It is pulling your foot away after stepping on a sharp object
The cells of the SA node at the top of the heart are known as the pacemaker of the heart because the rate at which these cells send out electrical signals determines the rate at which the entire heart beats (heart rate). The cells that create these rhythmic impulses, setting the pace for blood pumping, are called pacemaker cells, and they directly control the heart rate. They make up the cardiac pacemaker, that is, the natural pacemaker of the heart. Hope this helps!
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It marks the end of reproductive ability.
The family is a basic unit of study in many medical and social science disciplines. Definitions of family have varied from country to country, and also within country. Because of this and the changing realities of the current times, there is a felt need for redefining the family and the common family structure types, for the purpose of study of the family as a factor in health and other variables of interest. A redefinition of a “family” has been proposed and various nuances of the definition are also discussed in detail. A classification scheme for the various types of family has also been put forward. A few exceptional case scenarios have been envisaged and their classification as per the new scheme is discussed, in a bid to clarify the classification scheme further. The proposed scheme should prove to be of use across various countries and cultures, for broadly classifying the family structure. The unique scenarios of particular cultures can be taken into account by defining region or culture-specific subtypes of the overall types of family structure.
The family as an integrated and functional unit of society has for a considerable period of time captured the attention and imagination of researchers.[1] While the family itself is a matter of study, equally important for research is its role as a factor influencing and affecting the development, behavior, and well-being of the individual. The family is a basic unit of study in many social science disciplines, such as sociology, psychology, economics, anthropology, social psychiatry, and social work.[2] It is also a unit of study in the medical sciences especially in understanding the epidemiology and the natural history of diseases. It also forms the basic unit for family medicine. Census definitions of family have varied from country to country and also from census to census within country. The word household has often been used as a replacement for family. Using the definition as “all people living in one household” may be erroneous, as on one hand it may include people who do not share kinship, and on other hand may exclude those kin members who are temporarily away.[3] This type of definition fails to identify units that function as families in an economic, social or emotional sense but do not usually reside in the same household.[4] Although the literature often focuses on family living arrangements, family membership includes obligations across and between generations, no matter where family members are living.[5]
