26. Fluid and Electrolyte Balance, Acid Base Balance

Sodium balance, blood volume, and blood pressure regulation

Electrolyte Balance

Aldosterone: Sodium and Potassium Balance

 The most prevalent electrolyte in the extracellular fluid is sodium. 

 The most prevalent electrolyte in the extracellular fluid is __________. 

Reabsorption of sodium does not exhibit a transport maximum. In healthy individuals, nearly all sodium in the renal filtrate is reabsorbed in the proximal convoluted tubules of the kidneys. Atrial natriuretic peptide (ANP) and progesterone increase Na+ excretion. Progesterone appears to decrease NaCl reabsorption by blocking the effect aldosterone has on the renal tubules. Aldosterone is the key regulator of sodium reabsorption in the kidney. It encourages Na+ reabsorption. Estrogens, like aldosterone, encourage Na+ reabsorption. Glucocorticoids enhance tubular reabsorption of sodium.

 Which of the following would increase sodium excretion? 

the concentration of Na+ in blood plasma

The single most important factor that influences K+ secretion is the concentration of K+ in the ECF.

the concentration of K+ in the ECF

The most important factor that influences K+ secretion is __________.

 Electrolyte balance in the body usually refers to the balance of salts. 

 Electrolyte balance in the body usually refers to the balance of __________. 

Potassium Regulation

Calcium and Phosphate Regulation

Electrolytes are inorganic substances that dissociate into ions in water. Examples of electrolytes include salts [for example, sodium chloride (NaCl) and magnesium chloride (MgCl2)] and ions [for example, potassium (K+)]. Nonelectrolytes have bonds (usually covalent bonds) that prevent them from dissociating in water. Most nonelectrolytes are organic molecules. For example, glucose, lipids, urea, creatinine, and cholesterol are nonelectrolytes.

 Which of the following is NOT an electrolyte? 

 is released when aldosterone levels climb 

 PTH activates osteoclasts, which break down the bone matrix, releasing calcium. 

The most abundant cation (or positively charged ion) in the extracellular fluid (ECF) is sodium (Na+). The most abundant anion (or negatively charged ion) in the ECF is chloride (Cl–). The most abundant cation in the intracellular fluid (ICF) is potassium (K+). The most abundant anion in the ICF is hydrogen phosphate (HPO4–).

 The most abundant cation in extracellular fluid is potassium. 

Hypo- means low, and natrium is Latin for sodium.

 The condition in which sodium levels are too low is referred to as __________. 

Hormones in Body Fluid Homestasis

Sodium Regulation

 Excluding calcium stores sequestered inside organelles, intracellular calcium levels are very low. 

 Bicarbonate is an anion rather than a cation and intracellular bicarbonate levels are low. 

 While sodium is abundant in the interstitial fluid, the sodium-potassium pump keeps intracellular sodium levels relatively low. 

 While intracellular magnesium levels are higher than in interstitial fluid and blood plasma, intracellular magnesium levels are modest when compared to potassium. 

 What is the most abundant cation in intracellular fluid? 

Na+ is the only cation exerting significant osmotic pressure in the ECF.

 The only cation exerting significant osmotic pressure in the ECF is __________. 

 A major stimulus for the release of antidiuretic hormone is a rise in plasma osmolality. ADH results in increased water reabsorption. 

 an increase in potassium levels in the ICF 

 A major stimulus for the release of antidiuretic hormone is __________. 

Parathyroid hormone (PTH) is released in response to low Ca2+ levels. PTH causes the release of Ca2+ from the bones, increases absorption of Ca2+ by the small intestine, and increases calcium reabsorption in the proximal convoluted tubule of the kidneys.

Parathyroid hormone (PTH) increases Ca2+ deposition in the bones.

 ANP reduces blood pressure and blood volume by inhibiting nearly all events that promote vasoconstriction, sodium retention, and water retention. 

 decreased sodium and water reabsorption 

 increased antidiuretic-hormone secretion 

 When atrial natriuretic peptide is released by the heart because of increased blood pressure, it causes __________. 

When the concentration of Na+ in the ECF decreases, there is an increase in the level of aldosterone, which causes facultative Na+ reabsorption.

When the concentration of Na+ in the ECF decreases, __________.

 Antidiuretic hormone (ADH) acts on the kidneys to decrease water excretion. When ADH levels are high, most or all of the filtered water is reabsorbed and a small amount of concentrated urine is excreted. When ADH levels are low, less water is reabsorbed and dilute urine is excreted. 

 Antidiuretic hormone (ADH) acts on the __________ to __________ water excretion. 

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Anatomy & Physiology

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1. Introduction to A&P

2. Chemistry

3. Cells

4. Tissues

5. Integumentary System

6. Bones + Skeletal Tissues

7. Skeletal System

8. Joints

9. Muscles and Muscle Tissue

10. Muscular System

11. Nervous Tissue

12. Central Nervous System

13. Peripheral Nervous System

14. Autonomic Nervous System

15. Special Senses

16. Endocrine System

17. Blood

18. Cardiovascular System: the Heart

19. Cardiovascular System: Blood Vessels

20. Lymphatic System

21. Immune System

22. Respiratory System

23. Digestive System

24. Nutrition, Metabolism, Energy Balance

25. Urinary System

27. Reproductive System

28. Pregnancy and Human Development

29. Heredity

undefined - Channels

Potassium, calcium, and anion balance regulation

Major chemical buffer systems and pH change resistance

Influence of the respiratory system on acid-base balance.

Renal regulation of hydrogen and bicarbonate ion concentrations

Respiratory and metabolic acidosis and alkalosis

Respiratory and renal compensations acid-base balance maintenance

Acid-Base Balance

Body water content

Fluid compartments

Fluid shifts

Water routes

Water intake regulation and hormonal controls of water output

Dehydration and hypotonic hydration

Fluid Balance

General Chemistry