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

By: HWC, Views: 6743

• 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...

Bone processes - resorption and deposition, remodeling and response to stress in adult bones

By: HWC, Views: 6908

• The process of remodeling bone tissues involves bone cells resorbing or depositing minerals into bone tissue. • During resorption, bone cells break down bone tissue and release calcium and other minerals for use by other cells in the body. • Bone cells also rebuild bone tissue by depo...

Plant Defense Mechanisms from Pathogens

By: HWC, Views: 6084

Plants and pathogens have coevolved such that pathogens can recognize plants by the sugars, or other molecules, they produce. Plants, in turn, can recognize pathogens by the molecules they produce. The ability to recognize pathogens allows plants to activate defense systems that can prevent wides...

Introduction to Human Immunodeficiency Virus (HIV)

By: Administrator, Views: 9555

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...

T cell receptors

By: HWC, Views: 6334

• T cells are responsible for cell-mediated immunity. • Each T cell contains a unique form of T cell receptor (TCR) on its membrane. • These T cell receptors are produced through a process of genetic recombination which is able to produce millions of different variations. • Each T ce...

Flexor reflex & Crossed extensor reflex

By: HWC, Views: 6567

• The flexor reflex is a response to pain. This reflex is polysynaptic, ipsilateral, and intersegmental. • Pain receptors are stimulated causing increased frequency of action potentials to be generated and conducted along the sensory neuron axon. • The sensory impulses excite several ass...

Hemodynamics Animation

By: Administrator, Views: 10389

Hemodynamics is the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms, such as hydraulic circuits are controlled by control systems. Hemodynamic response continuously monitors and adjusts to conditions in the body and its environment.

Muscle Twitch and Muscle Tension - Motor unit size and force

By: HWC, Views: 6893

• A motor unit is a group of muscle cells controlled by a single neuron. • A stimulus of sufficient intensity will cause all the cells in the motor unit to contract. • A single contraction, caused by a single action potential, is called a muscle twitch. • Latent period: A brief per...

Neural Reflex Arc Animation

By: Administrator, Views: 9814

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...