60. The absolute strength of certain muscles of a person. Dynamometry

Measurement of strength of individual human muscle groups by means of special devices - Dynamometer s health. Using hand dynamometers measure the strength of the muscles that bend your fingers, using a deadweight dynamometer - the strength of the muscles that straighten the body (“dead” force), etc. Dynamometric indicators can be expressed in absolute terms ( kgf ) and in relative values , for example, in relation to the mass (weight) of a person’s body. D.'s data are taken into account in anthropometry, professional selection, in physiology and occupational and sports hygiene, medicine, and are used as an additional sign for assessing the degree of a person’s physical development.

 

 

 

 

61. Synapses. Organization and classification.

Synapses are contacts that establish neurons as independent entities. They are a complex structure and consist of a presynaptic part (axon end, transmitting a signal), a synaptic cleft and a postsynaptic part (structure of a receptive cell).

Classification:

1) by location - neuromuscular and neuronuronal (axosomatic, axoaxonal , axodendritic, dendrosomatic );      

2) by the nature of the action - exciting and inhibitory;      

3) by the method of signal transmission - electrical, chemical, mixed.      

 

62. Neuroneuronal synapses.

- and the neuron xon is in contact with another neuron. Subdivided into:

a) axosomatic - with the body of another neuron;

b) axoaxonal   - with the axon of another neuron;

c) axodendritic - with the dendrite of another neuron.

The transmission of a nerve impulse through the synapse occurs with the help of mediators. Among the most important include: acetylcholine, norepinephrine, serotonin , dopamine, glutamate , GABA, endorphins and ecnephalins .

Synthesis of a mediator: the enzymes necessary for the formation of a neurotransmitter are synthesized in the pericarion and transported to the synaptic terminal along the axon, where they interact with molecules of neuronal precursors.

Storage: accumulates in the nerve terminal , being inside synoptic vesicles along with ATP and some cations. There are several thousand molecules in a bubble, which makes up a quantum.

 

63. The conjugation of pd with exocytosis of the mediator.

Any chem. the synapse is activated by PD, which extends to the presynaptic membrane from the body of the neuron. Under the action of its PD depolarization occurs that increases the permeability of Ca 2 + channels and leads to an increased entry into presinaps Ca . Calcium is needed for the interaction of membrane proteins of synoptic vesicles - synaptotagmine and synaptobrevin with plasma membrane proteins - syntaxin and SNAP- 25. As a result of their interaction, synoptic vesicles move to the active zones and adhere to the plasma . m embrane. After this, exocytosis begins . 100-200 quanta are being released. Having left in syn . Spruce , the mediator interacts with special. postsynaptic membrane receptors. They regulate the permeability of ion channels. There is an increase in permeability to sodium and calcium ions, which causes depolarization of the postsynaptic membrane.

 

Noticed a joke with confused numbers? :)