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B cells and antibodies

By: HWC, Views: 7771

What Are Antibodies? Antibodies, also known as immunoglobulins, are Y-shaped proteins that are produced by the immune system to help stop intruders from harming the body. When an intruder enters the body, the immune system springs into action. These invaders, which are called antigens, can be vi...

Endocytosis -Types and Phagocytosis

By: HWC, Views: 7015

Endocytosis is the process by which a substance is brought inside a cell without having to pass through the cell membrane. It is the opposite of endocytosis, the process by which substances exit the cell without having to pass through the cell membrane. Exocytosis – membrane-enclosed secret...

Membrane transport proteins - pores, gated channels and pumps

By: HWC, Views: 7086

• a Three different types of membrane ion transport proteins are required to produce and carry electrical signals: • Pores • Gated channels • Na+/ K+ pump • Pores are always open and allow the diffusion of Na+ and K+ ions across the membrane, down their concentration gradients...

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

By: HWC, Views: 7289

• 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...

Component of feedback systems & Communication and regulation of body systems

By: HWC, Views: 7071

• Primary responsibility for communication and regulation in the body is shared by the nervous and endocrine systems. • The two systems work alone or together in specialized physiological processes called feedback systems to maintain homeostasis. • Feedback systems - or loops - are ...

Nerve Impulse Transmission Animation

By: Administrator, Views: 10372

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...

Reflex arc construction

By: HWC, Views: 6899

• Somatic reflexes are the rapid, predictable, and automatic responses of skeletal muscle to changes in stimuli. • A reflex arc is the pathway followed by the nerve impulse producing the reflex. • Reflex arcs include: • Sensory receptor • Sensory neurons • Integrating c...

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 6229

Extracellular signals produce specific responses in target cells through the action of intracellular second messengers. Here, we focus on three second messengers, IP3, DAG, and Ca2+, all involved in the inositol-lipid signaling pathway. A hormone-receptor signal on the cell surface leads to the a...

Neural Reflex Arc Animation

By: Administrator, Views: 10178

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...