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Cell mediated immune response to a viral infection Animation

By: HWC, Views: 3748

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...

Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 7873

Once the muscle cell has been excited it will contract. • A muscle action potential will trigger the release Of Ca2+ ions into the sarcoplasm. • The Ca2+ ions bind to the regulatory proteins and trigger contraction. • Within skeletal muscle cells are structures that provide the ability...

Introduction to Insulin

By: Administrator, Views: 11824

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...

Frequency of stimulation and force (Recruitment of motor units and force)

By: HWC, Views: 8043

• Muscle tension depends on the frequency of stimulation. • Muscle twitch: First stimulus. • Wave summation: When a second stimulus excites a partially relaxed muscle, producing a stronger contraction. • Unfused tetanus: Successive stimulations at the same frequency, producing a se...

Olfaction. or the sense of smell

By: HWC, Views: 5147

Do you ever wonder how you can distinguish thousands of different odors? Olfaction. or the sense of smell, is used by all mammals to navigate, find food, and even find mates. We have millions of olfactory receptors for smelling in our nose. These receptor neurons bind water-soluble or volatil...

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

By: HWC, Views: 7813

• 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...

Red Blood Cells - Erythropoietin (EPO)

By: HWC, Views: 7711

• 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...

Brief Summary on Photosynthesis - Animation

By: HWC, Views: 6720

Can increase its weight by 150 pounds as it grows. Where does the new tissue come from? From the soil? From water? Or possibly from the air? The amazing truth is that new material. comes from an invisible gas in the air. In the process of photosynthesis, plants capture carbon dioxide ga...

Components of the Nervous System

By: Administrator, Views: 433

The nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue...