THE REPRODUCTIVE SYSTEM IN HUMANS AND RELATED DISEASES
VIETNAM NATIONAL UNIVERSITY OF AGRICULTURE FACULTY OF BIOTECHNOLOGY FINAL EXAMINATION SHE02002 – ANIMAL AND HUMAN BIOLOGY TOPIC: “THE REPRODUCTIVE SYSTEM IN HUMANS AND RELATED DISEASES” Student name Student code Class Faculty : Dao Trung Nghia : 637439 : K63CNSHE : Biotechnology Hanoi – 02/03/2021 CONTENTS I General information about the reproductive system in humans 1 The biological significance of reproductive system and development of the reproductive organs in humans .1 Male sexual physiology 2.1 Male reproductive system 2.2 Puberty in male, jaculation and rection 11 Female sexual physiology 14 3.1 Female reproductive syste 14 3.2 Puberty in the female, the reproductive cycle and menopause 23 II The diseases related to the reproductive system in humans 27 Chlamydia .27 1.1 The symptoms of Chlamydia’s disease 27 1.2 The causes of Chlamydia’s disease 27 1.3 Diagnosis of Chlamydia’s disease 28 1.4 Treatment and prevention of Chlamydia’s disease .29 Gonorrhoea 31 2.1 The symptoms of Gonorrhoea’s disease 31 2.2 The causes of Gonorrhoea’s disease .32 2.3 Diagnosis of Gonorrhoea’s disease 33 2.4 Treatment and prevention of Gonorrhoea’s disease .36 Syphilis 37 3.1 The symptoms of Syphilis’s disease 37 3.2 The causes of Syphilis’s disease .40 3.3 Diagnosis of Syphilis’s disease 41 3.4 Treatment and prevention of Syphilis’s disease 43 III References 45 I General information about the reproductive system in humans The biological significance of reproductive system and development of the reproductive organs in humans 1.1 The biological significance of the reproductive system in humans Reproduction is an important process for every living organisms because living organisms need to multiply to form new life, this process occurs within the reproductive organs During this process, a new generation comes into existence; therefore this process is not only essential for life, but it’s essential for the continued existence of species on earth The reproductive system comprises various body organs that help in procreation The system consists of sex organs that work together for reproduction Because of the vital role, many people acknowledge the fact the reproductive systems are the most important organs within the entire body For instance, the male reproductive system contains important organs located within the pelvic region with the main purpose of generating sperms needed during the fertilization process The reproductive system is an important set of organs because it facilitates the reproduction process since it contains fluids like hormone and pheromones that are important accessories for reproduction Unlike other body systems, the reproductive system is different depending on sex, both the male, female systems have unique composition with different fuctions, and this difference allows for a combination of the genetic material of two individuals to produce a unique offspring For the male organs, the three different sections facilitate reproduction, the firsr one being sperm production and for storage, which is the testes housed in the scrotum The testes contain immature sperm that moves to the epididymis, before the sperms is released On the other hand, the female reproductive system comprises of diffferent organs found inside and outside the body specifically around the pelvic area Like the male organ, the female reproductive system is also divided into three main sections, starting from the vagina that connects to the vulva and the vaginal opening that also connects to the uterus The uterus is the main part of the female reproductive system because it holds the fetus and contains ovaries that produce the eggs to be fertilized The vagina is also connected to the cervix and the Fallopian tubes, which is also connected to the ovaries Eggs from the ovaries are released and pass through the fallopian tube, which is connected to the ovaries If the egg is fertilized the egg is eliminated through menstruation Fertilization happens when the sperm enters the Fallopian tube Human fertilization takes place after internal fertilization has taken place Fertilization happens when the eggs from the female and the male meets during sexual intercourse When the sperms are released into the vigina, it moves through the vagina to the cervix and enter into the uterus ready for fertilization with the ovum When the fertilization is successful, the gestation process starts It takes approximately nine months as the gestation ends with labor that produces a baby The reproductive system can also be affected by certain diseases that can affect its fuctions Cancer is the most common disease that affects the system cancer In females, cancer attacks the uterus, the ovaries, and the cervix Men can also be affected by testicular, prostate and penile cancer that affects the different parts of their reproductive system If these diseases are not treated in time, the reproductive system might not function as expected because the disease might damage some of the important organs within the system Therefore, the reproductive system is one of the most important organ in the body because without then, there will be no living organisms Figure Organs and structures of the male and female reproductive systems 1.2 Development of the reproductive organs The sex of a child is determined at the time of fertilization of the ovum by the spermatozoon The differences between a male and a female are genetically determined by the chromosomes that each possesses in the nuclei of the cells Once the genetic sex has been determined, there normally follows a succession of changes that will result, finally, in the development of an adult male or female There is, however, no external indication of the sex of an embryo during the first eight weeks of its life within the uterus This is a neutral or indifferent stage during which the sex of an embryo can be ascertained only by examination of the chromosomes in its cells The next phase, one of differentiation, begins first in gonads that are to become testes and a week or so later in those destined to be ovaries Embryos of the two sexes are initially alike in possessing similar duct systems linking the undifferentiated gonads with the exterior and in having similar external genitalia, represented by three simple protuberances The embryos each have four ducts, the subsequent fate of which is of great significance in the eventual anatomical differences between men and women Two ducts closely related to the developing urinary system are called mesonephric, or wolffian, ducts In males each mesonephric duct becomes differentiated into four related structures: a duct of the epididymis, a ductus deferens, an ejaculatory duct, and a seminal vesicle In females the mesonephric ducts are largely suppressed The other two ducts, called the paramesonephric or müllerian ducts, persist, in females, to develop into the fallopian tubes, the uterus, and part of the vagina; in males they are largely suppressed Differentiation also occurs in the primitive external genitalia, which in males become the penis and scrotum and in females the vulva (the clitoris, labia, and vestibule of the vagina) Figure Differentiation of external genitalia in the human embryo and fetus At birth the organs appropriate to each sex have developed and are in their adult positions but are not functioning Various abnormalities can occur during development of sex organs in embryos, leading to hermaphroditism, pseudohermaphroditism, and other chromosomally induced conditions During childhood until puberty there is steady growth in all reproductive organs and a gradual development of activity Puberty marks the onset of increased activity in the sex glands and the steady development of secondary sexual characteristics In males at puberty the testes enlarge and become active, the external genitalia enlarge, and the capacity to ejaculate develops Marked changes in height and weight occur as hormonal secretion from the testes increases The larynx, or voice box, enlarges, with resultant deepening of the voice Certain features in the skeleton, as seen in the pelvic bones and skull, become accentuated The hair in the armpits and the pubic hair becomes abundant and thicker Facial hair develops, as well as hair on the chest, abdomen, and limbs Hair at the temples recedes Skin glands become more active, especially apocrine glands (a type of sweat gland that is found in the armpits and groin and around the anus) In females at puberty, the external genitalia enlarge and the uterus commences its periodic activity with menstruation The breasts develop, and there is a deposition of body fat in accordance with the usual contours of the mature female Growth of axillary (armpit) and pubic hair is more abundant, and the hair becomes thicker Male sexual physiology 2.1 Male reproductive system Figure The male reproductive organs and their associated structures The functions of the male reproductive organs are: - Production, maturation and storage of spermatozoa - Delivery of spermatozoa in semen into the female reproductive tract The urethra is also the passageway for urine excretion 2.1.1 Scrotum - Structure: The scrotum is a pouch of pigmented skin, fibrous and connective tissue and smooth muscle It is divided into two compartments, each of which contains one testis, one epididymis and the testicular end of spermatic cord It lies below the symphysis pubis, in front of the upper parts of the thighs and behind the penis - Fuction: The scrotum protects your testes, as well as providing a sort of climate control system For normal sperm development, the testes must be at a temperature slightly cooler than the body temperature Special muscles in the wall of the scrotum allow it to contract (tighten) and relax, moving the testicles closer to the body for warmth and protection or farther away from the body to cool the temperature 2.1.2 Testes Figure The testis A Section of the testis and its coverings B Longitudinal section of a testis and deferent duct They are about 4.5 cm long, 2.5 cm wide and cm thick and are suspended in the scrotum by the spermatic cords They are surrounded by three layers of tissue - Tunica vaginalis This is a double membrane, forming the outer covering of the testes, and is a downgrowth of the abdominal and pelvic peritoneum During early fetal life, the testes develop in the lumbar region of the abdominal cavity just below the kidneys They then descend into the scrotum, taking with them coverings of peritoneum, blood and lymph vessels, nerves and the deferent duct The peritoneum eventually surrounds the testes in the scrotum, and becomes detached from the abominal peritoneum Descent of the testes into the scrotum should be complete by the 8th month of fetal life - Tunaca albuginea This is a fibrous covering beneath the tunica vaginalis Ingrowths from septa, dividing the glandular structure of the testes intio lobules - Tunica vasculosa This consists of a network of capillaries supported by delicate connective tissue 2.1.3 Sperm Figure A spermatozoon - Structure: In each testis are 200–300 lobules, and within each lobule are 1–4 convoluted loops of germinal epithelial cells, called seminiferous tubules Between the tubules are groups of interstitial cells (of Leydig) that secrete the hormone testosterone after puberty At the upper pole of the testis the tubules combine to form a single tubule This tubule, about m in its full length, is repeatedly folded and tightly packed into a mass called the epididymis It leaves the scrotum as the deferent duct (vas deferens) in the spermatic cord Blood and lymph vessels pass to the testes in the spermatic cords - Function: Spermatozoa (sperm) are produced in the seminiferous tubules of the testes, and mature as they pass through the long and convoluted epididymis, where they are stored FSH from the anterior pituitary stimulates sperm production A mature sperm has a head, a body, and a long whip-like tail used for motility The head is almost completely filled by the nucleus, containing its DNA It also contains the enzymes required to penetrate the outer layers of the ovum to reach, and fuse with, its nucleus The body of the sperm is packed with mitochondria, to fuel the propelling action of the tail that powers the sperm along the female reproductive tract Successful spermatogenesis takes place at a temperature about 3°C below normal body temperature The testes are cooled by their position outside the abdominal cavity, and the thin outer covering of the scrotum has very little insulating fat Unlike females, who produce no new gametes after birth, sperm production in males begins at puberty and continues throughout life, often into old age, under the influence of testosterone 2.1.4 Spermatic cords - Structure: The spermatic cords suspend the testes in the scrotum Each cord contains a testicular artery, testicular veins, lymphatics, a deferent duct and testicular nerves, which come together to form the cord from their various origins in the abdomen The cord, which is covered in a sheath of smooth muscle and connective and fibrous tissues, extends through the inguinal canal and is attached to the testis on the posterior wall Figure Section of the prostate gland and associated reproductive structures on one side - Function: * Blood supply, lymph drainage and nerve supply Arterial supply The testicular artery branches from the abdominal aorta, just below the renal arteries Venous drainage The testicular vein passes into the abdominal cavity The left vein opens into the left renal vein and the right into the inferior vena cava Lymph drainage This is through lymph nodes around the aorta Nerve supply This is provided by branches from the 10th and 11th thoracic nerves * The deferent duct This is some 45 cm long It passes upwards from the testis through the inguinal canal and ascends medially towards the posterior wall of the bladder where it is joined by the duct from the seminal vesicle to form the ejaculatory duct ( Fig ) 2.1.4 Seminal vesicles - Structure: The seminal vesicles are two small fibromuscular pouches, 5cm long, lined with columnar epithelium and lying on the posterior aspect of the bladder ( Fig 6) At its lower end each seminal vesicle opens into a short duct, which joins with the corresponding deferent duct to form an ejaculatory duct - Function: The seminal vesicles contract and expel their stored contents, seminal fluid, during ejaculation Seminal fluid, which forms 60% of the volume of semen, is alkaline to protect the sperm in the acidic environment of the vagina, and contains fructose to fuel the sperm during their journey through the female reproductive tract 2.1.5 Ejaculatory ducts The ejaculatory ducts are two tubes about cm long, each formed by the union of the duct from a seminal vesicle and a deferent duct They pass through the prostate gland and join the prostatic urethra, carrying seminal fluid and spermatozoa to the urethra ( Fig 6) The walls of the ejaculatory ducts are composed of the same layers of tissue as the seminal vesicles 2.1.6 Prostate gland - Structure: The prostate gland ( Fig ) lies in the pelvic cavity in front of the rectum and behind the symphysis pubis, completely surrounding the urethra as it emerges from the bladder It has an outer fibrous covering, enclosing glandular tissue wrapped in smooth muscle The gland weighs about g in youth, but progressively enlarges (hypertrophies) with age and is likely to weigh about 40 g by the age of 50 - Function: The prostate gland secretes a thin, milky fluid that makes up about 30% of the volume of semen, and gives it its milky appearance It contains a clotting enzyme, which thickens the semen in the vagina, increasing the likelihood of semen being retained close to the cervix Secondary prevention by universal screening is likely to play critical role in the prevention of PID and long-term sequelae Chlamydial infections fill the general prerequisites for disease prevention by screening, since they are highly prevalent, are associated with significant morbidity, can be diagnosed, and are treatable Secondary prevention means early detection of asymptomatic disease by screening in order to prevent lower genital tract infection from becoming upper genital tract infection Recent technological advances should further enhance efforts to prevent chlamydial infection These include single-dose therapy using azithromycin, utilization of NAAT, and the use of FVU specimens for the diagnosis However, it remains to be seen whether such intervention will also have a significant effect on the incidence of tubal factor infertility The Swedish experience strongly suggests that screening efforts to reduce C.trachomatis infection and PID result in a decline of ectopic pregnancies Gonorrhoea 2.1 The symptoms of Gonorrhoea’s disease Figure 18.The symptoms of Gonorrhoea’s disease 31 This is caused by the bacterium Neisseria gonorrhoea, which infects the mucosa of the reproductive and urinary tracts In the male, suppurative urethritis occurs and the infection may spread to the prostate gland, epididymis and testes In the female, the infection may spread from vulvar glands, vagina and cervix to the body of the uterus, uterine tubes, ovaries and peritoneum Healing by fibrosis in the female may obstruct the uterine tubes, leading to infertility In the male it may cause urethral stricture Nonvenereal transmission of gonorrhoea may cause neonatal ophthalmia in babies born to infected mothers The eyes become infected as the baby passes through the birth canal 2.2 The causes of Gonorrhoea’s disease Figure 19 The causes of Gonorrhoea's disease 32 Gonorrhoea’s disease caused by the bacterium Neisseria gonorrhoeae It is a fastidious organism that is sensitive to many environmental factors such as oxygen, nonphysiological temperatures, desiccation and the presence of toxic substances (such as many fatty acids), among others; thus, the bacterium does not survive for long outside the human host, and is difficult to culture Many strains have incomplete biosynthetic capabilities for amino acids, presumably because amino acids and other important nutrients are readily obtained from the human host Iron (which is essential for bacterial growth) is acquired from the host by binding iron-containing host proteins such as transferrin, lactoferrin and haemoglobin at the bacterial surface and stripping these molecules of iron that is then delivered to the bacterial cytoplasm Owing to the broad range of oxygen levels within different niches of the male and female urogenital tracts, it is possible that N gonorrhoea encounters aerobic, microaerobic, and anaerobic conditions within the host, and the bacteria are able to grow in all these conditions In addition, N gonorrhoea can acquire additional DNA via horizontal genetic transfer (HGT), the noninherited external acquisition of new genetic material from another bacterium HGT occurs mainly by type IV pilus-mediated DNA transformation (uptake of DNA from the environment and subsequent incorporation into the genome) N gonorrhoea is naturally competent for transformation during its entire life cycle 2.3 Diagnosis of Gonorrhoea’s disease The incubation period for urogenital gonorrhoea ranges from ~2 days to days The clinical manifestations of gonorrhoea are variable and differ markedly in men and women At least 90% of men with gonococcal urethritis are symptomatic, presenting with obvious urethral discharge and dysuria, a fact that permits the application of syndromic diagnosis (based on a set of symptoms and signs that are characteristic of a clinical manifestation) in many settings as both a time-saving and cost-saving measure For men with symptomatic urethritis, Gram stain may be used to support symptom evaluation By contrast, laboratory-based diagnostic tests have a more important role for gonococcal detection in asymptomatic men, women and in patients of all genders for extragenital (rectal and pharyngeal) infections, which are mostly asymptomatic or present with nonspecific symptoms Although approximately 40% of women with gonococcal cervicitis may report abnormal vaginal discharge, this symptom is unreliable for syndromic diagnosis of gonorrhoea, as many other equally or more common genitourinary infections in women (for example, bacterial vaginosis, trichomoniasis and vaginal candidiasis) may cause the same symptoms Microbiological diagnosis of gonorrhoea can be challenging, as many regions not have a laboratorybased diagnostic capability and rely on syndromic management algorithms to guide empirical antimicrobial treatments Microbiological diagnosis is performed by the detection of Gram-negative diplococci in stained smears using 33 microscopy, culture of N gonorrhoeae and/or nucleic acid amplification tests (NAATs) detecting N gonorrhoeae DNA or RNA Traditional diagnostic methods Microscopy In resource-limited settings, light microscopy of Gram-stained samples is often the only method available to diagnose infection with N gonorrhoeae presumptively.The sensitivity and specificity of the Gram stain, which tests for the presence of characteristic Gram-negative diplococci within PMNLs, can vary substantially between studies and depends upon the specimen; the highest sensitivity and specificity were reported with urethral swab samples from symptomatic males (89% to > 98% and > 95%, respectively), whereas the sensitivity was as low as 40– 50% in urethral specimens from asymptomatic males, and in endocervical or urethral specimens from women This difference can probably be explained by a reduced bacterial load, particularly in these urethral samples, and by the presence of many other bacterial species in the endocervical samples Gram stain is not suitable for the diagnosis of N gonorrhoeae from pharyngeal specimens (because other Neisseria species with similar morphology are prevalent in the oral and nasopharyngeal cavity) or rectal specimens (which have a sensitivity ≤ 40%) A methylene blue staining method is an alternative to the Gram stain, and similar high sensitivity and specificity were reported for diagnosing gonococcal urethritis in men Culture Prior to the introduction of NAATs, culture of the organism was the gold standard and this remains the only diagnostic method available in some settings as it is a low-cost method Culture also remains recommended for test-of-cure for treatment failure, in cases of sexual abuse and to evaluate PID Furthermore, complete AMR testing can only be accomplished if N gonorrhoeae is cultured Culture performance is dependent upon factors such as anatomical site of the cultured sample, method of specimen collection, media and conditions used to transport the sample to the diagnostic centre, nonselective and/or selective culture media, conditions of incubation and species confirmatory tests Cultures obtained too soon after exposure (