Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

25. The Urinary System

Renal Physiology Step 1: Glomerular Filtration

Anatomy & Physiology

25. The Urinary System

Renal Physiology Step 1: Glomerular Filtration

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3:22 minutes

Problem 5

Textbook Question

More than one choice may apply.
Which of the following is dependent on tubular secretion?
a. Clearing penicillin from the blood
b. Removal of nitrogenous wastes that have been reabsorbed
c. Removal of excess potassium ions from the blood
d. Control of blood pH

Verified step by step guidance

Understand the concept of tubular secretion: Tubular secretion is the process by which substances are actively transported from the blood in the peritubular capillaries into the renal tubules. This mechanism helps remove waste products, regulate ion concentrations, and maintain acid-base balance.

Analyze option (a): Clearing penicillin from the blood involves tubular secretion because penicillin is actively secreted into the renal tubules for excretion. This process bypasses filtration and relies on active transport mechanisms.

Analyze option (b): Removal of nitrogenous wastes that have been reabsorbed can involve tubular secretion. For example, urea and other nitrogenous wastes may be secreted back into the tubules after being reabsorbed in earlier stages of filtration.

Analyze option (c): Removal of excess potassium ions from the blood is dependent on tubular secretion. Potassium ions are actively secreted into the distal tubules and collecting ducts to regulate electrolyte balance.

Analyze option (d): Control of blood pH is dependent on tubular secretion. Hydrogen ions (H⁺) and bicarbonate ions (HCO₃⁻) are secreted or reabsorbed in the renal tubules to maintain acid-base balance in the blood.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Tubular Secretion

Tubular secretion is a process in the kidneys where substances are actively transported from the blood into the renal tubules. This mechanism is crucial for eliminating waste products, regulating electrolyte balance, and maintaining acid-base homeostasis. It allows the body to excrete substances like drugs and excess ions that are not filtered by the glomerulus.

Renal Clearance

Renal clearance refers to the volume of plasma from which a substance is completely removed by the kidneys per unit time. It is an important measure for understanding how effectively the kidneys are functioning, particularly in the context of drugs like penicillin, which are cleared from the bloodstream through both filtration and secretion processes.

Acid-Base Balance

Acid-base balance is the regulation of the pH levels in the body fluids, primarily managed by the kidneys and lungs. The kidneys contribute by secreting hydrogen ions and reabsorbing bicarbonate, which helps control blood pH. This balance is vital for normal cellular function and overall metabolic processes.

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Related Practice

Textbook Question

More than one choice may apply.

What is the glomerulus?

a. The same as the renal tubule

b. The same as Bowman's capsule

c. The same as the nephron

d. Capillaries

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Textbook Question

Explain the process and purpose of tubular secretion.

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Textbook Question

Explain the important differences between blood plasma and glomerular filtrate, and relate the differences to the structure of the filtration membrane.

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Textbook Question

Filtration at the glomerulus is inversely related to

a. Water reabsorption

b. Capsular hydrostatic pressure

c. Arterial blood pressure

d. Acidity of the urine

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Textbook Question

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

d. Filtrate flows from the renal corpuscle to the distal tubule, the nephron loop, the proximal tubule, and into the collecting system.

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Textbook Question

Describe the structure of the filtration membrane.

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Textbook Question

Which of the following substances would pass through the filtration membrane to become part of the filtrate under normal circumstances? (Circle all that apply.)

a. Sodium ions

b. Albumin

c. Glucose

d. Erythrocytes

e. Leukocytes

f. Amino acids

g. Urea

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Textbook Question

Which of the following is false about the GFR?

a. The GFR averages about 120 ml/min