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Questions and Answers
ADH helps to conserve water by increasing urine production when the body is dehydrated.
ADH helps to conserve water by increasing urine production when the body is dehydrated.
False
What is the process where substances are moved out of the tubules and into the blood, such as in the PCT?
What is the process where substances are moved out of the tubules and into the blood, such as in the PCT?
Reabsorption
Which enzyme is secreted by the cells of the juxtaglomerular apparatus in the kidneys?
Which enzyme is secreted by the cells of the juxtaglomerular apparatus in the kidneys?
The female urethra is about __ cm, or __ inches long.
The female urethra is about __ cm, or __ inches long.
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What is the function of the adipose capsule around the kidneys?
What is the function of the adipose capsule around the kidneys?
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What are the structures that help to protect the kidneys from damage and trauma?
What are the structures that help to protect the kidneys from damage and trauma?
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The renal cortex is surrounded by the renal capsule.
The renal cortex is surrounded by the renal capsule.
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Renal Medulla is near the innermost part of the kidney, containing the renal pyramids where urine ________ takes place.
Renal Medulla is near the innermost part of the kidney, containing the renal pyramids where urine ________ takes place.
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What is the primary function of a nephron?
What is the primary function of a nephron?
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What is polyuria?
What is polyuria?
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What is oliguria?
What is oliguria?
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What is a key cardinal symptom of diabetes related to urine output?
What is a key cardinal symptom of diabetes related to urine output?
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What is one of the main symptoms people report when they have a urinary tract infection?
What is one of the main symptoms people report when they have a urinary tract infection?
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What does 'Dysuria' mean?
What does 'Dysuria' mean?
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______ is the presence of red blood cells in urine, usually from infection or injury.
______ is the presence of red blood cells in urine, usually from infection or injury.
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Proteinuria can indicate kidney issues if there is excessive protein in the urine.
Proteinuria can indicate kidney issues if there is excessive protein in the urine.
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What does Glycosuria refer to?
What does Glycosuria refer to?
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What is the primary function of the kidneys in relation to fluid balance?
What is the primary function of the kidneys in relation to fluid balance?
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What percentage of the filtered blood is reabsorbed and put back into circulation through the renal vein?
What percentage of the filtered blood is reabsorbed and put back into circulation through the renal vein?
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Diuretics are commonly used to decrease fluid volume in patients.
Diuretics are commonly used to decrease fluid volume in patients.
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Tubular reabsorption involves the movement of substances from the filtrate across the wall of the nephron back into the ____ of the peritubular capillaries.
Tubular reabsorption involves the movement of substances from the filtrate across the wall of the nephron back into the ____ of the peritubular capillaries.
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Match the following kidney functions with their descriptions:
Match the following kidney functions with their descriptions:
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What does ADH stand for?
What does ADH stand for?
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ADH binding to its receptor triggers signal transduction within the cell.
ADH binding to its receptor triggers signal transduction within the cell.
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Angiotensin 2 acts on the adrenal cortex causing it to secrete ________.
Angiotensin 2 acts on the adrenal cortex causing it to secrete ________.
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What is the primary function of the kidneys?
What is the primary function of the kidneys?
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Match the following parts with their descriptions:
Match the following parts with their descriptions:
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Study Notes
Kidney Anatomy and Function
- The kidneys are two small, bean-shaped organs located at the back of the peritoneum (retroperitoneal) in the superior lumbar region, just below the rib cage on each side of the spine.
- The right kidney is located slightly lower than the left kidney to accommodate the liver.
Kidney Structure
- The kidney has three main layers: the renal capsule, renal cortex, and renal medulla.
- The renal capsule is a tough, fibrous connective tissue layer that covers the outside of each kidney, composed primarily of collagen and elastin.
- The renal cortex is the outermost layer, surrounded by the renal capsule, and houses the nephrons.
- The renal medulla is the innermost layer, containing the renal pyramids where urine formation takes place.
Nephron Structure and Function
- The nephron is the functional unit of the kidney, stretching from the cortex to the medulla.
- Each kidney has approximately 1,000,000 nephrons.
- The nephron has three main parts: the glomerulus, proximal convoluted tubule, and distal convoluted tubule.
- The glomerulus is a tangle of capillaries surrounded by the Bowman's capsule, where blood pressure forces water and solutes out of the capillaries and into the lumen of the Bowman's capsule.
- The proximal convoluted tubule and distal convoluted tubule are responsible for reabsorption and secretion of substances.
Kidney Functions
- The kidneys remove excess fluid and waste products from the body.
- The kidneys maintain acid-base balance by regulating the concentration of hydrogen ions.
- The kidneys regulate blood pressure by controlling the amount of salt and water in the body.
- The kidneys produce hormones, such as erythropoietin and calcitriol, and the enzyme renin.
Blood Flow and Filtration
- Blood flows into the kidney through the renal artery and exits the kidney through the renal vein.
- Urine exits the kidneys via the ureter and drains into the bladder.
- Blood is filtered through the kidneys about 6 times a day.
- The glomerulus filters the waste molecules (urea, salt, glucose, amino acids, and water) from the blood.
Diuretics
- Diuretics are used to stimulate the kidneys to excrete an increased amount of fluid.
- Diuretics work in the nephron to increase urine production.
- There are three types of diuretics: carbonic anhydrase inhibitors (CAIs), loop diuretics, and potassium-sparing diuretics.
- Loop diuretics, such as Lasix or furosemide, are the strongest diuretic medications and are used to treat renal failure.
- Thiazide diuretics cause a drop in potassium, while potassium-sparing diuretics are used to help patients who are losing too much potassium in treatment.### Kidney Physiology: Mechanisms of Urine Formation
- The filtrate obtained from the glomerulus is called the primary urine, which is almost equal to blood in chemical composition, except for the presence of blood cells.
- The primary urine passes into the proximal convoluted tubule (PCT), where useful substances such as glucose, amino acids, and vitamins are reabsorbed.
- Filtration occurs due to non-selective forces of blood pressure, resulting in the movement of water and small molecules out of the glomerular capillaries.
Functions of Nephrons
- Filtration: the movement of water and small molecules out of the glomerular capillaries into the Bowman's capsule.
- Tubular reabsorption: the process of reabsorbing useful substances from the primary urine back into the bloodstream in the PCT.
- Tubular secretion: the active transport of solutes from the bloodstream into the filtrate in the distal convoluted tubule (DCT).
Tubular Secretion
- It promotes sodium reabsorption in the PCT.
- It induces the release of aldosterone from the adrenal cortex, which promotes sodium and water retention in the kidneys.
Renin-Angiotensin-Aldosterone System (RAAS)
- A hormonal system that controls blood pressure.
- Renin is an enzyme secreted by the juxtaglomerular cells in the kidneys, which converts angiotensinogen into angiotensin 1.
- Angiotensin 1 is converted into angiotensin 2 by the angiotensin-converting enzyme (ACE) in the lungs.
- Angiotensin 2 stimulates vasoconstriction and the release of aldosterone, leading to increased blood pressure.
Antidiuretic Hormone (ADH) Mechanism
- A hormone released by the posterior pituitary gland, regulated by the hypothalamus.
- ADH stimulates water reabsorption in the collecting duct, leading to concentrated urine and decreased urine production.
- Increased ADH secretion helps conserve water in the body.
Urinary Tract Infections (UTIs)
- Can occur in any part of the urinary system, including the kidneys, ureters, bladder, and urethra.
- Most often occurs in the bladder or urethra, but can progress to the kidneys if left untreated.
Kidneys and Ureters
- The kidneys filter waste and reabsorb what the body needs.
- The ureters are thin tubes of muscle that carry urine from the kidneys to the bladder.
Bladder and Urethra
- The bladder is a hollow, muscular, balloon-shaped organ that expands as it fills with urine.
- The urethra is the tube that carries urine from the bladder out of the body.
- The female urethra is about 4 cm (1.5 inches) long, while the male urethra is about 20 cm (7-7.9 inches) long.
Brain and Urination
- The brain, especially the maturation center in the pons, plays a crucial role in controlling urination.
- Voluntary control over the external urethral sphincter develops as the central nervous system matures.
- The brain receives sensory signals from the bladder wall and communicates with the cortex to determine the appropriateness of urination.### Urination Process
- When the bladder is full, stretch receptors in the wall of the bladder send nerve impulses to the spinal cord.
- The signal returns to the bladder, stimulating contraction of the detrusor muscle and relaxation of the internal urethral sphincter.
- This is an involuntary reflex, predominant in infants and young children.
- Three simultaneous events must occur for urination to happen:
- Contraction of the detrusor muscle by the ANS
- Opening of the internal urethral sphincter by the ANS
- Opening of the external urethral sphincter by the somatic nervous system
Urine Composition
- Urine is predominantly water (over 95%)
- The remaining 5% consists of:
- Urea
- Chloride
- Sodium
- Potassium
- Creatinine
- Other dissolved ions
- Inorganic and organic compounds (e.g. proteins, hormones, metabolites)
Abnormal Urine Output
- Dysuria: painful or uncomfortable urination, often due to urinary tract infections
- Hematuria: red blood cells in urine, often due to infection or injury
- Proteinuria: protein content in urine, often due to leaky or damaged glomeruli
- Glycosuria: glucose in urine, often due to excess plasma glucose in diabetes
- Oliguria: abnormally small amount of urine, often due to shock or kidney damage
- Polyuria: abnormally large amount of urine, often caused by diabetes
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Description
This quiz assesses knowledge of the renal system, including the excretory process, kidney structure, and related functions. Questions cover topics such as reabsorption, hormone secretion, and kidney protection.
