third section of module revision

1. REVISION Part 3

2. What am I?

3. BLOOD

4. Name the cell e

7. Is a ‘straw’ coloured liquid which suspends white and red blood cells together with platelets in the Blood

8. Arteries A rteries carry high pressure blood A way from the heart. Lumen Endothelium Elastic Fibres & Smooth Muscle

9. Veins V eins carry low pressure blood back to the heart. They have thinner, less elastic walls and have V alves to prevent backflow of blood . Large Lumen Endothelium

12. Label me

13. Aorta Pulmonary vein Pulmonary artery Vena cava Vena cava

14. The Heart 1. Deoxygenated blood (i.e. blood without oxygen) enters through the vena cava into the right atrium 2. It’s then pumped through the tricuspid valve into the right ventricle 3. It’s then pumped through the semi-lunar valve up to the lungs through the pulmonary artery 4. Oxygenated blood from the lungs enters through the pulmonary vein into the left atrium 5. It’s then pumped through the bicuspid valve into the left ventricle 6. It’s then pumped out of the aorta to the rest of the body

20. What Are the Stages of Mitosis? 1. DNA all spread out in long strings 2. DNA forms into chromosomes (Remember, the double arms are already duplicates of each other) 3. Chromosomes line up at the centre and the cell fibres pull them apart

21. 4. Membranes form around the two sets of chromosome threads. (These become the nuclei of the daughter cells) 5. The threads unwind into long strands of DNA ……. and the whole process starts again!

23. MITOSIS MEIOSIS Replication followed by ONE DIVISION Replication followed by TWO DIVISIONS Results in SAME number of chromosomes Results in HALF the number of chromosomes Occurs in ALL normal body cells Occurs in special cells in OVARIES and TESTES Used for GROWTH & REPAIR Used for production of EGG & SPERM

25. Egg Haploid 23 chromosomes Sperm Haploid 23 chromosomes Zygote (fertilised egg) Diploid 46 chromosomes Cell in ovary Diploid 46 chromosomes Cell in testes Diploid 46 chromosomes Fertilisation Meiosis Meiosis Mitosis