The average menstrual cycle is 28 days long. However, a normal cycle can be shorter or longer than this. It may be anywhere from 21 to 35 days long. Most periods last 3 to 5 days, but anywhere from 2 to 7 days is normal.Menstrual cycles may happen around the same date every month or they may be irregular.A menstrual period is considered late if it hasnât started 5 or more days after the day you expected it to start.A period is considered missed if you have had no menstrual flow for 6 or more weeks after the start of your last period.enstrual cycles may happen around the same date every month or they may be irregular. A menstrual period is considered late if it hasnât started 5 or more days after the day you expected it to start. A period is considered missed if you have had no menstrual flow for 6 or more weeks after the start of your last period.
Transcript of Theory of Dorothy Johnson. Theory of Dorothy Johnson. The Behavioral System Model. Johnsonâs Behavioral System Model is a model of nursing care that advocates the fostering of efficient and effective behavioral functioning in the patient to prevent illness.
Major nursing theorists and theories. 1  Anne Casey: Casey's model of nursing. 2  Betty Neuman: Neuman systems model. 3  Boykin & Schoenhofer. 4  Callista Roy: Adaptation model of nursing. 5  Carl O. Helvie: Helvie energy theory of nursing and health. 6  Dorothea Orem: Self-care deficit nursing theory. 7  Helen Erickson.