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Conduction of action potentials

By: HWC, Views: 7884

• Action potentials must be rapidly conducted over long distances in order for the nervous system to communicate with other cells. • Propagation of an action potential uses processes similar to those that generate the potential at the trigger zone. • a When a graded potential reaches ...

Molecules, Membrane Permeability and Structure

By: HWC, Views: 7184

Organisms are not isolated system at equilibrium and need to intake nutrients and electrolytes as remove wastes. Similarly Cells within an organism must also exchange compound by passing them through membrane. The permeability of a membrane is the rate of passive diffusion of molecules th...

Corpus Callosum Animation

By: Administrator, Views: 10582

The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick, nerve tract consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental mammals. It spans part of the longitudinal fissure, con...

Resting membrane potential - electrical polarity and maintenance requirements

By: HWC, Views: 7460

• A resting membrane potential exists when there is a buildup of: 1. positive ions outside the membrane. 2. negative ions inside the membrane. • Membranes with opposing charges are said to be polarized. • The difference in charge applies only to the small distance across the membran...

Functional zones in a mitochondrion

By: HWC, Views: 5657

A mitochondrion has a double membrane system. The outer membrane faces the cytoplasm. The inner membrane divides the organelles interior into two compartments. The enzymes that carry out the second stage reactions are in the semifluid matrix inside the inner compartment. Embedded in the ...

Pores and Ion Channels

By: HWC, Views: 6906

Transmembrane channels, also called membrane channels, are pores within a lipid bilayer. The channels can be formed by protein complexes that run across the membrane or by peptides. They may cross the cell membrane, connecting the cytosol, or cytoplasm, to the extracellular matrix. Membrane po...

Primary Active Transport - electrochemical gradient and ion transport / water movement

By: HWC, Views: 7845

Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consis...

Requirements for nervous signals

By: HWC, Views: 7678

• The function of neurons is to allow communication between cells, thereby maintaining homeostasis. • Electrical signals, called membrane potentials, travel along the membranes of the neurons. • Voltage variability and distance traveled determine the type of nervous signal. 1. Graded...

Membrane transport proteins - pores, gated channels and pumps

By: HWC, Views: 7842

• 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...