Cephalexin

Ovulation occurs as the result of a positive feedback of fol- terone buy cheap cephalexin 750 mg line antibiotics long term effects, such that estradiol induces proliferation of the uter- licular estradiol on the hypothalamic-pituitary axis that in- ine endometrium order cephalexin 250 mg with mastercard antibiotic resistance gene in plasmid, whereas progesterone induces differen- duces LH and FSH surges. Follicular development occurs in distinct steps: primordial, distinct products. Follicular rupture (ovulation) requires the coordination of creasing quantities of GnRH, which increases LH and FSH appropriately timed LH and FSH surges that induce in- secretion, enhances ovarian function, and leads to the first flammatory reactions in the graafian follicle, leading to ovulation. Follicular atresia results from the withdrawal of go- ment and estradiol secretion. The tive-feedback effects on the hypothalamus and on pituitary Trelease from the ovary of a mature female germ cell or gonadotrophs, generating the cyclic pattern of LH and ovum occurs at a distinct phase of the menstrual cycle. The FSH release characteristic of the female reproductive sys- secretion of ovarian steroid hormones, estradiol and prog- tem. Since the hormonal events during the menstrual cycle esterone, and the subsequent release of an ovum during the are delicately synchronized, the menstrual cycle can be menstrual cycle are controlled by cyclic changes in LH and readily affected by stress and by environmental, psycho- FSH from the pituitary gland, and estradiol and proges- logical, and social factors. The cyclic changes in steroid hor- The female cycle is characterized by monthly bleeding, mone secretion cause significant changes in the structure resulting from the withdrawal of ovarian steroid hormone and function of the uterus in preparing it for the reception support of the uterus, which causes shedding of the super- of a fertilized ovum. At different stages of the menstrual cy- ficial layers of the uterine lining at the end of each cycle. Menstrual 667 668 PART X REPRODUCTIVE PHYSIOLOGY cycles are interrupted during pregnancy and lactation and lation. Menstruation signifies a failure to con- and androgen and estradiol secretion, and LH regulates the ceive and results from regression of the corpus luteum and secretion of progesterone from the corpus luteum. Ovarian subsequent withdrawal of luteal steroid support of the su- steroids inhibit the secretion of LH and FSH with one ex- perficial endometrial layer of the uterus. Activin (an inhibin-binding protein) increases the se- An overview of the interactions of hormonal factors in fe- cretion of FSH, and follistatin (an activin-binding protein) male reproduction is shown in Figure 38. The placenta produces leasing hormone (GnRH), which controls the secretion of several pituitary-like and ovarian steroid-like hormones. The The mature ovary has two major functions: the matura- mammary glands are also under the control of pituitary tion of germ cells and steroidogenesis. Each germ cell is ul- hormones and ovarian steroids, and provide the baby with timately enclosed within a follicle, a major source of steroid immunological protection and nutritional support through hormones during the menstrual cycle. Lactation is hormonally controlled by prolactin ovum or egg is released and the ruptured follicle is trans- (PRL) from the anterior pituitary, which regulates milk formed into a corpus luteum, which secretes progesterone production, and oxytocin from the posterior pituitary, as its main product. FSH is primarily involved in stimulat- which induces milk ejection from the breasts. GnRH, a decapeptide pro- duced in the hypothalamus and released in a pulsatile man- Brain ner, controls the secretion of LH and FSH through a portal Centers vascular system (see Chapter 32). Blockade of the portal system reduces the secretion of LH and FSH and leads to ovarian atrophy and a reduction in ovarian hormone secre- Hypothalamus tion. The secretion of GnRH by the hypothalamus is regu- lated by neurons from other brain regions. Neurotransmit- ters, such as epinephrine and norepinephrine, stimulate the GnRH Dopamine secretion of GnRH, whereas dopamine and serotonin in- hibit secretion of GnRH. In addition, ovarian steroids and peptides and hypothalamic neuropeptides can regulate the Anterior pituitary secretion of GnRH. GnRH binds to high- affinity receptors on the gonadotrophs and stimulates the FSH/LH PRL secretion of LH and FSH through a phosphoinositide-pro- tein kinase C-mediated pathway (see Chapter 1). Inhibin , activin , A graph of LH release throughout the female life span is Ovary follistatin shown in Figure 38. During the neonatal period, LH is re- leased at low and steady rates without pulsatility; this pe- riod coincides with lack of development of mature ovarian Estradiol, follicles and very low to no ovarian estradiol secretion. Pul- progesterone, androgen satile release begins with the onset of puberty and for sev- eral years is expressed only during sleep; this period coin- cides with increased but asynchronous follicular Reproductive Secondary sex development and with increased secretion of ovarian estra- tract characteristics diol. Upon the establishment of regular functional men- Regulation of the reproductive tract in the strual cycles associated with regular ovulation, LH pulsatil- FIGURE 38. The main reproductive hormones are ity prevails throughout the 24-hour period, changing in a shown in boxes. Positive and negative regulations are depicted by monthly cyclic manner. The ovaries are in the pelvic portion of the abdominal cav- ity on both sides of the uterus and are anchored by ligaments THE FEMALE REPRODUCTIVE ORGANS (Fig. An adult ovary weighs 8 to 12 g and consists of an outer cortex and an inner medulla, without a sharp demarca- The female reproductive tract has two major components: tion.

In pigeon breast (pectus results in a simple fracture purchase 250mg cephalexin with mastercard antibiotic resistant virus, which is not usually serious cheap cephalexin 500mg line bacteria cell. If the carinatum), the sternum is pushed forward and downward like the nasal septum or cribriform plate of the ethmoid bone is fractured, keel of a boat. In funnel chest (pectus excavatum), the sternum is however, careful treatment is required. If the cribriform plate is pushed posteriorly, causing an anterior concavity in the thorax. The absence of ribs is due to incomplete development of the Whiplash is a common injury to the neck due to a sudden thoracic vertebrae, a condition termed hemivertebrae, and may and forceful displacement of the head (see fig. A whiplash is usually extremely painful rib is attached to the transverse process of the seventh cervical and difficult to treat because of the difficulty in diagnosing the vertebra, and it either has a free anterior portion or is attached to extent of the injury. Pressure of a cervical rib on the brachial The sensory organs within the head are also very prone to plexus may produce a burning, prickling sensation (paresthesia) trauma. The eyes may be injured by sudden bright light, and loud along the ulnar border of the forearm and atrophy of the medial noise can rupture the tympanic membrane of the middle ear. Diseases of the Head and Neck The rapid and complex development of the heart and The head and neck are extremely susceptible to infection, espe- major thoracic vessels accounts for the numerous congenital cially along the mucous membranes lining body openings. Cardiac malformations usually arise from developmen- The cutaneous area of the head most susceptible to infec- tal defects in the heart valves, septa (atrial and/or ventricular), tions extends from the upper lip to the midportion of the scalp. The infection may even spread into the sagittal ve- blood in the left atrium. A ventricular septal defect usually oc- nous sinus, causing venous sinus thrombosis. A boil in the facial curs in the upper portion of the interventricular septum and is region may secondarily cause thrombosis of the facial vein or the generally more serious than an atrial septal defect because of spread of the infection to the sinuses of the skull. Before antibi- the greater fluid pressures in the ventricles and the greater otics, such sinus infections had a mortality rate of 90%. Surface and Regional © The McGraw−Hill Anatomy, Sixth Edition Anatomy Companies, 2001 Chapter 10 Surface and Regional Anatomy 335 Congenital valvular problems are classified as either an in- cian as reference locations for palpation (feeling with firm pres- competence (leakage) or a stenosis (constriction) of valves. Im- sure, percussion tapping with the fingertips), and auscultation (lis- proper closure of a valve permits some backflow of blood, causing tening with a stethoscope). As mentioned earlier, many of the an abnormal sound referred to as a murmur. Murmurs are com- ribs are evident on a thin person, and all but the first, and at mon and generally have no adverse affect on a person’s health. The sternum, clavicles, and The tetralogy of Fallot is a combination of four defects scapulae also provide important bony landmarks in conducting a within the heart of a newborn: (1) a ventricular septal defect, physical examination. The nipples in the male and prepubescent (2) an overriding aorta,(3) pulmonary stenosis,and (4) right female are located at the fourth intercostal spaces. It immediately causes a cyanotic con- of the left nipple in males provides a guide for where to listen for dition (blue baby). The breasts and mam- casionally results in both a left and a right aortic arch. In this mary glands are highly susceptible to infections, cysts, and tu- case, there are generally anomalies of other vessels as well. The superficial position of the breasts allows for effective treatment by way of surgery and radiotherapy if tumors are de- Trauma to the Thorax tected early. The importance of breast self-examination (BSE) (see chapter 21) cannot be overemphasized. Breast cancer, or carci- Because of its resilience, the rib cage generally provides consider- noma of the breast, is surpassed only by lung cancer as the most able protection for the thoracic viscera. One in nine women will develop breast cancer, adults, are frequently fractured by direct trauma or, indirectly, by and one-third of these will die from the disease. Ribs 3 through 8 are the ones most commonly The lungs can be examined through percussion,ausculta- fractured. The first and second ribs are somewhat protected by tion,or observation.

The muscularis is the middle layer 250mg cephalexin visa virus killer, composed of a thick the urinary bladder purchase 750mg cephalexin otc bacteria 68. Although the shape and position of the inner circular layer of smooth muscle and a thin outer longitudi- uterus changes dramatically during pregnancy (fig. Peristaltic contractions of the muscu- its nonpregnant state it is about 7 cm (2. The anatomical regions of the uterus include the uterine tube is part of the visceral peritoneum. It is a Greek word meaning “trumpet” or “tube,” and is larged main portion, called the body of the uterus; and the the root of such clinical terms as salpingitis (sal'pin-ji'tis) or inflam- inferior constricted portion opening into the vagina, called mation of the uterine tubes; salpingography (radiography of the uter- the cervix of the uterus (fig. The cervix projects pos- ine tubes); and salpingolysis (the breaking up of adhesions of the uterine tube to correct female infertility). The oocyte takes 4 to 5 days to move through the uterine The uterine cavity is the space within the fundus and body tube. If enough viable sperm are ejaculated into the vagina dur- regions of the uterus. The narrow cervical canal extends through ing coitus, and if there is an oocyte in the uterine tube, fertiliza- the cervix and opens into the lumen of the vagina (fig. The The junction of the uterine cavity with the cervical canal is zygote will move toward the uterus where implantation occurs. If called the isthmus of uterus, and the opening of the cervical the developing embryo (called a blastocyst) implants into the canal into the vagina is called the uterine ostium. Female Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 Chapter 21 Female Reproductive System 735 Cervix of uterus FIGURE 21. The round ligaments are ac- tually continuations of the ovarian ligaments that support the ovaries. Each round ligament extends from the lateral border of the uterus just below the point where the uterine tube attaches to the lateral pelvic wall. Similar to the course taken by the duc- tus deferens in the male, each round ligament continues through FIGURE 21. Although the uterus has extensive support, considerable movement is possible. The uterus tilts slightly posteriorly as Support of the Uterus the urinary bladder fills, and it moves anteriorly during defecation. In some women, the uterus may become displaced and interfere with The uterus is maintained in position by the muscles of the pelvic the normal progress of pregnancy. A posterior tilting of the uterus is floor and by ligaments that extend to it from the pelvic girdle or called retroflexion, whereas an anterior tilting is called anteflexion. The ligaments that support the uterus undergo marked hypertrophy during pregnancy and regress in size follow- The wall of the uterus is composed of three layers: the ing parturition. They atrophy after menopause, which may con- perimetrium, myometrium, and endometrium (fig. The tribute to a condition called uterine prolapse, or downward perimetrium, the outermost serosal layer, consists of the thin vis- displacement of the uterus. The lateral portion of the perimetrium is con- Four paired ligaments support the uterus in position within tinuous with the broad ligament. The ovaries and uterine rectouterine pouch (pouch of Douglas) is formed as the peri- tubes are also supported by the broad ligaments. The cardinal (lateral cervical) ligaments (not illus- trated) are fibrous bands within the broad ligament that extend laterally from the cervix and vagina across the pelvic floor, perimetrium: Gk. Female Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 736 Unit 7 Reproduction and Development Uterine tube Aorta Ovarian artery Uterine artery Ovarian artery Ovary Common iliac artery Internal iliac artery Vaginal artery Uterine artery FIGURE 21. The thick myometrium is composed of three thick poorly The uterus has both sympathetic and parasympathetic in- defined layers of smooth muscle, arranged in longitudinal, circu- nervation from the pelvic and hypogastric plexuses. The myometrium is thickest in the fun- nomic innervations serve the arteries of the uterus,whereas the dus and thinnest in the cervix. During parturition, the muscles of smooth muscle of the myometrium receives only sympathetic this layer are stimulated to contract forcefully. The endometrium, the inner mucosal lining of the uterus, is composed of two distinct layers. The vagina The extent to which the uterus enlarges during pregnancy is is about 9 cm (3.

They synapse in part in the adjacent nuclei of the trapezoid B body generic 250mg cephalexin overnight delivery infection z trailer, namely buy cephalexin 500 mg otc infection minecraft server, the anterior nucleus of the trapezoid body (A18) and the posterior nu- cleus of the trapezoid body (superior olive) (AB19). The spinal tract of the trigeminal nerve (A20) lies in the lateral field. Pons, Cross Sections 111 11 10 9 7 12 8 5 4 1 13 3 16 2 20 6 14 19 15 18 22 5 4 3 1 11 9 8 23 29 6 2 10 20 21 19 16 24 18 15 21 A Cross section through the pons at 30 24 the level of the genu of the facial nerve (VII) 28 11 12 13 26 27 25 17 19 15 28 V 29 12 26 27 11 13 19 25 17 15 B Cross section through the pons at 30 the level of the trigeminal nerve 24 (V) Kahle, Color Atlas of Human Anatomy, Vol. Itsnucleus,thespinal Its nucleus, the nucleus of the hypoglossal nucleus of the accessory nerve (C14), nerve (B1), forms a column of large multi- forms a narrow cell column from C1 to C5 or polar neurons in the floor of the rhomboid C6. The large multipolar neurons lie at the fossa (trigon of hypoglossal nerve). The cells of a number of cell groups, each of which in- of the caudal section supply the trapezius nervates a particular muscle of the tongue. The and olive and form two bundles that then nerve fibers emerge from the lateral aspect combine into a nerve trunk. It forms a loop, the arch of the bundles from the caudal part of the ambigu- hypoglossal nerve (A3), and reaches the root ous nucleus join the nerve here as cranial of the tongue slightly above the hyoid bone roots (C16). Both components pass through between the hypoglossal muscle and the my- the jugular foramen (C17). Immediately lohyoid muscle, where it ramifies into termi- after passing, the fibers change from the nal branches. It passes through the combining with the inferior root (A5) (sec- sternocleidomastoid muscle and reaches ond and third cervical nerve). The cervical the trapezius muscle with its terminal fibers for the geniohyoid muscle (A6) and the branches. The hypoglossal Clinical Note: Injury to the accessory nerve nerve gives off the lingual branches to the causes the head to tilt (plagiocephaly). The arm hypoglossal muscle (A8), the genioglossal can no longer be lifted above the horizontal. Clinical Note: Injury to the hypoglossal nerve causes hemilateral shrinkage of the tongue (hemi- atrophy). When the tongue is stuck out, it turns to the affected side because the genioglossal muscle, which moves the tongue to the front, dominates on the healthy side. Eleventh and Twelfth Cranial Nerves 113 C1 1 9 11 C2 10 3 C3 1 8 4 5 6 7 2 A Muscles supplied by the hypoglossal nerve B Nuclear region and exit of the hypoglossal nerve 17 16 15 18 19 20 14 12 13 D Muscles supplied by the accessory nerve C Nuclear region and exit of the accessory nerve Kahle, Color Atlas of Human Anatomy, Vol. The tenth cranial nerve not only supplies areas in the head region like the other cranial nerves, it also descends into thorax Head Region (B–D) and abdomen where it ramifies in the In addition to a meningeal branch (sensory viscera like a plexus. It is the strongest para- supply to the dura mater in the posterior sympathetic nerve of the autonomic nervous cranial fossa), the vagus nerve gives off the system and, hence, the most important antag- auricular branch (B15). The latter branches onist of the sympathetic nervous system off at the superior ganglion, passes through (p. Motor fibers (branchial arch muscles) the dorsal and caudal region (D) and a small! Taste fibers Cervical Region (B, E, F) The fibers emerge directly from behind the olive, unite to form the nerve trunk, and Inside a common connective-tissue sheath, leave the skull through the jugular foramen the nerve descends in the neck together (B1). In the foramen, the nerve forms the su- with the internal carotid artery, the com- periorganglionofthevagusnerve (jugular gan- mon carotid artery, and the internal jugular glion) (B2) and, after passing through it, the vein; it emerges with them through the much larger inferior ganglion of the vagus upper thoracic aperture. It gives off four branches: The motor fibers for the branchial arch 1 The pharyngeal branches (B16) at the muscles (AB4) originate from large multi- level of the inferior ganglion. They com- polar neurons in the ambiguous nucleus bine in the pharynx with fibers of the (AB5). At the outer surface of the vagus nerve (AB7), which lies laterally to muscles and in the submucosa of the the nucleus of the hypoglossal nerve in the pharynx, the latter forms a meshwork of floor of the rhomboid fossa. The vagal fibers provide sensory innervation The exteroceptive sensory fibers (AB8) origi- to the muscosa of the trachea and mu- nate from neurons in the superior ganglion. The taste buds (E) on the root (B9) and terminate in the spinal nu- epiglottis are also supplied by the vagus cleus of the trigeminal nerve (AB10). The fibers run as part of the solitary tract (B12) in caudal direction and terminate at various levels of the solitary nucleus (AB13).