Answer:
Myelinated Axons; leak channels are insulated by myelin leading to less loss of current flow and better conduction velocity. Ion channels omly located at nodes of ranvier; thus signal has sultatory conduction along myelin sheaths and jumps and move much quicker
Demyelinating diseases; along locations where myelin sheaths once was current links occur and conduction slows, the signal cannot make it very far because it looses energy as it travels through the axon
Unmyelinated axon; Ion channels are sequentially placed all along axons; thus it takes longer to send signal down axon. the energy isn't leaked out, it still contains the same signal but it is simply slower. distance between voltage gated channels needs to be small enough so local current flow can depolarize the membrane.
N/B; Harder to generate action potential in demyelinating disease
axon diameter( bigger diameter= less resistance= faster current).
Answer: C. Multiple outcomes can be evaluated from a single exposure
Explanation:
Cohort studies continue with a disease-free group of people (a cohort). The cohort's people are divided by whether or not they're prone to a possible cause of illness. The entire cohort is monitored over time to see how the emergence of new cases of the disease (or other outcome) varies with and without exposure between the classes.
In a case-control analysis too, the same disease can be studied. A case-control research starts with the collection of cases including people with a disease and the tests which includes people without the disease. The controls would represent people who would have been cases of research had the disease formed (population at risk).
The advantage of Cohort studies over a case-control study involves that one can determine variety of outcomes/diseases caused by one exposure for example, lung disease, heart disease, and smoking-caused renal disease.
Hence, the correct option is C." Multiple outcomes can be evaluated from a single exposure".
Answer:
"AV node" receives the depolarization wave from the atria and passes impulses onto the ventricles.
Explanation:
The atrioventricular node or AV node is a portion of the electrical conduction system of the heart that organizes the top of the heart. It electrically attaches the atria and ventricles. The AV node is a bunch of cells in the middle of the heart among the atria and ventricles, and performances like a gate that decelerates the electrical signal before it enters the ventricles. This postponement gives the atria time to contract before the ventricles do.
Future differences I think
<span><span>A. </span>B-cells
</span>
Which type of white blood cells is produced in the thymus and destroys the
cell membranes of bacteria are B-cells. These b-cells are also known and called as B
lymphocytes. Their function primarily is to create antibodies which combats
antigens such as bacteria. They are also responsible for immune regulatory
indications –cytokines. In contrast, T-cells are a type of white blood cells
that combat any substance from the inside or within the body.
