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.