General Physiology Introduction PDF

GENERAL PHYSIOLOGY INTRODUCTION By Asmaa Abd El-latef Seddek Lecturer of physiology Faculty of medicine Suez canal university  OBJECTIVES What is physiology? A review of organ systems The concept of homeostasis And feed...

GENERAL PHYSIOLOGY INTRODUCTION By Asmaa Abd El-latef Seddek Lecturer of physiology Faculty of medicine Suez canal university  OBJECTIVES What is physiology? A review of organ systems The concept of homeostasis And feed back control Body fluid compartments Introduction to the cell  PHYSIOLOGY (from the Greek physis = nature; logos = study) is the study of biological function—of how the body works, from cell to tissue, tissue to organ, organ to system, and of how the organism as a whole accomplishes particular tasks essential for life. Organ systems of the body have been divide in to four categories Support, Movement, and Protection  The integumentary system Includes the skin and accessory organs, such as the hair, nails, sweat glands, and sebaceous glands. THE SKELETAL SYSTEM AND THE MUSCULAR SYSTEM GIVE THE BODY SUPPORT AND ARE INVOLVED IN THE ABILITY OF THE BODY AND ITS PARTS TO MOVE. Integration and Coordination  The nervous system, consists of the brain, spinal cord, and associated nerves. The nerves conduct nerve impulses from the sense organs to the brain and spinal cord. They also conduct nerve impulses from the brain and spinal cord to the muscles and glands.  The sense organs, provide us with information about the outside environment is then processed by the brain and spinal cord, and the individual responds to environmental stimuli through the muscular system  The endocrine system, consists of the hormonal glands that secrete chemicals that serve as messengers between body parts Maintenance of the body  The cardiovascular system, consists of the heart and the blood vessels that carry blood through the body. Blood transports nutrients and oxygen to the cells, and removes waste molecules to be excreted from the body.  Blood also contains cells produced by the lymphatic system.  The respiratory system,, consists of the lungs and the tubes that take air to and from the lungs. respiratory system brings oxygen into the lungs and takes carbon dioxide out of the lungs Maintenance of the body cont,  The digestive system consists of the mouth, esophagus, stomach, small intestine, and large intestine (colon), along with the accessory organs: teeth, tongue, salivary glands, liver, gallbladder, and pancreas. This system receives food and digests it into nutrient molecules, which can enter the cells of the body  The urinary system, contains the kidneys and the urinary bladder. This system rids the body of nitrogenous wastes and helps regulate the fluid level and chemical content of the blood. Reproduction and Development  The male and female reproductive systems, discussed in contain different organs. The male reproductive system consists of the testes, other glands, and various ducts that conduct semen to and through the penis.  The female reproductive system consists of the ovaries, uterine tubes, uterus, vagina, and external genitalia. Both systems produce sex cells, but in addition, the female system receives the sex cells of the male and also nourishes and protects the fetus until the time of birth.  HOMEOSTASIS AND FEEDBACK CONTROL  Homeostasis describe the maintenance of nearly constant conditions in the internal environment  Home ( internal environment ) , stasis ( constant)  For example, the lungs provide oxygen to the extracellular fluid to replenish the oxygen used by the cells, the kidneys maintain constant ion concentrations, and the gastrointestinal system provides nutrients. NEGATIVE FEEDBACK A homeostatic mechanism that keeps a variable close to a particular value, or set point. It has three components: a sensor, regulatory center, and an effector. The sensor detects a change in the internal environment; the regulatory center activates the effector; the effector reverses the change and brings conditions back to normal again. Now, the sensor is no longer activated POSITIVE FEEDBACK  A mechanism that brings greater change in the same direction. A positive feedback mechanism can be harmful, as when a fever causes metabolic changes that push the fever still higher. Death occurs at a body temperature of 45°C because cellular proteins denature at this temperature and metabolism stops  Still, positive feedback loops such as those involved in blood clotting, the stomach’s digestion of protein, and childbirth assist the body in completing a process that has a definite cutoff point. BODY-FLUID COMPARTMENTS Tissues, organs, and systems can all be divided into two major parts, or compartments.  The intracellular compartment is that part inside the cells;  the extracellular compartment is that part outside the cells. Both compartments consist primarily of water they are said to be aqueous. The two compartments are separated by the cell membrane surrounding each cell. CELL STRUCTURE AND FUNCTION  Gives form( shape ) to the cell  Controls passage of materials into and out of the cell The main function of the cell nucleus is to control gene expression and mediate replication of dna during the cell division. it controls the hereditary characteristics of an organism. responsible for protein synthesis, cell division, growth, and differentiation. storage of hereditary material, genes in the form of dna (deoxyribonucleic acid) strands, referred to as chromatin.  Releases energy from food molecules formation of ATP(adenosine triphosphate) Smooth(a granular): metabolize compounds , stores Ca2 in muscles Rough (granular): assists in protein synthesis Synthesis of carbohydrates , packing of molecules , secreting lipids and glycoproteins  Digest foreign molecules , worms and damaged organisms The cytoplasm is the fluid that occupies and fills the space inside a cell. It contains and holds the various organelles of the cell in place.