Science Project Connective Animal tissues: Science Project Connective Animal tissues INDEX: INDEX Introduction On Biology Introduction On Tissues Introduction on Connective Tissue Connective Tissue Bone Connective Tissue Blood Connective Tissue Ligament Connective Tissues Tendon Connective Tissue Cartilage Connective Tissue Areolar Connective Tissue Adipose This Presentation is done by:: This Presentation is done by: Rajiv Iyer (B-25) Rahul Mukunde (B-26) Sagar Vaghela (B-27) Sakib (B-28) Shreyas Myana (B-29) An Introduction On Biology: An Introduction On Biology Biology, the science of life. The term was introduced in Germany in 1800 and popularized by the French naturalist Jean- Baptiste de Lamarck as a means of encompassing the growing number of disciplines involved with the study of living forms. The unifying concept of biology received its greatest stimulus from the English zoologist Thomas Henry Huxley, who was also an important educator. Huxley insisted that the conventional segregation of zoology and botany was intellectually meaningless and that all living things should be studied in an integrated way. Huxley’s approach to the study of biology is even more cogent today, because scientists now realize that many lower organisms are neither plants nor animals ( see Prokaryote; Protista ). The limits of the science, however, have always been difficult to determine, and as the scope of biology has shifted over the years, its subject areas have been changed and reorganized. Today biology is subdivided into hierarchies based on the molecule, the cell, the organism, and the population. PowerPoint Presentation: Molecular biology, which spans biophysics and biochemistry, has made the most fundamental contributions to modern biology. Much is now known about the structure and action of nucleic acids and protein, the key molecules of all living matter. The discovery of the mechanism of heredity was a major breakthrough in modern science. Another important advance was in understanding how molecules conduct metabolism, that is, how they process the energy needed to sustain life. Cellular biology is closely linked with molecular biology. To understand the functions of the cell—the basic structural unit of living matter—cell biologists study its components on the molecular level. Organismal biology, in turn, is related to cellular biology, because the life functions of multicellular organisms are governed by the activities and interactions of their cellular components. The study of organisms includes their growth and development (developmental biology) and how they function (physiology). Particularly important are investigations of the brain and nervous system (neurophysiology) and animal behavior ( ethology ). PowerPoint Presentation: Population biology became firmly established as a major subdivision of biological studies in the 1970s. Central to this field is evolutionary biology, in which the contributions of Charles Darwin have been fully appreciated after a long period of neglect. Population genetics, the study of gene changes in populations, and ecology, the study of populations in their natural habitats, have been established subject areas since the 1930s. These two fields were combined in the 1960s to form a rapidly developing new discipline often called, simply, population biology. Closely associated is a new development in animal-behavior studies called sociobiology, which focuses on the genetic contribution to social interactions among animal populations. Biology also includes the study of humans at the molecular, cellular, and organismal levels. If the focus of investigation is the application of biological knowledge to human health, the study is often termed biomedicine. Human populations are by convention not considered within the province of biology; instead, they are the subject of anthropology and the various social sciences. The boundaries and subdivisions of biology, however, are as fluid today as they have always been, and further shifts may be expected An Introduction On Tissues: An Introduction On Tissues Tissue, group of associated, similarly structured cells that perform specialized functions for the survival of the organism ( see Physiology). Animal tissues, to which this article is limited, take their first form when the blastula cells, arising from the fertilized ovum, differentiate into three germ layers: the ectoderm, mesoderm, and endoderm ( see Embryology: Normal Development in Animals). Through further cell differentiation, or histogenesis , groups of cells grow into more specialized units to form organs made up, usually, of several tissues of similarly performing cells. Animal tissues are classified into four main EPITHELIAL TISSUES CONNECTIVE TISSUES MUSCLE TISSUES NERVE TISSUES An Introduction on Connective Tissue: An Introduction on Connective Tissue These tissues, which support and hold parts of the body together, comprise the fibrous and elastic connective tissues, the adipose (fatty) tissues, and cartilage and bone. In contrast to epithelium, the cells of these tissues are widely separated from one another, with a large amount of intercellular substance between them. The cells of fibrous tissue, found throughout the body, connect to one another by an irregular network of strands, forming a soft, cushiony layer that also supports blood vessels, nerves, and other organs. Adipose tissue has a similar function, except that its fibroblasts also contain and store fat. Elastic tissue, found in ligaments, the trachea, and the arterial walls, stretches and contracts again with each pulse beat. In the human embryo, the fibroblast cells that originally secreted collagen for the formation of fibrous tissue later change to secrete a different form of protein called chondrion , for the formation of cartilage; some cartilage later becomes calcified by the action of osteoblasts to form bones. Blood and lymph are also often considered connective tissues. Connective Cell Tissues: Connective Cell Tissues Connective tissues include bone, cartilage, fat, ligaments, and tendons. These tissues support and connect parts of the body. The structure varies depending on the purpose of the tissue. The diagonal red band in this image shows elastin fiber, which allows connective tissue to spring back into shape following deformation. Connective Tissue Bone: Connective Tissue Bone Bone (anatomy), hard connective tissue, the major component of almost all skeletal systems in adult vertebrate animals. Bone appears to be nonliving—in fact, the word skeleton is derived from a Greek word meaning dried up. However, bone actually is a dynamic structure composed of both living tissues, such as bone cells, fat cells, and blood vessels, and nonliving materials, including water and minerals. Bones are multipurpose structures that play diverse, vital roles in vertebrates. They provide a framework for the body, supporting it and giving it shape. They also provide a surface for the attachment of muscles and act as levers, permitting many complex movements. Many bones protect softer internal organs; for example, skull bones protect the brain, and rib bones form a cage around the lungs and heart. In addition to these structural and mechanical functions, bones also participate in the body’s physiology. They store calcium, a mineral essential for the activity of nerve and muscle cells. The soft core of bone, the bone marrow, is the site of formation of red blood cells, certain white blood cells, and blood platelets PowerPoint Presentation: An adult human has 206 bones, which account for 14 percent of the body’s total weight. The longest and strongest bone is the thighbone, which at maturity is about 50 cm (20 in) long and 2.5 cm (1 in) wide. The smallest bone, the stirrup bone, is one of three tiny bones buried within the middle ear; it is only 0.18 cm (0.07 in) long. Connective Tissue Blood: Connective Tissue Blood Blood, vital fluid found in humans and other animals that provides important nourishment to all body organs and tissues and carries away waste materials. Sometimes referred to as “the river of life,” blood is pumped from the heart through a network of blood vessels collectively known as the circulatory system. An adult human has about 5 to 6 liters (1 to 2 gal) of blood, which is roughly 7 to 8 percent of total body weight. Infants and children have comparably lower volumes of blood, roughly proportionate to their smaller size. The volume of blood in an individual fluctuates. During dehydration, for example while running a marathon, blood volume decreases. Blood volume increases in circumstances such as pregnancy, when the mother’s blood needs to carry extra oxygen and nutrients to the baby. Constituents of Blood: Constituents of Blood In an average healthy person, approximately 45 percent of the blood volume is cells, among them red cells (the majority), white cells, and platelets. A clear, yellowish fluid called plasma makes up the rest of blood. Plasma, 95 percent of which is water, also contains nutrients such as glucose, fats, proteins, and the amino acids needed for protein synthesis, vitamins, and minerals. The level of salt in plasma is about equal to that of sea water. The test tube on the right has been centrifuged to separate plasma and packed cells by density. Connective Tissue Ligament: Connective Tissue Ligament Ligament, in anatomy, tough band of slightly elastic connective tissue, made of a fibrous protein known as collagen. One type of ligament, such as a collateral ligament of the elbow or knee, holds together bones and cartilage at a joint. This white, shiny ligament provides flexibility for freedom of movement and, at the same time, prevents the bones from moving too far apart. Another type of ligament is thickened tissue that surrounds and directly reinforces a joint, such as the shoulder and hip. Ligaments of yellow elastic tissue connect adjoining vertebrae in the spine. Ligaments also support abdominal organs, such as the liver, kidneys, spleen, bladder, uterus, and diaphragm, and help maintain the shape of the breasts. These ligaments are extensions of membranes covering the organs, or sheets of fibrous tissue. Persistent stress or sudden, extreme flexing of a joint can cause a ligament to be stretched too far, resulting in injury. An example of severe ligament damage is a torn anterior cruciate ligament, the major ligament connecting bones in the knee joint—a relatively common athletic injury. Ligament: Ligament Cat Claws In and Out In the normal state, the tendon attached to a cat’s claw is relaxed, allowing the claw to fall back under the skin where a ligament holds it in place. When a muscle contracts and tightens the tendon, the claw raises so that it protrudes from the paw. Connective Tissue Tendon: Connective Tissue Tendon Tendon, in anatomy, extremely strong cord that is flexible but does not stretch, made of large bundles of white, fibrous protein known as collagen. A tendon joins a muscle with a bone or another muscle. A tendon delivers the pulling force of a muscle to a bone, which makes body motion possible. A tendon attached to a bone is cylindrical while one connected to a flat muscle on the wall of the abdomen is a wide sheet of fibers. The tendons in the hands, wrists, and feet are enclosed in protective membranes and lubricated by a fluid to prevent excessive friction. A larger tendon includes a system of nerves that registers pain when the tendon is squeezed, and triggers a reflex contraction in the adjoining muscle when the tendon is stretched. The Achilles tendon, which extends from midcalf to the heel, is the thickest and strongest tendon in the human body. Rupture of this tendon is a serious injury that most commonly affects athletes participating in events involving sprinting and jumping. Rupture of a tendon in the finger can result in deformity of the hand. Connective Tissue Cartilage: Connective Tissue Cartilage Cartilage, or gristle, fibrous connective tissue found in humans and vertebrate animals that provides support to the skeleton at specific sites throughout the body. Cartilage is composed of specialized cells, called chondrocytes , surrounded by a gelatinous matrix of collagen, a tough protein. The cartilage surface is covered by a membrane known as the perichondrium . The skeleton of vertebrate fetuses is composed largely of cartilage, which is eventually replaced by bone. Some cartilage persists into adulthood. It is fibrous and rubbery, providing support, flexibility, and elasticity to the ends of bone tissue and to the nose, ears, breastbone, trachea, larynx, joints, and other parts of the body. Some animal skeletons, such as that of the shark, are completely cartilaginous. Cartilaginous Fish: Cartilaginous Fish Blue sharks exhibit a body plan typical of most sharks, with a streamlined body, pointed snout, and powerful, crescent-shaped tail fin. Aggressive hunters, blue sharks eat everything from schooling fish and squid to marine mammals. Connective Tissue Areolar: Connective Tissue Areolar Nature : It is a loose and cellular connective tissue. Its matrix consists of two kinds of fibers- White collagen fibres(which changes into gelatin on boiling in water) Yellow elastic fibres or elastin Occurrence : It is the simplest and most widely distributed connective tissue. It joins skins to muscles ,fills spaces inside the organs, is found around muscles, blood vessels and nerves. Functions : It helps in repairs of tissues. Helps in combating foreign toxins. It fixes skin to underlying muscles Connective Tissue Adipose: Connective Tissue Adipose Nature : It Is basically an aggregation of fat cells or adipocytes.Each fat cell is rounded or oval and contains a large droplet of fat that almost fills it. The aft cells are arranged into lobules separated by partitions of collagen and elastin fibres. Occurrence : The adipose tissue is abundant below the skin, between the internal organs and in yellow bone marrow. Functions : It serves as a fat reservoir. It provides shape to the limbs and body. It acts an insulator. Being a poor conductor of heat it reduces heat loss from body,i.e. it regulates body temperature. Adipose in Mice: Adipose in Mice In mice , there are eight major adipose depots, four of which are within the abdominal cavity : The paired gonadal depots are attached to the uterus and ovaries in females and the epididymis and testes in males; the paired retroperitoneal depots are found along the dorsal wall of the abdomen, surrounding the kidney, and, when massive, extend into the pelvis. The mesenteric depot forms a glue-like web that supports the intestines , and the omental depot, which originates near the stomach and spleen , and, when massive, extends into the ventral abdomen. Both the mesenteric and omental depots incorporate much lymphoid tissue as lymph nodes and milky spots , respectively. The two superficial depots are the paired inguinal depots, which are found anterior to the upper segment of the hind limbs (underneath the skin) and the subscapular depots, paired medial mixtures of brown adipose tissue adjacent to regions of white adipose tissue, which are found under the skin between the dorsal crests of the scapulae. The layer of brown adipose tissue in this depot is often covered by a “frosting” of white adipose tissue; sometimes these two types of fat (brown and white) are hard to distinguish. The inguinal depots enclose the inguinal group of lymph nodes. Minor depots include the pericardial , which surrounds the heart, and the paired popliteal depots, between the major muscles behind the knees, each containing one large lymph node . [ Of all the depots in the mouse, the gonadal depots are the largest and the most easily dissected, comprising about 30% of dissectible fat.