Nutrition in Infancy PDF

Nutrition in Infancy Introduction Good nutrition during the first 2 years of life is vital for healthy growth and development. Starting good nutrition practices early can help children develop healthy dietary patter...

Nutrition in Infancy Introduction Good nutrition during the first 2 years of life is vital for healthy growth and development. Starting good nutrition practices early can help children develop healthy dietary patterns. www.vision.edu.sa Nutrition in Infancy Who is infant Infant is the child in the first year of his life. www.vision.edu.sa Nutrition in Infancy Infant Nutrition Good nutrition is essential for infant for the following: 1- Survival. 2- Physical growth. 3- Mental development. 4- Health and well-being. www.vision.edu.sa Nutrition in Infancy Nutritional requirements Nutritional requirements for the baby in the first year of life: Fluid: 100-150 ml/kg. Calories: 100 – 120 ml / kg. Protein: 1.5 – 2 g / kg. Premature infants may have increased needs regarding protein, calories and minerals. www.vision.edu.sa Nutrition in Infancy Infant Nutrition Breastfeeding. Formula feeding. Foods and drinks. Vitamins and minerals. www.vision.edu.sa Nutrition in Infancy Breastfeeding WHO recommend exclusive breastfeeding in the first 6 months of life, and then continuing breastfeeding while introducing appropriate complementary foods until your child is 12 months old or older, and should continued beyond first 6 months along with appropriate type of solid food. www.vision.edu.sa Nutrition in Infancy Benefits of breastfeeding Benefits to Baby: Babies who are breastfed have a lower risk of: 1. Asthma. 2. Obesity. 3. Type 1 diabetes. 4. Severe lower respiratory disease. 5. Acute otitis media (ear infections). 6. Sudden infant death syndrome (SIDS). 7. Gastrointestinal infections (diarrhea/vomiting). 8. Necrotizing enterocolitis (NEC) for preterm infants. www.vision.edu.sa Nutrition in Infancy Benefits of breastfeeding Benefits to Mother: Mothers who breastfeed their babies have a lower risk of: 1. Breast cancer. 2. Ovarian cancer. 3. Type 2 diabetes. 4. Hypertension. www.vision.edu.sa Nutrition in Infancy Colostrum For 2-4 days after delivery. 1. Contains more Sodium. 2. High in vitamin A and vitamin K. 3. More protein and IgA than mature milk. 4. Less fat and CHO. Colostrum is followed by transitional milk. Mature milk is established by 4th week after delivery. www.vision.edu.sa Nutrition in Infancy Composition of milk www.vision.edu.sa Nutrition in Infancy Composition of milk www.vision.edu.sa Nutrition in Infancy Composition of milk www.vision.edu.sa Nutrition in Infancy Milk Formula Formula milk, also known as baby formula or infant formula, is usually made from cows' milk that has been treated to make it more suitable for babies. Human-milk substitutes existed before the modern age of formulas. Because some infants could not be fed by their mothers, humans adopted two methods for substitute feedings: 1. The most obvious was the utilization of a surrogate mother (e.g., wet nurse), who would feed the child human milk. 2. The alternative was to feed the child milk obtained from another mammal. The most frequently used sources were the cow, sheep, and goat. www.vision.edu.sa Nutrition in Infancy Milk Formula By the early twentieth century it was clear that cow milk was most likely the best animal-milk base to work from, but that certain modifications were needed to make it safe and palatable for human infants. These modifications included: 1. Removing animal fat and substituting vegetable oils. 2. Diluting the protein content for the newborn's relatively immature renal tubular system. 3. Adding or balancing minerals and vitamins (e.g., adding iron, adjusting the calcium: phosphorus ratio). www.vision.edu.sa Nutrition in Infancy Milk Formula Types of Milk formulas: 1- Cow’s milk-based formula. 2- Iron fortified infant formula. 3- Soy based infant formula. 4- Low iron infant formula. 5- Amino acid based infant formula. 6- Lactose free infant formula. www.vision.edu.sa Nutrition in Infancy Weaning Weaning is the process of switching an infant's diet from breast milk or formula to other foods and fluids. To make the process easier for the child, weaning occur over several weeks or more. www.vision.edu.sa  Nutrition in Infancy Food The American Academy of Pediatrics (AAP) recommends that all infants be exclusively breastfed for about 6 months; that complementary foods be introduced in a timely manner, when the infant is developmentally ready to consume them, at approximately 6 months of age; and that breastfeeding is continued simultaneously with the consumption of complementary foods for at least the first year of life or longer. It is important to assess the developmental stage of the infant, including oral skills and number and type of teeth for chewing. www.vision.edu.sa Nutrition in Infancy www.vision.edu.sa Nutrition in Infancy Food Foods to avoid: 1- Honey. 2- Cow’s milk. 3- Sugar. 4- Artificial sweeteners. 5- Salt. 6- Fried foods, sauces and processed meat. www.vision.edu.sa  Male Genital System The male genital system consists of: - Primary Sex Organ: two TESTES. - Accessory Sex Organs: Excretory Ducts & Accessory Glands Accessory Sex Organs Accessory Glands: seminal vesicle, prostate, bulbo-urethral glands. Excretory Ducts: tubuli recti, rete testis, efferent ductules, epididymis, vas deferens, ampulla of vas deferens, ejaculatory duct and urethra. www.vision.edu.sa  THE TESTIS It is the primary sex organ. It produces sperms (exocrine gland) & testosterone (endocrine gland). It is oval in shape. Each testis is located in one compartment of the scrotum. It has 3 capsules: tunica vasculosa, tunica albuginea and tunica vaginalis. It has 3 coats: Internal spermatic fascia, Cremasteric muscle and fascia & External spermatic fascia. www.vision.edu.sa  Internal Structure of The Testis The Tunica albuginea is a fibrous coat which is thickened posteriorly to form the mediastinum testis. Many septa emerge from the mediastinum and divide the testis into 250 compartments, each of them contains 2-3 seminiferous tubules (60 cm). The beginning of the seminiferous tubule is straight (tubuli recti). The tubuli recti open to form the rete testis. From the rete testis, 15-20 effernt ductules enter the head of the epididymis. www.vision.edu.sa  Epididymis It is a highly coiled tube (6 meters) that forms a coma-shaped structure which is divided into: Head, Body & Tail. The head receives the efferent ductules and forms a cap around the upper pole of the testis. The body is the middle part and descends behind the testis. The tail opens into the vas deferens. www.vision.edu.sa  Vas Deferens A cord-like structure that begins from the tail of the epididymis and ascends behind the testis. It enters the pelvic cavity through the inguinal canal, then reaches behind the urinary bladder. The terminal part of the Vas dilates to form the ampulla The Vas then joins the duct of the seminal vesicle to form the ejaculatory duct www.vision.edu.sa  The Ejaculatory Duct It is a narrow tube that passes inside the prostate and finally opens into the prostatic urethra. The Urethra: a common pathway for urine & semen. www.vision.edu.sa The Prostate It is the largest accessory genital gland in males. It is located below the urinary bladder, surrounding the beginning of the urethra. The ducts of the gland open into the prostatic urethra. Its secretion forms 25% of the seminal fluid and contains citric acid, zinc, and enzymes. It enlarges in size with age and may compress the urethra causing retention of urine. www.vision.edu.sa  Female Genital System The female genital system consists of: Primary sex organ: Ovaries. Accessory sex organs: Two oviducts (Fallopian Tubes). Uterus. Vagina. External genitalia. Two mammary glands. www.vision.edu.sa  The Ovaries The ovary is a flattened almond-shaped small body, divided into peripheral cortex and central medulla. The cortex is broad and contains the ovarian follicles separated by the inter- follicular tissue. The medulla consists of highly vascular connective tissue, having elastic fibers, smooth muscle fibers, lymphatics and nerves. www.vision.edu.sa  The Ovarian Follicles  They are present mainly in the cortex of the ovary under the tunica albuginea. They are: Primordial follicles. Primary follicles. Secondary follicles. Mature follicles.  At birth, the average number of 1ry follicles is 4000, only 400 ova are produced during the reproductive period of the adult female. The remaining follicles degenerate and change to atretic follicles. www.vision.edu.sa  Fallopian Tubes  2 tortuos tubes, 10cm, long.  The Fallopian tube has 2 ends; one opens on the peritoneal cavity near the ovary, and the other into the uterine cavity.  It consists of 4 parts: Infundibulum, funnel-shaped & has finger-like processes “Fimbriae”. Ampulla: the longest and widest part, where fertilization occurs. Isthmus: short and narrow part. Intramural part: embedded in the uterine wall. www.vision.edu.sa  The Uterus A pear-shaped thick muscular organ which lies in the pelvis between the rectum and urinary bladder. It is formed of 4 parts: Fundus: dome-shaped part above the level of the openings of the Fallopian tubes. Body: between the fundus and isthmus. Isthmus: a constriction between the body and cervix. Cervix: narrow part having supravaginal and vaginal parts. www.vision.edu.sa The uterine cavity is triangular in shape between the openings of the uterine tubes and the internal os of the cervix. The cervical canal opens into the uterine cavity by the internal os. The lower end of the cervical canal opens into the vagina and is called external os. The wall of the uterus is formed of three layers: Perimetrium. serous outer covering. Myometrium. thick muscle layer. Endometrium. mucous lining that changes in thickness and contents with the menstrual cycle. www.vision.edu.sa  Features of umbilical cord i It is the connection between placenta and fetus. Length: 50 cm Diameter: one cm. Attachments: It is attached to fetal surface of placenta near its center, the other attachment is to ventral aspect of fetal abdominal wall. Functions: It contains umbilical vessels that connect the fetus to the placental circulation. Allows free mobility of the fetus. Constituents of the cord: 1- Mesoderm of connecting stalk that forms Wharton’s jelly. 2- Two umbilical arteries that carry non-oxygenated blood to E the placenta and one umbilical vein that carries oxygenated blood to the fetus. Umbilical vessels are formed from mesoderm around allantois. 3- Vitelline vessels formed in the mesoderm of vitello- intestinal duct. They will form blood supply of gut. 4- Vitello-intestinal duct (yolk sac stalk) that connects midgut with defenitive yolk sac. 5- Extra-embryonic part of allantois. It will degenerate. 6- Developing mid-gut enters umbilical cord from 6th to 10th week (physiological umbilical hernia). N.B. Amnion forms a sheath around these constituents.  Third week (trilaminar germ disc)  In the 3rd week, a layer of cells spread between the epiblast and E hypoblast, thus the embryonic disc becomes trilaminar.  This process is called “Gastrulation” i.e. formation of intraembryonic (2ry) mesoderm and endoderm  Development of notochord The notochord is a solid cylinder of intra-embryonic mesoderm a extending in the midline of the trilaminar embryonic disc from the primitive node to the prochordal plate. During its development it passes through several stages as follows: 1) The cranial end of the primitive streak becomes thickened to form the primitive node or Hensen's node. 2) Cells in the primitive node multiply and pass cranially in the midline between the ectoderm and endoderm. These cells form a solid cord called the notochordal process. 3) A depression appears in the center of the node. This depression is called blastopore. 4) The cavity of the blastopore extends into the notochordal process and converts it into a tube called notochordal canal. 5) The cells of the floor of the notochordal canal become intercalated (i.e. become mixed up) with the underlying endoderm. The cells in the floor of the notochordal canal now separate the canal from the cavity of the yolk sac. 6) The floor of the notochordal canal begins to break down and the whole canal communicates with the yolk sac. 7) The notochordal canal also communicates with the amniotic cavity through the blastopore. Thus at this stage the amniotic cavity and the yolk sac are in communication with each other. 8) Gradually the walls of the notochordal canal become flattened so that instead of a rounded canal we have a flat plate of cells called the notochordal plate. 9) The notochordal plate again becomes curved to assume the shape of a tube. Proliferation of cells of this tube converts it into a solid rode of cells. This rode is the definitive notochord which forms the axis of the body. 10) Soon afterwards the continuity of the endoderm is restored at the site of break down. 11) The notochord is the structure around which the vertebral column is formed. However the notochord does not give rise to the vertebral column. Most of it disappears, but parts of it persist in the region of each intervertebral disc as the nucleus pulposus. Importance of notochord: 1) Induces (stimulates) the overlying ectoderm to differentiate into neuroectoderm (neural plate). 2) Induces the formation of the vertebral bodies. 3) Forms the nucleus pulposus of each intervertebral disc.  Neurulation Notochord signals overlying ectoderm. Formation begins of spinal cord and brain (neurulation) Neural plate to neural groove to neural tube: pinched off into body. Closure of neural tube: begins at end of week 3; complete by end of week 4 (folic acid important for this step) Extends cranially (eventually brain) and caudally (spinal cord). Neural crest, lateral ectodermal cells, pulled along and form sensory nerve cells and other structures.  During the 2 nd week of development, the following events (changes) occur: 1. Completion of the implantation process. 2. 0 Differentiation of the inner cell mass into 2 layers: A. Epiblast. 3. B. as Hypoblast. Differentiation of the trophoblast into 2 layers: A. Outer layer without cell boundary (Syncytiotrophobast). B. Inner layer (Cytotrophoblast). 4. Formation of 2 cavities: A. Amniotic cavity. B. 2ry yolk sac. 5. Formation of extra-embryonic mesoderm and extra-embryonic coelom. 6. Formation of the 1ry chorionic villi. 7. Start of uteroplacental circulation. 8. Appearance of the prochordal plate.  The Decidua Definition: After implantation, the endometrium becomes the decidua which is highly vascular and highly secretory to nourish the embryo. Cause of formation: Chorionic gonadotrophic hormones secreted by the syncytiotrophoblast prolong the life of the corpus luteum in the ovary. The latter produces progesterone which maintains the decidua. Parts:  Decidua basalis: Between the embryonic pole of blastocyst and 4 the myometrium. It will form the maternal part of the placenta.  Decidua capsularis: Around the rest of the blastocyst.  Decidua parietalis: Lines the uterine cavity. The latter becomes occluded in the 3rd month by fusion of the decidua parietalis and the decidua capsularis. N.B. The cervix does not form a decidua. It is closed by a mucous plug during pregnancy.  Changes in the inner cell mass2 layers (Bi-laminar germ disc)  At the 8th day: the cells of the inner cell mass (embryoblast ) form a circular embryonic disc that becomes bilaminar i.e. is differentiated into 2 germ layers: A. Epiblast (ectoderm): A mass of tall columnar cells facing the amniotic cavity. B. Hypoblast (endoderm): A layer of cuboidal cells facing the blastocoele. At the 9th, 10th, 11th , 12th &13th days: no marked changes from the 8th dy. In the 2nd week, the embryo looks like:  A circular bilaminar disc between 2 cavities: The amnion dorsally. The yolk sac ventrally.  Cavities  2 At the 8th day:  A small cavity appears dorsal between epiblast at embryonic pole and the trophoblast : amniotic cavity.  Flat cells close to the cytotrophoblast line the amniotic cavity forming its roof amnioblasts or amniogenic epithelium. At the 9th day:  The amniotic cavity increases in size.  The blastocoele becomes progressively smaller. It becomes lined with a layer derived from the hypoblast called exocoelomic (Heuser’s) membrane.  The blastocoele is now called 1ry yolk sac. At the 10th & 11th days:  The amniotic cavity becomes larger.  The 1ry yolk sac shows no major changes. At the 13th day:  The amniotic cavity shows no major changes.  A largest part of the 1ry yolk sac is cut-off  becomes the 2ry yolk sac  Fetal Membranes They are membranes which are developed from the zygote, but don’t share in the formation of the fetus. They are: 1- Trophoblast, chorion and palcenta. 2- Amnion. l 3- Yolk sac. 4- Connecting stalk, allantois and umbilical cord. Amnioticcavity is field with Amniotic fluid The Amnion & Amniotic Cavity  Amnion is the membrane that encloses amniotic cavity. Formation of amniotic cavity: It is formed at the 8th day when amnioblasts are formed from cytotrophoblasts. Amnioblasts secret fluid which leads to formation of a small cavity between ectoderm and cyto- trophoblast known as amniotic cavity. So, floor of the cavity is ectodermal while the roof is formed from amnioblasts. By the 12th day it becomes separated from cytotrophoblasts by primary mesoderm (somatic).  Fertilization  Definition: 0  It is the fusion of the male & female gametes (union of a sperm and an ovum) to form zygote.  Normal site:  Ampulla or lateral third of the uterine (fallopian) tube. www.vision.edu.sa 1. Capacitation: process of sperm becoming fertile. – Sperms cannot fertilize oocytes when they are newly ejaculated. – It occurs in uterus and oviducts (the female genital tract). – It takes 5-7 hours. – The capacitated sperm have the ability to fertilize the egg – The acrosomal reaction cannot occur until capacitation has occurred. The glycoprotein coat and the seminal plasma protein are removed from the cell membrane covering the acrosomal cap. 2. Acrosome reaction:  Is induced by zona proteins.  Fusion occurs between the outer acrosomal membrane and the cell membrane of the corona radiata with the release of acrosomal enzymes (acrosin). 5571111 a) Hyaluronidase results in digestion of the corona radiata. b) zona lysin lead to penetration of the zona pellucida. www.vision.edu.sa  Phases of fertilization  Phase 1: penetration of corona radiata. Many sperms penetrate the corona radiata with the aid of acrosomal enzymes (hyaluronidase). During fertilization, the sperm must penetrate:  Phase 2: penetration of A-The corona radiata. zona pellucida. Only B-The zona pellucida. one sperm penetrates C. The oocyte cell membrane. the zona and once the sperm F is inside, the properties of zona pellucida will change to prevent other sperm to enter. Phase 3: fusion of the oocyte and sperm cell membranes. www.vision.edu.sa After fertilization, as soon as the sperm has entered the oocyte: a) the oocyte finishes its 2nd meiotic division & forms the female pronucleus. b) the zona pellucida becomes impermeable to other sperms. c) The head of the sperm separates from the tail, swells & forms the male pronucleus. The female pronucleus comes into close contact with male pronucleus. The nuclear membranes of the 2 pronuclei disappear and their chromosomes become around the equator thus the zygote is formed. www.vision.edu.sa  Results of Fertilization important  Restoration of the diploid number of chromosome (46).  Determination of the sex of the embryo. An X-carrying sperm produces a female embryo, and a Y- carrying sperm produces a male embryo.  Completion of the 2nd maturation (meiotic) division with formation of the 1 mature ovum and 2nd polar body.  Initiation of cleavage or cell division of the zygote.  The zona & cortical reactions occur to prevent fertilization of the same ovum by more than one sperm. www.vision.edu.sa  CLEAVAGE  Definition: – Is a series of mitotic divisions of the zygote results in an increase in cells number without increase in total size due to persistence of the zona pellucida).  Site: Uterine tube.  Stages of Cleavage  The zygote divides by mitosis into two-cell stage. Each cell is named blastomere.  Repeated mitosis giving 4 cells, 8 cells& so on until a Morula of 12-16 compacted cells is formed after 3 days (72 hours) after fertilization & enters the uterus. The morula is differentiated into an inner cell mass & an outer cell mass. www.vision.edu.sa  ISD In- Vitro Fertilization (IVF) Defination  A method of treatment of infertility, if there is occlusion of fallopian tube.  The female is given gonadotropin to stimulate multiple ovulations.  The ova are collected with aspirator during laparoscopy & are put in a glass plate.  Sperms collected from the husband are added immediately.  After fertilization, the eggs are monitored to 8- cell stage then placed in the uterus to develop to term. www.vision.edu.sa  Implantation Definition: It is the embedding of the blastocyst into the compact layer of the endometrium. Time: It begins about the 6th day after fertilization. It is completed by the 11th or 12th day. Normal site of implantation: Posterior wall of the upper part of the uterus near the fundus, in the midline. www.vision.edu.sa  The trophoblast differentiates into 2 layers: I  an inner cytotrophoblast  an outer syncytiotrophoblast (cells lose its cell boundaries) - It extends finger-like processes, which secrete proteolytic enzymes that erode the endometrium, creating a hole through which the blastocyst is gradually buried in the endometrium. - By the 9th -10th day, the hole in the endometrium is closed by a fibrin plug. The endometrium regenerates by the 12th day. www.vision.edu.sa  Abnormal Site of Implantation 1.Intra- uterine: Placenta praevia: Implantation in the lower uterine segment (cervix). 3 types: lateral, marginal and central. Cause severe bleeding before delivery. Abnormal 2. Extra-uterine: (Ectopic pregnancy): Outside the uterus:  Tubal 1 Ovarian  Abdominal. Such embryos do not come to term because the abnormal implantation site is unable to sustain the developing embryo. Furthermore, the invasive trophoblast tissue causes haemorrhage which can be life- threatening. www.vision.edu.sa  Gross Anatomy of Placenta It is the organ of exchange of materials between fetal and maternal blood. Shape: Disc like. Surfaces: -Fetal surface: It is covered with amnion and fetal blood vessels. Umbilical cord is attached near the center of this surface. -Maternal surface: Shows 15 –I 20 rounded elevations (cotyledons) with septa in between. Diameter: 15 -25 cm. Thickness: About 3 cm. Weight: About ½ kg. Site: At original implantation site which is upper part of posterior wall of uterus. Placental Circulation: -Firstly, blood vessels are formed in tertiary velli (afferent and efferent) and in connecting stalk (2 umbilical arteries and one umbilical vein). O -Placental circulation is formed of 2 components: 1- Fetal: consists of continuous blood flow through afferent andk efferent capillary loops. 2- Maternal: maternal blood fills intervillous spaces through decidual arterioles which open into the roof of the spaces. So, placental circulation is as follow: fetal blood reaches placenta through 2 umbilical arteries. Exchange of gases and nutrition. Blood returns to fetus through the umbilical vein.