...Dermis Attachment of epidermis to dermis is enhanced by an increased interface between the two tissues. The junction between the dermis and epidermis is seen in the light microscope as an uneven boundary except in the thinnest skin. Sections of skin cut perpendicular to the surface reveal numerous fingerlike connective tissue protrusions, dermal papillae, that project into the undersurface of the epidermis (see Figs. 15.1 and 15.2). The papillae are complemented by what appear to be similar epidermal protrusions, called epidermal ridges or rete ridges, that project into the der- mis. If the plane of section is parallel to the surface of the epi- dermis and passes at a level that includes the dermal papillae, however, the epidermal tissue appears as a continuous sheet of epithelium, containing circular islands of connective tissue within it. The islands are cross sections of true fingerlike der- mal papillae that project into the epidermis. At sites where in- creased mechanical stress is placed on the skin, the epidermal ridges are much deeper (the epithelium is thicker), and the dermal papillae are much longer and more closely spaced, creating a more extensive interface between the dermis and epidermis. This phenomenon is particularly well demon- strated in histologic sections that show both palmar and dor- sal surfaces of the hand, as in a section of a finger. True dermal ridges are present in thick skin in addition to dermal papillae. Dermal ridges tend to have a parallel...
Words: 1320 - Pages: 6
...Stem cells are undifferentiated biological cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells. They are found in multicellular organisms. In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues. In a developing embryo, stem cells can differentiate into all the specialized cells—ectoderm, endoderm and mesoderm (see induced pluripotent stem cells)—but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues. There are three known accessible sources of autologous adult stem cells in humans: Bone marrow, which requires extraction by harvesting, that is, drilling into bone (typically the femur or iliac crest). Adipose tissue (lipid cells), which requires extraction by liposuction. Blood, which requires extraction through apheresis, wherein blood is drawn from the donor (similar to a blood donation), and passed through a machine that extracts the stem cells and returns other portions of the blood to the donor. Stem cells can also be taken from umbilical cord blood just after birth. Of all stem cell types, autologous harvesting involves the least risk. By definition, autologous cells are obtained from one's own body, just as...
Words: 340 - Pages: 2
...differentiate into specific cell types. In reality though, the science of stem cells goes beyond these distinctions. From studying human development to creating new therapeutic alternatives for diseases, embryonic stem cell (ESC) research promises numerous benefits as it has progressed extensively in the past decade. But because of the ethical issues surrounding the destruction of human embryos, other alternatives have had to be found. So far, adult stem cells (ASCs) have been used for therapeutic purposes such as bone marrow transplants. However, donor DNA-matching has been an enduring problem with this approach. A few years ago, Shinya Yamanaka discovered induced pluripotent stem cells (iPSCs), which derives pluripotent stem cells from somatic cells, thereby overcoming both ethical and donormatching issues. Although iPSC presents much promise, the newness of this technology makes it inadequate for immediate use. Now, newer discoveries have been made. Aside from ESCs, ASCs, and iPSCs, stem cells have also been found in postnatal tissue, particularly in the umbilical cord. These umbilical cordderived stem cells have been proposed to treat illnesses ranging from Parkinsonism to leukemia in both animal models and humans alike. Above all, these stem cells face less ethical and Ronquillo 2 technical concerns than the other three methods, when it comes to research utility. Even though uncovering the secrets behind umbilical cord-derived stem cells is still in the works, this research...
Words: 3707 - Pages: 15
...Introduction Prenatal development refers to a series of development stages that begins from the fertilization of the egg by the sperm cell to the onset of birth process. It begins with the formation of the zygote to the development of the fetus. It involves three major stages namely, germinal stage, embryonic stage and fetal stage. (Balinsky, 1975) The developmental stages take place partly in the fallopian tube and in the uterus. It usually takes a period of nine month in human being but varies from one species of animal to another. There are several principles of prenatal development which basically guides the whole process. These principles are as follows. Development occurs in head to toe direction also known as cephalocaudal. That is the head develops first before the toes therefore the head and parts of the upper extremity are always more developed than the lower limb at any particular time during development. The basic forms of organs are first developed before they specialize to make functional organs. Therefore development occurs from basic form to specialized form. Development follows the order of importance. Important organs are the first to be developed followed by organs that are less important. Consequently the brain and the heart are the first organs to develop. (Carlson, 1999) The fusion of the egg and the sperm to form a single cell called zygote marks the start of the germinal period and ends after the attachment of the blastocyst to the uterine wall leading...
Words: 1670 - Pages: 7
...Define anisocytosis. varying cell sizes Define poikilocytosis varying cell shapes From which cells do B cells arise? stem cells in bone marrow From which cells do plasma cells differentiate? B cells How can a Nissl stain be used to differentiate microglia from oligodendroglia? Microglia are not discernable in a Nissl stain while oligodendroglia appear as small dark nuclei with dark chromatin In what type of CNS tissue (white or grey) are oligodendroglia predominant? white matter Into what cell type does a monocyte differentiate in tissues? Macrophages Name 2 substances produced by an eosinophil. histiminase and arylsulfatase Name the three types of leukocytic granulocytes. basophils, eosinophils, and neutrophils Name the two types of mononuclear leukocytes. lymphocytes and monocytes What are 2 functions of T cell lymphocytes? - cellular immune response regulation of B lymphocytes and macrophages What are 2 morphological features of microglia? - small irregular nuclei - and relatively little cytoplasm What are 3 examples of peripheral lymphoid tissue? - follicles of lymph nodes white pulp of spleen unencapsulated lymphoid tissue What are 3 functions of a macrophage? - pagocytosis of bacteria, cell debris, and senescent red cells - scavenges damaged cells and tissues - can function as an antigen presenting cell What are 3 morphological characteristics of monocytes? - Large - Kidney-shaped nucleus...
Words: 11777 - Pages: 48
...Jean-Marie Lux Biology 121 Stem Cell Research Paper September 12, 2012 Stem cell research is a relatively new field and has made huge advances in the past fifty years. The idea of stem cells was first made public by a Russian-American Scientist named Alexander Maksimov in 1908. However it was not until 1963 that two Canadian Scientists were able to actually demonstrate the existence of self-renewing cells found in the bone marrow of mice. The Scientists were James E. Till and Ernest A. McCulloch. So although Maksimov was the first person who put the idea of stem cells out there, it is really Till and McCulloch who are credited with proving that stems cells actually existed. Since Till and McCulloch, many Scientist have contributed to the huge advances in stem cell research. In 1968, the first successful bone marrow transplant was conducted on two siblings suffering from Severe Combined Immunodeficiency (SCID), a primary immune deficiency which typically results in the onset of one or more serious infections within the first few months of life. These infections are usually serious, and may even be life threatening. In 1978, the presence of Haematopoietic stem cells were discovered in human cord blood cells. Haematopoietic stem cells, are multipotent stem cells that give rise to all the blood cell types. In 1981, Scientist were able to derive embryonic stem cells from mice. One of the biggest advancements in all stem cell research came in 1997 when a link between...
Words: 1367 - Pages: 6
...Acquisitions Editor: Crystal Taylor Product Managers: Kelley A. Squazzo & Catherine A. Noonan Designer: Doug Smock Compositor: SPi Technologies First Edition © 2011 Lippincott Williams & Wilkins, a Wolters Kluwer business. 351 West Camden Street Baltimore, MD 21201 Printed in China All rights reserved. This book is protected by copyright. No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their official duties as U.S. government employees are not covered by the abovementioned copyright. To request permission, please contact Lippincott Williams & Wilkins at Two Commerce Square, 2001 Market street, Philadelphia, PA 19103 USA, via email at permissions@lww.com, or via website at lww.com (products and services). Library of Congress Cataloging-in-Publication Data Lambert, Harold Wayne, 1972– Lippincott’s illustrated Q&A review of anatomy and embryology / H. Wayne Lambert, Lawrence E. Wineski ; with special contributions from Jeffery P. Hogg, Pat Abramson, Bruce Palmer. — 1st ed. p. ; cm. Includes index. ISBN 978-1-60547-315-4 1. Human anatomy—Examinations, questions, etc. I. Wineski, Lawrence E. II. Title. [DNLM: 1. Anatomy—Examination Questions...
Words: 201595 - Pages: 807
...BIO 1 Paper Stem Cells Research WHAT ARE STEM CELLS? * Stem cells are biological cells found in all multicellular organisms, that can divide through mitosis and differentiate into diverse specialized cell types or can self renew to produce more stem cells. * In mammals, there are two broad types of stem cells: embryonic stem cells that are isolated from the inner cell mass of blastocysts, and adult stem cells that are found in various tissues. * In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenished in adult tissues. In a developing embryo, stem cells can differentiate into all the specialized cells, but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues. Properties The classical definition of a stem cell requires the following properties: * Self-renewal - the ability to go through numerous cycles of cell division while maintaining the undifferentiated state. * Potency - the capacity to differentiate into specialized cell types. In the strictest sense, this requires stem cells to be either totipotent or pluripotent - to be able to give rise to any mature cell type, although multipotent or unipotent progenitor cells are sometimes referred to as stem cells. In Self-Renewal.. Two mechanisms exist to ensure that the stem cell population is maintained: * Obligatory asymmetric replication - a stem cell divides into one father cell that is identical...
Words: 2510 - Pages: 11
...From cliché to inception: a review of Bioprinting Tyler Crossley MCB 404 Biomedical Ethics Dr. Pimentel Introduction The utilization of 3-dimmensional printers to produce functional applications by the personal and consumer sectors have been acknowledged since the development of this technology. Two categories for product applications of 3-dimmensional printing exist: products to improve individual personal life, such as hearing aids and prosthetic limbs; engineering parts for many consumer products, such as many components of engines, guns and even musical instruments. Whichever contextual application of this technology is desired and utilized, both ethical benefits and weaknesses exist. Multiple American companies including General Electric, Boeing, Nike, Honeywell and others have used this technology in manufacturing motor components, shoes, solar panels and other consumer products. Endless potential applications of 3-dimmensional printing exist for future developments. Interestingly, printing of meat for human consumption as an alternative to harvesting meat from animals is currently being researched. In 2008 PeTA offered a $1 million X-Prize style reward for the first group to synthetically develop such commercially viable meat. This is one case in which proposing ethical dilemmas exist, and the many alternative controversies this topic entails. Further bioethical dilemma’s and considerations exist and will be discussed...
Words: 3171 - Pages: 13
...| This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (July 2012) | In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm (Ancient Greek: διάφραγμα diáphragma "partition"), is a sheet of internal skeletal muscle[2] that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity (heart, lungs & ribs) from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.A "diaphragm" in anatomy can refer to other flat structures such as the urogenital diaphragm or pelvic diaphragm, but "the diaphragm" generally refers to the thoracic diaphragm. Other vertebrates such as amphibians and reptiles have diaphragm-like structures, but important details of the anatomy vary, such as the position of lungs in the abdominal cavity. Contents * 1 Function * 2 Anatomy * 2.1 Innervation * 2.2 Crura and central tendon * 2.3 Openings * 2.4 Comparative anatomy and evolution * 2.5 Variations * 2.6 Pathology * 3 Development * 3.1 Clinical Relevance * 4 Additional images * 5 See also * 6 References * 7 External links | FunctionThe diaphragm functions in breathing. During inhalation, the diaphragm contracts and moves in the inferior direction, thus enlarging...
Words: 4757 - Pages: 20
...body. Three different types of stem cells have been identified by scientists. Not necessarily in order of importance, they start from the embryonic group which carries the greatest potential for becoming any other cell types and as a result, the greatest subject of controversy. The other two types of stem cells are the adult stem cells, which are to a degree less useful and can only become one of a few cell types; and the induced pluripotent stem cells which are specially treated cells that can be processed to behave somewhat like embryonic stem cells. Induced pluripotent stem cells commonly abbreviated as iPS cells or iPSCs are a type of pluripotent stem cell artificially derived from a non-pluripotent cell - typically an adult somatic cell - by inducing a "forced" expression of specific genes. Stem cell research by the way happens to be one of the most important medical and scientific areas of study today. Each new discovery related to their use has indeed moved the medical community one step closer to finding treatments for many life-threatening conditions and diseases. Unique properties and applications of Embryonic stem cells Beyond a general description of stem cells, a...
Words: 2887 - Pages: 12
...Chapter 40 4 main categories of tissue: Epithelial, Connective, Muscle, Nervous. I. Epithelial Tissue (Epithelium): forms interactive surfaces with environment on external and internal body surfaces; functions as barriers. Formed from continuous sheets of tightly packed cells Covers outside of body; or lines organs and body cavities Apical surface: the free surface exposed to air or body fluids Basal surface: cells at base of epithelium are attached to a basement membrane (which is a dense layer of extracellular matrix) Is avascular (no blood vessels); the blood vessels that supply nutrients and remove wastes are in the adjacent connective tissue: diffusion Cell Shapes at APICAL surface Squamous epithelium: flat; look like floor tiles Their thinness allows rapid movement of substances through them by diffusion Cuboidal epithelium: boxlike; looks like dice Produces important secretions Columnar epithelium: tall, pillar-like; some have cilia Protects underlying tissue Functions in absorption of nutrients and secretions (digestive juices) Arrangement of Layers Simple epithelium: 1 layer of cells Stratified epithelium: 2 or more layers Protect underlying tissues where the is abrasion/ wear and tear Stratified squamous (best adapted for abrasion): covers outside of body; forms outermost layer of skin; lines mouth, esophagus, vagina, anus. Pseudostratified epithelium (false multiple layers): 1 layer of a mixture of cell shapes; looks like multiple...
Words: 6485 - Pages: 26
...Water Hydrolysis: Addition of H2O to break it apart. Dehydration: Removal of H2O to form a bond. Carbohydrates Monosaccharide: 2 common types Glucose (Hexopyranose RLRR), fructose Disaccharide: 3 common types glucose + fructose alpha glucocsidic bond = sucrose (table sugar) glucose + galactose beta galactosidic bond = lactose glucose + glucose = maltose Polysaccharide: 4 common types Starch: alpha 1,4 & 1,6 bonds btwn glucoses. amylose and amylopectin Glycogen: different branching than starch. Found in animals Cellulose: beta glucose polymer. Plant cell walls Chitin: similar to cellulose with extra nitrogen containing group. Fungus cell wall and exoskeleton Lipids Triglyceride 3 fatty acids attached to glycerol. Phospholipid One fatty acid in triglyceride replaced with a R containing phosphate group Steroids 4 carbon rings. 3 cyclohexane and 1 cyclopentane Proteins Primary structure AA sequence Secondary 3D shape resulting from hydrogen bonding btwn amino and carboxyl group. Alpha helix and beta pleated sheets Tertiary Hydrogen bonding btwn R groups Ionic bonding btwn R groups Hydrophobic and hydrophilic effects Disulfide bonds btwn Cysteine Quaternary Multiple tertiary structures come together. H-bond, disulfide bond, hydrophilic/phobic interactions Nucleic acids Polymer of what? nucleotides Parts of DNA Nitrogen base, 5 carbon sugar, phosphate group Structure 1' attached to base, 5' attached to phosphate group, 3' attached to another nucleotide, antiparallel Base types & number...
Words: 6665 - Pages: 27
...STEM CELL RESEARCH AND THERAPYAND ITS IMPACTS ON SOCIETY Abstract There are several types of stem cells being used in stem cell research and therapy today. They are embryonic, adult and induced pluripotent stem cells. Each will be discussed further. This topic has stirred much moral, ethical and political debate as whether cells from fetuses should be used in this research. This impacts governmental policies on laws and funding. Another issue that must be analyzed is the economics and who should have access to this treatment. The views of people and government on this research differ greatly across the world. There are countries that have very strict laws restricting this research while others take an extremely liberal stance. Stem Cell Research and Therapy and Its Impacts on Society Introduction Stem cells are the basic unit of life that gives rise to all living things. They are the undifferentiated cells that transform into the specialized cells that make up all of the tissues in organisms. With further research and understating, these cells can be used in medicine to cure a wide range of diseases. The most important type of stem cell to humans is the pluripotent stem cell which is usually obtained from human embryos. This has sparked controversy in many aspects of human life. In this paper, we will concentrate on animal and human stem cell research, and its impact on society. A Brief Description Of The Technology And An Explanation Of The Associated...
Words: 6987 - Pages: 28
...STEM CELL RESEARCH AND THERAPYAND ITS IMPACTS ON SOCIETY Abstract There are several types of stem cells being used in stem cell research and therapy today. They are embryonic, adult and induced pluripotent stem cells. Each will be discussed further. This topic has stirred much moral, ethical and political debate as whether cells from fetuses should be used in this research. This impacts governmental policies on laws and funding. Another issue that must be analyzed is the economics and who should have access to this treatment. The views of people and government on this research differ greatly across the world. There are countries that have very strict laws restricting this research while others take an extremely liberal stance. Stem Cell Research and Therapy and Its Impacts on Society Introduction Stem cells are the basic unit of life that gives rise to all living things. They are the undifferentiated cells that transform into the specialized cells that make up all of the tissues in organisms. With further research and understating, these cells can be used in medicine to cure a wide range of diseases. The most important type of stem cell to humans is the pluripotent stem cell which is usually obtained from human embryos. This has sparked controversy in many aspects of human life. In this paper, we will concentrate on animal and human stem cell research, and its impact on society. A Brief Description Of The Technology And An Explanation Of The Associated...
Words: 6987 - Pages: 28
