» Page 22

Myology (MYOLOGIA) - the science of muscles

Myology (MYOLOGIA) - the science of muscles

Development of the muscles

The muscles and fascia develop from myotomes, including from the dorsal part of myotomes develop deep back muscles, from the ventral part of myotomes - the muscles of the front and literal surface of the body (muscles of the chest, abdomen, neck). The diaphragm develops from the sixth cervical myotome. At the end of 4-th week of fetal development, muscles of limbs develop from buds of limbs. From buds of mesoderm the anterior of 4 lower cervical and first thoracic myotomes develop muscles of the upper limbs. Chewing and mimic muscles, some muscles of the neck, the muscles of the soft palate, throat, larynx develop from the mesoderm of gill arches.

Arthrology (ARTHROLOGIA) - the science of bones connection

Arthrology (ARTHROLOGIA) - the science of bones connection

The connections of the bones - articulatio.

Development of the bones connections.
On 6-7 th week between the cartilage bones models occurs the concentration of mesenchyme. Then development of the bones connections goes by two ways:
1) from the mesenchyme forms fibrous or cartilaginous tissue (development of the uninterrupted bones connection);
2) liquefaction of the mesenchyme (development of the interruptions bones connection).

Classification of the bones connections:
I. Uninterrupted connection - synarthrosis:
1.1. Fibrous connection:
1.1.1. Syndesmosis - connection of the bones by ligaments and membranes.
1.1.2. Connection of the bones skull.
1.1.3. Herniation –zubo alveolar connection.
1.2. Cartilage connection - synchondrosis;
- Constant;
- Temporary;
- Symphysis.
1.3. Bone connection - synostosis
II. Discontinuous connection - diarthrosis;

Development of the skeleton

Bone tissue develops from the mesenchyme. At the end of the 1st month of fetal development are formed clusters of mesenchyme, which form the membrane models for future bones. This is stage of development of membranous bones. From 2nd month cells begin to produce chondrin and comes cartilage stage. With 6-7 weeks begins bone stage of development of bones. But the bones of the cranial vault, the bones of the face, medial plate of pterygoid process, the middle part of the clavicle in their development have no cartilage stage and are called primary bones. With the development of bone by the direct (membranous) ossification in young connective tissue (mainly in the center of the future bone) appears one or more points of the ossification. Point of the ossification consists of the osteoblasts (young bone cells ), placed in the form of beams. Beams grow, forming a skeletal grid, in loops of which are located bone marrow cells and blood vessels. Osteoblasts produce intercellular substance in which are deposited salts of calcium. Gradually osteoblasts transformed to osteocytes (mature bone cells), are formed the inner and outer plates of compact bone substance, sponge substance, surface layers of connective tissue are converted to the periosteum. The bones of the trunk, limbs, skull base develop on the site of cartilage and are called secondary bones. With the development of the bone by indirect ossification, the bone formation can occur on the periphery of the cartilage - perichondral ossification, or from the middle of cartilage - enchondral ossification.

Ossification of long tubular bones in the area of diaphysis carried by perichondral and enchondral way. The first point of ossification appears in the center of cartilage model of bone on the 8th week of embryogenesis.

Osteology (OSTEOLOGIA) - the science of the bones

Osteology (OSTEOLOGIA) - the science of the bones

Classification of bones:
- Tubular bones - have a body - diaphysis (diaphysis) and end - epiphysis. Between the diaphysis and the epiphysis is the "growth zone" - metaphysis, by which the bone grows in length. Tubular bones can be long and short. Long tubular bones perform locomotor function, short - supporting.
- Trabecular bones are short, have a shape of an irregular cube.
- Flat bones are wide, are involved in the formation of a body cavity serve a protective function.
- Mixed bones are complex. Have elements of the flat and trabecular bones.
- Pneumatic bones - have a cavity filled with air.

Bones structure

Every bone is an independent organ. Living human bone contains of 50% water, 28.15% of organic substances and 21.85% of inorganic compounds (compounds of calcium, phosphorus, magnesium, etc.). Macerated (bleached, dried) bone consists of 1/3 organic substances and 2/3 of inorganic chemicals. With the predominance of organic substances in the bone (children), the bone is more flexible; with the predominance of inorganic substances (older people) - the bone is crisp. The bone is composed of bone tissue. The outer layer of the bones are formed by compact substance (substantia compacta), which consists of lamellar bone tissue through which pass thin bone tubules (some of which are parallel to the surface of the bone, others - perpendicular). Bone tubules is a continuation of feeding channels (candles nutricia), which open on the surface of the bone. Through feeding channels occurs power supply and innervation of the bone, because through them pass arteries, veins and nerves. The structural unit of the bone is osteon or Haversian system.

Development of the human organism

Development of the human organism - ontogenesis - is divided into two periods: prenatal (intrauterine) and postnatal (extrauterine). Utero period lasts from the moment of fertilization and to the birth of a child and also consists of two phases: embryonic (first 2 months) and fetal (3 to 9 months). At the moment of fertilization male germ cell - spermatozoon (sperm) - penetrates into the female sex cell - ovule (oocyte), causing appears a zygote. Fertilization usually occurs in the fallopian tube. Zygote (single-celled embryo) has all the properties of both gametes.

1st week of embryonic development - is crushing, in which one of the cells formed many cells - blastomeres that form multicellular blastula. Crushing lasts 3-4 days in the fallopian tube, and then continues in the uterus. By the end of the 1st week formed a bubble - blastocyst, which consists of internal group of cells - Embryoblast and peripheral group of cells - the trophoblast (lines the surface of Embryoblast). Between embryoblast trophoblast and a cavity filled with mesenchyme. The embryo begins to take root in the mucous membrane of the uterus (implantation). Trophoblast cells secrete the enzyme, loosening the surface layer of the endometrium and give outgrowths - villi and turn into villous membrane - chorion. From the chorion and endometrium neighboring to it developing placenta. From embryoblast formes the embryo.

Cells, tissues, organs, organs systems and organs apparatus

Cells, tissues, organs, organs systems and organs apparatus

Cell (cellula) is a microscopic formation, elementary particle of a living organism, but is a complex system that contains the nucleus and cytoplasm. The sizes of the cells are from a few micrometers to 200 micrometers. Cell shape is different (spherical, spindle-shaped, flat, cubic, prismatic, cylindrical, star-shaped, with spikes). Cell structure is difficult. Externally, every cell has a membrane - cytolemma (plasmolema). Cytolemma - is a semi-permeable membrane through which performes the transport of substances and the interaction of cells with neighboring cells and intercellular substance. In the cell is contained nucleus, which is involved in protein synthesis and keeps genetic information. The core is covered with shell - cariolema. The core filled nucleoplasm (carioplasma), which have 1-2 nucleolus and chromatin. Around the core is placed cytoplasm. The composition of the cytoplasm included cytosol, organelles and cytoplasmic inclusions. Cytosol - is free of organelles substance of cytoplasm semi-liquid, semi-transparent, is involved in the metabolism. Organelles - constant part of cells that perform specific functions.

Organelles include:
- Mitochondria - the energy cell organelles are involved in the processes of oxidation, phosphorylation;
- Internal mesh apparatus (lamellar complex or Golgi apparatus), which consists of vesicles, plates, tubes, synthesize polysaccharides is involved in removing of products of its life to outside of the cell;
- Cytoplasmic (endoplasmic) grid - formed by tubes and plates. Non-granular cytoplasmic grid involved in the metabolism of lipids and polysaccharides. Granular cytoplasmic grid contains spherical granules - ribosomes and their clusters - polysomes (polyribosomes). Granular cytoplasmic grid is involved in protein synthesis. Cytoplasmic inclusion - is the accumulation of various substances (protein, fat, pigment and others creations).

The organism and its integrity

Organism (from the Greek. Organon - organ) is defined as any whole alive plant or animal, including the man. The main properties of the organism are: constant exchange of substances and energy (internal and with the environment), self-renewal, movement, reactivity, self-development and growth , heredity and variability, adaptability to conditions of existence. The more complex the structure of the body, the better it retains constant internal environment (homeostasis (body temperature, blood biochemical composition, etc)) regardless of environmental conditions. For human, unlike animals, external factors of the leading importance attaches to socio-economic conditions.

The evolution of the animals occurred by increase in the level of life organization: molecular, cytoplasmic (unicellular protozoa), cell (sponge), tissue organisms (coelenterates), higher animals (with complex of organs). Evolution included two opposite processes: differentiation or division of the body for tissues, organs, systems of organs(with appropriate and the simultaneous distribution and specialization of functions) and integration, or combining of pieces into an integral organism, sealed humoral and neural connections. The highest organisms, including man, preferably is inherent a system level of performance. The presence other levels of functioning is not disputed but they have a subordinate character.

Man in Nature

Modern man in the classification system of animal organisms belongs to the type of chordates (Chordata), a subtype of vertebrates (Vertebrata), the class of mammals (Mammalia), a number of primates (Primates), friendly of people (Hominidae), kind of man (Homo), species Homo sapiens (Homo sapiens). The human body keeps a general structure, inherent in all vertebrates: bilateral symmetry, the prevalence of paired organs, the presence of the axial skeleton, saving some (relic) signs of segments (metamerism), better detected in primitive form. These and many other features (reduced state of smell saved some rudiments of caudal vertebrae, the presence of the rudiments of the third eyelid, etc.) testify to ways the evolution past zoological ancestors.

The main morphological features of the human body compared to other primates body include: functional forelimbs (in human upper limb - arm), high growth and differentiation of the mantle (cortex) of the brain, a significant weakening of the jaw apparatus, equal number of teeth, lack of overall hair , upright posture, prolonged childhood and so on. Modern man owns expressive language, interconnected with abstract thinking (development of the second signal system). However, the main distinguishing feature between man and animal is that people - a social being, the main condition and formation of life is socially useful labor, is closely associated with the emergence of society.