7/14 Acid Base, fluids, electrolytes, kidneys

explain why acid base balance is important

narrow PH is needed for optimal reactions: chemical, elctrical, and enzymatic

if ph is abnormal reactions become slow, ineficient, or stop and muscle contractions fail.

abnormalities are major cause of death in shock and respiratory disease

where does acid in the body come from

metabolic processes release H and Co2

lactic acid

ketones

etc

Normal ranges for human

ph

HCO3

pCO2

ph 7.35-7.45 (6.9-8 is livable)

HCO3 22-26

pCO2 35-45

buffer

a chemical songe that soaks up extra H. Blunts big shifts in PH

list 3 homeostatic mechanisms used to maintain acid base balance

chemical buffers- bicarbonate/carbonic acid buffering system works within seconds

respiratory- acts quickly works within minutes

renal/kidneys- works within hours to days. Most effective

chemical formula for bicarbonate/carbonic acid buffering system

C02 + H2O — H2CO3 — H + HCO3

H2CO3 = carbonic acid

HCO3- bicarbonate

when the respiratory system fails and holds onto co2, what happens

what if it looses to much CO2

the co2 gets converted to H in the formula. The H goes to the kidneys. They excrete hydogen and absorb CO3/produce more.

The lack of hydrogen will be detected and the kidneys will excrete/stop making CO3 and retain H.

Explain how the body senses the change in PH

central chemoreceptors in the medulla oblangata monitors H levels in CSF

The chemoreceptors stimulate the dorsal resp group to alter RR and depth

Respiratory acidosis

causes, s/s, body response, and treatment

causes: resp depression, sedative OD, asthma, COPD, FBAO, etc

s/s: hypoventilation, high ETCO2, dim breath sounds, pallor/cyanosis, low SPO2, headache, restlessness.

kidneys retains/makes CO3 and secretes H

Treatment: PPV increase rate and depth. Treat the cause.

resp alkalosis causes, s/s, body response, and treatment

causes: hyperventilation- pyschogenic, PE

s/s- hyperventilatuion, low ETCO2, lightheaded, dizzy, anxiety, fear, tingling of hands, feet, or face, cramps

body retains H and secretes CO3

treatment:coach breathing, do a better physical exam.

metabolic acidosis

causes, s/s, body response, and treatment

cause: lactic acidosis (anaerobic resp), sepsis, DKA, renal failure, ASA overdose, poop out too much HCO3

s/s symptoms from the cause, increase RR, headache, lethargy, N/V/D

body breaths off co2- some renal compensation as well

treat the cause, fluids

metabolic alkalosis

causes, s/s, body response, and treatment

prolonged vomiting (loose too much acid), dieuretic use, excessive TUMS,

symptoms from cause, irritation, twitching, N/V/D, weakness, muscle cramps, low RR and depth

treat the cause

ABG stuff

if etco2 is high and PH low- resp acid

if stco2 is low and PH high- resp Alk

If CO3 is low and PH low- meta acid

if CO3 is high and PH is high- meta alk

can be partially comp if alternate system is high or low but PH is still out of range

fully compensated is when alternate system gets it back in range (COPD has this a lot)

Mixed acid or alk can happen where its both meta and resp

5 functions of the urinary system

formung and eliminating waste

maintaining blood volume with propermba;ance of water, electrolytes, and PH

retaining key compunds such as glucose while excreting waster such as urea

controlling arterial BP

production of hormones

location of kidneys

lie posteriorly on either side of vertebral collumn in retroperitoneal space. right kidney is behind the liver and the left kidney is behind the spleen (higher up)

functional unit of kidney? How many?

nephron

1 mil per kidney

75% are not used at one given time (for when old ones die)

where does most reabsorbtion take place

proximal tubule.

things like sugar, Amino acids, sodium, potassium, water, hydrogen, bicarbonate

list 3 processes of urine formating

glomerular filtration- plasma fitered out of golmer.

tunular reasbsorbtion- moves stuff back to capillaries it wants to keep

tubular secretion- gets rid of everything else it doesnt want

what 2 lab tests can show decreased kidney function

BUN-blood urea nitrogen high means kidneys arent filtering it well

Creatnine- same as above

explain the 2 types of diuretics and how they work

loop diuretics (lasix/furosemide) blocks reabsorbtion of Na, K, and Cl in loop of henle. keeps water in the loop which keeps more water. Unfortunately this makes us loose more electrolytes too.

Thiazide diuretics (diuril)

reduces Na reabsorbtion in distal convoluted. tubule. Keeps Na is urine so water follows.

5 extrinsic factors of renal regulation

BP- more BP = more hydrostatic pressure and more GFR. vise versa

aldosterone- tells kidneys to retain sodium and more water as a result. excretes potassium. From adrenal gland. Comes from elevated potassium.

ADH- posterior pituitary releases it when osmolarity of blood is too thick. Acts at distal tubule and collecting duct makes water pores open up and water leaks into medulla. Does not influence Na movement.

ANP (atrial natriuretic peptide)- causes a decrease in BP and blood volume by excreting sodium. Atria sense too much pressure

PTH (parathyroid hormone)- causes calcium to elevate in blood stream. Tells kidneys to retain/reabsorb calcium and get rid of phosphate.

Renin angiotensin aldosterone system

juxtamedullary apparatus senses a decrease in hydrostatic pressure

tells kidneys to release renin

renin meets angiotensinogen in the blood stream (produced by liver) and turns into angiotensin 1. This goes to the lungs where it meets angiotensin converting emzyme (ACE) and turns to angiotensin 2.

Angiotensin 2 causes vasoconstriction and releases aldosterone.

function of kidney in preserving acid base

reabsorbs or excretes bicarb and H

how much of our body is water? Where is most water at?

60%

2/3 (65%) of water in intra cellular

1/3 is extracxellular with 80% (25% total) of that being the intersticial fluid and 20% (8.3% of total) being the blood

how does kidney disease cause hypertension

the kidneys dont have enough GFR so constantly causing RAAS to activate but it doesnt help

how does RAAS effect CHF

CHF causes low BP, so RAAS kicks in which overloads the heart and the fluid backs up

as we age do we have more or less water

less

3 parts of body fluids and reasons for a fluid system

solute + solvent = solution

the ability to disolve substances in a medium

move particles and substances

required for biological processes

2 types of particles found in solutions

crystalloid- aqueous solitions of minerals, salts or other soluble things (breaks down)

colloids- has bigger particles such as protiens dispersed throughout (doesnt break down)

what s 3rd space fluid loss

space in body where fluid is not normally at in large amounts.

pulmonary edema

fluid in belly

pedal edema

what causes hydrostatic pressure?

the heart

starlings hypothesis

net filtration = forces favoring filtration - forces opposing

s/s of over and underhydration

under

• dry mucous membranes

• signs of shock

• sunken fontenells

• decreased urine output

• sunken eye

• lethargy

over

• edema

• chest pain (heart is working to hard)

• AMS

what is an electrolyte

substance that dissociates into electcally charged ions.

cat- pos

an- neg

capillary oncotic pressure is strongest where

same everywhere- seen more on veinous side

sodium

main extracellular cation

influences water distrib.

hyponatremia

low sodium - innappropriate ADH secretion, excess water intake

Central nervous system

osmosis makes water swell the cells

difficulty concentrating, lethargy, confusion, headache, seizures, muscle cramps, tachycardia, N/V, increased ICP

hypernatremia

high sodium

diabetes, fluid loss, salt ingestion

irritability, decreased LOC, lethargy, delerium, seizures, coma. If dehydration is cause look for those signs as well.

potassium

main intracellular cation

s/s are more in heart

regulates cell excitability

hypokalemia

low potassium

diarrhea, vomiting, diuretics, excessive sweating, insulin admin

muscle weakness, hypoflexia, GI issues, cramps, cardiac dysrhythmias, small inverted t waves, ST depression.

hyperkalemia

high potassium

burns, renal failure, crush injuries

generalized fatigue, oliguria (decreased urine), nausea, diarrhea. Cradiac arrest, bradycardia, peaked t waves, widening of QRS, flattened P waves.

calcium

both inside and outside cell

s/s more PNS

effects cell membrane permeability- especially in nerve signal transduction

hypo and hypercalcemia

hypo

acute pancreatitis, lack of PTH, renal failure.

n/v/d, numbness and tingling around mouth or in fingers and toes, muscle cramps

hyper

hyperparathyroidism, excess vitamin D

fatigue, weakness, lethargy, renal stones, behavioral changes