Reproduction and development

2021 ◽  
pp. 657-724
Keyword(s):  
Sexual Differentiation ◽  
Reproductive Function ◽  
Body Cavity ◽  
Cavity Formation ◽  
Reproductive Systems ◽  
Male And Female ◽  
Organ Systems ◽  
Major Organ ◽  
Males And Females ◽  
Human Embryology

‘Reproduction and development’ opens with the anatomy of the pelvis and perineum, the male and female genital systems, and sexual differentiation, before moving onto reproductive function: the production of gametes in males and females, pregnancy, lactation, the effects of age on reproductive status, and the pharmacology of sex hormones. The other main consideration of this chapter is human embryology, guiding the reader through from fertilization and implantation, gastrulation and germ layer establishment, embryonic folding and body cavity formation, limb, head, and neck development, and development of the major organ systems (including the cardiovascular, gastrointestinal, respiratory, renal, and reproductive systems).

The internal anatomy of Typhlops schneider (Reptilia)

1960 ◽  
Vol 8 (2) ◽  
pp. 181 ◽  
Author(s):  
J Robb
Keyword(s):  
Connective Tissue ◽  
Reproductive Organs ◽  
Body Cavity ◽  
The Body ◽  
The Other ◽  
Internal Anatomy ◽  
Reproductive Systems ◽  
Male And Female ◽  
Connective Tissue Sheath ◽  
First Time

The internal anatomy of Typhlops shows a number of interesting features which support the hypothesis that the typhlopids are wrongly classified among the Ophidia, and that they should either be given subordinal rank, equivalent to the Sauria and the Serpentes, or be made an infra-order of the Sauria. The alimentary, vascular, respiratory, and reproductive systems are described in detail for the first time. The most striking peculiarities occur in the respiratory and reproductive systems. Unlike most snakes, Typhlops has two functional lungs, one occupying most of the anterior third of the body cavity, and the other smaller one lying immediately behind it. All the pulmonary blood vessels are well developed. The male reproductive organs are solid, grooved, protrusible structures, each of which is contained within a connective tissue sheath in the postanal region. These organs are unlike the hemipenes of any snake or lizard of which a description can be found. Both male and female animals possess a large cloaca1 gland in the postanal region. There are also several uncommon features in the alimentary and vascular systems.

THE SECONDARY SEX CHARACTERS AND REPRODUCTIVE BEHAVIOR OF GONADECTOMIZED STICKLEBACKS TREATED WITH METHYL TESTOSTERONE

1963 ◽  
Vol 41 (4) ◽  
pp. 611-628 ◽  
Author(s):  
Evelyn Hui Wai ◽  
William S. Hoar
Keyword(s):  
Reproductive Behavior ◽  
Body Cavity ◽  
The Body ◽  
Combined Effects ◽  
Male And Female ◽  
Long Day ◽  
Building Behavior ◽  
Males And Females ◽  
Secondary Sex Characters ◽  
Behavior Characteristic

Treatment of intact juvenile or gonadectomized adult male and female stickle-backs with methyl testosterone, either by immersion in dilute solutions or by implantation of pellets into the body cavity, induces male secondary sex characters. The effect, as quantified by measurements of the height of the brush border tubules in the mesonephros, is the same in both sexes and reaches a maximum in 3 to 4 weeks. Both the gonadectomized males and females develop prespawning aggressive and territorial behavior if maintained 4 or 5 weeks under long-day photoperiods (16-hour day alternating with 8-hour darkness). Such behavior does not appear under a short photoperiod. The administration of methyl testosterone does not intensify aggressive behavior in either the 8-hour or 16-hour photoperiod fish. The combined effects of long photoperiods and methyl testosterone induces nest-building behavior (characteristic of normal breeding males) in 50% to 60% of the castrated males and about 6% of the gonadectomized females. The behavior of the treated males is qualitatively and quantitatively similar to naturally matured fish but that of the females shows differences. Although male sexual behavior may also be induced in androgen treated castrates it has not been observed in the females under comparable experimental procedures.

Chromatin dynamics associated with sexual differentiation in a UV sex determination system

2020 ◽  
Author(s):  
Josselin Gueno ◽  
Simon Bourdareau ◽  
Guillaume Cossard ◽  
Olivier Godfroy ◽  
Agnieszka Lipinska ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sex Determination ◽  
Histone Modifications ◽  
Sex Chromosomes ◽  
Sexual Differentiation ◽  
Chromatin State ◽  
State Transitions ◽  
Male And Female ◽  
Chromatin States ◽  
Males And Females

SummaryIn many eukaryotes, such as dioicous mosses and many algae, sex is determined by UV sex chromosomes and is expressed during the haploid phase of the life cycle. In these species, the male and female developmental programs are initiated by the presence of the U- or V-specific regions of the sex chromosomes but, as in XY and ZW systems, phenotypic differentiation is largely driven by autosomal sex-biased gene expression. The mechanisms underlying sex-biased transcription in XY, ZW or UV sexual systems currently remain elusive. Here, we set out to understand the extent and nature of epigenomic changes associated with sexual differentiation in the brown alga Ectocarpus, which has a well described UV system. Five histone modifications, H3K4me3, H3K27Ac, H3K9Ac, H3K36me3, H4K20me3, were quantified in near-isogenic male and female lines, leading to the identification of 13 different chromatin states across the Ectocarpus genome that showed different patterns of enrichment at transcribed, silent, housekeeping or narrowly-expressed genes. Chromatin states were strongly correlated with levels of gene expression indicating a relationship between the assayed marks and gene transcription. The relative proportion of each chromatin state across the genome remained stable in males and females, but a subset of genes exhibited different chromatin states in the two sexes. In particular, males and females displayed distinct patterns of histone modifications at sex-biased genes, indicating that chromatin state transitions occur preferentially at genes involved in sex-specific pathways. Finally, our results reveal a unique chromatin landscape of the U and V sex chromosomes compared to autosomes. Taken together, our observations reveal a role for histone modifications in sex determination and sexual differentiation in a UV sexual system, and suggest that the mechanisms of epigenetic regulation of genes on the UV sex chromosomes may differ from those operating on autosomal genes.

STUDIES OF SEXUAL DIFFERENTIATION OF SHEEP

1978 ◽  
Vol 89 (1) ◽  
pp. 182-189 ◽  
Author(s):  
P. R. Wilson ◽  
M. F. Tarttelin
Keyword(s):  
Blood Plasma ◽  
Sexual Differentiation ◽  
Female Offspring ◽  
Plasma Testosterone ◽  
Plasma Samples ◽  
Normal Appearance ◽  
Control Male ◽  
Control Female ◽  
Male And Female ◽  
Males And Females

ABSTRACT Forty ewes were given intramuscular injections of testosterone cypionate (200 mg) on each of the 20th, 27th and 40th days of gestation. This treatment ensured foetal exposure to testosterone from day 20 to day 65. Forty untreated ewes acted as controls. At birth, pre-natally androgenised male lambs were anatomically normal, but similarly treated female offspring displayed complete external genital masculinisation including the presence of a prepuce, penis and scrotum and the absence of an external vulval opening. No male gonads were present. Internally, the female lambs possessed ovaries, uteri, cervices and vagina of normal appearance. Two-weekly blood plasma samples were withdrawn from 10 androgenised and 6 control female offspring and 8 androgenised and 8 control male offspring from 4–30 weeks of age. Testosterone levels in males and LH levels in males and females were measured by radioimmunoassays. Analyses of variance showed that post-natal plasma LH levels in pre-natally androgenised lambs (male and female) were significantly depressed (P < 0.001), and that plasma testosterone concentrations in pre-natally androgenised males were subsequently depressed (P < 0.001). These results suggested that pre-natal androgenisation impaired hypothalamic hypophysiotrophic and/or pituitary function during the first 30 weeks of post-natal life which resulted either directly, or indirectly via reduced LH output, in a suppression of testosterone production by the testes.

THE MORPHOLOGY OF THE MALE AND FEMALE REPRODUCTIVE SYSTEMS OF THE MIDGE, CHIRONOMUS PLUMOSUS L.

1962 ◽  
Vol 40 (2) ◽  
pp. 199-229 ◽  
Author(s):  
Rita J. D. Wensler ◽  
J. G. Rempel
Keyword(s):  
Reproductive System ◽  
Ejaculatory Duct ◽  
Reproductive Function ◽  
Accessory Gland ◽  
Reproductive Systems ◽  
Female Adult ◽  
Male And Female ◽  
Chironomus Plumosus ◽  
Nematode Worm

In both the male and female adult midge, the posterior three abdominal segments are modified for the reproductive function, and the musculature of these segments is modified accordingly. Main features of the male internal reproductive system are testes consisting of one sperm tube each, in which spermatogenesis is complete, and a glandular ejaculatory duct of four sections. The muscles of the posterior pregenital segments are modified for torsion. The muscles of the terminalia are described. Those of the ninth segment are greatly modified for the genital function. The female has numerous three-chambered polytrophic ovarioles extending radially from a common central egg passage in the ovary, and there is a single accessory gland. The muscles of the female terminalia are described. The reproductive system of several specimens parasitized by a nematode worm is discussed.

Observation on the breeding biology of Polypedates teraiensis (Dubois, 1987) (Amphibia: Rhacophoridae)

2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.
Keyword(s):  
Sexual Dimorphism ◽  
Breeding Season ◽  
Sound Production ◽  
Reproductive Function ◽  
Breeding Biology ◽  
Tree Frog ◽  
University Campus ◽  
Morphometric Measurements ◽  
Advertisement Calls ◽  
Males And Females

The breeding biology of tree frog, Polypedates teraiensis was studied during the breeding season at Mizoram University Campus. It was found that sound production by male during the breeding season was primarily a reproductive function and advertisement calls attract females to the breeding areas and announce other males that a given territory is occupied. The aim of this study was to provide the detailed information on the breeding behaviour and the advertisement calls of Polypedates teraiensis. The morphometric measurements of the amplecting pairs (males and females) for sexual dimorphism along with clutch sizes were also studied.

GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS:

1968 ◽  
Vol 58 (4) ◽  
pp. 600-612 ◽  
Author(s):  
Robert Boyd ◽  
Donald C. Johnson
Keyword(s):  
Ascorbic Acid ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Female Rat ◽  
Feedback Effects ◽  
Male And Female ◽  
Prostate Weight ◽  
Male And Female Rats ◽  
Males And Females ◽  
Normal Males

ABSTRACT The effects of various doses of testosterone propionate (TP) upon the release of luteinizing hormone (LH or ICSH) from the hypophysis of a gonadectomized male or female rat were compared. Prostate weight in hypophysectomized male parabiotic partners was used to evaluate the quantity of circulating LH. Hypophyseal LH was measured by the ovarian ascorbic acid depletion method. Males castrated when 45 days old secreted significantly more LH and had three times the amount of pituitary LH as ovariectomized females. Administration of 25 μg TP daily reduced the amount of LH in the plasma, and increased the amount in the pituitary gland, in both sexes. Treatment with 50 μg caused a further reduction in plasma LH in males, but not in females, while pituitary levels in both were equal to that of their respective controls. LH fell to the same low level in partners of males or females receiving 100 μg TP. When gonadectomized at 39 days, males and females had the same amount of plasma LH, but males had more stored hormone. Pituitary levels were unchanged from controls following treatment with 12.5, 25 or 50 μg TP daily, but plasma values dropped an equal amount in both sexes with the latter two doses. Androgenized males or females, gonadectomized when 39 days old, were very sensitive to the effects of TP and plasma LH was significantly reduced with 12.5 μg daily. Pituitary LH in androgenized males was higher than that of normal males but was reduced to normal by small amounts of TP. The amount of stored LH in androgenized females was not different from that of normal females and it was unchanged by any dose of TP tested. Results are consistent with the conclusion that the male hypothalamic-hypophyseal axis is at least as sensitive as the female axis to the negative feedback effects of TP. Androgenization increases the sensitivity to TP in both males and females.

FEATURES OF FORMATION OF THE MAIN SYSTEMS AND ORGANS IN EARLY LARVAE OF MULLETS (LIZA AURATA, RISSO, 1810)

2017 ◽  
pp. 98-106
Author(s):  
Dariya Aleksandrovna Gavrilova ◽  
Maria Pavlovna Grushko
Keyword(s):  
Nervous System ◽  
Sample Selection ◽  
Early Ontogeny ◽  
Basal Cells ◽  
The Caspian Sea ◽  
Liza Aurata ◽  
Morphological Organization ◽  
Organ Systems ◽  
Major Organ ◽  
Well Differentiated

The aim of this work was to study peculiarities of mullet morphological organization during early ontogeny. Sample selection was made on board Caspian research and development Institute of Fisheries’ research vessel in period from June to September, 2015 in Russian waters of the Caspian Sea. Larvae aged 10 days could be characterized by heterochrony in the development of major organ systems. Nervous system and sense organs were well developed. The eyeball had all membranes well-differentiated, in the retina all the layers were formed. The olfactory fossae had cells of 3 types: olfactory receptor cells, supporting cells and basal cells. There was observed intensive formation of respiratory, cardiovascular, excretory and digestive systems. The early development of the nervous system and sensory organs of the larvae indicated adaptation of mullet to active life.

Gender Differences in Clothing Worn in Current Popular Comic Books

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Kyle Landon Jossy
Keyword(s):  
Gender Differences ◽  
Content Analysis ◽  
Comic Books ◽  
Book Industry ◽  
Comic Book ◽  
Lower Body ◽  
Female Characters ◽  
Male And Female ◽  
Males And Females

This study looked at how males and females were portrayed, based on the amount of skin shown in the clothing worn.  A Content analysis was performed on a sample of 20 randomly selected popular comics from the last 3 years.  Both male and female characters were rated on how much skin they showed in three clothing categories; neck line, sleeve length, and lower body.  Results showed that in all 3 categories, women consistently wore more revealing clothing.  The findings demonstraetd that the comic book industry is comparable to other forms of media, in the sexualization of female characters, by having them wear more revealing clothing.

Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)

2016 ◽  
Vol 88 (8) ◽  
pp. 713-830
Author(s):  
John H. Duffus ◽  
Michael Schwenk ◽  
Douglas M. Templeton
Keyword(s):  
Risk Assessment ◽  
Reproductive Biology ◽  
Environmental Risk ◽  
Environmental Risk Assessment ◽  
Primary Objective ◽  
Human Reproduction ◽  
Reproductive Systems ◽  
Teratogenic Effects ◽  
Male And Female ◽  
Medical Practitioners

Abstract The primary objective of this glossary is to give clear definitions for those who contribute to studies relevant to these disciplines, or who must interpret them, but are not themselves reproductive physiologists or physicians. This applies especially to chemists who need to understand the literature of reproductive and teratogenic effects of substances without recourse to a multiplicity of other glossaries or dictionaries. The glossary includes terms related to basic and clinical reproductive biology and teratogenesis, insofar as they are necessary for a self-contained document, particularly terms related to diagnosing, measuring, and understanding the effects of substances on the embryo, the fetus, and on the male and female reproductive systems. The glossary consists of about 1200 primary alphabetical entries and includes Annexes of common abbreviations and examples of chemicals with known effects on human reproduction and development. The authors hope that toxicologists, pharmacologists, medical practitioners, risk assessors, and regulatory authorities are among the groups who will find this glossary helpful, in addition to chemists. In particular, the glossary should facilitate the worldwide use of chemical terminology in relation to occupational and environmental risk assessment.

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