Cell Physiology PDF

Introductory Concepts to Human Physiology By: Dr. Musa AbdulKarim Omoyine MBBS, FWACS, FMCOG Introductory Concepts to Human Physiology Learning objectives 1. To define Human Physiology 2. To highlight the key concept of Human Physiology. 3. To highlight the various subfields in Human Phys...

Introductory Concepts to Human Physiology By: Dr. Musa AbdulKarim Omoyine MBBS, FWACS, FMCOG Introductory Concepts to Human Physiology Learning objectives 1. To define Human Physiology 2. To highlight the key concept of Human Physiology. 3. To highlight the various subfields in Human Physiology 4. To highlight the relevance of human physiology in the field of medicine. 5. Conclusion Introductory Concepts to Human Physiology Definition  Human physiology is the study of the functions and processes that occur within the human body.  It is one of the subdivision of the vast field of physiology.  It explores how human body’s systems, organs, cells work together to maintain homeostasis or a stable internal environment. Introductory Concepts to Human Physiology Key concept of human physiology  Level of organization.  Integration.  Homeostasis.  Regulation.  Introductory Concepts to Human Physiology Level of organization  The human body is composed of cells, tissues, organs and systems that work together to maintain overall function.  Atomic→→Molecular→→Cellular→→Tissue→→Organ →→System →→Organism.  Cellular  Cell is the basic living unit of the body (100 trillion cells in the body out of which 25 trillion cells are red blood cells).  Each cell is adapted to carry out one or a few particular functions.  However all cells have some common basic characteristic e.g generation of energy from nutrients.  Almost all cells also have the ability to reproduce additional cell of their own kind. Introductory Concepts to Human Physiology Level of organization  Cellular  60% of adult human body is made up of fluid with 2/3 intracellular and 1/3 extracellular.  The extracellular fluid form the internal environment of the body.  All cells live in the same internal environment that contain nutrients and ions needed by the cells to maintain live and perform their function.  Introductory Concepts to Human Physiology Level of organization  Human body systems  Nervous system: Respond to external stimuli to protect the body. It is composed of three major parts: the sensory input portion, the central nervous system (or integrative portion), and the motor output portion.  Circulatory system: Transport blood to different parts of the body in two stages; first in blood vessels through the body and secondly movement of fluid between blood capillaries and intercellular spaces between the tissue cells.  Respiratory system: Pick oxygen from the atmosphere for body utilization and eliminate carbon dioxide as bye- product back into the atmosphere. Introductory Concepts to Human Physiology Level of organization  Human body systems  Digestive system: Break down food product into small utilizable units..  Endocrine system: Contain glands that secrete chemical substances called hormone that regulate many metabolic functions.  Renal system: Maintain fluid balance and eliminate waste products of metabolism Introductory Concepts to Human Physiology  Human body systems  Integumentary system: The skin and its various appendages, including the hair, nails, glands, and other structures, cover, cushion, and protect the deeper tissues and organs of the body and generally provide a boundary between the body’s internal environment and the outside world.  Musculoskeletal system: Provide motility for different part of the body and the whole body. Introductory Concepts to Human Physiology Integration  The coordination of different systems and processes to maintain homeostasis and overall health.  In the metabolism of protein:  Respiratory and digestive systems supply oxygen and amino acids respectively.  Circulatory system deliver to the site of metabolism and then deliver the waste product to the kidney for elimination. Introductory Concepts to Human Physiology Integration Introductory Concepts to Human Physiology Integration  Inter relationship between body systems  Nervous system and endocrine systems  Circulatory and respiratory systems  Digestive and urinary systems  Muscular and skeletal systems Introductory Concepts to Human Physiology Homeostasis  The ability to maintain a stable internal environment despite changes in external conditions. Introductory Concepts to Human Physiology Regulation  The mechanism that control and adjust the body’s functions to maintain homeostasis.  There are 3 main control mechanisms  Negative feedback control  Positive feedback control  Feedforward(Adaptive) control Introductory Concepts to Human Physiology Negative feedback  This is control mechanism that initiate response that is negative or opposite to the initial stimulus.  Most control systems of the body act by negative feedback.  Example of negative feedback include  A high concentration of carbon dioxide in the extracellular fluid stimulating respiratory centre that increases pulmonary ventilation which in turn, decreases the extracellular fluid carbon dioxide concentration because the lungs expire greater amounts of carbon dioxide from the body. Introductory Concepts to Human Physiology Positive feedback  This is control mechanism in which the initial stimulus initiate response that causes more of the same stimulus.  Positive feedback is also known as a “vicious cycle,” which can lead to instability and sometimes cause death.  However a mild degree of positive feedback can be overcome by the negative feedback control mechanisms of the body and the vicious cycle fails to develop. Introductory Concepts to Human Physiology Positive feedback  Examples of positive feedback include:  Pumping effectiveness of the heart when there is excessive bleeding. The heart become weak leading to reduce coronary blood supply further weakening the heart.  Childbirth in which uterine contractions pushes the baby’s head through the cervix. Stretch of the cervix sends signals through the uterine muscle back to the body of the uterus, causing even more powerful contractions until baby is born.  Introductory Concepts to Human Physiology Feedforward(Adaptive) control  Is a more complex control mechanism that operate like a delayed negative feedback.  For instance, some movements of the body occur so rapidly that there is not enough time for nerve signals to travel to the brain for coordination. Therefore, the brain uses a principle called feed- forward control to cause required muscle contractions. That is, sensory nerve signals from the moving parts apprise the brain whether the movement is performed correctly. If not, the brain corrects the feed-forward signals that it sends to the muscles the next time the movement is required. Introductory Concepts to Human Physiology Subfields  Neurophysiology: The study of nervous system and its functions.  Cardiovascular physiology: The study of heart, blood vessels and blood circulation.  Respiratory physiology: The study of lungs, breathing and gas exchange.  Renal physiology: The study of kidneys and their role in regulating body waste and waste removal.  Gastro-intestinal physiology  Endocrine physiology  Reproductive physiology Introductory Concepts to Human Physiology Relevance of human physiology in medicine  Health and wellness: Maintaining overall health and preventing disease e.g exercise, nutrition and stress management.  Medicine: Diagnosing and treating diseases and disorders e,g hypertension, diabetes etc.  Research: Advancing our knowledge of human biology and developing new Introductory Concepts to Human Physiology Conclusion  Human physiology is a complex and fascinating field that is essential in understanding human health and diseases.  Understanding human physiology can help us make informed decisions about our health and wellness.