Renal Therapeutics I Flashcards by Amy Lockyer

List the 2 major roles of the kidneys

Homeostatic regulation of water and inorganic ion balance

Removal of metabolic waste products and foreign chemicals from the blood and their excretion in the urine

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Label the kidney

[Labelled kidney]

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What is a nephron?

The functional unit of the kidney

Loops between the cortex and the medulla

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List 4 essential secretions (from blood to tubular fluid)

Renin
Vitamin D3
Prostaglandins
Erythroprotein

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List the 3 processes involved in the elaboration of the urine complex

Filtration
Reabsorption
Secretion

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Explain the process of filtration during the elabortion of the urine complex

Occurs in the glomerulus under very high pressure
Forms the filtrate, which then enters the tubules
Then called tubular fluid

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Explain the process of reabsorption during the elaboration of the urine complex

Movement from tubular fluid to blood

Transcellular or paracellular

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Explain the process of secretion during the elaboration of the urine complex

Movement of molecules from blood to tubular fluid

Transcellular or paracellular

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Why are the 3 process which occur during the elaboration of the urine complex so important?

In order to conserve electrolytes and regulate osmolality

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Explain the route the blood takes in order to pass the Bowman’s capsule

Afferent arteriole

-> Efferent arteriole
-> Peritubular capillary

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Where are molecules reabsorbed to from the nephron?

Peritubular capillary

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Where are molecules secreted from the blood and into the nephron?

Peritubular capillary

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How does the kidney regulate blood pressure?

By controlling how much water is removed from the bloodstream and excreted as urine (during reabsorption)

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What happens to the electrolytes present in the tubular fluid at the Loop of Henle?

Descending loop = H2O passes out via passive diffusion (tubular fluid becomes more concentrated compared to its environment)
Ascending loop = NaCl passively and then actively transported out, little water permeability

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What happens to electrolytes present in the tubular fluid at the collecting duct?

Water and urea passively pass out of the nephron

The urea passes back into the descending Loop of Henle

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List 3 molecules which can pass into the tubular fluid

Glucose
Water
Urea

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Where is renin produced?

Kidney

Protease/enzyme

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Where is angiotensinogen produced?

Liver

Protein

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What role does renin play in the renin-angiotensin-aldosterone system (RAAS)?

Renin cleaves angiotensinogen into angiotensin I

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Explain the processes which occur in the renin-angiotensin-aldosterone system (RAAS)

The kidney produces the enzyme renin which cleaves angiotensinogen made in the liver
This produces angiotensin I
Angiotensin I is cleaved by ACE (protease) to produce angiotensin II

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What is ACE?

Angiotensin-converting enzyme

Protease

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Where is ACE produced?

Either the kidney or the lungs

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What effects can angiotensin II have on the body?

The arterioles - vasoconstriction to increase/maintain BP
Pituitary gland - ADH secretion affecting H2O absorption at the collecting duct
Sympathetic activity
Causes the adrenal gland to secrete aldosterone

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What is aldosterone

Steroid hormone
Controls BP
Causes water to be reabsorbed as well as sodium = increased blood volume = increased BP

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What is the role of ADH/vasopressin?

It regulates plasma volume by controlling how much water is secreted/reabsorbed in the kidneys ADH/vasopressin makes the distal convoluted tubule and collecting duct more permeable to water (excretes less)

How is ADH/vasopressin released?

Pre-optic nerve detects drop in BP from losing too much water Osmoreceptors in the hypothalamus detect changes in the osmotic pressure So it releases ADH to keep more water in the body

What is ADH also known as?

Vasopressin

What does ADH stand for?

Anti-diuretic hormone

Where is ADH produced?

Hypothalamus

Where is ADH released?

Posterior pituitary gland

What do osmoreceptors do?

Detect changes in osmotic pressue

What is Diabetes insipidus caused by?

Caused by the inability of the kidney to conserve water | Therefore frequent urination and extreme thirst

What is Central diabetes insipidus caused by?

Caused by lack of ADH due to damage of hypothalamus or result of surgery

What is Nephrogenic diabetes insipidus caused by?

Kidneys fail to respond to ADH

Name the 2 types of diabetes insipidus

Central diabetes insipidus | Nephrogenic diabetes insipidus

What are micturition abnormalities?

Problems with the process of passing urine

What is normally the root of micturition abnormalities?

The lower urinary tract

What do abnormalities in urine volume usually imply?

A more serious cause

List 5 symptoms of micturition abnormalities

``` Dysuria = painful Hesitation = difficulty starting Frequency Incontinence = difficulty stopping Noctuia = frequency at night ```

List 5 possible causes of these micturition abnormalities

``` UTI/inflammation Outflow obstruction Heart failure Diabetes Polyuria = production of an abnormally large amount of urine ```

List 3 symptoms of urine volume abnormalities

``` Polyuria = production of an abnormally large amount of urine Oliguria = production of an abnormally small amount of urine Anuria = failure of the kidneys to produce urine ```

List 4 possible causes of urine volume abnormalities

``` Diet Climate Renal tubular disease (RTD) Diabetes (mellitus or insipidus) Chronic renal failure (CRF) ```

List 3 systemic symptoms of renal impairment

Fluid and electrolyte imbalances Osmotic imbalance can cause neurological issues Uraemia = high level of blood urea --> lethargy, nausea, vomiting

Name 3 measurements which can be used for urine analysis

Specific gravity = concentration of the urine pH Abnormal constituents

List 5 abnormal constituents which could be found in the urine and what this could indicate

Proteins (proteinuria) = glomerular diease Blood (haematuria) = infection, inflammation, tumour Haemoglobin = haemolytic anaemia Pus (pyuria) = renal or urinary tract infection Crystals (crystalluria) = depends on crystals

What is the rate of filtration?

Initial filtrattion of compounds from the bloodstream to the collecting duct Indication for efficacy of kidney Difficult to measure

What is Clearance?

Hypothetical volume of blood from which a substance would be completely removed by filtration in 1 minute

Which 3 pieces of information are required in order to calculate the rate of filtration and clearance?

Plasma concentration of substance Urine flow rate (over 24 hours) Urine concentration of substance

List 4 things which may result from problems with kidney function

Loss of nutrients from the body Failure to remove toxins Affect drug treatments Affect BP

What is GFR?

Glomerular filtration rate Used to measure clearance Dependent on the net filtration pressure, glomerular surface and the permeability if the glomerular membrane

Describe the relationship between plasma clearance and GFR and the implications of this

Plasma clearance should = GFR | Plasma clearance GFR = substance filtered and secreted but not reabsorbed

List 3 factors that must apply to a substance if its renal clearance is to equal the GFR

The substance is: Freely filtered from the blood capillaries into the Bowman's capsule Neither absorbed or secreted by the tubules Has no overt effect on renal metabolism

Which substance is used to calculate GFR?

Creatinine

What is the equation used to calculate GFR from creatinine?

``` CrCl = [F(140-age) x weight] /SrCr F = 1.04 in females, 1.23 in men ```

What is RPF?

Renal plasma flow | The volume of blood plasma delivered to the kidneys oer unit time

What is the relationship between PAH and RPF?

PAH clearance is used to estimate RPF This is because PAH enters via glomerular filtration and is secreted but not reabsorbed Therefore clearance = RPF

What is filtration fraction?

The fraction of plasma through the kidney which is filtered | = GFR/RPF

List 6 things that should be monitored in order to estimate renal function

``` Creatinine Plasma sodium Plasma bicarbonate Plasma calcium Plasma phosphate pH ```

What is an intravenous excretory urogram (IVU)?

Use of x-ray contrast medium to produce a series of images which will show any inequality of perfusion of kidneys, rate of renal and bladder filling etc

What is the purpose of a kidney biopsy?

Useful in differential diagnosis of nephritis and in assessing transplant rejection