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50 Cards in this Set

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Apart from ATP, what molecule, abundant in the muscle, holds energy in high energy phosphate bonds? What is the major difference between the two as regards their use of energy? Describe the interaction between ATP and this other high energy molecule.
Phosphocreatine. Phosphocreatine STORES/ATP TRANSFERS. They are in reverse equilibrium with each other, in favor of ATP (balance - too much ATP, make phosphocreatine)
Most of the energy in the body is eventually expelled as heat. This is an important principle in the study of metabolism. Define calorie.
Quantity of heat required to raise temperature of 1 gram of water by 1 degree celcius.
What is the average basal metabolic rate of a human? State the basal conditions that should be met in order to measure basal metabolic rate.
70 Calories/Hour.
Condition: no food for more than 12 hours, night of restful sleep, no strenuous exercise since sleep, more than 30 minute complete rest, 68-80 degree F in surrounding environment, no factors that excite
What is the principle of indirect calorimetry, and how can this principle be used to measure metabolic rate? Give examples of how metabolic rate can be altered, briefly describing how in each case.
Measures rates of oxygen utilization (in metabolism) bc 95% enegery expended in body is derived from aerobic metabolism.
Exercise: sleeping, eating, walking
Thyroid Hormone: maximal secretion, loss of secretion
Sympathetic Stim: maximal stim 15% incr in adult, 100% incr in newborn (need to generate heat to maintain body temp)
What is the normal temperature range of a person? When is a person in heat balance? What role does the hypothalamus have in maintaining body temperature?
98.6 (oral)
Heat balance - no change in body temperature (doesn't have to be normal).
Control center
Name the methods of heat loss from the skin and give a brief explanation of each, including the relative contribution of each to overall heat loss from the body.
Radiation: 60% when temperature different between two objects
Conduction: 3% contact of two objects (heat loss skin to air)
COnvection: 12% conducts heat through movement of air or water
Evaporation: 22%
Insensible (not controlled) or Sweating (when heat must be lost from body)
Describe the temperature receptors in i) the hypothalamus, ii) skin and iii) spinal cord and abdomen. Where are the signals from temperature receptors integrated?.
Hypothalamus: heat sensitive neurons in the preoptic area. MOST IMPORTANT
Skin: detects hot and cold (4-10x # cold vs hot sensors)
Spinal Cord/Abdomen: mainly transmit cold signals to CNS
INTEGRATED in hypothalamus
The body is effective in minimizing heat loss and increasing heat production when cold. Give examples of each and a brief explanation of how they work. How would a person whose spinal cord had been cut above the level at which sympathetic nerves leave the cord normalize their body temperature if they were cold?
Heat Conservation:
-vasoconstriction in skin
-piloerection
-abolition of sweating
Heat Production:
-shivering
-chmical thermogenesis(no ATP)
-increased thyroxine output to increase metabolic rate (all energy = heat)
Describe what happens to the body under cold temperatures of 94 °F, 85 °F and 77 °F.
94: normal response by conserving and producing more heat
85: ability to respond is compromised bc of low temperature
77: heart pumping decreased, control center shuts down, acceleration of body temp occurs, death results due to heart standstill or fibrillation
Describe the sweat gland and its formation of sweat. As a person becomes acclimatized to high temperatures, does their sweat production increase or decrease? What about their sodium/salt loss? How this is controlled by aldosterone.
Gland is like kidney nephron-conservation of salt.
Sweat production increases, sodium/salt loss decreases. Acclimitization causes increased aldosterone release.
Aldosterone increases active reabsorption of sodium by duct.
Explain, with the use of a diagram, the febrile condition of a person who has been subjected to a pyrogen. Discuss the changes in body temperature in relation to the set-point of the hypothalamic thermostat, describing the main stages of the condition and how the presence of the pyrogen plays a role.
1. Pyrogen: increase set point of hypothalamic thermostat
2. Chill: body produces and preserves heat to increase temp to new set point.
3.Plateau: body reaches new set point
4. Crisis: pyrogens leave, and body returns to normal set point, so body thinks it hot, and temp. decreases through sweating and vasodilation.
Heat stroke occurs when the body temperature reaches 106-108 °F. Why does this not occur at lower temperatures? How does humidity effect the body temperature? What leads to heat stroke and what are the symptoms? How should a person with heat stroke be treated? Heat stroke can be fatal. Describe the tissue damage that can be caused by hyperpyrexia. Name a common antipyretic. What is its principle function in relation to temperature regulation?
-At lower temp, control center still responds normally
-Incr. humidity, can't sweat to dissipate heat.
-dizziness, abdominal distress, delirium, loss of consciousness
-Ice water to lower body temp
-neurons damaged, less heat controol, tissue damage in brain
-Aspirin common antipyretic (removes pyrogens)
What is the average physiologically available energy in calories per gram of carbohydrate, fat and protein? What is the advised minimum daily intake of protein in an average man? What are complete and partial proteins?
Carb - 4, protein - 4, fat - 9
Atleast 30g protein
Complete more beneficial than partial - provide essential amino acids.
Define respiratory quotient. Using this, how can you estimate the relative quantities of fat and carbohydrate being metabolized? If the respiratory quotient is 0.85, what is the balance of fat to carbohydrate utilization?
RQ= % of food metabolized (ratio of co2 output to o2 usage as molecule oxidized)
1 = all carbs
0.7 = mainly fat
.85 = fat an carb
Energy regulation of feeding is controlled by the nutritional status of the body. Explain how blood glucose, amino acid and lipid concentrations are involved in this long-term energy regulation.
When the availability of any of three major groups is decreased, the desire for feeding is increased, evenutally returning blodd metabolite concenetrations back toward normal.
Explain the importance of having short-term and long-term regulation of feeding and how they compliment each other.
Long term helps maintain constant stores of nutrients in tissues, preventing them from becoming too low or high. Short term: 1) make person eat smaller quantities at each eating session and 2) keep person from eating amounts at meal that are too much for metabolic food storage.
Focusing on energy input versus energy output, describe the development and maintenance of obesity.
Obesity = energy input > energy output
To maintain, can still be balanced.
There are many factors that may contribute to obesity i.e., psychogenic obesity, genetic factors and childhood overnutrition. Briefly explain the contribution of each of these factors to obesity.
psychogenic: from lifetime habits
genetic factors:
a. abnormality of neurogenic feeding centers
b. abnormal heredity psychic factors
c. abnormal chemistry of fat storage
Chilhood: creates excessive fat cells
During starvation there is a gradual depletion of the energy stores in the body. With the use of a diagram, outline the utilization of carbohydrates, fats and proteins during the process of starvation.
Carbs are initial energy source - worth 1/2 day energy supply.
Fats/Proteins - fats 100x energy of carbs/3 stages protein depletion(rapid, slow, rapid)
Apart from ATP, what molecule, abundant in the muscle, holds energy in high energy phosphate bonds? What is the major difference between the two as regards their use of energy? Describe the interaction between ATP and this other high energy molecule.
Phosphocreatine. Phosphocreatine STORES/ATP TRANSFERS. They are in reverse equilibrium with each other, in favor of ATP (balance - too much ATP, make phosphocreatine)
Most of the energy in the body is eventually expelled as heat. This is an important principle in the study of metabolism. Define calorie.
Quantity of heat required to raise temperature of 1 gram of water by 1 degree celcius.
What is the average basal metabolic rate of a human? State the basal conditions that should be met in order to measure basal metabolic rate.
70 Calories/Hour.
Condition: no food for more than 12 hours, night of restful sleep, no strenuous exercise since sleep, more than 30 minute complete rest, 68-80 degree F in surrounding environment, no factors that excite
What is the principle of indirect calorimetry, and how can this principle be used to measure metabolic rate? Give examples of how metabolic rate can be altered, briefly describing how in each case.
Measures rates of oxygen utilization (in metabolism) bc 95% enegery expended in body is derived from aerobic metabolism.
Exercise: sleeping, eating, walking
Thyroid Hormone: maximal secretion, loss of secretion
Sympathetic Stim: maximal stim 15% incr in adult, 100% incr in newborn (need to generate heat to maintain body temp)
What is the normal temperature range of a person? When is a person in heat balance? What role does the hypothalamus have in maintaining body temperature?
98.6 (oral)
Heat balance - no change in body temperature (doesn't have to be normal).
Control center
Name the methods of heat loss from the skin and give a brief explanation of each, including the relative contribution of each to overall heat loss from the body.
Radiation: 60% when temperature different between two objects
Conduction: 3% contact of two objects (heat loss skin to air)
COnvection: 12% conducts heat through movement of air or water
Evaporation: 22%
Insensible (not controlled) or Sweating (when heat must be lost from body)
Describe the temperature receptors in i) the hypothalamus, ii) skin and iii) spinal cord and abdomen. Where are the signals from temperature receptors integrated?.
Hypothalamus: heat sensitive neurons in the preoptic area. MOST IMPORTANT
Skin: detects hot and cold (4-10x # cold vs hot sensors)
Spinal Cord/Abdomen: mainly transmit cold signals to CNS
INTEGRATED in hypothalamus
The body is effective in minimizing heat loss and increasing heat production when cold. Give examples of each and a brief explanation of how they work. How would a person whose spinal cord had been cut above the level at which sympathetic nerves leave the cord normalize their body temperature if they were cold?
Heat Conservation:
-vasoconstriction in skin
-piloerection
-abolition of sweating
Heat Production:
-shivering
-chmical thermogenesis(no ATP)
-increased thyroxine output to increase metabolic rate (all energy = heat)
Describe what happens to the body under cold temperatures of 94 °F, 85 °F and 77 °F.
94: normal response by conserving and producing more heat
85: ability to respond is compromised bc of low temperature
77: heart pumping decreased, control center shuts down, acceleration of body temp occurs, death results due to heart standstill or fibrillation
Describe the sweat gland and its formation of sweat. As a person becomes acclimatized to high temperatures, does their sweat production increase or decrease? What about their sodium/salt loss? How this is controlled by aldosterone.
Gland is like kidney nephron-conservation of salt.
Sweat production increases, sodium/salt loss decreases. Acclimitization causes increased aldosterone release.
Aldosterone increases active reabsorption of sodium by duct.
What is the function of ATP? Identify the feature that enables this function.
Energy TRANSFER --> high energy phosphate bonds
What is the normal blood glucose concentration of a person three to four hours after a meal? In order to be used by cells, glucose must first get into the cell. Name the pancreatic hormone involved in glucose transport into most cells. By what mechanism of transport does glucose move across cell membranes? In order to capture glucose inside the cell, what is it converted into?
0.9 mg/ml 3-4 hours after meal
<1.4 mg/ml after meal
Insulin activates glucose transport into cell.
-Faciliated Transport
-Glucose-6-phosphate
In order to store glucose it is converted into glycogen. This occurs primarily in the liver and muscle. Describe how this occurs (glycogenesis) and how glycogen is broken back down for energy (glycogenolysis).
Glycogenesis is formation of glycogen from glucose-6-phosphate.
Glycogenolysis is breakdown of glycogen to form glucose-6-phosphate.
Release of glucose from stores occurs when its needed elsewhere in the body. This begins pathway involving glycolysis, the Krebs cycle, and chemiosmotic mechanism/electron transport chain. Give outline of the steps under a)aerobic conditions and b)anaerobic conditions - how and where energy in the form of the ATP is released. Identify which step produces the majority of the ATP. What is rate-limiting step in the formation of ATP?
Kreb Cycle - degradation of acetyl coA into CO2 and hyrdogen atoms (small amt ATP)
Oxidative PHosphorylation - hydrogen atom ionized, releasing electrons.
Electrons move through ETC, and generated energy pumpeds H ions out of matrix. They flow back in through ATP synthetase, providing energy to form ATP.
ANAEROBIC - glucose-->pyruvic acid-->lactic acid. When oxygen replenished, lactic acid can convert back to glucose.
-Oxidative Phosh (28 ATP)
-Amount of glucose and O2; amount of ADP/ATP is ground control point
Apart from energy in the form of ATP and storage as glycogen, what is the other major byproduct of the breakdown of glucose?
PPP generates energy for conversion of carbs to FAT or TRIGLYCERIDES.
Define gluconeogenesis. Which, if any, of the following can participate in gluconeogenesis: carbohydrates, amino acids and fat.
Making of new glucose from triglycerides (glycerol) and amino acids.
-Amino Acids and Fats
Name the main types of lipids. Give the primary uses for lipids in the body.
Triglycerides, phospholipids, cholesterol. Used for energy storage, cell components and temp. regulation
State the important functions of the liver in the metabolism of lipids?
Degrades fatty acids into small compounds for energy.
Synthesizes triglycerides from carbs and some proteins.
Synthesizes other lipids from FAs (cholesterol and phospholipids)
Fats are absorbed from the gut and stored in adipose tissue as triglycerides. What is the basic structure of a triglyceride? Describe the pathway by which fat is stored, from chylomicron to triglycerides, paying particular attention to how fat enters the adipocytes.
-Glycerol and three fatty acids
-chilomicrons are a form of lipoproteins. The triglyceride must be split by lipoprotein lipase to enter the cell. Fatty acid can freely difuse into cell after broken then its recombined with glycerides in the cell to form triglycerides again.
Carbohydrates, in excess of what is used immediately and what is stored as glycogen, can be stored as triglycerides in adipose tissue. Describe the primary pathway by which this takes place. Give the advantages of storing energy as fat rather than as glycogen.
-Carbs can be stored as triglycerides. It occurs through reverse beta-oxidation. The advantage of storing it as triglycerides is that fat can store more energy than carbs.
Triglycerides are broken down and fatty acids allowed out of the cells into the blood. What is the stimulus for this and how are the fatty acids transported around the body?
-It is stimulated by a decrease in blood glucose.
-Triglyceride are broken down by intercellular lipase.
-Transported in the blood by albumins.
What is ketogenesis and give an example of a keto acid involved in the transport of fat degradation products from the liver to the peripheral tissues. Explain the pathway by which ATP can be extracted from fatty acids for use in normal body function. In what organ do the first steps occur and in what compartment of the cells?
-Ketogenesis is the conversion of amino acids to keto acid or fatty acid products.
-Example is acetyl acid which is two Acetyl-coA's.
-Pathway: FA are degraded by beta oxidation mainly in the mitochondria of the liver.
Identify the hormones involved in the regulation of fat utilization and define each of their roles.
Exercise: Epinephrine and Norepinephrine
Stress: Corticotropin --> glucocorticoids (mainly cortisol)
Growth Hormone...all of above cause release of hormone sensitive triglyceride lipase (fat cells) whihc then cause triglyceride breakdown and fat mobilization.
Thyroid hormone increases metabolism causing an increase in triglyceride breakdown and fat mobilization.
What are lipoproteins? Identify the types of lipoproteins describing their distinguishing feature(s). Where are they formed? What is their function?
-Lipoproteins are proteins that carry lipids in the blood.
-Most of the constituents are formed in the liver.
-The types: chilomicrons, BLDL, HDL, LDL.
-Their features: The amounts of triglycerides, phospholipds, cholesterol and proteins.
Phospholipids and cholesterol are carried around the body by lipoproteins. What is their primary, common function?
They are components of the cell membrane
What part of the vascular tree is the main target of atherosclerosis? What type of lipoprotein promotes and what type protects against atherosclerosis? Describe an atherosclerotic plaque, and why it may cause death. Explain why a hereditary deficiency of the LDL receptor may cause severe atherosclerosis.
-Main target are arteries.
-LDL
-The plaque is cholestol deposited by LDL which is then calcified. Pieces can break of resulting in thrombosis or a rupture because the arteries are less elastic. Causing death.
-Hereditary deficiency is that there are no LDL receptors so they can't be taken back so the LDL's stay in the blood depositing cholesterol in the arteries.
Define essential amino acid and give examples.
-Essential AA's are not made in the body. Lysine and Argenine are examples of essential AA's.
How are amino acids stored in cells and how are they released from cells if needed?
-They are stored as proteins.
-They are degraded in the liver by deamination removing the amino group to form keto acids. Those are oxidized to form substances for the Krebs cycle.
Name the key plasma proteins and state their primary function. What is their primary site of synthesis, and how are they regulated? How can plasma proteins be used in tissues if needed?
-Primary plasma proteins are albumin and globulin.
-primary function: Albumin prevents edema. Globulin has immunological functions.
-They are synthesized in the liver.
-They are regulated by the proteins available.
-They can be broken down to make AA's if they are needed by tissues.
Give examples of fibrous proteins and state their primary functions.
-Collagen.
-Function: Collagen is a major component of the extracellular matrix that supports most tissues and gives cells structure from the outside. Also found inside some cells.
Describe the process of energy extraction from proteins, including deamination, urea formation, and oxidation of keto acid products. What is the obligatory loss of proteins? How much protein should be ingested per day to balance this?
-Deammination occurs in the liver to yield keto acid or fatty acid. These products are oxidized by conversion into a substance that can enter the Krebs Cycle to yield ATP.... Ammonia is released during deamination is it is converted to urea in the liver and excreted.
-O.L. is the amount of protein lost each day no matter what... A person should ingest 20-30 grams of protein each day.