Topic 3 Common systems
Fossils
Preserved traces or remains of an organism that lived a long time ago
Fossil record
The collection of fossils identified from different periods of time. Can be
interpreted to form a hypothesis about the evolution of life on Earth
Evolution
The development of new species over time through a process of natural
selection
Pentadactyl (H)
Five fingered
Growth
Increase in size, length, mass and cell number
Percentile
Value of a variable where a certain percentage of observations fall.
Eg 20th percentile is 20% of the data points are the same or lower
Elongation
Getting longer
Differentiate
Specialise – develop into different kinds (eg in cells that can become
nerve, muscle or bone cells)
Stem cells
An unspecialised cell that can divide to produce more stem cells or
different types of specialised cells
Blood
Plasma
Liquid component of the blood that carries all the suspended cells and
dissolved substances
Red blood cells
Biconcave discs containing haemoglobin. Gives blood it’s red colour
and carry oxygen around the body to its tissues
White blood cells
Several different types of cells that are part of the body’s defence
system against disease
Platelets
Cell fragments that are important for the clotting of blood
Haemoglobin
The red iron-containing pigment found in red blood cells
Tissue
A group of specialised cells that all carry out the same function
Antibodies
Proteins that bond to microorganisms that cause disease (pathogens)
and destroy them
Heart & circulation
Organ
A group of differentiated tissues working together to carry out a
particular function
Deoxygenated
Without oxygen
Oxygenated
Septum
With oxygen
Thin membrane separates the two sides of the heart
Vena cava
A major vein leading to the heart
Right atrium
One of the four chambers of the heart that receives blood from the
vena cava
Valves
Flaps of tissue in the heart that stop the blood flowing backwards
Right ventricle
One of the four chambers of the heart. Receives blood form the right
atrium and pumps it to the pulmonary artery
Pulmonary artery
Arteries that carry deoxygenated blood from th right ventricle to the
lungs
Left atrium
One of the four chambers of the heart. Receives blood from the
pulmonary vein
Pulmonary vein
Veins that carry blood from the lungs back to the left atrium
Left ventricle
One of the four chambers of the heart. Receives blood from the left
atrium and pumps it to the aorta
aorta
Major artery leading away from the heart
Blood vessels
Tube that contains blood as it flows around the body
Arteries
Vessels that transport blood away form the heart
Capillaries
Tiny blood vessels with thin walls to allow diffusion of substances in &
out of the blood
Veins
Vessels that transport blood back to the heart
Organ systems
Group of organs working together to carry out a particular function in
the body
Circulatory system
Organ system involving heart and blood vessels which oxygenates the
blood and moves it around the body
Digestion
Digestion
Break down of large insoluble food molecules into small soluble food
molecules
Digestive system
System of organs that together digest food into the body
Alimentary canal
Muscular tube that runs from the mouth to the anus (includes
oesophagus, stomach, small & large intestines.
Enzymes
A protein molecule made by living cells that speeds up the rate of a
reaction
Bolus
A ball shapes mass of chewed food
Saliva
Lubricates food & makes it easier to swallow. Also contains amylase
which begins digestion of carbohydrates
Oesophagus
Muscular tube between the mouth & the stomach
Peristalsis
The waves of muscular contraction that move food along the
alimentary canal
Stomach
Organ that makes acid and some enzymes
Small intestine
Organ where digestion is completed and nutrients are absorbed
Villi
Finger like folds of the small intestine’s lining. Greatly increase the
surface area for absorption (diffusion) of digested food products into
the blood
Pancreas
Organ that makes digestive enzymes and secretes them into the
small intestine
Large intestine
Organ that absorbs water from digested material
Faeces
Undigested, waster material
Liver
Organ that has a range of functions, including secreting bile
Bile
Alkaline substance made by the gall bladder and helps with digestion
of fats
Gall bladder (H)
Organ that stores bile made by the liver. Releases bile into the small
intestine through the bile duct.
Breaking down food
Carbohydrates
Compound made up of carbon, hydrogen & oxygen. Used for energy by
organisms
Proteins
A polymer made up of amino acids. Contains C, H, O, N> genes carry
the instructions for making these
Fats
Chemicals that are used t store energy In organisms
Sugars
A group of compounds formed from carbon, hydrogen and oxygen.
Needed for respiration
Starch
A carbohydrate. Made by joining together thousand of glucose molecules
Carbohydrase
Enzymes that catalyse the breakdown of starch into simple sugars
amylase
A carbohydrase enzyme that breaks down starch into simple sugars
Protease
Enzyme that digests proteins into amino acids
Amino acids
A small molecule that is the building block of proteins
Pepsin
Example of a protease enzyme found in the stomach
Lipase
Enzyme that digests fats into fatty acids & glycerol
Fatty acids
Part of the structure of a fat or oil
Emulsifies (H)
Turn into an emulsion (mixture where particles of one liquid are
suspended in another
Biotics
Functional foods
Foods not eaten for nutritional value but claim to make you healthier
Probiotics
Foods containing live bacteria that produce lactic acid in the gut. May
improve the health of your digestive system
Lactobacillus
Example of a probiotic bacteria
Biffidobaceria
Example of a probiotic bacteria
Plant stanol esters
oily substances found in plants that appear to lower blood cholestorel
levels in people
A fat which is made in the liver and carries around the body I the
blood. High levels are linked to heart disease.
Cholesterol
Prebiotics
Substances that cannot be digested (by human digestive enzymes)
but act as food for probacteria in the intestine
Oligosaccharides
A type of carbohydrate that is a common prebiotic