Els vasos sanguinis :







Els vasos sanguinis són conductes de parets elàstiques per on circula la sang. N'hi ha de tres tipus: artèries, venes i capil·lars.

Les artèries transporten la sang del cor a la resta del cos. Tenen les parets gruixudes.

Les venes transporten la sang de les diferents parts del cos cap al cor. Tenen les parets primes.

Els capil·lars són vasos molt fins que comuniquen les artèries amb les venes. En els capil·lars es produeix l'intercanvi de substàncies entre la sang i les cèl·lules.

El cor i la circulació de la sang:





El cor és un múscul de la mida del puny situat entre els pulmons. Gràcies al seu moviment de contracció i dilatació, fa circular la sang pels vasos sanguinis.

El cor té quatre cavitats: les dues superiors s'anomenen aurícules i les dues inferiors ventricles. La sang entra per les aurícules, passa als ventricles, i aquests l'expulsen amb força cap a l'exterior.

En el cos hi ha dos circuits sanguinis diferents, el pulmonar i el general.

• *En el circuit pulmonar, la sang va del cor als pulmons, i dels pulmons al cor.Als pulmons, la sang expulsa el diòxid de carboni i absorbeix l'oxigen de l'aire.

*En el circuit general, la sang va del cor cap a les diferents parts del cor (cap, extremitats, intestins, ronyons, etc.) i torna de nou al cor.

En el circuit general, la sang proporciona substàncies nutritives i oxigen a les cèl·lules. Les cèl·lules transformen aquestes substàncies en energia, i generen substàncies residuals i diòxid de carboni que aboquen a la sang, la qual s'encarregarà d'expulsar-les del cor.

El funcionament del cor:

The circulatory system is made up of the vessels and the muscles that help and control the flow of the blood around the body. This process is called circulation. The main parts of the system are the heart, arteries, capillaries and veins.
As blood begins to circulate, it leaves the heart from the left ventricle and goes into the aorta. The aorta is the largest artery in the body. The blood leaving the aorta is full of oxygen. This is important for the cells in the brain and the body to do their work. The oxygen rich blood travels throughout the body in its system of arteries into the smallest arterioles.
On its way back to the heart, the blood travels through a system of veins. As it reaches the lungs, the carbon dioxide (a waste product) is removed from the blood and replace with fresh oxygen that we have inhaled through the lungs.

this is a video that explain the digestion process

this is a picture that contains all the tissues.
Epithelial Tissue: Epithelial tissue covers the outside of the body and lines organs and cavities. The cells in this type of tissue are very closely packed together and joined with little space between them. As we have previously discussed, structure and function are thoroughly intertwined throughout biology and epithelial tissue is no exception. With a tightly packed structure we would expect epithelial tissue to perhaps serve some type of barrier and protective function and that is certainly the case. Epithelial tissue helps to protect organisms from microorganisms, injury and fluid loss. In an epithelium, the free surface is usually exposed to fluid or the air while the bottom surface is attached to a basement membrane.A simple epithelium has a single layer of cells.A stratified epithelium has multiple layers of cells. Likewise, the shape of the cells on the free surface can be: Cuboidal Analogous to the shape of dice.Columnar Analogous to the shape of bricks on an end.Squamous Analogous to the shape of flat tiles on a floor.Connective Tissue:
Connective tissue serves many purposes in the body:bindingsupportingprotectingforming bloodstoring fatsfilling spaceConnective cells are separated from one another by a non-cellular matrix. The matrix may be solid (as in bone), soft (as in loose connective tissue), or liquid (as in blood). Two types of connective tissue are Loose Connective Tissue (LCT) and Fibrous Connective Tissue (FCT). Fibroblasts (LCT) are separated by a collagen fiber-containing matrix. Collagen fibers provide elasticity and flexibility. LCT occurs beneath epithelium in skin and many internal organs, such as lungs, arteries and the urinary bladder. This tissue type also forms a protective layer over muscle, nerves, and blood vessels.
The cells of connective tissue are embedded in a great amount of extracellular material. This matrix is secreted by the cells. It consists of protein fibers embedded in an amorphous mixture of protein-polysaccharide ("proteoglycan") molecules.Supporting connective tissueGives strength, support, and protection to the soft parts of the body.cartilage. Example: the outer earbone. The matrix of bone contains collagen fibers and mineral deposits. The most abundant mineral is calcium phosphate, although magnesium, carbonate, and fluoride ions are also present. [More on bone]Binding connective tissueIt binds body parts together.Tendons connect muscle to bone. [View] The matrix is principally collagen, and the fibers are all oriented parallel to each other. Tendons are strong but not elastic.Ligaments attach one bone to another. They contain both collagen and also the protein elastin. Elastin permits ligaments to be stretched.Fibrous connective tissueIt is distributed throughout the body. It serves as a packing and binding material for most of our organs. Collagen, elastin, and other proteins are found in the matrix.Fascia is fibrous connective tissue that binds muscle together and binds the skin to the underlying structures.Adipose tissue is fibrous connective tissue in which the cells have become almost filled with oil. The oil is confined within membrane-bound droplets. The cells of adipose tissue, called adipocytes, secrete several hormones, including leptin and adiponectin.All forms of connective tissue are derived from cells called fibroblasts , which secrete the extracellular matrix.
Nerve:
Nerve tissue is composed ofnerve cells called neurons andglial cells.NeuronsNeurons are specialized for the conduction of nerve impulses. A typical neuron consists ofa cell body which contains the nucleus;a number of short fibers — dendrites — extending from the cell bodya single long fiber, the axon.The nerve impulse is conducted along the axon.
The tips of axons meet:other neurons at junctions called synapsesmuscles (called neuromuscular junctions)glands
GliaGlial cells surround neurons. Once thought to be simply support for neurons (glia = glue), they turn out to serve several important functions.There are three types:Schwann cells. These produce the myelin sheath that surrounds many axons in the peripheral nervous system.Oligodendrocytes. These produce the myelin sheath that surrounds many axons in the central nervous system (brain and spinal cord).Astrocytes. These — often star-shaped — cells are clustered around synapses and the nodes of Ranvier where they perform a variety of functions:stimulating the formation of new synapses;modulating the activity of neurons;repairing damage;supplying neurons with materials secured from the blood. (It is primarily the metabolic activity of astrocytes that is being measured in brain imaging by positron-emission tomography (PET) and functional magnetic resonance imaging (fMRI).In addition, the central nervous system contains many microglia — mobile cells that respond to damage (e.g., from an infection) byengulfing cell debrissecreting inflammatory cytokines like tumor necrosis factor (TNF-α) and interleukin-1 (IL-1)
Blood :
The bone marrow is the source of all the cells of the blood. These include:red blood cells (RBCs or erythrocytes)five kinds of white blood cells (WBCs or leukocytes)platelets (or thrombocytes)
Muscle:
Three kinds of muscle are found in vertebrates:Skeletal muscle is made of long fibers whose contraction provides the force of locomotion and other voluntary body movements.Smooth muscle lines the walls of the hollow structures of the body, such as the intestine, urinary bladder, uterus, and blood vessels. Its contraction, which is involuntary, reduces the size of these hollow organs.The heart is made of cardiac muscle.

Respiratory apparatus: set of organs of respiration.
Nasal cavity: chamber of the nose.
Oral cavity: chamber of the mouth.
Epiglottis: fold of cartilage that closes the glottis during swallowing.
Trachea: tube connecting the larynx to the bronchi.
Cartilage: crest that separates the openings of the right and left bronchi.
Left lung: left respiratory organ.
Oblique fissure: separation between the two pulmonary lobes.
Diaphragm: large, thin muscle that separates the chest from the abdomen.
Esophagus: part of the digestive tract between the pharynx and the cardia of the stomach.
Alveola: small pulmonary cavity where gas exchange takes place.
Right lung: right respiratory organ.
Right bronchus: tube connecting the larynx to the lungs.
Terminal bronchiole: division of the bronchus that ends in a cluster of alveola.
Larynx: voice organ situated between the pharynx and the trachea.
Pharynx: part of the digestive tube between the mouth and the esophagus.