A&P II Exam 4

What are the major macronutrients?

Carbohydrates, lipids, proteins.

What are the dietary sources of carbohydrates?

Plants (starch), sugars, insoluble fiber (cellulose), soluble fiber (pectin), small amounts in milk sugar and glycogen in meats.

What is the primary function of glucose?

Fuel most used by cells to make ATP.

What are the dietary sources of lipids?

Triglycerides (neutral fats): most abundant form

• Found in saturated fats in meat, dairy foods, tropical oils, or

hydrogenated oils (trans fats)

• Unsaturated fats found in seeds, nuts, olive oil, and most vegetable oils

Cholesterol found in egg yolk, meats, organ meats, shellfish, and milk products

What are the functions of lipids?

Adipose tissue offers protection, insulation, fuel storage, Phospholipids essential in myelin sheaths and all cell membranes, Cholesterol stabilizes membranes; precursor of bile salts, steroid hormones, Prostaglandins → smooth muscle contraction, BP control, inflammation, Help absorb fat-soluble vitamins, Major fuel of hepatocytes and skeletal muscle

What are the functions of proteins?

To provide structural materials and functional molecules

What do neurons and red blood cells rely on for their energy production?

Glucose

What are the most abundant dietary lipids?

Triglycerides

What are complete proteins?

Proteins that contain all needed essential amino acids.

What are essential amino acids?

Amino acids that must be eaten because the body cannot produce them.

What are the major micronutrients?

Vitamins and minerals.

What are the functions of vitamins?

Organic compounds crucial for helping the body use nutrients, most function as coenzymes.

What are the functions of minerals?

Work with nutrients to ensure proper body functioning

What is the source of vitamin A?

Beta-carotene from carrots, converted in the body into vitamin A

What is the source of vitamin D?

It is made in the skin

What is the source of vitamin B and K?

Some B and K synthesized by intestinal bacteria

What are the fat-soluble vitamins?

Vitamins A, D, E, and K.

What are the water-soluble vitamins?

Vitamins C and B.

Which vitamins are known to be antioxidants?

Vitamins A, C, and E.

Which mineral is essential for oxygen binding to hemoglobin?

Iron.

What is anabolism?

Synthesis of large molecules from small ones.

What is catabolism?

Hydrolysis of complex structures to simpler ones.

What are the two coenzymes that act as hydrogen acceptors in ATP production?

Nicotinamide adenine dinucleotide (NAD+) and Flavin adenine dinucleotide (FAD).

What are the three pathways of complete metabolism of glucose?

1. Glycolysis (anaerobic; 2 ATP)

2. Krebs cycle (aerobic, 2 ATP)

3. Electron transport chain and oxidative phosphorylation (aerobic, 26-28 ATP).

Which mechanism produces the most ATP during cellular respiration, substrate level phosphorylation or oxidative phosphorylation?

Oxidative phosphorylation.

What is gluconeogenesis?

Formation of glucose from noncarbohydrate precursors.

What is glycogenesis?

Polymerizes glucose to form glycogen

What is glycolysis?

Conversion of glucose to pyruvic acid.

What is glycogenolysis?

Hydrolysis of glycogen to glucose monomers.

What is lipogenesis?

Forms lipids from acetyl CoA and glyceraldehyde 3-phosphate

What is lipolysis?

Breakdown of lipids to fatty acids and glycerol.

What is transamination?

Transfers an amine group from an amino acid to alpha-ketoglutaric acid, generating glutamic acid

What is oxidative deamination?

Removal of an amine group from glutamic acid.

What is the major metabolic thrust of the post-absorptive state?

Catabolism and replacement of fuels in blood.

What is the major metabolic thrust of the absorptive state?

Anabolism and energy storage.

Which hormone directs the absorptive state?

Insulin.

Which hormone directs the post-absorptive state?

Glucagon.

What are the metabolic effects of diabetes mellitus?

Unavailability of glucose to cells, high blood glucose levels, glucose loss in urine, reliance on fats and proteins for energy.

What are the mechanisms of heat production?

Basal metabolism, muscular activity (shivering), thyroxine and epinephrine effects, temperature effects.

What are the characteristics of metabolic syndrome?

Increased waist circumference, increased blood pressure, increased blood glucose, increased blood triglycerides, decreased HDL cholesterol.

What are the functions of the kidneys?

Kidneys maintain the body’s internal environment by: Regulating water volume, total solute concentration, ion concentrations, acid-base balance, excrete metabolic wastes, produce erythropoietin and renin, activate vitamin D, and carrying out gluconeogenesis if needed.

What are the main organs of the urinary system?

Kidneys, ureters, urinary bladder, urethra.

How are the kidneys aligned in the abdominal cavity?

Right kidney is lower than left due to liver crowding.

What is the role of the fatty tissue surrounding the kidney?

Fatty tissue capsule that holds kidneys in normal position

What are the anatomical structures from the renal papilla to the bladder?

Renal papilla > minor calyces > major calyces > renal pelvis > ureter > bladder

What is the structural and functional unit of the kidney?

The nephron

In which kidney region are all renal corpuscles located?

Cortex

What two structures make up the renal corpuscle?

The glomerulus and the glomerular capsule

What is the difference between the renal corpuscle and the renal capsule?

The renal corpuscle is where blood plasma is filtered; the renal capsule is the fibrous outer covering of the whole kidney.

What are the parts of the kidney tubule and their primary functions?

Proximal convoluted tubule - reabsorption and secretion

Nephron loop - reabsorption

Distal convoluted tubule - functions more in secretion than reabsorption.

Which region of the kidney tubules contains microvilli and why?

The proximal convoluted tubule contains microvilli to increase surface area to maximize reabsorption.

What's the difference between a cortical nephron and a juxtamedullary nephron?

Cortical nephrons are almost entirely in the cortex

Juxtamedullary nephrons have nephron loops that deeply invade the medulla and are important for setting up the salinity gradient.

What are some unique properties of the glomerulus?

Fed and drained by arterioles; afferent arteriole enters and efferent arteriole leaves; Blood pressure in glomerulus is high because afferent arterioles are larger in diameter than efferent arterioles

Where is blood plasma filtered in the kidneys?

In the glomerulus of the renal corpuscle.

What is the juxtaglomerular apparatus?

It is where the distal portion of the ascending limb of the nephron loop passes between the afferent and efferent arterioles. Regulates rate of filtrate formation and blood pressure

What does the macula densa do?

They are chemoreceptors that sense NaCl content of the filtrate.

What do the granular cells do?

They act as mechanoreceptors to sense blood pressure in the afferent arteriole and release renin in response to low blood pressure.

What are the three major processes in urine formation?

Filtration, Reabsorption, Secretion.

What two main categories of substances do not pass through the filtration barriers in the renal corpuscle? What molecules do pass through?

Cells and proteins do not pass through; small molecules like glucose, amino acids, ions, and water do pass through.

What happens to net filtration if the hydrostatic pressure in the capsular space is increased?

Net filtration would decrease.

What would happen to net filtration if the hydrostatic pressure in the capsular space were significantly decreased below normal

Net filtration would increase

What is the glomerular filtration rate (GFR)?

GFR = volume of filtrate formed per minute by both kidneys (normal = 120–125 ml/min)

What is the primary focus of extrinsic controls of kidney glomerular filtration rate?

To maintain systemic blood pressure.

What is the primary focus of intrinsic controls of kidney glomerular filtration rate?

To maintain GFR in kidney

How does the myogenic mechanism maintain constant GFR?

• Local smooth muscle contracts when stretched

• Increased BP increases the GFR and causes muscle to stretch, leading to constriction of afferent arterioles

• This restricts blood flow into glomerulus thus bringing GFR back down

• Protects glomeruli from damaging high BP

• Decreased BP leads to decreased GFR which causes dilation of afferent arterioles to bring GFR back up

How does the tubuloglomerular feedback maintain constant GFR?

• If GFR increases, filtrate flow rate increases

• Leads to decreased reabsorption time, causing high NaCl levels in filtrate

• Feedback mechanism causes constriction of afferent arteriole, which lowers NFP and GFR, allowing more time for NaCl reabsorption

• Opposite mechanism for decreased GFR

How does an increase in sympathetic innervation of the kidneys affect urine output?

Sympathetic innervation decreases urine output

What is the renin-angiotensin-aldosterone mechanism?

The renin-angiotensin-aldosterone mechanism is the main mechanism for increasing blood pressure

A drop in blood pressure > granular cells release renin > angiotensin II is produced > causes vasoconstriction to raise blood pressure and causes release of aldosterone from the adrenal cortex > increases Na+ and water reabsorption to raise blood volume and blood pressure

What is the primary mechanism of glucose reabsorption in the kidneys?

Glucose is reabsorbed by secondary active transport, cotransported with Na+. It occurs in the proxmial convoluted tubule

Where in the nephron does most solute reabsorption occur?

Proximal convoluted tubule.

What is the difference in function of the ascending versus the descending limb of the nephron loop? Which is permeable to water? Which can transport solute?

The ascending limb can transport solute;  it sets up the concentration gradient for water to exit the descending limb

The descending limb is permeable to water; water exits the tubule by osmosis

What does antidiuretic hormone (ADH) do?

ADH increases water reabsorption by increasing the number of aquaporin water channels in the collecting duct which increases the permeability of the collecting duct to water,

What hormone increases water reabsorption in the collecting duct?

ADH

What hormone promotes potassium secretion and sodium absorption in the DCT and collecting ducts?

Aldosterone

What is countercurrent multiplication?

The interaction of filtrate flow in ascending/descending limbs of nephron loops that creates a salinity gradient for greater water reabsorption.

What is countercurrent exchange?

Blood flow in ascending/descending limbs of vasa recta that maintains the salinity gradient.

What structure of the kidney tubules is most important for urine concentration?

Nephron loop

How does the permeability of the collecting tubule to water relate to making more dilute or more concentrated urine?

Higher permeability of the collecting tubule to water increases reabsorption of water leading to a small volume of concentrated urine

Lower permeability of the collecting tubule to water decreases reabsorption of water leading to large volume of more dilute urine

What is an osmotic diuretic?

A substance not reabsorbed, causing water to remain in urine, such as high glucose in diabetes mellitus.

What muscle makes up the wall of the urinary bladder?

Detrusor

What type of muscle is the internal urethral sphincter?

Smooth muscle; involuntary control.

What type of muscle is the external urethral sphincter?

Skeletal muscle; voluntary control.

What is micturition?

The elimination of urine.

What defines renal failure?

Renal failure is defined as GFR < 15 ml/min

What are the major body fluid compartments? In which compartment of the body is the majority of water stored?

Intracellular – majority of water

Extracellular – interstitial fluid and blood plasma

What is the most common cation in interstitial fluid?

Na+ is most abundant

What is the most common cation in intracellular fluid?

K+ is most abundant

What are the major routes of fluid loss?

Feces, sweat, insensible loss via skin and lungs, and urine.

Which route accounts for most fluid loss per day?

Urine.

What is the normal osmolality range for body fluids?

280-300 mOsm.

What factors are involved in triggering the thirst mechanism?

Increased osmolality, dry mouth, decrease in blood volume.

What happens to cells in hypotonic hydration?

Cells swell.

What happens to cells in dehydration?

Cells shrivel (crenate).

What is hyponatremia?

Low levels of Na+.

What can cause hyponatremia?

Overhydration.

What are symptoms of hyponatremia?

Severe metabolic disturbances, nausea, vomiting, muscular cramping, cerebral edema, possible death.

To which ion is the body's water volume closely tied?

Sodium.

What homeostatic mechanisms are linked to Na+-water balance?

Blood pressure and blood volume control mechanisms.

What hormones lead to water retention?

Aldosterone, estrogen, glucocorticoids increase Na+ and water retention

Which hormone is associated with monthly cyclical changes?

Estrogen.