Ovule structure

However, there are a few features that now appear to be more stable than previously thought, especially in ovule structure, such as nucellus thickness and number of integuments. New studies have continuously reinforced this picture (Endress et al.,... 

Endress, 2003, 2010 Endress and Matthews, 2006). Additional ovule structural features have also recently been found to be of macrosystematic significance (relative thickness of inner and outer integument, Endress and Matthews, 2006). 

Provided these two processes are in phase, the conditions are then optimal for fertilisation, proliferation of the zygote to form the blastocyst, implantation of the latter and maintenance of pregnancy. Before ovulation, the development of the ovum and hormone secretion take place in a single structure, the follicle. 

Induction of ovulation, stimulation of spermatogenesis in men HCG family PTomo sapiens] GI 15277242 PID gl5277242 Crystal structure of human chorionic gonadotropin PDB ID IHRP... 

Progesterone ranks with estradiol as one of the key hormones that controls the reproductive cycle in the mammalian female. Progesterone, synthesized by a structure on the ovary that forms immediately after ovulation known as the corpus luteum, inhibits subsequent ovulation until the next cycle. Increased levels of progesterone are essential in... 

The corpus luteum arises from the ruptured follicle and secretes progesterone, which has an important role in the estrous or menstrual cycle. Luteal progesterone is also required to maintain early pregnancy in most mammalian species, including humans (Csapo Pulkkinen, 1978). Therefore, establishment and maintenance of normal corpora luteaare essential for normal reproductive function. However, with the exception of evaluations to establish their presence or absence, these structures are not evaluated in routine testing. Increased rates of follicular atresia and oocyte toxicity may lead to premature menopause in humans. Altered follicular development, failure to ovulate or altered corpus luteum formation and function can disrupt cyclicity, reduce fertility and interfere with normal sexual behaviour. Therefore, significant increases in the rate of follicular atresia, evidence of oocyte toxicity, interference with ovulation or altered corpus luteum formation or function should be considered adverse effects. 

OvULARY The structure in the pistil of seed plants which produces the ovules the ovary. 

Placenta That part of the carpel bearing ovules or in animals the structure which is attached to the parent organism and obtains food for an immature individual, i.e. an haustorium produced by some immature animals and attached to the parent organism. 

Pollination an important step in the reproduction of seed plants—the transfer of pollen grains (male gametes) from the stamens (male organs) to the plant carpel, the structure that contains the ovule (female gamete). The receptive part of the carpel is called a stigma in the flowers of angiosperms (flowering plants). 

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