Y khoa, y dược - Chapter 9: The reproductive system

Chapter 9 The Reproductive SystemIntroductionThe reproductive system is one of the only systems in the body that is dimorphic, meaning it is both functionally and structurally different in males and females.The reproductive system is particularly important as it enables the human species to survive.Both systems are able to function as a response to male and female sex hormones, which are secreted by the gonads or sex glands.Function of the Reproductive System The reproductive system enables the human species to continue and genetic material to be passed from parent cells to daughter cells. Various organs of the reproductive system are formed during the embryonic stage, however, normal function of the reproductive system begins at puberty The organs can be grouped by their function, the testes and ovaries are known as gonads and their function is to produce gametes and secrete hormones. The testes produce sperm cells and the ovaries produce ova. The male reproductive system is made up of testes, ducts, accessory sex glands and supporting structures, which includes the penis. Scenario Rob Short, a 19-year-old Caucasian male, walks into the emergency department after suffering a sudden onset of pain in his left testicle four hours ago, he states that the testicle is swollen although it is not visualised at triage. He looks pale and is sweating.His vital signs are as follows:Respiratory rate 18, Pulse 98, Blood Pressure 110/72, Temp 36.9Pain score on assessment is 3 out of 4He has no relevant medical history and no known allergies to medicine Assessment and Analysis of Patient Presentation Mr Short has presented with clinical signs and symptoms of testicular pain, the most serious type of illness associated with the sudden onset of pain in the testicles would be torsion of the testicle. His vital signs show an increased heart and respiratory rate, he is sweating, a sympathetic response to pain. He also verbalises that he has a pain score of 3 out of 4 that can be categorised as severe pain. Mr Short falls within a high-risk category for testicular torsion due to his age. Testicular torsion is more common in teenagers but can occur at any age. The acute onset of his pain is also another indicator of testicular torsion, a more gradual onset could be a number of other illness. Pathophysiology A testicular torsion is the twisting of a testicle, the spermatic cord contains the vas deferens, autonomic nerve, testicular veins and artery. When the cord becomes twisted it occludes the blood supply to the testicle, if the testicle is not surgically untwisted within 6 hours it will infarct and the testicle will perish. The fertility or sexual function of these men should not be affected as the remaining testicle can still produce testosterone and sperm. If the blood supply is restored during surgery normal sexual function and fertility are restored. Psychosocial Aspects Consider Mr Short’s fears and anxiety about the operation Ensure he understands the procedure and its possible outcomes. Alleviating a patients fear about surgery or treatment they are to experience has been shown to aid recovery times (Janis 1958). It is important that patients fully understand the procedure they are having. Mr Short was worried about the long-term effects on his fertility and sexual health; the surgeon must alleviate these fears. During discussion it is imperative that the surgeon uses language that can be easily understood by a patient, it may also be important to emphasise the low risk of reduced fertility and sexual dysfunction. The Penis The penis is a cylindrical structure that can also be broken into three parts; the bodythe root the glans penis The body has three types of tissue that are cylindrical in shape.The root of the penis is the attached part and contains the bulb of the penis. The glans penis is acorn shaped and is located at the distal end of the penis. The external urethral meatus is the opening for urine and semen to pass through; this is located at the glans penis. Male Hormones & Spermatogenesis Testosterone can be found in the testes and is the main male sex hormone (androgen). There are several functions of testosterone;Prior to birth it stimulates the foetus to develop a male reproductive system and ensures the decent of the testes from the abdominal wall to the scrotum. During this stage of development the DHT stimulates the growth of external genitalia such as the penis. At puberty testosterone and DHT work to ensure the transition from child to sexually mature man, this includes growth of genitals, increased muscle mass and change in skeletal structure. Finally it aids spermatogenesis (production of sperm) making the male fertile and is responsible for libido in both men and women. The Gonadotrophic Hormones The anterior pituitary gland secretes Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) during puberty. LH stimulates the Leydig cells to release testosterone. The hypothalamus secrets Gonadotrophin releasing hormone (GnRH); this hormone is essential as it regulates the release of FSH and LH. If the levels are too high it inhibits the release of GnRH, which in turn reduces the release of LH, this then inhibits the release of testosterone. This is known as a negative feedback system. Finally inhibin is a hormone that regulates spermatogenesis. The hormone is located in the sertoli cells and is released when spermatogenesis has reached an optimum level for reproduction. This in turn inhibits the secretion of FSH, which then slows the process of spermatogenesis down.Function of Female Hormones Oestrogens: promote development of reproductive structures, in particular the changes in the endometrium with each cycle. Development of the secondary sex characteristics, including breasts, voice pitch, hair pattern and the depositing of fat at the hips and abdomen. Progesterone: works with oestrogen to prepare the endometrium for fertilised ovum and also prepares the mammary glands for milk secretion.Inhibin: inhibits secretion of GnRH and FSH during the uterine cycle.Relaxin: high quantities produced in the last trimester of pregnancy relaxes the pubic symphysis, dilates the cervix during delivery. The Female Reproductive System The ovaries (female gonads) lie in the pelvic cavity and are ovoid in shape. The function of the ovaries is to house and then expel ova (egg). There are two ovaries that are located either side of the uterus and are connected by the fallopian tubes. The cortex contains the ovarian follicles which has an inner layer called the medulla. The final part of the ovary is the corpus luteum, this is a mature ovarian follicle that has ruptured releasing a secondary oocyte, and this process is known as ovulation and occurs monthly once puberty has begun. Fallopian Tubes & The Uterus There are two fallopian tubes, which connect the ovaries with the uterus. They propel the ova from the ovaries to the uterus. The uterus is a pear shaped structure located on the superior surface of the bladder.The uterus has several functions; it is part of the pathway for the sperm to reach the fallopian tubes, it implants the fertilised ovum and enlarges to house the growing foetus. It is also the site of menstruation. The uterus is composed of three areas, the fundus, the body and the cervix. The fundus is a dome shaped structure that rises above the fallopian tubes. The body is the central area of the uterus, and the cervix is the narrow portion that descends into the vagina. The VaginaThe vagina measures approximately 10cms in length. The function of the vagina is to act as a passageway; for blood flow during the menstrual cycle, the foetus during childbirth, and to receive semen from the penis during penetrative intercourse. The vagina is made up of smooth muscle called muscularis, The lower end of the vagina is called the vaginal orifice where the mucous membrane called the hymen is located. Breasts/Mammary Glands Prior to puberty both male and female chests appear the same. At puberty the release of oestrogens and progesterone encourages breast tissue growth. The breasts are made up of adipose tissue, the amount of adipose tissue a woman has determines her breast size. The mammary glands are modified sweat glands that produce milk; each gland has 15 to 20 lobes. Scenario Maria Harman is a 35-year-old Caucasian lady. She is married with children. Maria attends her GP surgery with a pea size lump in her right breast. She noticed it in the shower, she examines her breasts regularly. It is not painful. PMH: Mild Asthma AssessmentMaria explained she noticed the lump yesterday, her friend has recently been diagnosed with breast cancer so she has been carrying out regular breast self examination (BSE) in order to detect any changes early. Through regular breast examination the patient or their partner will discover 80% of lumps. A history is taken including dates of her LMP as changes in the breast can be due to hormonal changes around the menstrual cycle. Also relevant medical and familial history was taken; Maria has no family history of breast cancer. The examination begins by looking for irregularities in the shape or colour of the breast and nipple and the lymph nodes under the armpit. This is because breast lumps and cancer can be located in the lymph nodes. The GP detects a lump in her right breast. The GP tried to allay Maria’s fears, by explaining the importance of definitive diagnosis; this would be achieved by an ultrasound and fine needle aspiration cytology (FNAC). Although the GP felt it was benign these tests would confirm the provisional diagnosis. Psychosocial Aspects Mrs Harman is very worried about breast cancer, as her friend has recently been diagnosed with it. Maria has been taught by her friend the importance of BSE, she also showed her the correct technique for examining the breasts. One way the health care professional can make sure the patient has comprehended the treatment or diagnosis is by asking them to explain what they have understood. Written information is also a key part in any care given to a patient, as they are able to take the literature away from the clinical setting and study it in a less stressful environment. Treatment Mrs Harman waited two weeks for her appointment. The clinic advised her to bring a friend or partner for support. On arrival she was greeted by a nurse who explained the procedures to her in detail, a written information book was provided before her consultation. It is important to give the patients’ time to understand clinical procedures, this will enable them to understand what is happening and provides the opportunity for questions. Maria appeared to have understood the procedure but was anxious about the findings, it is imperative that anxieties are recognised and addressed by the nurse and time is given to the patient. The ConsultationThe consultant began by taking a brief history from Maria, and will undertake the procedure themselves, a result available that afternoon. Maria’s breasts are inspected; the consultant looks for any changes in shape, puckering of the skin, colour changes, rashes, inversion or discharge affecting the nipples. The breasts have no obvious deformities. The ultrasound confirmed a small 1.5cm lump. The consultant used a local anaesthetic took a small amount of aspirate for cytology. The consultant explained that the lump appeared to be a fibroadenoma, which is a benign lump but the cytology would confirm it. Fibroadenomas’ are common in young women and are hard moveable lumps approximately 1-3cm in diameter. It is believed they are caused by an increased sensitivity to oestrogen. Mrs Harman is told to take simple analgesia later that day as the breast may become tender following the procedure. The results confirm that Maria had a benign fibroadenoma, the consultant explains that if the lump grows she it could be removed if it becomes troublesome. Maria is advised to continue her self examination. Female Reproductive Cycle - Exercise Once puberty has occurred, women experience a monthly cycle, the length of which varies but is usually between 21-35 days. Hormones that are released by the hypothalamus, pituitary gland and ovaries control the cycle. The cycle can be broken down into four phases.Menstrual phasePreovulatory phaseOvulation Postovulatory phaseResearch further information on each stage and add the information to your portfolio Pregnancy Women are fertile during the years that they menstruate and can become pregnant if sexually active, during this time. Once the ovum has been fertilised by sperm the young embryo begins to develop. Pregnancy lasts forty weeks from the date of the last menstrual period (LMP) to birth. The pregnancy is divided into three trimesters, which are approximately 12 weeks each. During the early stages the embryo is called a zygote. At day 6 or 7 the embryo implants itself in the uterus and attaches to ensure that the maternal blood supply feeds oxygen and nutrients to the growing embryo.Pregnancy 2During the implantation stage the embryo is at risk of implanting in various sites such as the uterine tube, this is known as an ectopic pregnancy. Once the embryo is implanted the cells release a hormone called human chorionic gonadotrophin (HCG)The associated sharp increase in female hormone levels can lead to morning sicknessAt the end of the first trimester the embryo is known as a foetus. Pregnancy 3The second trimester begins in the 13th week. During this trimester the foetus has all the major organs and therefore begins to develop purposeful movement. The mother can detect foetal movements at 16 weeks onwards. At approximately 20 weeks most mothers will have an anomaly scan which detects any abnormalities in any of the major organs..The third trimester begins at week 27 and lasts until labour begins. Delivery after 37 weeks gestation is deemed normal, although some women will give birth in the 42nd week. Oxytocin helps the uterus expel the placenta after the baby has been born. Once the placenta has been expelled the breasts begin to produce small amounts of colostrums.Miscarriage One in five pregnancies ends in miscarriage.50-80% of women who have bleeding in the first trimester of pregnancy will continue to have a normal pregnancy.Many miscarriages occur within the first trimesterThere can be many reasons for a miscarriage to occur;Genetic abnormality that is incompatible with life. Infection such as German measles. Immunological problems, for example problems with blood vessels that supply the placenta.Hormonal imbalances Anatomical causes in the mother, such as a weak cervixConclusion The male and female reproductive systems have been discussed in depth. The development of the reproductive system and the hormones involved in the male and female systems have been identified, including the changes that occur in puberty and pregnancy. Clinical scenarios have highlighted main themes. It is important to update personal portfolios when new illnesses or diseases are seen in clinical placements.