Plant Source Foods
Chuong Pham-Huy, Bruno Pham Huy in Food and Lifestyle in Health and Disease, 2022
The gymnosperms are non-flowering or seed-producing plants such as Cycas, Pinus, Ginkgo in which ovules are not enclosed by any ovary wall; hence they are called naked-seeded plants. In angiosperms or flowering plants, the male sex organs (stamen) and female sex organs (pistil) are borne in a same flower. The anther produces pollen grains (male gametophyte). The pistil consists of an ovary enclosing one to many ovules. Within the ovule is the female gametophyte or embryo sac which contains the egg cell. The angiosperms are divided into two classes: the monocotyledons or monocots (seed with a single cotyledon or one embryonic leaf) and the dicotyledons or dicots (seed having two cotyledons or two embryonic leaves) (2). They range in size from tiny, aquatic Wolffia to tall trees of Eucalyptus (over 100 m). Plants provide us with food, fodder, fuel, medicines, and several other commercially important products (2).
Does Personhood Begin at Conception?
Christopher Kaczor in The Ethics of Abortion, 2023
This is a biological question, and we could quote here, page after page, numerous biologists, scientists, and physicians who have provided clear answers to this question. In the interest of space, let's consider only three texts (noted earlier by Lee 1996):The formation, maturation, and meeting of a male and female sex cell are all preliminary to their actual union into a combined cell, or zygote, which definitely marks the beginning of a new individual. This penetration of the ovum by spermatozoon, and the coming together and pooling of their respective nuclei, constitutes the process of fertilization.(Arey 1974, p. 55)the fertilization of an ovum by a sperm. The expression “fertilized ovum” refers to the zygote.(Moore 1983, p. 9)Embryonic life commences with fertilization, and hence the beginning of that process may be taken as the point of departure of stage I.(Larsen 1993, p. 19)
The Many Faces of Neoplasia
Jeremy R. Jass in Understanding Pathology, 2020
The majority of cancers may be ascribed to one of the three cancer types: carcinoma, sarcoma and lymphoma. This classification has an embryological basis. When an ovum is fertilised by a sperm, the result is a single cell or zygote (from the Greek word meaning joined together). The zygote carries the potential to form all the cells of the body. At first this totipotential cell divides to form two, then four, then eight cells and so on. At this early stage the ball of cells may be disaggregated and could in theory form a clone of two, four, eight or sixteen identical individuals. The embryo starts to form when groups of cells become committed to a particular line of tissue differentiation, of which there are three major types. Ectoderm forms the skin and nervous system, endoderm forms the epithelial lining of internal hollow organs (e.g. gut) and associated glandular organs (e.g. liver and pancreas), and mesoderm forms all the rest (muscle, bone, bone marrow, cartilage, lymphoid system and connective tissue). As a general rule carcinomas arise from ectoderm or endoderm, whereas sarcomas and lymphomas arise from mesoderm.
Aluminum reproductive toxicity: a summary and interpretation of scientific reports
Published in Critical Reviews in Toxicology, 2020
Robert A. Yokel
The development of an oocyte begins as a primordial germ cell. Early in embryonic development these cells migrate into the future site of the ovaries, undergo meiotic cell division, and multiply, resulting in primary oocytes (primordial follicle) within the ovary. Their development is arrested until puberty, when follicle stimulating hormone (FSH) produced by the pituitary gland stimulates some to begin to mature, developing through follicle stages (primary, secondary, and if fertilized tertiary (Graafian) follicles), in the process of folliculogenesis. Most die (atresia) during these stages. During the resumption of cell division, the oocyte’s nucleus (germinal vesicle) breaks down and the first polar body (that forms concomitantly during oocyte division) is extruded. Follicle cells secrete and release estrogen that feeds back to the pituitary gland to decrease FSH release and increase luteinizing hormone (LH) release. This causes the follicle to rupture, resulting in release of the egg (ovulation), that migrates into the fallopian tubes where it can be fertilized by sperm. The ruptured follicle forms a corpus luteum, a transitory endocrine organ that secretes estrogen and progesterone. The latter feeds back to the pituitary gland to decrease LH release. The fertilized oocyte forms a mature egg cell (ovum). When the oocyte and sperm chromosomes combine, it becomes a zygote, which divides as it migrates into the uterus, creating the pregnant (gravid) state.
Progestogens and pregnancy loss
Published in Climacteric, 2018
H. J. A. Carp
In in vitro fertilization (IVF), there may be inhibition of the luteinizing hormone surge by the supraphysiologic doses of estrogen15. Additionally, at ovum pick-up, a number of granulosa cells, which were destined to form luteal (progesterone-secreting) cells are also aspirated. Hence, estrogen and progesterone levels drop, thus leading to decreased implantation and pregnancy rates16. A significant negative correlation has been reported between both pre-ovulatory estradiol concentrations and day-16 progesterone levels and the concentration of cytosolic progesterone receptors17. Hence, natural cycles have been characterized by low levels of cytosolic estradiol receptors and high levels of cytosolic progesterone receptors, whereas the concentrations of both receptors were greatly reduced in stimulated cycles. Due to receptor abnormalities, the endometrium can be progesterone-deficient even if plasma progesterone levels are normal18.
Thymoquinone ameliorates obesity-induced metabolic dysfunction, improves reproductive efficiency exhibiting a dose-organ relationship
Published in Systems Biology in Reproductive Medicine, 2019
Seba Harphoush, Guoqing Wu, Gao Qiuli, Margaret Zaitoun, Maissam Ghanem, Yonghui Shi, Guowei Le
The left ovary in three non-reproductive females each group and a part of left mammary gland in six lactating females each group was fixed in Paraformaldehyde 4% in PBS for 24 h and embedded in paraffin. Hematoxylin and Eosin (HE) staining was performed on 5 mm serial to analyze the histopathological changes of ovarian follicle cells and mammary alveolar lumens. HE sections were observed with a CX31 RTSF microscope (Olympus Corporation, Tokyo, Japan). In lactating mammary glands, alveolar Lumens area was measured using Image-J NIH software (McGinley and Thompson 2011). In non-reproductive females’ ovaries, follicular stages were classified to early stage follicles (primary follicles; secondary follicles; antral follicles) and later stage follicles (Graafian follicles; corpus luteum) according to the Erickson’s classification (Williams and Erickson 2012). Graafian follicle: the oocyte is surrounded by cumulus oophorus cells, and is adjacent to a single large antrum (an ovum develops prior to ovulation). Corpus luteum: It is the remains of the ovarian follicle that has released a mature ovum during a previous ovulation. Only later stage follicles were observed and counted per one ovary to estimate ovulation.
Related Knowledge Centers
- Ploidy
- Sexual Reproduction
- Sperm
- Gamete
- Reproduction
- Anisogamy
- Motility
- Oogamy
- Oospore
- Fertilisation