By I. Yokian. Williams Baptist College.

Objective 3 List the four principal tissue types and briefly describe the functions of each type buy discount pletal 100mg on-line. Tissues are ag- gregations of similar cells and cell products that perform specific functions cheap 100mg pletal with visa. The various types of tissues are established during Shaft of hair early embryonic development. As the embryo grows, organs form emerging from the exposed from specific arrangements of tissues. Many adult organs, includ- surface of ing the heart, brain and muscles, contain the original cells and the skin tissues that were formed prenatally, although some functional changes occur in the tissues as they are acted upon by hormones or as their effectiveness diminishes with age. It provides a foundation for understanding the microscopic structure and (b) functions of the organs discussed in the chapters that follow. In medical schools a course in times, as seen through a scanning electron microscope (SEM). Although histologists employ many different techniques has a liquid matrix, permitting this tissue to flow through vessels. Most of the histological photomi- tissue covers body surfaces, lines body cavities and ducts, and crographs in this text are at the light microscopic level. How- forms glands; (2) connective tissue binds, supports, and protects ever, where fine structural detail is needed to understand a body parts; (3) muscle tissue contracts to produce movement; and particular function, electron micrographs are used. Matrix varies in composition from one tissue to another and may Knowledge Check take the form of a liquid, semisolid, or solid. Define tissue and explain why histology is important to the study of anatomy, physiology, and medicine. Explain how the matrix permits specific kinds of cells to be even more effec- tive and functional as tissues. Histology © The McGraw−Hill Anatomy, Sixth Edition of the Body Companies, 2001 Developmental Exposition Embryoblast Blastocoele Amniotic cavity (c) Trophoblast Ectoderm Endoderm (b) Amniotic cavity (d) Ectoderm Embryonic disc Mesoderm (a) Endoderm Yolk sac Trophoblast (e) Schenk EXHIBIT 1 The early stages of embryonic development. Within 30 hours after fertilization, the zygote undergoes a The Tissues mitotic division as it moves through the uterine tube toward the uterus (see chapter 22). After several more cellular divisions, the embryonic mass consists of 16 or more cells and is called a EXPLANATION morula (mor′yoo-la˘), as shown in exhibit I.

The delivering physician should describe both the quantity and qual- ity (meconium: thickness and color) of the amniotic fluid as well as the umbilical cord buy cheap pletal 50mg online, the membranes pletal 50 mg for sale, placenta, and baby regarding meco- nium staining, loss of subcutaneous fat, and dry, sloughing skin. Operative delivery by the vaginal route must meet defined criteria, and these should be documented in the medical record (15). Multiple attempts at operative delivery, plus use of both forceps and the vacuum extractor significantly increase the risk for CNS injury to the infant (16). Delivery by planned C-section requires informed consent to include a defensible indication for the procedure. In the case of the emergency situation, the obstetrician should carry out only essential steps to effect delivery. Intrabladder catheter placement, presurgery sponge count, suction apparatus, and cautery setup all waste valuable time. All emer- gency intra-abdominal procedures mandate a postoperative abdominal film to rule out a retained sponge. There are many variables that impact the neurologic outcome for the baby, which explains why some babies born after a 30-minute time 148 Schneider delay do well, whereas others born after 15 minutes do not. The 30- minute rule of decision for C-section and incision for delivery does not ensure protection for the baby. Again, communication with the baby’s physician is essential to define to the extent possible the cause and timing of the newborn injury. Vaginal birth after prior C-section requires informed consent and the meeting of defined standards (17). Notably, ACOG states that a physician must be immediately available throughout active labor and be capable of monitoring labor and performing an emergency Cesar- ean delivery.

Physiology of the Hagenbuch B proven pletal 50 mg, Stieger B order pletal 100 mg visa, Foguet M, Lub- Raven, 1987;817–851. The liver synthesizes glucose from noncarbohydrate cells), Kupffer cells, and fat storage cells (also called stel- sources, a process called gluconeogenesis. The liver is the first organ to experience and respond to tions and defend the liver. The liver is one of the main organs involved in fatty acid glucose levels and in metabolizing drugs and toxic sub- synthesis. The liver modifies the action of hormones released by quate supply of nutrients for metabolism. The hepatic portal vein car- ries the absorbed nutrients from the GI tract to the liver, The Arrangement of Hepatocytes Along Liver which takes up, stores, and distributes nutrients and vita- Sinusoids Aids the Rapid Exchange of Molecules mins. It also regulates the circulating blood lipids Hepatocytes are highly specialized cells. The bile canalicu- by the amount of very low density lipoproteins (VLDLs) it lus is usually lined by two hepatocytes and is separated secretes. Many of the circulating plasma proteins are syn- from the pericellular space by tight junctions, which are im- thesized by the liver. In addition, the liver takes up numer- permeable and, thus, prevent the mixing of contents be- ous toxic compounds and drugs from the portal circulation. The liver also serves as an excretory organ series of ducts, and it may eventually join the pancreatic for bile pigments, cholesterol, and drugs. The pericellular space, the space between two hepato- THE ANATOMY OF THE LIVER cytes, is continuous with the perisinusoidal space (see Fig. The perisinusoidal space, also known as the space of gans and systems of the body. It interacts with the cardio- Disse, is separated from the sinusoid by a layer of sinu- vascular and immune systems, it secretes important sub- soidal endothelial cells.