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Summation - defined, spatial, temporal & AP generation or not

By: HWC, Views: 7662

If several presynaptic end bulbs release their neurotransmitter at about the same time, the combined effect may generate a nerve impulse due to summation Summation may be spatial or temporal • A typical neuron may have thousands of synapses. A corresponding number of postsynaptic membrane ...

Factors that affect conduction rates (myelination, axon diameter & temperature)

By: HWC, Views: 7873

• Several factors determine the rate of conduction of action potentials: • Myelination • Axon diameter • Temperature • The step-by-step depolarization of an axon is called continuous conduction and occurs along unmyelinated axons. • Neurons in the PNS have many axons that ...

Types of antimicrobial substances (interferons & complement protein)

By: HWC, Views: 7771

• Found in blood and interstitial fluids. • Discourage microbial growth. • Include interferon and complement proteins. • Produced and released by virus-infected lymphocytes. • Enter new cells and inhibit viral replication. • Act against a large variety of viruses (non-speci...

Krebs cycle : Formation of acetyl coenzyme A and Electron transport chain

By: HWC, Views: 7824

The oxidation of glucose to produce ATP is cellular respiration. Four sets of reactions are involved: Glycolysis Formation of acetyl coenzyme A Krebs cycle reactions Electron transport chain reactions • The second pathway of glucose catabolism, formation of acetyl coenzyme A, is a transi...

Origin of organelles Animation

By: HWC, Views: 1390

Possible origins of the nucleus and other organelles. Some prokaryotic cells have infoldings of their plasma membrane. These infoldings may have served as channels from the cytoplasm to the cell surface. These membranous folds may have evolved into the endoplasmic reticulum and the nuclear e...

Chloroplast Structure & Light Dependent Reactions (Photosystem 1 and 2 Cyclic Electron Flow)

By: HWC, Views: 7324

The leaf is the principle photosynthetic organ of the plant. This is a cross section of a leaf. The rectangular-shaped cells are part of the photosynthetic tissue called the palisade mesophyll. Each photosynthetic cell can contain several hundred organelles known as chloroplasts. The chlorop...

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

By: HWC, Views: 7476

• 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 ...

Type of Cell Junctions - Desmosome, Hemidesmosomes and Gap Junctions

By: HWC, Views: 8090

Cell Junctions: Cell junctions are found in some multi-cellular organisms. They exist of complexes and are found between cells and between cells and other structures. The junctions provide a way for cells to connect and exchange signals. What are tight junctions, desmosomes, and gap junctions...

T cell receptors

By: HWC, Views: 7427

• 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...