Transport in Humans The circulatory system

Specification ( ) 2.49understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell 2.50understand the need for a transport system in multicellular organisms 2.57describe the composition of the blood: red blood cells, white blood cells, platelets and plasma 2.58understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy 2.59explain how adaptations of red blood cells, including shape, structure and the presence of haemoglobin, make them suitable for the transport of oxygen

Specification ( ) 2.60describe how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen 2.61understand that vaccination results in the manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity 2.62understand that platelets are involved in blood clotting, which prevents blood loss and the entry of micro-organisms

Specification ( ) 2.63describe the structure of the heart and how it functions 2.64explain how the heart rate changes during exercise and under the influence of adrenaline 2.65describe the structure of arteries, veins and capillaries and understand their roles 2.66understand the general structure of the circulation system to include the blood vessels to and from the heart, the lungs, the liver and the kidneys

Small organisms just use diffusion 2.49Explain why unicellular organisms can rely on diffusion for movement of substances in and out of the cell The smaller the organism, the greater the SA: Vol ratio, meaning diffusion of nutrients, waste and gases in and out is FAST

Large organisms need systems 2.50Explain why unicellular organisms can rely on diffusion for movement of substances in and out of the cell Systems for exchange (breathing and digestive) provide SURFACE AREA The circulatory system deals with the problem of DISTANCE - diffusion just has to work for the last fraction of a millimeter. Large organisms: Smaller the SA: Vol ratio Bigger distance Making diffusion of nutrients, waste and gases in and out SLOW

Plasma, red & white cells, platelets 2.57Describe the composition of the blood: red blood cells, white blood cells, platelets and plasma

The role of plasma 2.58 understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy Contains the cells and the protein that are essential components of the blood Carries substances to the tissues: digested food, hormones Removes waste from tissues: carbon dioxide, urea...and carries heat energy The liquid part of the blood

Structure & function of red blood cells 2.59 describe the adaptations of red blood cells for the transport of oxygen, including shape, structure and the presence of haemoglobin …haemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it. flexible so it can squeeze through the capillaries. A small biconcave disc: the flat shape provides a large surface area and short distance to maximize the rate of diffusion without a nucleus so there is maximum space for…

Blood: defending against pathogens 2.60 describe how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen the two main types of white cells are lymphocytes and phagocytes. lymphocytes fight disease by making antibodies to destroy pathogens by making them stick together Phagocytes engulf and digest pathogens using enzymes.

Vaccination 2.61 understand that vaccination results in the manufacture of memory cells, which enables future antibody production to the pathogen to occur sooner, faster and in greater quantity When a lymphocyte recognizes an antigen, it multiplies and leaves some memory cells One lymphocyteSome of lymphocytemultiplies tothese recognizesfight thelymphocytes the pathogeninfectionremain as memory cells

How and why your blood clots 2.62 recall that platelets are involved in blood clotting, which prevents blood loss and the entry of microorganisms 1. Platelets are fragments of cells, broken off larger cells. 2. When blood vessel walls are damaged, platelets produce chemicals that convert fibrinogen into fibrin 4. The clot prevents blood loss and the entry of pathogens into the body 3. Fibrin forms a net that traps other blood cells to form a blood clot.

The heart describe the structure of the heart and how it functions Left Ventricle Left Atrium Right Atrium Right Ventricle tricuspid valve Pulmonary vein Aorta to Head and BodyPulmonary artery Vena Cava from Body semilunar valves bicuspid valve

The heart describe the structure of the heart and how it functions blood from the body blood from the lungs blood is forced through the tricuspid and bicuspid valves into the ventricles The ventricles contract, putting pressure on the blood. This closes the tricuspid and bicuspid valves and forces the semilunar valves open. Blood is forced into the aorta and pulmonary artery

Exercise, adrenaline and the heart 2.64 understand that the heart rate changes during exercise and under the influence of adrenaline The cardiovascular centre in the medulla controls the heart rate by sending signals to the SA node that make the heart speed up or slow down. During exercise, CO 2 levels rise, and the medulla speeds up the heart rate, which increases the amount of blood going to the lungs. When you have a shock, adrenaline is released into the blood. Adrenaline increases the heart rate.

Arteries, veins and capillaries 2.65 describe the structure of arteries,veins and capillaries and understand their roles

Circulation to and from the organs 2.66 recall the general plan of the circulation system to include the blood vessels to and from the heart, the lungs, the liver and the kidneys lungs head & arms liver digestive system kidneys legs pulmonary artery aorta pulmonary vein vena cava LeftRight hepatic artery renal arteryrenal vein hepatic vein hepatic portal vein