embryo

DEFINITION:

1. In plants, the element of the seed that develops into a new individual.

2. In animals, those derivatives of the fertilized ovum that eventually become the offspring, during their period of most rapid development, i.e., after the long axis appears until all major structures are represented.

3. In humans, the developing organism from the end of the second week after fertilization to the end of the eighth week.

fetus

DEFINITION:

A developing human from usually three months after conception to birth.

ovum

DEFINITION:

1. An egg; the female reproductive cell which, after fertilization, becomes a zygote that develops into a new member of the same species.
2. The human ovum: a round cell about 0.1 mm. in diameter, produced in the ovary, where there is deposited around it a noncellular covering. It consists of protoplasm which contains some yolk, enclosed by a thin cell wall. There is a large nucleus, within which is a nucleolus. By extension, the word is also used to designate any early stage of the conceptus, when the embryo itself constitutes a tiny and insignificant part of the whole.

spermatozoon

DEFINITION:

A mature male germ cell, the specific output of the testes. It is the generative element of the semen which serves to fertilize the ovum, and contains the genetic information to be transmitted to the zygote by the male. It consists of a head (or nucleus), a neck, a middle piece, and a tail with an end piece. Spermatozoa, formed in the seminiferous tubules, are derived from spermatogonia, which first develop into spermatocytes, which, in turn, undergo meiosis to produce spermatids; the spermatids then differentiate into spermatozoa. Called also sperm.

cessation

DEFINITION:

A temporary or final ceasing (as of action).

menses

DEFINITION:

The monthly flow of blood from the genital tract of women.

nausea

DEFINITION:

An unpleasant sensation, vaguely referred to the epigastrium and abdomen, and often culminating in vomiting.

pigmentation

DEFINITION:

The deposition of coloring matter; the coloration or discoloration of a part by a pigment.

abdomen

DEFINITION:

1. The part of the body of a mammal between the thorax and the pelvis; belly.


2. The cavity of this part of the body containing most of the digestive organs.

fetal

DEFINITION:

Of or pertaining to a fetus; pertaining to in utero development after the embryonic period.

fetal

DEFINITION:

Of or pertaining to a fetus; pertaining to in utero development after the embryonic period.

fetus

DEFINITION:

A developing human from usually three months after conception to birth.

X-ray

DEFINITION:

To examine, treat, or photograph with X rays. X ray:

1. Any of the electromagnetic radiations of the same nature as visible radiation but of an extremely short wavelength less than 100 angstroms that is produced by bombarding a metallic target with fast electrons in vacuum or by transition of atoms to lower energy states and that has the properties of ionizing a gas upon passage through it, of penetrating various thicknesses of all solids, of producing secondary radiations by impinging on material bodies, of acting on photographic films and plates as light does, and of causing fluorescent screens to emit light.

2. A photograph obtained by

use of X rays.

ultrasound

DEFINITION:

1. Mechanical radiant energy with a frequency greater than 20,000 hertz (cycles per second).

2. Ultrasonography.

Doppler ultrasound - That in which the shifts in frequency between emitted ultrasonic waves and their echoes are used to measure the velocities of moving objects, based on the principle of the Doppler effect. The waves may be continuous or pulsed; the technique is frequently used to examine cardiovascular blood flow.