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Results for: 'Conduction of action potentials'

Neural Reflex Arc Animation

By: Administrator, Views: 9833

A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the bra...

Heart sounds

By: HWC, Views: 6524

During a normal, healthy heartbeat, or what we call a cardiac cycle, the top two chambers of the heart, called the atria, contract simultaneously. Then, as they relax, the bottom two chambers, called the ventricles, contract. This explains what happens during a cardiac cycle, but what it doesn't ...

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

By: HWC, Views: 6763

• 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...

Lymphatic System Animation

By: Administrator, Views: 449

Blood and lymph are two of the body's main fluids and are circulated through two separate but interconnected vessel systems. Blood is circulated by the action of the heart, through the circulatory system consisting largely of arteries, veins, and capillaries. Lymph does not actually circulate. ...

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

By: HWC, Views: 7002

• Most cells which have CD8 on their surface become cytotoxic T cells (Tc cells). • CD8 T cells recognize a foreign antigen when it is presented in conjunction with the protein, MHC-I. • Nearly all nucleated cells in the body express MHC-I molecules. • T cells that recognize self-pe...

What are Taste Receptors? How Does it Work? Animation

By: HWC, Views: 3501

Do you ever wonder how you can taste the foods you eat? It all starts with taste receptors in your muscular tongue. Taste receptor neurons are found in your taste buds but you are not looking at the taste buds. The raised bumps on the surface of the tongue that you see are specialized epith...

Nerve Impulse Transmission Animation

By: Administrator, Views: 10011

How nerves transmit impulses. Stimulation of a nerve occurs at a receptor. Sensory receptors Specialized to specific types of stimulation such as heat, cold, light, pressure, or pain. React by initiating a chemical change or impulse. All-or-none principle Means that no transmission occ...

Hormonal feedback loop components

By: HWC, Views: 6802

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 after b...

Enzyme-Catalyzed Reactions

By: HWC, Views: 6144

S P Substrate in great excess ([S] -- [E]) (More correctly [S] -- KM, but more on this later) Zero order rate equation: v = k where k is the zero-order rate constant (with respect to substrate). (More correctly [S] -- KM, but more on this later) Substrate forms complex with enzyme. ...

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