La fiscalidad por litro de alcohol puro según bebidas

About 99% of the fluid is reabsorbed 

Even though the filtrate has lots of small molecules like glucose, amino acids and bicarbonate ions, the urine has basically no protein, glucose or bicarbonate. ○ Blood goes in  Afferent arteriole ○

This is the filtrate making machine 

Its what does the filtration 

Makes filtrate 

Renal corpuscle ○

Makes filtrate into urine 

Where the peritubular capillaries reabsorb some of the stuff in the renal tubules □

This is pretty much the blood taking back the good stuff from the capillaries □

Reabsorption 

Of material from the blood in the peritubular capillaries to the tubule □

This is pretty much the blood getting rid of the stuff that wasn’t initially filtered out by the corpuscle □

This is of things we don’t want … like poisons and drugs etx. □

Secretion 

Renal tubule ○

Collects and concentrates the urine 

Is secretion here and not in the tubule??? 

Collecting duct ○

Blood goes out 

Efferent arteriole ○

Absorb and secrete after filtration is already done … interacts with the renal tubule  Peritubular capillaries ○ ○ Big Picture •

This is on the outside 

Afferent + efferent arteriorles comes through this 

This is between its visceral and parietal layer □

Notice that the glomerular capsule is a continuous layer of tissue with the glomerular capillaries jammed into the center. □

This is where the filtrate is pushed to after the blood is filtered □

Glomerular capsule space 

Glomerular capsule ○

Have capillaries of the glomerulus (covered by the visceral layer of the glomerular capsule) 

Glomerulus ○

Is connected to the glomerular capsular space … filtrate is pushed through that 

Proximal convoluted tubule ○

Distal convoluted tubule ○

Just tastes the filtrate and then controls the amount of blood coming in to make sure we are making the right amount of filtrate 

Juxtaglomerular appartus ○

This is on the afferent arteriole 

This constricts the arteriole when ur in symp mode … so that u don’t make urine then  Sympathetic nerve ○ Renal Corpuscle • Glomerular capsule ○

Fenestrated capillary wall 

Basal lamina 

Make up the visceral layer of the glomerular capsule … sit outside the capillary □ Podocyte  Filtration slits □ Pedicel  Glomerulas ○ Microanatomy •

Has foot processes (pedicels)  Podoctye ○ Steps ○ Filtration •

From the glomerular capillary to the capsular space 

Blood has to go through first the capillary fenestrations and then the basal lamina 

After that, the blood has to get through the filtration slits 

Glomerulus → Capillary fenestrations → Basal lamina → Fesenstration slits → Capsular space □

Path  ○

All small molecules can pass into the capsular space and form filtrate, but large molecules (> albumin size) cannot and stayin the blood 

Key ○

○

Have to have filtration pressure to make filtrate 

Have blood pressure pushing blood out of the glomerular capillaries 

This is positive pressure 

Blood hydrostatic pressure □

Out 

Hydrostatic pressure of the fluid already in the capsule 

Capsular hydrostatic pressure □

Proteins want fluid to come back into the blood capillary 

Blood osmotic pressure □

In 

Net pressure of 10 mm HG pushing the fluid out of the capillaries □

This determines GFR (glomerular filtration rate) □

Sum 

Net Filtration Pressure ○

Maybe want to tweak the GFR based on the situation 

Decrease when dehydrated … increased after drinking a lot 

Introduction ○

Call this autoregulation because the mechanisms are internal to the kidney 

The kidney itself can act to alter the GFR- ○

By changing the blood pressure in the glomerulus 

Then it is because the blood pressure in the glomerulus is too high. □

Seems counter-intuitive cause you'd think it would relax if the pressure is too high … im thinking it’s the afferent arteriole that contricts and therefore its the capillaries that face less pressure?



Remedy for this is to have the afferent arteriole constrict so less blood flows to the glomerular capillaries under less pre ssure and the GFR goes down.

□

If the GFR is too high 

The opposite occurs when GFR is too low. 

The filtration rate is easily altered: ○

This changes in the afferent arteriole can be done by the kidney itself by either the myogenic mechanism or tubuloglomerular feedback ○

They don’t like to stretch … when they get stretched … they contract □

So when there is too much blood … its constricts and decreases GFR □

Smooth muscle of the afferent arteriole itself detects the increase in pressure and responds by constricting 

Smooth muscle always responds to stretching by contracting against the stretch. □

This is true of all smooth muscle 

The Myogenic Mechanism ○

Summary: if the juxta sees too much filtrate, it causes contraction of the afferent arteriole by inhibiting NO (stops dilatio n) □

In this mechanism the macula densa of the juxtaglomerular apparatus detects high amounts of filtrate flow (i.e., lots of water, Na+ and Cl- flowing past) and this causes inhibition of nitric oxide release in the juxtaglomerular apparatus which inhibits afferent arteriole dilation 

This is a bit confusing because the filtrate can be quite dilute when there is lots of filtrate production which makes it loo k like the low ionic concentration is driving the constriction. However the combination of the high flow with even modest levels of ions wil l lead to quite a high delivery of ions to the macula densa.

□ Note: 

By decreasing the GFR the flow rate of filtrate will decrease which allows more water and ions to be removed. 

Tubuloglomerular Feedback ○

The GFR can also be altered by other neural and hormonal mechanisms as shown on the next slides … Renal Autoregulation + GFR (glomerular filtration rate)

The GFR can also be altered by other neural and hormonal mechanisms as shown on the next slides … ○

Increases GFR □

Distension of the heart leads to the release of ANP 

The ANP causes relaxation of the cells (mesangial cells) between the glomerular capillaries 

Basically increase the holes between the capillaries ◊

The glomerular capillaries become more spread out so more filtration occurs 

More filtrate ◊

More urine ◊

Less volume in the blood ◊

Result 

Once the blood volume goes down the pressure in the heart decreases and ANP is no longer secreted  Steps □ ANP  Decreases GFR □

So the high BP although normally would increase GFR … but its also constricting the afferent arteriole so the high BP doesn’t effect GFR in terms of increasing it



Therefore increases your bodies overall BP but decreases amount of blood going to the glomerulus 

But it increases BP … but it also constricts afferent arteriole □

If there is low BP … kidney wants to reduce urine production cause it doesn’t want you to go into hypovolemic shock … isnt going to steal fluid for urine when you don’t even have enough blood



Not only does the tubuloglomerular apparatus business but also makes renin when there is low BP or symp innervation ◊

Juxtaglomerular apparatus 

Eventually angiotensinogen II is made  Angiotensin II and BP □ Angiotensin II  Hormonal Regulation of GFR ○

These are a1receptors

□

Stimulation = contraction □

Symp branch has inputs to the muscular wall of the afferent arteriole 

This decrease blood hydrostatic pressure and therefore filtration □

Decreases blood going to the glomerulus 

Also does this in case your fright and flight doesn’t work and you get hurt … need blood and not urine at that point □

Increases spare blood for muscles and makes it so there is no urine 

Neural Regulation of GFR ○

Afferent + efferent arteriole + renal corpuscle + renal tubule + collecting duct + peritubular capillaries 

e.g., glucose, amino acids, bicarbonate ion 

Some completely reabsorbed □

e.g., water, sodium, potassium, chloride etc. 

Some regulated and thus is partially reabsorbed □

e.g., urea, creatinine, drugs and drug metabolite 

Some excreted as waste □

Filtrate has lots of stuff … what happens to it: 

The nephron ○

180 L in filtrate but 1-2 liters of urine □

Water 

162 g in the filtrate but none in the urine. □

Gets taken out completely □

Glucose 

2.0 g in the filtrate 0.1 g excreted □

Protein 

570 g in the filtrate but 4 g excreted □

Na 

8.5 g in filtrate and 0.8 g in urine □

Uric acid 

1.6 g in filtrate and 1.6 g in the urine □

Completely excreted □

Can be used to see how well kidneys are working … □

Creatinine 

Beyond the renal corpuscle the nephron is completely consumed with these processes 

Balance ○

Running along providing blood pressure for the system □

In between the lobules of the kidneys 

Comes of the arcuate 

From these come off the afferent arterioles  Interlobular artery □ Arcuate artery  Straight vessel □

Run along the loop of Henle □

These are what connect to the efferent arterioles and take that blood out of the system □

Vasa Recta 

This is where the blood leaves □

Do the peritubular capillaries drain to this as well??? □ Arcuate vein  Renal Tubule ○ Requires energy  Active transport □

Involves chemicals following their electrochemical gradients. 

Passively □

Reabsorption can occur by either by: 

The movement of water is by osmosis (a passive mechanism by which water follows its concentration gradient through a semipermeable membrane)



What drives osmosis is the movement of the solutes from the tubules to the interstitial fluid which often requires energy 

Osmosis □

Much of the obligatory reabsorption of water will occur in the proximal convoluted tubule and descending loop of Henle because these areas have tubules which are permeable to water.

◊

About 90% of water reabsorption is obligatory which is to say that it is dragged along by the solutes being moved from tubules to interstitial fluid.



The facultative water reabsorption is under control of the hormone called Antidiuretic Hormone (ADH) which makes the cells in the collecting duct permeable to water and thus water can leave the ducts and go back into the interstitial fluid and then enter the peritubular capillaries

◊

The last 10% of water reabsorption is facultative which is to say it can increase or decrease depending on the amount require d by the body



Water reabsorption □

Movement of water will all be by osmosis. This osmosis is linked to the passive reabsorption (diffusion) of a number of ions as well as the waste product urea.



About 65% of the water has also been reabsorbed. ◊

By far the most active area for reabsorption is the proximal convoluted tubule. By the end of the proximal convoluted tubule 100% of most of the organic solutes have been reabsorbed.



Sodium leaves the tubule to the capillaries ◊

Water follows into the capillaries ◊

Summary 

Osmosis and the Proximal Convoluted Tubule (PCT) □

Water 

Reabsorption of Solutes and Water ○

Kidneys •

Renal Function + Tubular Phys

In document Departamento de Aduanas e Impuestos Especiales 3. IMPUESTOS SOBRE EL ALCOHOL Y BEBIDAS ALCOHÓLICAS (página 79-83)