Essentials of Medical Biochemistry (eBook)

With Clinical Cases

N. V. Bhagavan, Chung Eun Ha (Autoren)

eBook Download: PDF | EPUB

2015 | 2. Auflage
752 Seiten
Elsevier Science (Verlag)
978-0-12-416697-4 (ISBN)

Infos

Essentials of Medical Biochemistry, Second Edition: With Clinical Cases is the most condensed, yet detailed biochemistry overview available on the topic. It presents contemporary coverage of the fundamentals of biochemistry, emphasizing relevant physiologic and pathophysiologic biochemical concepts. Pivotal clinical case studies aid in understanding basic science in the context of diagnosis and treatment of human diseases, and the text illuminates key topics in molecular immunology and hemostasis. Users will find basic and fundamental concepts that will aid students and professionals in biochemistry, medicine, and other healthcare disciplines. the text is a useful refresher that will help users meet USMLE and other professional licensing examination requirements, providing thorough introductions, key points, multicolored illustrations of chemical structures and figures, fact-filled tables, and recommended reading lists. - Presents essential biochemical concepts within the context of their biological functions - Contains key clinical case studies in each chapter to enhance understanding of basic science and aid in further comprehension - Offers instructional overview figures, flowcharts, tables and multicolored illustrations - Includes integrated, recommended reading reference lists within the text - Provides an online ancillary package inclusive of PowerPoint images and more than 500 study questions to aid in comprehension and USMLE exam preparation

Chung-Eun Ha is an Associate Professor in the department of Native Hawaiian Healthat the John A. Burns School of Medicine, University of Hawaii at Manoa. Since 2001,he has been teaching medical biochemistry to students who come from disadvantagedbackgrounds. He is also actively involved in the various aspects of molecular biologyand biochemical research in the field of clinical medicine.

Textauszug

Chapter 1

The Human Organism

Organ Systems, Cells, Organelles, and Our Microbiota

Cells are the basic building blocks for all living organisms and provide support and optimal conditions for biochemical processes needed for cellular functions. This chapter mainly provides overviews of properties of living cells, cellular structures, and intracellular organelles in eukaryotic cells. Also, different types of cells and microbiota in human health and diseases are discussed.

Keywords

cell structures; cell functions; intracellular organelles; stem cells; microbiota

Key Points

1. The human organism is hierarchically organized; at the highest level, it is organized into organ systems classically related to functions and anatomical structures.

2. Distinctions among organs are the consequence of their specialized tissues and cells that are produced during embryonic differentiation, a process that begins after fertilization of an ovum by a spermatozoon and continues for some organs for a time post-partum.

3. Cells are the basic building blocks for organs and tissues in all living systems.

4. Biochemical processes within cells, and thus within organ systems, include metabolism, growth, reproduction, mutation, response, self-destruction, and evolution.

5. The body of an adult consists of more than 200 differentiated and thus specialized cell types.

6. Specialized structures with functional distinctions, organelles, exist with cells and constrain particular biological processes that create unique functions that confer metabolic efficiency and cellular integrity. Intracellular organelles work interdependently to degrade, synthesize, transport, and excrete intracellular products.

7. Cellular shape and ability to exchange substances with the circulatory and other transport systems are derived from the cellular membranes and intracellular membranous structures.

a. Mitochondria are the primary sources of energy for cells, organs, and the living animal.

b. The nucleus provides the genetic and genetic expression systems that enable growth, cell division, and cell differentiation.

8. Stem cells, a unique precursor to all cell types, tissues, and organ types, are capable of repairing damaged or defective cells, tissues, and organs.

9. The human body is colonized by microorganisms at several locations. The microbiota is primarily in the distal intestine within the gastrointestinal tract. Gastrointestinal microbes contribute to the host as both symbiotic and pathogenic agents in many physiological processes.

Organ Systems: Integrated Function at the Highest Level

The highest level of integrated functionality in humans is the organ system; these systems have been structurally recognized for thousands of years but recognized for their functional importance for only a few hundred. The 11 organ systems of humans are as follows:

• Skeletal—bones, cartilage, and ligaments. This system provides the framework and physical form for the body.

• Integumentary—skin, hair, and nails. This system provides a barrier between the outside world and the body.

• Muscular—skeletal, cardiac, and smooth muscle. This system enables movement of the body, skeleton, and internal organs.

• Digestive—mouth, stomach, small and large intestines, colon, and anus. This system provides the pathway for food ingestion and processing to extract nutrients and thus energy, and an environment in which symbiosis occurs with microorganisms that convert foodstuffs into nutrients absent from the foodstuffs but required for survival.

• Cardiovascular or circulatory—heart, arteries, veins, and lymphatic vessels. This is the transportation system by which nutrients and oxygen are exchanged with both the lungs and cells within organs.

• Respiratory—lungs with their alveolar sacs, trachea, nasal orifices, and diaphragm. This is the system for oxygen exchange with the atmosphere and specialized muscle that enables breathing.

• Excretory—kidneys and ureters, bladder, and urethra. This is the system for waste removal from nutrient utilization and organ and cell renewal as well as for maintaining electrolyte balance.

• Nervous—brain, spinal cord, nerves, and some receptors. This system provides cognition and electrical signal/information processing and transmission, and acts as the control center for the other organ systems of the human animal.

• Endocrine—glands and secretory tissues. This system provides for chemical signaling via transport using the circulatory system, a second control system.

• Reproductive—testes, ovaries, uterus, genitalia. This is the system by which the species ensures continuation of itself.

• Immune—white blood cell types, thymus, spleen. This is the system by which protection from pathogens enables survival.

Organs are composed of cells that compartmentalize the lower-level functions that are the basis for organ function in living organisms. These are, in turn, composed of organelles that further compartmentalize the biochemical reactions and processes that are highly evolved and specialized to produce the chemical substances needed to create these structures and to extract energy to drive the chemical reactions and mechanical actions which the various organ systems provide. Normal health and disease diagnosis are related to the organ systems of humans, and thus the primary sections and chapters of this biochemical text are similarly organized.

Cells: Structures and Functions

The unifying principle of biology is that all living organisms from the smallest and least complex (bacteria) to the largest (whales) and most complex (humans) are composed of cells. The precise location of cells in the multicellular organisms and the location of intracellular organelles within cells are vital in normal development and function. During injury, wound repair, or morphogenesis, the precise location and migratory patterns of cells in multicellular organisms involve several strategies, which include establishment of gradient of small molecules, regulatory networks, and genetic diversity [1]. The membrane trafficking and metabolites to correct intracellular locations are precisely regulated. Defects in the membrane trafficking lead to pathological consequences [2].

In the simplest forms of life, such as bacteria, cellular organization and biochemical functions are relatively uncomplicated and are primarily devoted to growth and reproduction. As a consequence, bacteria have evolved to survive and thrive in the widest range of environments imaginable—soil, rivers and oceans, hot springs, and frozen land, as well as in most areas of the human body. The only regions of the body that are normally sterile are the respiratory tract below the vocal chords; the sinus and middle ear; the liver and gall bladder; the urinary tract above the urethra; bones; joints; muscles; blood; the linings around the lungs; and cerebrospinal fluid. Intestinal colon contains numerous microorganisms, and they are collectively known as microbiota. Humans and microorganisms have a symbiotic relationship. A population of normal healthy microbiota is essential for the maintenance of optimal host physiology by providing nutrients and energy balance. In germ-free mice, changes in the microbial flora have ameliorated obesity. Fecal flora from healthy persons has been used to re-establish normal microbiota in a recurrent Clostridium difficile enteric infection. Diet, the quality of the gut microbiota, and genetic makeup of the host all may play a role in producing a proatherosclerotic metabolite known as trimethylamine-N-oxide (TMAO) leading to cardiovascular disease. Recent studies have revealed that dietary sources of carnitine and phosphatidylcholine (lecithin) are converted to trimethylamine by gut microbes, which in turn enter the enterohepatic blood circulation followed by its conversion to TMAO by hepatic flavin-containing monooxygenases. Colon epithelial barrier damage can provoke infection and inflammation and may lead to a spectrum of diseases. (These aspects, along with required reading references, are discussed in Chapter 11).

All bacteria belong to the super kingdom called prokaryotes. Yeasts, molds, and protozoa are also single-celled organisms, but their cellular structures and functions are more complex than those of bacteria. These organisms belong to the other super kingdom called eukaryotes, along with all higher plants and all multicellular animals. A prokaryote cell has no true nucleus or specialized organelles in the cytoplasm. Bacteria reproduce asexually by cell division (fission). Because mitochondria (discussed later) have many properties in common with bacteria, it suggests that bacteria-like organisms were assimilated into eukaryotic cells early in their evolution.

All eukaryotic cells have a well-defined nucleus surrounded by a nuclear membrane and cytoplasm containing organelles that perform specialized functions. All eukaryotic somatic cells reproduce by the complex mechanisms of mitosis and cytokinesis. Germinal cells (sperm and ova) are formed by a slightly different mechanism called meiosis.

Although the size and complexity of eukaryotic organisms differ...

Produkt-Details

• Erscheint lt. Verlag: 24.4.2015
• Sprache: englisch
• Themenwelt: Studium ► 1. Studienabschnitt (Vorklinik) ► Physiologie
• Themenwelt: Naturwissenschaften ► Biologie ► Biochemie
• Themenwelt: Naturwissenschaften ► Biologie ► Zoologie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Angewandte Physik
• Themenwelt: Technik
• ISBN-10: 0-12-416697-0 / 0124166970
• ISBN-13: 978-0-12-416697-4 / 9780124166974