WDuring fertilization, a sperm must first fuse with the plasma membrane and then penetrate the female egg cell to fertilize it. Fusing to the egg cell usually causes little problem, whereas penetrating through the egg's hard shell or extracellular matrix can be more difficult. Therefore, sperm cells go through a process known as the acrosome reaction, which is the reaction that occurs in the acrosome of the sperm as it approaches the egg. The acrosome is a cap-like structure over the anterior half of the sperm's head.
WThe baculum is a bone found in the penis of many placental mammals. It is absent in the human penis, but present in the penises of other primates, such as the gorilla and chimpanzee. The os penis arises from primordial cells within soft tissues of the penis, and its formation is largely under the influence of androgens. The bone is located above the male urethra, and it aids sexual reproduction by maintaining sufficient stiffness during sexual penetration. The homologue to the baculum in female mammals is known as the baubellum or os clitoridis, a bone in the clitoris.
WBenign prostatic hyperplasia (BPH), also called prostate enlargement, is a noncancerous increase in size of the prostate gland. Symptoms may include frequent urination, trouble starting to urinate, weak stream, inability to urinate, or loss of bladder control. Complications can include urinary tract infections, bladder stones, and chronic kidney problems.
WCastration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchidectomy, and chemical castration uses pharmaceutical drugs to deactivate the testes. Castration causes sterilization ; it also greatly reduces the production of certain hormones, such as testosterone. Surgical castration in animals is often called neutering.
WThe cremasteric reflex is a superficial reflex observed in human males.
WEjaculation is the discharge of semen from the male reproductory tract as a result of an orgasm. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. In rare cases, ejaculation occurs because of prostatic disease. Ejaculation may also occur spontaneously during sleep. Anejaculation is the condition of being unable to ejaculate. Ejaculation is usually very pleasurable for men; dysejaculation is an ejaculation that is painful or uncomfortable. Retrograde ejaculation is the condition where semen travels backwards into the bladder rather than out the urethra.
WThe ejaculatory ducts are paired structures in male anatomy. Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and open into the urethra at the seminal colliculus. During ejaculation, semen passes through the prostate gland, enters the urethra and exits the body via the urinary meatus.
WAn erection is a physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, vascular, and endocrine factors, and is often associated with sexual arousal or sexual attraction, although erections can also be spontaneous. The shape, angle, and direction of an erection varies considerably in humans.
WGranulosa cell tumours are tumours that arise from granulosa cells. They are estrogen secreting tumors and present as large, complex, ovarian masses. These tumours are part of the sex cord-gonadal stromal tumour or non-epithelial group of tumours. Although granulosa cells normally occur only in the ovary, granulosa cell tumours occur in both ovaries and testicles. These tumours should be considered malignant and treated in the same way as other malignant tumours of ovary. The ovarian disease has two forms, juvenile and adult, both characterized by indolent growth, and therefore has high recovery rates. The staging system for these tumours is the same as for epithelial tumours and most present as stage I. The peak age at which they occur is 50–55 years, but they may occur at any age.
WGynecomastia is an endocrine system disorder in which a noncancerous increase in the size of male breast tissue occurs. Psychological distress or dysphoria may occur.
WHirsuties coronae glandis are small protuberances that may form on the ridge of the glans of the human penis. They are a form of acral angiofibromas. They are a normal anatomical variation in humans and are sometimes described as vestigial remnants of penile spines, sensitive features found in the same location in other primates. In species in which penile spines are expressed, as well as in humans who have them, the spines are thought to contribute to sexual pleasure and quicker orgasms. It has been theorized that pearly penile papules stimulate the female vagina during sexual intercourse. In addition, pearly penile papules secrete oil that moistens the glans of the penis.
WHuman penises vary in size on a number of measures, including length and circumference when flaccid and erect. Besides the natural variability of human penises in general, there are factors that lead to minor variations in a particular male, such as the level of arousal, time of day, room temperature, and frequency of sexual activity. Compared to other primates, including large examples such as the gorilla, the human penis is thickest, both in absolute terms and relative to the rest of the body.
WThe Icelandic Phallological Museum, located in Reykjavík, Iceland, houses the world's largest display of penises and penile parts. As of early 2020 the museum moved to a new location in Hafnartorg, three times the size of the previous one, and the collection holds well over 300 penises from more than 100 species of mammal. Also the museum holds 22 penises from creatures and peoples of Icelandic folklore.
WMale accessory gland infection (MAGI) is a condition with signs of inflammation involving one or more sites in the male genital tract. Diagnosis is made according to parameters defined by the World Health Organization, and it is particularly made in relation to infectious or inflammatory causes of male infertility.
WThe male infertility crisis is a name given to an observed increase in male infertility in recent decades. The earliest indications of this decrease first emerged in the 1970s. From this period there has been a steady decline of 1.4% in sperm counts. The matter is particularly relevant in the west in New Zealand, Australia, Europe & North America. A reduction in other parts of the world has yet to be observed.
WMale pregnancy is the incubation of one or more embryos or fetuses by male members of some species. Most species that reproduce by sexual reproduction are heterogamous—females producing larger gametes (ova) and males producing smaller gametes (sperm). In nearly all animal species, offspring are carried by the female until birth, but in fish of the family Syngnathidae, males perform this function.
WManliness is a book by Harvey C. Mansfield first published by Yale University Press in 2006. Mansfield is a professor of government at Harvard University. In this book, he defines manliness as "confidence in a situation of risk" and suggests this quality is currently undervalued in Western society.
WA teratoma is a tumor made up of several different types of tissue, such as hair, muscle, teeth, or bone. Teratoma typically form in the ovary, testicle, or coccyx.
WMen's health refers to a state of complete physical, mental, and social well-being, as experienced by men, and not merely the absence of disease or infirmity. Differences in men's health compared to women's can be attributed to biological factors, behavioural factors and social factors. These often relate to structures such as male genitalia or to conditions caused by hormones specific to, or most notable in, males. Some conditions that affect both men and women, such as cancer, and injury, also manifest differently in men. Men's health issues also include medical situations in which men face problems not directly related to their biology, such as gender-differentiated access to medical treatment and other socioeconomic factors. Some diseases that affect both genders are statistically more common in men. Outside Sub-Saharan Africa, men are at greater risk of HIV/AIDS – a phenomenon associated with unsafe sexual activity that is often nonconsensual.
WMen's Health Network (MHN) is a non-profit educational organization of health care professionals and interested individuals that focuses on improving male health and wellness. MHN has since been classified as a tax-exempt entity under Section 501(c)(3) of the U.S. Internal Revenue Service code.
WA penile implant is an implanted device intended for the treatment of erectile dysfunction, Peyronie's disease, ischemic priapism, deformity and traumatic injury of the penis, and for phalloplasty in men or phalloplasty and metoidioplasty in female-to-male gender reassignment surgery. Although there are many distinct types of implants, most fall into one of two categories: malleable and inflatable.
WProstate-specific antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KLK3), is a glycoprotein enzyme encoded in humans by the KLK3 gene. PSA is a member of the kallikrein-related peptidase family and is secreted by the epithelial cells of the prostate gland.
WReproductive medicine is a branch of medicine concerning the male and female reproductive systems. It encompasses a variety of reproductive conditions, their prevention and assessment, as well as their subsequent treatment and prognosis.
WSchiller–Duval body is a cellular structure seen by microscope in endodermal sinus tumors which are the most common testicular cancer in children. Schiller-Duval bodies are present in approximately 50% of these tumors, and if found are pathognomonic. They are named for Mathias-Marie Duval and Walter Schiller who described them in the late nineteenth century.
WSexual health clinics specialize in the prevention and treatment of sexually transmitted infections.
WThe spermatid is the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each spermatid contains only half of the genetic material present in the original primary spermatocyte.
WA varicocele is an abnormal enlargement of the pampiniform venous plexus in the scrotum. This plexus of veins drains blood from the testicles back to the heart. The vessels originate in the abdomen and course down through the inguinal canal as part of the spermatic cord on their way to the testis. Varicoceles occur in around 15% to 20% of all men. The incidence of varicocele increase with age.
WVas-occlusive contraception is a form of male contraception that blocks sperm transport in the vas deferens, the tubes that carry sperm from the epididymis to the ejaculatory ducts. Various vas-occlusive contraceptive methods have been researched for human-use, with interest in both reversible and irreversible methods, with the purpose of finding a suitable alternative to vasectomy and possible hormonal contraceptive treatments that are currently being researched. Potential methods include clips, plugs, valves, polymers, hydrogels, and other devices.
WThe Y chromosome is one of two sex chromosomes (allosomes) in mammals, including humans, and many other animals. The other is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or absence of Y that typically determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which triggers male development. The DNA in the human Y chromosome is composed of about 59 million base pairs. The Y chromosome is passed only from father to son. With a 30% difference between humans and chimpanzees, the Y chromosome is one of the fastest-evolving parts of the human genome. The human Y chromosome carries an estimated 100-200 genes, with between 45 and 73 of these protein-coding. All single-copy Y-linked genes are hemizygous except in cases of aneuploidy such as XYY syndrome or XXYY syndrome.