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Glossary of Physiology Terms
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There are 14 glossary search results for:   ARC




Definition:
An early sexual maturation stage, occurring 1 or 2 years before the onset of puberty, during which the zona reticularis of the adrenal cortex releases increased levels of dehydroepiandrosterone (DHEA) and androstenedione. These adrenal androgens are ultimately responsible for the appearance of pubic and axillary hair, increased oil production by facial skin, acne, and distinct adult body odor.

Related glossary terms/phrases:
Menarche
Pubarche
Thelarche



Definition:
Onset of menstruation.

Related glossary terms/phrases:
Adrenarche
Pubarche
Thelarche



Definition:
Development of axillary and pubic hair during puberty.

Related glossary terms/phrases:
Adrenarche
Menarche
Thelarche



Definition:
Plasma membrane of a muscle cell. It is also referred to as myolemma.

Related glossary terms/phrases:
Myolemma



Definition:
Cytoplasm of a muscle cell. It is also referred to as myoplasm.

Related glossary terms/phrases:
Myoplasm



Definition:
Development of breasts as an early event during female puberty.

Related glossary terms/phrases:
Adrenarche
Menarche
Pubarche



Definition:
The A band is the region of a striated muscle sarcomere that contains myosin thick filaments. In fact, the A band is the entire length of the thick filament of the sarcomere. Its length is approximately 1 μm. The center of the A band is located at the center of the sarcomere (M line).

Related glossary terms/phrases:
H zone
I band
M line
Z disk



Definition:
The H zone is in the center of the A band where there is no overlap between the thick and the thin filaments. Therefore, in the H zone, the filaments consist only of the thick filament. The H zone becomes smaller as the muscle contracts and the sarcomere shortens. The center of the H zone is at the M line, which is also at the center of the sarcomere.

Related glossary terms/phrases:
A band
I band
M line
Z disk



Definition:
The I band is the region of a striated muscle sarcomere that contains thin filaments. This region is closest to the Z disk, and is the lightest region of the sarcomere when viewed in under the light or electron microscope. The I band is occupied by the thin filaments only. Each Z disk runs through the middle of the I band. Therefore, half of each I band belongs to one sarcomere, and the other half belongs to the neighboring sarcomere. The I band shortens as the muscle contracts and the sarcomere shortens.

Related glossary terms/phrases:
A band
H zone
M line
Z disk



Definition:
In striated muscle sarcomere, the M line is the attachment site for the thick filaments. The M line is in the center of the A band and, thus, it is in the center of the sarcomere.

Related glossary terms/phrases:
A band
H zone
I band
Z disk



Definition:
Chemical warfare agent belonging to sulfur (or sulphur) mustards. Causes severe chemical burns and water blisters (i.e., it is a vesicant). It is cytotoxic, mutagenic, and carcinogenic.

Other resources:
Sulfur mustard (Wikipedia)



Definition:
Plasma membrane of a muscle cell. It is also referred to as sarcolemma.

Related glossary terms/phrases:
Sarcolemma



Definition:
Cytoplasm of a muscle cell. It is also referred to as sarcoplasm.

Related glossary terms/phrases:
Sarcoplasm



Definition:
The Z disk (or Z line) defines the boundaries of a muscle sarcomere. Two adjacent Z disks along the myofibril mark the boundaries of a single sarcomere. The Z disks are the attachment sites for the thin filaments. Therefore, from each Z disk, thin filaments extend to two neighboring sarcomeres. When a muscle fiber contracts, the Z disks of a sarcomere move closer together (i.e., the sarcomere also shortens).

Related glossary terms/phrases:
A band
H zone
I band
M line









Posted: Sunday, March 31, 2013
Last updated: Friday, August 28, 2015