Fluid compartments and Solutes

Question 1

Which cation is found in much higher concentrations extracellularly than intracellularly

Answer 1

Sodium ions are found in much higher concentrations extracellularly than intracellularly

Question 2

Which cation is found in much higher concentrations intracellularly than extracellularly

Answer 2

Potassium ions are found in much higher concentrations intracellularly than extracellularly

Question 3

How is the intracellular high potassium neutralised

Answer 3

By anions like negatively charged large molecules like DNA and proteins, phosphorylated proteins etcetera

Question 4

What is the main intracellular and what the main extracellular anion

Answer 4

The main extracellular anion is chloride and the main intracellular anion is phosphate (bound to organic compounds)

Question 5

How much more protons are found intracellularly than extracellularly and what is difference in pH

Answer 5

The difference in pH between blood plasma and cytoplasm is 0.3 (7.1 in cells, 7.4 in plasma) which is equivalent to approximately twice the protons in cells compared to extracellularly

Question 6

What is the exception to identical osmolarity intracellularly and extracellularly

Answer 6

Identical osmolarity seen between cells and extracellular fluid is not seen in the kidneys where the excreted fluid is much more concentrated than intracellular osmolarity

Question 7

What is the unit for osmolarity and is its definition

Answer 7

Osmol/L is the unit for osmolarity and it is defined as the number of moles of particles dissolved into a solution

Question 8

Why is tonicity much more determinant than osmolarity in biological systems

Answer 8

Because in biological system permeability of membranes plays a role, osmolarity does not appropriately account for the outcomes of differences in osmolarity

Question 9

How is the cell prevented from bursting despite higher intracellular concentration of impermeant solutes

Answer 9

The Na/K-pump actively pumps out sodium ions that flow down their concentration gradient to establish no net movement of sodium ions that therefore maintain a dynamic equilibrium in which there is higher intracellular concentration of impermeant solutes

Question 10

When organs are donated, to what temperature is the organ cooled

Answer 10

Organs for donation are cooled to around 4 degrees Celcius

Question 11

What is the function of the University of Wisconsin solution

Answer 11

The University of Wisconsin solution prevents organ cells from hypothermic swelling and enhance the preservation for transplantations

Question 12

What three main factors in the UW-solution reduce swelling

Answer 12

The absence of sodium of chloride ions in the solution prevent an influx of sodium that can make membrane lose integrity, impermeant solutes like lactobionate and raffinol equalise osmolarity and starch acting as colloids to maintain high osmolarity in vascularity to prevent oedema

Question 13

What is the function of allopurinol and glutathione in UW-solution

Answer 13

Allopurinol and gluathione serve as antioxidants to prevent against damage from reactive oxygen species that are released in hypothermic state

Question 14

What happens to cell when Na/K-pump stops functioning

Answer 14

When Na/K-pump stops functioning, sodium ions start entering the cell and potassium starts the leaving the cell and water will follow the inward flow of sodium and this causes the membrane to lose its integrity and burst and this results in cell death

Question 15

How does fluid leak out of vascular endothelium

Answer 15

Fluid can leave the capillaries through small pores between endothelial cells

Question 16

How do lipid-soluble substances pass the vascular endothelium

Answer 16

Lipid-soluble substances pass through the endothelial cells to leave the capillary

Question 17

How do certain proteins pass the vascular endothelium

Answer 17

Exchangeable proteins are transported through endothelial cells in vesicles that are transported from the luminal side of endothelial cell to outside into the tissue

Question 18

What is colloid osmotic pressure

Answer 18

The osmotic pressure created in blood plasma by large insoluble plasma proteins that increase the blood plasma osmolarity such that only limited amounts of fluid leave capillary

Question 19

By what force are molecules pushed out of capillary pores

Answer 19

By hydrostatic pressure that is caused by pumping of the heart, fluid and molecules are pushed out of capillary pores

Question 20

What does the term oedema describe

Answer 20

Excess loss of fluid from a capillary into the interstitial space, due to loss of colloid osmotic pressure

Question 21

How can increased permeability of capillary walls lead to oedema

Answer 21

In increased permeability plasma proteins that maintain the colloid osmotic pressure are lost, which means there is less resisting force of fluid leaving the capillary and the blood and this leads to excess fluid loss to the interstitial space

Question 22

Why does interstitial fluid flow into lymphatic capillaries

Answer 22

Lymphatic capillaries have a lower internal pressure than the interstitial fluid, which leads to a net movement of the fluid into the capillaries

Question 23

What is the order of the lymphokinetic motion

Answer 23

The blood flows into interstitial fluid, which flows into lymphoid capillaries, which flows into lymphoid veins, which flows into lymphoid ducts which empties in the bloodstream in large veins

Question 24

In what two ways can lymph fluid be returned to the blood circulation

Answer 24

Lymphoid fluid can be returned to the blood circulation via lymphatic ducts emptying in large veins or via lymph nodes where lymphoid fluid can be returned through capillaries

Question 25

In what two places do lymphatic ducts release lymphatic fluid into blood circulation

Answer 25

The thoracic duct empties lymph into the left subclavian vein and the right lymphatic duct empties lymph into the right subclavian vein

Question 26

How can high blood pressure lead to oedema

Answer 26

High blood pressure leads to higher hydrostatic pressure in capillaries and because this is pushing fluid out, the same colloid osmotic pressure cannot counteract this and there is excess fluid loss to interstitial space and tissues

Question 27

How can treatment of breast cancer lead to oedema

Answer 27

In carcinomas tumours often spread via the lymphatic system, so breast draining axillary lymph nodes are often removed and because the lymphoid fluid can then not be removed this leads to build up of lymphoid fluid and oedema in the arm

Question 28

What is the cause and the consequence of elephantiasis

Answer 28

In elephantiasis parasitic worms block the lymphatic veins and this leads to build up of lymphoid fluid and this results in expansion of the tissue that cannot be drained