Week 2(1) - Levels of structural organisation and Homeostasis PDF

Week 2; Session 1 Human Anatomy & Physiology - 2 (HMG381) Structural Organization & Homeostasis Dr. Merin Thomas [email protected] Office hours : Tuesday & Thursday – 1.00pm to 3.00pm Learning Objectives Levels of structural organization Homeostasis Homeostatic Imbalances Levels of Structura...

Week 2; Session 1 Human Anatomy & Physiology - 2 (HMG381) Structural Organization & Homeostasis Dr. Merin Thomas [email protected] Office hours : Tuesday & Thursday – 1.00pm to 3.00pm Learning Objectives Levels of structural organization Homeostasis Homeostatic Imbalances Levels of Structural Organization CHEMICAL LEVEL ATOMS & MOLECULES CELLULAR LEVEL CELLS 6 TISSUE LEVEL TISSUE ORGAN LEVEL ORGAN ORGAN SYSTEM LEVEL ORGAN SYSTEM ORGANISM LEVEL ORGANISM Levels of Structural Organization - LEVEL 1 - CHEMICAL LEVEL Cells are composed of water, inorganic ions, and carboncontaining (organic) molecules. Water - 70% of the cell Organic molecules - carbohydrates, lipids, proteins, and nucleic acids Inorganic ions - sodium (Na ), potassium (K ), magnesium + + (Mg ), calcium (Ca ), phosphate (HPO ), chloride (Cl ), and 2+ 2+ 42- - bicarbonate (HCO ), constitute 1% or less of the cell mass. 3- Levels of Structural Organization LEVEL 1 - CHEMICAL LEVEL There are four sub-levels 1.Subatomic level 2. Atomic level 3. Molecular level 4. Macromolecular level Levels of Structural Organization LEVEL 1 - CHEMICAL LEVEL 1.Subatomic level : It consists of subatomic particles, i.e., protons, electrons and neutrons Levels of Structural Organization LEVEL 1 - CHEMICAL LEVEL 2. Atomic level : A basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons The smallest part of a chemical element that can take part in a reaction. Levels of Structural Organization LEVEL 1 - CHEMICAL LEVEL 3. Molecular level: A molecule is an electrically neutral group of two or more atoms held together by covalent chemical bonds Levels of Structural Organization LEVEL 1 - CHEMICAL LEVEL 4. Macromolecular level: Polymers by the union of several molecules (e.g.: proteins, nucleic acids). The binding of various macromolecules are macromolecular associations (e.g.: glycoproteins, chromatin). These associations constitute the boundary between the biotic and abiotic. For example, nucleic acids have the ability to selfreplicate. Levels of Structural Organization - LEVEL 2 - CELLULAR LEVEL A variety of molecules combine to form the fluid and organelles of a body cell. Cells are the basic structural and functional units of an organism that are composed of chemicals A cell is the smallest independently functioning unit of a living organism. All living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells. Levels of Structural Organization - LEVEL 2 - CELLULAR LEVEL A human cell, such as a smooth muscle cell, typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid together with a variety of tiny functioning units called organelles. Levels of Structural Organization - LEVEL 3 - TISSUE LEVEL Groups of cells and materials surrounding them come together to form Tissues. FOUR main types of tissues 1. Epithelial Tissue 2. Connective Tissue 3. Nervous Tissue 4. Muscular Tissue Levels of Structural Organization - LEVEL 4 - ORGAN LEVEL Levels of Structural Organization - LEVEL 4 - ORGAN LEVEL Organs are structures that are composed of two or more different types of tissues; they have specific functions and usually have recognizable shapes. VITAL ORGANS - Essential for life; if any one of these organs do not function, it can result in death Levels of Structural Organization - LEVEL 5 - ORGAN SYSTEM LEVEL An organ system consists of related organs with a common function Levels of Structural Organization - LEVEL 6 - ORGANISM LEVEL All the parts of the human body functioning together constitute the total organism. From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 3 HOMEOSTASIS Self-regulating process by which biological systems maintain stability while adjusting to changing external conditions. Homeostasis is a dynamic condition. In response to changing conditions, the body’s parameters can shift among points in a narrow range that is compatible with maintaining life. Homeostasis in the human body is continually being disturbed. Some disruptions - external - in the form of physical changes such as the intense heat of a hot summer day Other disruptions - internal- blood glucose level that falls when you skip breakfast HOMEOSTASIS The body can regulate its internal environment through many feedback systems. A feedback system or, feedback loop, is a cycle of events in which the status of a body condition is monitored, evaluated, changed, re-monitored, re-evaluated etc. HOMEOSTASIS A feedback system includes three basic components: body temperature, blood pressure, blood glucose level 1. A receptor - body structure that monitors changes in a controlled condition and sends input to a control center, input sent as chemical signals or nerve impulses. 2. A control center - in our body the brain, has a ‘range’ within which a controlled condition should be maintained, evaluates the input it receives from receptors, and generates output commands when they are needed. Output sent as nerve impulses, chemical signals, hormones etc 3. An effector - a body structure that receives output from the control center and produces a response or effect that changes the controlled condition Any disruption that changes a controlled condition From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 11 HOMEOSTASIS In a feedback system, the response of the system “feeds back” information to change the controlled condition in some way, either negating it (negative feedback) or enhancing it (positive feedback). A negative feedback system reverses a change in a controlled condition. A positive feedback system tends to strengthen or reinforce a change in one of the body’s controlled conditions. If the response enhances or intensifies the stimulus, a system is operating by positive feedback. If the response reverses the stimulus, a system is operating by negative feedback. From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 13 HOMEOSTATIC IMBALANCES A fluctuation in the ability to maintain equilibrium and a constant environment within the body. As long as all of the body’s controlled conditions remain within certain narrow limits, body cells function efficiently, homeostasis is maintained, and the body stays healthy. If one or more components of the body lose their ability to contribute to homeostasis, the normal balance among all of the body’s processes may be disturbed. HOMEOSTATIC IMBALANCES If the homeostatic imbalance is moderate, a disorder or disease may occur; if it is severe, death may result. A disorder is any abnormality of structure or function. Disease is a more specific term for an illness characterized by a recognizable set of signs and symptoms. Diseases alter body structures and functions in characteristic ways. A person with a disease may experience symptoms, subjective changes in body functions that are not apparent to an observer. Examples of symptoms are headache, nausea, and anxiety. Objective changes that a health care professional can observe, or measure are called signs. Signs of disease can be either anatomical, such as swelling or a rash, or physiological, such as fever, high blood pressure, or paralysis. HOMEOSTATIC IMBALANCES Diabetes Graves' disease Hypothermia Hyperthermia Dehydration Hypertension Hemochromatosis Myocardial infarction (heart attack) Asthma Hemophilia Crohn's disease Anemia Multiple sclerosis Muscular dystrophy Signs & Symptoms Causes MAINTENANCE OF HOMEOSTASIS The maintenance of homeostasis in response to external as well as internal/physiological changes is an important factor for survival This results from the coordinated activities of all the different organ systems, ultimately controlled by the endocrine and nervous systems ACTIVITES & ASSIGNMENTS Quiz 1 On Wednesday, March 8th 2023 (22/66) & Thursday March 9th 2023 (33/77) Portions: Anatomical terminology, planes & regions, Biomedical Literature review, Levels of structural organization, Homeostasis, Interaction and Interdependence of organ systems, Maintenance of homeostasis (Weeks 1-3.1) Assignment Submission On Wednesday, 15th March 2023; 1.30pm (22/66) & Thursday March 16th 2023; 12.30pm (33/77) ACTIVITES & ASSIGNMENTS Any doubts regarding assignment? REFERENCES Tortora, Gerard J. And Bryan H Derrickson. Principles of Anatomy and Physiology. John Wiley & Sons, 2020 Standring, Susan. Gray’s Anatomy E-Book. Elsevier Health Sciences, 2015 Ulrich-Lai, Y. M., & Herman, J. P. (2009). Neural regulation of endocrine and autonomic stress responses. Nature reviews. Neuroscience, 10(6), 397–409. https://doi.org/10.1038/nrn2647