Chapter 1 – Introduction to anatomy and physiology A new language
What knowledge should I bring to A&P course? Basic math – mean, fractions, percents, ratios, proportions, metric system, tables, graphs and charts Basic chemistry – matter, elements, atomic structure, chemical interactions, bonds, chemical reactions, molecules/macromolecules, Animal cell biology – membrane, organelles, cell cycle Microscopy Cell transport mechanisms – osmosis, diffusion and active transport Enzymes Scientific method and how to write lab report
Keep in mind Anatomy explains physiology Form and function are interrelated
Overview of Anatomy and Physiology Anatomy – the study of the structure of body parts and their relationships to one another Gross or macroscopic – large visible body structures (heart, lungs, kidney etc.) Different ways to approach gross anatomy: Regional – study of all the structure in a particular region of the body (leg, abdomen etc.) Systemic – study a particular system at a time. Microscopic – deals with structures that are too small to be seen with the naked eye Cytology – relates to the cells Histology – study of the tissues Physiology – the study of the function of the body
Specialized Branches of Anatomy Pathological anatomy – study of structural changes caused by disease Radiographic anatomy – study of internal structures visualized by specialized scanning procedures such as X-ray, MRI, and CT scans Molecular biology – study of anatomical structures at a subcellular level
Anatomical Position Body erect feet slightly apart palms facing forward thumbs point away from body
The new language – anatomical position The anatomical position is extremely important in studying anatomy since it is universal. This allows professionals to easily communicate with each other, even if they are from different countries or backgrounds Regardless of the patient body position – you ALWAYS refer to anatomical position
Other concepts you need to know if you want to speak the language (you’ll do most of it in the lab) Body planes Dorsal and ventral cavities Abdominopelvic quadrants and 9 regions Organ systems Membranes
Systems covered in A&P I Integumentary – cover, protection, sweat, receptors Nervous system – control Skeletal system – support, protection, calcium, blood cells, movement Muscles - movement
Systems covered in A&P II Endocrine system – hormonal regulation Cardiovascular system Lymphatic system/immunity Respiratory system Digestive system Urinary system Reproductive system
Necessary Life Functions Maintaining boundaries – the internal environment remains distinct from the external environment Cellular level – accomplished by plasma membranes Organismal level – accomplished by the skin Movement – locomotion, propulsion (peristalsis), and contractility Responsiveness – ability to sense changes in the environment and respond to them Digestion – breakdown of ingested foods Metabolism – all the chemical reactions that occur in the body (we will study in details in A&P II)
Necessary Life Functions Excretion – removal of wastes from the body Reproduction – cellular and organismal levels Cellular – an original cell divides and produces two identical daughter cells Organismal – sperm and egg unite to make a whole new person Growth – increase in size of a body part or of the organism
Survival Needs Nutrients – needed for energy and cell building Oxygen – necessary for metabolic reactions Water – provides the necessary environment for chemical reactions (60-8% of body weight) Normal body temperature – necessary for chemical reactions to occur at life-sustaining rates (why is it important to maintain core body temperature?) Atmospheric pressure – required for proper breathing and gas exchange in the lungs
Homeostasis Homeo – unchanging + stasis – standing The ability to maintain a relatively stable internal environment in an ever-changing outside world The internal environment of the body is in a dynamic state of equilibrium – it is not a precise value Homeostatic regulation is the adjustment of physiological systems to preserve homeostasis It happens in an environment that is inconsistent, unpredictable and at times – dangerous Failure to maintain homeostasis can lead to illness or even death
Homeostatic control Homeostasis is a continuous process that uses physiological control system to monitor key functions Some aspects of control systems: Nervous system – coordinates and integrates conditions that are compatible with normal functions: blood volume, blood osmolarity, blood pressure, body temperature etc. Tonic control – maintaining “moderate activity” – example – blood vessel diameter. Tonic control is not stopping or starting activity (similar to turning radio volume louder or softer) Antagonistic control – for systems that are not under tonic control either by hormones or the nervous system (insulin and glucagon, sympathetic and parasympathetic)
Local and long-distance control pathways Local control – in the cell or tissue – autocrine or paracrine mechanisms (CO 2 levels in the tissue influence diameter of local capillaries) Long distance control involves the nervous and endocrine systems. The long distance control involves 3 components – sensor, integration center and effector
Homeostatic Control Mechanisms components Variables produce a change in the body The three interdependent components of control mechanisms: Receptor – monitors the environments and responds to changes (stimuli) Control center – determines the set point at which the variable is maintained Effector – provides the means to respond to stimuli
Define Negative Feedback In negative feedback systems, the output shuts off the original stimulus
Positive Feedback In positive feedback systems, the output enhances or exaggerates the original stimulus Example: Regulation of blood clotting Positive feedback is also known as a “vicious cycle” – if not stopped can lead to death Figure 1.6
Some environments in our body – fluid compartments Fluids in the body are compose of water and solutes There are 2 distinct fluid compartments Intracellular fluid (ICF) The cytosol of cells Makes up about two-thirds of the total body water Extracellular fluid (ECF) Major components include the interstitial fluid, plasma and lymph Minor components include all other extracellular fluids (water in dense CT, bone, fluid between visceral and parietal membranes etc.)
Important components and characteristics of ECF* Normal rangeApproximate short-term nonlethal limit units Oxygen mmHg Carbon dioxide mmHg Sodium ions mmol/L Potassium ions mmol/L Calcium ions mmol/L Chloride ions mmol/L Bicarbonate ions mmol/L Glucose Mg/dl Body temperature (37.0) ( ) 0 F ( 0 C) Acid-base pH Medical Physiology – Guyton and Hall, 11 th ed.