A&P Unit 3 Exam Flashcards

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Questions and Answers

Describe the bicarbonate buffer system and explain its importance in regulating pH changes.

The bicarbonate buffer system is a solution containing carbonic acid and sodium bicarbonate. When sodium bicarbonate comes in contact with a strong acid, carbonic acid and NaCl are formed. This process removes hydrogen ions, causing the pH to rise and become more basic.

Explain the renin-angiotensin-aldosterone mechanism.

Renin is released, activating angiotensinogen to angiotensin 1, then ACE converts it to angiotensin 2, resulting in constriction of blood vessels and a higher blood pressure.

Identify the four ways in which angiotensin II is able to increase blood pressure.

Adrenal cortex releases aldosterone. 2. Angiotensin activates thirst response. 3. Vasoconstriction. 4. Increased sodium reabsorption by the renal tubules.

Explain how aldosterone influences water balance in the body.

Aldosterone stimulates sodium reabsorption in the tubule cells (DCT). Water follows salt, increasing the amount of water returned to the body, especially when the body is dehydrated. Signup and view all the answers

Briefly explain how urine is concentrated.

The kidneys concentrate urine through the antidiuretic hormone (ADH), which increases water uptake and decreases urine output. This process involves osmosis through collecting ducts. Signup and view all the answers

Name two causes of metabolic acidosis and two causes of metabolic alkalosis.

Metabolic acidosis: Too much alcohol, accumulation of lactic acid during exercise; Metabolic alkalosis: Vomiting acidic contents of the stomach, intake of antacids. Signup and view all the answers

Explain the three ways PTH increases Ca2+ levels in the blood.

<ol> <li>Breaks down bones to release calcium and hydrogen phosphate. 2. Increases calcium reabsorption by renal tubules while decreasing phosphate ion reabsorption. 3. Enhances intestinal absorption of calcium by activating vitamin D.</li> </ol> Signup and view all the answers

Explain the three types of buffering systems in the body and rank them from fastest to slowest.

Chemical buffers act in a fraction of a second, respiratory buffers act within 1-3 minutes, and renal buffers usually require a day or more. Signup and view all the answers

What is the hydrostatic pressure in the glomerular capsule?

The chief force pushing water and solutes out of the blood and across the filtration membrane. Signup and view all the answers

What does hydrostatic pressure in the capsular space refer to?

Fluid pushing up on the capillaries. Signup and view all the answers

What is osmotic pressure in the glomerular capsule?

The minimum pressure needed to prevent the inward flow of pure solvent across a semipermeable membrane. Signup and view all the answers

Define net filtration pressure.

The difference between net hydrostatic pressure and net osmotic pressure minus the hydrostatic pressure. Signup and view all the answers

Study Notes

Bicarbonate Buffer System

Comprises carbonic acid and sodium bicarbonate.
Neutralizes strong acids by forming carbonic acid and NaCl, thereby raising pH and promoting basicity.

Renin-Angiotensin-Aldosterone Mechanism

Renin release activates angiotensinogen to produce angiotensin I.
Angiotensin I converts to angiotensin II via ACE, leading to blood vessel constriction and raised blood pressure.

Angiotensin II and Blood Pressure

Stimulates adrenal cortex to release aldosterone.
Activates thirst response to encourage fluid intake.
Causes vasoconstriction to increase vascular resistance.
Promotes renal tubules' sodium reabsorption, enhancing fluid retention.

Aldosterone and Water Balance

Stimulates sodium reabsorption in distal convoluted tubule (DCT).
Water follows absorbed sodium, conserving body water when hydration is low.

Urine Concentration and Survival Without Water

Antidiuretic hormone (ADH) elevates water uptake and reduces urine output.
ADH increases permeability of collecting duct membranes for water via osmosis.
Concentration occurs in the nephron loop and involves the medullary gradient.

Metabolic Acidosis and Alkalosis Causes

Metabolic Acidosis: Excess alcohol consumption, lactic acid buildup from exercise or shock.
Metabolic Alkalosis: Loss of stomach acid through vomiting, excessive antacid intake.

Parathyroid Hormone (PTH) and Calcium Levels

Promotes bone breakdown, releasing calcium and hydrogen phosphate.
Enhances calcium reabsorption in renal tubules while limiting phosphate reabsorption.
Stimulates kidney to convert vitamin D into its active form for better intestinal calcium absorption.

Buffering Systems in the Body

Chemical Buffering: Immediate response to pH changes; quickest line of defense.
Respiratory Buffering: Modulates breath rate and depth within 1-3 minutes to adjust blood pH.
Renal Buffering: Kidneys regulate pH changes; slower response, takes days for effects.

Hydrostatic Pressure in Glomerular Capsule

Primary force pushing water and solutes from blood across filtration membrane.

Hydrostatic Pressure in Capsular Space

Refers to fluid pressure exerted upward against the capillaries.

Osmotic Pressure in Glomerular Capsule

Minimum pressure necessary to prevent pure solvent from entering across a semipermeable membrane.

Net Filtration Pressure

Calculated by subtracting net osmotic pressure and hydrostatic pressure from net hydrostatic pressure.

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Description

Test your understanding of key concepts in Anatomy and Physiology with these flashcards focused on Unit 3. These include important topics like the bicarbonate buffer system and the renin-angiotensin system, essential for maintaining pH balance and blood pressure regulation.