phase

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phase

 [fāz]
1. one of the aspects or stages through which a varying entity may pass.
2. In physical chemistry, any physically or chemically distinct, homogeneous, and mechanically separable part of a system.
phase 0 in cardiac physiology, the phase representing the upstroke of the action potential, in which rapid depolarization occurs after the cell reaches or is driven to threshold potential. It is the result of the opening of fast sodium channels and calcium channels.
phase 1 in cardiac physiology, the initial rapid repolarization phase of the action potential, caused by the closure of the fast sodium channels and an exodus of potassium from the cell.
phase 2 in cardiac physiology, the phase representing the plateau of the action potential, which contributes to the refractory period of the heart; there is a slow entry of calcium into the cell. It is the result of a balance between inward and outward currents and is particularly long in Purkinje and ventricular cells.
phase 3 in cardiac physiology, the terminal rapid repolarization phase of the action potential; it begins with the closing of the slow channels, resulting in an exodus of potassium from the cell and the activation of the sodium-potassium pump. The result is reestablishment of the normal resting potential.
phase 4 in cardiac physiology, the phase representing electrical diastole, i.e. the time between action potentials. It is the resting phase of the electrical cardiac cycle and is steadily maintained in nonpacemaker cells. In pacemaker cells, the membrane potential is normally reduced slowly until threshold potential is reached; if there is an outside stimulus, it may be driven down more rapidly.
continuous phase in a heterogeneous system, the component in which the disperse phase is distributed, corresponding to the solvent in a true solution. See also colloid.
disperse phase the discontinuous portion of a heterogeneous system, corresponding to the solute in a true solution.
G1 phase a part of the cell cycle during interphase, lasting from the end of cell division (the M phase) until the start of DNA synthesis (the S phase).
G2 phase a relatively quiescent part of the cell cycle during interphase, lasting from the end of DNA synthesis (the S phase) until the start of cell division (the M phase).
M phase the part of the cell cycle during which mitosis occurs; subdivided into prophase, metaphase, anaphase, and telophase.
S phase a part of the cell cycle near the end of interphase, during which DNA is synthesized; it comes between the G1 and G2 phases.

phase

(fāz),
1. A stage in the course of change or development.
See also: stage, period.
2. A homogeneous, physically distinct, and separable portion of a heterogeneous system; for example, a mixture of oil, gum, and water are three phases of an emulsion.
See also: stage, period.
3. The time relationship between two or more events.
See also: stage, period.
4. A particular part of a recurring time pattern or wave form.
See also: stage, period.
[G. phasis, an appearance]

phase

(fāz)
1. one of the aspects or stages through which a varying entity may pass.
2. in physical chemistry, any physically or chemically distinct, homogeneous, and mechanically separable part of a system.pha´sic

erythrocytic phase  that phase in the life cycle of a malarial plasmodium in which the parasites multiply in the red blood cells.
five phases  in traditional Chinese medicine, a set of dynamic relations (designated earth, metal, water, wood, and fire) that can be used to categorize relationships among phenomena.
follicular phase  the first half of the human menstrual cycle, lasting from cessation of menstrual flow to the surge of luteinizing and follicle-stimulating hormones at the start of the ovulatory phase.
G1 phase  a part of the cell cycle during interphase, lasting from the end of cell division (the M phase) until the start of DNA synthesis (the S phase).
G2 phase  a relatively quiescent part of the cell cycle during interphase, lasting from the end of DNA synthesis (the S phase) until the start of cell division (the M phase).
luteal phase  the third phase of the human menstrual cycle, beginning with ovulation and ending, in the absence of fertilization, with the menstrual phase.
M phase  the part of the cell cycle during which mitosis occurs; subdivided into prophase, metaphase, anaphase, and telophase.
menstrual phase  the fourth phase of the human menstrual cycle, following the luteal phase in the absence of fertilization. The corpus luteum regresses and is shed through menstruation and growth begins for the ovarian follicle, leading to the next follicular phase.
ovulatory phase  the second phase of the human menstrual cycle, encompassing the surges of luteinizing and follicle-stimulating hormones, and ovulation; it is followed by the luteal phase.
S phase  a part of the cell cycle, near the end of interphase, during which DNA is synthesized; between the G1 and G2 phases.

phase

(fāz)
n.
1. A characteristic form, appearance, or stage of development that occurs in a cycle.
2. A discrete homogeneous part of a material system that is mechanically separable from the rest, as is ice from water.
3. Any of the forms or states, solid, liquid, gas, or plasma, in which matter can exist, depending on temperature and pressure.
4. A distinct part in a course or development, as of a disease.
v.
To introduce, one stage at a time.

phase

[fāz]
Etymology: Gk, phasis, appearance
in a periodic function, such as rotational or sinusoidal motion, the position relative to a particular part of the cycle.

phase

(1) One of a set of successive stages in a sequence, such as a step in the progression of a therapy from early testing in humans to postmarket evaluation, usually divided into four (or five) phases.
(2) A stage in the conduct of a clinical trial; because of the potential for confusion of various terms—phase, stage, period—epoch is preferred.

phase

Medtalk A step in a process or cycle. See Acceleration phase, Burned-out phase, Chronic phase, Conceptive phase, Delayed sleep phase, Initial phase, Lag phase, Oepidal phase, Plateau phase, Prevascular phase, Proliferative phase, Recovery phase, Resting phase, Secretory phase, Shock phase, Stance phase, Swing phase, Take-off phase.

phase

(fāz)
1. A stage in the course of change or development.
2. A homogeneous, physically distinct, and separable portion of a heterogeneous system; e.g., oil, gum, and water are three phases of an emulsion.
3. The time relationship between two or more events.
4. A particular part of a recurring time pattern or wave form.
See also: stage, period
[G. phasis, an appearance]

phase 

The state of vibration of a light wave at a particular time. Light waves vibrating with the same frequency are said to be in phase if their peaks and troughs occur at the same time; otherwise they are said to be out of phase and one wave lags or precedes another by a phase difference (e.g. a fraction of a wavelength, or one wavelength, or a number of wavelengths). For waves exactly out of phase the phase difference is half a wavelength and for waves exactly in phase it is 0. See interference; wavelength.

phase

(fāz)
1. Stage in course of change or development.
2. Homogeneous, physically distinct, and separable portion of a heterogeneous system.
3. Time relationship between two or more events.
4. Particular part of a recurring time pattern or wave form.
[G. phasis, an appearance]

phase

1. one of the aspects or stages through which a varying entity may pass.
2. In physical chemistry, a component that is homogeneous of itself, bounded by an interface, and mechanically separable from other phases of the system.

continuous phase
in a heterogeneous system, the component in which the disperse phase is distributed, corresponding to the solvent in a true solution.
disperse phase
the discontinuous portion of a heterogeneous system, corresponding to the solute in a true solution.
phase feeding
a poultry feeding strategy based on varying the amount and kind of feed fed with varying egg production levels, body weight, age, environmental temperature and cost of feed ingredients.
phase plate
a critical component of a phase microscope.
phase transition temperature
temperature, usually between 30°C and 40°C, at which biological membranes change from a rigid gel phase to a thinner, more fluid phase.

Patient discussion about phase

Q. What is the second phase of alcohol rehab? I guess the first one is well known... admitting you are addicted, but then what?

A. anybody??? advises about the second phase of rehab??

Q. what is the window phase for HIV?

A. The 'window' period for HIV infection describes the strong immune defense that reduces the number of viral particles in the blood stream, marking the start of the infection's clinical latency stage. Clinical latency can vary between two weeks and 20 years. During this early phase of infection, HIV is active within lymphoid organs, where large amounts of virus become trapped in the follicular dendritic cells. The surrounding tissues that are rich in CD4+ T cells may also become infected, and viral particles accumulate both in infected cells and as free virus. Individuals who are in this phase are still infectious.

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