Physiology

Animal organs are usually composed of more than one cell type. Each organ typically performs a given function. The stomach is an organ composed of tissues that aid in the digestion of food. Most organs have functions in only one organ-system. The stomach is involved only in the digestion of food as part of the digestive system. Organ systems, such as the digestive system, are collections of organs that perform a major function for the organism. Animal organ System & Homeostsis Animal Physiology

Homeostasis: is a term describe the physical and chemical parameters that an organism must maintain to allow proper functioning of its component cells, tissues, organs, and organ systems. Enzymes function best when within a certain range of temperature and pH, and that, cells must maintain a balance between having too much or too little water in relation to their external environment. Our body has a range of environmental (internal & external) parameters within which it works best. A.Multicellular organisms accomplish homeostasis by having organs and systems that coordinate their homeostasis by the help of the nervous system. B.Unicellular organisms accomplish homeostasis within a single cell by moving materials into and out of the cell by regulation of the cell membrane and its functioning. The maintenance of a stable internal environment. Homeostasis

Unicellular organisms such as paramecium, can dump wastes outside the cell by exocytosis. Multicellular organisms, such as a human, dump wastes outside cells then, carting away of these wastes outside the body is by both the circulatory and excretory system. Heat control is a major function of homeostatic conditions that involves the skin, muscular and nervous & circulatory systems. The ultimate control of homeostasis is accomplished by the nervous system (for rapid responses such as quick reflexes) and the endocrine system (for longer-term responses, such as maintaining the body levels of calcium). Homeostasis

Most physiological systems in the body use feedback to maintain the body's internal environment. Often this homeostatic control takes the form of two types of feedback cycles: I- Positive feedback control:Positive feedback control is used in some cases as input increases or accelerates the response. II- Negative feedback control mechanisms: is used by most of the body's systems, the information caused by the feedback causes a reverse response.Negative feedback control mechanisms Most physiological systems in the body use feedback to maintain the body's internal environment. Often this homeostatic control takes the form of two types of feedback cycles: I- Positive feedback control:Positive feedback control is used in some cases as input increases or accelerates the response. II- Negative feedback control mechanisms: is used by most of the body's systems, the information caused by the feedback causes a reverse response.Negative feedback control mechanisms Biological Feedback Positive feedback: Causes an amplification of the stimulus by the reaction. Negative feedback: Turns off the stimulus that caused it in the first place Feedback Systems in Homeostasis

Concentration of O 2 and CO 2 pH of the internal environment Concentration of nutrients and waste products Concentration of nutrients and waste products Concentration of salts Volume and pressure of Extra-cellular fluid Volume and pressure of Extra-cellular fluid  Plasma of the blood.  The extra-cellular fluid that  surrounds cells  The extra-cellular fluid that  surrounds cells Internal environment Internal components Parameters of homeostasis homeostasis Homeostasis

A.Extrinsic control: Most homeostatic systems are extrinsic: they are controlled from outside the body. For example: I.The nervous system: depends on sensors in the skin or sensory organs to receive stimuli and transmit a message to the spinal cord or brain. Signal is sent to an effector system, such as muscles or glands, that effects the response to the stimulus.spinal cord II.The endocrine system: involves hormones. Sensors detect a change within the body and send a message to an endocrine effector (parathyroid), which release hormones into the blood when blood minerals levels are low resulting in raising the blood minerals levels. B.Intrinsic control: Local controls usually involve only one organ or tissue. When muscles use more O 2, and also produce more CO 2, intrinsic controls cause dilation of the blood vessels allowing more blood into those active areas of the muscles. Eventually the vessels will return to "normal". Control Systems of homeostasis

A.Muscular System: (facilitates movement and locomotion); The muscular system produces body movements and body heat. B.Skeletal System: provides support and protection, and attachment points for muscles. The skeletal system provides rigid framework for movement. It supports and protects the body and body parts, produces blood cells, and stores minerals. C.Skin or Integument: (the outermost protective layer); It prevents water loss and protect the body from invasion of foreign microorganisms and viruses. D.Respiratory System: moves O 2 from the external environment into the internal environment; also removes CO 2. This occurs by exchanging gas between lungs and the blood. It also maintains pH of the blood and facilitates exchange of CO 2 and O 2. Body Systems and Homeostasis

E.Circulatory System: transports O 2, CO 2, nutrients, waste products, immune components, and hormones via the heart, capillaries, arteries, and veins. The lymphatic system also transports excess fluids to and from circulatory system and transports fat to the heart. F.Immune System: defends the internal environment from invading microorganisms and viruses. It provides cells that aid in protection of the body from disease by the antigen/antibody response. G.Excretory System: regulates volume of internal body fluids as well as eliminates metabolic wastes from the internal environment. it removes organic wastes from the blood. These wastes are then removed as urine. It is also responsible for maintaining fluid levels. Body Systems and Homeostasis

H.Nervous System: coordinates and controls actions of internal organs and body systems. Memory, learning, and conscious thought are the functions of the nervous system. Maintaining autonomic functions such as heartbeat, breathing, control of involuntary muscle actions. I.Endocrine System: works with the nervous system to control the activity of internal organs. it secretes hormones that regulate body metabolism, growth, and reproduction. Its organs communicate by chemical messages (hormones). J.Reproductive System: is mostly controlled by the endocrine system, and is responsible for survival and perpetuation of the species. Organs of this system produce gametes that combine in the female system to produce the next generation (embryo). Body Systems and Homeostasis

The Summary Control Systems of homeostasis Extrinsic control nervous system endocrine system Intrinsic control Muscular System Skeletal System Skin or Integument Respiratory System Circulatory System Immune System Excretory System Nervous System Endocrine System Reproductive System