Chap 25/26/27

Question 1

What is HDL?

Answer 1

High-Density Lipoprotein, known as ‘good cholesterol.’

Function: Transports cholesterol from tissues to the liver for excretion or recycling.

Question 2

What is LDL?

Answer 2

Low-Density Lipoprotein, known as ‘bad cholesterol.’

Function: Transports cholesterol to tissues; excess can lead to plaque buildup in arterial walls.

Question 3

What does ATP stand for?

Answer 3

Adenosine Triphosphate

The primary molecule used for energy transfer in cells.

Question 4

What are the three main uses of glucose?

Answer 4

• Generate ATP (energy)
• Be stored as glycogen
• Be converted into amino acids for protein synthesis

Question 5

What occurs during glycolysis?

Answer 5

The complete breakdown of glucose into energy

Occurs in the cytoplasm, anaerobic, produces pyruvic acid, 2 ATP, and NADH.

Question 6

What is formed when pyruvic acid is converted in the mitochondria?

Answer 6

Acetyl Coenzyme A

This conversion requires oxygen.

Question 7

What does the Krebs Cycle produce?

Answer 7

• Reduced coenzymes (NADH, FADH2)
• CO2

Question 8

Where is the Electron Transport Chain located?

Answer 8

In the mitochondrial inner membrane

Uses NADH and FADH2 to generate most of the ATP (~28-32 ATP per glucose molecule).

Question 9

Define glycogenolysis.

Answer 9

Breakdown of glycogen to glucose for energy.

Question 10

What is gluconeogenesis?

Answer 10

Formation of glucose from non-carbohydrate sources (e.g., amino acids, glycerol).

Question 11

What is lipolysis?

Answer 11

Breakdown of triglycerides into glycerol and free fatty acids for energy.

Question 12

How are ketone bodies formed?

Answer 12

During lipolysis, excessive fatty acid breakdown in the liver generates acetyl-CoA, which is converted into ketone bodies.

Occurs in conditions like starvation, low-carb diets, or uncontrolled diabetes.

Question 13

How is excess energy stored in the body?

Answer 13

As triglycerides in adipose tissue for long-term energy needs.

Question 14

What vitamin is produced by E. coli in the intestines?

Answer 14

Vitamin K

Vitamin K is essential for blood clotting as a coenzyme.

Question 15

What is required as a coenzyme for blood clotting?

Answer 15

Vitamin K

It is produced by E. coli in the intestines.

Question 16

Which cells synthesize most of the body’s cholesterol?

Answer 16

Hepatocytes

Hepatocytes are liver cells responsible for cholesterol production.

Question 17

What must be obtained through diet as the body cannot produce them?

Answer 17

Essential Amino Acids

Essential amino acids are crucial for various bodily functions.

Question 18

What effect does eating have on metabolic rate?

Answer 18

Increases heat production and metabolic rate

This is due to the energy required for digestion, absorption, and storage.

Question 19

What acts as the body’s thermostat regulating temperature?

Answer 19

Hypothalamus

The hypothalamus also controls hunger, thirst, and other autonomic processes.

Question 20

What can kidneys perform during prolonged fasting?

Answer 20

Gluconeogenesis

This process synthesizes glucose from non-carbohydrate sources.

Question 21

What is reabsorbed in the proximal convoluted tubule (PCT)?

Answer 21

Filtered glucose

The PCT reabsorbs ~65% of solutes and water.

Question 22

What is the average glomerular filtration rate (GFR) for males?

Answer 22

~125 mL/min

For females, the average GFR is ~105 mL/min.

Question 23

What is filtered at the glomerular capsule?

Answer 23

Water, ions (Na, CI, K), glucose, amino acids

Large proteins and blood cells are not filtered due to size.

Question 24

What is the descending limb of the loop of Henle permeable to?

Answer 24

Water

Water is reabsorbed into the medulla due to the high osmotic gradient, concentrating the filtrate.

Question 25

What is actively reabsorbed in the ascending limb of the loop of Henle?

Answer 25

Sodium (Na*), potassium (K*), and chloride (Cl-) ## Footnote The ascending limb is impermeable to water, diluting the filtrate.

Question 26

Fill in the blank: The major site for solute and water reabsorption is the _______.

Answer 26

Proximal Convoluted Tubule (PCT) ## Footnote The PCT reabsorbs glucose, amino acids, Na*, CI, bicarbonate, and water.

Question 27

What is the primary function of the Distal Convoluted Tubule (DCT)?

Answer 27

Fine-tuning of water reabsorption, pH regulation, and removal of drug metabolites ## Footnote The DCT is involved in the regulation of water through the action of antidiuretic hormone (ADH) and in maintaining acid-base balance.

Question 28

Where is Aquaporin 1 located and what is its function?

Answer 28

Located in the descending limb of the nephron loop; facilitates water reabsorption ## Footnote Aquaporin 1 makes the descending limb highly permeable to water.

Question 29

What role does Aquaporin 2 play in the kidney?

Answer 29

Located in the DCT and collecting ducts; increases water reabsorption during dehydration ## Footnote Its activity is regulated by antidiuretic hormone (ADH).

Question 30

What does aldosterone stimulate in the DCT?

Answer 30

Na+ reabsorption and K+ excretion ## Footnote Aldosterone also increases water reabsorption, contributing to increased blood volume and pressure.

Question 31

How does Angiotensin II affect renal function?

Answer 31

Stimulates Na+ reabsorption in the PCT and triggers aldosterone release; constricts blood vessels to increase blood pressure ## Footnote This hormone plays a crucial role in regulating blood pressure and fluid balance.

Question 32

What is the function of the Na/K+ ATPase Pump in tubular cells?

Answer 32

Actively pumps Na+ out of tubular cells into the interstitial fluid ## Footnote This creates a gradient for Cl- and water to follow passively.

Question 33

What is Countercurrent Multiplication and where does it occur?

Answer 33

Occurs in the Loop of Henle; concentrates solutes in the medulla ## Footnote Na+ and Cl- are actively transported out of the ascending limb, pulling water out of the descending limb.

Question 34

What is the function of Countercurrent Exchange?

Answer 34

Maintains medullary osmotic gradient while allowing for gas, nutrient, and waste exchange ## Footnote This process occurs in the vasa recta, the capillaries surrounding the nephron loop.

Question 35

What percentage of total body water is intracellular fluid (ICF)?

Answer 35

Majority (~2/3) of total body water ## Footnote ICF is found inside cells, playing a critical role in cellular function.

Question 36

What does Extracellular Fluid (ECF) include?

Answer 36

Interstitial Fluid and Plasma ## Footnote Interstitial Fluid surrounds tissue cells (~80% of CF), while Plasma is the fluid portion of blood (~20% of ECF).

Question 37

What is the primary cation in Extracellular Fluid (ECF)?

Answer 37

Sodium (Na*) ## Footnote Sodium is key for fluid balance and nerve function.

Question 38

What is the primary anion in Extracellular Fluid (ECF)?

Answer 38

Chloride (Cl-) ## Footnote Chloride follows sodium for osmotic balance.

Question 39

What is the primary cation in Intracellular Fluid (ICF)?

Answer 39

Potassium (K*) ## Footnote Potassium is essential for cellular functions like muscle contraction and nerve impulses.

Question 40

What is the primary anion in Intracellular Fluid (ICF)?

Answer 40

Phosphate (HPO4^2-) ## Footnote Phosphate is involved in energy storage and buffering.

Question 41

What are the main sources of water for the body?

Answer 41

Ingested fluids ## Footnote Drinking water is a key source of water.

Question 42

How does water loss primarily occur?

Answer 42

Through urine ## Footnote Water loss is dependent on NaCl loss; water follows solutes like sodium and chloride due to osmosis.

Question 43

What is the role of Angiotensin II in water balance?

Answer 43

Stimulates Na* reabsorption in the kidney ## Footnote This increases blood volume and pressure.

Question 44

What does Aldosterone do?

Answer 44

Increases reabsorption of Na* and Cl- in the kidneys ## Footnote Aldosterone controls potassium (K*) excretion.

Question 45

What is the function of Atrial Natriuretic Peptide (ANP)?

Answer 45

Opposes aldosterone; promotes excretion of Na* and water ## Footnote This action lowers blood volume and pressure.

Question 46

What is the effect of Antidiuretic Hormone (ADH)?

Answer 46

Regulates water by increasing water reabsorption ## Footnote ADH acts in the DCT and collecting ducts via aquaporins.

Question 47

What are the major buffer systems in pH regulation?

Answer 47

Bicarbonate, Phosphate, and Proteins ## Footnote These buffers act quickly to resist pH changes.

Question 48

How does exhalation of carbon dioxide help maintain pH?

Answer 48

Removes CO2, reducing carbonic acid (H2CO3) formation ## Footnote This helps maintain a neutral pH.

Question 49

What is the role of the kidneys in acid-base homeostasis?

Answer 49

Excrete H* and reabsorb bicarbonate (HCO3-) ## Footnote This is the slowest but most effective method of pH regulation.

Question 50

True or False: Removing CO2 helps maintain a neutral pH.

Answer 50

True ## Footnote Removing CO2 reduces carbonic acid (H2CO3) levels.

Question 51

What are unique features of infant kidneys?

Answer 51

Limited urine concentration ## Footnote Infant kidneys are immature, making them more prone to dehydration.