Lecture 10: Fluid Balance Flashcards
Where is the highest volume of water located in the body?
brain & kidneys
Where is the lowest volume of water located in the body?
teeth
Is 60% of water mostly intracellular or extracellular?
intracellular
Where is 40% of water found in the body?
- 8% in blood plasma
- 32% in CSF, lymph, eyes, parietal, peritoneal, synovial fluid
Is Na+ extracellular or intracellular?
extracellular
Is Cl- extracellular or intracellular?
extracellular
Is Mg, potassium, & ATP production extracellular or intracellular?
intracellular
Where are most of our extracellular proteins found?
blood plasma
How do you gain water?
comsumption & metabolism -> 2.5 L
How do we lose water?
- ventilation
- sweat
- urine & feces
What occurs if water loss exceeds water gain?
solute conc. increase = dehydration
What happens when you get thirsty?
- decrease in blood volume & pressure
- increase in plasma osmolarity ->increase heartrate, release of vasopressin, decrease saliva
- water lost from deep tissues
What are osmoreceptors?
- transmit signals to hypothalamus
- triggers thirst response
- triggers salivary glands to reduce secretion
- triggers antidiuretic hormone -> vasopressin
What is vasopressin?
- reduces blood flow to extremities & increase blood pressure in arterioles
- acts on collecting ducts of nephrons to increase aaquaporins
What are 2 diuretics that inhibit vasopressin?
alcohol & caffeine
How do dehydrated kidneys secrete renin?
triggered by macula dense of nephron which monitors NaCl conc.
What is the role of renin?
- sodium reabsorption
- water retention
What is the role of angiotensin?
- increase aldosterone release form adenal cortex
- triggers vasoconstriction
What are ACE inhibitors?
block angiotensin -> NO vasoconstriction -> keeps BP low
What is the major cation in extracellular fluid?
Na+
* responsible for most osmotic pressure, cell signaling, membrane pot., thermoregulation
What is the major cation in intracellular fluid?
K+
* establishes resting membrane pot. in neurons & muscle fibers
How are Na+ & K+ levels regulated?
by aldosterone & angiotensin 2 (responds or low Na+ or high K+)
hat is the major anion in extracellular fluid?
Cl-
* maintain neutral charge
* plays role in hyperpolarizing neurons
* needed for neutral charge in blood -> chloride shift (when bicarb comes out & Cl- goes in)
What maintains blood pH?
HCO3- (bicarb)
What are the roles of Ca2+?
- bone, enamel, dentin
- triggers release of neurotransmitters
- muscle contraction -> binds tropin or calmodulin
- triggers clotting factors
- cofactor to enzymes
Where is the majority of HPO4 found?
- bones
- phospholipids, nucleotides, & ATP
- buffers
