CSN 224 - LAB QUIZ 4

What are nutrients

Substances used by the body to produce energy, provide buildng blocks, or function in other chemical reactions

Which four nutrient classes are required by the body in large amounts

Carbohydrates

Lipids

Protein

Water

What two nutrient classes are required by the body in small amounts

Vitamins

Minerals

What defines an essential nutrient

A nutrient the must be INGESTED becasue it cannot be synthesized in the body

Energy yield per gram carbohydrates, proteins, lipids

Carbohydrates - 4g

Protein - 4g

Lipids - 9g

What is the primary dietary source of carbohydrates and what is the major exception

Most carbohydrates come from plants; the major exception is LACTOSE, which comes from milk

What monosaccharies are involved in dietary carbohydrates

glucose

fructose

galactose

What disaccharides are included in dietary carbohydrates

Sucrose

Maltose

Lactose

Which complex polysaccharies are included in human nutrition, and which one is indigestible

Cellulose is indigestible, glycogen, and starch

Into what compound are ingested disaccharides and polysaccharides converted for energy or storage

GLUCOSE, used for immediate energy or stored as glycogen or fats

Percent daily values on nutrition lables are based on a daily energy consumption of

2000 kcal/day

What is the primary for of dietary lipid, and what are its chemical constitutes

Triglycerides (95%) composed of glycerol plus fatty acids

How do saturated fats differ structurally from unsaturated fats

Saturated - contain single covalent bond

Unsaturated - contain one or more double bonds

What is the structural different between monosaturated and polyunsaturated fats

Monounsaturated - have one double bond

Polyunsaturated - two or more double bond

What type of lipid is cholesterol, and where is it found

Cholesterol is a steroid found in liver and egg yolks; it is not found in plants

What are the five key functional categories of proteins in the body?

Protection (antibodies)

Regulation (enzymes, hormones)

Structure (collagen)

Muscle contraction (actin, myosin)

Transportation (hemoglobin, ion channels)

What is the primary physiological role of phospholipids such as lecithin

They serve as major components of plasma membranes

What physiological functions do eicosanoids perform

Mediation of inflammation

Blood clotting

Tissue repair

Smooth muscle contraction

Out of 20 standard amino acids, how many are essential in the human diet

8 must be ingested, remaining 12 can be synthesized

What distinguishes complete proteins from incomplete proteins

Complete proteins - contain all essential amino acids (animal proteins)

Incomplete proteins - lack some essential amino acids (plant proteins)

What is a provitamin

A precursor substance that can be assembled by the body into a functioning vitamin

Which vitamins are water soluble, and how is their excess handled by the body

Vitamins B and C, excess amounts are readily excreted in urine

Which vitamins are fat soluble, and how are they absorbed and stored

Vitamins A, D, E, and K. They are ABSORBED from the GI tract withing micelles and STORED in fat (which can cause toxicity if taken in excess)

What is the primary physiological function of Vitamin A

It serves as a precurose of visual pigment in the retina

What is the primary physiological function of Vitamin D

It forms CALCITRIOL, which increases calcium absorbtion from the GI tract

What is the primary physiological function of Vitamin E

It acts as an antioxidant that stabilizes and prevents damage to cell membranes

What is the primary physiological function of Vitamin K

It is required for the synthesis of blood clotting proteins

What daily dietary intake threshold distinguishes major minerals from trace minerals

Major minerals - 100mg or more daily

Trace minerals - 100mg or less daily

What are clinical symptoms of calcium ion deficiency and excess

DEFICIENCY:

• osteoporosis

• muscle spasms

• nerve dysfunction

EXCCESS:

• kidney stones

• heart rhythm disturbances

• muscle weakness

What disorder is caused by a dietary deficiency in iron

Iron deficiency anemia (due to impaired hemoglobin synthesis)

What thyroid condition results from a dietary deficiency in iodine

Hyoothyroidism (Iodine is required for thyroid hormone synthesis)

How do catabolism and anabolism differ in energy coupling

Catabolism: energy releasing (exergonic) process breaking large molecules into smaller ones

Anabolism: energy requiring (endergonic) process joining small molecules to form larger ones

What is the net yield of products from one molecule of glucose during glycolysis

• 2 ATP

• 2 Pyruvate

• 2 NADH

What occurs during intermediate step between glycolysis and the citric acid cycle

2 pyruvate molecules are OXIDIZED to two acetyl-CoA, yielding two NADH

What are the yield products of the citric acid cycle per glucose molecule molecule (two acetyl-CoA)

• 6 NADH

• 2 FADH2

• 2 ATP

How does the ETC generate a proton gradient

Electrons from NADH and FADH2 pass through the ETC, powering the pumping of H+ ions into the intermembrane space

What is the theoretical total yield of ATP generated per glucose molecule during complete aerobic respiration

38 ATP (2 from glycolysis, 2 from citric acid cycle, 34 from oxidative phosphorylation)

By what catabolic pathway are free fatty acids converted into acetyl CoA for cellular respiration

B-oxidation (beta oxidation)

What is ketogeneis, where does it take place, and how are ketone bodies utilized?

Ketogenesis is the conversion of free fatty acids to ketone bodies in the liver. Ketones travel to skeletal muscle to enter the citric acid cycle for ATP production.

During protein catabolism, what process converts toxic ammonia into a form excreted by the kidneys

Oxidative deamination produces ammonia as a byproduct, which is converted to urea and excreted

What is the metabolic rate and how is it clinically estimated

The total amount of energy produced and used by the body per unit of time. It is estimated by the amount of oxygen used per minute.

What are the three compounds of daily metabolic energy expenditure and their respective percentage contributions

• Basal metabolic rate (BMR): 60%

• Muscular activity: 30%

• Thermic effect of food: 10%

What percentage of free energy liberated by food catabolism is trapped in ATP versus lost as heat?

43% is captured to produce ATP; the remaining 57% is lost as heat

How does the nervous system respond via the hypothalamus when body tempature rises above normal?

The heat loss center in the hypothalamus is activated, causing peripheral skin blood vessels to dialate and sweat glands to secrete sweat

How does thyroid hormone act to restore body tempature when core tempature drops?

Hypothalamus releases —> thyrotropin releasing hormone —> triggering thyroid hormone release, which increases the metabolic rate of all the body cells to raise tempature

What are the six major physiological functions of the kidneys

1. Excretion of waste products

2. Regulation of blood volume and pressure

3. Regulation of blood solute concentrations

4. Regulation of extracellular fluid pH

5. Regulation of RBC synthesis

6. Regulation of vitamin D synthesis

Between which vertebral levels are the kidneys anatomically located?

Between the levels of T12 and L3 vertebrae on the POSTERIOR abdominal wall

What are the three supportive layer coverings surrounding the kidney form, OUTERMOST to INNERMOST

• Renal fascia (dense fibrous outer layer)

• Perinephric fat/adipose capsule (thick fat layer)

• Fibrous capsule (collage fiber layer)

Name three endocrine metabolic molecules produced directly by the kidneys

• Calcitriol

• Erythropoietin

• Glucose (via glucogenesis)

What percentage of total cardiac output do the kidneys recieve under resting conditions

20-25% (approx. 1200m/min of blood flow)

What is the correct sequence of arterial blood flow into the kidney cortex?

1. Renal artery

2. Segmental artery

3. Interlobar artery

4. Arcuate artery

5. Interlobular artery

6. Afferent arteriole

7. Glomerulus

What is the correct sequence of venous drainage from the nephron back to the renal vein

Pertibular capillaries —> interlobular vein —> Arcuate vein —> Interlobar vein —> Renal vein

What functional characteristic distinguishes juxtamedullary nephrons from cortical nephrons

Juxtamedullary nephrons have long loops extending deep into medulla and are controlled more extensively by ADH to concentrate urine

What relative percentages of total nephrons are cortical versus juxtamedullary nephrons

Cortical - 85%

Juxtamedullary - 15%

What speacialized cells form the visceral layer of the glomerular capsule wrapping around glomerular capillaries?

Podocytes

What feature of glomerular capillary endothelium restricts the passage of blood cells into filtrate?

Fenestration (pores) in the endothelium

What are the two cellular components of the juxtaglomerular apparatus (JGA)

1. Juxtaglomerular (granular) cells

2. Macula densa cells

What is the primary function of JG cells

They synthesize, store, and release RENIN when stimulated by stretch or sympathetic activity

What is the primary function of macula densa cells in the distal convoluted tubule

They detect changes in NaCl concentration of luminal fluid and signal JG cells via paracrine stimulation to release renin

What is the net filtration pressure (NFP) calue driving fluid out of the glomerulus into bowmans capsule

10mmHG

Which vessel diameter arrangement maintains high hydrostatic pressure inside glomerular capillaries?

Low resistance (wide diameter) in afferent arterioles combined with high resistance (narrow diameter) in efferent arterioles.

How does sympathetic nerve stimulation affect kidney afferent arterioles and GFR

It causes constriction of afferent arteriole and glomeruli, decreasing GFR

How do sympathetic and parasympathetic stimulation differ in their effect on the urinary bladder muscle

Sympathetic stimulation relaxes the urinary bladder (detrusor); parasympathetic stimulation contracts the urinary bladder

Internal urethral control mechanism

The internal urethral sphincter is INVOLUNTARY (smooth muscle, contracted by sympathetic, relaxed by parasympathetic)

External urethral sphincter control mechanism

VOLUNTARY, skeletal muscle

At what urinary bladder volume is the concious desire for urination typically triggered

500mL

What is the absolute minimum daily urine volume required to prevent accumulation of metabolic wastes in blood

0.5L/day (wastes accumulate if volume drops below 0.4L/day)

What are primary organs responsible for daily water gain and water loss?

Primary source of water gain: Digestive system

Primary route of water loss: Urinary system

Electrolyte

An inorganic compoud that dissociates in solution into ions capable of conducting an electrical current

How do the kidneys and lungs collaborate to maintain acid-base balance

Kidneys: secrete H+ into urine

Lungs: eliminate CO2 to regulate blood H+ concentration

When water loss exceeds water gain in dehydration, what shift in water occurs between ICF and ECF

ECF osmotic concentration rises, causing water to move by osmosis from ICF into the ECF

What are four common physiological causes of dehydration

1. Excessive sweating

2. Inadequate water consumption

3. Repeated vomiting

4. Diarrhea

What cellular change occurs during hyper-hydration (water intoxication)

Excess water shifts from hyper-diluted ECF into the ICF, causing cells to swell and disrupting cell functions

How does hypertonic plasma affect cell volume?

The high osmotic pressure of hypertonic plasma draws water out of the cytosol into ECF, causing the cell to shrink

How does hypotonic plasma affect cell volume?

Low osmotic pressure in hypotonic plasma drives water from ECF into cytosol, causing the cell to swell.

What sensory receptors and system activate the hypothalamic thirst response when plasma volume drops?

Arterial baroreceptors detect decreased blood pressure, and renal JG cells detect reduced pressure to activate RAAS, triggering thirst in the hypothalamus.

Under normal physiological conditions, what proportion of filtered glucose and amino acids is reabsorbed from the tubular lumen by the proximal convoluted tubule (PCT)

100% glucose, 100% amino acids

How are continuous water evaporation through the skin surface and activate sweat secretion categorized with respect to physiological water loss?

Cutaneous evaporation is categorized as insensible water loss, whereas active sweating (persipiration) is categorized as sensible water loss.

Which specialized epithelial cells form the visceral layer of the glomerular capsule by wrapping directly around the glomerula capillaries

Podocytes

In the carbohydrate respiration balance presented in the course materials, how many of the total 38 ATP generated per glucose molecule are produced specifically by the electron transport chain and oxidative phosphorylation?

34 ATP

During the mitochondrial β-oxidation of free fatty acids, which set of molecules is directly generated to support ATP production?

• Acetyl-CoA

• NADH

• FADH2

Which component of the glomerular filtration membrane specifically prevents the passage of large plasma proteins into the capsular space?

The basement membrane

Which specific sensory receptors directly monitor an increase in plasma osmolarity above the normal range to activate the hypothalamic thirst center?

Osmoreceptors in hypothalamus

How does the myogenic autoregulation mechanism in the kidney respond when a person experiences a sudden spike in systemic blood pressure?

Afferent arterioles constrict in response to stretch, decreasing blood flow into glomerulus to keep GFR stable