Scientific Principles

Question 1

What are 5 bodily requirements?

Answer 1

Food
Water
Heat
Pressure
Oxygen

Question 2

What are characteristics of life?

Answer 2

Digestion
Respiration
Absorption
Growth
Responsiveness
Assimilation
Circulation
Excretion
Reproduction
Movement

Question 3

What is an element?

Answer 3

Pure substance that can be broken down no further. One type of atom. Eg Fe H C O N

Question 4

What is a compound?

Answer 4

Pure substance that can be broken down no further and made with 2 or more elements. NaCl H2O

Question 5

What are atoms?

Answer 5

Smallest building blocks of life. Made of protons, neutrons and electrons

Question 6

What are molecules?

Answer 6

Combining of atoms

Question 7

What are ions?

Answer 7

When atom looses or gains electons eg Na+ Cl-

Question 8

What are 3 main types of bonding of atoms?

Answer 8

Covalent - sharing electrons
Polar - aka hydrogen bonding. DNAhas this. weak bond due to electrical charge
Ionic - doesn’t share or transfer electrons

Question 9

What are electrolytes?

Answer 9

when molecules that are ionically bonded dissolve in water

Question 10

What are electrolytes important for?

Answer 10

1. Essential minerals
2. Control process of osmosis
3. Help maintain acid-base balance for normal cellular activity

Question 11

What % of body weight is water?

Answer 11

60%.

40% intracellular fluid
20% extracellular fluid - then 80% interstitial, 20% intravascular

Question 12

do babies have the same water percentage as adults?

Answer 12

No, babies have 70-83% water as newborn (compared to 60%)

Question 13

What does intracellular fluid consist of?

Answer 13

Mainly water, with some dissolved ions, small molecules and larger water-soluble molecules.

Question 14

What dose extracellular fluid consist of?

Answer 14

Solution of water and Na, K, Ca, Cl and hydrogen carbonate.

pH 7.4

low protein compared to ICF.

Question 15

what are 3 sub compartments of extracellular fluid?

Answer 15

1. Interstitial fluid - about 75% of ECF, surrounds cells, does not circulate
2. plasma - circulates, nearly 25% of ECF
3. Transcellular fluid - just outside cells, small amount (1-2 litres in adult) e.g. mucus, digestive juices, CSF, aquesou humour, joints and urines

Question 16

What is fluid shift?

Answer 16

Movement of fluids across semipermeable membranes.

Controlled by hydrostatic pressure gradient and osmotic pressure gradient.

e.g. increased BP forces fluid and solutesout of capillaries at arterial end = hydrostatic pressure. But osmotic pressure moves fluid and solutes back in at venous end of capillaries

Question 17

What are functions of body fluid?

Answer 17

1. Major component of transport system.
2. Regulates temperature
3. Provides optimum medium for cells to function
4. provides lubrication for organs and passageways (e.g. oesophagus)
5. lubricant for joints + eyes
6. breaks down food in gut
7. protects foetus.

Question 18

What is the effect of water deficiency (aka dehydration) on the body?

Answer 18

• low BP
• poor clotting
• renal failure
• constipation
• higher infection risk
• electrolyte imbalance

Question 19

What are electrolytes important for in the body?

Answer 19

• Forming essential minerals
• Controlling osmosis
• Maintaining acid-base balance
• Regulating movement of fluids between compartments
• Essential for neurones

Question 20

Which 3 hormones regulate electrolytes?

Answer 20

1. ADH - antidiuretic hormone
   Produced in hypothalamus
2. Aldosterone - produced by adrenal glands
   increases reabsorption of Na and H20 therefore increases BP and blood volume
3. Atrial Natiuretic Peptide - secreted by heart cells - powerful vasodilator Relased by myocytes if high BP and then will Lowe rBP.