Anatomy of the Nephron and Urinalysis Quiz

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Questions and Answers

What is the active form of vitamin D?

Calcitriol (correct)

Vitamin A

Vitamin K

Vitamin C

What is the primary hormone responsible for increasing erythrocyte production?

Erythropoietin (EPO) (correct)

Insulin

Aldosterone

Cortisol

What happens if there is inadequate vitamin D in the body?

Development of osteoporosis (correct)

Increased muscle growth

Improved vision

Enhanced memory function

Which of the following is NOT a hormone involved in regulating blood pressure by the kidneys?

Insulin Signup and view all the answers

What is the function of EPO produced in the kidneys?

Increase erythrocyte production Signup and view all the answers

What is the function of the glomerulus in the nephron?

Filtration of blood to form filtrate Signup and view all the answers

What does the presence of leukocytes in urine indicate?

Urinary tract infection Signup and view all the answers

Which factor does NOT affect the color of urine?

High protein diet Signup and view all the answers

What is polyuria?

Overproduction of urine Signup and view all the answers

What is the specific gravity of pure water?

$1.0$ Signup and view all the answers

How do ketones in urine indicate a health condition?

Fat metabolism for energy or low carb intake Signup and view all the answers

What is the main mechanism through which many solutes are transported with sodium?

Symport Signup and view all the answers

Which structure recovers much of the water and some sodium that is still in the nephron?

Loop of Henle Signup and view all the answers

What does Urea do as water leaves at the bottom of the Loop of Henle?

Rids the body of nitrogen Signup and view all the answers

Which hormone increases the number of sodium pumps in the Distal Convoluted Tubule (DCT)?

Aldosterone Signup and view all the answers

What plays a large role in adjusting how much water is reabsorbed in the collecting ducts?

Vasopressin Signup and view all the answers

Which hormone works to inhibit aldosterone and allows for excretion of water?

Natriuretic hormones Signup and view all the answers

What causes vasoconstriction and reduces the amount of blood flowing to the glomerulus?

Renin Signup and view all the answers

Which system is important for kidney function and involves the release of aldosterone due to increased angiotensin 2 levels?

Renin-angiotensin-aldosterone system Signup and view all the answers

What triggers the release of vasopressin to reabsorb water?

Low blood pressure Signup and view all the answers

What is one of the effects of caffeine on the nephron?

Promotes vasodilation Signup and view all the answers

What is the medical term for urination?

Micturition Signup and view all the answers

Which structure prevents large objects like cells and proteins from passing into the nephrons?

Filtration slits Signup and view all the answers

What is released in response to flow rate or sodium disturbances?

Adenosine triphosphate (ATP) and adenosine Signup and view all the answers

Which structure regulates renin release to influence blood volume?

Macula densa Signup and view all the answers

What does ADH cause in the collecting ducts?

Insertion of aquaporin channel proteins into the cell membrane Signup and view all the answers

What is the function of aquaporin channel proteins in the collecting ducts?

Pull water back into the interstitial spaces for reabsorption Signup and view all the answers

What happens if too many proteins get into the urine?

More water will be needed in the urine Signup and view all the answers

What does systemic edema indicate?

Excessive water retention in tissues Signup and view all the answers

Study Notes

Urinary System Structure

The female urethra is approximately 4cm long, making it more prone to infections and UTIs.
The male urethra is approximately 20cm long and passes through the prostate gland.
The bladder collects urine from both ureters and can hold around 600mL of urine.
The ureters are approximately 30cm long and transport urine from the kidneys to the bladder.

Urination and Micturition

Micturition is the medical term for urination.
The urge to urinate is first felt when the bladder contains around 150mL of fluid.
Urine is formed in the kidneys and propelled into the bladder through the ureters.

Kidney Function

The kidneys are approximately the size of a fist and receive around 25% of cardiac output while at rest.
Blood flow to the kidneys comes from the descending aorta and exits to the inferior vena cava.
The right kidney sits slightly lower than the left kidney due to the liver's placement.
Nephrons in the kidney make urine, which flows through ducts and empties into the ureters.
Capillaries recover most of the solutes and water from the nephron and return them to circulation.

Nephron Function

Nephrons work through filtration, reabsorption, and secretion.
Filtrate goes from the capillary to Bowman's capsule easily due to filtration slits and fenestrated capillaries.
Fenestrations prevent large objects like cells and proteins from passing into the nephrons.
Positively charged filtrate passes through more easily.
The basement membrane prevents medium-sized objects from passing through.
The macula densa regulates renin release to influence blood volume.
Nephrons also have many microvilli to absorb and secrete solutes.
They have many mitochondria to produce enough ATP.

Urine Formation and Regulation

The glomerular filtration rate is the amount of filtrate produced per minute.
Fluid is absorbed into Bowman's capsule due to hydrostatic and osmotic pressure.
Osmotic pressure in the blood is important to prevent excessive water loss or retention.
ADH regulates water reabsorption in the collecting ducts.
Without ADH, aquaporin channels are not inserted into the membrane.
Most cells have aquaporin molecules for water transport.
The kidneys regulate blood pressure, osmolarity, and electrolyte balance.
They also regulate pH levels and recover electrolytes like sodium, potassium, and calcium.

Urine Characteristics

Urine is affected by water intake, exercise, environmental temperature, nutrient intake, and other factors.
Urinalysis is done to determine urine content.
Color is affected by some foods, bile obstruction, dehydration, or bleeding.
Specific gravity is the amount of solutes in the urine.
Leukocytes in the urine indicate a urinary tract infection.
Ketones in the urine mean that the body is using fat for energy in preference of glucose or that the diet is low in carbs and proteins.
Nitrates are normally found in the urine.
We must produce at least 500mL of urine each day to get rid of wastes.
Anuria is the absence of urine production, polyuria is the overproduction of urine, and oliguria is the term for renal disease causing little urine production.

Hormonal Regulation

The renin-angiotensin-aldosterone system is important for kidney function.
Aldosterone is released due to angiotensin 2 or increased potassium levels.
Progesterone binds to receptors like aldosterone, but it is much weaker.
Anti-diuretic hormone (ADH) is also called vasopressin and it works to reabsorb water.
Endothelins are powerful vasoconstrictors found in the kidneys.
Natriuretic hormones work to inhibit aldosterone and let sodium leave, resulting in water excretion.
Parathyroid hormone influences calcitriol and will result in higher calcium levels in the blood.

Blood Pressure Regulation

Blood pressure reflects blood volume and is measured in the aorta and carotid sinuses.
Baroreceptors send signals to the central nervous system for a sympathetic or parasympathetic response.
Diuretics increase urine volume.
Caffeine promotes vasodilation in the nephron and inhibits ADH.
Glucose in the urine will increase water in the urine, as in the case of a person with uncontrolled diabetes.

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Description

Test your knowledge on the structure and function of the glomerulus, urine production, factors affecting urine composition, urinalysis, and common urine abnormalities. Learn about the impact of water intake, exercise, diet, and medical conditions on urine characteristics.