Transcript Tissue - scienceathawthorn

The cell is the structural and functional unit of all known living organisms. It is the
smallest unit of an organism that is classified as living, and is often called the building
brick of life.[1] Some organisms, such as most bacteria, are unicellular (consist of a single
cell). Other organisms, such as humans, are multicellular. (Humans have an estimated
100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The
largest known cell is an unfertilized ostrich
In 1835 before the final cell theory was developed, a Czech Jan Evangelista Purkyně
observed small "granules" while looking at the plant tissue through a microscope. The
cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann,
states that all organisms are composed of one or more cells. All cells come from
preexisting cells. Vital functions of an organism occur within cells, and all cells contain
the hereditary information necessary for regulating cell functions and for transmitting
information to the next generation of cells.[3]
Tissue is a cellular organizational level intermediate between cells and a complete
organism. Hence, a tissue is an ensemble of cells, not necessarily identical, but from the
same origin, that together carry out a specific function. Organs are then formed by the
functional grouping together of multiple tissues.
Connective tissues are fibrous tissues.They are comprised of cells separated by non-living
material, which is called extracellular matrix. Connective tissue holds other tissues together
such as in the formation of organs, and has the ability to stretch and contract passively.
Bone, often referred to as osseous tissue, and blood are examples of specialized connective
tissues
Muscle cells form the active contractile tissue of the body known as muscle tissue. Muscle
tissue functions to produce force and cause motion, either locomotion or movement
within internal organs. Muscle tissue is separated into three distinct categories: visceral or
smooth muscle, which is found in the inner linings of organs; skeletal muscle, in which is
found attached to bone providing for gross movement; and cardiac muscle which is found
in the heart, allowing it to contract and pump blood throughout an organism.
The growth of plant occurs only in certain specific
regions. At these s, the meristimatic tissues are
present. New cells produced by meristem are initially
those of meristem itself, but as they grow and
mature, their characteristics slowly change and they
become differentiated as components of other
tissues.
TISSUES
The heart is essential for your survival! Your heart is constantly working, even when you
are resting.
The heart, blood and blood vessels together make up the circulatory system. The heart
pumps the blood through the blood vessels to all the different tissues of the body. This
blood carries water, oxygen and nutrients. Blood is also important for removing waste
products from the body.
The heart sits between the lungs in the chest, where it is well-protected by the rib cage.
A group of related organs is an organ system. Organs
within a may be related in any number of ways, but
relationships of function are most commonly used. For
example the urinary system comprises organs that
work together to produce, store, and carry urine.
Usually there is a main tissue and sporadic tissues. The
main tissue is the one that is unique for the specific organ.
For example, main tissue in the heart is the myocardium,
while sporadic are the nerves, blood, connective etc..
Functionally related organs often cooperate to form
whole organ systems. Organs exist in all higher biological
organisms, in particular they are not restricted to animals,
but can also be identified in plants. In single-cell
organisms like bacteria, the functional analogues of
organs are called organelles.