Questions and Answers
Which of the following are functions of the urinary system? (Select all that apply)
What are the retroperitoneal organs?
Kidneys, Pancreas
What is the outer portion of the kidney called?
Cortex
What is the inner portion of the kidney?
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What are renal pyramids?
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What separates the renal pyramids?
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What structure is found at the end of each renal pyramid?
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What is a minor calyx?
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What does a major calyx do?
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Describe the renal pelvis.
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What is the function of the ureter?
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Approximately how many nephrons does each kidney contain?
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What is the path of urine drainage?
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What type of epithelial tissue is present from the minor calyx down?
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What is the path of blood supply to the kidneys?
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What is a glomerulus?
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What is the function of vasa recta?
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What is a nephron?
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What is the pathway through the nephron?
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What is a cortical nephron?
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What is a juxtamedullary nephron?
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What are the histological features of the renal tubule and collecting duct?
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What are the three basic functions of the nephron?
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What is glomerular filtration?
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What is tubular reabsorption?
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What is tubular secretion?
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What is a renal corpuscle?
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What are mesangial cells?
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What are podocytes?
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What is the function of macula densa?
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What are juxtaglomerular cells?
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What are extraglomerular cells?
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What are the four basic renal processes?
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What occurs during filtration?
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What is reabsorption?
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What is secretion?
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What is excretion?
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What substances are reabsorbed by the proximal tubule?
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What substances are secreted by the proximal tubule?
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What substances are secreted by the distal tubule?
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What is aldosterone?
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What does Anti-Diuretic Hormone (Vasopressin) do?
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What is the function of the internal urethral sphincter?
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What is the function of the external urethral sphincter?
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Study Notes
Functions of the Urinary System
- Regulates plasma ion concentrations, blood volume and pressure, and plasma pH.
- Conserves nutrients by limiting excretion.
- Eliminates organic wastes and synthesizes hormones.
Anatomy of the Urinary System
- The kidneys and pancreas are classified as retroperitoneal organs.
- The renal cortex is the outer portion of the kidney, typically lighter in color.
- The renal medulla is the inner portion of the kidney, consisting of renal pyramids.
Renal Structures
- Renal pyramids are triangular areas of tissue within the medulla.
- Renal columns are extensions of the cortex that separate the renal pyramids.
- Renal papillae are funnel-like structures at the ends of renal pyramids, leading to urine drainage.
Urine Drainage System
- Minor calyx collects urine from renal papillae and directs it to major calyces.
- Major calyx is formed by the convergence of several minor calyces and drains urine into the renal pelvis.
- Renal pelvis is where major calyces converge and leads to the ureter.
Nephron Structure and Function
- Each kidney contains approximately 1 million nephrons, the functional units of the kidneys.
- Nephrons consist of several segments including Bowman's capsule, proximal tubule, loops of Henle, distal tubule, and collecting duct.
- The flow of urine follows the pathway: collecting duct → papillary duct → minor calyx → major calyx → renal pelvis → ureter → urinary bladder.
Types of Nephrons
- Cortical nephrons primarily located in the renal cortex, making up 85% of nephrons with shorter loops of Henle.
- Juxtamedullary nephrons are situated near the medulla, contain vasa recta, and account for 15% of nephrons.
Epithelial Tissue in Nephrons
- Most renal tubular regions are lined with simple cuboidal epithelium, except for the nephron loop and certain limbs which have simple squamous epithelium.
Nephron Processes
- The three fundamental functions of nephrons include filtration, reabsorption, and secretion.
- Filtration occurs at the glomerulus, allowing blood plasma and substances to enter Bowman's capsule.
- Tubular reabsorption retrieves water, ions, and substances from the nephron back into the bloodstream.
- Tubular secretion moves wastes, drugs, and excess ions from peritubular capillaries into the nephron.
Renal Corpuscle and Associated Cells
- The renal corpuscle consists of Bowman's capsule and the glomerulus, where filtration occurs.
- Mesangial cells regulate glomerular filtration rate by contracting and adjusting blood flow through capillaries.
- Podocytes form filtration slits to filter smaller molecules during glomerular filtration.
- Macula densa cells monitor electrolyte concentration and regulate glomerular filtration by influencing arteriole constriction.
Hormonal Regulation
- Juxtaglomerular cells in the afferent arteriole secrete renin to help regulate blood pressure.
- Aldosterone from the adrenal cortex increases sodium reabsorption and potassium secretion in the distal tubule.
- Anti-diuretic hormone (ADH) increases water reabsorption in the distal tubule, helping maintain fluid balance.
Urinary Sphincters
- Internal urethral sphincter controls involuntary opening and closing of the urethra.
- External urethral sphincter consists of skeletal muscle allowing voluntary control over urination.
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Description
This quiz covers the essential functions of the urinary system, as outlined in Chapter 25. Participants will learn about the regulatory roles of the kidneys, as well as their anatomical significance. Get ready to test your knowledge on the key concepts associated with urinary function.