Molecules, Blood and Gas Exchange Unit F211

The Blood(1.1.1) Studying cells can provide valuable information about health.

Learning Objective (1.1.1) a.describe how blood samples are taken and blood smears (films) are made.

Task In your group, come up with a strategy to describe how blood samples are taken. REMEMBER TO USE ALL KEY WORDS.

Learning Objective (1.1.1) a.describe how blood samples are taken and blood smears (films) are made. d. describe the structure, as seen with a light microscope, of red blood cells (erythrocytes), neutrophils, lymphocytes, monocytes and macrophages as specialised cells with particular functions related to their structures.

Task In group of two, Read how to make a blood smear/ blood film. Practice making a blood film using the equipments provided.

Task Now, write step by step method to make a blood film. You are to work individually.

Task Compare your procedure with your partner. Use the book to mark your partners work.

Differential Stain Erythrocytes Biconcave discs. Relatively large surface area to volume ratio. Cytoplasm is packed with a pigment, a protein called haemoglobin. Mature erythrocytes have no nucleus. Very small and flexible.

Leucocytes Neutrophils Have small granules in the cytoplasm. Engulf microorganisms by phagocytosis.

Lymphocytes Have a large, darkly stained nucleus surrounded by a thin layer of cytoplasm. There are two kinds of lymphocytes, T and B lymphocytes. Both look the same. B lymphocytes produce antibodies. T lymphocytes have several functions including cell destruction.

Monocytes Are the largest kind of leucocyte. They have large, been- shaped nucleus and clear cytoplasm. They spend 2-3 days in the circulatory system, then they move to the tissues. In the tissues, they become macrophages, engulfing micro organisms and other foreign materials

Identify the cells

Task In groups of two, use the bio viewer, look at the blood films, identify the different blood cells and draw and label them. Under each diagram, list at least two features with explanation.

Homework Read information from work sheets and answer questions Due next Wednesday.

Calculating Magnification g: calculate the linear dimensions and magnification of drawings or photographs of cells

How to calculate magnification? Magnification= Rearrange the formula to find the real size of the structure. Size of the structure in the picture Real size of the structure

Remember A micrometer (µm) is one millionth of a meter. 1 1µm= 10- m 1 µm= 10 -³ mm Always measure the structure in millimetres. This means you can convert this to micrometers by multiplying by 1000, i.e. adding 3 zeros.

Task Answer questions 1 and 2 from the spread.

Homework Produce a booklet to explain to a patient about her/ his blood test. You should include how to take a blood sample, make a blood film and stain it, also, explain how to identify blood cells from the blood smear. You should include diagrams. Due next Thursday.

Using a Haemocytometer c

Learning Objectives describe the use of a haemocytometer to count the numbers of erythrocytes and leucocytes (to include details of dilution);

Haemocytometer

Calculating the number of erythrocytes in 1mm³ of the original blood sample The triple lined squares measure exactly 0.2 x 0.02 mm The platform is exactly 0.1 mm below the cover slip. This means when you view one of the triple lined squares under the microscope, you are looking at a volume of exactly 0.1x0.2x0.2 mm = 0.004mm³ Number of RBCs in the original sample in 1 mm³= 1/0.02 x number of cells counted in five triple lined squares x dilution. Remember the dilution is 200

Calculating the number of leucocytes in 1mm³ of the original blood sample Count the number of WBCs in the four corner squares. These squares measure exactly 1x1 mm. the depth of the chamber is 0.1mm. This means that each square has a volume of 1x1x0.1 = 0.1mm³ Number of WBCs in the original sample in 1 mm³= 1/0.4 x number of cells counted in four corner squares x dilution. Remember the dilution is 20

Homework Homework task: Pupils to write a detailed method in order to enable another student to repeat the process and generate accurate and reliable data

Lipids t (t) describe, with the aid of diagrams, the basic structure of glycerol and fatty acids; (u) outline the formation of triglycerides by the condensation reactions between glycerol and fatty acids;

List the types of molecules you need to break down (digest) from your food.

Introduction to lipids Lipids are a diverse group of compounds that are insoluble in water but soluble in organic solvents such as ethanol. The most common types of lipid are triglycerides (sometimes known as true fats or neutral fats), but other important lipids include waxes, steroids and cholesterol. Like carbohydrates, lipids contain carbon, hydrogen and oxygen, but they have a higher proportion of hydrogen and a lower proportion of oxygen.

The structure of triglycerides

The structure of phospholipids