Images Dated 10th September 2003

Blood cells, SEM

Blood cells and platelets. Coloured Scanning Elec- tron micrograph (SEM) of human blood showing red and white cells and platelets. Red blood cells (erythrocytes) have a characteristic biconcave- disc shape and are numerous. These large cells contain haemoglobin, a red pigment by which oxygen is transported around the body. They are more numerous than white blood cells (yellow). White blood cells (leucocytes) are rounded cells with microvilli projections from the cell surface. Leucocytes play an important role in the immune response of the body. Platelets are smaller cells (pink) that play a major role in blood clotting

© National Cancer Institute/Science Photo Library

LM of epidermis cells of Tradescantia

Light micrograph of the epidermal cells on the surface of the leaf of the Trinity Flower Tradescantia x andersoniana. In the centre of this image is a stoma, or pore. It is through pores such as these that gases may reach the inside of the leaf: the rest of the epidermal cells being impermeable. Two guard cells surround the pore itself. Changes in hydrostatic pressure within these cells govern the pore's size and thus the rate of gas transfer across the epidermis. Magnification x400 at 35mm size

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

Coloured TEM of skeletal muscle and nerve fibres

Skeletal muscle. Coloured transmission electron micrograph (TEM) of a section through skeletal (striated) muscle (pink). There is also a band of connective tissue (yellow). The muscle myofibrils, running from top to bottom, are split into contra- ctile units called sarcomeres by the discontinuous Z lines (black). A sarcomere contains protein filaments which can slide over each other to allow the muscle to contract. In the connective tissue are nerve fibres (light green) surrounded by the myelin sheaths (dark green) of Schwann cells. Granulated nuclei (pink) are also visible. Running from top centre to centre is part of a blood vessel. Magnification: x1, 300 at 5x7cm size. x4500 at 7x9.5

© Steve Gschmeissner/Science Photo Library