CSN Bio 224 Aulner Exam 4 - 2019

Kidneys

Very efficient and Solid Organ

Nephron

Functional Unity of the Kidneys

Kidneys Weight & Length

130 grams or less and 5 inches

What organs make up the Urinary System

Kidneys, Ureters, Urethra and Urinary Bladder

What is the main function of the Urinary System?

Fluid Homeostasis

What are the other functions of the Urinary System?

To regulate PH, and Blood pressure, composition, concentration and volume (VCCPP).

What are the secondary functions of the kidneys?

Making Erythropoieten (EPO) - a hormone and Renin - an enzyme.

What is the function of Erythropoieten?

Stimulates the bone marrow to produce more RBC's and elimination & excretion of waste.

What is the function of Renin?

Regulates Blood Pressure.

What is a by-product of fluid homeostasis?

Urine.

Up to what percentage of kidney loss will not affect me?

Up to 50%

Up to what percentage of kidney loss will not show symptoms?

Up to 75%

Up to what percentage of kidney loss begins to show symptoms?

75% or more begins to show symptoms.

What percentage of our kidney will we still be able to function with?

25%

Death happens within how many days after renal failure

Days to weeks.

Where is the kidney located? Retroperitoneau - behind the peritoneal T12 - L3.

Where is kidney surgery usually performed?

Usually completed on the side or back of a human.

How do you palpate the kidneys?

By placing one hand under the right flank, and the other on the right coastal margin (top).

What surrounds the kidneys?

The kidneys are surrounded by adipose aka perirenal fat and held up by C.T. Fibers.

Define Ptosis.

The slumping or sliding down of the kidney. Typically due to metabolic/weight disorders such as anorexia, bulimia etc. It can pinch off veins supplying ureters w/blood and lead to death.

What is the Kidney make-up?

Capsule, cortex and medulla (outer to inner). The medulla is 5 to 8 pyramid shaped structures.

Where does urine come out from on the kidney?

The tip of the medulla is called the papilla. This is where urine comes out from.

What is the blood rotation through the kidneys?

Pyramid to cortex to back

What is the Calyx?

Urine canals connected to pyramids (Minor and Major Calyx).

What is the Hilum?

Dent in organs where tubes come in/out of.

Where is the of the kidneys located?

@ top of ureter, but in same location as pelvis

What are the names of the 3 blood organs?

Kidney's, Spleen and Liver

What is the blood volume of kidney's at all times?

25%

How much blood goes through the kidneys per day?

1800 Liters of blood.

How much blood does the body hold @ one time?

4 to 6 liters

Which organ has the highest velocity (speed) of blood going through it?

Kidneys

What is the pathway of blood through the kidneys?

Renal artery-segmental artery-Interlobar Artery-Arcuate Artery-Interlobular artery (corticaladiate artery)-Afferent Arteriole-Glomerulus-Efferent Arteriole-Pertibular Capillaries-Vasa Recta-Interlobular vein (cortical Radiate radiate vein) RSIAIAGEPVI

What are Nephrons Responsible for?

Filtration, Re-absorption and Secretion.

Where is a place of reabsorption?

Proximal Convulated Tubule - Reabsorption w/little secretion Rs

How many nephrons are in both kidneys combined?

2.6 million

What do the Juxtamedullary Nephrons do?

Plays role in reabsoption. This accounts for 15% of all nephrons. The juxtamedullary Nephrons have loops of henle that extend deep into the medulla.

Describe the Cortical Nephrons and what they do.

They have loops of henle that do not extend deep into the medulla. This accounts for 85% of nephrons. They are located in the cortex.

BC + G =

Filtration

PCT = Rs

Re-absorption and a little secretion

LH (Loop of Henley) =

Reabsorption, Loop of Henley

DCT/CD =

Distal convulated tubule/collecting duct. Reabsoption and/or secretion (Variable depending on needs.

What does the glomerulus do?

It is a filtrated capillary bed that is EXTRA LEAKY

What are podocytes aka foot cells made of ?

Made of simple squamous epithelium.

What do podocytes aka foot cells do?

These cells cover glomerulus but are part of Bowman's Capsule. Spaces between podocytes are called filtration slits.

What is the BP in glomerulus?

50 millimeters of Mercury (Hg). This is relatively high BP for a capillary not for an artery.

What is the fluid BP of Bowmans Capsule?

10 millimeters of mercury (Hg)

What is the osmotic pressure of the Glomerulu?

30 mm hg. And osmotic pressure is pulling.

What is the formula for net filtration pressure?

add fluid pressure of 10 mmhg to osmotic pressure of 30 mmhg = 40 mmhg. (Which wins the push fight = filtratrion.) Filtration of 50 mmhg; 50-40 = 10 NFP.

What pressure do we need to keep filtration at?

50 mmhg

Which arteriole is larger in diameter the Afferent or Efferent?

Afferent.

How is pressure kept up?

As fluid moves into smaller hose towards efferent arte3riole, this keeps pressur up.

How are drugs classified?

Based on the increase or decrease of action potentials.

Does caffiene Increase or decrease the blood pressure AND why?

Increase. More filtration = more urine due to increased net filtration pressure.

What is the blood when it is in the glomerulus?

Blood Plasma.

What is blood in the Bowman's Capsule?

It becomes filtrate. (lipoproteins, clotting factors and unnecessary items stay behind.

How fast is the glomerulus filtration rate?

always expressed as milliliters per minute. 125 milliliters/min.

Where is filtrate made?

Bowmans capsule.

Where does reabsorption occur?

peritubular capillaries. Moving a molelcule for the filtrate back up to the peritubular capillary is reabsorption.

What are the main compononets of reabsorptions?

Sodium and Water

What is secretion?

Moving a molecule from the peritubular capillary to filtration via soduim pump is secretion

When does h2o follow sodium?

When it can. When cell membrane permeability permits. Cell membranes are selective permeability.

Does water like lipids?

No

What is the cell membrane made of?

Lipids. *keep this in mind w/water following sodium.

Does sodium co-transport?

Yes, this means it could be a sodium/gloucose pump or Na+/amino acids etc.

How do we reabsorb sodium?

By pumping water via following sodium if selective permeability allowed other molecules via co-transport.

Define counter-transport aka anti-transport.

Pumping of ions in different direction. Na+ pumps also counter-transport.

Define variations of a theme?

Sometime I pump something out, we can bring something in as well.

How much of Na+ and H20 are reabsorbed in the proximal convulated tubule?

65%

How much of Glucose (g), Amino Acids (aa) and other organics reabsorbed by co-transport w/Na?

100%

how much of the HCO-3 is reabsorbed out of the PCT

90%

How much Cl- is reabsorbed?

60%

Why do HCO-3 and CL- follow Na+?

Due to the opposite attractions

Do we expect Glucose, aa, and other organics in the urine? And if not, where are they pulled out?

No. As they are reabsorbed at 100% in the PCT.

What does it mean if we see glucose in the urine?

PCT is not fx or so much glucose in blood that the kidneys can not pull it all out.

What is the loop of henle use for?

The ringing out of excess water that was not already removed.

How does water flow through the PCT?

PCT-Descending limb of loop of henle-ascending limb of loop of henle-DCT.

is the ascending limb of the loop of henle permeable to water?

No.

Is the descending limb of the loop of henle permeable to water?

Yes

Is the descending or ascending limb of the loop of henle permeable to water?

Descending

How does the flow of molecules work at descending limb?

The more Na+ and Cl- pumped out of the ascending limb, the more H20 comes out of the descending limb.

What is this called? The more Na+ and Cl- pumped out of the ascending limb, the more H20 comes out of the descending limb.

Positive feedback mechanism.

Does this positive feedback mechanism ever reach equillibrium?

No. It does not have a stopping point.

Why does the feedback mechanism not reach equilibrium?

Constantly receiving new filtrate in and old filtrate going out AND pertiubular capillaries counter-current exchanger or counter current multiplier.

Define counter current exchange

Descending artery going down and ascending artery going up = trading of substances i/e. na+,cl- and h20

Define counter-current Multiplication

descending and ascending artery change in concentration.

Does concentration increase in ascending or descending limb and why?

In descending limb due to h20 being filtrated out.

Why would concentration decrease in the ascending limb?

Due to h20 coming in

Where does Urea cycling occur?

Loop of Henley

What is the Medulla mostly used for?

Collecting ducts

Flow of urea cycling

Juxtamedullary loop-interstitial fluid-loop of henley descending limb

Where does the first set of ringing out the towel occur?

PCT

Where does the second set of ringing out the towel occur?

Loop of henle

By the end of the loop of henle what percentage of Na+ and H20 has been absorbed?

25% more

By the end of the LH what percentage of Cl- has been reabsorbed?

35%

What percentage of Na+ and H20 is pulled out of PCT

65%

What percentage of Na+ and H20 filtrate is left when entering DCT/CD?

10%

Where is filtrate fine-tuned into urine?

DCT/CD; we may change Na+ or H20 @ this point if we want more na+ or h20 in the urine. We would update it here. Fine-tuners are hormones.

Define aquaporins

Water holes that allow water into the cell

Where is ADH - Antidiuretic hormone (water only) made?

Hypothalamus

Where is ADH released?

Posterior pituitary gland