The first one is the answer i think dont quote me <span />
Answer:
The cardiac muscle is made up of branched muscle cells, which have 1 or 2 nuclei and which the contact area between the heart fibers gives rise to specialized regions at the level of the plasma membrane called intercalary discs. The intercalary discs unite the cardiac muscle cells with each other, which provides greater adhesion to the tissue and intervenes in the rapid communication between cells. This allows its simultaneous contraction and the production of the beat.
Explanation:
The intercalary discs are the union systems that associate the cardiac muscle cells to form the myocardial fibers, the cardiac muscle is the muscle tissue of mixed components, which is located exclusively in the walls of the heart. For this reason, it has the function of generating the necessary contractions for the blood to reach all parts of the body.The intercalary discs are a special type of intercellular junction, a gap that guarantees electrical communication between these cells; and on the other hand, it provides places of adhesion and anchorage of one cell with another. The intercalary discs provide the structural foundation that allows the heart to behave as a functional syncytium.
True.
Explanation:
Cardiac muscle and some types of smooth muscle have the ability to contract without any external stimuli.
These muscles are called involuntary muscles.
Involuntary muscle are named so because,these muscles are independent of voluntary control and are controlled by our autonomic nervous system.
These are also known as white or smooth muscle.
Examples, muscles of heart, muscles of alimentary canal etc.
Answer:
The correct answer is e. <em>Postzygotic barrier.</em>
Explanation:
Different species can not mate and produce viable, healthy and fertile descendence, due to certain mechanisms of <u>reproductive isolation</u>.
These mechanisms involve different kinds of barriers that make it difficult for two different species to produce viable and fertile progeny.
One of these is the <u>postzygotic barrier</u>, which avoids the hybrid zygote to develope to adultness. In these situations, there is a mix of chromosomes that can not happen to meet or that they lack information.
There are cases in which the embryo dies, but some times the individual can reach some more advanced develope stages. If this is the case, in general, they can not survive because the organism is unhealthy. And if they reach adultness in good sate they can not leave descendence, as they are sterile.
Answer: Paracrine
Explanation:
Paracrine signaling is a form of cell signaling in which a cell produces a signal that induces changes in nearby cells, altering the behavior or differentiation of those cells. Molecules known as paracrine factors diffuse over relatively short distances (local action), unlike endocrine factors (hormones that travel considerable distances over the circulatory system), juxtacrine interactions, and autocrine signaling.
<u>Cells that produce paracrine factors secrete them into their immediate extracellular environment. </u>These factors then travel to nearby cells where the gradient of the factor received determines the outcome. However, the exact distance a paracrine factor can travel is not known with certainty. Paracrine signaling is a form of cell signaling in which a cell produces a signal that induces changes in nearby cells, altering the behavior or differentiation of those cells. <u>Molecules known as paracrine factors diffuse over relatively short distances</u>, unlike endocrine factors (hormones that travel considerable distances over the circulatory system), juxtacrine interactions, and autocrine signaling.
Cells that produce paracrine factors secrete them into their immediate extracellular environment. These factors then travel to nearby cells where the gradient of the factor received determines the outcome. However, the exact distance a paracrine factor can travel is not known with certainty.
In the case of infection, cells of the innate immune system secrete different cytokines into their immediate extracellular environment that attract other immune system cells such as neutrophils and lymphocytes, to fight the infection.
