Homeostasis and body fluids Flashcards
(22 cards)
homeostasis
the control or stabilisation of the internal environment
conformers
‘primitive’ organisms that are restricted to constant environments
regulators
able to control internal environments
internal environment
extracellular fluid
what percentage of body water is found in the extracellular fluid?
33%
what makes up the extracellular fluid?
- plasma
- interstitial fluid
- trancellular fluid
what factors can affect the internal environment?
- gasses (O2, CO2,)
- ions (NA, K, Ca)
- glucose
- blood pH
- temperature
what are the different feedback systems?
- negative feedback
- positive feedback
negative feedback
effector system opposes the initiating stimuli (eg: blood pressure)
positive feedback
effector systemreinforces or amplifies the initiating stimuli (eg: blood clotting, oxytocin+ labour contractions)
what are the characteristics of negative feedback?
- a set point for the physiological parameter being regulated
- a sensor to monitor the regulated variable
- the ability to detect any error between the sensor and the set point by a comparator
- an effector to bring about a compensatory change
covalent bond
- sharing of electrons
- strong stable bond
hydrogen bonds
attractive force (often forms between water molecules
ionic bonds
- donated or received electrons
- weaker more unstable bonds
electrolytes
ionic compounds dissolved in water (conduct electricity, osmotic pressure, buffers)
functions of water
- Temperature regulation: evaporation from skin and lungs
- Protective cushion: amniotic fluid, CSF
- Lubricant: synovial fluid
- Reactant: hydrolysis reactions eg. starch breakdown
- Solvent: eg. dissolves solutes salts (ions) and nutrients
- Transport: medium for nutrient delivery/waste removal via plasma
what are significant properties of water?
- charged dipole (good at dissolving things)
- ability to form H-bonds (high boiling point, latent heat, high surface tension)
- ## high specific heat capacity (absorb and release large quantities of heat without large change in temp)
what are the concentrations of Na in the plasma, interstitial fluid and intracellular fluid?
- plasma: 142
- interstitial: 139
- intracellular: 14
what are the concentrations of K in the plasma, interstitial fluid and intracellular fluid?
- plasma: 4.2
- interstitial: 4.0
- intracellular: 140
what are the concentrations of Ca2+ in the plasma, interstitial fluid and intracellular fluid?
- plasma: 1.3
- interstitial: 1.2
- intracellular: 0
what are the concentrations of Cl- in the plasma, interstitial fluid and intracellular fluid?
- plasma: 106
- interstitial: 108
- intracellular: 4
what are the concentrations of protein in the plasma, interstitial fluid and intracellular fluid?
- plasma: 1.2
- interstitial: 0.2
- intracellular: 4
