chapter 1 the study of body function remon wahba, md
TRANSCRIPT
Chapter 1The Study of Body
Function
Remon Wahba, MD
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 1 OutlineIntroduction to PhysiologyScientific MethodHomeostasisTissues:
Muscle TissueNervous TissueEpithelial TissueConnective Tissue
Organs & Systems
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Human PhysiologyPhysiology:
Study of the function of the bodyHow the body works to Maintain Life
Cell & TissueOrgansSystems
Pathophysiology: How physiological processes are altered
in disease or injury1-3
Scientific Method
1-4
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Scientific MethodFour Steps:
ObservationHypothesisExperimentConclusion
TheoryGeneral 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 & control groups
Quantitative measurements performed blindly
Analysis 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
ConstantDynamic 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 systemHormonal control of Blood Glucose
level1-12
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 Feed Back The response opposes the stimulus To counteract further changes and bring
Homeostasis
Positive Feed Back The response enhances the original
stimulus To 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 1.11-11
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 1.61-13
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Positive Feedback Loops
Self-Amplifying changeThe 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.
TissuesTissues:
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 are Regularly Replaced
Cells 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 CellsSquamous epithelial cells are flattenedCuboidal epithelial cells are cube-
shapedColumnar 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 cellsMouth Cavity, Vagina…
Keratinized Stratified Squamous has outer layer of
dead cells contain water-resistant keratinSkin.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Stratified Squamous Epithelial Tissue
Non-keratinized Stratified Squamous consists of living cellsMouth Cavity, Vagina…
Keratinized Stratified Squamous has outer layer of
dead cells contain water-resistant keratinSkin.
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 ductsCan 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 IrregularCapsules, 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 for Support, Protection
Made of Chondrocytes & Elastic extracellular material
Serves as precursor for bone
Forms Articular Surfaces for Joints
1-34
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Cartilage
Three Types:
Hyaline Cartilage
Elastic Cartilage
Fibro 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 for contraction
3 Types: Skeletal Cardiac Smooth
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 MuscleUnstriated
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 neuronsPerform Phagocytosis
5X more abundant than neurons
Organs & Systems
1-36
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Organs & SystemsOrgans:
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.
SkinThe Largest OrganHas Three layers
Epidermis for protectionDermis
Contains connective tissue, glands, blood vessels, nerve receptors
HypodermisContains 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.
SkinOther 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 cellsExtracellular; 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