- •46. Dependence of the amplitude of contraction on the strength of the stimulus in the initial muscle length ( sarcomere length )
- •47. Summation of muscle contraction and its types
- •48. Changes in the excitability of muscle fibers during excitation
- •49. The mechanism of summation of muscle contractions
- •50. Thetanus and its species.
- •51. The mechanism of occurrence of tetanic contractions.
- •52. The dependence of the amplitude of the tetanus on the frequency of irritation
- •53. Muscle tone and its difference from tetanus.
- •54. Work and muscle power. Types of work: dynamic (overcoming and inferior) and static (holding). The law of medium loads.
- •55. The contractile activity of muscles in the human body.
- •57. Concepts of the general and absolute strength of muscles .
- •60. The absolute strength of certain muscles of a person. Dynamometry
- •61. Synapses. Organization and classification.
- •62. Neuroneuronal synapses.
- •63. The conjugation of pd with exocytosis of the mediator.
- •69. The role of mediators in the mechanism of formation of epsp and tpps.
- •70. Characterization of epsp and tpsp in duration and amplitude.
- •71. The number of synapses on spinal cord motor neurons .
- •72. The mechanism of integration of epsp and tpps neuron.
55. The contractile activity of muscles in the human body.
The contractile ability of the skeletal muscle is characterized by the contraction force that muscle a develops ( evaluate the Total Strength - develops the muscle, and the Absolute Strength - coming 1 cm square cross section), the length of the shortening, the degree of muscle fiber tension, the speed of shortening and development of tension, the speed relaxation.
Annoyed mouse . Fibers with a single threshold or superthreshold stimulus lead to the appearance of a single contraction, which consists of several periods. The first is latent , which is the sum of time delays due to excitation of the mouse membrane . fiber, the spread of PD through the T-system into the fiber, the formation of inositol triphosphate , an increase in the concentration of intracellular calcium and the activation of transverse bridges. Vtoroe d- period shortening, or the development of stress. In the case of free shortening of the mouse . the fibers speak of an isotonic contraction mode, in which the voltage remains practically unchanged , and only the length of the mouse changes . fiber. If a mouse . the fiber is fixed on both sides and cannot be freely shortened, it is said that the contraction mode is isometric. In this mode, abbr. mouse length . fiber does not change, while the size of sarcomeres change due to the sliding of actin and myosin filaments relative to each other. Third perio railway relaxation when concentration decreases Ca 2+ and disconnected from the myosin head actin filaments . (further pages 83-84 smooth and serrated titanus )
.№56. Parameters characterizing muscle contractility.
Skeletal muscle contractility characterized ized power reduction that develops muscle (usually estimated total power that can develop the muscle, and absolute, t. E. Power per 1 cm2 cross-section) .d Lina shortening of, degree of muscle fiber stress rate shortening of time and voltage Vitia, According Since these parameters are largely determined by the initial length of the muscle fibers and the strain on the muscles, the study of the contractile ability of muscles to produce various Regis max.
57. Concepts of the general and absolute strength of muscles .
Strength and muscle work. Distinguish between absolute and absolute power . The total strength is determined by that maximum load, the muscle is still able to lift. This value depends on the structure of the muscle, its functional state, the influence of the central nervous system and other factors. Strength is greater, the larger the diameter and the “physiological” muscle cross section. The strength of muscles with an oblique arrangement of fibers is greater than with a longitudinal one. Absolute strength is the ratio of maximum strength to the cross-sectional area of the muscle. This value allows you to compare the strength of the various muscles of one organism and the strength of the muscles of various animals. For example, the absolute strength of the human gastrocnemius muscle is 5.9 kg / cm 2 , chewing 10 kg / cm2, triceps brachii - 16.8 kg / cm2. When training muscles, accompanied by their working hypertrophy, muscle strength increases significantly.