Introduction to Physiology Lecture 1 PDF

Tishk International University Faculty of Nursing Introduction to Physiology Lecture - 1 1st Grade – Spring Semester 2023-2024 Lecture Objectives 1. Define Physiology and its purpose 2. Identify the fluids within the human body 3. Explain the importance of extracellular fluid 4. Identify the importa...

Tishk International University Faculty of Nursing Introduction to Physiology Lecture - 1 1st Grade – Spring Semester 2023-2024 Lecture Objectives 1. Define Physiology and its purpose 2. Identify the fluids within the human body 3. Explain the importance of extracellular fluid 4. Identify the importance of the “internal environment” in maintaining homeostasis. 5. Explain general physiology of Blood. Physiology Physiology: Is the sub-discipline of biology that explains the physical and chemical factors that control the origin, development, and progression of life. Physiology: Is the scientific study of functions and mechanisms in a living system. The word physiology comes from ancient Greek (physis) 'nature, origin', and (-logia) 'study of‘. Physiology Divisions of physiology: cellular physiology, viral physiology, bacterial physiology, plant physiology, human physiology and more subdivisions. Human Physiology: The field of study that explains the specific mechanisms and characteristics of the human body that make it a living being. Cells As The Living Units of The Body Cell is the basic living unit of the body. Each type of cell is adapted to perform one or a few specific functions. For example: 25 trillion red blood cells within each human being, transport oxygen from the lungs to the tissues. RBCs are the most abundant of any single type of cells in the body. The entire body has about 100 trillion cells. Cells As The Living Units of The Body Although the functions of cells are different, they have certain similar characteristics. In all cells: 1. Oxygen reacts with carbohydrate, fat, and protein to produce energy for cell function. 2. Chemical mechanisms for changing nutrients into energy are the same. 3. End products of their chemical reactions are transported to the surrounding fluid. Structure and Function The structure and function of body parts are closely related The structure of a part of the body allows performance of its functions Examples: 1. Bones of the skull provide protection for the brain. 2. Thin air sacs of the lungs permit movement of oxygen. Extracellular Fluid-The “Internal Environment” Body Fluids ~60% Body weight Intracellular 2/3 Extracellular “Internal Environment” 1/3 Interstitial fluid Potassium, magnesium, & phosphate ions Plasma F. Ions (sodium, chloride, and bicarbonate) Nutrients (oxygen, glucose, fatty acids, and amino acids Waste & CO2 Extracellular Fluid-The “Internal Environment” Ions and nutrients needed by the cells are located in the extracellular fluid. The extracellular fluid is called the internal environment, since all cells live in the same environment. Extracellular fluid is in continuous movement The intracellular fluid differs largely from the extracellular fluid Extracellular Fluid-The “Internal Environment” Fluid Compartments in the Human Body: The intracellular fluid (ICF) is the fluid within cells. The interstitial fluid (IF) is part of the extracellular fluid (ECF) between the cells. Blood plasma is the second part of the ECF. Materials travel between cells and the plasma in capillaries through the IF. Most of the water in the body is intracellular fluid. The second largest volume is the interstitial fluid, which surrounds cells that are not blood cells. A Pie Graph Showing the Proportion of Total Body Fluid in Each of the Body’s Fluid Compartments Extracellular Fluid Body Location mabast lamada shwene shlakane daraway xanaya 1. 2. 3. 4. 5. Blood Plasma ECF within blood vessels Lymph ECF within lymphatic vessels Cerebrospinal fluid (CSF) ECF in the brain and spinal cord Synovial fluid ECF in joints Aqueous humor and vitreous body ECF in eyes Water Content of the Body’s Organs and Tissues: Water content varies in different body organs and tissues, from as little as 8 percent in the teeth to as much as 85 percent in the brain. Homeostasis Maintenance of nearly constant conditions in the internal environment. Homoios and Stasis from Greek, "similar" and stasis, "standing still“ "staying the same". Equilibrium All organs perform their functions to maintain homeostasis: Lung O2 Gastrointestinal system nutrients Kidneys maintaining ion concentrations Extracellular Fluid Transport and Mixing SystemThe Blood Circulatory System Extracellular fluid is transported through all parts of the body in Two Stages: 1. The first stage is movement of blood through the body in the blood vessels. 2. The second stage is movement of fluid between the blood capillaries and the intercellular spaces between the tissue cells. General organization of the circulatory system. Diffusion of fluid and dissolved constituents through the capillary walls and through the interstitial spaces. Physiology of Blood BLOOD Blood is a fluid connective tissue. It circulate continually around the body, allowing constant communication between tissues distant from each other.  Fluid of life  Fluid of growth  Fluid of health Physical Characteristics of Blood Thicker than water 8 % of total body weight Blood volume »70 mL/kg of body weight »5 - 6 liters in males »4 - 5 liters in females Temperature - 100.40F pH - 7.35 to 7.45 Blood Functions 1. Respiratory  Transport O2 from lungs to tissues  Transport CO2 from tissues to lungs 2. Nutrition  Transport “food” from gut to tissues 3. Excretory  Transport waste from tissues to kidney (urea, uric acid) 4. Protective  White blood cells , antibodies, antitoxins. Blood Functions 5. Regulatory regulate body temperature  regulate pH through buffers  coolant properties of water Cooling water  vasodilatation of surface vessels dump heat Vasodilation vessels to dump heat  regulate water content of cells by interactions with dissolved ions and proteins regulate water of cells by react with ions and proteins 6. Body Temperature  Water- high heat capacity, thermal conductivity, heat of vaporization  Typical heat generation is 3000 kcal/day Blood composition  Suspension of cells in plasma (carrier fluid) 45% Cells 55% Plasma  Cells Red cells (erythrocytes) 5x106/mL White cells (leukocytes) 7x103/mL Platelets (thrombocytes) 3x105/mL Blood Plasma Straw colored clear liquid Contains 90% water 7% plasma proteins created in liver confined to bloodstream  albumin maintain blood osmotic pressure  immunoglobulins antibodies bind to foreign substances called antigens form antigen-antibody complexes  fibrinogen for clotting 2% other substances  Nutrients, electrolytes, gases, hormones, waste products Functions of plasma proteins 1. Coagulation of blood – Fibrinogen to fibrin 2. Defense mechanism of blood – Immunoglobulins 3. Transport mechanism – α Albumin, β globulin transport hormones, gases, enzymes, etc. 4. Maintenance of osmotic pressure in blood 5. Acid-base balance 6. Provides viscosity to blood 7. Provides suspension stability of RBC Formed Elements of Blood Red blood cells (R.B.C.) White blood cells (W.B.C.)  granular leukocytes  neutrophils (60-70%)  eosinophils (1-4%)  basophils (1%)  agranular leukocytes  lymphocytes - T cells, B cells, natural killer cells (N.K.C) (20-40%)  monocytes (3-10%) Platelets (special cell fragments) Functions of RBC 1. Transport oxygen from lungs to the tissues (oxyhemoglobin). 2. Transport carbon-di-oxide from tissues to lungs (carboxyhemoglobin) 3. Hemoglobin acts as a buffer and regulates the hydrogen ion concentration (acid base balance) 4. Carry the blood group antigens and Rh factor Functions of neutrophils 1. First line of defense against invading micro-organisms. 2. Powerful and effective killer machine – contains enzymes like protease, elastase, metalloproteinase, NADPH oxidase; antibody like substances called defensins. Defensins – antimicrobial peptides active against bacteria and fungi. 3.Secrete Platelet Aggregation Factor (PAF) – accelerates the aggregation of platelet during injury to the blood vessels Functions of eosinophils Secrete lethal substances at the time of exposure to foreign proteins/parasites 1. Eosinophil peroxidase – destroy worms, bacteria and tumor cells. 2. Major basic protein – damage parasites 3. Eosinophil cationic protein (ECP)- destroys helminths. 4. Eosinophils derived neurotoxin – destroys nerve fibers (myelinated nerve fibres) Functions of basophils Basophil granules release some important substances like – 1. Histamine – Acute hypersensitivity reaction- vascular changes, increase capillary permeability 2. Heparin – prevents intravascular blood clotting 3. Hyaluronic acid – necessary for deposition of ground substances in basement membrane Overplayed 4. Proteases – exaggerate inflammation Basophil have IgE receptor – hypersensitivity reaction Functions of Platelets 1. Blood clotting 2. Clot retraction 3. Defense mechanism 4. Homeostasis 5. Repair of blood vessel