Introduction to Anatomy and Physiology

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A Basic Understanding of the Form and Functions of the Human Body

…But First, a little language

• The language of anatomy ( a little Greek, a little Latin, a whole lot of Medical Terminology) – If you understand the root an prefix/suffix organization of the vocabulary of the human body, a lot less memorization and a lot more understanding will occur – Ex. Cyte means cell, anything that begins with hepat- refers to the liver, therefore without having to memorize I know a hepatocyte is a Liver cell – See handout 1, App 11 Stedman’s Medical Dictionary

Basic Concepts

• Anatomy = Form – Anatomy, Greek “cutting away”, refers to the study of structure of body parts and their relationships • What does it look like? What pieces does it have • Physiology = Function – Physiology, the study of life or function • What does it do? • Function follows form follows function… – “complementarity of structure and function” • Ex. Directionality of blood flow due to one way valves

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A Few More “Studies”

• Pathological Anatomy: the study of structural changes caused by disease • Developmental Anatomy: study of structural changes that occur througout life • Emryology: study of developmental changes before birth

Now Back to Anatomy…

Organization

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This organization applies to all animals and roughly to all life…

Levels of Structural Organization

• Chemical: atoms make up molecules make up organelles • Cellular: semi-permeable membrane containing cytoplasm and organelles made up of molecules made up of atoms – Cytology: study of the cell • Tissue: cosist of similar cell types plus extracellular material – Histology: study of tissues • Organ: discrete structures made up of tissues that carry out particular functions • Organ System: organs and supporting structures that work closely together to perform an area of bodily function • Organism: everything comes together… the complete living individual

11 Organ Systems

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Necessary Life Functions

• Maintenance of Boundaries: continuous skin in and out keeps internal environment separate from internal • Movement: locomotion, propulsion (peristalsis), contractility • Responsiveness: sense and respond to environmental changes and stimuli • Digestion: breakdown of food into usable parts

Life Functions 2

• Metabolism: all chemical reactions that occur within the body – Anabolism: build things – Catabolism: break things down • Excretion: removal of wastes from the body • Reproduction: cellular and organism • Growth: increase in size and number of cells leading to growth of a body part or of the organism

Survival Needs • Nutrients: • Water: 60-70% water – Intracellular (cytoplasm), extracellular, interstitial… • Oxygen: metabolic reactions • Maintaining Temperature: necessary for chemical reactions to sustain life • Atmospheric Pressure: breathing and gas exchange • Homeostasis of the internal environment (partially maintained by the previous needs)

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Homeostasis

Basics of Homeostasis • Homeostasis: dynamic equilibrium of the internal environment • Nervous and Endocrine systems drive, but everyone contributes • 3 Interdependent Components – Receptor: monitors and responds to the enviroment – Control Center: determines the set point at which variable is to be maintained; analyzes input; decides action – Effector: provides the means for the response to the stimuli • Results of the response then FEED BACK to influence the effect of the stimuli

Negative Feedback

• Reduce the effect of the stimuli so the process is shut off – Prevent sudden severe changes within the body – Heart rate, blood pressure, body temperature… • Most homeostatic mechanisms are Negative Feedback

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Negative Feedback Mechanism

Positive Feedback

• Enhance the effects of the stimuli so the process continues and increases in speed – “Positive” because the change occurs in the same direction as the initial changes; the variable further deviates from its original value – Not used to promote the daily well-being of the body, because they can race out of control • Control infrequent events that do not require continuous adjustments – Childbirth, blood clotting

Positive Feedback Mechanism

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Homeostatic Imbalance

• Disease • Natural Aging process – Control systems become less efficient – Internal environment becomes less stable • Feedback Mechanism Imbalance – Negative feedback system becomes overwhelmed and positive feedback mechanisms take over • Heart Failure

Tissues of the Body

3 Layers Become the 4 Tissues

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Epithelial Tissue - Covering

Where you find it…

Basics of Epithelial Tissue • Sheet of cells that covers a body surface or lines a body cavity – Covering and Lining: outer layer of skin, inner and outer lining of most organs and body cavities – Glandular: creates the glands; one or more cells that make and secrete an aqueous fluid • Barrier that most substances received by or given off from the body must pass through • Rest upon and supported by connective tissue • Avascular (no blood supply), but innervated (has supplied by nerve fibers) – Nourished by blood vessels in the underlying connective tissue

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Functions of Epithelial Tissue

• Protection • Absorption • Filtration • Excretion • Secretion • Sensory Reception

Connective Tissue - Support

Where to find it…

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Basics of Connective Tissue • Most Abundant and Widely distributed Tissue • Main Classes – Connective Tissue • Loose: Areolar, Adipose, Reticular • Dense: Dense Regular, Dense Irregular, Elastic – Cartilage: Hyaline, Elastic, Fibrocartilage – Bone Tissue – Blood • Functions – Binding and Support, Protection, Insulation, Transportation (blood)

Structural Elements • Ground Substance – Unstructured material that contains the fibers and fills the space bet ween cells • Fibers – provide support – Collagen: extremely tough, provide high tensile strength • White fibers – Elastic: rubber-like proteins allows them to stretch and recoil • Yellow fibers – Reticular: short, fine, collagenous fibers that are continuous with collagen fibers • Branch extensively forming delicate support networks

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Cell Types of Connective Tissue • Blast Cells: “forming”, “bud”, “sprout” – Each major class of connective tissue has a fundamental cell type that exists in mature and immature forms – Fibroblasts, Osteoblasts, Chondroblasts – Secrete ground substance and fibers of their particular matrix • Other Cell Types – Fat (adipose) Cells: storage – White Blood Cells: defend and fight against infections – Mast Cells: initiate local inflammatory response against foreign microorganisms (bacteria, fungi…) – Marcophages: phagocytize (eat) foreign material

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Coverings and Linings • Continuous multicellular sheets composed of at least 2 primary tissue types – Epithelium bound to underlying connective tissue proper • Cutaneous Membrane: skin – Organ system consisting of keratinized epithelium (epidermis) attached to a layer of dense irregular connective tissue (dermis) • Mucous Membranes: line body cavities that open to the exterior – Moist membranes bathed in secertions (or urine) • Serous Membranes: found in closed body cavities – Thin, clear serous fluid that lubricates the membranes and surrounding organs

Muscle Tissue - Movement

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Nervous Tissue - Control

Te be continued…

• Muscle and nervous tissue will be extensively covered in their respective systems • Take Away… – 3 types of muscle tissue: skeletal, cardiac and smoothe • Highly cellular, well vascularized – Nervous Tissue: the cell is the neuron and the system is comprised of the brain, spinal cord and nerves • Regulates and controls bodily functions

Next the Systems

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First up, The Skeletal System…