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Chapter 1 The Study of Body Function Remon Wahba, MD Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 1 Outline Introduction to Physiology Scientific Method Homeostasis Tissues: Muscle Tissue Nervous Tissue Epithelial Tissue Connective Tissue Organs & Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Human Physiology Physiology: Study of the function of the body How the body works to Maintain Life Cell & Tissue Organs Systems Pathophysiology: How physiological processes are altered in disease or injury 1-3 Scientific Method 1-4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Scientific Method Four Steps: Observation Hypothesis Experiment Conclusion Theory General statement explaining natural phenomena that is based on proven hypotheses (Experiments) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Testing of Hypotheses Involves: Experimental Quantitative Analysis & control groups measurements performed blindly of data 1-6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Using Scientific Method to Develop New Drugs When a new drug is suggested by experiments: First step Test Its effectiveness & toxicity in: Tissue culture Experimental animals Rats Mice 1-7 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Using Scientific Method to Develop New Drugs Clinical Trials performed Phase I Trials: Toxicity & metabolism tested in healthy human volunteers Phase II Trials: Effectiveness & toxicity tested in target population Phase III Trials: Widespread test of drug in diverse population Phase IV Trials: Drug is tested for other uses 1-8 Homeostasis 1-9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Homeostasis Maintenance of the internal environment Constant Dynamic Constancy Around physiological set points Failure of Homeostasis leads to illness or death Maintained mainly by Negative Feedback Loops 1-10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Homeostasis Two Regulatory Mechanisms: Intrinsic Control is built-in the organ being regulated Extrinsic Control comes from outside of organ by Nervous System Nervous control of Body Temperature Endocrine system Hormonal control of Blood Glucose level 1-12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Homeostasis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Homeostasis Negative The Feed Back response opposes the stimulus To counteract further changes and bring Homeostasis Positive The To Feed Back response enhances the original stimulus speed up the change Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Negative Feedback Loops Sensor: Detects deviation from set point Integrating center: Determines response Effector: Produces response Fig 1.1 1-11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Negative Feedback: The Control of Body Temperature Figure 1.5 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Negative Feedback: The Control of Blood Pressure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Negative Feedback Hormonal Control of Blood Glucose Fig 1.6 1-13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Positive Feedback Loops Self-Amplifying change The response enhances the original stimulus Normal way of producing rapid changes Occurs with childbirth, blood clotting, protein digestion, and generation of nerve signals Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Positive Feedback Loops “Childbirth” Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Positive Feedback Loops “Blood Clotting” Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tissues Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tissues Tissues: Groups of specialized cells organized to perform a limited number of functions Histology = study of tissues Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tissues The Four primary types of tissue are: Epithelial Connective Muscular Nervous Epithelial Tissue 1-14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Epithelial Tissue Covers body surfaces & Lines body cavities Separated from underlying tissue by Basement Membrane Consists of cells that form: Membranes Glands Does not contain Blood Vessels (Avascular) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Epithelial Tissue (cont) Cells Cells are Regularly Replaced are Tightly Joined together with small amount of matrix (intercellular substances) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Epithelial Tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Classification of Epithelial tissue According to: Number of Layers of Cells Simple (one layer) Stratified (more than one layer) Shape of Apical Cells Squamous epithelial cells are flattened Cuboidal epithelial cells are cube-shaped Columnar epithelial cells are taller than wide Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stratified Squamous Epithelial Tissue Non-keratinized Stratified Squamous consists of living cells Mouth Cavity, Vagina… Keratinized Stratified Squamous has outer layer of dead cells contain water-resistant keratin Skin. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stratified Squamous Epithelial Tissue Non-keratinized Stratified Squamous consists of living cells Mouth Cavity, Vagina… Keratinized Stratified Squamous has outer layer of dead cells contain water-resistant keratin Skin. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Keratinized Stratified Squamous Epithelial Tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Simple Cuboidal Epithelium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Simple Columnar Epithelium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pseudo-Stratified Columnar Epithelium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stratified Columnar Epithelium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Transitional Epithelium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Exocrine Glands Derived from epithelial cells Secrete via ducts Can be simple tubes or clusters called acini Connective Tissue 1-30 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Connective Tissue Has lots of Extra cellular Material deposited in spaces between its cells Includes Connective Tissue Proper Loose & Dense Fluid Connective Tissue Blood & Lymph Supportive Connective Tissue Cartilage & Bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Areolar Connective Tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Adipose Connective Tissue Specialized for fat synthesis, breakdown & storage Fig 1.18 1-33 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Adipose and Reticular Tissues Figure 4.11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dense Connective Tissue Dense Fibrous Connective Tissue packed with fibers of collagen Two Types: Dense Regular As in Tendons Dense Irregular Capsules, Dermis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dense Regular Connective Tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dense Irregular Connective Tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fluid Connective Tissue, Blood Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fluid Connective Tissue, Blood Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supporting Connective Tissue (Cartilage) Specialized Made for Support, Protection of Chondrocytes & Elastic extracellular material Serves Forms as precursor for bone Articular Surfaces for Joints 1-34 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cartilage Three Types: Hyaline Elastic Fibro Cartilage Cartilage Cartilage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hyaline Cartilage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Elastic Cartilage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fibrocartilage Figure 4.15d Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supporting Connective Tissue (Bone) Formed as concentric layers of calcified material Contains 3 cell types: Osteoblasts: bone-forming cells Osteocytes: trapped, inactive osteoblasts Osteoclasts: bone resorbing cells Fig 1.19 1-35 Muscle Tissue 1-23 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Muscle Tissue Specialized 3 Types: Skeletal Cardiac Smooth for contraction Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skeletal Muscles Striated Voluntary Attached to the skeleton Muscle fibers: Formed by fusion of Embryonic Myoblasts Large & Multinucleated Individually controlled Lined-up in parallel to form bundles Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skeletal Muscles Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cardiac Muscle Striated; Involuntary; in the Heart only Branched to form continuous fabric Intercalated discs between cells provide mechanical & electrical interconnections Fibers not individually controlled Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cardiac Muscle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Smooth Muscle Unstriated Involuntary Found in the walls of all Hollow Organs Intestine, Blood Vessels..etc) Controlled by ANS Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Smooth Muscle Nervous Tissue 1-20 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nervous Tissue Consists of: Neurons Supporting or glial cells (Neuroglia) Neurons are specialized for conducting electrical signals Have 3 basic components: Cell body Dendrites Axon 1-21 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Neurons Cell body Contains nucleus; is metabolic center Dendrites: Highly branched extensions off cell body Receive inputs from other neurons Conduct impulses to cell body Axon: Single, long extension off cell body Conducts nerve impulses to other cells 1-22 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Neurons Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supporting Cells Supporting/Glial cells Provide physical & functional support for neurons Perform Phagocytosis 5X more abundant than neurons Organs & Systems 1-36 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Organs & Systems Organs: Are anatomical & functional units made up of 2 or more primary tissues grouped together to perform a specific function Systems: Are groups of organs working together to perform certain function / functions to maintain Homeostasis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stem Cells Most cells in organs are highly specialized or differentiated Many organs retain small populations of adult stem cells (Undifferentiated Cells) Can become many cell types E.g. bone marrow stem cells can give rise to all of the different blood cell types Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skin The Largest Organ Has Three layers Epidermis for protection Dermis Contains connective tissue, glands, blood vessels, nerve receptors Hypodermis Contains fatty (Adipose) tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skin Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skin Other structures: Hair Follicles Sweat Glands Sebaceous Glands Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Body-Fluid Compartments The Body has 2 Fluid Compartments: Intracellular; inside the cells Extracellular; outside the cells Separated by cell’s outer membrane Extracellular is composed of Blood Plasma The fluid component of blood Interstitial fluid Fluid in between body cells 1-39