Additional Biology - Edexcel

Components of the Blood

PLASMA -  Carries nutrients, hormones and carbon dioxide. Parts of a cell, does not have a nuclei.

RED BLOOD CELL - Carries haemaglobin, haemaglobin combines with oxygen this makes oxyhaemaglobin. No nucleus, as need more room for oxygen. Biconcave disk to give a large surface area to volume ration for absorbtion of oxygen.

WHITE BLOOD CELL - Have antibodies made of protiens to protect from bacteria. Some antibodies bind to bacteria and destroy them. Other white cells surround and destroy foreign cells in the body. White blood cells HAVE a nucleus.

THE BLOOD MAY BE A LIQUID BUT IT IS CALLED AN ORGAN THIS IS BECAUSE THE CELLS ARE ALL SPECIALISED TO DO A SIMILAR FUNCTION.

HEART- The heart is a muscle. It pumps deoxgenated blood into the right atrium through the Vena Cava, this is then pushed into the right atrium The right atrium then contracts squeezing the blood into the right ventricle, when the ventricle contracts the blood is pushed out through the Pulmonary Artery which delivers the blood to the lungs. The lungs oxygenate the blood, which is then taken through capillaries and back through the pulmonary vein into the left atrium, the atrium contracts pushing blood into the left ventricle. When the left ventricle contracts blood is pushed through the Aorta the artery leading to the rest of the body. The oxygenatd blood will diffuse through cappilaries into cells; ensuring cells are oxygenated.

Blood Vessels

 TYPES -The body has three types of blood vessels: Ateries, Veins and Capillaries.
Arteries are used to send blood from the heart. Arteries have a thick muscle wall with a thin lumen (space where blood flows). This is because ateries need to have a high pressure so oxygenated blood can reach parts of the body quickly and efficiently. However, the thick wall of the artery would make it difficult for oxygen to diffuse into cells. Arteries…