Zygotene

Crossing over occurs in metaphase when all the chromosomes are aligned in the middle of the cell. Their close proximity allows crossing over to occur. Crossing over occurs in telophase right before the cells split since all the DNA and cell growth has occurred by this point.

While meiosis I, meiosis II, and mitosis all include prophase, synapsis is restricted to prophase I of meiosis because this is the only time homologous chromosomes pair with each other. There are certain rare exceptions when crossing-over occurs in mitosis.

It allows matching-up of homologous pairs prior to their segregation, and possible chromosomal crossover between them. Synapsis takes place during prophase I of meiosis. When homologous chromosomes synapse, their ends are first attached to the nuclear envelope.

The tight pairing of the homologous chromosomes is called synapsis. The synaptonemal complex supports the exchange of chromosomal segments between non-sister homologous chromatids, a process called crossing over. Crossing over can be observed visually after the exchange as chiasmata (singular = chiasma) (Figure 1).

electrical synapses

Synapses connect neurons in the brain to neurons in the rest of the body and from those neurons to the muscles. This is how the intention to move our arm, for example, translates into the muscles of the arm actually moving.

synapses. In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. In many synapses, the presynaptic part is located on an axon and the postsynaptic part is located on a dendrite or soma.

The small junction across which a nerve impulse passes from one nerve cell to another nerve cell, a muscle cell, or a gland cell.

Synapse: A specialized junction at which a neural cell (neuron) communicates with a target cell. At a synapse, a neuron releases a chemical transmitter that diffuses across a small gap and activates special sites called receptors on the target cell.

Synapses are microscopic gaps that separate the terminal buttons of one neuron from receptors (usually, located on the dendrites) of another neuron. When neurons communicate, they release chemicals that must travel across this gap to stimulate the post-synaptic receptors.

A synapse is a connection between two neurons in the brain. This junction is where nerve impulses, or messages, travel from one neuron to the next. Without the synapse, the message won’t get through. You have an important message. Synapse Writing & Editing will ensure that it gets through to your target audience.

John Morrison: A synapse is the point of communication between two neurons. In other words, fire and then activate the neurons that it synapses on and whether or not that neuron will learn because we now know that learning involves changing the synapses.

The number of synapses in the brain is known much less precisely, but is probably about 10¹⁴. For instance Human-memory.net reports 10¹⁴-10¹⁵ (100 – 1000 trillion) synapses in the brain, with no citation or explanation.