The heart is an organ that pumps blood around the body. To carry blood you have arteries, veins and capillaries.Arteries - Carries blood away from the heart at a high pressure. Arteries have a thick, elastic, muscular wall so they do not burst when carrying blood.
Veins - Veins carry blood back to the heart, they have a thinner wall than an artery as the blood they carry is not at such a high pressure. There are valves in a vein to prevent back flow of blood this is needed as veins do not have a lot of muscles like arteries.
Capillaries- They a small blood vessels that have thin cell walls to allow the passage of oxygen and nutrients into the body. These also connect the arteries and veins together.
Thursday, 24 May 2012
Thursday, 10 May 2012
Breaking Bones
Bones may be strong but they can snap with a knock in just the right place. When this happens there are three types of breakages:
Osteoporosis is a condition that some old people get where your bones are weakened and can break more easily.
 |
| Simple fracture |
- Simple fracture- this is when the bone breaks cleanly.
- Greenstick fracture- where the bone doesn't break completely.
- Compound fracture- where the bone comes all the way out of the skin and muscles. (This is by far the most painful)
Osteoporosis is a condition that some old people get where your bones are weakened and can break more easily.
The Circulatory Systems
There are two types of circulatory systems, a single circulatory system and a double circulatory system.
Single Circulatory System
The single circulatory system is found in organisms like insects and fish. The blood flows around the body in one single circuit. This means in the heart there are two chambers, for the deoxygenated blood. When the blood leaves the heart it goes to the respiratory system where the blood gets oxidised before getting sent round the body, the blood then is sent back to the heart deoxyenated. The blood is pumped around the body at a low pressure and is transported slowly.(Image from http://home.sandiego.edu)
Double Circulatory System
The double circulatory system is found in most mammals. This means that there are two circulatory systems one to the body and one to the lungs, these to circulatory systems need four sections of the heart so the blood can pump round the body. The deoxygenated blood form the body enters the heart, the heart then pumps this blood to the lungs. From the lungs the now oxygenated blood goes back to the heart where it is then pumped round the body.(Image from http://revisionworld.co.uk)
Single Circulatory System
The single circulatory system is found in organisms like insects and fish. The blood flows around the body in one single circuit. This means in the heart there are two chambers, for the deoxygenated blood. When the blood leaves the heart it goes to the respiratory system where the blood gets oxidised before getting sent round the body, the blood then is sent back to the heart deoxyenated. The blood is pumped around the body at a low pressure and is transported slowly.(Image from http://home.sandiego.edu)Double Circulatory System
The double circulatory system is found in most mammals. This means that there are two circulatory systems one to the body and one to the lungs, these to circulatory systems need four sections of the heart so the blood can pump round the body. The deoxygenated blood form the body enters the heart, the heart then pumps this blood to the lungs. From the lungs the now oxygenated blood goes back to the heart where it is then pumped round the body.(Image from http://revisionworld.co.uk)
Skeletons
There are two types of skeletons:
Exoskeleton - This is a skeleton on the outside of the body (external)
Endoskeleton - The skeleton is on the inside of the body (internal), humans have an endoskeleton
However some organisms like worms have no skeletons and elasmobranch (sharks and eels) have no bones, their skeletons are made up of cartilage so their body's are very flexible.
There are many benefits to having a internal skeletons:
Exoskeleton - This is a skeleton on the outside of the body (external)However some organisms like worms have no skeletons and elasmobranch (sharks and eels) have no bones, their skeletons are made up of cartilage so their body's are very flexible.
There are many benefits to having a internal skeletons:
- They provide a framework and shape for the body.( So you don't flop on the floor)
- They will grow with the body.
- It is easy to attach muscles to the skeleton.
- the skeleton has joints that allow you to be flexible. (so you aren't a plank)
In an external skeleton the skeleton is made from chitin, this is a type of bone that does not grow with the body. This means animals with an exoskeleton shed there outer skeleton in order to create a bigger one that grows in a couple of days depending on the creature.
This is a link to show you what happens when a crab grows.
Friday, 27 April 2012
In this blog we will make GCSE Biology easier to understand. Each week we will be posting new information about the subject, so if you are doing GCSE Biology or you just want to get up to date on your Biology then look each week as we explain different topics.
We are two students at school making this blog for a science project, please ask any questions and we will try and answer them to the best our ability.
We are two students at school making this blog for a science project, please ask any questions and we will try and answer them to the best our ability.
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