1. A structure at the end of a sperm cell that releases enzymes to digest the cell membrane of an egg, enabling the sperm to penetrate and enter the egg for fertilization.
2. Body at the apex of spermatozoon; apical body; perforatorium.
3. A cytoplasmic cap-like structure on the front of a spermatozoan (sperm; a mature male germ cell).
The entire body of any actinozoan, whether simple, as in the sea-anemones, or composed of several zoöids, as in most corals.
1. A developmental anomaly consisting of imperfect development of reproductive organs, usually with the protrusion of the intestines through an imperfectly developed abdominal wall.
2. A congenital malformation characterized by the absence or defective formation of the genitals and protrusion of the intestines through an incompletely developed abdominal wall.
A fetus with a congenital malformation characterized by the absence or defective formation of the genitals and a protrusion of the intestines through an incompletely developed abdominal wall.
1. Any chromosome or chromosome fragment other than a normal A-chromosome.
2. A chromosome that is different from the rest, usually the sex chromosome.
A male-limited chromosome; literally, a male body.
asoma, asomus (s) (noun)
; asomata (pl)
Having an incomplete body: Dr. Anderson, the obstetrician, who always provides medical care to women during pregnancy and childbirth, presented bad news to the pregnant woman as he told her that she had an unborn baby with an asoma, which is an incompletely developed and nonfunctional body with a deformed head and body.
The condition of containing only embryonic tissues.
asomatognosia (s) (noun)
, asomatognosias (pl)
1. Lack of awareness of the condition of all or part of a person's body: Gerard had an asomatognosia which meant that he didn't realize that his paralyzed arm belonged to him.
2. The inability of a person to recognize what is happening to parts of his or her body: Maggie had a condition of asomatognosia which made it impossible for her to realize what was happening to various parts of her body because of her impaired (mentally unfit) brain functions.
asomatophyte (s) (noun)
, asomatophytes (pl)
A plant in which there is no distinction between body and reproductive cells: For Ben's research project in botany, he was hoping to catalogue several examples of asomatophytes from the local park.
1. The sensation that an amputated portion of the body is still present.
2. A patient's lack of awareness of a bodily defect, as in the phantom limb of an amputee.
A reference to autosomatognosis or the sensation that a person has that an amputated portion of his or her body is still present.
A chromosome other than a sex chromosome (one that determines sex), normally occurring in pairs in somatic cells and singly in gametes in spermatozoa.
The sum total of all sponge tissues lying within the outer cover or ectosome.
chromosome (s) (noun)
, chromosomes (pl)
1. Any of the threadlike structures in the nucleus of a cell that function in the transmission of genetic information.
Each chromosome consists of a double strand of DNA attached to proteins called histones.
The genes, which contain the genetic material that controls the inheritance of traits, are arranged in a linear pattern along the length of each DNA strand.
Each species has a characteristic number of chromosomes in each somatic cell. In humans, there are forty-six chromosomes, including twenty-two homologous pairs of autosomes and one pair of sex chromosomes.
One member of each pair is derived from each parent.
2. Etymology: from German Chromosom
, coined in 1888 by the German anatomist, Wilhelm von Waldeyer-Hartz (1836-1921), from Greek khroma
, "color" + soma
, "body". This term was coined because the structures contain a substance that stains readily with basic dyes.