skeleatl systems, Miss Howren, 12/10/13
Skeletal system of a prawn
Prawns unlike humans have a different type of skeleton which is made from chitlen. They have what you call a exoskeleton. This means that they have an external support structure. Prawns have a hard shell on the outside of their body which adds a layer of protection for them. However they can't survive without these shells. Without their shells all their flesh and muscle would be unprotected. It can also be easily removed and cracked by the force of other animals teeth and claws when wanting to eat them. Prawns just like snakes shed their shells when they get too big for them. Although this is a very clever way of regrowing their shell it does make prawns very venerable during this time. Some other animals that have a exoskeleton are crabs and insects.
Skeletal system of a worm
Just like most of the skeletons I'm talking about worms have a endoskeleton. However they are a bit different because they have no back bone. In addition worms do have bristles in-between each segment called setea. This enables them to move like they do. Worms have no limbs but 2 types of muscle, one that makes them long and skinny, the other making them fat.
Skeletal system of a cuttle fish
Cuttle fish have a endoskeleton just like us humans. However theirs are a bit different. Their skeleton are completely solid but light. Since cuttle fish are colour blind they need a strong and solid inside to protect them from forceful impacts. They also need to be buoyant. This means that they need a light body to help them float, and this is why there skeleton is made from calcium carbonate.
Skeletal system of a human
Humans have a endoskeleton. Our skeleton helps with supporting our body, protecting our organs and moving around. We have two parts to our skeleton, the axial skeleton and the appendicular skeleton. The axial skeleton is the bones in our body that protect our organs, it is made up of 80 bones and includes our skull, vertebral column, ribs and breastbone. Our appendicular skeleton helps us to move around and is made up of the majority of our bones, totalling 126. This includes our shoulder blades and the bones in our arms and legs. Our bones are living tissues, they are made from 3 main materials. These are:
1. Compact bone, which is the outer layer of your bone, this gives the bone it's strength. 2. Spongy bone, which is said to look like honeycomb. The gaps within the spongy bone are filled with bone marrow. 3. Bone marrow makes red blood cells and files the gaps within the spongy bone.
Our skeleton surprisingly enough loses bones as we get older. At birth we have 300 bones in out body. When were baby our skull is still forming so there are more bones in our skull. As we mature our little bones from together to make bigger bones. In the end making us only have 206 bones. Most living creatures have the same skeleton as us and to name a few, dogs, cats and horses.
Aim: The aim of this dissection was to reflect on are knowledge and put it to the test on dissecting a heart
materials: tweezers, apron, blade, scissors, wooden board and newspaper.
1. The heart is a red colour with white fat around it. it is very firm and slippery it has many arteries coming from the top of the heart and when were functional would bring blood in and out of the heart.
3. On the surface of the heart there are many small arteries called coronary arteries. These arteries carry nutrients and oxygen to the heart muscle. These are thin red lines that look like the roots from a tree. If these arteries were blocked it would stop blood flowing though them which would lead to...
4. There are four part to the heart the left and right atrium and the left and right ventricle, by these you can tell what side of the heart is what by ...
5. At the top of the heart there is a lot if fat and muscle. This muscle if quite squishy but still has some firmness. however as you get to bottom of the heart the muscle gets quite hard, although the left venatical is somewhat harder than the right. there is a lot of fat surrounding the heart, as you get further down there is less and less fat until you reach the very bottom where there is none. There are 4 major vessels at the top of the heart. these include the aorta which carry's blood to the brain and the rest of the body, the pulmonary artery which carry deoxygenated blood to the lungs to then be oxygenated then return back the heart. There is also the pulmonary vein which carry oxygenated blood to other organs and the vena cave which bring the blood which has run out of oxygen to go to the heart to go back to the lungs.
7. The aorta carries blood away from the left ventricle of the heart. This vessel has a thick wall. This wall needs to be thick so that the blood can be pushed out at a even rate. The aorta as I have said before carry's blood from the brain to the heart.
8. The vena cava is a vein that returns the blood from the body. the vena cave has a much thinner wall compered to the aorta. This is because the flow of the blood is different. the vena cava goes through the right ventricle.
10. Once we cut into the left ventricle we could see the left atrium as well as the left ventricle which had a very think muscular wall. there was also velves that looks that thin pieces of string they were a deeper red colour that the heart it's self. Some of the main velves we saw were that aortic veleve and the mitual velve. There job is to stop the blood going back aorta. the aorta is a firm pale pink artery that goes through the lest ventricle.