After fertilization, the zygote gives rise many cells to form the embryo. The first embryonic cells generated have the ability to differentiate into any type of cell in the body and, as such, are called omnipotent , meaning each has the capacity to divide, differentiate, and develop into a new organism.
As cell proliferation progresses, three major cell lines are established within the embryo. Each of these lines of embryonic cells forms the distinct germ layers from which all the tissues and organs of the human body eventually form. Figure 4. Note that epithelial tissue originates in all three layers, whereas nervous tissue derives primarily from the ectoderm and muscle tissue derives from the mesoderm.
View this slideshow to learn more about stem cells. How do somatic stem cells differ from embryonic stem cells? A tissue membrane is a thin layer or sheet of cells that either covers the outside of the body e.
Two basic types of tissue membranes are recognized based on the primary tissue type composing each: connective tissue membranes and epithelial membranes Figure 4.
A connective tissue membrane is built entirely of connective tissue. This type of membrane may be found encapsulating an organ, such as the kidney, or lining the cavity of a freely movable joint e. When lining a joint, this membrane is referred to as a synovial membrane. Cells in the inner layer of the synovial membrane release synovial fluid, a natural lubricant that enables the bones of a joint to move freely against one another with reduced friction. An epithelial membrane is composed of an epithelial layer attached to a layer of connective tissue.
A mucous membrane, sometimes called a mucosa, lines a body cavity or hollow passageway that is open to the external environment. This type of membrane can be found lining portions of the digestive, respiratory, excretory, and reproductive tracts. Mucus, produced by uniglandular cells and glandular tissue, coats the epithelial layer. A serous membrane lines the cavities of the body that do not open to the external environment. Serous fluid secreted by the cells of the epithelium lubricates the membrane and reduces abrasion and friction between organs.
Serous membranes are identified according to location. Three serous membranes are found lining the thoracic cavity; two membranes that cover the lungs pleura and one membrane that covers the heart pericardium. A fourth serous membrane, the peritoneum, lines the peritoneal cavity, covering the abdominal organs and forming double sheets of mesenteries that suspend many of the digestive organs.
A cutaneous membrane is a multi-layered membrane composed of epithelial and connective tissues. The apical surface of this membrane exposed to the external environment and is covered with dead, keratinized cells that help protect the body from desiccation and pathogens. Parenchyma stores proteins, starch, and oils in the plant. They also contribute to the growth, development, and support of the plant. The collenchyma cells are similar to parenchymal cells in having a primary cell wall. The cell wall materials are deposited in the edges of the cell forming collenchyma.
Collenchyma cells contribute to the elongation of plant stems. However, they only provide support when the plant is turgid because their cell walls lack hydrophilic substances. The sclerenchyma cells have thick walls containing lignin. This structure makes sclerenchyma waterproof and strong. The sclerenchyma provides support to the plant more than parenchyma and collenchyma.
However, it is more difficult to make thus it is not as abundant as other types of ground tissue. Owing to their rigidity, sclerenchyma may be incorporated in the structure of vessel tissues, it forms the tracheids and vessels in the xylem. The vascular tissues of the plant represent the main system responsible for transportation in the plant, it is composed of xylem and phloem.
Vascular tissue is present in all parts of the plant in the form of vascular bundles, stems, leaves, and traversing roots. The xylem transports different materials such as water and ions from roots to leaves and stems of the plant.
The phloem transports metabolites, such as amino acids, sugars, and ions produced by the plant from the site of production in leaves to different areas like roots, fruits, and leaves. The phloem is mainly made up of companion cells , phloem parenchyma cells , sieve tubes, and phloem fibers.
Sieve plates separate sieve tubes, these tubes have pores termed as sieve pores. Even though sieve elements lack nuclei, they are living cells containing plasmalemma and proteins. Companion cells surround sieve elements. They contain large nuclei, vacuoles, and dense cytoplasm. Companion cells function to transport metabolites in and out of sieve elements. The xylem consists of xylem vessels, tracheids, xylem parenchymal cells, and xylem fibers. Large plates join vessels together leaving gaps between vessels, while the ends of tracheids overlap with the following cells with no gaps in between.
Lignin is distributed in different forms in vessels such as helical, reticulate, annular, scalariform, and pitted. It can be transported either longitudinally or laterally through pores or pits of plates. Tissue engineering is a method of producing tissues outside the body, it combines biological and engineering to repair or create new tissues. This science can affect the medical field greatly by enhancing recovery of damaged tissues due to burns, trauma, or diseases by creating an artificial graft of tissues.
Even though this approach seems promising, however, it faces some difficulties such as creating artificial nutritional blood vessels and supplying tissues with circulating blood. Other challenges include manufacturing and using bioreactors to create tissues using the exact right amount of nutrients, enzymes, and cellular components.
Cell differentiation in culture might not be controlled so the produced tissue will be hypertrophied and may contain more than one nucleus per cell leading to the formation of a deformed tissue.
Therefore, tissue engineering is an emerging promising science that implies the importance and impact of tissue culturing in the field of medicine. Try to answer the quiz below to check what you have learned so far about tissues. Plant organs are comprised of tissues working together for a common function. The different types of plant tissues are meristematic, simple, secretory, and complex tissues. Find out the distinctive characteristics of each tissue in terms of structure and function Read More.
Stems primarily provide plants structural support. This tutorial includes lectures on the external form of a woody twig and the origin and development of stems. Also included are the different modified stems that carry out special functions. Leaves are the major photosynthetic organ of a plant. Apart from that, they are also crucial to water movement. In this tutorial, various plant processes are considered in more detail. It also includes topics on leaf arrangements, leaf types, leaf structure, leaf color, abscission, and importance to humans The human respiratory system is an efficient system of inspiring and expiring respiratory gases.
This tutorial provides details of the different parts and functions of the respiratory system The circulatory system is key to the transport of vital biomolecules and nutrients throughout the body. Learn about the different components and functions of the human circulatory system dealt with in detail in this tutorial.
The lymphatic system is also elucidated elaborately here The human body is capable of regulating growth and energy balance through various feedback mechanisms.
Get to know the events of absorptive and post-absorptive states. This tutorial also describes the endocrine and neural control of compounds such as insulin and glucagon. It also deals with the regulation of growth, heat loss, and heat gain.
The consequences of antibiotic use in horticulture. Nervous System. The interstitium — a new biological organ? Types of Transplants. Skip to content Main Navigation Search. Dictionary Articles Tutorials Biology Forum. Table of Contents. Biology definition: A tissue is an aggregate of cells in an organism that have similar structure and function.
Tissues that work in unison to carry out a specific set of functions form an organ. Examples of plant tissues are meristematic tissues and vascular tissues. Examples of animal tissues are epithelial tissues, connective tissues, muscular tissues, and nervous tissues. Etymology: Middle English tissu, a rich kind of cloth, from Old French, from past participle of tistre, to weave, from Latin texere.
The fundamental types of tissues in animals are as follows: Epithelial tissues or epithelium Connective tissues Muscle tissues Nervous tissues. In plants , the different types of tissues are: 1 Embryonic or meristematic tissues e. What is a tissue? Aggregate of cells that function together for a particular function. Aggregate of cells that function differently from and independent of one another. Solitary cell that carries out a specific function. Animal tissue that covers the whole surface of the body Connective tissue.
Muscular tissue. Epithelial tissue. The tissue where blood belongs Connective tissue. Muscle tissue that is striated and involuntary Skeletal muscle. Smooth muscle. Cardiac muscle. Plant tissue made up of cells that have thin walls and primarily store proteins, starch, and oils Xylem.
Send Your Results Optional. Your Name. To Email. Time is Up! Plant Tissues Plant organs are comprised of tissues working together for a common function. Stems Stems primarily provide plants structural support. Skip to main content. Organization at the Tissue Level.
Search for:. Introduction to Tissues. Tissues in Levels of Organization The human body is organized at several levels of scale that can each be examined. Learning Objectives Characterize where tissues fall in levels of organization. Key Takeaways Key Points The human body has many levels of structural organization: atoms, cells, tissues, organs, and organ system.
Many organs working together to accomplish a common purpose is called an organ system. Licenses and Attributions. CC licensed content, Shared previously.
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