs glucose back into the blood stream of the body. Also, the PCT absorbs glucose, sodium cations (Na⁺) and amino acids. One of these goes via active transport, another does piggybacking passive transport, etc. They're mostly passively transported across the PCT to the capillaries.

We do not want to get rid of glucose, because glucose is what we need to run cellular respiration, so you don't want to get rid of it, you want to hang on to it as much as possible. So once glucose hits the PCT, it's going to be reabsorbed back into the blood stream.

Strangely enough, some urea is reabsorbed into the blood stream. (Maybe it's because the cells in the kidney also produce urea, so they have to go somewhere too, or something like that.)

At the Loop of Henle, we are absorbing more water, sodium (Na⁺), and there is secretion of urea.

At the distal convoluted tubule, we are still reabsorbing water (H₂O) and sodium cations (Na⁺) which is pretty much something that is happening the whole time. Secreting wastes and toxins, and the hydronium cation back into the blood. This allows for the hydrogen ions to be dumped into the blood to make sure that the pH level is within its limits in order for the cells of the human body to survive (there's also some other pieces of information about the immune system and raising pH and temperatures and so on to kill foreign materials, invaders, microbes, viruses, etc.).

When it is reabsorbed, that means that the filtrate is going back into the body somewhat. Any time that you see the word “secrete” in these diagrams, secrete means that you've got stuff going into the nephron's pathway from the glomerulus, Bowman's capsule, PCT, Loop of Henle, DCT, collecting tubule, etc.

All of the collecting tubules from the nephrons move down to each calyx at the pointy tip of each medulla pyramid, and then they move to the renal pelvis and down through the ureter.