Search results for: 'diploid germ cells'

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By: HWC, Views: 4877

In the late 1920s, Fred Griffith was attempting to develop a vaccine against a bacterium that causes pneumonia. To find out why two strains of the bacteria differed in their deadliness, he injected mice with four different mixtures. Mice injected with R cells remained healthy. When Griffith ex...

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Cell mediated immune response to a viral infection Animation

By: HWC, Views: 3759

Intracellular pathogens are the targets of cell-mediated immune response. The process begins when a virus infects a macrophage. Another macrophage engulfs the same virus or an antigen from it. In both cells, enzymes cleave the viral antigens into small bits. The fragments move to the cell sur...

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Introduction to Insulin

By: Administrator, Views: 11837

The islets of Langerhans are composed of three major types of cells: Alpha cells secrete glucagon, elevating blood sugar. Beta cells secrete insulin, maintaining normal blood sugar. Delta cells secrete somatostatin, which suppresses release of glucagon and insulin. Hyposecretion or inadequa...

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Helper T cell receptors, activation, proliferation, differentiation & action

By: HWC, Views: 7826

• Most cells which have CD4 on their surface become Helper T cells (TN cells). • The CD4 1 cells only recognize a foreign antigen when it is presented with an antigen presenting immune cell (APC) that includes MHC-II protein. • The Helper T cell antigen receptor must match the presented...

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Red Blood Cells - Erythropoietin (EPO)

By: HWC, Views: 7723

• The endocrine system maintains many body conditions within normal limits with feedback loops. Each endocrine feedback loop maintains homeostasis using the following components: • Stimulus - a change in a body condition. • Production cell - an endocrine cell that produces a hormone aft...

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Vascular tissues in a corn stem and a buttercup root

By: HWC, Views: 2235

Vascular tissues in a corn stem and a buttercup root. The cells that make up each tissue. Xylem conducts water and dissolved ions. It also helps mechanically support a plant. The cells, called vessel members and tracheids, are dead at maturity. Their lignified walls interconnect and serve as p...

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Bone cells and tissues - tissue composition and cells

By: HWC, Views: 8569

Bone tissue consists of bone cells secreting bone matrix. • The extracellular bone matrix is a connective tissue that is hard, yet flexible. • Collagen fibers provide flexibility. • Inorganic mineral salts (primarily calcium phosphate, or hydroxyapatite) provide hardness. • Togethe...

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Inflammatory response Animation

By: HWC, Views: 4284

Any tissue damage or bacterial invasion can bring about inflammation. The inflammatory response can be triggered by an invasion of bacteria, or by a cut or other physical damage to cells. Chemicals, such as histamine, released by the bacteria or damaged cells. accumulate in the tissue. Thes...

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Cellular defenses (natural killer cells, phagocyte types & process of phagocytosis)

By: HWC, Views: 7474

• Lymphocytes that rapidly defend against abnormal (cancer) or virus-infected cells. • Found in blood, spleen, lymph nodes, and red bone marrow. • Lack receptors for binding with specific antigens. • Act upon cells displaying abnormal MHC antigens. • NK cells destroy cells in ...

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