A&P 2 quiz 4

summary of cellular respiration

1) The complete oxidation of glucose can be represented as follows: C6H12O6 + 6O2 => 36 or 38ATP + 6CO2 +6H2O 2) During aerobic respiration, 36 or 38 ATPs can be generated from one molecule of glucose. Two of those ATPs come from substrate-level phosphorylation in glycolysis and two come from substrate-level phosphorylation in the Krebs cycle.

glomerular filtration

The fluid that enters the capsular space is termed glomerular filtrate.The fraction of plasma in the afferent arterioles of the kidneys that becomes filtrate is termed the filtration fraction

reabsorption and secretion in the late DCT

The secretion of K+ here is the main source of K+ that is excreted in urine. The amount secreted is variable

Krebs cycle (citric acid cycle)

series of reactions that occur in the matrix of mitochondria 1) In each turn of the Krebs cycle, 6 NADH, 6 H+, and 2 FADH2 are produced by oxidation-reduction reactions, and two molecules of ATP are generated by substrate-level phosphorylation 2) The energy originally in glucose and then pyruvic acid is primarily in the reduced coenzymes NADH + H+ and FADH2

metabolism in the postabsoprtive state

stimulated by the presence of glucagon, epinephrine 1. With absorption complete, energy needs must be satisfied by nutrients already present in the body to maintain normal blood glucose level. (this especially important for the nervous system and red blood cells)

metabolism in the absorptive state

stimulated by the presence of insulin a. Glucose: oxidized to produce ATP or transported to the liver & converted to glycogen or triglycerides. b. Lipids: Most dietary lipids are stored in adipose tissue. c. Proteins: Amino acids

mechanisms of ATP generation

substrate-level phosphorylation, oxidative phosphorylation, or photophosphorylation (this occurs in chlorophil containing plants)

kidney functions

Kidneys contribute to homeostasis of body fluids by regulation of blood ionic composition, regulation of pH, regulation of blood volume, regulation of blood pressure, maintenance of blood osmolarity, producing hormones, regulating blood glucose level, and excreting wastes and foreign substances

electron transport chain

1) The electron transport chain involves a sequence of electron carrier molecules on the inner mitochondrial membrane, capable of a series of oxidation-reduction reactions. a) As electrons are passed through the chain, there is a stepwise release of energy from the electrons for the generation of ATP. b) In aerobic cellular respiration, the last electron receptor of the chain is molecular oxygen (O2). This final oxidation is irreversible. 2) The process involves a series of oxidation-reduction reactions in which the energy (as electrons) in NADH + H+ and FADH2 is passed along a series of electron carriers. This energy is used to pump H+ into the space between the inner and outer mitochondrial membranes, creating an electrochemical gradient of H+. This is called chemiosmosis. The energy given up as the H+ then goes down it's gradient, is used to make ATP from ADP

the nephron

1. A nephron consists of a renal corpuscle where fluid is filtered, and a renal tubule into which the filtered fluid passes 2. Nephrons perform three basic functions: glomerular filtration, tubular reabsorption, and tubular secretion. 3. A renal tubule consists of a proximal convoluted tubule (PCT), loop of Henle, & distal convoluted tubule (DCT). DCTs of several nephrons drain into one collecting duct and many collecting ducts drain into a small number of papillary ducts.

reabsoption routes

1. A substance being reabsorbed can move between adjacent tubule cells (paracellular reabsorption) or through an individual tubule cell before entering a peritubular capillary (transcellular absorption) 2. Fluid leakage between cells is known as paracellular reabsorption.

reabsorption in the early DCT

1. As fluid flows along the DCT, reabsorption of Na+ and Cl- continues due to Na+-Cl- symporters. 2. The DCT serves as the major site where parathyroid hormone stimulates reabsorption of Ca+2. 3. The solutes are reabsorbed with little accompanying water.

protein catabolism

1. Before amino acids can be catabolized, they must be converted to substances that can enter the Krebs cycle. These conversions involve deamination, and the NH3 (ammonia) is converted by the liver to urea and excreted. 2. Amino acids can be converted into glucose, fatty acids, and ketone bodies.

metabolism during fasting and starvation

1. Fasting: going without food for many hours or a few days. 2. Starvation: weeks or months of food deprivation or inadequate food intake. 3. Catabolism of stored triglycerides and structural proteins can provide energy for several weeks. 4. During fasting and starvation, nervous tissue and red blood cells continue to use glucose for ATP production. 5. During prolonged fasting, large amounts of amino acids from tissue protein breakdown (mostly skeletal muscle) are released & converted to glucose in the liver by gluconeogenesis. 6. The most dramatic metabolic change that occurs with fasting and starvation is the increase in formation of ketone bodies by hepatocytes. a. Ketogenesis increases as catabolism of fatty acids rises. b. the presence of ketones actually reduces the use of glucose for ATP production, which in turn decreases the demand for gluconeogenesis and slows the catabolism of muscle proteins.

filtration membrane

1. Filtered substances move from the blood stream through three barriers: a glomerular endothelial cell, the basal lamina, and a filtration slit formed by a podocyte 2. The principle of filtration - to force fluids and solutes through a membrane by pressure - is the same in glomerular capillaries as in capillaries elsewhere in the body. 3. The three features of the renal corpuscle that enhance its filtering capacity include the large surface area across which filtration can occur, the thin and porous nature of the filtration membrane, and the high level of glomerular capillary blood pressure.

net filtration pressure

1. Filtration of blood is promoted by glomerular blood hydrostatic pressure (GBHP) and opposed by capsular hydrostatic pressure (CHP) and blood colloid osmotic pressure (BCOP). The net filtration pressure (NFP) is about 10 mm Hg. 2. In some kidney diseases, damaged glomerular capillaries become so permeable that plasma proteins enter the filtrate

glucose catabolism

1. Glucose oxidation, also called cellular respiration, occurs in every cell of the body (except red blood cells, which lack mitochondria) & provides the cell's chief source of energy (ATP). 2. The complete oxidation of glucose to CO2 and H2O produces large amounts of energy and occurs in four successive stages: glycolysis, formation of acetyl coenzyme A, the Krebs cycle, and the electron transport chain

hormonal static regulation

1. Hormones affect the extent of Na+, Cl-, & H2O reabsorption & K+ secretion 2. In the renin-angiotensin-aldosterone system, angiotensin II increases reabsorption of Na+ and water thus increases blood volume 3. Aldosterone: increases reabsorption of Na+ & water in the collecting duct & the secretion of K+. 4. Antidiuretic hormone (ADH): regulates water reabsorption by increasing the water permeability of principal cells in the collecting duct 5. Atrial natriuretic peptide (ANP): increases loss of Na+ and water. 6. Parathyroid hormone: promotes Calcium reabsorption

internal anatomy of kidney

1. Internally, the kidneys consist of cortex, medulla, pyramids, papillae, columns, calyces, and renal pelves 2. The renal cortex and renal pyramids constitute the functional portion or parenchyma of the kidney. 3. The nephron is the functional unit of the kidney. The number of nephrons is constant from birth. They may increase in size, but not in number

reabsorption in loop of henle

1. Na+, Cl-, and K+ ions are reabsorbed 2. Although about 15% of the filtered water is reabsorbed in the descending limb.

external anatomy of kidney

1. Near the center of the concave medial border of the kidney is a vertical fissure called the hilus, through which the ureter leaves and blood vessels, lymphatic vessels, and nerves enter and exit. 2. Three layers of tissue surround each kidney: the innermost renal capsule, the adipose capsule, and the outer renal fascia.

principles of tubular reabsorption

1. Reabsorption returns most of the filtered water and many of the filtered solutes to the bloodstream using both active and passive transport processes. 2. Tubular secretion, the transfer of materials from the blood and tubule cells into tubular fluid, helps control blood pH and helps eliminate other substances from the body.

transport mechanism

1. Solute reabsorption drives water reabsorption. The mechanisms that accomplish Na+ reabsorption in each portion of the renal tubule and collecting duct recover not only filtered Na+ but also other electrolytes, nutrients, and water. 2. Transport across membranes can be either active or passive a. In primary active transport the energy derived from ATP is used to "pump" a substance across a membrane. b. In secondary active transport the energy stored in an ion's electrochemical gradient drives another substance across the membrane. Solutes are transported via symporters or antiporters c. When the blood concentration of glucose is above 200 mg/mL, the renal symporters cannot work fast enough to reabsorb all the glucose that enters the glomerular filtrate. As a result, some glucose remains in the urine, a condition called glucosuria. 3. The mechanism for water reabsorption by the renal tubule and collecting duct is osmosis. This accounts for about 90% of reabsorption of water. (water follows the solutes) a. Water reabsorption together with solutes in tubular fluid is called obligatory water reabsorption. This primarily occurs in the PCT. b. Facultative reabsorption: based on need and occurs in the collecting ducts and is regulated by ADH.

glucose anabolism

1. The conversion of glucose to glycogen for storage in the liver and skeletal muscle is called glycogenesis. The process occurs is stimulated by insulin 2. The conversion of glycogen back to glucose is called glycogenolysis. This process occurs between meals and is stimulated by glucagon and epinephrine 3. Gluconeogenesis is the conversion of protein or fat molecules into glucose. This process is stimulated by cortisol, thyroid hormone, epinephrine, glucagon, and human growth hormone.

protein metabolism

A. During digestion, proteins are hydrolyzed into amino acids. Amino acids are absorbed by the capillaries of villi and enter the liver via the hepatic portal vein. B. Fate of Proteins 1. Amino acids, under the influence of human growth hormone and insulin, enter body cells where they are synthesized into proteins. They may also be stored as fat or glycogen or used for energy.

metabolic adaptations

A. Metabolic reactions depends on how recently you have eaten. During the absorptive state, which alternates with the postabsorptive state, ingested nutrients enter the blood and lymph from the GI tract, and glucose is readily available for ATP production. 1. An average meal requires about 4 hours for complete absorption, given 3 meals a day, the body spends about 12 hours a day in the absorptive state. The other 12 hours are spent in the postabsorptive state. 2. Hormones are the major regulators of reactions during each state.

homeostatic production of dilute

A. The rate at which water is lost from the body depends mainly on ADH, which controls water permeability of principal cells in the collecting duct (and in the last portion of the distal convoluted tubule). B. When ADH level is very low, the kidneys produce dilute urine and excrete excess water C. When ADH level is high, the kidneys secrete concentrated urine and conserve water; a large volume of water is reabsorbed and the solute concentration of urine is high.

urine storage, transportation, and elimination

A. Urine drains through papillary ducts into minor calyces, which joint to become major calyces that unite to form the renal pelvis. From the renal pelvis, urine drains into the ureters and then into the urinary bladder, and finally, out of the body by way of the urethra B. Ureters: transport urine from the renal pelvis to the urinary bladder, primarily by peristalsis, but hydrostatic pressure and gravity also contribute. C. Urinary Bladder: a hollow muscular organ situated in the pelvic cavity D. Micturition Reflex: Urine is expelled from the urinary bladder. (also called voiding) When the volume of urine in the bladder reaches a certain amount (usually 200-400 ml), stretch receptors in the urinary bladder wall transmit impulses that initiate a spinal micturition reflex. The detrusor muscle contracts and the internal urethral sphincter (involuntary) & external urethral sphincter (voluntary) relax. Also under voluntary control. E. Urethra: a tube leading from the floor of the urinary bladder to the exterior. Its function is to discharge urine from the body. The male urethra also serves as the duct for ejaculation of semen

evaluation of kidney function

An analysis of the volume and physical, chemical, and microscopic properties of urine, called urinalysis, reveals much about the state of the body. Glucose, protein, microbes, ketones and red blood cells should not be found in the urine

carbohydrate metabolism

During digestion, polysaccharides and disaccharides are converted to monosaccharides (primarily glucose), which are absorbed through capillaries in villi and transported to the liver via the hepatic portal vein

homeostasis of GFR

Glomerular filtration rate (GFR) is the amount of filtrate formed by both kidneys per minute; in a normal adult, it is about 125 ml/minute. This amounts to 180 liters per day. a. GFR is directly related to the pressures that determine net filtration pressure. b. Three mechanisms regulate GFR; they adjust blood flow into and out of the glomerulus & alter the glomerular capillary surface area available for filtration. The 3 mechanisms are renal autoregulation, neural regulation, and hormonal regulation.

glucose movement into cells

Glucose movement from blood into most body cells occurs via facilitated diffusion transporters (Glu-T molecules). Insulin increases the insertion of Glu-T molecules into the plasma membranes, thus increasing the rate of facilitated diffusion of glucose

mechanisms of heat transfer

Heat is lost from the body by radiation, evaporation, conduction, and convection

body temperature homeostasis

If the amount of heat production equals the amount of heat loss, one maintains a constant core temperature near 370C (98.60F)

homeostasis of blood volume and composition

Nephrons perform 3 basic processes while producing urine: glomerular filtration, tubular secretion, and tubular reabsorption. By altering these processes, nephrons maintain homeostasis of blood

formation of Acetyl coenzyme A

Pyruvic acid is prepared for entrance into the Krebs cycle by being converted into acetyl coenzyme A

reabsorption and secretion in the PCT

The majority of solute and water reabsorption from filtered fluid occurs in the proximal convoluted tubules and most absorptive processes involve Na+. B. 100% of filtered glucose, lactic acid, amino acids, water soluble vitamins; 80-90% of bicarbonate ions; 65% of water, Na+, and K+; 50% of Cl-; and a variable amount of Ca+2, Mg+2, and HPO4-2 are absorbed. C. Reabsorption of Na+ and other solutes creates an osmotic gradient that promotes reabsorption of water by osmosis. D. Urea and ammonia in the blood are both filtered at the glomerulus and secreted by the proximal convoluted tubule cells into the tubules.

metabolic rate

The overall rate at which heat is produced. Measurement of the metabolic rate under basal conditions is called the basal metabolic rate (BMR). This is the rate at which the quiet, resting, fasting body breaks down nutrients to liberate energy

3 major metabolic destinations for nutrients will be?

They will be used for energy for active processes, synthesized into structural or functional molecules, or synthesized as fat or glycogen for later use as energy

lipolysis

Triglycerides are split into fatty acids and glycerol under the influence of hormones such as epinephrine, norepinephrine, and glucagon

pyruvic acid depends on oxygen

When oxygen is in short supply, pyruvic acid is reduced to lactic acid. When oxygen is present, pyruvic acid is converted to acetyl coenzyme A and enters the Krebs cycle

heat production

a. Factors that affect metabolic rate include exercise, hormones, the nervous system, body temperature, ingestion of food, age, and other factors such as gender, climate, sleep, and malnutrition. b. Factors that regulate heat production & loss include: vasoconstriction, sympathetic stimulation, skeletal muscle contraction (shivering), and thyroid hormone production.

renal auto regulation of GFR

a. Myogenic mechanism: stretching causes contraction of smooth muscle cells in the wall of the afferent arteriole. This then decrease GFR. b. Tubuloglomerular feedback: solute concentration increases in the tubules. The macula densa senses this, causes a decrease in the relase of NO and therefore, contraction of the afferent arteriole & decreased GFR. 2. Neural regulation of GFR: ANS fibers release norepinephrine causing vasoconstriction. 3. Hormonal regulation of GFR: action of angiotensin II and atrial natruiretic peptide.

renal tubule and collecting duct

a. The juxtaglomerular apparatus (JGA) consists of the juxtaglomerular cells of an afferent arteriole and the macula densa. The JGA helps regulate blood pressure and the rate of blood filtration by the kidneys b. PCT: cuboidal cells, DCT: principal and intercalated cells

glycolysis

breakdown of the six-carbon molecule, glucose, into two three-carbon molecules of pyruvic acid & produces 2 ATP

LDL

carry about 75% of total blood cholesterol from the liver and deliver it to cells throughout the body. When present in excessive numbers, LDLs deposit cholesterol in and around smooth muscle fibers in arteries. "bad cholesterol"

chylomicrons

carry exogenous (dietary) lipids from the intestine via to lymph fluid (lacteals), to the systemic circulation (liver, adipose tissue)

catabolism

chemical reactions that break down complex organic molecules

anabolism

chemical reactions that combine simple molecules to form complex molecules

glomerular capsule

consists of visceral and parietal layers a. Visceral layer: modified simple squamous epithelial cells called podocytes. b. Parietal layer: simple squamous epithelium, forms the outer wall of the capsule. c. Fluid filtered from the glomerular capillaries enters the capsular space, the space between the two layers of the glomerular capsule.

VLDL

contain endogenous triglycerides. Transport triglycerides made in hepatocytes to adipocytes for storage as well as other body cells. (VLDLs converted to LDLs)

lipogenesis

conversion of glucose or amino acids into lipids. The process is stimulated by insulin

fate of glucose

glucose is the body's preferred source for synthesizing ATP. If the cells require immediate energy, glucose is oxidized by the cells to produce ATP. Glucose can also be used to form amino acids, stored by the liver and skeletal muscles as glycogen, (glycogenesis), converted by liver cells and fat cells can to glycerol and fatty acids that can be used for synthesis of triglycerides (lipogenesis)

postabsoprtive state reactions

glucose production & alternative fuel sources a. glucose production: breakdown of liver glycogen, gluconeogenesis using lactic acid, amino acids & glycerol from triglycerides b. Reactions that produce ATP without using glucose are oxidation of fatty acids, lactic acid, amino acids, ketone bodies, & glycogen from skeletal muscle

hypothalamus

houses the body's thermostat & receives information from the body's thermoreceptors. a. The hypothalmic thermostat is the preoptic area. b. Nerve impulses from the preoptic area propagate to other parts of the hypothalamus known as the heat-losing center and the heat-promoting center.

fatty acids

in beta oxidation, carbon atoms are removed in pairs from fatty acid chains resulting in molecules of acetyl coenzyme A which enter the Krebs cycle. a. As a part of normal fatty acid catabolism two acetyl CoA molecules can form acetoacetic acid, beta-hydroxybutyric acid and acetone. b. These three substances are known as ketone bodies and their formation is called ketogenesis. Ketones are water soluble and can cross the blood brain barrier to enter brain cells. Once there the ketone bodies can be converted back to acetylCoA and enter the Krebs cycle to make ATP. An excess of ketone bodies, called ketosis, may cause acidosis or abnormally low blood pH

protein anabolism

involves the formation of peptide bonds between amino acids to produce new proteins & is stimulated by human growth hormone, thyroxine, and insulin. 2. Of the 20 amino acids in your body, 10 are referred to as essential amino acids. These amino acids cannot be synthesized by the human body from molecules present within the body. They are synthesized by plants or bacteria. Food containing these amino acids are "essential" for human growth and must be a part of the diet.

fate of lipids

lipids may be oxidized to produce ATP, stored in adipose tissue, or used as structural molecules or to synthesize essential molecules

metabolism

refers to all the chemical reactions in the body

HDL

remove excess cholesterol from body cells and transport it to the liver for elimination. "good cholesterol"

reduction

the opposite of oxidation, that is, it is the addition of electrons to a molecule and results in an increase in the energy content of the molecule

oxidation

the removal of electrons from a molecule, results in a decrease in the energy content of that molecule. (it is energy releasing) Most biological oxidations involve the loss of hydrogen atoms. a) When a substance is oxidized, the liberated hydrogen atoms do not remain free in the cell but are transferred immediately by coenzymes to another compound. b) Two coenzymes commonly used to carry hydrogen atoms are NAD and FAD