Blood clot. Coloured scanning electron micrograph (SEM) of a blood clot from the inner wall of the left ventricle of a human heart. Red blood cells (erythrocytes) are trapped within a fibrin protein mesh (cream). The fibrin mesh is formed in response to chemicals secreted by platelets (pink), fragments of white blood cells. Clots are formed in response to cardiovascular disease or injuries to blood vessels. Connective tissue (orange) is also seen.
Nerve bundle. Coloured scanning electron micrograph (SEM) of a freeze-fractured section through a bundle of myelinated nerve fibres. Myelin sheaths (yellow) can be seen surrounding the axons (blue). Perineurium (connective tissue, pink) surrounds the nerve bundle while endoneurium divides the individual fibres.
Ruptured venule. Coloured scanning electron micrograph (SEM) showing stacks (rouleaux) of red blood cells exposed inside a torn venule. A venule is a very small blood vessel in the microcirculation that allows deoxygenated blood to return from the capillary beds to the larger blood vessels (veins). Red blood cells are the most abundant cell in the blood. They have no nucleus and are about 7 micrometers across. Magnification: x2300 when printed at 10 centimetres wide.
Coloured scanning electron micrograph (SEM) of rods (blue) and cones (red), the light sensitive cells in a human retina. Rods aid vision in dim light, while cones allow colour vision | Ralph C. Eagle, Jr. | SCIENCE PHOTO LIBRARY
Moss spore capsule: Colored Scanning electron micrograph (SEM) of moss (Funaria sp) spore capsule. : pics
Ruptured capillary. Coloured scanning electron micrograph (SEM) of a red blood cell squeezing out of a torn capillary. A capillary is the smallest type of blood vessel, often only just large enough for red blood cells to pass through. Red blood cells (erythrocytes) are biconcave, disc-shaped cells that transport oxygen from the lungs to body cells. Credit: STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY
Fertilization. Colored scanning electron micrograph (SEM) of a sperm (blue) attempting to penetrate a human egg (orange).
Lung cancer cell division. Coloured scanning electron micrograph (SEM) of a lung cancer cell during cell division (cytokinesis). The two daughter cells remain temporarily joined by a cytoplasmic bridge (centre). Cancer cells divide rapidly in a chaotic, uncontrolled manner. They may clump to form tumours, which invade and destroy surrounding tissues.
Colored scanning electron micrograph of the blood vessels coming from the optic disc. Way cool.
Brain tumour. Coloured scanning electron micrograph (SEM) of a glioma, a type of tumour that arises from glial cells of the central nervous system. The most common site for gliomas is the brain. They can be either low or high-grade, with the latter having the worse prognosis. Magnification: x8000 when printed at 10 centimetres wide. Credit: STEVE GSCHMEISSNER