Movement of molecules around the body

Question 1

What are the 3 main fluid compartments?

Answer 1

1) intracellular 2) Extracellular - divided into 2 compartments - Interstitial - Plasma

Question 2

What makes up 1/3 of the Total body weight?

Answer 2

extracellular fluid 3/4 extracellular = interstitial 1/4 extracellular = intravascular

Question 3

What makes up 3/4 of the total body weight?

Answer 3

Intracellular = water, solutes, nutrients and gases

Question 4

What is diffusion of uncharged solutes?

Answer 4

movement due to a solute concentration difference - occurs because of random motion of solute molecules

Question 5

What is diffusion of charged solutes?

Answer 5

Electrolytes will also diffuse down a concentration gradient. - influenced by charges of particles around them = extra level of complexity around them

Question 6

What is Osmosis?

Answer 6

Special type of diffusion -flow of water across a membrane that is permeable to water but not to solutes -Higher water concentration to a region of lower water concentration (higher solute concentration) - Water ‘follows salt’

Question 7

What is oncotic or colloid pressure?

Answer 7

osmotic pressure generated by large molecules such as plasma proteins which cannot pass across the membrane

Question 8

What is Fick’s Law?

Answer 8

The factors governing the rate of diffusion across membranes Expressed as:

Question 9

What is the main difference between extracellular and intracellular fluid makeup?

Answer 9

Extracellular: protein is 0 Intracellular: Lots of potassium, but lower amounts of all other elements

Question 10

What is Molarity?

Answer 10

Concentration (g/L)/ Molecular weight

Question 11

What is Molality?

Answer 11

Moles of solute/Kg solvent

Question 12

What is Osmolarity?

Answer 12

Osmostic concentration: concentration of particles/L in solution and is independent of the size or weight of the particles = number particles/mole X concentration/L

Question 13

What is Osmolality?

Answer 13

Concentration of particles/Kg = number particles/mole X concentration/Kg

Question 14

True or false: Osmolarity approximates osmolality when solutions are dilute?

Answer 14

True

Question 15

What mostly determines osmolality/osmolarity concentrations?

Answer 15

Sodium ions

Question 16

What is isotonic?

Answer 16

concentration of solutes on both sides of the membrane is equal and NO water movement occurs -haemorrhage fluid loss is isotonic

Question 17

What is a hypertonic compartment or solution?

Answer 17

Higher concentration of solute outside (higher osmotic pressure) than inside the cell (lower osmotic pressure) *Net movement of water out of cell & cell shrinks & crenates* -Vomiting/diarrhea

Question 18

What is a hypotonic compartment or solution?

Answer 18

when the solution outside of the cells has a lower osmotic pressure than the cytoplasm of the cells, the solution is hypotonic with respect to the cells *water moves into cell & cell expands - haemolysis: cholera, haemorrhagic gastroenteritis

Question 19

What are teh 5 main parts of the cirulatory system?

Answer 19

heart: cardiac muscle contracts to pump blood around the body arterial system: distributes blood from the heart to the capillaries venous system: Acts as a reservoir for blood and returns blood to heart Lymphatic system: returns proteins and fluids back to blood

Question 20

What are the functions of the circulatory system?

Answer 20

1. exchange of substances with environment 2. transport of substrates and O2 to cells 3. Removal of metabolites and CO2 from cells 4. Thermoregulation 5. Immune cells and mediators

Question 21

What do the capillaries do?

Answer 21

They are the most key part = exchange of fluid ( nutrients and metabolic products) between blood and interstitial fluid

Question 22

What type of capillaries are these?

Answer 22

Continuous: - muscle - skin - lung - fat - connective tissue contain narrow junctions (clefts) & small, coated pits (caveolae) allowing hydrophobic molecules to pass

Question 23

what type of capillaries are these?

Answer 23

Fenestrated: - kidneys - intestines - endocrine glands - joints Contains pores or fenestrae - permeable to small molecules = Much larger gaps

Question 24

What type of capillaries are these?

Answer 24

Discontinuous: - bone marrow - liver - spleen = wide gaps between endothelial cells = permeable to large molecules

Question 25

What are Neural capillaries?

Answer 25

Virtually just water can get across this one - maintains blood brain barrier

Question 26

What are the three types of movement that allow substances to cross capillary walls?

Answer 26

1. Diffusion 2. Transcytosis and pinocytosis 3. Bulk flow via Starling’s Forces - hydrostatic and osmotic forces

Question 27

What are the functions of the lymphatic system?

Answer 27

1. controls blood and interstitial fluid volume 2. specific transport systems - absorption of fat from gut 3. turnover of extracellular matrix constituents 4. defence systems

Question 28

Where can lymph re-enter the lymphatic system?

Answer 28

1. Left side: head and neck thoracic cavity - upper limb (Main entrance) 2. Right side: head and neck thoracic cavity - upper limb

Question 29

What is Oedema?

Answer 29

Swelling of tissues due to excess fluid - generally due to the heart

Question 30

What is lymphoedema?

Answer 30

Lymphatic system is not working properly - lymphatic themselves are directly affected Primary cause = lack of sufficient lymphatic vessels - blocked or damaged lymphatics