Nutrition & Urinary System

  1. Metabolism
    the sum total of the chemical reactions of cells
  2. 6 types of nutrients
    • carbohydrate
    • fat
    • protein
    • vitamins
    • minerals
    • water
  3. Nutrient roles
    • roles in catabolism
    • roles in anabolism
    • roles in regulation of metabolism (anabolism + catabolism)
  4. Nutrient roles in catabolism
    • breakdown of nutrients for energy
    • carbohydrate-> sugars
    • fats-> fatty acids
    • protein-> amino acids
    • +alcohol
    • C, H, O part of molecule uses O2 to breakdown and form CO2+H20+ATP+heat
    • nitrogen in amino acid breakdown-->waste ammnonia (NH3) (only a little, the rest is converted into urea and uric acid- all 3 are excreted in urine)
  5. Nutrient roles in anabolism
    • anabolism: syntesis reactions
    • use the products of carb, fat and protein digestion for synthesis of compounds (either new protein carb or fat)
    • some minerals are used for synthesis- calcium for bone tissue, iron for hemaglobin, etc
  6. Nutrient roles in regulation of metabolism
    • vitamins and some minerals act as catalysts- stimulate rxns (many b vitamins stimulate processes)
    • water and minerals are important to provide the right environment for rxns to take place
    • water important in rxns (ex- catabolism- hydrolysis in the digestive system; required for synthesis of some molecules)
  7. Relationship between anabolism and catabolism
    in a healthy adult, there is a dynamic equilibrium and rate of anabolism= rate of catabolism
  8. Metabolic rate
    the speed of reactions, determines how many calories we need for each day
  9. Energy output
    amount of calories used in a day
  10. energy input
    • the amount of calories needed in our food
    • input should= output
  11. Total metabolic rate
    equal to the basal metabolic rate + skeletal muscle contraction + the small amount of involuntary movement
  12. Basal metabolic rate
    the lowest energy you need to live without eating, moving, etc
  13. what determines the energy needed for skeletal muscle contraction
    exercise and voluntary movement
  14. Small amount of involuntary movement is from...
    • shivering
    • food induced thermogenesis- the small amount of energy needed to digest food (5-10%)
  15. Factors affecting basal metabolic rate (things you cannot change)
    • Age
    • Growth
    • Sex of a person
    • Pregnancy
    • Body Shape and Surface Area
    • Hormones
    • Genetics
  16. Age (affecting basal metabolic rate)
    • the younger you are, the faster your metabolic rate is and it decreases as you get older
    • older ppl need fewer calories bc their metabolism is slower
  17. Growth (affecting basal metabolic rate)
    increases basal metabolic rate
  18. Pregnancy (affecting basal metabolic rate)
    • increases basal metabolic rate
    • lactation raises basal metabolic rate
  19. Sex of a person (affecting basal metabolic rate)
    on avg, males have a higher basal metabolic rate than females bc females have more subcutaneous fat (which has a slower metabolism than other tissue such as muscle)
  20. Body shape and surface area (affecting basal metabolic rate)
    • tall thin person has a faster metabolic rate than a short not thin person who weighs the same
    • increasing surface area (getting taller) makes it easier to release heat into the environment
  21. Hormones (affecting basal metabolic rate)
    • thyroid hormone stimulates metabolic rate of all cells
    • epinepherine increases metabolic rate in stress
  22. Energy balance
    • the calories in your food = the calories that you use
    • if this is true you maintain your body weight
    • if calories in food > calories used- weight gain
    • if calories in food < calories used- weight loss
    • Homeostasis would be staying around the same weight
  23. Regulation of food intake (eating)- brain
    • hypothalmus has arcuate nucleus
    • hypothalamus has 2 centers that release peptides
    • hypothalamus affected by part of the brain stem and signals from the GI tract, liver and hormones
  24. 2 centers of the hypothalmus for regulation of eating
    • 1. Feeding Center: increases appetite
    • ----> peptides- neuropeptide Y and agouti related peptide released to stimulate hunger
    • 2. Satiety Center: decreases appetite
    • ----> peptides- proopiomelanocortin decreases sense of hunger and supresses appetite
  25. How does the body's energy needs affect the hypothalamic centers?
    • blood glucose is the preferred energy source of the body, especially of the brain
    • if you havent eaten and blood glucose is low, feeding center stimulates your appetite
    • when you have eaten and food has been absorbed you increase blood glucose level stimulating the satiety center
  26. increased energy needs that will increase your hunger
    • exercising
    • growth states- child growth spurt, pregnancy, lactation etc (your body automatically tells you you need more)
  27. Hormones affecting blood glucose
    • Insulin
    • Glucagon
    • Growth Hormone, hydrocortisone, epinepherine
  28. Insulin
    • made in pancreas
    • decreases blood glucose- stimulates cells to take up glucose and break it down for energy
    • stimulates synthesis of glycogen to store glucose (polymer of glucose)
    • stimulated by an increase of blood glucose after you eat
  29. Glucagon
    • made in the pancreas
    • responds when there is low blood glucose (as in if you havent eaten) and increases blood glucose by stimulating break down of glycogen into glucose
  30. Gluconeogenesis
    • creation of glucose
    • convert amino acids or glycerol to glucose (liver is key in this)
  31. Growth Hormone, Hydrocortisone, Epinepherine
    • made in pituitary gland, and adrenal gland (last 2)
    • all increase blood glucose
  32. Hormone effect on eating
    • hormones have signals to decrease hunger
    • when a person has eaten and/or increase blood glucose 
    • they act by affecting the hypothalamus
  33. Hormones triggered from glucose level that act to decrease hunger
    • Insulin: makes cells take up glucose
    • Cholecystikinin: made in small intestine
    • PYY: made in small intestine
  34. Hormones triggered by fat level
    • Leptin: made in adipose tissue (fat is the main way we store energy so when you have significant fat stored you trigger leptin- important for storing fat energy long term)
    • decreases hunger
  35. Hormones that send signals to increase hunger when you're not eatin
    • Glucagon: made in pancreas
    • Epinepherine: made in adrenal gland
    • Ghrelin: made in stomach- helps trigger signal to eat from empty stomach
    • all of these increase blood glucose
  36. Body temperature and eating
    • when there is a lower body temp- stimulates eating
    • when you eat and breakdown nutrients you produce ATP and heat
    • Higher body temp- you eat less
  37. Temperature balance
    • Normal body temp: 37 deg. C- optimal temp for cell reactions
    • there is a daily rhythem in temp where it is lowest in the early morning hours and highest in the late afternoon/early evening (1 deg. C fluctuation)
  38. Increase in body temp  (affect on reactions)
    • speeds up reactions to a limit
    • ex: 1 deg C increase= 10% increase in speed, but cant get too hot or enzymes can be denatured
  39. Cold environment (effect on body temp reactions)
    • slows reactions
    • ex: in surgery they make the room cold for this
  40. Regulation of body temp (physiological and behavioral factors)
    • heat production
    • heat loss
  41. Heat production
    • we produce heat in metabolism 
    • basal metabolic rate: baseline
    • skeletal muscle activity: voluntary
    • eating
    • minor temperature effect
  42. Heat loss from the body
    • radiation: the blood vessels of the skin dilate and you release heat to the environment
    • conduction (not nervous): the transfer of heat directly to an object (ex- a necklace is cold when you first put it on, but it picks up your body heat)
    • convection: warm air rises and is replaced by cooler air
    • evaporation: water vapor loss from the body in sweating (water also evaporates from mouth and lungs)
  43. Heat regulation by the brain
    Hypothalamus has 2 thermoregulatory centers
  44. 2 thermoregulatory centers of the hypothalamus
    • Heat loss center
    • Heat promoting center
    • these both receive info from the external environment and in the hypothalamus which measure internal body temp (this info goes tot he hypothalaums centers and the hypothalamus then determines the autonomic nervous response if youre not in homeostatic range
  45. Brain regulation if body temp or external temp is too high
    • you want to increase heat loss and decrease heat production by inhibiting the heat promoting center and stimulating the heat loss center
    • dilation of skin blood vessels increases radiation, convection and conduciton
    • increased sweating (symp NS)
  46. Brain regulation if body temp or external temp is too low
    • you want to prevent heat loss and increase heat production
    • constrict the skin blood vessels to keep the heat internal and not lost to environment
    • insulation by subcutaneous fat prevents heat loss (malnourished ppl have harder time maintaining body temp)
    • shivering- triggered by heat promoting center
  47. frostbite
    if its extremely cold, you have so much constriction of blood vessels that you decrease O2 and nutrients to the cells in certain areas which can then die
  48. What special mechanisms do newborns have to stay warm
    • they can increase their metabolic rate by increasing hormones- epinepherine stimulated by symp NS and thyroid hormone stimulated by NS, both increase metabolic rate
    • brown fat: this tissue has the ability to make heat (controlled by symp NS)- non shivering thermogenesis
    • they can do all this because they do not have much subcutaneous fat, cant shiver and have poor center temp regulation
  49. Disorders of body temp balance
    • Hyperthermia
    • Hypothermia
  50. Hyperthermia
    • Fever
    • Febrile Seizure
    • Temp of > or = to 105 deg. F
  51. Fever
    • controlled hyperthermia (up to 104 deg. F)
    • part of the bodys defenses- the inc. temp speeds up defenses
    • chills: vaso constriction of the skin blood vessels to keep the warm blood internal for the fever to speed up rxns- even tho high temp you feel cold
  52. Febrile Seizure
    • about 7% of kids under 5 get it
    • if they spike a fever they can suddenly get convulsions- due to a depressed condition of the neurons where proteins start to be denatured
  53. Temp of 105 deg. F or more
    • not homeostasis- something has happened and hypothalamus cannot cope- exposure to high heat and heat production
    • heat stroke- can degrade visceral functions and be deadly
    • heat exhaustion- usually from extreme sweating and ppl have danger of being dehydrated causing a drop in bp and possibly mental confusion
  54. Hypothermia
    • decreased body temp/environmental temp
    • if you have exposure to cold it can cause a coma and death by cardiac arrest
    • cold slows enzyme activity affecting organs including heart, decreased resp. rate, heart rate and blood pressure til death
    • ppl can become drowsy and go from feeling cold to comfortable- they lose sensations as things start to shut down, shivering stops, youve reached max heat production
  55. Organization of Urinary organs (They make urine and excrete it)
    • kidneys
    • Ureters
    • Urinary bladder
    • Urithra
  56. Kidneys
    • 2 of them
    • make urine
  57. Ureters
    • 2 of them 
    • collect urine from kidneys and drain it to urinary bladder
  58. Urinary bladder
    stores urine and releases it to urethra
  59. Urethra
    • collects urine from bladder and excretes it to outside
    • in men- urethra also a passageway for semen leaving the body, but not at the same time
  60. Functions of the Kidney
    • Overall: Filter the blood and remove wastes from the blood while retaining key substances in the body
    • 1. Excretion of wastes
    • 2. Maintaining Homeostasis of the extracellular fluid of the body
    • 3. Endocrine Functions
    • 4. Metabolises Vitamin D to its active form
    • 5. Gluconeogenesis
  61. Excretion of wastes (kidney function)
    useless and harmful material that comes from the blood plasma excreted into the urine
  62. Wastes
    • metabolic wastes: produced in metabolism (ex- nitrogen waste from protein catabolism: urea, uric acid, NH3 and creatine)
    • foreign/toxic material
    • excess water and salts and other excess material
  63. Maintaining homeostasis of the extracellular fluid of the body (Kidney function)
    • composition, volume and pH are regulated by kidney
    • important in fluid and electrolyte balance and acid base balance
  64. Endocrine functions (Kidney function)
    make hormones such as erythropoeitin (stimulates RBC synthesis) and renin (acts as an enzyme, vital for blood pressure balance)
  65. Gluconeogenesis (Kidney function)
    in times of severe starvation it can do this, but it usually doesnt
  66. Kidney Structure- location
    Retroperitoneal location (behind the parietal peritoneum membrane)
  67. Internal kidney structure
    • cortex: outer area
    • medulla: inner area
    • nephrons
  68. Nephrons
    • microscopic structures in the kidney
    • structural and functional units of the kidney that make the urine
    • each nephron is made up of vascular elements (blood vessels) and tubular elements
  69. Vascular elements of the nephron
    • glomerulus
    • efferent and afferent arterioles
    • peritubular capillaries (lead to veins, come from efferent arteriole)
    • vasa recta- bvs surrounding henleys loop
  70. Tubular elements of the nephron
    • glomerular capsule
    • proximal convoluted tubule
    • henley's loop
    • distal convoluted tubule
    • collecting duct
  71. Steps of urine formation
    • 1. Glomerula filtration
    • 2. Tubular reabsorption
    • 3. Tubular secretion
  72. Glomerular filtration
    blood is filtered from the glomerulus into the glomerula capsule
  73. Filtrate
    • fluid in the glomerular capsule
    • contains a lot of water and all types of small solutes (nutrients and wastes), but nothing big like blood cells or protein (so this stuff isnt in urine either then)
    • very dilute and contains nutrients you dont want to lose (there has been no adjustment yet for water, electrolyte, acid-base, and blood pressure balance- still need tubular reabsorption for this)
  74. Tubular fluid
    • fluid in general in the tubules 
    • its only called urine after all the steps are over, filtrate or tubular fluid is NOT urine
  75. Tubular Reabsorption
    the movement of substances from the tubular fluid into the peritubular capillaries to retain in the blood what you do not want to excrete (ex nutrients)
  76. Tubular secretion
    • the movement of substances from blood to tubular fluid
    • substances you need to excrete that arent already in the tubular fluid (ex- acid)
  77. What happens as blood flows through the kidney
    urine forms and is collected in the renal pelvis and into the ureter
  78. Glomerular filtration (pressure)
    • pressure gradient is the driving force for the process
    • water and solutes flow from glomerulus to glomerular capsule
    • a fast process with a lot of water and the small solutes flow from the glomerulus into the glomerular capsule
    • there are 2 other pressures in the opposite direction (from glomerular capsule to glomerulus) but combined they are not as much as the main other pressure
  79. 2 other opposing pressures in glomerular filtration
    • 1. colloid osmotic pressure of the glomerular blood
    • 2. capsula hydrostatic pressure
    • Glomerular hydrostatic pressure is greater than both of these combined
  80. Speed of blood entering and leaving the glomerulus
    • blood enters faster than it leaves (this is why afferent arteriole is wider)
    • this creates the glomerula hydrostatic pressure (blood pressure) causing things to move into the glomerular capsule
  81. Colloid osmotic pressure
    • colloids: blood cells and proteins- stay in the blood b/c theyre too big to go in the capsule
    • attract H2O from the golmerular capsule into the blood of the glomerulus by osmosis
  82. Capsula hydrostatic pressure
    • the pressure of the physical fluid in the capsule pushin toward the glomerulus
    • nota lot of fluid builds up bc it flows through the rest of the tubules in the nephron making the pressure low
  83. Glomerular Filtration Rate
    • the volume of filtrate formed per minute in the kidneys
    • influenced by the blood pressure
    • kidney functioning critical in blood pressure homeostasis
  84. How much of water in the filtrate needs to be put back into the blood 
    where will it be absorbed
    • more than 97% 
    • will be absorbed in different parts of the tubules
    • it will be put back into the blood of the peritubular capillaries
  85. Why is tubular reabsorption critical?
    • needed for survival on land- allows body to conserve fluids
    • long henleys loop is good for this too
    • nature of your urine reflects how much water you drink
  86. Order of absorption in tubular reabsorption
    • 1. Proximal Convoluted Tubule
    • 2. Henley's Loop
    • 3. Distal Convoluted Tubule
  87. Proximal convoluted tubule (PCT)
    • closest to glomerulus
    • as the tubular fluid flows through the nephron, substances need to go back into the blood in surrounding blood vessels
    • here nutrients (and some salts and H2O) get reabsorbed back into blood
  88. How are nutrients (other than water, Na+ and Cl-) absorbed in the PCT
    • nutrients other than electrolytes and water: active transport- pumped back into the blood
    • Cations (Ca++, K+, Mg++): passive transport
    • urea waste: some reabsorbed by diffusion and secreted later on
  89. How are water, Na+ and Cl- absorbed in the PCT
    • Na+ pumped by active transport from the tubular fluid into the blood
    • the new + charge in the blood attracts CL- into the blood by diffusion, followed by water attracted by the solutes which goes in by osmosis
  90. Henley's loop importance
    • to reabsorb much more Na+, Cl- and water 
    • allows a LOT of reabsorption
    • long loop allows more conservation of H2O
    • has thin and thick segments, descending limb and ascending limb
  91. Henley's loop- descending limb
    permeable to water but not Na+ or Cl-
  92. Henley's loop- ascending limb
    allows Na+ and Cl- to leave the tubule, but isnt permeable to water
  93. Steps of nutrients and water leaving henley's loop
    • 1. Na+ is pumped by active transport from the thick segment of the ascending limb into interstitial fluid
    • 2. Cl- follows by diffusion into interstitial fluid from the thick seg. bc its attracted to the Na+
    • 3. The interstitial fluid is now salty and attracts water which comes from thin segment of descending limb by osmosis bc its permeable to water there
    • 4. Na+, Cl- and water in the interstitial fluid flow by diffusion into the surrounding blood vessels to be reabsorbed into the blood
  94. Countercurrent multiplier mechanism
    • allows for a lot of fluid to be absorbed
    • name indicates directions of flow of the tubular fluid and the blood
    • maximizes reabsorption as the tubular fluid flows through the nephron
    • effect multiplied over many nephrons maximizing absorption
  95. Distal Convoluted Tubule (DCT)
    has fine control of reabsorption- controlled by hormones that are released when needed
  96. Calcium reabsorption in the DCT
    • reabsorption from the tubular fluid in the DCT into the peritubular blood is stimulated by parathyroid hormone
    • this will increase blood Ca++ level when it starts to get low
  97. Water reabsorption in the DCT
    stimulated by antidiuretic hormone- prevents water excretion in the urine by stimulating the water in the DCT to go back into the blood
  98. Antidiuretic Hormone signaling water retention
    • ADH made in hypothalamus in the brain
    • hypothalamus senses a drop in H2O in the body and blood and it makes ADH which goes to the posterior pituitary gland and then into the blood
    • it also goes to the kidney to stimulate H2O reabsorption
  99. Sodium reabsorption
    • stimulated by aldosterone from the adrenal cortex
    • involves the renin-angiotensin system
    • important for blood pressure homeostasis- its triggered when there is a drop in blood pressure and the mechanism will increase it back to homeostasis
  100. aldosterone
    influences sodium balance, fluid balance, blood volume and blood pressure balance
  101. Regulation of blood pressure homeostasis by affecting blood volume
    • aldosterone and rening angiotensin system involved
    • Distal Convoluted Tubule: reabsorption of na+ and cl- then H20
    • the mechanism is stimulated when there is a drop in blood pressure--> we increase reabsorption of fluid to increase blood volume and blood pressure
    • result: we retain na+ cl- and H2O in the peritubular blood instead of excreting it all in the urine
  102. Juxta glomerula Apparatus (or complex)
    • an area of cells in the nephron near the glomerulus and the afferent arteriole
    • these cells sense blood pressure as a stimulus and will be triggered by a drop in bp (or low sodium in the blood)
    • response: make renin in the juxtaglomerular apparatus cells
  103. renin
    acts as an enzyme triggering angiotensin which triggers aldosterone (cascade effect)
  104. Process of increasing blood pressure when it is low
    • 1. Juxta glomerular apparatus (in kidney) stimulated by low bp
    • 2. JGA relases renin in the blood which stimulates conversation of Angiotensinogen to angiotensin I (both inactive)
    • 3. Angiotensin I converted to active angiotensin II by angiotensin converting enzyme
    • 4. Angiotensin II goes to adrenal cortex and stimulates secretion of aldosterone
    • 5. Aldosterone stimulates reabsorption of sodium from DCT into blood peritubular capillaries followed by Cl- reabosrtion followed by H2O reabsorption
    • 6. All of this water reabsorption increases blood volume which increases blood pressure
  105. Angiotensinogen
    • inactive plasma protein
    • already in the blood,  made in the liver
  106. Angiotensin converting enzyme
    present in the capillaries, converts angiotensin I to angiotensin II
  107. Antidiuretic hormone effect on increasing blood pressure
    once you start increasing Na+ and Cl-, the blood gets salty triggering ADH production and release which stimulates water reabsorption into the blood which helps increase blood volume and blood pressure
  108. How to treat high blood pressure by affecting volume
    • You want to decrease blood volume by increasing urination excretion of fluid
    • Medication: Angiotensin converting enzyme inhibitor, Lasix, Alcohol
  109. Angiotensin converting enzyme inhibitor
    prevents the action of the angiotensin converting enzyme so you  can't form angiotensinII which means no aldosterone so no reabsorption of Na or Cl or water so more water in urine than blood meaning lower blood volume
  110. Lasix
    a diuretic that inhibits h2o reabsorption in Henle's loop, which causes more water in urine than going into the blood decreasing blood volume
  111. Alcohol affect on blood volume
    a diuretic that inhibits ADH- meaning decreased H2O reabsorption and more water in the urine
  112. Untreated diabetes mellitus
    • low insulin and high blood glucose level but the cells can't take up glucose so it builds up in blood and ends up in the urine
    • High solute (glucose) excretion stimulates high H2O excretion because you have to dissolve the glucose --> pylori- a lot of urine, can be so much that it decreases blood volume and therefore blood pressure
  113. Tubular secretion
    the release of substances from the peritubular blood into the tubules of the nephron
  114. Tubular secretion substances
    • potassium: excreted (if theres excess)through active transport and ends up in urine
    • urea (that was previously reabsorbed): and uric acid secreted by passive transport
    • Acid: secreted- makes urine slightly acidic important for acid base balance (secreted as H+ directly or as Ammonium (H+ +NH3)
    • drugs
    • excess sodium and chloride and water
  115. Where is sodium level and high blood pressure measured?
    • right atrium of the heart
    • causes atrial natriuritic hormone to be released
  116. Atrial natriuritic hormone
    • stimulates Na+ secretion from the peritubular blood into the tubules of the distal convoluted tubule to go into the urine
    • this is followed by Cl- (bc of charge) and water (bc of solutes) lowering blood volume and therefore blood pressure
  117. Natriuresis
    excretion of sodium
  118. Kidney dialysis
    if you have renal failure (non functional kidneys), 2-3 times a week the blood has to be filtered through a machine
  119. What should you do if you have kidney disease?
    • blood pressure homeostasis is important especially for glomerular filtration
    • diet: avoid excess protein (breakdown makes Nitrogen waste which puts a burden on kidney function); avoid excess sodium to avoid high blood pressure
  120. What happens after the urine is made?
    • it leaves the kidneys by the renal pelvis and goes to the ureter
    • ureters transport urine to bladder
  121. What regulates the flow of urine to the bladder?
    • flow is regulated by the fact that the urine distends the ureter- the stretch from the urine is the main stimulus for flow and it stimulates peristalsis (wave like contraction) of ureter smooth muscle
    • there is also autonomic NS input
  122. Kidney Stones
    • renal calculi
    • crystals (made of Ca++, Mg++ uric acid, etc) that crystalize in the renal pelvis. They may get stuck in the ureter decreasing urine output (urination is blocked)
    • can pass on their own, but must be broken up if they dont
  123. Kidney stone treatment
    • shock wave lithotripsy: pulverizes the crystals, less invasive
    • surgery: more invasive
  124. Bladder
    like the stomach has ruggae folds that allow distention for storage of urine
  125. Detrusor muscle
    3 layers of smooth muscle
  126. 2 bladder sphincters
    • internal urethral sphincter: involuntary
    • external urethral sphincter: voluntary
  127. Urethra
    a thin smooth muscle tube, brings urine to the external environment
  128. Urethra length
    • women: shorter, 3-4 cm
    • men: 20 cm (longer bc runs the length of the penis)
  129. Urinary tract infection
    • usually bacterial 
    • bacteria enters urethra from external environment (sexual contact or fecal matter)
    • women more at risk, bc shorter urethra closer to outside of body
  130. Urinary Tract infection symptoms
    • disurea: painful urination
    • urinary urgency + frequent urination
    • sometimes fever
    • sometimes cloudy urine (from WBCs trying to fight infection)
    • maybe blood
  131. If the kidneys are involved in the UTI
    • there is often backpain
    • possible headache
    • not likely but possible
  132. Control of urination
    • when not urinating: sympathetic NS inhibits contraction of the detrusor muscle of the bladder
    • if theres about 200mL of urine in the bladder: stimulates urge to urinate- stretch receptors in the bladder are stimulated
    • If you reach 500-600 mL in bladder you lose voluntary control and urine is released
  133. Control of urination (brain)
    • if stretch receptors are stimulated and cerebral cortex is stimulate to make a decision to urinate, impulses go to the micturition center in the pons
    • this will have a parasympathetic response through a spinal nerve to contract the detrusor muscle of the bladder and open internal spincter and opening of external will be voluntary
  134. Another name for urination
  135. Fluid Balance
    • the fluid input into the body = the fluid output
    • total H2O volume in the body is kept homeostatic
  136. Fluid input
    • drinking liquid with water (regulated by thirst): 60%
    • eating food with water (fruits, veggies, some cheeses): 30%
    • water made in metabolism (breakdown nutrients such as glucose is converted to CO2+ H2O+ heat + ATP: 10%
  137. Fluid output
    • Urination (60%): most important factor in water regulation
    • Sweat (~8%): obvious water loss (seen)
    • Breathing (28%): insensable water loss (not noticed)
    • Feces (4%)
  138. How much water do you need per calorie a day?
    • Adults: 1mL per calorie (2000 calorie diet requires 2000mL of water)
    • Athletes: 1.5mL, more sweat loss
    • Infants: 1.5mL, faster metabolism and faster turnover (excretion) of water
  139. Where is the thirst center?
  140. thirst stimulus
    • a change in the osmolarity of the blood (an increase of 2-3%- increased salt, decreased H2O or both)
    • less h2o causes less saliva causing dry mouth and increasing sensation of thirst (possible to have dry mouth without change in osmolarity)
    • increased blood loss (hemmorhaging): can trigger thirst
    • diabetes: frequent urination increases thrist
    • increased need for fluid in the body: such as in lactation
  141. What happens when you start drinking
    • when you moisten the mouth and throat this decreases your thirst before you decrease the osmolarity of the blood
    • increased fluid in stomach and small intestine after drinking stimulates stretch receptors and decreases thirst by inhibiting thirst center (protects against drinking too much @ once)
  142. Disorders of H2O balance
    • Dehydration
    • Diabetes Insipidous
    • Hypotonic Hydration
    • Edema
  143. Dehydration
    • fluid output> fluid input
    • can happen by increase of H2O loss (vommiting, sweating, blood loss, diarrhea, excess urination, polyurea in diabetes)
    • can happen by decreased water intake
  144. Diabetes insipidous
    • a low level of antidiuretic hormone 
    • very rare
    • decreased H20 reabsorption back into the blood so increased water in urine
  145. Symptoms of dehydration
    • increased thirst (unless increased urination is the cause decreased urination will occur because there is less H2O in the body)
    • long term: fever, mental confusion, low blood volume causing hypovolemic shock (very low blood pressure), death is possible
  146. Hypotonic hydration
    • over hydration
    • a very high amount of H2O intake in a short time period, especially if the person doesn't urinate
    • happens after intense exercise
    • you have too much water and the blood is too dilute causing hyponatrimia (low Na+ concentration in extracellular fluid) causing edema (swelling)
  147. symptoms of hypotonic hydration
    nausea, vommitting, muscle cramps, cerebral edema, convulsions, coma, possible death
  148. Edema
    • accumulation of fluid in the interstitial spaces of the tissues
    • causes: high H2O intake in short time period without excretion; too little protein in blood vs the water; kidney or liver disease
  149. Homeostatic range of blood pH
    • 7.35 (deoxygenated)- 7.45 (oxygenated)
    • pH within cells is 7.0
  150. What happens if blood in systemic arteries is less than 7.35 or more than 7.45
    • if under 7.35 there is blood acidosis/acidemia- too much acid in the blood
    • if over 7.45 there is alkalosis or alkalemis- blood is too basic
    • if pH is less than 7 or more than 7.8 you die
  151. 3 mechanisms maintaining acid base balance
    • Respiration
    • Kidneys
    • Buffers
  152. Respiration (maintaining acid base balance)
    • CO2+ H2O= carbonic acid which breaks into hydrogen ion and bicarbonate
    • more CO2= more acid
    • if too much acid, we want to rid blood of CO2- exhaling does this
    • pH of blood measured by medulla 
    • if pH is too low (arteriole blood is less than 7.38)this triggers an increase in the rate and depth of breathing to rid the CO2 and decrease acid formation
    • when pH increases, respiration decreases
  153. Kidneys (maintaining acid base balance)
    urine is the only way we get H+ out of the body (we rid the body of excess H+ or NH4 by tubular secretion)
  154. Kidneys- ridding the body of acid by na+ absorption
    • if you reabsorb Na+ from the tubular fluid into the blood, when you secrete h+ ion youre replaceing H+ ion in the blood with an Na+ ion (salt replaces acid)
    • when the body reabsorbs na this will increase HCO3- reabsorption in the blood (acts like Cl- and follows na) causing increase in salt in blood 
    • if there is direct reabsorption of HCO3- into the blood na+ will follow
    • if we have high HCO3- excretion in the urine, there will be increased Na+ excretion to follow meaning less salt in blood- a way to decrease pH of blood bc less salt means more H+ ions
  155. Why is HCO3- important
    • it is an important buffer in the blood
    • salt (NaHCO3-) acts as a weak base
  156. Buffers (maintaining acid base balance)
    • buffers prevent large changes in pH in the blood
    • there are buffers in cells, outside of cells, in blood
    • buffers come in pairs: if you have a strong acid entering the body you will try to neutralize it by replacing it with a weak acid (strong base entering you want to replace it with a weak base)
    • There are 3 major buffer systems in the body
  157. 3 buffer systems of the body
    • 1. Bicarbonate Buffers
    • 2. Phosphate Buffers
    • 3. Protein Buffers
  158. Bicarbonate buffers
    • pair is carbonic acid and sodium bicarbonate
    • in cells but xtra important in extracellular fluid of tissues
    • when a strong acid enters: reacts with salt
    • when a strong base enters: reacts with weak acid
  159. Bicarbonate buffers (examples)
    • 1. strong entering acid:HCl
    • reacts with sodium bicarbonate (salt- acts as a weak base)
    • forms NaCl + carbonic acid (weak acid)
    • 2. strong entering base: NaOH
    • reacts with weak acid (carbonic acid)
    • forms H20 and NaHCO3 (salt-weak base)
  160. Phosphate buffers
    • important in cells and in the urine (decreases acidity of strong acids that end up in urine)
    • not important in blood plasma
    • weak acid: NaH2PO4
    • salt: Na2HPO4
  161. Protein buffers
    • many proteins can be buffers including plasma proteins and body cell proteins in general
    • the most important buffers in cells (more than phosphate buffers)
    • theres a protein in acid form and a protein in salt form
  162. protein buffer example
    hemaglobin in RBCs can be a buffer
  163. example of acid in the body that needs to be neutralized
    HCl from stomach- bicarbonate from pancreas acts on the HCl that ends up in the small intestine to neutralize it
  164. Ketosis
    • increased ketones (acidic) produced from fat breakdown
    • happens in untreated diabetes mellatus
  165. Acid base balance disorders
    • Acidosis: too much acid in blood
    • Alkalosis: too much base in blood
  166. Acidosis Disorders
    • respiratory acidosis
    • metabolic acidosis
  167. Respiratory acidosis
    • CO2 in the blood forms carbonic acid
    • Hypoventilation: you are not exhaling enough CO2 and you're therefore increasing carbonic acid in blood
    • this happens in emphsema
  168. Metabolic acidosis
    • Happens in...
    • Untreated Diabetes mellatus
    • Starvation
    • Severe Diarrhea 
    • Kidney disease
  169. Untreated Diabetes mellatus
    • you cant get glucose into cells and you break down fatty acids for energy, but to do this they are first converted to ketones and these acidic ketones form faster than theyre broken down
    • buffers try to neutralize ketones and kidneys try to excrete them, but there are too many and blood becomes acidic
  170. Starvation
    • you breakdown fat for energy giving you ketones
    • once fat runs out you break down protein (including muscle protein) and amino acids from protein form ketoacids for energy creating blood acidosis
  171. Severe diarrhea
    bicarbonate enters intestine from pancreas to neutralize stomach acid, but in severe diarrhea you can flush out the bicarbonate with feces and this loss of base leaves the blood and body too acidic
  172. Kidney disease
    we dont excrete enough acid in urine, keeping too much acid in the blood
  173. Alkalosis
    • respiratory alkalosis
    • metabolic alkalosis
  174. Respiratory alkalosis
    • too low CO2 in blood, decreased carbonic acid in blood making it too basic
    • hyperventilation causes this: increases CO2 loss
    • Hypoxia- low availability of O2 (at high altitudes): can lead to alkalosis bc you cant make the CO2 in cells without o2 so your losing CO2 exhaling and not making new CO2
  175. Metabolic Alkalosis
    • caused by high acid loss from the body or an increased base entering body
    • Vommitting: HCl from stomach lost, decreasing acid in blood bc acid leave blood to replenish it in stomach
    • Loss of acid in urine: ex- use of diuretics- lose H+ and h20 when increasing urine production
    • consuming antacids to neutralize stomach acid (ex Na Bicarbonate): main way bases enter body, you would need to take a lot
  176. More disorders of the Urinary system
    • Urethritis: inflammation of the urethra
    • Cystitis: inflammation of the bladder
    • Pyelitis or Pyelonephritis: Kidney inflammation
Card Set
Nutrition & Urinary System
Quiz of 3/20