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Coaductile pathway, Timing of contraction signal & Conduction system and ECG

By: HWC, Views: 7940

• When the system is healthy, the signal to contract the entire conduction system originates in the SA node - known as the heart's pacemaker. • The SA node triggers contraction because it depolarizes at a faster rate than other parts of the conduction system. • The wave of excitation fr...

Immune responses Animation

By: HWC, Views: 4570

Overview of interactions in antibody-mediated and cell-mediated immunity Animation The antibody mediated immune response begins when a naive B cell encounters antigens from a pathogen, such as a bacterium. The B cell binds, processes, and displays this antigen. It is now an antigen-presenti...

How Broken Bones Repair Themselves

By: Administrator, Views: 403

Bone healing, or fracture healing, is a proliferative physiological process in which the body facilitates the repair of a bone fracture. Generally bone fracture treatment consists of a doctor reducing (pushing) displaced bones back into place via relocation with or without anaesthetic, stabili...

Cellular slime mold life cycle Animation

By: HWC, Views: 1972

Life cycle of Dictyostelium discoideum, a cellular slime mold Animation. Amoeba-like slime mold cells live in the soil, where they feed on bacteria. The free-living cells grow and reproduce by mitosis. When food dwindles, the amoebas stream toward one another in response to a chemical...

Cellular Defects - Osteoblasts, Osteoclasts and Osteocytes

By: HWC, Views: 7337

■ Metabolically active bone-building cells that secrete astroid. ■ Cover surfaces of newly formed bone and respond to growth stimuli ■ Less responsive to growth factors as the body ages. ■ Contribute to hone loss once their reproductive and biosynthetic potential lessens....

Introduction to filtration - filtrate formation and composition

By: HWC, Views: 7925

• At the nephron, the three process responsible for the formation of urine include: • Glomerular filtration. • Tubular reabsorption. • Tubular secretion. • During filtration, a filtrate is formed within the renal tubule. • Reabsorption is the conserving of water and many s...

Embryonic development - Weeks 5 to 8

By: HWC, Views: 7837

• The second month of development is characterized by rapid development of the head and limbs as well as continued organogenesis. • During the fifth and sixth weeks growth of the brain, and therefore head, is rapid. • Hands and feets begin to form. • During week seven, even more deve...

Introduction to Pre-eclampsia

By: Administrator, Views: 10773

Pre-eclampsia (PE) is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine. When it arises, the condition begins after 20 weeks of pregnancy. In severe disease there may be red blood cell breakdown, a low blood platelet c...

Introduction to Human Immunodeficiency Virus (HIV)

By: Administrator, Views: 10649

Human immunodeficiency virus gains entry into helper T cells, uses the cell DNA to replicate, interferes with normal function of the T cells, and destroys the normal cells. 1 in 10 persons with AIDS: age 50 or older. 4% of all AIDS cases: age 65 or older. AIDS’ main form of treatment: an...