Fluid and Electrolyte Balance PPT

what is the main fluid component in our body

water

water is __% of out body weight

60

most of the water is in the ___

ICF

__________ contribute most to solute concentration of fluids

electrolytes (sodium, potassium, chloride, etc)

3 major aspects to control water balance

• excretion from kidneys

• ADH

• thirst

3 components in the thirst center that increase water intake

osmoreceptors, dry mouth, blood volume decrease

osmoreceptors

receptors in the hypothalamus that detect ECF osmolality

Antidiuretic Hormone (ADH)

increases water reabsorption in the collecting ducts; controlled by plasma osmolality and blood volume

plasma osmolality increased, this is detected by __________ and ___ is released

osmoreceptors; ADH

______ is the most abundant cation in the ECF

sodium

sodium largely determines _________ of ECF

osmolality

stimulants of renin

• low BP

• sympathetic nerve innervation to JG cells

• macula dense cells detecting low fluid delivery (includes low Na)

does RAAS conserve or deplete Na

conserve

atrial natriuretic peptide (ANP)

• released upon stretch of the atria in the heart

• increases Na excretion

atrial natriuretic peptide (ANP) causes what 4 things

1. increase in GFR and inhibits Na reabsorption

2. inhibits secretion

3. diminishes renin release

4. vasodilator (decreases BP)

renal sympathetic nerves

reduces renal Na excretion causing 3 things

1. decline in GFR → less Na filtered → less Na secreted

2. increases Na reabsorption in the tubules

3. stimulates renin release → increased Na reabsorption

hyponatremia

technically low blood sodium but generally reflects too much water content in plasma

hypernatremia

excess sodium in blood (hypertonic blood)

potassium is the most abundant ion in the ____ and a major determinate of volume there

ICF

_________ largely maintains K balance

kidneys

potassium is important for membrane potentials,,, low K in the plasma (hypokalemia) leads to what

hyperpolarization → reduced excitability → muscle weakness

potassium is important for membrane potentials,,, high K in the plasma (hyperkalemia) leads to what

depolarization → increased excitability

if the Na/K pump is inhibited what may result

hyperkalemia (too much K in the plasma) because the K is not getting pumped into the cells

__________ promotes K update by skeletal and liver cells, stimulates Na/K pumps, and can be administered with glucose to treat hyperkalemia

insulin

__% of calcium is free and __% of that filters through glomeruli

50; 50

most Ca is reabsorbed in ____

PCT

low ___ impairs Ca reabsorption

K

extracellular Ca binds to voltage gated sodium channels and does what

keeps the channels closed/less likely to open

hypocalcemia

low levels of Ca which allows more Na into cell

hypercalcemia

high levels of Ca which blocks enough Na from entering the cell

trousseau’s sign

carpopedal spasms following inflation of BP cuff results from hypocalcemia

factors influencing Ca balance

parathyroid hormone, vit D, cancers

lymphatic system

• assists with immune function and extracellular fluid drainage in conjunction with the circulatory system

• carries lymph through vessels and nodes to return it to the bloodstream

the lymphatic system returns _________ that leaked out of the vascular system back to ________

fluid; blood

if fluid does not return to blood then we lose blood volume

vessels carry lymph how

by contracting and relaxing via smooth muscle or contractile endothelial cells

lymph nodes

masses of bean shaped lymphatic tissue that store lymphocytes and macrophages to attack bacteria and viruses

lymph travels through the ______ and kills pathogens

nodes

organs that help with immune function that are considered lymphatic organs

thymus, spleen, bone marrow

fluid dynamics

1. lymphatic vessels pick up fluid from blood vessles

2. arteriole end has main HP pushing fluid out because HP here is greater than the interstitial fluid and venous fluid

3. venous ends also exert HP on fluid for circulation, but this is not driving the net pressure

lymphedema

accumulation of lymph leading to swelling

primary lymphedema

• genetic

• absent or malformed lymphatic tissues

• no effective treatments but compression stockings and pumps can help manage

secondary lymphedema

• several causes

• function can resume if cause is removed

• compression stockings and PT is helpful treatment

lymphomas

cancers beginning from lymphocytes within lymphatic system

hodgkins lymphoma

abnormal B lymphocyte (reed sternberg cell)

non-hodgkins lymphoma

90% of lymphomas (no reed sternberg cells present)

edema

widespread accumulation fo salt and water in interstitial spaces of the body

edema is mostly caused by what

changes in starling forces; retention of water and water by kidneys

causes of edema

• increases capillary HP

• decreased capillary OP

• increased capillary permeability leading to loss of plasma proteins

• obstruction of lymphatic flow

heart failure

reduced cardiac output and blood flow to tissues

heart failure and edema activate what

they activate RAAS to increase BP and sodium/water reabsorption

______ is common in ppl with chronic kidney disease

edema

pitting edema

skin leaves indentation when pressure is applied (more common in heart and kidney failure)

non-pitting edema

associated with conditions of the thyroid or lymphatic system

• lymphedema

• mxyedema

• lipedema

mxyedema

associated with hypothyroidism (lack of thyroid hormone) leading to fluid buildup

lipedema

abnormal buildup of adipose tissue in arms and legs (more common in females)

deep vein thrombosis (DVT)

traveling clot blocking blood flow usually in lower extremities or pelvis

pathology of thrombus formation

endothelial/vessel injury, stasis (blood flow slows/stops), hypercoagulability (thick blood)

what can effect hypercoaguability

increase in number of prostaglandins and decrease in number of coagulants

_________ determines risk of developing DVT

Well’s Criteria

those with __________ are at a higher risk for DVT

chronic kidney disease

look at image

look at image