Introduction to Physiology and Pathophysiology MDC305 PDF

Physiology and Pathophysiology Code: MDC305  Introduction to Physiology  Human physiology is the science of studying the physiological functions in human body  On different levels from – Cell to tissue, – Tissue to organ, – Organ to system, and of – How the organism...

Physiology and Pathophysiology Code: MDC305  Introduction to Physiology  Human physiology is the science of studying the physiological functions in human body  On different levels from – Cell to tissue, – Tissue to organ, – Organ to system, and of – How the organism as a whole does particular tasks essential for life.  Physiology derived from two Greek words – physis = nature; logos = study Body composition Levels of Structural Organization Cell Structure and Function Power house of cell  Metabolism All the chemical processes that take place in the organelles of the cells  Anabolism The use of energy for producing chemical substances(e.g. glycogen synthesis from glucose, protein from amino acids)  Catabolism The break down of complex, big molecules into smaller ones, mostly yielding energy (e.g. glycogenolysis… breakdown of glycogen to glucose, protein to amino acids) How Substances Enter and Leave the Cell Levels of Structural Organization Overview of Organ Systems 1. Integumentary 7. Lymphatic 2. Skeletal 8. Respiratory 3. Muscular 9. Digestive 4. Nervous 10.Urinary 5. Endocrine 11.Reproductive 6. Cardiovascular IntegumentaryHair System (integument Skin (skin) and Nails structures derived from it (hair, nails, and oil sweat glands) 1. Forms the external body covering 2. Protects the body 3. Regulates body temperature, eliminates wastes, and receives certain stimuli (tactile, temperature, and pain) Skeletal System (bone, cartilage, ligaments and joints) 1. Provides body support and protection 2. Permits movement 3. Produces blood cells (hematopoiesis) 4. Stores minerals. Muscular System (skeletal muscles) Skeletal muscles 1. Affects body movements 2. Maintains posture, and produces body heat.  Brain Nervous System (brain, spinal cord, peripheral nerves and sense organs) 1. Detects and responds to changes in internal and external environments 2. Enables reasoning and Nerves Spinal cord memory, and regulates body activities.  Pineal gland Endocrine SystemPituitary Thyroid gland gland 1. Controls and integrates Thymus body functions Adrenal such as growth,gland reproduction, Pancreas and nutrient use (metabolism) via Testis hormones secreted into the bloodstream Cardiovascular System (heart, blood vessels) 1. Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. 2. The heart pumps blood. Lymphatic System/Immunity Red bone (lymphatic vessels, marrow lymph Thymus nodes, and other lymphatic Lymphatic organs) vessels Thoracic duct 1. Houses white blood cells (lymphocytes) involved in Spleen immunity. 2. Removes foreign substances Lymph nodes and pathogens 3. Maintains tissue fluid balance through picking up fluid leaked from blood vessels and returning it to blood. Respiratory System (nose, pharynx, larynx, trachea, bronchi, lungs) 1. Supplies oxygen to the blood and eliminates carbon dioxide 2. Helps to regulate acid–base balance Pharynx is part of digestive and respiratory system Digestive system (mouth, pharynx, esophagus, stomach, small and large intestines, liver) 1. Mechanically and chemically breaks down foods for body use 2. Eliminates undigested wastes as feces Urinary System (kidneys, ureters, urinary bladder, urethra) 1. Removes various wastes from the blood 2. Regulates blood volume, and electrolyte balance 3. Helps to maintain the acid– base balance of the body. Reproductive systems Male: testes, penis, prostate gland and seminal vesicles Female: ovaries, uterus, vagina) 1. Production of sex hormones 2. Overall function is reproduction or production of offspring.  Digestive system Respiratory system Takes in nutrients, breaks them Takes in oxygen and down, and eliminates unabsorbed eliminates carbon dioxide matter (feces) Organ Systems Food O2 CO2 Cardiovascular system Interrelationships Via the blood, distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs All cells depend on organ Blood CO2 systems to meet their O2 survival needs. Urinary system Heart Eliminates Nutrients nitrogenous wastes and Organ systems work Interstitial fluid excess ions cooperatively to perform necessary life functions Nutrients and wastes pass between blood and cells via the interstitial fluid Integumentary system Feces Protects the body as a whole Urine from the external environment  Key Elements in Physiology Homeostasis  A state of balance among all the body systems needed for the body to survive and function correctly Communication and movement across cell membranes  Vital to integration & homeostasis  Cells communicate with other cells, tissues & organs  Homeostasis  Homeostasis homeo- (same) is the existence and maintenance of a relatively constant environment within the body despite fluctuations in either the external environment or the internal environment.  Homeostatic Regulation 1. Receptor 2. Afferent Pathway 3. Integrating or control center 4. Efferent Pathway 5. Effector The signal sent by the effector is called feedback, can be either negative or positive  Negative feedback: when the effector opposes the stimulus (such as a dropping temperature) and reverses the direction of change (causing the temperature to rise). Same with blood pressure and glucose level)  Positive feedback: when the effector reinforces the stimulus (such as uterine contractions during childbirth, which trigger the release of the hormone oxytocin) and amplifies the direction of change (causing even greater contractions and further release of oxytocin). Same with blood clotting) Negative Feedback – Temp Regulation Positive Feedback during childbirth  Pathophysiology  It is the study of disordered physiological processes that cause, result from, or are associated with a disease or injury  Causes of Cell Injury  Oxygen deprivation (hypoxia or ischemia)  Physical Agents (trauma)  Chemical agents and Drugs  Infectious Agents  Immunologic Reactions  Genetic Derangements  Nutritional Imbalances Cellular Adaptation to Injury or Stress Injury or Stress Adaptation Increased stimulation Hyperplasia or hypertrophy Decreased stimulation or Atrophy lack of nutrients Chronic irritation Metaplasia Hypertrophy:  increased in size due to increase in size of cells (may be physiologic such as increased workload increases skeletal muscle size or pathologic such as cardiac hypertrophy) Hyperplasia:  increased organ size due to increase in number of cells (may be physiologic such as female breast; puberty and pregnancy or pathologic such as prostatic hyperplasia) Atrophy:  Reduction of size due to a decrease in cell size and number may be physiologic atrophy such as post partum uterus or pathologic such as muscle atrophy due to denervation Metaplasia:  reversible change in which one differentiated cell type is replaced by another cell type. Usually occurs in response to chronic irritation e.g. myositis ossificans: repeated skeletal muscle injury- muscle replaced by bone  Cell Injury and Death  Irreversibleinjury: two types of cell death Necrosis: always pathologic Apoptosis: may be physiologic or pathologic  General Characteristics NECROSIS APOPTOSIS “Not programmed” “Programmed” Usually affects large areas of Usually affects scattered individual contiguous cells cells Cells and organelles swell Cells contract Control of intracellular environment is Control of intracellular environment is lost, cells rupture and spill contents maintained, cytoplasm packaged as “apoptotic bodies” INDUCES INFLAMMATION DOES NOT INDUCE INFLAMMATION Necrosis vs. Apoptosis  Inflammation  Response to injury (including infection) Types of Inflammation  Acute inflammation  Chronic inflammation – Short duration – Longer duration – Edema – Lymphocytes & – Mainly neutrophils macrophages predominate – Fibrosis – New blood vessels (angiogenesis) Types of Inflammation: acute vs. chronic Types of healing: resolution vs. fibrosis