Week 1 Flashcards
Intracellular fluid
- AKA ICF
- Fluid within cells
Extracellular fluid
- AKA ECF
- fluid outside the cells
- precisely regulated fluid
- internal environment of the body
Normal core body temperature
37 degrees C
Normal pH range in the body
7.35 - 7.45
Normal potassium [K+] range in body
3.5-5.0mmol/L
Normal calcium [Ca+] range in body
2.2-2.7mmol/L
Normal blood glucose range in body
70-100 mg/dl
Normal blood volume in body
5 L
Normal mean arterial pressure in body
93 mmHg
Normal arterial oxygen levels
75-100 mmHg
Normal arterial carbon dioxide levels
34-45mmHg
Consequences of homeostatic failure
- values of physiological parameters drift outside normal ranges
- disease, changes throughout body, death
Types of homeostatic feedback control
negative feedback and positive feedback
Negative feedback
- Reverses effect on original stimulus
- Maintains conditions that require frequent monitoring; long term
- temperature regulation
Positive feedback
- Amplifies effect of original stimulus
- Associated with infrequent, short term processes
- minor role
- blood clotting
Components of a homeostatic feedback system
- stimulus produces change in variable
- change detected by receptor
- information sent by receptor to control centre
- control centre compares information from receptor with monitored value with acceptable range. Information sent to effector
- Response of effector returns monitored value within limits of normal range
Matter
Anything that occupies space and has mass
What is matter composed of
Elements
Elements are…
- unique substances
- composed of atoms
- can not be broken down into simpler substances by chemical means
- 92 naturally occurring
How are elements arranged in the periodic table?
By their atomic numbers
Major chemical elements in the body
- oxygen (96%)
- Carbon (65%)
- Hydrogen (9.5%)
- Nitrogen (3.2%)
Significance of oxygen in body
- part of water and many organic molecules
- used to generate ATP
Significance of carbon in body
- forms backbone chains and rings of all organic molecules, carbohydrates, lipid, proteins and nucleic acids (DNA, RNA)
Significance of hydrogen in body
- constituent of water and most organic molecules
- ionised form makes body fluids more acidic
Nitrogen
- component of all proteins and nucleic acids
Lesser chemical elements in the body
- calcium (1.5%)
- phosphorus (1%)
- potassium (0.35%)
- sulfur (0.25%)
- sodium (0.2%)
- chlorine (0.2%)
- magnesium (0.1%)
- iron (0.005%)
Significance of calcium in body
- hardness of bones and teeth
- ionised form: blood clotting
- release of some hormones
- muscle contractions
Significance of phosphorus in body
- component of nucleic acids and ATP
- required for normal tooth and bone structure
Significance of potassium in body
- ionised form most plentiful cation in intracellular fluid
- needed to generate action potentials
Significance of sodium in body
- ionised form most plentiful cation in extracellular fluid
- needed to generate action potentials
Significance of chlorine in body
- ionised form most plentiful anion in extracellular fluid
- maintaining water balance
Significance of sulphur in body
component of some vitamins and many proteins
Significance of of magnesium in body
ionised form needed for action of many enzymes
Significance of iron in body
ionised forms part of haemoglobin and some enzymes
Trace elements in body
Total 0.4%
aluminum, boron, chromium, cobalt, copper, fluorine, iodine, manganese, molybdenum, selenium, tin, vanadium, zinc
Atoms
smallest component of an element that retains the properties of that element. Unique properties are due to the number of protons, neutrons and electrons
Atom structure
Nucleus: protons and neutrons
Electron cloud/shells orbiting
subatomic particles
proton: +1, 1amu, nucleus
Neutron: 0, 1ami, nucleus
Electron: -1, 1/1800amu, orbitals
mass of protons and neutrons
- approx. same mass
- 1.67 × 10−24 grams
mass of electrons
9.11 x 10-28 grams
Atomic number
- determined by number of protons an atom has
- how the periodic table is organised
Isotopes
Different atomic forms of the same element, vary only in number of neutrons (same protons #)
Electron and reactivity
- outermost shell determines reactivity of an atom
- outer shell full: un-reactive
- outer shell incomplete: reactive
Ions
- atom that loses or gains an electron
Cations
- atoms that lose electrons
- net positive charge
Anions
- atoms that gain electrons
- net negative charge
Free radicals
- having unpaired electron in outermost shell
- unstable
- highly reactive
- destructive to nearby molecules
Valency
capacity of an atom to form chemical bonds with other atoms and molecules, determined by number of electrons in the outer shell
Molecules
2 or more atoms united via a covalent bond
Compounds
- 2 or more different elements chemically bonded in a fixed proportion
Organic compounds
- contain carbon
- characteristics of living organisms
Inorganic compounds
- not of biological origin
- don’t contain carbon, with exceptions (e.g. oxides of carbon)
- includes water, oxygen, nitrogen, carbon dioxide, salts, acids, bases: essential for life
