Senior Science Flashcards
List a few chemicals used in everyday life (3)
Cleaner - emulsifies
Lubricants - reduces friction
Cosmetics - slows water loss
What is the tyndall effect?
Light that is visible passing through a…colloid/suspension
List mixtures according to particle size:
Small - solutions
Medium - colloids
Large - suspensions
Provide an example of each mixture (solution, colloid, suspension)
Solution - soft drink
Colloid - milk
Suspension - flour suspended in water
What is a solution?
Dissolved particles, uniformly distributed
What is a colloid?
Particles that are suspended, do not filter but settle
What is a suspension?
Particles that separate over time, can be filtered
List 4 types of colloids
Emulsions
Foam
Sol/gel
Aerosol
What is an emulsifier?
Substance that allows dispersion of liquids
Define surface tension
Forces between molecules in a liquid, pulling them inward
Define miniscus
Shape that the surface of a liquid takes in a tube
How does a surfactant work?
Where a molecule dissolves into an oil substance, REDUCING SURFACE TENSION
Define the purpose of an emulsion
Dispersion of droplets of one liquid into another which are not soluble
Define biodegradable
Substance that can be broken down by living organisms
Why is skin classified as an organ?
Because it contains a minimum of two tissues working together
Where are new cells made?
Low layerm of epidermis
Functions of the skin?
- Heat regulation
- Protection
- Excretion
- Sensation
- Immune response
What is the purpose of micro-flora on the skin?
Mutualism occurs as micro-flora break down sebum into fatty acids to maintain the slight acidity of the skin
What are the 2 most commonly used solvents and why?
Water - due to polarity of water allows greater attraction and dissolving
Ethanol: It contains carbon atoms and is ‘organic’
For a drug to be effective it must…
- Reach target at correct doasage
- treat
- last long to take effect
- only affect tissues designed for
- have few side effects
What is the pH of the skin, mouth, stomach and small intestine?
Skin: 5.5
Mouth: 8
Stomach: 3
Small Intestine: 9
What are two types of tablets?
Enteric-coated
Slow-release eg. Osmotic pump
What is the purpose of an enteric-coated tablet?
Remains intact within the stomach, released in small intestine to be absorbed into bloodstream
Define vitamins
Organic molucules needed for: growth, reproduction, maintenance, that speed up reactions of enzymes. Either FAT or WATER soluble
Difference between FAT/WATER soluble vitamins?
Fat - persist within the body
Water - readily excreted
List 2 biomedical devices and their use/material
Pacemakers: Control beating of heart - silicone plastic
Plates/pins/screws: Hold bones together - metal
What are the tricuspid valves?
Valves that prevent back-flow of blood
What is diastole and systole?
Diastole: Ventricles relax
Systole: Ventricles contract
What are the 5 sections of an ECG?
PQRST
List 2 types of replaceable valves
Bi-leaflet 1970’s - blood clotting
Allograft 1960’s - dead people
Negative consequences of atherosclerosis
Obstruction of blood flow
Can cause blood clots
Weakens walls of arteries
List 2 materials used in boimaterials
Plastic (UHMWPE, silicone)
Metals (Super alloys)
What are 4 types of movable joints?
Hinge
Ball-n-socket
Gliding
Pivot
What is a heart-lung machine?
Maintains functions of heart/lungs while either or both cannot work
Compare minimally/non-invasive
Minimally: Cheap, longer recovery
Non: Cheap, painless, less effective
List 2 types of minimally invasive techniques
x-rays- x-rays sent through body produce image of bones
Keyhole- Instruments fed through vessels to carry out surgery of tissues/organs
Process of info transfer
Code -> message -> transmission -> decoder
Define diode
Type of decoder
3 classification systems of telecommunications
verbal?
electronic?
distance..?
List the 4 main types of EMS waves giving an example for each
Visible light - optical fibres
Infra-red - thermal imaging
Microwaves - satellites for mobile networks
Radio waves - TV, radio
Advantages of using EMS as a form of communication
Light speed
Travels in a straight line
Reflected - signals can be deliberately bounced off the ionosphere
Define geostationary satellites
“same time as Earth” travels at speeds in the same position relative to Earth - to ensure same position from Earths satellite dishes
Define scanners
Narrow beam of light scans, scanning into a series of thin lines
Define total internal reflection
When incident angle in a slow medium is greater than critical angle
Advantages of optical fibres
multiplex, large bandwidth, secure, no interference
CNS?
Brain
Spinal cord
Nerves
3 types of neurones (sim)
sensory
interneuron
motor
Sensory neuron
From body
Interneuron
Messages between sensory/motor
Motor neuron
From CNS to muscles/glands
Sense organs?
Detect stimuli from inside/outside body. They detect specific stimuli
Effectors? Examples
Organs that act to motor neuron signals (glands/effectors)
Reflex arc?
Receptors receive stimuli that requires immediate response to prevent harm
What 4 things does the circulatory system transport?
Nutrients, waste, oxygen, hormones
3 types of blood vessels?
Arteries, capillaries, veins
