NSS 323 Maternal and Child Health Nursing 1 PDF

NATIONAL OPEN UNIVERSITY OF NIGERIA SCHOOL OF SCIENCE AND TECHNOLOGY COURSE CODE: NSS 323 COURSE TITLE: MATERNAL AND CHILD HEALTH NURSING I 1 NSS 323 MATERNAL AND CHILD HEALTH NURSING I Course Developer Mrs. Lydia T. Dada S...

NATIONAL OPEN UNIVERSITY OF NIGERIA SCHOOL OF SCIENCE AND TECHNOLOGY COURSE CODE: NSS 323 COURSE TITLE: MATERNAL AND CHILD HEALTH NURSING I 1 NSS 323 MATERNAL AND CHILD HEALTH NURSING I Course Developer Mrs. Lydia T. Dada School of Midwifery University College Hospital Ibadan Programme Leader Prof. Afolabi Adebanjo School of Science and Technology National Open University of Nigeria, Lagos Course Coordinator Kayode S. Olubiyi School of Science and Technology National Open University of Nigeria, Lagos 2 NATIONAL OPEN UNIVERSITY OF NIGERIA National Open University of Nigeria Headquarters 14/16 Ahmadu Bello Way Victoria Island Lagos Abuja Annex 245 Samuel Adesujo Ademulegun Street Central Business District Opposite Arewa Suites Abuja E-mail: [email protected] URL: www.nou.edu.ng National Open University of Nigeria 2008 First Printed 2008 ISBN: All Rights Reserved Printed by…………………………………. For National Open University of Nigeria 3 TABLE OF CONTENTS PAGE Introduction……………………………………………… 1 What you will learn in this course…………………… 2 Course Aim………………………………………… 2 Course Objectives……………………………………….. 2-3 Working through this course……………………………. 2-3 Course Materials………………………………………… 3 Study Units……………………………………………… 3-4 Recommended Texts…………………………………….. 4 Assignment File…………………………………………. 4 Presentation schedule……………………………………. 4 Assessment………………………………………………. 5 Tutor Marked Assignments (TMAs)…………………….. 5-6 Final Examination and Grading………………………… 6 Course Marking Scheme………………………………… 7 Course Overview………………………………………… 7-8 How to get the most out of this course……………… 8 Tutors and Tutorials ………………………………… 9 4 Introduction NSS 323: Maternal and Child Health Nursing I is a three (3) unit course for the students in the Bachelor of Nursing Science programme. The course is broken into 4 modules with 17 study units. It will introduce the students to Maternal and Child Care by evidence based midwifery practice in the hospital and outside the hospital. The anatomy and physiology information is very easy to understand. The course will also encourage the learners to put in their best in presence of many challenges that are facing nurses and midwives in the course of their profession practice such as inadequacy of staff, facilities and motivation in the developing countries. At the end of the course, the learner is expected to demonstrate clear understanding of maternal and child care and develop specialized knowledge and skills for midwifery practice and issues challenging reproductive health services in the society. The learner will be able to explain her/his role, being the person alongside and supporting women at child birth. The learner will be knowledgeable in recognizing deviation from normal and act promptly to alleviate the suffering of women in pain or discomfort and be able to apply it in true-life situation. This course guide 5 provides what to expect in the course, and how to work through the course material as a distance learner who has to study on his/her own. Tutorial sessions are also linked up with the course to provide the needed support you required. What You Will Learn In This Course Today, Nigeria has a population of 140 million people. Despite the Federal Government’s efforts to reduce maternal mortality rate through safe motherhood programme the death rate related to child birth is still on the increase. The latest figure by the ministry of statistics estimated maternal mortality rate to be about 800 per 100,000 live births.This figure is alarming and it is a great challenge to health services especially maternal and child care. The significance of this course, Maternal and Child Care [MCH] is to help you see the germane role of maternal and child care as a means of providing health services to the populace. Course Aim This course is designed to provide adequate knowledge of maternal and child care to Nurses and Midwives. It is believed that at the end of the course students will be better equipped to improve their competence, confidence and job satisfaction. They will be able to render quality care to their patients, procurement of medical assistance and execution of emergency measures in the absence of 6 medical help. This you can achieve by independent judgment, providing appropriate care including family planning. Course Objectives To achieve the aims set out above, the course sets the overall objective. In addition, each unit has specific objectives stated at the beginning of a unit. Learners are advised to read them carefully before going through the unit. You will have to refer to them during the course of your study to monitor your progress. You are encouraged to always refer to the Unit objectives after completing a Unit. This is the way you can be certain that you have done what was required of you in the unit. The wider objectives of the course are set below. By meeting these objectives, you should have achieved the aims of the course as a whole. On successful completion of the course, you should be able to: Describe the structures and functions of the female and male reproductive Organs. Clarify sex determination of male and female traits. Describe the physical and psychological reproductive changes that take place during puberty and pregnancy as well as at menopause. 7  Give optimal care to woman during childbirth. Teach positive health practice. Appreciate the importance of good history taking during admission Identify common discomforts associated with childbirth. Describe the developmental tasks that indicate family adaptation to pregnancy. State the benefit of encouraging father’s participation in childbirth. Describe assessment and nursing intervention for women diagnosed with complications associated with childbirth. Discuss the key factors that might influence an individual’s preferences for various contraceptive methods. Identify the most common sexually transmitted diseases including modes of transmission, treatment and prevention. Working Through This Course To complete this course, you are required to study through the units, the recommended textbooks and other relevant materials. Each unit contains some self assessment exercises and tutor 8 marked assignments and at some point in this course, you are required to submit the tutor marked assignments. This will be followed by an end of term examination. Course Materials The following are the components of this course: 1. The Course Guide 2. Study Units 3. Textbooks 4. Assignment File 5. Presentation Schedule Study Units This course is made up 17 study units in 4 modules. These are: Module 1 Review of Reproductive and Urinary System Unit 1 Anatomy and Physiology of Female Reproductive System Unit 2 The Female Reproductive System Unit 3 The Male Reproductive System Unit 4 Foetal and Placenta Development and Foetal Circulation Unit 5 Urinary System Module 2 Physiology of Pregnancy Unit 6 Physiology of Pregnancy Unit 7 Prenatal Care 9 Unit 8 Labour Unit 9 Management of Labour Unit 10 Puerperium Module 3 Abnormal Conditions in Pregnancy and Labour Unit 11 Abnormal Conditions in Pregnancy and Labour Unit 12 Obstetrics conditions that complicate pregnancy Unit 13 Medical Conditions in Pregnancy Unit 14 Malpresentation/positions in Pregnancy Module 4 Obstetric Emergencies Unit 15 Obstetric Emergencies Unit 16 Abnormal Puerperium Unit 17 Obstetric Interventions Each unit contains self assessment exercise and tutor marked assignments of which the learners are required to attempt. Expectedly, it is believed that the exercise will help you to achieve the stated objective. Recommended Textbooks for This Course Cox, C.L. 1995. Health and Human Needs. In H. B. M. Heath (ed.) Potters and Perry’s Foundations in Nursing Theory and Practice. Italy: Mosby, an imprint of Times Mirror International 10 Ewles and Simnett (1985) Health Education and Patient Teaching in Watsons Medical Surgical Nursing and Related Physiology Pg. 23 Kozier, B., Erb, G., Berman, A.U. & Burke, K. (eds.) 2000. Health, Wellness and Illness. Fundamental of Nursing: Concepts Process and Practice (6th edition). New Jersey: Prentice Hall, Inc. Lucas A. O and Guiles H. M (1984) Preventive medicine for the Tropics, Kent, Hodder and Stoughton Ltd. Lucas and Guiles (1989) A short textbook of preventive Medicine for the Tropics, 2nd Edition, ELBS. Santhosh, M. (2000) Primary Health Nursing (PHN) Indria Gandhi National Open University, New Deli, Berny Art Press. Assignment File The assignment file will contain the Tutor Marked Assignment (TMA) which will constitute part of the continuous assessment (CA) of the course. There are 15 assignments in this course with each unit having an activity/exercise for you to do to facilitate your learning as an individual. 11 Presentation Schedule This presentation schedule in this course provides with important dates for completion of each unit and tutor marked assignment. Please try to meet the deadlines. Assessment There are two aspects to the assessment of the course. These are the Tutor marked assignment and written examination. In tackling the assignments, you are expected to apply information, knowledge and strategies gathered during the course. The assignments must be turned in to your tutor for formal assessment in accordance with the stated presentation schedules. The works you submit to your tutor for assessment will count for 40% of your total course work. At the end of the course you will need to sit for a final written examination of three hour’s duration. This examination will also count for 60% of your total course mark. Tutor Marked Assignment (TMA) There are Tutor-marked assignments in each of the units. You are expected to study them while going through this course. However, you will be given the four (4) to be submitted for assessment from the Study Centre. You are advised in your own interest to submit the assignments at the stipulated time. You will be able to 12 complete the assignments from the information and materials contained in your reading and study units. There is other self activity contained in the instructional material to facilitate your studies. Try to attempt it all. Feel free to consult any of the references to provide you with broader view and a deeper understanding of the course. Final Examination and Grading The final examination of NSS 323 will be of 3 hours duration and have a value of 60% of the total course grade. The examination will consist of questions which have bearings with the attempted self assessment exercises and tutor marked assignments that you have previously encountered. Furthermore, all areas of the course will be evaluated. Make sure you give enough time to revise the entire course. Course Marking Scheme The following table includes the course marking scheme Table 1 Assessment Marks Assignment 4 4 assignments for the best Total = 10% x 4 = 40% Final examination 60% of overall course marks 13 Total 100% of course marks Course Overview This table indicates the units, the number of weeks required to complete the assignments. Unit Title of Work Week Assessment Activity Course Guide Week 1 Module 1 Review of Reproductive and Urinary System Unit 1 Anatomy and Physiology Week 2 of Female Reproductive System Unit 2 The Female Reproductive System Week 3 Unit 3 The Male Reproductive System Week 3 Unit 4 Foetal and Placenta Development with Foetal Circulation Week 4 Unit 5 Urinary System Week 4 14 Module 2 Physiology of Pregnancy Unit 6 Physiology of Pregnancy Week 5 Unit 7 Prenatal Care Week 6 Unit 8 Labour Week 7 Unit 9 Management of Labour Week 7 Unit 10 Puerperium Week 8 Module 3 Abnormal Conditions in Pregnancy and Labour Unit 11 Abnormal Conditions in Week 9 Pregnancy and Labour Unit 12 Obstetrics conditions that Week complicate pregnancy 10 Unit 13 Medical Conditions in Week Pregnancy 10 Unit 14 Malpresentations/positions Week in Pregnancy 11 Module 4 Obstetric Emergencies Unit 15 Obstetric Emergencies Week 12 Unit 16 Abnormal Puerperium Week 12 Unit 17 Obstetric Interventions Week 15  13 How To Get The Most Out Of The Course In distance learning, the study units replace the university lecture. This is one of the greatest advantages of distance learning. You can read and work through specially designed study materials at your own pace and at time and place that suit you best. Think of it as reading the lecture notes instead of listening to a lecturer. In the same way that a lecturer might set you some reading task, the study units tell you when to read your other material. Just as a lecturer might give you an in-class exercise, your study units provide exercise for you to do at appropriate points. The following are practical strategies for working through the course: Read the course guide thoroughly. Organize a study schedule. Stick to your own created study schedule. Read the introduction and objectives very well. Assemble your study materials. Work through the unit. 16  Keep in mind that you will learn a lot by doing all your assignment carefully. Review the stated objectives. Don’t proceed to the next unit until you are sure you have understood the previous unit. Keep to your schedules of studying and assignments. Review the course and prepare yourself for the final examination. Tutors and Tutorials There are 8 hours of effective tutorial provided in support of this course. Details will be communicated to you together with the name and phone number of your facilitator through the study centre. Your tutor will mark and comment on your assignments, keep a close watch on your progress and any difficulties you might encounter and also provide assistance to you during the course. You must ensure that you submit your assignment as and at when due. You will get a feedback from your tutor as soon as possible to the assignments. Do not hesitate to contact your tutor or study centre on phone or email in case of any of the following circumstances: 17  You do not understand any part of the study units or the assigned reading You have difficulty with the self test or exercises. You have questions or problems with an assignment, tutors comments or grading of an assignment. You are encouraged to attend the tutorials to allow for face to face contact with your tutor and ask questions which you needed answers immediately. It is also an opportunity to discuss any grey area with your tutor. You can equally prepare questions to the tutorial class for meaningful interactions. You are sure to gain a lot from actively participating in the discussion. Best of Luck 18 NSS 323: MATERNAL AND CHILD HEALTH NURSING 1 Module 1 REVIEW OF REPRODUCTIVE SYSTEMS Unit 1: Anatomy and physiology of female reproductive system 1.0 Introduction 2.0 Objectives 3.0 The bony pelvis, the pelvic floor and the fetal skull 3.1The bony pelvis 3.1.1Functions 3.1.2 Pelvic bones 3.1.3 Pelvic joints 3.1.4 Pelvic ligaments 3.1.5 Diameters of the pelvic bones 3.1.6 Types of pelvis 3.2The pelvic floor 3.2.1 Functions 3.2.2Muscle layers 3.2.3Perineal body 3.3The fetal skull 3.3.1 The parts of the fetal skull 3.3.2 Measurements of the fetal skull 3.3.3 Importance of the fetal skull to the midwife 3.3.4 The scalp 3.3.5 The intracranial membranes and sinuses 3.3.6 Moulding 4.0 Conclusion 5.0 Summary 6.0 Teacher’s marked assignment 7.0 References/ a list for further reading 19 1.0 Introduction Welcome to NSS323 (Maternal and Child Health Nursing 1). This is the midwifery aspect of nursing practice that is, the care of women in pregnancy, labor and puerperium. For better understanding and effective midwifery practice and in order to achieve safe motherhood, the midwife, (you) must have sound knowledge and be familiar with the unique anatomical feature of the woman and understand the process of reproduction. Your general knowledge of the anatomy and physiology of the body are equally relevant to this course. In this unit emphasis will be laid on the female pelvis, pelvic floor and the fetal skull. It is believed that the knowledge you shall acquire will enhance your skill in the care of women in childbirth. 2.0 Objectives At the end of this discussion you will be able to do the following: Recognize the unique characteristic features of the female pelvis. Identify abnormalities in the pelvis that can complicate labour and manage them appropriately. Explore the anatomical structure of the pelvic floor muscles for effective management of delivery. Prevent injuries to the fetal skull through skilful conduct of delivery and care after delivery. 3.0 Main Content 3.1. The Bony Pelvis The bony pelvis form the bony canal through which the fetus must pass during the normal birth process. If the canal is of the normal shape, and size, the baby of the normal size will negotiate it without difficulties. but , 20  because pelvis vary in size and shape it is important that the midwife recognizes the normal pelvis so as to be able to detect deviation from the normal. One of the ways of estimating the progress of labor is by assessing the relationship of the fetus to certain pelvic landmarks. 3.1.1.Functions It connects the spine to the lower limbs It protects the female reproductive organs, bladder, the urethra ,colon, rectum and anal canal It allows movement of the body especially walking and running It permits sitting and kneeling It forms a bony passage for the fetus during labor It transmits the weight of the trunk to the legs and holds the two femurs Protects the pelvic organs and to a lesser extent the abdominal contents The Sacrum transmits cauda equina and distributes nerves to various parts of the pelvis 21  Figure 1-1 Bony Pelvis 3.1.2 Pelvic bones: There are four bones in the pelvis Two innominate bones (hip bones), One sacrum and One coccyx Innominate Bones: each innominate bone is composed of three parts - the ilium, ischium and the pubis Ilium – large flared out part Ischium – the thick lower part Pubic bone – forms the anterior part Sacrum is a wedge shaped bone consisting of five fused vertebrae. Upper border of the first sacral vertebral juts forward, known as Sacral Promontory which is the most important landmark in the female pelvis. Anterior surface is concave, referred to as Hollow of the Sacrum. Lateral sacrum extends into a wing or ala. Posterior surface is roughened to receive attachment of muscles. Two pairs of holes, or foramina, pierce the sacrum through which, nerve from the cauda equina emerge to supply pelvic organs. Coccyx is a vestigial tail. It consists of four fused vertebrae forming a small triangular bone. The coccyx bends backwards at this joint during parturition to increase the anterior posterior diameter of the pelvic outlet. 22 3.1.3 Pelvic Joints - there are four pelvic joints One symphysis pubis – formed at the joint of two pubic bones, united by a pad of cartilage known as the symphysis pubis Two (right and left) sacroiliac joints – is the strongest joint in the body articulates sacrum to ilium. Normally there are little or no movements in these joints, but during pregnancy especially towards the end there is a certain degree of movement due to the relaxation of the ligaments of the joints. This may give rise to difficulties in walking and backache, especially the multiparous women. There is little widening during labour , commonly referred to as “give” of the pelvis. One sacrococcygeal joint – join the base of the coccyx to the tip of the sacrum 3.14 Pelvic Ligaments: ligaments bind the joints Inter pubic ligaments at the symphysis pubis Sacroiliac ligaments. Sacrotuberous ligament Sacrococcygeal ligaments. Inguinal ligament 23 Figure 1-2 Posterior View of the Pelvis Division of the Pelvis The pelvis is divided into two parts, the true and the false pelvis. The false is the part above the brim. It has little importance in obstetrics The true pelvis is the bony canal through which fetus must pass during birth. It consists of brim, cavity and outlet. Brim is round except where sacral promontory projects into it. Commencing posteriorly the pelvic brim includes the following important landmarks. 1. Sacral promontory 2. Sacral ala or wing 3. Sacroiliac joints 4. Iliopectineal line 5. Iliopectineal eminence 6. Superior ramus of the pubic bone 7. Upper inner border of the body of the pubic bone 8. Upper inner border of the symphysis pubis 24  3.1.5 Diameters of the pelvis Diameters of the brim Antero-posterior diameter – from sacral promontory to upper most border of symphysis pubis 12cm. A measurement to the posterior border of the upper surface to a point 1.25cm lower is called the obstetrical conjugate, 11cm. It is the available space for the passage of the fetus hence it is called the true conjugate Diagonal conjugate is anteroposterior diameter from the lower border of the symphysis pubis to the centre of the sacral promontory measured vaginally for pelvic assessment 12-13 cm. Oblique diameter – from sacroiliac joint to the iliopectineal eminence on the opposite side (right and left). It measures 12cm Transverse diameter – it is between the points furthest apart on iliopectineal lines and measures 13cm. The fetal head commonly enters in transverse diameter of the pelvic brim Sacrocotyloid diameter – from sacral promontory to the iliopectineal eminence on each side, measures 9 – 9.5 cm The pelvic cavity extends from the pelvic brim above to the outlet below. Anterior wall is formed by pubic bones and 25  symphysis pubis - depth is 4cm. The cavity is circular in shape and is considered to be 12cm all round. Diameter of the outlet: There are two Pelvic outlets: described as Anatomical Outlet and Obstetrical Outlet. The anteroposterior diameter of outlet – from the lower border of the symphysis pubis to the sacrococcygeal joints 13cm The oblique diameter of outlet - from the oburator foramen to the sacrospinous ligament 12cm The transverse diameter of outlet - is taken between two ischial spines 10 -11 cm which is the narrowest diameter of the pelvis Pelvic inclination there is difference in the inclination of the pelvis when the woman is standing, sitting and recumbent position. The inclination of the outlet is 11O, cavity 30O, brim 60O, almost 90O in Negro woman Pelvic planes these are imaginary flat surfaces at the brim, cavity and outlet of the pelvic canal. The fetus will enter at right angle to the plane according to the inclination. Axis of the pelvic canal a line drawn exactly half way between anterior wall and posterior wall of the pelvic canal to the plan of the outlet, cavity and the brim the curve it makes is known as the curve of Carus, the path which the fetus takes as it travels trough the birth canal. 26  Figure 1-3 Diameters of the Pelvis Types of Pelvis Gynaecoid pelvis – ideal pelvis for child bearing Android pelvis – resembles a male pelvis Anthropoid pelvis – has long oval brim in which anteroposterior diameter is longer than transverse diameters. Labor does not present any difficulties but favors occipitoanterior or occipitoposterior positions Platypelloid pelvis - flat with kidney shaped brim 27  Figure 1-4: Types of Pelvis Comparison of Male and Female Pelvis Female pelvis Male pelvis 1. Bones are light and 1. Heavy rough and not so smooth, side walls wide and broad straight, fore-pelvis generous 2. Wide iliac crest 2. Narrow iliac crest 3. Brim almost round 3. Brim is heart shaped 4. Cavity is shallow 4. Cavity deep and funnel shaped 5. Symphysis pubis wide 5. Symphysis pubis is deep 6. Wide transverse outlet 6. Narrow outlet o 7. Sub-pubic arch is 85 to 7. 65o to75o 90o 28  8. Joints movable 8. less movable 9. Sciatic notch wide 9. Sciatic notch narrow 10. Ischial spines blunt 10.Ischial Spines shaped 3.2. The pelvic floor The pelvic floor is formed by the soft tissues that fill the outlet of the pelvis. It forms a strong diaphragm of muscle sling from the walls of the pelvis. The pelvic floor is made up of 1. The Skin 2. Subcutaneous Fat 3. Superficial Muscles 4. Deep Muscles 5. Pelvic Fascia 6. Peritoneum The urethra, vagina and the anal canal pierce through it 29  Figure 1-5 Pelvic Floor 3.2.1.Functions: Supports the weight of the abdominal and pelvic organs Responsible for the function of the menstruation and defecation and plays an important part in sexual intercourse Influence passive movement of the fetus during childbirth 3.2.2.Muscle Layers Superficial Layers consists of five muscles: 1. The external and sphincter muscle 2. The transverse perineal muscle 3. The bulbocavernous muscle 4. The ichiocavernous muscle 5. The membrane sphincter of urethra The Deep Layer is composed of three parts of muscle which together are known as the Levator Ani Muscles (left and right): 1. Pubococcygeal muscle 30  2. Iliococcygeal muscle 3. Ischiococcygeal muscle 3.2.3.Perineal body is a pyramid of muscles and fibrous tissue between vagina and rectum. Perineal body measures 4cm in each direction Injury to the pelvic floor Overstretching of the muscles Laceration –1st 2nd &3rd degree tears 3.3 The fetal skull The bones of the skull develop from membranes, ossification starts as early as the 5th week following conception. At term ossification is almost complete except for the thin lines of membranes separating the bones from each other known as the sutures. Ossification of the skull is not complete until early adulthood. 3.3.1 The part of the fetal skull 3.3.1.1 The vault: Is from the line from the nape of the neck to the orbital ridge. The vault is made up of 5 bones and two enter into the lateral wall. These are: 2 Frontal bones 2 Parietal bones: 1 Occipital bone 2 Temporal bones and the wings of the sphenoid bones form the side wall of the skull. 3.3.1.2 The face: This area extends from the orbital ridge to the junction of the neck with the chin. It is composed of 14 fused bones. 3.3.1.3 The base: These bones are also firmly united and help to protect the brain. 31 3.3.1.4 The Sutures These are membranous lines found at the junction between the bones of the vault. There are four important sutures on the vault where ossification has not been completed. The Frontal Suture: Separates the two frontal bones, it extends from the root of the nose to the bregma. The Coronal Suture: Separates the frontal and the parietal bones. Sagittal Suture: Separates the two parietal bones. Lambdoidal suture: Separates the occipital and the parietal bones. Others are the sutures that separate the parietal bones from the temporal bones. 3.3.1.5 The Fontanelles Fontanelles are formed where two or more sutures meet between the bones. There are 6 sutures on the vault but only two are of importance. These are: 1. Anterior Fontanelle (or bregma): Formed at the junction of the Sagittal, Fontal, and coronal sutures. It is a diamond shaped membranous space. It has four angles which correspond with the entry of each suture. It is about 3-4cm long and 1.5cm wide. It is a valuable aid in vaginal examination to determining the position. Cerebral pulsation can be felt through it and it is a guide to baby’s health – It bulges in brain infection or increase pressure and depressed in dehydration. Closes 18-24months after birth. 2. The Posterior fontanell – (lambda): Formed at the junction of the sagittal and lambdoidal sutures. It is a small triangular membranous space. It is felt on vaginal examination during labour in a well flexed head. It closes at 6 weeks after birth. 3.3.1.6 The region of the fetal skull 1. Vertex 2. Face 32  3. Brow (Sinciput) 4. Occiput Other regions are: Glabella – is the bridge of the nose, between the eyebrows. Bregma – anterior fontanelle Lambda – Posterior fontanelle Mentum – Chin. Figure 1-6 : Fetal Skull 3.3.2 Measurements of the fetal skull- 3.3.2.1 Diameter of the fetal skull These are the diameter the birth canal must stretch to allow the head to pass during labour. The lagest being mento vertical 13.5cm. 1. Sub-Occipito Bregmatic (9.5cm) 2. Sub-Occipito Frontal (10cm) 3. Occipito Frontal (11.5m) 4. Mento Vertical (13.5cm) 5. Sub Mento Vertical(11.5) 33  6. Sub-mento Bregmatic (9.5cm) 7. Biparieta (9.5cm) 8. Bitemporal (8.2cm). 3.3.2.2 Circumferences 1. Sub-ocicpito bregmatic: is measurement taken round the occipital protuberance, parietal eminences and the bregma. It is the circumference which passes through the pelvis in a well flexed head 33cm. 2. Occipito Frontal: It is measured through posterior fontanel, parietal eminence and the orbital ridge. It is found in an erect head-military attitude 33-36 cm. 3. Sub-occipito frontal: It is taken round the perimeter of sub- occipito frontal 35cm. 4. Mento vertical: It is measured round the chin up to the vertex. It is found in partly extended head –(Brow). It is the largest diameter of the fetal skull 38 cm. 3.3.2.3 Attitude of the head This determines diameter that pass through the pelvis. 1. Vertex Presentation: A well flexed head. It is the most favourable. engaging diameters are sub-occipito bregmatic of 9.5cm, biparieta 9.5 cm and the circumference entering the brim is sub-occipito bregmatic 33cm. 2. Military attitude – deflexed head. The head is more erect. Engaging diameters are occipito frontal 11.5cm Biparietal 9.5cm bitemporal 8.2cm. and circumference occipito frontal 35cm. 3. Face Presentation: Extended head. The head is completely extended. The engaging diameter is sub-mento bregmatic 9.5cm, Bitemporal 8.2cm. sub-mento vertical of 11.5cm will descent the vaginal orifice. 4. Brow presentation: Partially extended head most unfavourable presentation. Normal delivery is rarely possible if it does not change the attitude. The engaging diameter is mento vertical 13.5cm, Bitemporal 8.2cm and circumference is mento vertical 38cm. 34 3.3.3 Importance of the fetal skull to the midwife 1. It contains the delicate brain and about 95% of babies present by head. 2. Sound knowledge of fetal diameter and measurement cause least problems during labour and delivery through diagnosis of abnormalities presentation and position, also disproportion between the fetal head and the pelvis can be easily recognized. 3. Delivery can be conducted with minimal injuries to the mother and baby. 4. It is large in comparison with the fetal body and true pelvis; some adaptation has to be made between the head and the pelvis. 5. The head is the most difficult part to be delivered either it comes first or last. 3.3.4 The scalp The scalp of the fetus consists of five layers. 1. The skin 2. A subcutaneous tissue: Contains blood vessels and hair follicles. Is the part where caput succedaneum is formed. 3. A layer of Tendon – Galea 4. A loose layer of alveolar tissue. Limits movement of the scalp over the skull. 5. The pericranium – is the periosteum of the cranial bones which covers the outer surface, and is adherent to their edge. Cephalhaematoma is limited to the layer over the bones where it lays because it is attached to the edge of the bone. 35 3.3.5 The intracranial membranes and sinuses Figure 1-7 Cross-section of the fetal skull intracranial membranes and sinuses Figure 1-8 Coronal section of the fetal skull showing intracranial membranes and sinuses 36  The skull contains delicate membranous structure which is liable to damage during delivery especially if subjected to abnormal molding. Structures include: i. Folds of Dura matter and ii. Venous sinuses associated with them. The membrane is in two layers, an outer periosteal layer which is adherent to the skull bones and the inner meningeal layer which covers the outer surface of the brain. The membrane does not only cover the brain but send fibrous partition to divide the brain into compartments. 1. The Falx Cerebri: It is a sickle-shaped fold of membrane which dip down between the two cerebral hemispheres. It runs beneath the frontal and sagittal sutures – (From root of the nose to the internal occipital protuberance). 2. Tentorium Cerebelli: This is a horizontal fold of dura matter situated at the posterior part of the cranial cavity. It lies at right angle to the falx cerebri. It has a horse – shoe shape and forms a tent-like layer between the cerebrum and the cerebellum. It contains large blood vessels or sinus which drains blood from the brain on their way to become the jugular vein of the neck. 3. The superior Longitudinal(Sagittal) Sinus: it runs along the upper part of the falx corebri from front to the back (from root of the nose to the internal occipital protuberance) 4. Inferior Longitudinal (sagittal) Sinus: Runs along the lower part in the same direction. 5. The straight sinus: Is a continuation of the inferior sagittal sinus and drains blood from the great cerebral vain and the inferior sagittal sinus along the junction of falx and the tentorium. The point where it reaches the skull and receives blood from the superior sagittal sinus is known as the confluence of sinus. 6. The Great Cerebral vein of Galen: meet the inferior Sagittal Sinus at the inner end of the junction and where the falx joins the tentorium. 37  7. Lateral Sinuses: These are two in number they pass from the confluence of the sinuses along the outer edge of the tentorum cerebelli and carries blood to the internal jugular veins. During monlding the falx and the tentorium are stretched. The tentorium is most vulnerable to tear near its attachment to the falx – (Tentorial Tears), this leads to bleeding from the great cerebral vain giving rise to intracranial hemorrhage. 3.3.6 Moulding This is the term applied to the change in shape of the fetal head which takes place as it passes through the birth canal. It is brought about by pressure between the fetal skull and the maternal pelvis. It results in compression of the movable bones and elongation of those which are not compressed. Moulding brings about a considerable reduction in the size of the presenting diameters while the diameter at right angle to them elongates. This is possible because of the sutures and fontanelles on the vault which allows slight degree of movement and the bones to override each other. In normal vertex presentation, the biperiatal diameter, sub occipito bregmatic reduce while the mentovertical lengthens. During moulding the anterior parietal bone override the posterior one, the frontal and occipital bones go under the parietal bones. The advantage of moulding is that it is a protective mechanism and prevents compression of the fetal brain, once it is not excessive, too rapid or unfavourable direction. The skull of a preterm baby may mould excessively while that of post mature does not mould which tend to make labour more difficult. In certain types of moulding the internal structure maybe damage given rise to oedema or haemorrhage and congestion may give rise to mild cerebral irritation. This can lead to death or permanent brain damage. These dangerous moulding includes: 1. Excessive moulding: In cases of prolonged labour, due to cephalo pelvic disproportion, prematurity. 38  2. Upward moulding: Occipito posterior position resulting in “face to Pubis” and after coming head of the breech. 3. Rapid moulding: Precipitate labour Rapid compression and decompression result in rupture of cerebral membranes. Any baby with any of this dangerous moulding should be cot – nursed and observed for 24hrs for signs of cerebral irritation. 4.0 Conclusion It is obvious from our discussion that the female pelvis is uniquely designed to favour pregnancy and labour. For the midwife to conduct labour successfully, she needs sound knowledge, skill and technology which must be built on sound knowledge of anatomy and physiology of the human body. The in-depth knowledge of the normal anatomy and physiology of the female will aid early and accurate detection of abnormalities in pregnancy and labour, and she can avert a lot of problems associated with childbirth for the mother and the baby. 5.0 Summary The pelvis consists of four bones, two innominate bones, one sacrum and one coccyx, joined together by very strong fibrous band known as the ligament. The pelvis is divided into the false pelvis, which is of no significance to midwifery practice, and the true pelvis made up of important land marks. The most favourable type of pelvis for delivery is the gynaecoid. The pelvic floor is filled with muscles which hang down like a sling. It forms a good support for the pelvic and abdominal organs. The fetal skull develops from membranes. At birth the bones are separated by membranous lines known as sutures. Where the sutures meet forms the fontanelles which are important landmarks in midwifery. 39 6.0. Tutor’s Marked Assignment 1. Explain why the gynaecoid pelvis is so well suited for child bearing? 2. Describe the changes in the uterus during puerperium 7.0 References/further readings Ojo O.A. and Briggs E.B. (2006) A Textbook for Midwives in the Tropics. 2nd ed. Jaypee Brothers Ltd. New Delhi Fraser D.M. Cooper M.A. and Nolte A.G.W. (2006) Myles Textbook for Midwives, African edition. 40 Unit 2 : The Female Reproductive System 1.0 Introduction 2.0 Objectives 3.0 Main Content 3.1 The Vulva 3.2 The Vaginal 3.3 The Uterus 3.4 The Fallopian Tubes 3.5 The Ovaries 3.6 The Menstrual Cycle 3.6.1 Ovarian Cycle 3.6.2 Uterine Cycle 3.6.3 Minor Discomforts with Menstruation 3.7 Menopause 4.0 Conclusion 5.0 Summary 6.0 Tutor Marked assignment 7.0 Reference/Further Study Introduction In Unit one, we learnt about the bony pelvis, the muscles that cover it and the fetal skull with its external and internal structures. In this unit we shall describe the structures that make up the female reproductive system, their interrelatedness, structurally as well as in functions. These include the external part that comprises all the structures collectively known as the vulva and the internal part which are concerned with fertilization, and development of the fetus, these are the vulva, the vaginal, uterus, fallopian tubes and the ovaries. 41 2.0 Objectives: By the time we finish the discussion in this unit you will be able to:
Describe the various structures of the external female genitalia
Delineate the internal organs of reproduction.
Outline the muscles layers in the uterus that are involved in the control of haemorrhage in labor
Describe the menstrual cycle
Educate older women on menopause and how to cope with the symptoms that accompany it. 3.0 Main Content 3.1 The Vulva The term ‘vulva’ applies to the external female genital organs. It consists of the following structures: The mons veneris (‘mount of venus’) or mons pubis. This is a pad of fat lying over the symphysis pubis. It is covered with pubic hair from the time of puberty. The labia majora (‘greater lip’). Theses are two folds of fat and areolar tissue covered with skin and pubic hair on the outer surface. They arise in the mons veneris and merge into the perineum behind The labia minora (‘lesser lip’) these are two thin folds of skin lying between the labia majora. Anteriorly they divide to enclose the clitoris; posteriorly they fuse, forming the fourchette. The clitoris This is a small rudimentary organ corresponding to the male penis. It is extremely sensitive and highly vascular and plays a part in the orgasm of sexual intercourse. 42  The vestibule This is the area enclosed by the labia minora in which are situated the openings of the urethra and the vagina The urethral orifice this orifice lies 2.5cm posterior to the clitoris. On either side lie the openings of Skene’s ducts, two small blind –ended tubules 0.5cm long running within the urethral wall. The vaginal orifice. This is also known as the introitus of the vagina and occupies the posterior two thirds of the vestibule. The orifice is partially closed by the hymen, a thin membrane that tears during the first sexual intercourse or during the birth of the first child. The remaining tags of hymen are known as the ‘carunculae myrtiformes’ because they are thought to resemble the myrtle berries. Bartholin’s glands there are two small glands that open on either side of the vaginal orifice and lie in the posterior part of the labia majora. They secrete mucus which lubricates the vaginal opening The Perineum The perineum is the area extending from the fourchette to the anus, and forms the base of the perineal body – a triangular mass of connective tissue, muscle, fat, measuring 4cm X 4cm. The perineal body fills the wedge shaped area between the lower ends of the rectum and vagina, and forms a central attachment for the muscles and fascia of pelvic floor. When, during the second stage of labor the perineal body is flattened out by the descending fetal head, the perineum elongates and becomes so thin that it is liable to tear. First degree tear the fourchette only is torn Second degree tear beyond the fourchette and not involving the rectum or anus Third degree tear the anal sphincter is torn, the rectum occasionally 43  The Blood Supply This comes from the internal and external pudendal arteries. The blood drains through corresponding veins Lymphatic Drainage This is mainly via the inguinal glands Nerve Supply This is derived from branches of pudendal nerve. The vaginal nerves supply the erectile tissue of the vestibular bulbs and clitoris and their parasympathetic fibers have a vasodilator effect. Figure 2-1 The Vulva 3.2 The Vagina A muscular tube that extends from the cervix above to the vulva below Functions It allows passage of menstrual flow It receives penis and sperm during sexual intercourse It provides an exit for fetus during delivery. 44  Position running from the vestibule to the cervix Relations Anteriorly bladder and urethra Posteriorly behind the pouch of Douglas , the rectum and the perineal body. Each occupies approximately 1/3rd of the posterior vaginal wall. Lateral Upper 2/3rd are pelvic fascia and the uterus. Lower third are pelvic floor. Superior above the vagina lies the uterus Inferior below the vagina lies the external genitalia Structure posterior wall 10cm, anterior wall 7.5 cm. Cervix projects at right angle into upper part. Upper end is the vault to which the cervix projects. Vaginal walls are pink and thrown into small folds known as rugae. Layers Lining is squamous epithelium. Beneath it, vascular connective tissue. Muscular layer is weak innermost and the outer layer are strong longitudinal fibers. Pelvic fascia surrounds the vagina. Contents No glands in the vagina but moistened by the mucus from cervix. In spite of alkaline mucus vaginal fluid is strongly acidic (pH 4.5) due to the presence of the lactic acid formed by the Dederlein’s bacilli. This acid deters the growth of pathogenic organisms. Blood supply is from branches of internal iliac arteries and branches of uterine arteries Lymphatic drainage is via inguinal, internal iliac and sacral glands. Nerve supply is from Lee Frankanhauser plexus. 3.3 The Uterus The uterus is a thick walled pear shaped hollow, muscular organ lying in the pelvis 45 Functions Prepares for pregnancy each month Shelters the baby Expels the uterine contents after pregnancy Position - the uterus is situated in the cavity of the true pelvis , behind the bladder and in front of the rectum. It leans forward which is kown as anteversion; It bends forwards on itself which is known as anteflexion. When the woman is standing this result in an almost horizontal position with the fundus resting on the bladder. Relations Anterior in front of the uterus lie the uterovesical pouch and bladder Posterior behind the uterus are the rectouterine pouch of Douglas and the rectum. Lateral on either side of the uterus are the broad ligaments, the uterine tubes and the ovaries. Superior above the uterus lie the intestines Inferior below the uterus is the vagina Supports The uterus is supported by the pelvic floor and maintained in position by several ligaments, of which those at the level of the cervix are the most important The Transverse Cervical Ligaments these fan out from the sides of the cervix to the side walls of the pelvis. They are sometimes known as the ‘cardinal ligaments’ or ‘Mackenrodt’s ligaments’ The uterosacral ligaments these pass backwards from the cervix to the sacrum The pubocervical ligaments these pass forwards from the cervix, under the bladder, to the pubic bones. 46 The broad ligaments these are formed from the folds of the peritoneum which are draped over the uterine tubes. They hang down like a curtain and spread from the sides of the uterus to the sides walls of the pelvis The round ligaments. These have little value as a support but tend to maintain the anteverted position of the uterus. They arise from the cornua of the uterus in front of and below the insertion of each uterine tube and pass between the folds of the broad ligament, through the inguinal canal, to be inserted into each labium majus. The ovarian ligament. These also begin at the cornua of the uterus but behind the uterine tubes and pass down between the folds of the broad ligament to the ovaries. It is helpful to note that the round ligament, the uterine tube and the ovarian ligament are very similar in appearance and arise from the same area of the uterus. This makes careful identification important when tubal surgery is undertaken. Structure The non- pregnant uterus is a hollow muscular pear- shaped organ situated in the true pelvis. It is 7.5cm long, 5cm wide and 2.5 cm in depth. The cervix forms the lower one third of the uterus and measures 2.5cm in each direction. The uterus consists of the following parts : The Body or Corpus This makes the upper two thirds of the uterus and is the greater part. The Fundus This is the domed upper wall between the insertions of the uterine tubes. The Cornua These are the upper outer angles of the uterus where the uterine tubes join. The Cavity. This is a potential space between the anterior and posterior walls. It is triangular in shape, the base of the triangle being uppermost 47 The Isthmus this is a narrow area between the cavity and the cervix which is 7cm long. It enlarges during pregnancy and labour to form part of the lower uterine segment The Cervix or Neck. This protrudes into the vagina, the upper half being above the vagina, is known as the supravaginal portion while the lower half is the infravaginal portion. The Internal Os (Mouth) this is the narrow opening between the isthmus and the cervix. The External Os. This is a small round opening at the lower end of the cervix. After childbirth it becomes a transverse slit with an anterior and a posterior lip. The Cervical Canal lies between these two and is a continuation of the uterine cavity. This canal is shaped like a spindle, narrow at each end and wider in the middle. Figure 2-2 the Uterus Layers 48  The uterus has three layers, of which the middle muscle layer is by far the thickest. The Endometrium this layer forms a lining of ciliated epithelium(mucous membrane ) on a base of connective tissues or stroma In the uterine cavity this endometrium is constantly changing in thickness throughout the menstrual cycle. The basal layer does not alter, but provides the foundation from which the upper layers regenerate. The epithelial cells are cubical in shape and dip down to form glands that secrete alkaline mucus. The cervical endometrium does not respond to the hormonal stimuli of the menstrual cycle to the same extent. Here the epithelial cells are tall and columnar in shape and the mucus-secreting glands are branching racemorse glands. The cervical endometrium is thinner than that of the body and is folded into a pattern known as the ‘arbor vitae’ (tree of life). This is thought to assist the passage of the sperm. (the portion of the cervix that protrudes into the vagina is covered with squamous epithelium similar to the squamo-columnar junction and it is known as the intravaginal cervix ,about 1.5 cm. The Myometrium or muscle coat. This layer is thick in the upper part of the uterus and is more sparse in the isthmus and cervix. Its fibers run in all directions and interlace to surround the blood vessels and lymphatics that pass to and from the endometrium. It is this arrangement that facilitate the arrest of haemorrhage after delivery of the baby-“living ligament” The outer layer is formed of longitudinal fibers that are continuous in those of the uterine ligaments and the vagina In the cervix the muscles fibers embedded in collagen fibers, which enable it to stretch in labor. 49  The Perimetrium. This is a double serous membrane , and extension of the peritoneum, which is draped over the uterus, covering all but a narrow strip on either side and the anterior wall of the supravaginal cervix from where it is reflected up over the bladder Blood supply Uterine artery which is a branch of internal iliac artery. Ovarian artery a branch of abdominal aorta supply ovary and fallopian tube ad join with uterine artery Lymphatic drainage Lymph is drained from uterine body to internal iliac glands mainly Nerve supply Mainly from autonomic, sympathetic and parasympathetic nervous system via Lee Frankenhauser’s plexus or pelvic plexus Figure 2-3 The Sagittal Section of the Female Reproductive System 50 3.4 The Fallopian Tubes Functions Propels the ovum towards uterus , receives spermatozoa, provides site for fertilization. Supplies nutrition to the fertilized ovum during its travel to the uterus Position Extends laterally from the cornua of the uterus –arches over the ovaries with the finbriated ends hanging near ovaries to receive the ovum Relations Anterior, posterior and superior are the peritoneal cavity and intestines Lateral – sidewalls of the pelvisd Inferior – broad ligaments and ovaries lie below the tubes Medial – uterus lies between fallopian tubes Supports fallopian tubes are held in place by their attachments to the uterus Structure each tube measures 10cm long ,lumen of the tube provides open pathway from outside to the peritoneal cavity. The fallopian tube has four portions 1. The Intestinal portion – 1.25cm inside uterine wall lumen 1mm wide 2. The Isthmus - narrow part 2,.5cm from cornua of the uterus 3. The Ampulla – wider portion 5cm longit extends from the isthmus to the infundibulum usually fertilization takes place here 4. The Infundibulum – funnel shaped finged and which is attached to the ovary. It is about 2.5 cm long; one is known as the fimbrae. One of it extends to the ovary and is known as the fimbria ovarica 51  Layers - Lining in mucus membrane - ciliated cubical epithelium. Beneath this vascular, connective tissue, muscular layer and covering is peritoneum. Blood supply - from uterine and ovarian arteries by the corresponding vein Lymphatic drainage is to lumbar glands Nerve supply - from ovarian plexus 3.5 The Ovaries Functions The ovaries produce ova for procreation and the hormones estrogen and progesterone Position The ovaries are attached to the back of the broad ligaments within the peritoneal cavity Relations Anterior the ovaries and the broad ligaments Posterior the ovaries and the intestines Lateral the ovaries and the infundibulopelvic ligaments and the side walls of the pelvis Superior the ovaries and the uterine tubes Medial the ovaries lie between the uterus and the ovarian ligament Supports The ovary is attached to the broad ligament but is supported from above by the ovarian ligament medially and the infundibulopelvic ligaments laterally. Structure The ovary is composed of a medulla and cortex covered with germinal epithelium The Medulla. This is the supporting framework which is made up of fibrous tissue; the ovarian blood vessels, lymphatics and nerve travels through it. The hilum where these vessels enter lies just where the ovary is 52  attached to the broad ligament and this area is called the mesovarium. The Cortex. This is the functioning part of the ovary. It contains the ovarian follicles in different stages of development, surrounded by stroma. The outer layer is formed of fibrous tissue known as the tunica albuginea. Over this lies the germinal epithelium, which is a modification of the peritoneum. Blood Supply The blood supply is from the ovarian arteries and drains by the ovarian veins. The right ovarian vein joins the inferior vena cava, but the left returns its blood to the left renal vein Lymphatic drainage--This is to the lumbar glands Nerve supply--This is from the ovarian plexus 3.6 The Menstrual Cycle The reproductive phase of a women’s life begins at puberty until menopause and it is associated with regular menstrual flow. The onset of the first menstrual period marks sexual maturity and is known as menache. It signals the beginning of series of periodically recurrent changes in the hormonal status of the female, which causes build up and shedding of the endometrium Menache usually occurs between the ages 10 -16. Menstruation occurs once a month, averagely it is taken to be every 28 days and recurs regularly from puberty until menopause, though the length may vary with individuals, counting from day 1 of the menses. The flow last about 3-5 days with approximately 50 -100mls of blood. Menstruation is in two cycles. The Ovarian Cycle 53  During the follicular phase, FSH stimulate the primodial follicles in the ovary, which respond by secreting oestrogen. (This prepares the uterine lining for arrival and implantation of the ovum). The ovarian cortex contains about 200,000 primordial follicles at birth. The later become graafian follides. From puberty onwards certain follicles enlarge and one matures each month to librate an ovum. The increasing level of oestrogen signals the hypothalamus to stop producing FSH, hence progesterone surge takes place which results in production of LH. This enhances the maturation of the follicles which causes rupture of the follicle on the 14th day results in ovulation. This is followed by the luteal phase which begins with ovulation and ends with the start of the menstrual flow. The ruptured follicle continue to produce LH, it becomes, yellowish, increases in size to form the corpus Luteum (Yellow body). Progesterone level remains high. If the ovum is not fertilized by 48 hrs the hormonal levels drop and the endometrium begins to shed, this signals menstrual flow. However if fertilization takes place, the corpus luteum continue to secrete progesterone and oestrogen which maintain the endometrium until the placenta takes over. 54  Figure 2-4 The Menstrual Cycle Uterine Cycle/Menstrual Cycle Menstrual cycle is described in phases. Proliferative Phase (Resting Stage) This phase begins immediately the menstruation stops. The first 2-3 days is a stage of repair of the endometrium sometimes referred to as Regenerative Phase, during this stage new endometrium is reformed. Proliferature phase last until ovulation. The endometrium is ready to received ovum. It is under the control of hormone, there is ripening of the granfian follicles which secrete oestrogen in large quantity, under the influence of the FSH from the anterior pituitary gland. The next level get to a peak it inhibit production of FSH. At the same time one graafian follicle would have mature and moves to the surface of the ovary. It bursts and discharges an ovum. This process is known as Ovulation, and takes 55 place about the 14 days before the next menses. As ovulation approaches, rising oestrogen level causes the cervical mucus to become thin, clear and elastic, this elasticity (spinnbarkheit) enhances the sperms motility and increases the female’s fertility. Oestrogen causes the endometrium to become thick, so at the end of this phase, the structure of the endometrium consists of three layers: Basal layer, Functioning layer (surface layer), and Cuboidal ciliated epithelial layer. Secretory Phase: This follows ovulation and is under the influence of progesterone and oestrogen. Increase in the progesterone level and development of corpus luteum further increases thickening of the endometrium and become softer. The lining become more vascular and ready to received fertilized ovum – layer increases to 3.5mm. If fertilization and implantation occurs, progesterone level continues to increase. This inhibits the maturation of another follicle. When the level of progesterone reaches it’s peak and no fertilized ovum, production of LH is inhibited. The corpus luleum degenerates and atrophies resulting in sudden drop in the progesterone level which brings about menstrual flow as a reaction to shrinking and shedding from the uterine wall. Menstrual Phase: This phase is characterized by uterine bleeding and shedding of the endometrial lining. After 14 days of corpus luteum and no fertilization result in sudden drop of progesterone and oestrogen, the functioning layer is shed off with the epithelial layer and expelled by the muscular contraction of the uterine muscle. This tissues plus bleeding from the ruptured blood vessels form the menstrual flow. It last for about 3- 5 days. Total blood loss 50-100 mls. The fibrinolysis present in the blood prevents clotting. 56 The contents of menstrual blood are endometrial lining, blood from capillaries mucus and dead ovum. Regularity of menses depends on hormonal changes associated with ovulation, which are under the influence of changes in the anterior pituitary gland and some emotional factors. The life span of the ovum is 24-48hrs. Women are in the most fertile state about 14 days before the next menses. The secretary phase is more or less constant in length but the proliferative and menstrual phases may vary. Some women experience little or no discomfort during menstrual cycle while some experience full blown premenstrual syndrome (PMS) which may occur several days before the onset and last a few days after. Slight pelvic pain may accompany ovulation, known as Mittl schemer’s syndrome, which may be due to stretching of the ovarian capsule, slight bleeding into the peritorieal cavity or peristalsis in the fallopian tubes – characterized by the following. Minor Discomforts Associated With Menstruation 1. Headache, bloating, largely brought about by relaxation of smooth muscle caused by progesterone. 2. Heaviness of the lower abdomen and legs. 3. Tenderness and swelling of the breasts nipples fluids on the breast. 4. Visual disturbance, some women may become sleepy. 5. Impaired judgment careless mistakes especially during secretary phase. Increased activity of the skin Increased amount of vaginal discharge and Increased frequency of micturation. 6. Nervous tension, irritability, depression. 7. Craving for salty and sweet things. 57  8. Digestive disturbances e.g. epigastric discomfort, heartburn and constipation. Treatment Analgesic, reduced sodium in diet, avoidance of caffeine and stress – activities e.g. walking, emotional support,and heat therapy, in severe cases refer (physician). 3.7 Menopause This is the end of the reproductive period of a woman. This occurs between the ages of 45 and 50. The ovarian hormone being gradually withdrawn and ovulation ceases. The menopause is thought to take about 2 years The time is known as climacteric. The effect of this upon various systems of the body: it causes certain physical symptoms Hot flush, 1. Palpitation, tendency to obesity 2. Vasomotor expressed as hot flashes 3. Psychological depression , anxiety mood swing etc These are all physiological changes but are associated with psychological actions. Women should not expect ill health and they should be encouraged to live active interesting lives. For profuse, prolong and irregular bleeding, medical aid should be sought to exclude the possibility of malignancy. 4.0 Conclusion The female reproductive system plays a significant role in reproduction. It forms a channel through which the ovum released at ovulation travels to fuse with the spermatozoa. The uterine muscle layers are specially designed to prepare, receive, accommodate, nurture zygote, and expel the fetus when at term by its contractile action. 58 The tranquility of the uterus due to the action of pregnancy hormones e.g. progesterone allows the uterus to shelter the fetus to mature before expulsion. From the discussion we can also conclude that the woman has a reproductive life span when she can bear children. A woman does not remain fertile for life. 5.0 Summary The female reproductive system can be divided into two parts, the external genitalia known as the vulva which comprises of the vaginal, uterus, uterine tubes and the ovary. Each of these structures plays different roles but their focus is to bring about process of fertilization and delivery at the end of pregnancy. Menstruation is the discharge of blood from the uterus as a response to progesterone hormonal level in the blood stream. Every month the uterus is prepared ready to receive fertilized ovum. In the absence of pregnancy the corpus lueteum degenerate and menses occurs 14 days before the next one. 6.0 Tutor Marked Assignment Identify the structures of the external female reproductive organs. Briefly explain with diagram the phases of menstrual cycle. 7.0. References and Further Studies Fraser D.M. Cooper M.A. and Nolte A.G.W. (2006) Myles Textbook for Midwives African Edition Thresyamma C.P. (2002) A Guide to Midwifery Students. Jaypee Brothers Medical Publisher (P) Ltd. New Delhi. Ojo O.A. and Briggs E.B. (2006) A Textbook for Midwives in the Tropics. 2nd ed. Jaypee Brothers Ltd. New Delhi DiDona N.A. and Marks M.G. (1996) Introductory Maternal Newborn Nursing Lippincott 59 60 Unit 3: The Male Reproductive System 1.0 Introduction 2.0 Objectives 3.0 Main Content 3.1 External organs 3.1.1The penis 3.1.2 The scrotum 3.2 The internal organs 3.2.1 Testes 3.2.2 Epididymis 3.2.3 Vas deference 3.2.4 Seminar vesicle 3.2.5 Ejaculatory duct 3.2.6 Prostate gland 3.2.7 Cowper’s gland 3.2.8The urethra 3.3 The male hormones 3.4 Formation of spermatozoa 3.5 The sperm 4.0 Conclusion 5.0 Summary 6.0 Tutor Marked Assignment 7.0 References/Further reading 1.0 Introduction In the preceding unit we described the female reproductive organs and the interrelatedness in their physiology that brings about the release of the ovum during the ovarian cycle. The male reproductive system too plays a very important role in reproduction. We shall now discuss the anatomy of the male organs, their functions, and production of spermatozoon which unite with the ovum that result in a new life. 2.0 Objectives 61 At the end of this unit you will be able to Describe all the organs of the male reproductive system Explain the process of spermatogenesis Appreciate the role of he male organ in reproduction. 3.0 Main Content The Male Reproductive System The male reproductive system is made up two main parts. 1. The External 2. The internal parts 3.1 The External Organs 3.1.1. The Penis It has its root in the perineum with the lower 2/3rd of the body suspended outside in front of the scrotal sac. It is made up of three bundles of spong-like erectitle tissues: i. 2 the corporal cavernosa on the lateral columns in front of the urethra ii. 1 The corpus spongiosum on the posterior column which contains the urethra enclosed in a firm sheath of firm tissue with rich blood supply and covered with the skin. The skin continues with the scrotum and the groins. The skin double fold backwards on itself at the glans penis to form the prepuce (foreskin) which is usually removed during circumcision. The penis transmites a portion of the urethra which acts as a passage for semen as well as excretion of urine… During sexual excitement the penis becomes larger, rounder, firmer and erect to be able to penetrate and deposit semen near the cervix. Stimulation of the nervous system increases blood supply to the organ. This erections tart at puberty and may result in wet dream in adolescent boy. There is a small sphincter in the urethra which prevent semen from entering the bladder and urine from the urethra mixing with the semen during intercourse. 62 3.1.2. The Scrotum It is a sensitive pouch-like sac covered with wrinkled skin and hair from which the penis hangs. It lies in front of the thighs, behind the penis and is thickly pigmented. The scrotum is divided by a fibrous septum called Dartos muscle into two cavities each of which contain a testis epididymis and initial portion of the vas deference. The muscles contract in cold weather and relax in hot weather to ensure normal temperature around the testes. Next to the clartos muscle lies the cremaster muscle and fascia. It protects the testes from injuries. Figure3-1 The Cross Section of the Male Reproductive System 3.2. The Internal Organs 3.2.1. The Testes The testes are the male reproductive glands (Gonads), equivalent to the female ovaries. They are formed in the fetal abdomen at the lumber region just below the kidneys at about 28th week of gestation. The testes descend into the scrotum via the right and left inguinal canal, toward the end of pregnancy. They are suspended by spermatic ducts. The testis is ovoid in shape & white in colour. Size: 4-4.5cm long, 2.5cm wide 3cm thick and 10-14gm or more in weight, depending on the heftiness of the individual man structure. Each testis is surrounded by 3 coverings of glandula tissue. 63  1. Tunica Vaginalis: This is the thick outer covering and is a double fold of a down growth of the abdominal and pelvic peritoneum brought down with the descending testis when it descends. The visceral layer surrounds the testes while the parietal lines the Germaters muscle. 2. Tunica Albuginea: This is a fibrous tissue coat surrounding the testes under the vaginalis. Ingrowths of albuginea form septa dividing the glandular tissue into 200-400 lobules. Each contains convulated seminiferous tubules lined with germinal epithelium which produce sperm (Spermatogenesis) from puberty. Surrounding the tabula are connective tissue stroma which contains cluders dendox cells (Leydig cells) cells which secrete testosterone. 3. Tunica Vasculosa: This consists of network of capillaries supported by delicate connective tissues. They surround each lobule of the testes. The testes must be kept below body temperature in order to function properly, hence they are situated outside the body. Inflammation of the testis is known as Ochitis. Cryptorchidism: Complete failure of the testes to descend into the scrotum. Such testes are destroyed due to high body temperature. 3.2.2. The Epididymis This is a fine convoluted tubule about 6 metre in length connecting the testis and the vas defense. It is found at the posterior aspect of the testis. It produces substance which stimulates the development of the sperm. The sperms are stored here to become mature and motile 3.2.3. Vas Deferens A continuation of the epididymis, commences at the tail and, passes upwards behind the testis through the inguinal canal and ascends medially towards the posterior wall of the bladder; enter the pelvic cavity where it connects with the seminal duct. These are the tubes ligated during vasectomy; it is about 450cmlong. The vas deferens duct is surrounded by smooth muscle the peristaltic 64 contraction of the smooth muscle tissue help propel sperm cells through the duct. 3.2.4. Seminal Vesicles These are small irregular Pyramid shaped sacs lying between the base of the bladder and the rectum. They are about 5cm long. They are composed of columnar epithelium, muscle and fibrous tissues. They secrete yellowish fluids which is an essential component of seminal fluid. Each vesicle opens into the seminal duct which joins the vas deferens on the corresponding side of the ejaculatory duct. The fluid contains fructose and other nutrients to nourish the sperm. Forms nutrients to nourish the sperm constitute about 60% of the semen and give it its co lour. 3.2.5. Ejaculatory Ducts They are two small muscular ducts about 2cm long. Pass through the prostate gland and connects with the vas deferens and opens into the urethra. They carry the spermatozoa and seminal fluid to the urethra. 3.2.6. Prostate Gland Is a cone shaped structure, about the size of a walnut. 4cm long, 3cm wide, 2cm deep and 8g in weight. It lies below the bladder, surrounding the upper part of the urethra in direct contact with the neck of bladder. It is composed of glandular tissue and involuntary (Columnar epithelium) muscle enclosed in fibrous capsule. It secretes alkaline fluid which makes up 30% of semen. It is added to the sperm, and the muscle fiber aids ejaculation of the sperm. The fluid neutralizes the acidity of the vagina during intercourse. It gives the characteristic odour. Enlargement of prostate gland in old men causes urine retention. 3.2.7. Cowper’s Glands (Bulbo Urethral Glands) 65  They are two small glands about the size of a cowpea, yellow in colour and lie below the prostate gland. The ducts about 3cm long open into the urethra before reaching the penile portion. The secretion is alkaline in nature and is added to the seminal fluids and also help to lubricate the penis during sexual activities. 3.2.8. The Urethra Is a tube, about 8 cm long, travels from the bladder to the tip of the penis. Urine passes through it as well as a passage for semen during sexual intercourse. The muscle at the neck of the bladder closes it up to prevent semen from entering the bladder during sexual intercourse. 3.3. The Male Hormones The hypothalamus produces Gonadotrophin releasing factors which stimulate the anterior pituitary gland to produce follicle stimulating hormones (FSH) and luteinising hormone (LH). The FSH act on the seminiferous tubule to bring about production of sperm, while LH acts on the interstitial cells (Leydig) within the testes, which produce testosterone. Testosterone is responsible for secondary sex characteristics - i.e. deepening of the voice, growth of the genitalia and growth of hair on the chest pubis, axilla and face, muscle mass development, strengthening of the bones and enlargement of the penis, scrotum, testes, prostate gland and seminal vesicle and all attribute to the influence of testosterone. 3.4. Formation of the Spermatozoa: Spermatogenes (Spermatogenesis) Production of sperm starts at puberty and continues throughout life. Production takes place in the seminiferous tubules under the influence of FSH & testosterone. It takes some weeks (about 3 months) to mature. The matured sperm are stored in the epididymis. About 2-5mls of semen is deposited at each ejaculation and 1ml contain about 100 million sperm/ml which move at a speed of approximately 2-3mm per minute. 66  The scrotum produces an ideal temperature for production of sperm. Significant decrease or increase in temperature affects the testes ability to produce sperm.Illness, wearing of tight clothing, undue heat and exercise affect the temperature and can impair sprrmatogenesis. 3.5 Sperm The sperm is about 0.05mmlong. only visible under microscope. It has a head, body and a fine long mobile tail which lashes to propel the sperm along. The tip of the head is covered by an acrosome which contains enzyme that dissolves the covering of the ovum in order to penetrate it. 4.0 Conclusion The male reproductive organ is equally important as that of the female. The unit has taken you through the structures that constitute the male reproductive system, the male hormones and production of spermatogenesis. All the organs work together to allow the male gonads to produce healthy sperm that are capable of fertilizing the female ovum. 5.0 Summary This system is divided into 2 parts, the external and the internal. The external comprises the penis and scrotum. The internal structure lies within the body. The scrotum houses the testes while testes houses seminiferous tubules and gonads. Seminiferous cells contain the sperm cells in various stages of developments. The epididymis provides area for maturation of the sperm and acts as a reservoir for matured spermatozoa. Seminal fluids provide nutrition that aids motility and fertility ability of the sperm. Cowper’s glands secrete alkaline fluid which neutralizes acidic vaginal secretions. For effective performance of its function the testes has to be at lower temperature than that of the body. 6.0 Tutor Marked Assignment. Describe the male external organs Explain spermatogenesis 67 7.0 References/further readings Ojo O.A. and Briggs E.B. (2006) A Textbook for Midwives in the Tropics. 2nd ed. Jaypee Brothers Ltd. New Delhi Fraser D.M. Cooper M.A. and Nolte A.G.W. (2006) Myles Textbook for Midwives, African edition. Unit 4: Fetal Development, Placenta Development and Fetal Circulation 1.0 Introduction 2.0 Objectives 3.0 Main Content 3.1 Fetal and Placental Development and Fetal Circulation 3.1.1 Fertilization 3.1.2 Formation of the decidua 3.1.3 Growth and development of the fertilized ovum 3.1.4 Summary of growth and development 3.2 The placenta development 3.2.1 Placenta at term 3.2.2 Functions of the placenta 3.2.3 The membranes 68  3.2.4 The umbilical cord 3.3 The fetal circulation 3.3.1 Temporary structure 3.3.2 The course of circulation 3.3.3 Changes in fetal circulation at birth 4.0 Conclusion 5.0 Summary 6.0 Tutor Marked Assignment 7.0 References/ Further study 1.0 Introduction In the previous three units we have been discussing how the organs of reproduction facilitate reproduction, female and male alike. We also learnt that except these organs are in good state of health the smooth process of the function may be inhibited. Now we shall go into the process of fetal development, maturation, survival in- utero. I hope you will enjoy this unit that brings to our awareness the way we started the journey of life. 2.0 Objectives By the time we finish the discussion in this unit, you will Gain insight into how conception takes place. Be able to explain how the organs of the body develop. Understand why some are born with congenital abnormalities Appreciate the factors responsible for maldevelopment and assist in preventing them. 69 3.0 Main Content 3.1 Fetal and Placental Development and Fetal Circulation 3.1.1 Fertilization This is the fusion of the ovum and the spermatozoon, and it initiates the beginning of a new life. During ovulation the ovum which is released from the ovary is propelled towards the fallopian tube. During intercourse millions of spermatozoa released and deposited at the upper vaginal travel towards the fallopian tube. Aided by the alkaline cervical mucous secretion at the time of ovulation they travel to the fallopian tubes where they meet the ovum just released during ovulation. Several hundred of them bind the ovum (zonal pellucida) but only one spermatozoon can fertilize at a time. The sperm are viable for 24-72 hours within the female reproductive system. As soon as fusion occurs between the spermatozoon and the nucleus of the ovum, the zonal pellucida goes through chemical changes releases an enzyme which make it impossible for other spermatozoa to penetrate. The membrane of the spermatozoon breaks; the tail separates and disappears, living a naked male pronucleus. The fertilized ovum is known as the ZYGOTE. A new individual has begun its journey till death. Within a few hours of fertilization process of rapid mitotic cell division, known as cleavage starts (2nd cleavage which has been arrested at metaphase resumes ending in Haploid number). Within 3 days a solid mass of uniform cells of 16 segments has formed known as the MORULA (Mulberry). During this period the egg is gently propelled from the ampulla tube where fertilization took place, along the tube towards the uterine cavity with its peristalsis and wavelike motion of cilia. With further development central cavity is formed in the morula and the cell is now moved to one pole, aggregate to form the inner cell mass from where the embryo and the amnion will be formed, and the fluid on the other pole. At this stage the ovum is known as the BLASTOCYST, or BLASTULA. (By 4½ days the blastocyst has divided up to 100 cells and within approximately 6 days, reaches the decidua of the uterus where implantation takes place.). The outer wall of the 70 blastocyst is composed of fluid –filled cavity of (Blastocele surrounded by a single layer of cells) blastocele called TROPHOBLAST from where the placenta and the chorion are formed. It oxidizes the endometrial vascular walls, it is capable of eating through the decidua and embeds, and it provides the growing embryo with link to maternal circulation for transportation of nutrients and Oxygen. At this stage the zonal pellicuda has disappeared and the Zygote is ready to embed. A layer of cells connect the inner cell mass to the trophoblast, this forms the body stalk. Implantation (Embedding): Nidation Sites vary from one pregnancy to another, but most often the trophoblast implants itself in the upper segment of the uterus usually within seven days. Some women may experience slight vaginal bleeding during implantation (implantation bleeding). As soon as the trophoblast touches the already prepared uterus especially with the side of the inner cell mass lies free for 2-3 days, it sticks to the endometrium and secretes an enzyme which erodes the endometrial cells and begins to burrow into the endometrium. Three to four days after implantation, the blastocyst has penetrated very far and completely embedded and the uterine epithelium covered the entrance the trophoblast has proliferated and penetrated deeply in the uterus. This takes place by 11th day after ovulation. The stoma of the endometrium now reacts to the invasion by accumulating glycogen and lipid and the area become highly vascularised. The depression formed is filled up with maternal blood which surrounds the ovum. At this time the endometrium is referred to as the decidua. 3.1.2 Formation of the Decidua After fertilization the endometrium of the uterus is known as the decidua. Oestrogen increases the size to about 4 times of its pre- gravid thickness, the corpus Luteum, and produce large amount of progesterone which increases the secretion of the endometrial 71 glands and increases the blood vessels. So it makes the endometrium to be softer, spongy and vascular for the fertilized ovum to embed and nourishes itself. The decidua is transformed into 3 layers. i. The Basal layer (Basement): This lies immediately above the myometrium. It remains unchanged in itself but regenerate the new endometrium after delivery. ii. The functional layer (cavernous layer): it consists of tortuous glands rich in secretions. The stoma cells are enlarged in what is known as the decidua reaction which provides defense against excessive invasion by the syncytiotrophoblast and limit it to this spongy layer. It provides anchor for the placenta and allows it to have access to nutrition and 0xygen. It is the functioning layer. iii. The compact layer it covers the surface of the decidua and composed of closely packed stoma cells, polygonal in shape and it contains necks of glands. The blastocyst forms a small nodule in the decidua which bulges out into the uterine cavity progressively as it continues to enlarge and divides the decidua into three areas. 1. Decidua Basalis: This is the area of the decidua underneath the developing ovum. 2. Decidua capsularis: the area which covers the ovum. 3. Decidua vera (Perietal) (True Decidua): This lies in the remainder of the uterine cavity. As development continues the ovum grows and completely fill up the uterine cavity, at about the 12th week the decidua capsularis comes in contact with the decidua vera, it fuses with it and degenerates. 3.1.3 Growth and Development of the Fertilised Ovum During the first 8 weeks of pregnancy, embryonic tissues and the surrounding supportive structures are formed simultaneously. It is during this period that the embryo is at greatest risk for malformation. From the 8th week through the end of pregnancy, the 72 embryo is known as the FETUS. The supportive structures that nourish and maintain the growing fetus are called the fetal membranes. These include the yolk sac, amnion, chorion, decidua and the placenta. The Trophoblast As development continues small projections begin to appear all over the surface of the blastocyst known as the tropoblast, becoming most prolific at the area of contact – area of inner cell mass. The trophoblast differentiates into layers. i. The outer syncytiotropoblast (syncitium): it is capable of breaking the decidua tissue during embedding. It erodes the wall of the blood vessels, making nutrient in the maternal blood accessible to the developing embryo. It acts as a protective layer between the chorionic villi. ii. Cytotrophoblast: This is a well defined single layer of cells which produce Human Chorionic gonadotrophin (HCG). It informs the corpus Luteum that pregnancy has begun, so as to continue to produce progesterone and oestrogen. The progesterone maintain the integrity of the decidua so that shedding does not take place (menstruation is suppressed), while the high level of oestrogen suppresses the production of FSH. The HCG is produced in high level in the first trimester and it is the basis for pregnancy test. iii. The Mesoderm: Consist of loose connective tissue. It is continuous with that in the inner cell mass where they join in the body stalk which later develops into the umbilical cord. The trophoblast later form finger like process called –Primitive villi which develop into placenta and the chorion. The Inner Cell Mass As the trophoblast is developing into the placenta which will nourish the fetus, the inner cell mass is forming the fetus itself, umbilical cord and the amnion. The cells differentiate into three layers each of which will form particular parts of the fetus. 73  1. The Ectoderm: Mainly forms the skin, nervous system, mammary glands salivary glands, Pharynx, nasal passage and crystalline lens of the eyes, certain lining of the mucosa, hair, nails, and enamel of the teeth. The Mesoderm: Forms the bones muscles, circulatory system old vessels Reproductory system (ovary and testes), kidneys, ureters, connective tissues, lymphatic system. The Endoderm: Lines the yolk sac. It forms the Alimentary tract, liver, pancreas, lungs, Bladder thyroid glands. The fetus develops it’s own blood like other organs in the body. The maternal and the fetal blood never mix. During the later weeks (4 wks) the organs like the liver and heart start to function. The three layers together are known as the embryonic plate. Two cavities appear in the inner cell mass one on either sides of the embryonic plate. i. The Amniotic Cavity: this lies on the side of the ectoderm. The cavity which is filled with fluid gradually enlarges and fold round the embryo to enclose it the lining forms the amnion. It later enlarges in the chronic cavity and comes in contact with the chorionic membrane. ii. The Yolk Sac: Lies on the side of the endoderm and provides nourishment for the embryo until the placenta( alimentary tract After birth the remnants of the yolk sac is the vestigial structure in the base of the umbilical cord, known as vitelline duct. The developing of spring is referred as EMBRYO after fertilization up to 8 weeks after which the conceptus is known as FETUS until birth. Summary Of Fetal Development 74 0-4 weeks after conception 20 – 24 weeks Rapid development Most organs become capable of Formation of the embryonic plate functioning Primitive central nervous system forms Periods of sleep and activity Limb buds form Responds to sound Embryo is susceptible to damage from Skin red and wrinkles drugs , radiation and viruses 4 – 8 weeks 26 – 28 weeks Very rapid cell division Survival may be expected if born Head and facial features develop Eyelids reopen All major organs laid down in primitive Respiratory movements form Weighs 1000 – 1200g External genitalia present but sex not distinguishable Early movements Visible on ultrasound from 6 weeks 8 – 12 weeks 28 – 32 weeks Eyelids fuse Begins to store fat and iron Kidney begins to function and the fetus Testes descend into scrotum passes urine from10 weeks Lanugo disappears from face Fetal circulation functioning properly Skin becomes paler and less Sucking and swallowing begins wrinkled Sex apparent Moves freely (not felt by mother) Some primitive reflexes present 0 – 6 cm in length, weighs 30g, spleen produces RBc Face has human feature 12 – 16 weeks 32 – 36 weeks Rapid skeletal development – vsible on Increased fat makes the body more X-ray rounded Meconium present in gut Lanugo disappears from the body Lanugo appears 75 Head haie lengthens Nasal septum and palate fuse Nails reach tips of finger 10 -16 cm in length, weighs 120g Ear cartilage soft Plantar creases visible 3.2 The Placenta Development The survival of the fetus depends on the integrity and efficiency of the placenta. It performs the function which the fetus is unable to perform for itself in-utero. Development: The placenta originates from the tropholastic layer of the fertilized ovum which forms the chorionic villi. The chorionic villi become more profuse in the area which blood supply is richest. That is in the decidual basalis. This part is known as the CHORIONIC FRONDOSUM and it is what later develops into placenta. The capsular decidua later degenerate to form chorionic leave (bald chorium) from where the chorionic membrane is formed. These villi erode the maternal blood vessels opening them up to form a lake of maternal blood in which they float. Opened blood vessels are known as sinuses. Blood filled space is known as the intervilleous space. The maternal blood circulates around the villi slowly enabling it to absorb oxygen and nutrients and excrete waste into it. These are known as Nutritive villi. A few villi are deeply attached to the decidua and are known as Anchoring villi they stabilize the placenta. They lie between the maternal and the fetal blood vessels. Each villus originates from one single steam and it consists of 3 layers of cells mesoderm which contains the blood vessels, inner layer of cytotrophoblast and outer layer of syncytiotrophoblast; so it is impossible for the fetal and maternal blood to mix except when there is damage to the chorionic villi. Villi do not penetrate beyond the functional layer; it stopped by a layer of fibrinoid material in the decidua known as the layer of Nitabuch. By 10 weeks the placenta is completely formed and starts to function. It is initially a soft loose tissue. It becomes more compact as it matures 3.2.1 Placenta At Term The placenta at term is a round flat organ about 20cm in diameter and 2.5cm thick at the centre. It weighs about 1/6th of the baby’s weight at birth. It is made up of chorionic frondosum and blood vessel containing fetal blood and decidua Basalis. It has two surfaces the fetal and maternal surfaces. 76 The Fetal Surface It is smooth, whitish and shiny covered by the amnion and chorion. The cord is attached to it at the centre and the fetal blood vessels can be seen radiating from the insertion of the cord to the edge. The chorion hangs from the edge of the placenta while an amnion can be peeled up to insertion of the cord. The Maternal Surface: This is rough and bluish-red in color. It is made up of chorionic villi arranged in 20 cotyledons or lobes separated by sulci or furrous some small deposit of lime salt can be found on the surface which appear gritty in appearance. This has no clinical significance. The surface is covered by a layer of trophoblastic cells. 3.2.2 Functions Of The Placenta 1. Respiratory: During intrauterine life no pulmonary exchange of gases can take place. The fetus absorbs oxygen from the maternal haemoglobin by processes of simple osmosis and diffusion and gives off carbon-hydroxide into the maternal circulation similarly. 2. Nutritive: All food nutrients required by the fetus for growth and energy are obtained from the mother’s blood in simplest form. Protein for building tissue, glucose for growth and energy, calcium & phosphorus for the bones and teeth, water, vitamins, electrolytes, iron and other minerals for blood formation, growth and various body processes. The Placenta does the selection. The placenta also does the metabolic function of glucose; it stores it as glycogen and converts it to glucose as required. 3. Excretory: All waste products from the fetus are excreted into the mother’s circulation through the placenta. 4. Endocrine: Placenta produces some hormones. a. Human Chorionic Gonadotrophin (HCG): This is a unique hormone in pregnancy produced by the langhans cells of the chorionic villi – cytotrophoblast from its earliest day. It makes the corpus luteum to continue 77  with production of progesterone and Oestrogen until the placenta takes over. It can be detected from about the 30th day of conception and reaches