Skeletons And Their Different Forms

Exoskeletons-  Exoskeltons is the structure of the skeleton but on the outside of the body. It is a hard structured shell,  exoskeletons are usually found on insects, crustaceans and mollusks. The advantages of an exoskeleton is that it is used for protection and to help against predators. It also prevents the creature from drying up. The exoskeleton contains chitin and when calcium carbonate is added, the exoskeleton will grow in strength and hardness.
Internal skeletons-  Internal skeletons provide a framework and shape for the body, it grows with the body, easy to attach muscles to and also they have joints which is important for flexibility. The internal skeleton is made mostly of bones and cartilage. Humans and most animals have these structures, but animals like sharks internal skeletons are made completely of cartilage.
Long bones- long bones are hollow, they weigh less and are much stronger than hollow bones. The top of the bone is covered in slippery and  hard cartilage to lubricate the movement against other bones. The shaft contains bone marrow and blood vessels.
Growing bones- All the bones in an embryo are made from soft and flexible cartilage. During growth the cartilage is replaced by calcium and phospherous salts (this makes the bone hard). This is commonly known as ossification. Children have cartilage in their bones because they're still growing. Adults only hace cartilage at the ends of their bones. whether a person is still growing or not can be determined by the amount of cartilage is present.
Broken bones- Broken bones can be defined by three ways;
A simple fracture- is when the bone breaks
A greenstick fracture- is when the bone doesnt break completely.
A compound fracture- is when the broken bone breaks through the muscle and skin.
If someone has a fracture is best not to move them especially if it is a spinal injury, as it could make it worse. Bones can repair and regrow themselves.

The heart and its functions

The hearts main function is to pump blood around the body ensuring all cells get the oxygen and glucose they need which is carried around in the blood stream. The right side of the heart receives de-oxygenated blood from the tissues around the body.t This blood is then pumped at high pressure from the right ventricle to the lung through the pulmonary artery. The left side of the heart receives oxygenated blood from the lungs via the pulmonary veins and into the left atrium. This blood then travels to the left ventricle and is then under great pressure pushed from the aorta, to ensure oxygenated blood gets to all parts of the body.

The coronary artery- this supplies the heart with oxygen and glucose.

The aorta- This carries oxygenated blood from the heart to the rest of the body.

The vena cava- this carries de-oxygenated blood from parts of the body back to the heart.

the pulmonary artery- this carries de-oxygenated blood from the heart to the lungs.

The differences between veins and arteries in the cardiac system is the direction of blood flow, the arteries carry oxygenated blood away from the heart and veins de-oxygenated blood (apart from the pulmonary vein) carry it towards the heart.

The pulmonary vein- carries oxygenated blood from the lungs to the heart.

The heart is a made up of powerful which relax and contracts to pump the blood around the body. It needs a constant supply of oxygen and glucose, this ensures it has enough energy for respiration. As the heart never gets tired or needs rest, it demands a high requirement for energy. The hearts consists of five main areas; 

The cardiac cycle is the sequence that happens between heart beats. When the heart relaxed and the blood enters both atria from the veins. At this point the atrioventricular valves are open. The atria then contract to push the blood to the ventricles. The ventricles then contract,l pushing all the blood to the arteries. Then the semilunar valves open to allow this as the atrioventricular valves close.

The sinoatrial node (SAN) is the pacemaker of the heart. It is a tiny area of the heart which is specialised cardiac muscle in the upper wall of the right atrium, The fibres, rhythmically, contract 70 times each minute. After each contraction the impulse travels through the atrial cardiac muscles, causing the both atriums to contract. This then stimulates the atrioventricular node (AVN) this is located in the bottom of the atria and then sends impulses causing the ventricles to contract.

Artificial pace makers are devices that fix a heart that is damaged. Even though it fixes damaged heart if it is too severe then a donor heart will have to replace it.
A artificial pacemaker is a device that uses electrical impulses to regulate the hearts rhythm.An internal pacemaker is one in which the electrodes to the heart, the electronic circuitry, and the power supply are all implanted internally, within the body. Although there are different types of pacemakers, all are designed to treat a heart rate that is too slow. Pacemakers may function continuously and stimulate the heart at a fixed rate, or they may function at an increased rate during exercise. A pacemaker can also be programmed to detect an overly long pause between heartbeats and then stimulate the heart.

About Us x

Hello, we are students which attend Warblington Secondary School in which we are in Year 10.
 In this blog we will be displaying a vast range of GCSE Biology work including information on very interesting subjects such as; the skeletal system and other facts about the human body.
 Please take your time to read through our blog, we hope you find everything helpful and necessary.

Love Tilly and Beth x