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Questions and Answers
What are the two primary "blood-filter" organs in the body?
What are the two primary "blood-filter" organs in the body?
The liver and the kidney
What is the primary function of the kidneys?
What is the primary function of the kidneys?
Filtering blood
How many liters of fluid does the renal system filter from the blood each day?
How many liters of fluid does the renal system filter from the blood each day?
200
What is the name of the functional unit of the kidney?
What is the name of the functional unit of the kidney?
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The kidney contains 5-10 pyramids in the medulla?
The kidney contains 5-10 pyramids in the medulla?
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The cortex of the kidneys is located in the inner region of the kidney?
The cortex of the kidneys is located in the inner region of the kidney?
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What are the two types of nephron?
What are the two types of nephron?
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The loop of Henle is found in the cortical nephron?
The loop of Henle is found in the cortical nephron?
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What is the name of the specialized epithelial cells that line the glomerulus?
What is the name of the specialized epithelial cells that line the glomerulus?
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Which of the following processes are involved in the nephron's functionality? (Select all that apply)
Which of the following processes are involved in the nephron's functionality? (Select all that apply)
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What is the name of the structure that surrounds the glomerulus and facilitates the filtration process?
What is the name of the structure that surrounds the glomerulus and facilitates the filtration process?
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Name the three layers that make up the filtration membrane.
Name the three layers that make up the filtration membrane.
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What is the process called that involves the capillary networks that supply blood to the medulla and are highly permeable to solute and water?
What is the process called that involves the capillary networks that supply blood to the medulla and are highly permeable to solute and water?
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What is the name of the force that favors filtration due to the pressure exerted by the blood within the glomerular capillaries?
What is the name of the force that favors filtration due to the pressure exerted by the blood within the glomerular capillaries?
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What is the name of the force that opposes filtration due to the pressure exerted by the fluid within Bowman's space?
What is the name of the force that opposes filtration due to the pressure exerted by the fluid within Bowman's space?
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What is the name of the force that opposes filtration due to the concentration of proteins in the plasma?
What is the name of the force that opposes filtration due to the concentration of proteins in the plasma?
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What is the normal range for GFR in healthy individuals?
What is the normal range for GFR in healthy individuals?
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What is the name of the intrinsic mechanism of GFR regulation that involves smooth muscle cells responding to changes in pressure?
What is the name of the intrinsic mechanism of GFR regulation that involves smooth muscle cells responding to changes in pressure?
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What is the name of the intrinsic mechanism of GFR regulation that involves specialized cells in the juxtaglomerular apparatus?
What is the name of the intrinsic mechanism of GFR regulation that involves specialized cells in the juxtaglomerular apparatus?
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The sympathetic nervous system can increase GFR by causing vasoconstriction of renal blood vessels?
The sympathetic nervous system can increase GFR by causing vasoconstriction of renal blood vessels?
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Name the hormone that is released by the juxtaglomerular cells in response to decreased blood pressure and promotes vasoconstriction, increasing blood pressure?
Name the hormone that is released by the juxtaglomerular cells in response to decreased blood pressure and promotes vasoconstriction, increasing blood pressure?
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What is the name of the hormone that can lower blood pressure and can increase GFR?
What is the name of the hormone that can lower blood pressure and can increase GFR?
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What is the most common test used to measure GFR?
What is the most common test used to measure GFR?
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Creatinine is secreted by the kidneys?
Creatinine is secreted by the kidneys?
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Low GFR is a sign of kidney disease?
Low GFR is a sign of kidney disease?
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A high GFR is often associated with renal dysfunction?
A high GFR is often associated with renal dysfunction?
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What is the name of the condition that causes the glomerular basement membrane to become thin and porous, resulting in filtration of RBCs and proteins into the urine?
What is the name of the condition that causes the glomerular basement membrane to become thin and porous, resulting in filtration of RBCs and proteins into the urine?
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What is the name of the excitable renal pericytes that regulate filtration by modulating capillaries?
What is the name of the excitable renal pericytes that regulate filtration by modulating capillaries?
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Study Notes
Renal Physiology Overview
- The kidney's primary role is filtering blood.
- The body has two primary blood-filtering organs: the liver and the kidney.
- Both organs remove waste products from the blood, but use different methods.
- The liver identifies unwanted items and disposes of them.
- The kidney disposes of waste and retrieves essential substances.
- Kidneys filter 200 liters of fluid daily from renal blood flow.
- Toxins, metabolic waste products, and excess ions are excreted while retaining essential substances.
- The renal system is responsible for transporting, storing, and eliminating urine.
Renal System Lectures
- Lecture 1: Basic functions of the kidney, overview of nephron function, and glomerular filtration.
- Lecture 2: Urine production.
- Lecture 3: Regulation of ion and water balance.
Renal System Learning Outcomes
- Describe the structure and functions of the renal system.
- Describe the filtration process across the glomerulus.
- Understand glomerular filtration rate.
- Describe the mechanisms that regulate GFR (intrinsic and extrinsic).
The Kidney
- The kidney's role is filtering the blood.
- Kidneys, along with the liver, are the body's primary blood filter organs.
Anatomy of the Kidney
- The medulla contains 5-10 pyramids, whose tips project into the renal pelvis.
- Each kidney is supplied by a renal artery branching from the aorta.
- Branches form interlobar artery.
- Each afferent arteriole supplies one nephron, a functional unit of the kidney.
- The afferent arteriole leads to a ball of capillaries called the glomerulus.
- There are approximately 1,000,000 nephrons in each kidney.
- Two types of nephrons exist: Cortical and juxtamedullary.
Nephron Overview
- The nephron is the structural and functional unit.
- It performs filtration, reabsorption, secretion, and excretion, creating urine.
- Filtration, reabsorption, secretion, and excretion are the four main transport functions.
- Filtrate is isotonic to plasma=300mOsM
- Reabsorption: Proximal convoluted tubule reabsorbs 100% glucose/amino acids, 90% bicarbonate (blood pH), 65% sodium, and 65% water.
- Loop of Henle concentrates the filtrate; permeable to water, impermeable to sodium.
- Distal convoluted tubule is responsive to hormones (aldosterone), and regulates sodium/water reabsorption and blood volume/pressure, as well as blood pH.
- Osmoreceptors in the hypothalamus/arteries detect osmotic changes.
- Dehydration triggers the release of ADH increasing water reabsorption.
- Overhydration results in decreased ADH and decreased water reabsorption, leading to dilute urine.
Nephron: Ultrafiltration
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Approximately 1 litre of blood per minute is filtered through the kidneys.
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Glomerular capillaries increase the surface area and create a 'sieve-like' structure.
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Small molecules (water, glucose, amino acids, ions) are filtered and form filtrate, which is similar to serum.
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The filtrate eliminates blood cells, and proteins.
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Urine is mainly composed of water, salts, and urea.
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The glomerular filtration rate (GFR) is the volume of plasma filtered and is a key indicator of kidney function.
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GFR is determined by glomerular filtration pressure, permeability of the filtration membrane, and surface area.
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Starling forces, including hydrostatic and osmotic forces, affect filtration.
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Normal GFR is 90-125 mL/minute.
Filtration membrane cells
- The filtration membrane's 3 layers (endothelial cells, basement membrane, and podocytes) regulate filtration.
- Endothelial cells have fenestrae for greater permeability.
- The basement membrane is negatively charged, preventing the passage of proteins.
- Podocytes' foot processes create filtration slits, further restricting certain molecules.
Renal Corpuscle: Filtration
- Filtration begins with filtration at the filtration membrane.
- Glomerular Filtration Rate (GFR) is impacted by net pressure, the membrane's permeability, and membrane surface area, with normal levels being 180 liters per day (approximately 125ml/min)
Regulation of GFR
- GFR is usually maintained within a normal range despite blood pressure fluctuations.
- Crucial for maintaining stable kidney function and elimination of waste.
- Intrinsic regulation involves myogenic response and tubuloglomerular feedback.
- Myogenic response: Arteriole walls adjust to maintain blood flow in response to altered blood pressure.
- Tubuloglomerular feedback: Detects changes in solute concentration in the filtrate; adjusted blood flow to manage filtrate composition.
- Extrinsic regulation involves hormonal and neural influence.
- Hormonal regulation: ANP and angiotensin II influence GFR.
- Neural Regulation: Sympathetic nerves influence GFR through vasoconstriction.
- Blood pressure fluctuations affect GFR via constriction or dilation of afferent and efferent arterioles.
- Creatinine clearance is a method for measuring GFR.
Measurement of GFR: Creatinine Clearance
- Urine collected over 24 hours and blood samples are taken to determine how much creatinine is filtered by the kidneys.
- Creatinine is a waste product from creatine metabolism, not reabsorbed or secreted, filtering directly through the kidneys.
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Description
Explore the essential functions of the renal system, including blood filtration and urine production. This quiz covers key concepts from the anatomy and physiology of the kidneys and their role in maintaining the body's balance. Test your understanding of nephron function, glomerular filtration, and urine management.
