Homeostasis and the Homeostasis and the Organization of the BodyOrganization of the Body

Chapter 32

HomeostasisHomeostasis

State of balance within the bodyMaintaining body conditions within set

limits

Regulating body temperatureRegulating body temperature

Endotherms (“inside heat”)– Produce heat by metabolic reactions– Ex. Birds and mammals

Ectotherms (“outside heat”)– Obtain heat from environment (i.e. basking in

the sun)– Ex. Reptiles, amphibians, most fish,

invertebrates

Warmer temperatures = Warmer temperatures = higher metabolic ratehigher metabolic rate

Cold lizardsHummingbirdsHeat stroke and frostbite in endotherms

Feedback SystemsFeedback Systems

Method of maintaining internal environment

Negative feedback – method for keeping body conditions within a normal range and maintaining homeostasis

Positive feedback – substance or condition that acts within a system to produce more of the same activity

Negative FeedbackNegative Feedback

Negative FeedbackNegative Feedback

Negative FeedbackNegative Feedback

Positive FeedbackPositive Feedback

Comparing the Two Types Comparing the Two Types of Feedback Mechanisms of Feedback Mechanisms

How is the animal body organized?How is the animal body organized?

Tissues are composed of Tissues are composed of similar cellssimilar cells

4 Major Categories– 1. Epithelial tissue– 2. Connective tissue– 3. Muscle tissue– 4. Nervous tissue

Tissue Type 1Tissue Type 1: : Epithelial tissueEpithelial tissue

Forms protective covering for the bodyCovers the outside of the body (skin)Lines the body cavities, hollow organs (i.e.

digestive, respiratory, urinary, reproductive), and ducts (i.e. blood vessels)

Classification of Epithelial TissueClassification of Epithelial Tissue Based on shape and layers Simple epithelium

– One layer– Ex. Found in digestive, respiratory, and circulatory

system

Stratified epithelium– Multiple layers– Ex. Found in mouth and skin– Covered with many layers of dead cells– These cells and others below contain keratin

Makes skin water-resistant, flexible, and tough

Classification of Classification of Epithelial TissueEpithelial Tissue

Simple Squamous EpitheliumSimple Squamous Epithelium

OU. 2011. http://www.biosci.ohiou.edu/introbioslab/Bios171/images/lab1/simple_squamous.jpg

APSU. 2010. http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam%

Simple Columnar EpitheliumSimple Columnar Epithelium

King, David. 2001. SIUC. http://www.siumed.edu/~dking2/erg/images/GI125b.jpg

Goblet cell - mucus-secreting gland cell

Simple Cuboidal EpitheliumSimple Cuboidal Epithelium

Stratified Squamous EpitheliumStratified Squamous Epithelium

NKU. 2011. http://www.nku.edu/~dempseyd/stratified%20squamous%20epithelium.gif

Pseudostratified Ciliated Pseudostratified Ciliated Columnar EpitheliumColumnar Epithelium

Palomar. 2011. http://faculty.palomar.edu/ggushansky/histology/images/pseudostratified%20ciliated%20columnar%

GlandsGlands

Single cells (i.e. goblet cells) or groups of cells (i.e. salivary, mammary, sweat) that secrete substances outside the cell

2 types of glands– Exocrine Glands– Endocrine Glands

http://commonsensehealth.com/uploads/endocrineglands.gif

Exocrine GlandsExocrine GlandsSecrete non-hormonal substances into a

body cavity or onto body surface usually through a duct– Sweat glands – Sebaceous glands (oil glands)– Salivary glands– Exocrine glands in stomach and small intestine

http://www.gopetsamerica.com/anatomy/illustrations/pancreas.jpg

http://www.biologycorner.com/anatomy/digestive/salvary-glands.jpg

Endocrine glandsEndocrine glands

Lack ductsSecrete hormones that

diffuse into nearby capillaries

Hormones – chemical produced that are transported by bloodstream to regulate activity of cells

http://nutritiondoctordirect.com/images/endo.gif

Tissue Type 2Tissue Type 2: : Connective TissueConnective Tissue

Main function is to support and bind other tissues Cells are embedded in a matrix of extracellular

substances– Fluid– Flexible proteins

Collagen – the most abundant

4 main types:– Liquid connective tissue– Soft connective tissue– Fibrous connective tissue– Hard connective tissue

Liquid TissueLiquid Tissue Cells are suspended in a fluid matrix Ex. Blood

– Cellular portion Red blood cells White blood cells Platelets (cell fragments)

– Extracellular portion Plasma (fluid)

Soft Connective TissueSoft Connective TissueLoose Connective Tissue

– Cells (fibroblasts) in jellylike matrix– Cells secrete protein fibers and collagen protein– Most common type of tissue in the body– Found in membranes around vessels and

organs, between muscles, and under skin

Adipose (fat) Tissue– Stores fat for energy– Serves as insulation– Serves as protective padding for joints and

organs

Soft Connective TissueSoft Connective Tissue

Loose connective tissue Adipose tissue

Fibrous (Dense) Connective TissueFibrous (Dense) Connective Tissue

Cells = fibroblastsContains collagen fibersOften densely packed in

a parallel arrangement which gives flexibility and strength

Ex. Tendons (connects muscle to bones)

Ex. Ligaments (connects bone to bone)

Hard Connective TissueHard Connective Tissue Cartilage

– Thick, nonliving matrix– Matrix composed of collagen which is

produced by the cartilage cells– Flexible and resilient– Covers ends of long bones, forms

framework for respiratory passages, supports ears and nose, spinal discs

Bone– Matrix hardened by calcium deposits– Forms in concentric circles around a

central canal (contains blood vessels)

Hard Connective TissueHard Connective Tissue

Bone Cartilage

Tissue Type 3Tissue Type 3: : Muscle TissueMuscle Tissue

Produces movement by contraction– Able to shorten and relax

3 types of muscle tissue– Skeletal muscle– Cardiac muscle– Smooth muscle

Skeletal MuscleSkeletal Muscle

Voluntary muscleHeavily striated

– Caused by fibrous proteins in the muscle cells

Produces movement of the skeleton

http://legacy.owensboro.kctcs.edu/gcaplan/anat/study%20guide/Image1006.gif

Cardiac MuscleCardiac MuscleLocated only in the

heartInvoluntary muscleCells connected by gap

junctions through which electrical signals spread through heart

Coordinates cell contraction

Smooth MuscleSmooth MuscleAlso called visceral

muscleInvoluntaryNot striatedProduces slow,

sustained contractions Found in walls of

digestive tract, uterus, bladder, large blood vessels

Tissue Type 4Tissue Type 4: Nervous Tissue: Nervous TissueMakes up brain, spinal cord, nervesBody’s communication system2 types of cells

– Neurons Generate electrical signals Conduct signals to other neurons, muscles, glands

– Neuroglial (“glue”) cells Surround, support, electrically insulate, and protect

neurons Regulate composition of interstitial fluid in nervous

system

Nervous Tissue CellsNervous Tissue Cells

General structure of a neuron1 neuron surrounded by smaller

neuroglial cells

Organs include Organs include 2 or more tissues2 or more tissues

Skin Skin

Protects body against infections and water loss

Helps maintain homeostasisContains outer layer of epithelial tissue

underlain by connective tissue which contains blood vessels, nerves, muscle (sometimes), glands, and adipose

Skin Skin

Jejunum (small intestine) Jejunum (small intestine) Cross-sectionCross-section

http://www.dartmouth.edu/~anatomy/Histo/GI/GI/DMS132/30.gif

Three Embryonic Germ Three Embryonic Germ (Tissue) Layers(Tissue) Layers

http://image.wistatutor.com/content/feed/tvcs/GEREM.JPG

Body CavitiesBody Cavities

Directional TermsDirectional Terms

Directional TermsDirectional Terms

Organ Systems Organ Systems

Consists of 2 or more organs working together to perform common function

11 Organ Systems11 Organ Systems

11 Organ Systems11 Organ Systems

THE ENDTHE END