Physiology: Volumes and Composition of Bodily Fluids

Describe Homeostasis

the state of steady internal, physical, chemical,
and social conditions maintained by living systems. This is the condition of optimal functioning for the organism and includes many variables such as body temperature and fluid balance, being kept within certain
pre-set limits (homeostatic range).

Describe Negative Feedback

Reverses a change in a controlled condition

-to normal range, most systems: BP, blood glucose, temp, etc.

Describe positive feedback

strengthen or reinforce a change in one of the body’s controlled conditions

-blood clotting, cytokine storm, normal child birth.

-Often happens at very specific condition

Describe homeostasis controls

Successful compensation: homeostasis reestablished

Failure to compensate: illness & death

____ is the study of failure to compensate

pathophysiology

Homeostasis does not mean ________

Equilibrium:

Osmotic equilibrium
Chemical disequilibrium: more K+ intracellular, more Na+, CL-
extracellular
Electrical disequilibrium: -7o mV intracellular

The volume and the components in the body fluid are
kept in a pre-set limit.

ex: central control of water and sodium excretion in urine through actions of specific hormones. Central control of water and NaCl consumption motivated by thirst and salt appetite.

The body fluids in different ________ are
separated by __________nd capillary wall

different, plasma membrane

What are the components of the body fluids?

1. Water (the solvent)
2. The molecules (solutes) dissolved in H2O
-Electrolytes (positive or negative charged ion: sodium, potassium,
ect).
-Proton, H +
-Metabolites (urea, glucose, ATP, nucleotides, amino acids, ect)
-Proteins (albumin, hormones, antibodies)
-Gas: carbon dioxide, oxygen

water accounts for the ____________ of
the body fluids, also account for ______ weight of the whole body

total volume and main weight, 45-65% of the whole body

Water is a vital nutrient to life first acts as ______ for most ________ and _____ molecules

solvent, organic, and inorganic

water _______ our internal body temp by ________ and ________

regulates, sweating, and respiration

The ________ and _______ that our bodies use as food and oxygen/co2 are transported by ______ in the bloodstream

carbs, proteins, water

Other functions of water are?

It assists in flushing waste mainly through urination
•acts as a shock absorber for brain, spinal cord, and fetus
•forms saliva
•lubricates joints

Why do women on average have a lower percentage of water weight than males?

Females typically have 8% thicker
hypodermis (more adipose) than
males. Thus, females have more
cells (adipocytes) that contain less
water

Why does the water content, on
average, decrease as we age?

• In general, we put on more fats (adipose)
as we age (at least to age 60).

Describe Protein in terms of intracellular and extracellular compartments

Protein concentration is high in intracellular and plasma, but low in interstitial fluid.

Why is protein high intracellularly?

Protein in our body fluids are made inside of the cells. Most proteins made by the cell are delivered intracellularly (only a small% of proteins are extracellular due to signal peptide and protein sorting).

plasma membrane does not allow passage of proteins.
Plasma membrane does not allow free passage of charged molecules and large polarized molecules (proteins and others).

But allow H2O (slow) and gas as well as hydrophobic molecule pass)

Where do plasma proteins come from? Why is interstitial fluid low?

Plasma proteins are mainly made by liver cells (for example albumin) and lymphocytes (immunoglobulins) and these are extracellular, and enter the blood. Proteins are not allowed to pass capillary wall despite its leakage (molecules with small size, even ions, can enter the interstitial
fluid via capillary wall, due to the leakage of endothelial cells).

Describe ions and