Cell Structure and Function
Before you begin to study the different structures and functions of the human body familiar examples of which are hydrogen, oxygen, carbon, nitrogen, calcium. Thus a structure (algebra) for this signature consists of a set of elements A together with two binary functions, that can be enhanced with a unary function, . signature for set theory includes a single binary relation ∈. In the other question, I am asking for an example to show that a relation underlying a choice structure should not necessarily be a rational relation. The only.
Epithelial cells are polarized, meaning that they have a top and a bottom side.
Tissues, organs, & organ systems (article) | Khan Academy
The apical, top, side of an epithelial cell faces the inside of a cavity or the outside of a structure and is usually exposed to fluid or air. The basal, bottom, side faces the underlying cells. For instance, the apical sides of intestinal cells have finger-like structures that increase surface area for absorbing nutrients. Image showing three cells lining the small intestine. Each cell contains a nucleus and is surrounded by a plasma membrane. The tops of the cells have microvilli that face the cavity from which substances will be absorbed.
Often, the cells are joined by specialized junctions that hold them tightly together to reduce leaks. Connective tissue Connective tissue consists of cells suspended in an extracellular matrix. In most cases, the matrix is made up of protein fibers like collagen and fibrin in a solid, liquid, or jellylike ground substance. Connective tissue supports and, as the name suggests, connects other tissues. Loose connective tissue, show below, is the most common type of connective tissue.
It's found throughout your body, and it supports organs and blood vessels and links epithelial tissues to the muscles underneath. Dense, or fibrous, connective tissue is found in tendons and ligaments, which connect muscles to bones and bones to each other, respectively. Loose connective tissue is composed of loosely woven collagen and elastic fibers.
The fibers and other components of the connective tissue matrix are secreted by fibroblasts. Specialized forms of connective tissue include adipose tissue—body fat—bone, cartilage, and bloodin which the extracellular matrix is a liquid called plasma. Muscle tissue Muscle tissue is essential for keeping the body upright, allowing it to move, and even pumping blood and pushing food through the digestive tract.
Muscle cells, often called muscle fibers, contain the proteins actin and myosin, which allow them to contract. There are three main types of muscle: From left to right. Smooth muscle cells, skeletal muscle cells, and cardiac muscle cells. Smooth muscle cells do not have striations, while skeletal muscle cells do. Cardiac muscle cells have striations, but, unlike the multinucleate skeletal cells, they have only one nucleus. Cardiac muscle tissue also has intercalated discs, specialized regions running along the plasma membrane that join adjacent cardiac muscle cells and assist in passing an electrical impulse from cell to cell.
Skeletal muscle is attached to bones by tendons, and it allows you to consciously control your movements. For instance, the quads in your legs or biceps in your arms are skeletal muscle.
Cardiac muscle is found only in the walls of the heart. Like skeletal muscle, cardiac muscle is striated, or striped. But it's not under voluntary control, so—thankfully! The individual fibers are connected by structures called intercalated disks, which allow them to contract in sync.
Smooth muscle is found in the walls of blood vessels, as well as in the walls of the digestive tract, the uterus, the urinary bladder, and various other internal structures.
Smooth muscle is not striped, striated, and it's involuntary, not under conscious control. That means you don't have to think about moving food through your digestive tract!
Nervous tissue Nervous tissue is involved in sensing stimuli—external or internal cues—and processing and transmitting information. It consists of two main types of cells: The neurons are the basic functional unit of the nervous system.
They generate electrical signals called conducted nerve impulses or action potentials that allow the neurons to convey information very rapidly across long distances. The glia mainly act to support neuronal function. The neuron has projections called dendrites that receive signals and projections called axons that send signals.C Programming Tutorial - 69: Passing Structures to Functions
Also shown are two types of glial cells: For example, the heart pumps blood, the lungs bring in oxygen and eliminate carbon dioxide, and the skin provides a barrier to protect internal structures from the external environment. Most organs contain all four tissue types.
The layered walls of the small intestine provide a good example of how tissues form an organ. The inside of the intestine is lined by epithelial cells, some of which secrete hormones or digestive enzymes and others of which absorb nutrients. Around the epithelial layer are layers of connective tissue and smooth muscle, interspersed with glands, blood vessels, and neurons.
The smooth muscle contracts to move food through the gut, under control of its associated networks of neurons. From outside to inside: Blood vessels, networks of nerves in smooth muscle layers, connective tissue, more smooth muscle, another layer of connective tissue, epithelial tissue, and empty space in the middle as the path of digested food. Plant and animal cells are eukaryotes. Plant cells are generally a square shape while animal cells are usually circular.
Plant cells and animal cells have evolved different organelles to perform specific functions. Plant cells have chloroplasts, a cell wall and a central vacuole.
Structure (mathematical logic)
Animal cells lack these three organelles. Plant cells have chloroplasts because they make their own food. Plant cells have a cell wall so that they do not burst when the central vacuole fills up with water. Prokaryotes do not have a nucleus, and lack membrane bound organelles.
They are the oldest cells on earth. Prokaryotes often move using special structures such as flagella or cilia. Cells have many structures inside of them called organelles. These organelles are like the organs in a human and they help the cell stay alive. Eukaryotes also have a golgi apparatus that packages and distributes proteins.