Natural sciences

• Eye piece (ocular):

  • Has a lens that magnifies/enlarges, e.g., 10X
• Tube:

  • Can be moved up and down to change the distance of lenses
• Coarse focus knob:

  • Moves the tube up and down to focus the specimen
• Fine focus knob:

  • Used to obtain a clear image
• Arm:

  • Joins the base and the stage
• Rotating Revolving nose piece:

  • Has different power objectives (lens) e.g., low, medium, high
• Objectives:

  • Used to place the slide on
• Table/stage:

  • Holds the slide in place
• Clamps/Stage clips:

  • Controls the amount of light that enters
• Diaphragm:

  • Provides light to view specimen
• Light source (electric/mirror):

  • Supports the microscope
• Base:

  • Supports the microscope
• Total eye piece magnification & power objective (1/m/n)
• Arteries:

  • Transport oxygen-rich blood from the heart to the cells in the body
  • Walls are thick, muscled and elastic to withstand pressure
  • The aorta is the main artery
  • The pulmonary artery transports deoxygenated blood from the heart to the lungs
• Veins:

  • Transport deoxygenated blood back to the lungs via the heart
  • Thinner, less muscled walls to handle lower pressure
  • The pulmonary vein transports oxygen-rich blood from the lungs to the heart. It is the only vein that transports oxygen-rich blood
• Capillaries:

  • In the organs, arteries branch into many small, narrow tubes called capillary blood vessels
  • The walls of capillaries are very thin, allowing cells to come into close contact with the blood
  • Capillaries supply cells with oxygen and nutrients, and remove waste products and carbon dioxide
  • Capillaries unite again to form veins
• Heart:

  • The heart is centrally situated in the chest between the two lungs
  • The two sides of the heart are separated by a muscular wall (septum)
  • Both sides are divided into two chambers, making a total of four chambers
  • The upper two heart chambers (atria) receive blood from the veins, while the lower two chambers (ventricles) pump blood to the rest of the body through the arteries
  • The heart is a hollow muscle that contracts and relaxes continuously
• Functions of the heart:

  • The heart pumps deoxygenated blood to the lungs to get rid of carbon dioxide
  • Blood enriched with oxygen flows back to the heart from the lungs and is then pumped to the rest of the body to supply it with oxygen
• Interesting facts:

  • Humans have a closed circulatory system where blood circulates through the body without leaving the blood vessels
  • The cardiac muscle functions automatically, allowing a heart removed from the body to keep beating for hours without nerve stimulus
  • Dr. Chris Barnard performed the first successful human heart transplant on 3 December 1967 in Cape Town
• Blood components:

  • Plasma: the liquid part of blood that mainly consists of water and transports nutrients, waste products, and gases in dissolved form
  • Red blood cells: transport oxygen from the lungs to the body, are large and flexible, and lack a nucleus
  • White blood cells: protect the body against infection and disease, fight germs during infections, and play a role in blood clotting
  • Platelets: important for blood clotting and are produced in the bone marrow
• Drawing showing the structure of a plant cell

  Cell wall

  Cell membrane

  nucieus

  cytoplasm

  chloroplast

  tonoplast

  cell sap

  vacuole

  mitochondinon

  23/1

  -non-living-CELLULOSE

  que shope PICID protection

  -living, thin selectively PERMEABLE only certain subsiunces to enter exit controls all activities

  Lonly in plant cells (Green plants)

  Contains CHLOROPHYLL

  membrane surrounds vacuole

  shape of cell, storage for water, nutrients and waste

  cellular respiration

  Coll1206+02 ENEREY+

  대 2+H20

  • animal cells mitochondic

  -more energy