[BIO] Chapter 7 - Transport in Humans

© Hee Xin Wei (Copyrighted) Topic 7: Transport in Humans

Chapter Analysis FOCUS EXAM WEIGHTAGE •commonly tested in both MCQ and structured •tested every year in the past 5 years •Constitute to around 9% in Paper 2 in the past 5 years •Heavy content •Knowledge on circulation system is linked to other chapters

Components of blood Blood group Key Concept

components and roles of blood (1) role of blood in transport Cells 45% Plasma 55% 1.90% water: essential in transporting blood cells and dissolved substances 2.10% a mixture of dissolved substances: •Soluble plasma proteins such as fibrinogen, prothrombin and antibodies. Fibrinogen and prothrombin play an important part in the clotting of blood. These proteins are made in the lever. Antibodies help to fight diseases. •Dissolved mineral salts, for example, hydrogencarbonates, chlorides, sulfates and phosphates of calcium, sodium and potassium. All these occur as ions in the plasma. Calcium is essential for blood clotting. •Food substances, for example, glucose, amino acids, fats and vitamins. •Excretory products, for example, urea, uric acid and creatinine. Carbon dioxide is present as hydrogencarbonate ions. •Hormones, for example, insulin. •Vitamins •red blood cells •white blood cells •platelets

red blood cells 1.The oxygen diffuse from the lung into the blood and bind reversibly with haemoglobin in red blood cells to form oxyhaemoglobin. 2.When blood is transported to oxygen-poor respiring tissues, oxyhaemoglobin releases its oxygen which then diffuses into tissue cells. (more will be discussed in the respiration chapter) Adaptation of RBC to its function: •Contains haemoglobin, an iron-containing protein which is able to bind reversibly with oxygen, which enables red blood cells to transport oxygen from the lungs to other body parts •Mature red blood cells do not possess a nucleus, enabling it to carry more haemoglobin and thus more oxygen. •Flattened, biconcave shape which increasing the surface area to volume ratio for faster diffusion of oxygen •Flexibility to turn bell-shaped in order to pass through the narrow lumen of the capillaries (2) role of blood in transporting oxygen

white blood cells IMMUNE FUNCTIONS (i)Phagocytes have lobed nuclei and granular cytoplasm. They engulf and digest foreign particles such as bacteria (phagocytosis) (ii)Lymphocytes have a large rounded nucleus and a small amount of cytoplasm. They produce antibodies to protect the body from pathogens. TISSUE REJECTIONS 1.Tissue rejection occurs when the transplanted tissue is not accepted by the body of the transplant recipient. 2.This because the tissues of the transplanted organ are treated as foreign bodies by the recipient’s immune system and are attacked by phagocytes. 3.Prevention of tissue rejection: (a)Required tissue can be transplanted from genetically-similar donors (family members) (b)Tissue can be transplanted from one part of the body to