B2.3 Common Systems Flashcards
Why are there gaps in the fossil record?
- Soft tissue decays
- Some hard tissue is destroyed before a fossil can form
- Some fossils have not yet been found
What is the common basic limb structure through time in vertebrates?
The Pentadactyl limb.
Name three species that have the pentadactyl limb.
Many answers possible, including human, whale, horse, bird, bat, frog and lizard
What is a meristem?
An area in a plant where cells divide by mitosis
What is elongation?
An area where cells get longer in a plant.
What is differentiation?
When stem cells differentiate into specialised cells for their job.
What is the composition of blood?
55% plasma
45% red blood cells
What red pigment can combine reversibly with oxygen to transport it around the body?
Haemoglobin, oxyhemoglobin when it has combined.
What is a fossil?
The preserved traces or remains of an organism that lived thousands if years ago.
What is the function of our heart?
To pump oxygenated blood around our body
In order, through what does a red blood cell travel through on its way through the heart?
Vena Cava, right atrium, artio-ventricular valve, right ventricle, semi-lunar valve, pulmonary artery, pulmonary vein, left ventricle, atrio-ventricular valve, left ventricle, semi-lunar valve, aorta
Why is the muscle thicker on the left side of the heart than on the right side of the heart?
The left side needs to pump the blood around the whole body, not just to the lungs
What is an artery?
A blood vessel with a thick, muscular wall that carries oxygenated blood away from the heart.
What is a Vein?
A blood vessel with a thin, muscular wall that carries deoxygenated blood to the heart.
What is a capillary?
A blood vessel with a one cell thick wall that carries blood to where diffusion of substances needs to happen.
What is an organ system?
A group of organs working together for a purpose.
What does digestion do?
Breaks down large insoluble molecules into smaller soluble molecules so that our bodies can use it.
Which organs are a part of the alimentary canal (where the food travels)?
Mouth, Oesophagus, stomach, small intestine, large intestine, anus.
Where is bile stored, made and found?
Bile is made in the liver, stored in the gall bladder and released into the small intestine.
What is the process where a bolus of food is pushed down the Oesophagus?
Peristalsis
What is a bolus?
A small ball of food that can travel down you Oesophagus.
How is the acidic content of the stomach neutralised in the small intestine?
With Bile.
What enzymes are used to digest Carbohydrates, Proteins and Fats?
Carbohydrates : Amylase
Proteins : Protease
Fats: Lipase
What do Carbohydrates, Proteins and fats break down into?
Carbohydrates : Simple sugars
Proteins : Amino Acids
Fats : Fatty acids and glycerol
What does Bile do to fats?
Emulsifies them (breaks them down into tiny droplets to give them a larger surface area to volume ratio)
What are villi?
Folds in the lining of the small intestine to increase surface area for the absorption of food?
What is inside Villi and what are their purpose?
Blood capillaries, which quickly take absorbed food away to allow more absorption to take place.
What is Coeliac Disease?
A disease where there villi are lost.
What are probiotics?
Foods that contain the bacteria Lactobacillus which produce lactic acid in the gut?
What are plant sterol esters?
Oily substances found in plants, which lower the level of cholesterol in your blood.
What are prebiotics?
Substances that you body cannot digest and act as food for beneficial bacteria in your gut.
