Explanation:
Synapses are junctions at axon terminals where they connect to dendrites of other neurons at these junctions chemical reactions occur in order to facilitate the passage of information as chemical signals. There are several neuron types which include sensory motor and into neurons which bridge the two.
1. At neuromuscular junctions, electrical signals are transmitted:
- The action potential travels along the membrane until the synapse where it’s electrical depolarization leads to the opening of channels allowing only sodium ions to enter
- these flow through a presynaptic membrane until the concentration is built up, activating ion sensitive proteins attached to vesicles containing neurotransmitters like acetylcholine
- this leads to changes in the proteins leading to the fusion with the membrane of the presynaptic cell, so vesicles are open and neurotransmitter is released. The neurotransmitter diffuses across to chemical receptors on the presynaptic cell where they bind temporarily. This increases the permeability of the sarcolema to Na+;a new action potential is generated
2. Contraction of the sarcomere occurs via several steps.
- This action potential in the muscle, travels along T-tubules, and Ca+ ions are released by the sarcoplasmic reticulum into the sarcoplasm
- Ca and troponin combine, pulling myosin filaments, exposing the actin filament's myosin binding sites
- cross-bridge formation occurs, leading to the sliding of filaments.
- ATP drives cross-bridge cycling while mysosin pulls on actin strands
- muscle fibers shorten and contract
- later ACH is degraded in the synapse. Na ions are not released, and the action potential is not transmitted.
- the Ca channels on the SR close, while Ca is reabsorbed stopping Ca-troponin binding, closing myosin binding sites on actin and leading to cross bridge separation. The muscle fiber relaxes in their resting states.
Learn more about the autonomic nervous system at brainly.com/question/10386413
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Answer:
These cells have specific types of receptors on their membranes.
An argument.
An opinion is never correct nor incorrect they are all valid in their own right. So that eliminates b. It’s true that it can’t be proven to true or false however, some opinions have no evidence so they have no warrant to be proven or disproven. An argument however, is how you argue for what you believe in, you provide examples, to prove you’re right. To prove your opinion so I believe that D is the best option here.
Answer:
a person or thing that prevents incompatible or antagonistic people or things from coming into contact with or harming each other:
Explanation:
A
. Leaves were trapped between layers of sediment millions of years ago, causing the imprint
Explanation:
The only true explanation that perfectly describes the rock is that the leaves were trapped between the layers of sediment millions of years ago causing the imprint.
Leaf imprints are often referred to as trace fossils.
- Trace fossils points to the different life activities an organism must have been engaged in.
- When a leaf is trapped in a soft sediment between two layers, the compaction of the sediment can duplicate the form of leaf on beds.
- This gives a physical overview to the nature of leaf.
- Such an imprint did not grow, and cannot be attributed to metamorphic processes(option D).
- Option C is completely wrong
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Fossil records brainly.com/question/12790206
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