Urinary System Functions Quiz

Questions and Answers

How does the urinary system contribute to homeostasis?

Altering blood composition, pH, volume, and pressure; maintaining blood osmolarity; excreting wastes and foreign substances; and producing hormones.

What part of the body is responsible for the major work of the urinary system?

The kidneys.

What are the 6 functions of the kidneys?

Regulation of blood ionic composition, * Regulation of blood pH, * Regulation of blood volume, * Regulation of blood pressure, * Maintenance of blood osmolarity, * Production of hormones, * Regulation of blood glucose level, * Excretion of wastes and foreign substances.

What does regulation of blood ionic composition consist of?

The kidneys help regulate the blood levels of several ions, most importantly sodium ions (Na+), potassium ions (K+), calcium ions (Ca2+), chloride ions (Cl−), and phosphate ions (HPO42−). Signup and view all the answers

What does regulation of blood pH consist of?

The kidneys excrete hydrogen ions (H+) into the urine and conserve bicarbonate ions (HCO3−). Signup and view all the answers

What does regulation of blood volume consist of?

Conserving or eliminating water in the urine. Signup and view all the answers

What does regulation of blood pressure consist of?

Secreting the enzyme renin, activating the renin-angiotensin-aldosterone pathway. Signup and view all the answers

What does maintenance of blood osmolarity consist of?

By separately regulating loss of water and solutes in the urine. Signup and view all the answers

What does production of hormones consist of?

The kidneys produce calcitriol and erythropoietin. Signup and view all the answers

What does regulation of blood glucose level consist of?

The kidneys can use glutamine in gluconeogenesis and release glucose into the blood. Signup and view all the answers

What does excretion of wastes and foreign substances consist of?

Excreting wastes from metabolic reactions and foreign substances from the diet. Signup and view all the answers

Describe the kidneys.

Bean-shaped organs located just above the waist between the peritoneum and the posterior wall of the abdomen. Signup and view all the answers

Why are kidneys said to be retroperitoneal?

Because they are posterior to the peritoneum. Signup and view all the answers

Where exactly are the kidneys located?

Between the levels of the last thoracic and third lumbar vertebrae. Signup and view all the answers

Which kidney is lower?

The right kidney is slightly lower than the left. Signup and view all the answers

What are the functions of the urinary system?

<ol> <li>Regulate blood volume and composition; 2. Ureters transport urine; 3. Urinary bladder stores urine; 4. Urethra discharges urine.</li> </ol> Signup and view all the answers

Which organs constitute the urinary system?

The kidneys, ureters, urinary bladder, and urethra. Signup and view all the answers

How long is a typical adult kidney?

10-12 cm (4-5 in.) long, 5-7 cm (2-3 in.) wide, and 3 cm (1 in.) thick. Signup and view all the answers

What is the indentation near the center of the concave border called?

Renal hilum. Signup and view all the answers

What are the three tissue layers of the kidneys?

Renal capsule, adipose capsule, renal fascia. Signup and view all the answers

Describe the renal capsule.

A smooth, transparent sheet of dense irregular connective tissue. Signup and view all the answers

Describe the adipose capsule.

A mass of fatty tissue surrounding the renal capsule. Signup and view all the answers

Describe the renal fascia.

A thin layer of dense irregular connective tissue that anchors the kidney. Signup and view all the answers

What is nephroptosis?

An inferior displacement or dropping of the kidney. Signup and view all the answers

What are the two distinct regions of the internal kidneys?

Renal cortex and renal medulla. Signup and view all the answers

Describe the renal cortex.

A superficial, light red area. Signup and view all the answers

Describe the renal medulla.

A deep, darker reddish-brown inner region. Signup and view all the answers

What is renal blood flow?

The blood flow through both kidneys is about 1200 mL per minute. Signup and view all the answers

What is parenchyma?

The functional portion of the kidney. Signup and view all the answers

What are nephrons?

The filtering unit of the kidney. Signup and view all the answers

How does blood flow into the kidneys?

By the renal arteries at the hilus. Signup and view all the answers

What is the hollow tube called that urine passes into after each kidney?

Ureter. Signup and view all the answers

The 2 ureters conduct urine from the kidneys to what?

Urinary bladder. Signup and view all the answers

What is the function of the portal system?

To filter fluid out of the blood into the nephron and then to reabsorb the fluid back into the blood. Signup and view all the answers

What are the forces governing fluid movement in the renal portal system similar to?

Those that determine filtration of water and molecules out of systemic capillaries. Signup and view all the answers

Fluid from the ascending limb of the loop of Henle passes into what?

Distal tubule. Signup and view all the answers

The distal tubule of up to 8 nephrons drains into a single larger tube called what?

Collecting duct. Signup and view all the answers

Collecting ducts pass from the cortex through the medulla and drain fluid into what?

Renal pelvis. Signup and view all the answers

What is the region called where the nephron twists and folds back on itself?

Juxtaglomerular apparatus. Signup and view all the answers

What are the 3 basic renal functions?

Glomerular filtration, tubular reabsorption, tubular secretion. Signup and view all the answers

What is glomerular filtration?

The movement of fluid from blood into the lumen of the nephron. Signup and view all the answers

What is tubular reabsorption?

Moving substances from the filtrate back into the blood. Signup and view all the answers

What is tubular secretion?

Selectively removing molecules from the blood and adding them to the filtrate. Signup and view all the answers

How much plasma that passes through the glomeruli is filtered into the renal tubules daily?

20%. Signup and view all the answers

What is the result of a decrease in ECF osmolarity?

Inhibits ADH secretion from the posterior pituitary gland. Signup and view all the answers

What stimulates ADH secretion from the posterior pituitary gland?

An increase in ECF osmolarity. Signup and view all the answers

What monitors the ECF solute (Na+) concentration?

Chemoreceptors in the hypothalamus. Signup and view all the answers

Regarding the Atrial Natriuretic Hormone, which atrium is excessively stretched by elevated blood pressure?

Right atrium. Signup and view all the answers

Study Notes

Urinary System Overview

Contributes to homeostasis by regulating blood composition, pH, volume, and pressure, maintaining blood osmolarity, excreting waste, and producing hormones.
Major organ responsible for urinary system functions: the kidneys.

Functions of the Kidneys

Regulate blood ionic composition: sodium, potassium, calcium, chloride, and phosphate ions.
Regulate blood pH by excreting hydrogen ions and conserving bicarbonate ions.
Control blood volume: an increase leads to higher blood pressure while a decrease lowers it.
Regulate blood pressure through secretion of the enzyme renin, activating the renin-angiotensin-aldosterone pathway.
Maintain blood osmolarity, targeting a constant level around 300 mOsm/liter.
Produce hormones: calcitriol (active vitamin D) and erythropoietin (stimulates red blood cell production).
Regulate blood glucose levels via gluconeogenesis from glutamine.
Excrete waste products and foreign substances through urine.

Kidney Structure

Kidneys are bean-shaped, located between the last thoracic and third lumbar vertebrae, partly protected by the 11th and 12th ribs.
Right kidney is lower than the left due to the liver's position.
The renal hilum is the indentation on the concave border of the kidney.
Three tissue layers: renal capsule, adipose capsule, and renal fascia, each providing protection and structural support.

Nephron Functionality

Nephrons are the functional units of the kidney, with blood flow approximately 1200 mL per minute.
Each nephron consists of glomerular filtration, tubular reabsorption, and tubular secretion.
The glomerulus filters fluid into the nephron; hydrostatic pressure drives this process.
The distal tubule connects to collecting ducts that drain into the renal pelvis.

Hormonal Regulation

Antidiuretic Hormone (ADH) and aldosterone regulate water, sodium, and potassium levels in urine.
Chemoreceptors in the hypothalamus monitor extracellular fluid (ECF) solute concentration (Na+).
Elevated ECF osmolarity stimulates ADH secretion; decreased osmolarity inhibits it.
Atrial Natriuretic Hormone (ANH) released in response to increased venous return and right atrium wall stretching, aiding in blood volume regulation.

Common Kidney Conditions

Nephroptosis: inferior displacement of the kidney due to inadequate support from surrounding structures and fat.
Imbalances in filtered substances can impact blood pressure, membrane potentials, and cell volume.

Kidney Dimensions

Typical adult kidneys measure 10-12 cm long, 5-7 cm wide, and 3 cm thick, similar in size to a bar of bath soap.

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Description

Test your knowledge on the urinary system and its vital role in maintaining homeostasis. This quiz covers fundamental concepts such as kidney functions, blood regulation, and waste excretion. Challenge yourself to see how well you understand this essential system.