Renal Flashcards by Zachary Schulz

What are the 5 functions of the kidney?

Regulation of Water
Removal of metabolic waste
Removal of foreign chemicals
Gluconeogenesis
Production of hormones/enzymes

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What are the 3 hormones/enzymes produced in the kidney?

EPO
Renin
Vitamin D precursor

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This is the structural unit of the kidney…..there are over 1,000,000.

Nephron

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What two things compose a neprhon?

Glomerulus

2. Renal capillaries

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The distal tubule is close to Bowman’s capsule and the afferent arteriole because it provides improved _______.

control

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The glomeruli have a surface area of 2100 square feet. decrease in 1/2 of this is consistent with ________ ____ _______.

Symptomatic renal failure

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Your kidneys filter __ gallons of fluid every day, and you reabsorb __% of it.

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Mammals (Humans) convert nitrogenous waste into less-toxic _____, which can be stored and dissolved in water.

Urea

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Because of this urea, there’s a certain amount of water we must lose in our urine each day. What is this reffered to as?

Obligatory water loss

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These are cells within Bowman’s capsule that aid in filtration.

Podocytes

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Describe the path blood takes through the glomerulus.

1, Plasma travels through the afferent arteriole

Into the glomerulus
plasma gets filtered through fenestrated capillaries, podocytes, and into Bowman’s capsule.
Out through the efferent arteriole

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The glomerulus also contains smooth muscle-like cells called ________ (“between the vessels”) cells.

Mesangial

These cells can contract to regulate the blood flow in the glomerulus.

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T/F: Fenestrated capillaries allow solute-rich fluid to pass through, including proteins.

False (Proteins can not pass through, proteinuria is BAD)

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Podocytes terminate in foot processes which surround the basement membrane of the glomerulus. The clefts between the foot processes are called ________ ____.

Filtration slits

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Filtration slits allow for what two things to pass through? What two things are too large to pass through.

Ions, Large molecules

Protein, blood cells

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What should you think if someone’s urine has proteins or blood cells in it?

Glomerular damage

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Can you name some things that might cause glomerular damage?

hypertension, trauma, autoimmune processes, tubular blockage causing a back-up

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Water and smaller molecule will move across the glomerular membrane and podocyte barrier until the concentrations are the ___ on both sides.

same

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What three things determine the rate a substance will diffuse across the membrane?

Concentration of the substance in the blood
Hydrostatic pressure in the glomerular capillary
Hydrostatic and oncotic pressure inside of Bowman’s capsule.

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If there was a “road block” in the proximal tubule, what effect would it have on diffusion in the glomerulus?

Slow it down

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These compose the majority of nephrons in the kidney and are the “hard-workers”.

Whare in the kidney are they primarily located?

Cortical Nephrons

Cortex

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These are composed of the Long loop of Henle, are involved in the concentration of urine, and composed about 15% of all nephrons.

Where in the kidney are they located?

Juxtamedullary Nephrons

Medulla

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Filtration occurs in the _______.

Re-absorption occurs primarily in the ________.

Secretion occurs primarily in the _________.

Glomerulus

Proximal tubules

Distal tubules

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Nephrons are associated with what 2 capillaries?

Glomerular and Peritubular

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Glomerular capillaries specialize in ___________ and are fed and drained by ___________.

filtration arterioles (Afferent/Efferent)

Pressure can be higher in the glomerular capillaries because of the arterioles, this allows for what?

The increased hydrostatic pressure forces more fluid out into Bowman's Capsule

Walk through the vasculature of a nephron.

Afferent arteriole --> Glomerular capillaries --> Efferent arterioles --> peritubular capillaries --> veins

Filtration is movement out of _______ _____ and into ______ _______.

Glomerular capillaries Bowman's capsule

Reabsorption is movement out of _______ _____ and into ______ _______.

the proximal tubule the peritubular capillary

Secretion is movement out of _______ _____ and into ______ _______.

the peritubular capillary the distal tubule

Filtration is a _______ process

passive

Why is it important to keep plasma proteins in the plasma during filtration? If plasma proteins leak out what would happen?

To maintain osmotic pressure Too much fluid would leak out into filtrate

What force makes filtration go? What force works against it?

Glomerular pressure (BP - hydrostatic pressure) Bowman's pressure (Osmotic pressure)

What happens if Bowman's pressure increases?

filtration would slow down or stop because the concentration gradient would be smaller

Is transport during reabsorption active or passive?

Both

T/F: Filtrate is the same as urine

False

Understand how to interpret the glucose graph.

SLIDE 27

Reabsorption occurs when moving from _____ to _____.

tubule to capillary

Secretion occurs when moving from _____ to _____.

capillary to tubule

The volume of plasma that is cleared of a substance in one minute is known as _____ _________.

Renal clearance

What is the equation for renal clearance

Concentration of a substance in the urine MULTIPLIED BY the rate of urine formation DIVIDED BY The concentration of the substance in the plasma

Renal clearance is used to calculate what lab value?

eGFR (estimated glomerular filtration rate)

What is the most common substance found in the plasma and urine used to calculate eGFR?

Creatinine

Renal clearance is often calculated using what process? (THINK: Urine collection over what period of time)

24 hour urine sample

What THREE things affect eGFR

1. Amount of filtration surface available (Varies with age, gender, ethnicity) 2. Filtration membrane permeability and net filtration pressure (Varies with age, gender, ethnicity) 3. Blood pressure/blood flow

GFR is ______ proportional to the filtration pressure.

Directly

An increase in systemic BP means a ______ in GFR and vise versa.

increase

If blood flow is decreased afferently through vasoconstriction then blood pressure in the glomerular capillaries would ______ which would cause GFR to _______.

Decrease Decrease

If blood flow is decreased efferently through vasoconstriction then blood pressure in the glomerular capillaries would ______ which would cause GFR to _______.

Increase Increase

If blood flow is increased efferently through vasodilation then blood pressure in the glomerular capillaries would ______ which would cause GFR to _______.

decrease decrease

If blood flow is increased afferently through vasodilation then blood pressure in the glomerular capillaries would ______ which would cause GFR to _______.

Increase Increase

Understand how your kidneys control GFR when there is NA+ and Water lose from Diarrhea.

Na+ and Water lose from diarrhea lowers your plasma volume and venous pressure. This in turn causes a drop in atrial pressure as well. The drop in arterial and venous pressure triggers the SNS The SNS then tells your kidneys to constrict the afferent arterioles. This vasoconstriction slows down the filtration rate and GFR. This in turn slows down the excretion of Na+ and Water

In a perfect world, we take in and excrete ______ mL of water every day. What would cause and in the amount of water we take in? What would cause an increase in the amount of water that is excreted?

2850 Water intoxication, edema Sweating, fevers, emesis, diarrhea, diuretics

In a perfect world, we take in and excrete ______ g of Na+ every day. What would cause and in the amount of Na+ we take in? What would cause an increase in the amount of Na+ that is excreted?

8.50 Increased sodium intake (Diet) Sweating, emesis, diarrhea

Na+ is reabsorbed through _____ transport in all tubules except the _______ loop of Henle.

Active Descending

Water is reabsorbed through ______, which is ______ diffusion. However, it is determined by the movement of Na+ and the presence of water channels called _________.

osmosis passive aquaporins

Vasopresin is stored in the _______ pituitary.

Posterior

Vasopresin is produced in the ________ and stored in the posterior pituitary.

Hypothalamus

What triggers the release of vasopressin?

Elevated serum osmolarity (which is detected by osmoreceptors near the hypothalamus)

Na+ reabsorption is always ______ transport.

Active (Na+/K+ pump)

Walk through the process of Na+ transport from the tubular lumen to the interstitial space

As the concentration of Na+ in the tubular lumen increases it passively diffuses into the proximal tubular cells During this time it is also bringing another substance (ie: glucose) into the cell through co- transport As the concentration of Na+ increases inside the cell, the Na+/K+ pump actively transport Na+ into the interstitial space to maintain the concentration gradient

The carotiod and atria also have _____________, which detect a ________ in BP and release vasopressin.

Baroreceptors Decrease

What is the term for large/increased urine flow from any cause?

Diuresis

SIADH is caused by too much what? What would symptoms of SIADH be? What would the serum Na+ level be in someone with SIADH?

ADH (Vasopressin) Extreme thirst, large dilute volumes of urine, hypotension, dry skin/mouth Elevated serum Na+ levels

In the loop of Henle, the descending portion of the loop is impermeable to _____ but freely permeable to ______.

Solute Water

In the loop of Henle, the ascending portion of the loop is impermeable to ______ but freely permeable to ______.

Water Solute

Understand osmolarity changes from the descending loop of Henle, to the descending loop of henle, and down through the medullary collecting duct.

As fluid starts down the descending loop, the osmalrity is about 300 as it is fairly diluted Water passively diffuses out making the fluid more concentrated. At the bottom the osmolarity is 1400 As fluid moves up the ascending loop, solutes (NaCl) start to diffuse out of the tubule. This causes the fluid to become diluted again. At the top, the osmolarity is around 80. As the fluid makes its way down the medullary collect duct, water again diffuses out of the tubule, making the fluid more concentrated. Urea is used at this time to maintain pressure gradients. At the bottom, the osmolarity is 1400.

________ is a key controller in sodium reabsorption.

Aldosterone

Aldosterone ________ Na+ reabsorption.

Increases

What hormone is secreted by Juxtamedullary cells on the afferent arteriole? What additional function do JG cells have?

Renin Control blood flow into the glomerular capillaries

JG cells are ___receptors. They release renin when there is a ________ in BP.

Baro Decrease

Renin stimulates the release of __________, which stimulates the release of ___________.

angiotensin aldosterone

Macula densa are located in the ________ tubule.

distal

Macula densa are _____receptors which respond to changes in NaCL content of the filtrate.

chemo

Renin releases by the kidneys interacts with angiotensinogen to form ____. This then interacts with an enzyme in the blood stream to form ____.

AT1 AT2

AT2 works with the CV system to increase blood pressure by __________. AT2 works with the kidneys to increase BP by retaining ____ and ______.

Vasoconstriction Na+ and Water

Aldosterone works by retaining ____ in the blood stream and excreting __ in the urine. If you had too much aldosterone, what would happen to you serum K+ levels?

Na+ K+ They would be super low

What two conditions are diuretics used to treat? Which tubule to they primarily work at?

HTN, Edema, CHF Distal Tubule

What hormone is produced at the atria? What does it contribute to?

ANP Na+ Loss

H+ can increase causing acidosis from what? (Name two)

Increased H+ production from CO2 Bicarbonate loss from diarrhea or in the urine

H+ can decrease causing alkalosis from what? (Name two)

Increased H+ utilization H+ loss in vomit/urine Hyperventilation

To increase blood pH, you ____ ___ more bicarb.

Hold on

To decrease blood pH, you ___ ___ ___ more bicarb.

Get rid of

Is it a respiratory/metabolic acidosis/alkalosis..... 1. Blood pH is decreased because of an increase in respiratory CO2 2. Blood pH is increased because of a non-respiratory decrease in acid content. 3. Blood pH is decreased because of a non-respiratory increase in acid content 4. Blood pH is increased because of a drop in respiratory CO2.

1. Respiratory acidosis 2. Metabolic alkalosis 3. Metabolic acidosis 4. Respiratory alkalosis

This woman is diabetic and her blood glucose is quite high. She is is in diabetic ketoacidosis (her blood pH has dropped because of the ketones her body is making). Her arterial blood pH is 7.1. Is she in acidosis or alkalosis? Is it metabolic or respiratory? What will happen to her ventilation?

Metabolic acidosis Increase

A man has been throwing up for 3 days, depleting him of his H+ ions. Is he in an acidosis or alkalosis? Is it respiratory of metabolic? What will happen to his respiratory rate?

Metabolic alkalosis Decrease