Ch. 2 - Renal Function Flashcards by Zean Earl Carpeso

Functional units of the kidney

Nephron

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Enumerate the 2 types of nephrons

Cortical

Juxtamedullary

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Makes up 85% of the nephrons, primarily situated in the cortex of the kidney and responsible for removal of waste products and reabsorption of nutrients

Cortical nephrons

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Type of nephron that has a longer loop of Henle that extends deep into to the medulla of the kidney. Primary function is concentration of the urine

Juxtamedullary nephron

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What renal functions control the ability of the kidney to clear waste products selectively from the blood and simultaneously maintain the body’s essentail water and electrolyte balances?

Renal blood flow
Glomerular filtration
Tubular reabsorption
Tubular secretion

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What supplies blood to the kidney?

Renal artery

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Blood enters the capillaries of the nephron through the _____.

Afferent arteriole

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Blood flows through the glomerulus and into the _____.

Efferent arteriole

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The (smaller/larger) size of the efferent arteriole increases the glomerular capillary pressure.

Smaller

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Before returning to the renal vein, blood from the efferent arteriole enters the _____ and the _____ and flows slowly through the cortex and medulla of the kidney close to the tubules.

Peritubular capillaries

Vasa Recta

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The immediate reabsorption of essential substances ocuurs in the _____.

Proximal convoluted tubule

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Final adjustment of urine concentration occurs in the _____

Distal convoluted tubule

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The major exchange of water and salt between the blood and medullary interstitium take place in what area?

Loop of Henle

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This exchange maintains the osmotic gradient (salt concentration) in the medulla.

Exchange of water and salt between the blood and medullary interstitium.

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Based on the average size of 1.73 m^2, the total renal blood flow is approximately _____, and the total renal plasma flow ranges _____.

1,200 mL/min, 600 - 700 mL/min

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The glomerulus consists of a coil of approximately eight capillary lobes referred to as the _____

Capillary tufts

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It is located within the Bowman’s capsule; it seves as a non-selective filter of plasma substances with molecular weights of less than 70,000.

Glomerulus

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Forms the beginning of the renal tubule

Bowman’s capsule

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Enumerate the factors that influence the actual filtration rate in the kidney

Cellular structure of the capillary walls and Bowman’s capsule
Hydrostatic and Oncotic pressure
Feedback mechanisms of the Renin-angiotensin-aldosterone system

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The plasma filtrate must pass through three cellular layers in the glomerulus which are:

Capillary wall membrane
Basement membrane
Visceral epithelium of Bowman’s capsule

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The _____ cells of the capillary wall contains pores and are referred to as fenestrated.

Endothelial

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The pores in the endothelial cells increase capillary permeability but do not allow the passage of _____ and _____ cells

Large molecules and Blood cells.

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By increasing or decreasing the size of the (Afferent/Efferent) arteriole, an autoregulatory mechanism within the juxtaglomerulal apparatus maintains the glomerular blood pressure at a relatively constant rate regardless of fluctuations in systemic blood pressure.

Afferent

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RAAS stands for

Rein-Angiotensin-Aldosterone-System

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Controls the regulation of the flow of blood to and within the glomerulus. Responds to changes in blood pressure and plasma sodium content.

RAAS

Monitors the changes in blood pressure and plasma sodium content.

Juxtaglomerular apparatus

Consists of Juxtaglomerular cells in the afferent arteriole and the macula densa of the distal convoluted tubule

Juxtaglomerular apparatus

Low _____ content decreases water retention within the circulatory system, resulting in a decreased overall blood volume and subsequent decrease in blood pressure.

Plasma sodium

An enzyme produced by the juxtaglomerular cells. Secreted when the macula densa senses changes such as the decrease in low plasma sodium content, overall blood volume, and blood pressure.

Renin

Reacts with the blood-borne substrate angiotensinogen to produce the inert hormone angiotensin 1.

Renin

Formed when renin reacts with angiotensinogen

Angiotensin 1

As angiotensin 1 passes through the lungs, what enzyme changes it to the active form angiotensin 2

Angiotensin Converting Enzyme (ACE)

Formed when ACE changes angiotensin 1 into its active form

Angiotensin 2

What are the ways angiotensin 2 corrects renal blood flow?

Vasodilation of the Afferent arterioles Constriction of the Efferent arterioles Stimulating reabsorption of sodium in the proximal convoluted tubules Triggering the release of the sodium-retaining hormone: Aldosterone by the adrenal cortex and Antidiuretic hormone by the hypothalamus

Angiotensin 2 corrects renal blood flow by causing: | (Vasodilation/Constriction) of the Afferent arterioles;

Vasodilation

Angiotensin 2 corrects renal blood flow by causing: | (Vasodilation/Constriction) of the Efferent arterioles;

Constriction

Angiotensin 2 corrects renal blood flow by: | Stimulating reabsorption of sodium in the (proximal/distal) convoluted tubules

Proximal

Angiotensin 2 corrects renal blood flow by: Triggering the release of the sodium-retaining hormone _____ by the adrenal cortex, causing reabsorption of sodium and excretion of potassium in the distal convoluted tubule and collecting duct

Aldosterone

Angiotensin 2 corrects renal blood flow by: | Triggering the release of _____ by the hypothalamus to stimulate water reabsorption in the collecting duct

Antidiuretic hormone (ADH)

As systematic blood pressure and plasma sodium content increase, the secretion of renin (increases/decreases)?

Decreases

The fluid that leaves the glomerulus has a specific gravity of _____ and confirms that it is an ultrafiltrate of plasma

1.010

When the plasma ultrafiltrate enters the proximal convoluted tubule, the _____, through cellular transport mechanisms, begin reabsorbing the essential substances and water

Nephrons

Enumerate substances that undergo Active transport

Glucose, Amino acids, Salts, Chloride, Sodium

Enumerate substances that undergo Passive transport

Water, Urea, Sodium

The active transport of glucose, amino acids, and salts occur at what location?

Proximal convoluted tubule

The active transport of chloride occurs at what location?

Ascending loop of Henle

The active transport of sodium occurs at what location?

Proximal and Distal convoluted tubules

The passive transport of water occurs at what location?

Proximal convoluted tubule Descending loop of Henle Collecting duct

The passive transport of Urea occurs at what location?

Proximal convoluted tubule | Ascending loop of Henle

The passive transport of sodium occurs at what location?

Ascending loop of Henle

What substances transports passively through the PCT?

Water and Urea

What substances transports passively through the Acending loop of Henle?

Sodium and Urea

What substances transports actively through the PCT?

Glucose, Amino acids, Salts and Sodium

What substance can undergo both active and passive transport?

Sodium

What are the cellular mechanisms involved in tubular reabsorption?

Active and Passive transport

For this type of transport mechanism to occur, the substance to be reabsorbed must combine with a carrier protein contained in the membranes of the renal tubular cells.

Active transport

The type of transport wherein the movement of molecules across a membrane is the result of differences in their concentration or electrical potential on opposite sides of the membranes (gradient).

Passive transport

Passive reabsorption of water takes place in all parts of the nephrons except the _____, the walls of which are impermeable to water.

Ascending loop of Henle

It is referred to as the differences of molecules in terms of their concentration or electrical potential on opposite sides of the membrane.

Gradient

Passive reabsorption of _____ accompanies the active transport of chloride in the ascending loop.

Sodium

What happens when the plasma concentration of a substance that is normally completely reabsorbed reaches an abnormally high level?

The filtrate concentration exceeds the maximal reabsorptive capacity (Tm) of the tubules The substance begins appearing in urine

The plasma concentration at which active transports stops is termed _____.

Renal thresholl

What is the renal threshold for glucose?

160 - 180 mg/dL

Renal concentrations begin in the _____ and _____, where the filtrate is exposed to the high osmotic gradient of the renal medulla.

Descending loop of Henle, | Ascending loop of Henle

_____ is removed by osmosis in the descending loop of Henle, and _____ and _____ are reabsorbed in the ascending loop.

Water; | Sodium, chloride

Excessive reabsorption is prevented by the water-impermeable walls of the ascending loop. This selective reabsorption process is called the _____ and serves to maintain the osmotic gradient of the medulla.

Concurrent mechanism

After getting reabsorbed in the ascending loop of Henle, sodium is continually reabsorbed in the _____, under the control of the hormone _____, which regulates reabsorption in response to the body's need for sodium.

Distal convoluted tubule; | Aldosterone

The final concentration of the filtrate through the reabsorption of water begins at the _____ and continues in the _____.

Distal convoluted tubule; | Collecting ducts

The hormone that renders the walls of the distal convoluted tubule and collecting duct permeable or impermeable to water.

Vasopressin | Antidiuretic hormone

A (high/low) level of ADH increases permeability resulting in increased reabsorption of water, and a (high/low)-volume concentrated urine.

High; | Low

A (high/low) level of ADH renders the walls impermeable to water, resulting in a (high/low)-volume dilute urine.

Low; | High

Production of aldosterone is controlled by the body's _____ concentration, while production of ADH is determined by the state of body hydration.

Sodium

Increased Body hydration (Fluid volume) (Increased/Decreased) ADH (Increased/Decreased) Urine volume

Decreased; | Increased

Decreased Body hydration (Fluid volume) (Increased/Decreased) ADH (Increased/Decreased) Urine volume

Increased; | Decreased

It is a condition wherein there is increased urine volume

Polyuria

It is a condition wherein there is decreased urine volume

Oliguria

It is a condition wherein there is no urine output

Anuria

This process involves the passage of substances from the blood in the peritubular capillaries to the tubular filtrate.

Tubular secretion

What are the two major functions of the tubular secretion?

Elimination of waste products not filtered by the glomerulus | Regulation of the acid-base balance in the body through the secretion of hydrogen atoms

The major site for removal of these nonfiltered substances (substances bound to protein carriers) is the _____.

Proximal convoluted tubule

What is the normal blood pH?

7.4

The buffering capacity of the blood depends on what type of ions? These are readily filtered by the glomerulus and must be expediently returned to the blood to maintain the proper pH.

Bicarbonate (HCO3-) ions

The secretion of _____ ions by the renal tubular cells into the filtrate prevents the filtered bicarbonate from being excreted in the urine, and causes a return of a bicarbonate ion to the plasma.

Hydrogen (H+) ions

Reabsorption of the filtered bicarbonate occurs primarily in the _____.

Proximal convoluted tubule

To what can the hydrogen (H+) ion bind to/react with so that it will be excreted in the urine?

Phosphate ion, | Ammonia

It is the inabilty to produce an acid urine. Caused by a disruption in the secretion of hydrogen ions or reabsorption of bicarbonate ions

Metabolic acidosis | Renal tubular acidosis