Glossary of Physiology Terms
There are
7 glossary search results for:
skeletal muscle
Abbreviation:
ACh
Definition:
Acetylcholine (ACh) is a chemical neurotransmitter used by the central nervous system (CNS) as well as the peripheral nervous system (PNS). Acetylcholine is a classical neurotransmitter and, in fact, it was the first of the classic neurotransmitters to be discovered. It was discovered in 1914 by Henry Hallett Dale while conducting experiments on the heart.
Acetylcholine is the neurotransmitter used by the somatic division of the nervous system at the neuromuscular junction (where a somatic motor neuron makes synaptic contact with a skeletal muscle cell). Acetylcholine is also used extensively by both branches of the autonomic nervous system; sympathetic and parasympathetic. It is the primary neurotransmitter released in autonomic ganglia by preganglionic autonomic neurons. It is also the primary neurotransmitter released by parasympathetic postganglionic neurons. A few sympathetic postganglionic neurons also release acetylcholine. The diverse actions of acetylcholine are exerted via the activation of nicotinic and muscarinic ACh receptors.
Other resources:
Acetylcholine (Wikipedia)
Abbreviation:
CI
−Definition:
The main anion (negatively charged ion) of the extracellular fluid.
Cloride (Cl
−) plays an important role in several physiological processes such as the action potential of skeletal muscle cells, CO
2 transport in blood (via Cl
−/bicarbonate exchange across the plasma membrane of red blood cells), and many other processes.
The extracellular concentration of Cl
− is about 110 mM. The intracellular concentration of Cl
− is about 10 mM.
Definition:
A potent blocker of nicotinic cholinergic receptors (nicotinic acetylcholine receptor, nAChR) found at the neuromuscular junction. At small doses, curare can lead to muscle weakness. At high doses, curare can lead to paralysis of skeletal muscles, which would also result in asphyxiation (and ultimately death) due to paralysis of the diaphragm. Curare was commonly the active agent of poison arrow.
Other resources:
See Wikipedia
Definition:
Electrophysiology is the study of the electrical properties of biological macromolecules, cells, tissues, and organs. Electrical signals such as voltage and/or current are generally measured. Examples include measuring changes in the membrane voltage of excitable cells (e.g., neurons, muscle cells, and some endocrine cells) during an
action potential. The current carrried by ions as they permeate the pore of ion channels can also be measured - both at the single-channel level (single-channel current), as well as the macroscopic current resulting from the activity of a population of channels. As another example, electrical measurements may involve recording voltage changes at the surface of the skin that result from the activity of skeletal muscles (electromyogram, EMG), cardiac myocytes (electrocardiogram, ECG), or neurons in the brain (electroencephalogram, EEG).
Definition:
Refers to the ability of some cells to be electrically excited resulting in the generation of
action potentials. Neurons, muscle cells (skeletal, cardiac, and smooth), and some endocrine cells (e.g., insulin-releasing pancreatic
β cells) are excitable cells.
See also:
Resting Membrane Potential - Introduction
Definition:
The voltage difference across a cell plasma membrane in the resting or quiescent state. It is also simply referred to as the resting potential (
Vrest). The value of the resting membrane potential varies from cell to cell. Depending on the cell type, it can range from −90 mV to −20 mV.
For example,
Vrest is −90 mV in skeletal and cardiac muscle cells as well as in astrocytes. In a typical neuron,
Vrest is approximately −70 mV. In many non-excitable cells,
Vrest ranges from −60 to −50 mV. In photoreceptors,
Vrest is about −20 mV.
See also:
Resting membrane potential
Posted: Sunday, March 31, 2013
Last updated: Friday, August 28, 2015