There are two types of myofibrils: actin and myosin
Actin myofibrils are placed between myosin ones and join with them through special bridges
These fibrils form the striated structure of muscle (fiber under the microscope shows light (I) and dark (A) zones)
In contraction actin fibril slide between myosin ones and I zone become shorter
Muscle fibers are covered by ENDOMYSIUM (1)
Bundles of muscle fibers are covered by PERIMYSIUM (2)
Muscle as a whole is covered by EPIMYSIUM (3)
The functional unit of muscle is myon
MYON is a bundle of muscle fibers, which is innervated by one nerve fiber
MUSCLE AS AN ORGAN consists of striated muscle tissue, connective tissue, nervous tissue, smooth muscle fibers
All connective tissue covering the muscle continues on both sides of muscle, forming the TENDON which are attached to bones
The tendon is formed by the dense connective tissue, containing collagen fibers and it sustains big load
The middle part of muscle is called BELLY
Attachment of muscles
• The origin (punctum fixum) – head of the muscle
• The insertion (punctum mobile) – tail of the muscle
Conception about Nervous system. Principles of organization of the nervous system. Simplex and compound reflex arcs. The development of the nerve system and congenital anomalies of the development
The activity of the nervous system is based on the reflex(I. M. Sechenov).
"This means that a nervous receptor receives a signal from an agent of the ezternal or internal world of the organism. This signal is transformed into. a nerve process, in a phenomenon of nervous stimulation. The nerve impulse payee along nerve fibers, as along wires, to the central nervous system and, from there, along established connections of other wires to the organ itself where it is transformed, in turn, into a specific process of the cells of this organ" (Pavlov).
The basic anatomical element of the nervous system is the nerve cell
which, together with all the proceres arising from it, is called the neuron.
A long axial cylindrical process, called the axon or neurite, arises from the body of the cell in one direction. Short branched processes called deadrize lead in the other direction.
The basic anatomical element of the nervous system is the nerve cell
which, together with all the proceres arising from it, is called the neuron.
A long axial cylindrical process, called the axon or neurite, arises from the body of the cell in one direction. Short branched processes called deadrize lead in the other direction.
Fundamental reaction of the nervous system go throw reflex arch
Simple reflex arch (2neurons)
1. Receptors transform the energy of the external stimulus into a nerve process; tbe receptors are connected with afferent (centripetal or receptor) neurons, which transmit the triggered excitation (nerve impulse) toward the centre; the analysis begins this phenomenon (Pavlov).
2. Conductors are internuncial or connecting neurons which accomplish the contact, i.e. the transfer of the nerve impulse from the centripetal to the centrifugal neuron and the transformation of the impulse received by the centre into an external reaction. This synthesis "evidently repreamts the phenomenon of the nerve connector" (Pavlov). This is why Pavlov calls this neuron the connector.
3. Efferent (centrifugal) neurons implement response reactions (motor or secretory) by conducting the nervous impulse from the centre to the effector (the producer of the effect or the action) at the periphery, i.e. to the working organ (muscle, gland).
Compaund reflex (more than 2 neurons)
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