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pathophyiology
chapters 1-3
95
Physiology
Undergraduate 3
05/29/2009

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Term
What is the resting membrane potential
Definition
The difference between charges inside the cell and outside the cell.
Term
Threshold potential
Definition
This is the value reached when the cell will continue to depolarize with no further stimulation.
Term
Action potential
Definition
The rapid change that occurs when a nerve or muscle cell recieve a stimulus that exceeds the membrane threshold value
Term
Depolarization
Definition
When the membrane potential moves foward from a neg value to 0
Term
Repolarization
Definition
When the negative polarity of the resting potential is reestablished
Term
Absolute refractory period
Definition
When the plasma membrane can not respond to additional stimulation
Term
relative refractory period
Definition
Time when the permeability to K increases, a stronger than normal stimulus can cause a action potential
Term
Osmolality
Definition
measure of number of milliosmoles per kg of water or the concentration fo molecules per wt of water
Term
osmolarity
Definition
number of milliosmoles per liter of solution or concentration of molecules per vol of solution
Term
What is an isotonic solution and give examples
Definition
The same osmolality of particles as ICF and ECF, 5%dextrose in water, .09%nacl-
Term
What hypotonic solution and give example
Definition
It has a lower concentration and is more dilute than our body fluid, water
Term
What is an hypertonic solution
Definition
It has a higher concentration than our body fluids, 3% saline solution
Term
What is mediated transport
Definition

1. involves transport P

2. Has channels that require a protein transporter that creates a water filled channel so sp. ions can diffuse through the cell membrane

Term
Passive Transport
Definition

Does not require energy

movement of water down a concentration gradient

movement of water and solutes through a membrane because of increase pressure on one side of the membrane

movement of water from an area of greater solute concentration to area of lesser solute concentration

Term
Active Transport
Definition

Does require energy

Na K pump

Protein transporter moves molecules up the concentration gradient

plasma membrane enfolds substances on one side of the membrane and invaginates them

Term
How are body fluid classified
Definition

Intracellular

Extracellular

intersitital

intravascular

Term
Volume of total body water.  What are the reasons for variances
Definition
The is in porportion to fat the more fat the less water.  In infants tbw is75-80 after one year is is 67%.  In adulthood women have less water than men because they have more fat.  In the erlderly water decreases because of decrease in muscle and increase in fat, and reduce ability to regulate sodium and water balance.  The kidneys wear out and have a hard time maintaining water and na balance.
Term
Net filtration
Definition
the forces favoring filtration minus the forces opposing filtration, movement of fluid back and forth across the capillary wall.
Term
Hydrostatic pressure and oncotic and osmotic pressure have what effect
Definition
Hydrostatic has pushing effect verses osmotic pressure has a pulling effect
Term
Intracelular fluid
Definition
two thirds of the body's water
Term
extracellular fluid
Definition
1/3rd of the body's water
Term
intravascular fluid
Definition
blood
Term
what is edema
Definition
an accumulation of fluid in the interstital spaces.  The prov of fluid distribution and doesn't mean there is an excess of fluid
Term
what is the pathophysiology behind edema
Definition
an increase in hydrostatic pressure can result from venous obstruction or salt and water retention
Term
what are the clinical manifestations of edema
Definition
weight gain, swelling, tight-fitting shoes
Term
what are some disease processes that cause edema
Definition
chf, malnutrition, stroke post, cirrhorois of liver
Term
Hypertonic
Definition
Imbalances that result in an ecf concentration > than .9% sale solution  example hypernatrenia
Term
hypernatremia
Definition

When na levels > 145 intercelluar dehydration

causes decreased fluid intake

too much hypertonic saline sol such as sodium bicarb

too much aldosterone

cushing syndrome

too much acth

Term
What are the s/s of hypernatremia
Definition

thirst, dry mouth, low b/p, restlessness

serious- convulsions, pulmonary edema

Term
what is the treatment for hypernatremia
Definition
give isotonic salt free fluid such as 5% dextrose in water untill the serum level returns to normal
Term
Hyperchloremia
Definition
Occurs when there is and excess of sodium and deficit of bicarb
Term
Hypotonic alterations
Definition
when osmolality of ECF is less than norm.
Term
What is the most common cause of hypertonic alterations
Definition
not enough sodium or free water excess
Term
What is the pathophysiology of hyponatremia
Definition
When na level drops below 135 the decrease causes m.m. of water in the cell and cell swelling.
Term
What are the most common causes of hyponatremia
Definition
use of diuretis, vomiting, loose stools, gi suction, and burns
Term
Interstitual hydrostatic pressure
Definition
outward push of the intersitiual fluids against the outside of the capillary walls.
Term
Increases in hydrostatic pressure
Definition
will cause edema
Term
Increase in capillary permeability
Definition
decrease in plasma osmotic pressure
Term
capillary hydrostatic pressure
Definition
refers to the pushing outward of fluid against the capillary wall
Term
potassium concentration is ECF
Definition
3.5-4.5mEq/L
Term
How is the concentration of K regulated
Definition
Through the na k pump active transport system
Term
Why is K important
Definition
regulation of icf osmolality, glycogen deposition, maintains resting membrane potential
Term
What organ mostly controls the amount of K
Definition
Kidneys
Term
What in the kidneys filters K and where is it reabsorbed
Definition
It is filtered by the glomerulus and reabsorbed by the proximal tubule and loop of henle
Term
What system is set up to conserve K loss
Definition
protein tyrosine kinaase dependent signal transduction pathway
Term
What regulates water in the kidney
Definition
ADH
Term
Where does ADH come from
Definition
synthesised by cells in the hypothalamus
Term
When is ADH released
Definition
When osmoreceptors in the hypothalamus since changes greater or = to 1%, or baroreceptors sensitive to changes in the central bl. vol of > 5%
Term
What determines the the concentration of K in the distal tubular cell
Definition
plasma concentration in the peritubular capillaries
Term
What happens to K when s/o is taking diuretics
Definition
the rate of filtrate flow through the distal tubule will be higher and K will be excreted because the amount of K will be lower more will be excreted
Term
How do changes in ph and h ion concentration affect K balance
Definition
H ions move from ecf to icf during acidosis and k shifts out of the cell into the ecf this decrease results in decrease secretion of k into the urine by the distal tubular cells causing hyperkalemia.  In contrast with alkalosis K shifts into the cell so the distal tubular cells increase their secretion of K into the urine causing hypokalemia.
Term
How does aldosterone play a part in K regulation
Definition
When k concentrate is increased, aldosterone is released, stimulating secretion of K into the urine by distal tubules of the kidney.  it also increases the secretion of K from the sweat glands.
Term
How does insulin contribute to the regulation of plasma K levels
Definition
by stimulating the na, k atpase pump and promoting the movement of k into the cell of the liver and muscle cells.  I tcan be used to treat hyperkalemia and cause low levels of bl k.
Term
How do catecholamines influence K
Definition
Beta 2 receptors adrenergics stimulate the movement of K into the cells and a adrenergics shift K out of cells.
Term
What is K adaptation
Definition
The body is able to safely excrete K as long as the dose is no more than 120mEq per day
Term
how is resp alk corrected
Definition
h is pulled into ecf pco is decreased renal restores ph by < H excretion and bicard absorb
Term
What is hypokalemia
Definition
When serum potassium concentration less than 3.5, I alkalosis K shifts in to the cell in exchange for H to maintain plasma acid base balance.   It may be normal or elevated when total k is depleted when K shifts ifrom the ICF to the ECF.
Term
What is the Disease process that causes K levels to present as normal when total body K levels are depleted.
Definition
Diabetic ketoacidosis which the increae in H concentration causes to shift into the cell in exchange for K.  A normal level of K is maintained in the plasma but K continues to be depleted in the urine.
Term
What are some factors that cause hypokalemia
Definition
reduced intake of K, increased ento of k into cells, and increase losses of body K. diet deficit such as elderly with low P intake and inot enough fruits and veg, Alcholism or anorexia nervosa.
Term
What are some medications that cause hypokalemia
Definition
amphotericin b, gentamicin, and carbenicillin
Term
What are some of the clinical manifestations of Hypokamia
Definition
high blood sugar, plyuria and polydipsia , mscle weakness, cardia dysrhythmias,
Term
What is the treatment for hypokalemia
Definition
Eating foods rich in K and K replacement not to exceed 80meq a day if renal fun is norm.
Term
What changes happen on the ECG in regards to hypokalemia
Definition
amplitude of the T wave in decreased and U wave is increased st segment is depressed, in severe cases the P waves peak and QRS is prolonged.  It also increased r.f. dig tox
Term
Why do dysrhythmias occur
Definition
because K contributes to the repolar phase of the action pot, thus delaying ventricular repolarization.
Term
What are some of the treatments for hyperkalemia
Definition
glucose and insulin, Na bicarb, ca gluconate, cations exhange cations and resins
Term
If ECF concentration of K increases but ICF concentration K stays the same what happens to the resting membrane potential
Definition
the cell becomes more positive and the cell membrane becomes hypopolarized.  With mild increases in k the cell repolarizes more readily and becomes more irritable.  Action pot is easier because the difference between the resting membrane and threshold has been shortened.
Term
Where is calicum found at
Definition
Bone (hydrozyapatite and inorganic compound causes bone rigidity). , plasma (50% bound to plasma proteins and 40% free form)
Term
Which kind of ca2 has the most important function
Definition
ionized ca2
Term
Why is Ca2 important
Definition
structure of bone, enzymatic cofactor for bl. clotting, hormone secretion and fun of cell receptors.  Plasma mem stability and permeability are directly related to ca2 ions, transmission of nerve impulses and contraction of muscles.  ICF ca2 is primarly in the mitho.
Term
Where is phosphate found and what are norm serum levels
Definition
found in bones, 2.5-4.5 in adults, 6.0-7.0 as high in infants and children
Term
What fun.s does phosphate have
Definition
ICF and ECF anion buffer in the reg of acid base balance in the form of ATP it provides energy for muscle contraction.
Term
What is the formula for concentration of ca to phosphate
Definition

CA++× HPO=4=K+

If the concentration of one increases the concentration of the other decreases

Term
What hormones control Ca HPO=4
Definition
parathyroid, vit K and calcitonin.  Acting together these substances determine the am of ca and hpo4 absorpted from the intestines, the deposition and absorbtion in the bone, and reabsorption and excretion by the kidney
Term
How does PTH control ca2 and hpo4 levels
Definition
Decrease levels of pth cause decrease renal act of vit d when decreases reabsorption and decrease excretion of phosphate .  In hypocalcemia increase pth incease renal activation of vit d and increase reabsorption and increase excretion of phosphate
Term
Explain how vit d is activated
Definition
renal activation starts when levels of ca2 are decreased which stimulates secreation of pth  pth acts to stimulate ca2 reabsorption and excretion of phosphate.  activated d then comes in the plasma and acts to increase reabsorption of ca2 in sm intestine, increase bone absorption of ca2, and increase renal tubular reabsorption of ca2.
Term
when is vit d not activated
Definition
in kidney, renal failure
Term
What causes hypocalcemia
Definition
  1. Decrease in dietary intake of green leafty vegatables dairy products
  2. blood transfustions because the product they use to store binds with ca2
  3. pancreatitis because of release of free fatty acids which bind ca2
  4. neoplastic bone metastases
  5. vitamin d deficit
  6. metavolic or respitory alk
Term
What are the clinical manifestation of hypocalcemia and how are they primarily caused by
Definition
  1. chvostek sign by tapping on the facial nerve just behind temple a + sign is a twitch of the nose or lip
  2. trousseau sign is contraction of the hand and fingers when the arterial blood flow in the arm is occluded for 5 minutes
  3. convulsions and tetany
  4. ecg prolged QT interval
  5. hyperactive bowel sounds
Term
What is the treatment for hypocalcemia
Definition
  1. ca2 gluconate
  2. oral replacement
Term
What causes hypercalcemia
Definition
  1. hyperparathyroidism
  2. bone metastases
  3. prostate and cercvical cancer
  4. sarcoidosis
Term
what are s/s of hypercalcemia
Definition
  1. fatique
  2. anorexia
  3. nausea
  4. constipation
  5. behavioral changes
  6. impaired renal function
  7. shortened QT segment and depressed t waves
Term
What is the treatment of hypercalcemia
Definition
  1. oral phosphate
  2. normal saline iv
  3. corticosteriods mithramycin
Term
How is mg metabolism regulated
Definition
  • kidney
  • small intestines

 

Term
Who compensates in met acidosis and what does it do
Definition
the lungs compensate by breathing by increasing ventilations lowering h2co2 and paco2  and kidneys excrete the excess acid as ammonia
Term
what are some of the ss of med acid
Definition
  • ha
  • tireness
  • coma
  • severe deep rapid rr
  • dysrhymias
Term
how is met acid evualated and what is the treatment
Definition
if ph <7.36 and hco <=24.  If ph < 7.1 iv sodium hco3 is indicated
Term
What are some of the causes of met alkalosis
Definition
  1. nausea
  2. vomiting
  3. gastric suctioning
  4. excessive HCO3 intake
Term

Which met alk condition can not be treated by the kidneys and why

 

Definition
hypochloremic met alk  b/c vol dep of electroyles stim kidneys to reabsorb bicard and na while excreting h.  when there is no more K hydrogen enters into the cell and is also excreted to maintain balance.  The urine is acidic but the reabsorbed biccarb make it impossible to correct balance must give asolut of na with K.  This reduces the renal stim to reabsord Na and cl is replaced.  bicarb is excreted and H reabsorbed.
Term
How do you evual and tx met alk
Definition
met alk is evual when bicard level is greater than 26 ph >7.45 rr compen is when pco2>40 in hypochloremci alk a na iv sol in hyperadlosteronism K is required to move H to move back into the ECF and < loss of H from distal tubule.
Term
How do the kidneys compensate in resp acidosis
Definition

They sec H  and regenerate bicarb, bicarb and pco are elevated and ph will return to norm

 

Term
treatment rep acid
Definition
mech ventilation
Term
Hypocapnia
Definition
excessive reduction of co2
Term
hypercapnia
Definition
excessive  CO2
Term
what is the evual and treatment of resp alk
Definition
ph>7.45, and Pco<38 with compensation a < in bicarb levle treating the ph
Term
what disease processses mostly cause resp. alk
Definition
chf, pulmonary dz, fever, anemia, thyrotoxicosis, cirrhosis
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