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Results for: 'membrane permeability'
Nucleic acid digestion - brush border enzymes, end products & transport mechanism
By: HWC, Views: 7508
• Further digestion occurs at the microvilli (brush border) of the epithelial cells of the villi in the small intestine. • Two brush border enzymes complete nucleic acid digestion: • Phosphatases, which catalyze the cleavage of a phosphate to form a nucleoside (nitrogenous base and pent...
Net filtration pressure and lymph formation, edema & blood velocity
By: HWC, Views: 7490
Bulk flow -net filtration pressure and lymph formation • The net filtration pressure (NFP) is the force promoting filtration minus the force promoting reabsorption. • At the arterial end of an ideal capillary, the filtration pressures are stronger. The result: net filtration. • At t...
By: Administrator, Views: 11348
The mouth or oral cavity is formed by: - The hard and soft palates at the top or roof - the cheeks - the tongue - the lips Contains the teeth and salivary glands. The gingivae (gums) surround the necks of the teeth. The lingual frenulum is a thin fold of mucous membrane that connects...
By: Administrator, Views: 10686
In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to neuronal function: neurons are cells that are specialized to pass signals to individual tar...
Summation - defined, spatial, temporal & AP generation or not
By: HWC, Views: 7647
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: 7855
• 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: 7749
• 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: 7809
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: 1365
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...
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