Introduction to the human body SURVIVAL NEEDS OF THE BODY (specialised temperature sensitive nerve endings) Learning outcomes Control centre After studying this section you should be able to (groups of cells in the hypothalamus of the brain a describe the role of the body transport systems inhibition Stimulation a outline the roles of the nervous and endocrine skeletal muscles(shivering m outline how raw materials are absorbed by the state the waste materials eliminated from the bod nore clothes, curling up m outline activities undertaken by an individual for protection and surviva Loss of body heat By convention, the body systems are described sepa rately in the study of anatomy and physiology, but in reality they are all interdependent. This section provides r Body temperature an introduction to body activities linking them to sur- Figure 1. 4 Example of a physiological negative feedback framework, exploring human structure and functions in mechanism: control of body temperature health and illness using a systems approac Positive feedback mechanisms There are only a few of these amplifier or cascade systems in the body. In positive feedback mechanisms, the stimulus progressively increases the response, so that as long as Table 1.1 Survival needs and related body activities the stimulus is continued the response is progressively Survival need Body activities saing amplified. Examples include blood clotting and uterine contractions during labour Communication Transport systems: blood During labour, contractions of the uterus are stimu circulatory system, lymphatic lated by the hormone oxytocin. These force the babys system head into the cervix of the uterus stimulating stretch nternal communication: nervous receptors there. In response to this, more of the hormone system, endocrine system External communication: special oxytocin is released, further strengthening the contrac enses, verbal and non- verbal tions and maintaining labour. After the baby is born the stimulus (stretching of the cervix) is no longer present and the release of oxytocin stops(see Fig 9.5, P. 219) Intake of raw materials Intake of oxygen and elimination of waste Dietary intake Elimination of waste: carbon dioxide, urine, faeces Homeostatic imbalance Protection and survival Protection against the external This arises when the fine control of a factor in the internal environment:skin environment is inadequate and the level of the factor falls Resistance and immunity: outside the normal range. If control cannot achieve non-specific and specific defence homeostasis, an abnormal state develops that may mechanisms Body movement threaten health, or even life. Many of these situations are Reproduction explained in later chaptersIntroduction to the human body 7_ SURVIVAL NEEDS OF THE BODY Figure 1.4 Example of a physiological negative feedback mechanism: control of body temperature. Learning outcomes After studying this section you should be able to: • describe the role of the body transport systems • outline the roles of the nervous and endocrine systems in internal communication • outline how raw materials are absorbed by the body • state the waste materials eliminated from the body • outline activities undertaken by an individual for protection and survival. By convention, the body systems are described sepa￾rately in the study of anatomy and physiology, but in reality they are all interdependent. This section provides an introduction to body activities linking them to sur￾vival needs (Table 1.1). The later chapters build on this framework, exploring human structure and functions in health and illness using a systems approach. Positive feedback mechanisms There are only a few of these amplifier or cascade systems in the body. In positive feedback mechanisms, the stimulus progressively increases the response, so that as long as the stimulus is continued the response is progressively being amplified. Examples include blood clotting and uterine contractions during labour. During labour, contractions of the uterus are stimu￾lated by the hormone oxytocin. These force the baby's head into the cervix of the uterus stimulating stretch receptors there. In response to this, more of the hormone oxytocin is released, further strengthening the contrac￾tions and maintaining labour. After the baby is born the stimulus (stretching of the cervix) is no longer present and the release of oxytocin stops (see Fig. 9.5, p. 219). Homeostatic imbalance This arises when the fine control of a factor in the internal environment is inadequate and the level of the factor falls outside the normal range. If control cannot achieve homeostasis, an abnormal state develops that may threaten health, or even life. Many of these situations are explained in later chapters. Table 1.1 Survival needs and related body activities Survival need Body activities Communication Intake of raw materials and elimination of waste Protection and survival Transport systems: blood, circulatory system, lymphatic system Internal communication: nervous system, endocrine system External communication: special senses, verbal and non-verbal communication Intake of oxygen Dietary intake Elimination of waste: carbon dioxide, urine, faeces Protection against the external environment: skin Resistance and immunity: non-specific and specific defence mechanisms Body movement Reproduction