Physiology Lecture 1: Organization of Human Body & Cell Plasma Membrane PDF

Instructor information department of physiology Academic hours : >…………….day :am >……………day : am Learning outcomes: By the end of this lecture you should be able to A. Know the organization of human body B. Explain the compartments of body fluids.. C. Discuss the structure...

Instructor information department of physiology Academic hours : >…………….day :am >……………day : am Learning outcomes: By the end of this lecture you should be able to A. Know the organization of human body B. Explain the compartments of body fluids.. C. Discuss the structure and functions of the cell membrane  Organization of Human Body -Physiology is the science that studies the functions of the normal living organs and how these functions interplay to maintain human existence and well being. 4 -Life is maintained by coordination of the functions of various systems. Organization of human body -The human body is made up of different systems e.g. digestive system, repiratory system and others whose functions are coordinated and integrated together. -Each system consists of many organs that made up of many tissues of complementary functions.  Systems Cells Tissues Organs -Each tissue consists of millions of similar cells. -The cell is the basic unit of structure and function in the body. -The cells consist of organelles as mitochondria and ribosomes each of them has a specific function. Summary of the main body systems 1-Nervous system 2-Cardiovascular system 3-Respiratory system 4-Lymphatic system 5-Musculo-skeletal system Summary of the main body systems 6-Digestive system 7-Endocrine system 8-Urinary system 9-Reproductive system 10-Immune system 1- Nervous system Consists of: - brain,spinal cord and nerves. Function: - collects and processes information from the senses via nerves and controls muscle actions. - it also controls most of other systems. 2- Cardiovascular system Consists of : heart and blood vessels. Functions: - circulates blood around the body via the heart, arteries and veins, delivering oxygen and nutrients to organs and cells and carrying their waste products away. 3- Respiratory system - Lungs, trachea and larynx. - Carries oxygen and removes carbon dioxide from the body. 4- Lymphatic system - lymph nodes and lymph vessels. - defends the body against disease-causing agents. 5-Musculo-skeletal system - Muscles and bone 1-Enables the body to move using muscles. 2-Bones supporting the body and its organs. 6-Digestive system - Mouth, oesphagus, stomach, small and large Intestine. - Digestive and absorptive processes that provide nutrients. 7-Endocrine system -Pituitary gland, thyroid gland, pancreas and adrenal gland. -Provides chemical communications within the body using hormones. 8- Urinary system - Kidney, urinary bladder and ureter. - Kidneys filter blood and remove wastes. 9-Reproductive system - Testes and ovary - Sex organs required for production of offspring. 10- Immune system - White blood cells. - Body defense against infections. Cell (Plasma) Membrane Cell (Plasma) Membrane Definition of cell membrane -It is a thin elastic semi-permeable membrane that surrounds the cell. -Semi-permeable means allowing some substances to pass through it and prevent others). -Its thickness is about 7.5 nm. (75 Ao = Angstrom = 10-10 of meter). Cell Intracellular fluid Extracellular fluid (ICF) (ECF) = cytoplasm Cell Functions of cell membrane  Functions of cell membrane 1- It separates the cytoplasm from ECF. 2- It maintains cell's internal environment 3- It controls distribution of ions e.g Na+, K+ into and out of the cell.  Functions of cell membrane 4-It contains receptors for hormones and transmitter substances. 5- It generates membrane potentials. Structure of the cell membrane - It is formed of 3 components: 1- Lipids 42%. 2- Proteins 55%. 3- Carbohydrates 3%. A) Lipids They form the basic structure of the membrane. -They include mainly phospholipids, cholesterol, and glycolipids. -Phospholipids are arranged into 2 layers → lipid bilayer. Phospholipids molecules -Phospholipids molecules, consist of: 1- Heads: - relatively hydrophilic (H2O soluble). - face the ICF and ECF sides. 2- Tails: - relatively hydrophobic (H2O insoluble). - face each other in the interior of bilayer. Membrane phospholipids Hydrophilic heads PO4- Hydrophobic tails F.A  ECF Bilayer Hydrophobic area ICF Cholesterol B) Types of Proteins Intrinsic or integral Extrensic or peripheral protein protein bind to hydrophobic bind to hydrophilic area of lipid bilayer heads or intrinsic pt. Include 2 types: they bind either : 1-Transmembrane pt. 1-extracellular surface. 2-occupy ½ thickness 2-intracellular surface. of membrane.  1)Types of intrinsic proteins 1-Transmembrane protein Functions a.Channels → for diffusion of small sub. b.Carriers → for transports materials c.Pumps → actively transport ions d.Receptors → fo r hormones Transmembrane protein may act as: 1) Channel 2) Receptor 3) Carrier 4) Pump enzyme Bilayer Cholesterol  Signal Enzymes Receptor ATP Transport Enzymatic activity Signal transduction  1) Types of intrinsic Proteins 2- present on one side of memb. Functions act as enzymes that activate or inactive metabolic processes. 2) Types of peipheral Proteins i) bind to the intracellular surface of the membrane → cyto-skeleton. ii) bind to the extracellular surface of the membrane →glycocalyx (cell coat).  1) Types of intrinsic Proteins 2- present on one side of memb. Functions act as enzymes that activate or inactive metabolic processes. 2) Types of peipheral Proteins i) bind to the intracellular surface of the membrane → cyto-skeleton. ii) bind to the extracellular surface of the membrane →glycocalyx (cell coat). References 1-Ganong's review of medical physiology, 23rd Edition 2. Guyton & Hall textbook of medical physiology 12th edition. 3. Medical physiology, 4- principles for clinical medicine, 4th edition. THANKS