Role of water in the body
all water is used as a medium to carry solutes, like electrolytes and metabolites, throughout the body
How is water distributed throughout the body?
2/3 - intracellular compartments - inside cells
1/3 - extracellular compartments - outside cells
Examples of Extracellular compartments (ECF)
1. interstitial spaces
4. fluid in the eyes
5. synovial fluid in joint capsules
6. cerebrospinal fluid
7. serous fluids in cavities
9. glandular secretions - medium that carries hormones
Intracellular Fluids (ICF) contain what types of substances?
How does water shift with solute?
1. movement of solutes will shift water by osmosis
2. solvent drag - fluid will shift solutes
Where do we get all that water from?
10% from metabolic reactions like aerobic respiration
90% from oral consumption
- maintained by the Hypothalamus within Thirst Center that alerts the body for the need of water
Regulation of Thirst Reflex
1. Osmoreceptors - cells that monitor the osmolarity of bodily fluids
2. Baroreceptors - cells that monitor BP (↓BP will trigger thirst reflex to add more volume to blood)
How is thirst reflex suppressed?
stretching the stomach and moistening of oral mucosa will suppress thirst reflex immediately.
1. insufficient amounts of water either by lack of consumption, elevated temperatures, or high activity
3. body will compensate by removing H₂O out of ICF and into ECF
1. 61% in urine
2. 4% in poop
3. 35% by respiratory tract (exhalation) and skin (sweat)
1. sweat glands secrete sweat
2. excretory mechanism
3. shedds - NH₄, Urea, K⁺, and Na⁺ - forming acid mantle
1. tiny amounts of sweat shedding at all times
2. not noticeable
3. important for heat regulation
4. lowers body temperature
5. each day .5L of water is shed this way
1. ↑ temp will ↑ sweat by 100-150mL
3. associated withe exercise and hot environments
4. an increase in activity can increase visible sweat by 8-10L/day
Affects of BP on Osmolarity
1. ↑ BP will ↑ Glomerular Pressure to ↑ filtration, and pass out more water in urine which will lead to ↓ BP
2. ↓ BP which ↓ Glomerular which will ↓ filtration which will ↓ urine flow. A result is to trigger thirst reflex to ↑ BP.
1. ions or molecules with electrical charges
ie) Na⁺, K⁺, Ca²⁺, Cl⁻, PO₄³⁻
2. electrolytes concentrations will change during weight changes and growing stages
Where are electrolytes stored?
2. mainly Ca²⁺ and PO₄³⁻
3. downfall is that bone can also store Pb, As, and Hg
1. Cation in ECF
2. involved in sodium-potassium pump
3. vital for glucose absorption
4. essential for muscular contraction
6. maintains pH balance with Cl⁻
how much do we actually consume?
1. 15-20g/ day
2. excess is removed via kidneys and sweat
3. regulated by ANH and Aldosterone
Causes of Hyponatremia
- poor diet
- severe burns
- insufficient Aldosterone secretion
- excessive urination
- Hyperglycemia- ↑ blood sugar
Hypernatremia leads to
- dry mucous membranes
- ↑ body temperature
- bounding pulse
- tendencies toward edema
- death at extremely high Na⁺ levels
1. pH balancer in the body
2. Cl⁻ compounds activate digestive enzymes made of gastric juices
3. can be exhaled, excreted by the kidneys and skin