PHGY 216 Final Exam – Complete Study
Guide with Practice Questions & Detailed
Answers|| GRADED A+|| LATEST UPDATE
2026
body bluid- two major compartments.
Intracellular Fluid (I C F)
-This is the fluid within cells and comprises about two thirds of total body fluid
-Extracellular Fluid (E C F)
-fluid surrounding the cells which includes the plasma, the interstitial fluid, lymph, and
transcellular fluid
-comprises about one third of total body fluid
-plasma is about one fifth of the E C F, the interstitial fluid is about four fifths of the E
C F, and the lymph and the transcellular fluid are considered negligible.
-BARRIERS BETWEEN BODY-FLUID COMPARTMENTS
-Barriers between the plasma and the interstitial fluid
-separated by the blood vessel walls.
-everything in the plasma (except proteins) can freely exchange with the interstitial fluid
through capillaries
-thus, the composition of the plasma and the interstitial fluid
are identical, except plasma proteins
-Barriers between the intracellular fluid and the E C F
-barrier is the plasma membrane that surrounds each cell in the body
,-I C F contains proteins that do not exchange with the E C F
-unequal distribution of ions across this barrier (i.e. K+ in ICF, Na+ greater in ECF)
-2 main factors to regulate fluid balance
-ECF determines exchange of substance into the ICF
-overall control of fluid balance is dependent upon regulating the E C F.
-E C F Volume
-closely regulated to maintain blood pressure
-maintenance of salt balance is important in the long-term regulation of E C F volume
-E C F Osmolarity
-closely regulated to prevent the swelling or shrinkage of cells.
-CONTROL OF E C F VOLUME
-E C F volume directly influences blood pressure by changing plasma volume
-Increasing E C F volume increaes blood pressure
-there are short term and long term control factors
-Short-term Control Factors
1. The Baroreceptor Reflex
-mechanoreceptors located in the carotid artery and the aortic arch
-they detect changes in arterial blood pressure
-baroreceptor reflex regulates blood pressure
-when pressure low, cardiac output (CO) and total peripheral resistance (TPR) increase,
and vice versa when low
2. Fluid Shifts
-shift fluids from interstitial compartments to blood vessels to increase pressure
,-Long-term Control Factors
1. Fluid Input/Output
-long-term regulation of blood pressure is a primary function of the kidneys and
the thirst mechanism, controlling fluid output and input
-i.e. urine output
-CONTROL OF SALT
-Sodium, and the anions that are associated with it (mainly chloride), account for more
than 90% of the E C F’s solutes
-ECF volume controlled by salt levels due to osmosis
-Salt Input
-Regulation of salt input is poor as it is dependent upon dietary salt.
-0.5g/day for normal activity and higher for physical activity is needed for body
-Salt Output
-excess salt must be eliminated, which occurs in the kidneys
-three pathways to eliminate salt are in the feces, sweat, and the kidneys.
-kidney has greatest role
-what do you think would occur if there was an increase in water in the E C F?
-If there were an increase in water in the E C F, the osmolarity would decrease and the
E C F would become hypotonic, meaning it would have a lower osmotic pressure than
the surrounding cells. This would result in water moving into the cells until the osmotic
pressures were equalized. This movement of water into the cells would cause them to
expand.
If the E C F were very hypotonic, the amount of water moving into cells would cause
, them to burst.
As already mentioned, the cellular consequence of hypotonic E C F is the swelling,
which impairs cellular function.
-HYPOTONICITY
definition: hypotonicity is when ECF has a lower osmotic (more water, less salts)
pressure than fluid inside the cell, and thus water from the ECF will enters the cell
-usually associated with overhydration, or excess free H2O
-three major causes
-Renal Failure
-These individuals are not able to produce a concentrated urine
-Rapid Water Ingestion
-can occur in healthy individuals if they drink volumes of water in excess
-Over Secretion of Vasopressin
-Vasopressin promotes water retention
-Using what you have learned thus far in the course as well as past experience,
come up with a few causes for hypertonicity.
-1. Insufficient water intake, or not drinking enough.
2. Diabetes insipidus, which involves a deficiency in vasopressin.
3. Excessive water loss due to heavy sweating during extreme exercise, prolonged
bouts of vomiting, or diarrhoea.
-Suppose that a patient with a normal osmotic balance is given a therapeutic
intravenous administration of an isotonic solution.
Using what you have learned thus far, answer the following questions:
Guide with Practice Questions & Detailed
Answers|| GRADED A+|| LATEST UPDATE
2026
body bluid- two major compartments.
Intracellular Fluid (I C F)
-This is the fluid within cells and comprises about two thirds of total body fluid
-Extracellular Fluid (E C F)
-fluid surrounding the cells which includes the plasma, the interstitial fluid, lymph, and
transcellular fluid
-comprises about one third of total body fluid
-plasma is about one fifth of the E C F, the interstitial fluid is about four fifths of the E
C F, and the lymph and the transcellular fluid are considered negligible.
-BARRIERS BETWEEN BODY-FLUID COMPARTMENTS
-Barriers between the plasma and the interstitial fluid
-separated by the blood vessel walls.
-everything in the plasma (except proteins) can freely exchange with the interstitial fluid
through capillaries
-thus, the composition of the plasma and the interstitial fluid
are identical, except plasma proteins
-Barriers between the intracellular fluid and the E C F
-barrier is the plasma membrane that surrounds each cell in the body
,-I C F contains proteins that do not exchange with the E C F
-unequal distribution of ions across this barrier (i.e. K+ in ICF, Na+ greater in ECF)
-2 main factors to regulate fluid balance
-ECF determines exchange of substance into the ICF
-overall control of fluid balance is dependent upon regulating the E C F.
-E C F Volume
-closely regulated to maintain blood pressure
-maintenance of salt balance is important in the long-term regulation of E C F volume
-E C F Osmolarity
-closely regulated to prevent the swelling or shrinkage of cells.
-CONTROL OF E C F VOLUME
-E C F volume directly influences blood pressure by changing plasma volume
-Increasing E C F volume increaes blood pressure
-there are short term and long term control factors
-Short-term Control Factors
1. The Baroreceptor Reflex
-mechanoreceptors located in the carotid artery and the aortic arch
-they detect changes in arterial blood pressure
-baroreceptor reflex regulates blood pressure
-when pressure low, cardiac output (CO) and total peripheral resistance (TPR) increase,
and vice versa when low
2. Fluid Shifts
-shift fluids from interstitial compartments to blood vessels to increase pressure
,-Long-term Control Factors
1. Fluid Input/Output
-long-term regulation of blood pressure is a primary function of the kidneys and
the thirst mechanism, controlling fluid output and input
-i.e. urine output
-CONTROL OF SALT
-Sodium, and the anions that are associated with it (mainly chloride), account for more
than 90% of the E C F’s solutes
-ECF volume controlled by salt levels due to osmosis
-Salt Input
-Regulation of salt input is poor as it is dependent upon dietary salt.
-0.5g/day for normal activity and higher for physical activity is needed for body
-Salt Output
-excess salt must be eliminated, which occurs in the kidneys
-three pathways to eliminate salt are in the feces, sweat, and the kidneys.
-kidney has greatest role
-what do you think would occur if there was an increase in water in the E C F?
-If there were an increase in water in the E C F, the osmolarity would decrease and the
E C F would become hypotonic, meaning it would have a lower osmotic pressure than
the surrounding cells. This would result in water moving into the cells until the osmotic
pressures were equalized. This movement of water into the cells would cause them to
expand.
If the E C F were very hypotonic, the amount of water moving into cells would cause
, them to burst.
As already mentioned, the cellular consequence of hypotonic E C F is the swelling,
which impairs cellular function.
-HYPOTONICITY
definition: hypotonicity is when ECF has a lower osmotic (more water, less salts)
pressure than fluid inside the cell, and thus water from the ECF will enters the cell
-usually associated with overhydration, or excess free H2O
-three major causes
-Renal Failure
-These individuals are not able to produce a concentrated urine
-Rapid Water Ingestion
-can occur in healthy individuals if they drink volumes of water in excess
-Over Secretion of Vasopressin
-Vasopressin promotes water retention
-Using what you have learned thus far in the course as well as past experience,
come up with a few causes for hypertonicity.
-1. Insufficient water intake, or not drinking enough.
2. Diabetes insipidus, which involves a deficiency in vasopressin.
3. Excessive water loss due to heavy sweating during extreme exercise, prolonged
bouts of vomiting, or diarrhoea.
-Suppose that a patient with a normal osmotic balance is given a therapeutic
intravenous administration of an isotonic solution.
Using what you have learned thus far, answer the following questions:
