Table of Contents
Who discovered gap junction?
“Cells live together, but die singly”, this sentence wrote the German physiologist Theodor Engelmann in 1875 and although he had no particular knowledge of gap junction channels (their structure was discovered around 100 years later) he described their functions very well: gap junction channels are essential …
Where is gap junction located?
Location. Gap junctions are found in many places throughout the body. This includes epithelia, which are the coverings of body surfaces, as well as nerves, cardiac (heart) muscle, and smooth muscle (such as that of the intestines). Their primary role is to coordinate the activity of adjacent cells.
How is a gap junction formed?
Gap junctions are formed by the apposition of connexons from adjacent cells, where each connexon is formed by six connexin proteins (Fig. 1A). There are 21 different connexin genes in the human genome and 20 in mice. Connexins are tetraspan transmembrane (TM) domain proteins with intracellular N- and C-termini (Fig.
What is synaptic gap?
Medical Definition of synaptic cleft : the space between neurons at a nerve synapse across which a nerve impulse is transmitted by a neurotransmitter. — called also synaptic gap.
What is gap junction in cardiac muscle?
In the heart, individual cardiac muscle cells are linked by gap junctions. These junctions form low resistance pathways along which the electrical impulse flows rapidly and repeatedly between all the cells of the myocardium, ensuring their synchronous contraction.
Qu’est-ce que les jonctions communicantes?
Les jonctions communicantes sont ainsi essentielles à la communication entre les cellules. Chaque jonction est composée de très nombreux canaux composés de molécules variables (connexines) conférant aux jonctions communicantes des propriétés différentes.
Pourquoi les jonctions sont-elles importantes?
Les membranes cellulaires étant polarisées (environ −70 mv), les jonctions permettent de faire en sorte que toutes les cellules soient au même potentiel. Cette particularité a été plus étudiée chez les invertébrés et plus particulièrement chez les arthropodes.
Pourquoi les jonctions communicantes disparaissent après l’accouchement?
Quarante-huit heures après l’accouchement, les jonctions communicantes disparaissent, l’utérus perd la faculté de se contracter en bloc . (en) Robert Garfield, Mariam Ali, Chandrasekhar Yallampalli et Hidetaka Izumi, « Role of gap junctions and nitric oxide in control of myometrial contractility », Semin.
Pourquoi les jonctions communicantes sont-elles importantes avant l’accouchement?
Juste avant l’accouchement, on observe une multiplication par cinq du nombre de jonctions communicantes au niveau du muscle utérin. Cela permettrait à l’utérus d’effectuer des contractions synchrones et de développer la force nécessaire à l’accouchement.