Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.1 CHAPTER 40 INTRODUCTION TO ANIMAL FORM AND FUNCTION Prepared by Brenda Leady, University of Toledo

2 All animal cells share similarities in the ways in which they  Exchange materials with their surroundings   Synthesize complex molecules  Duplicate themselves 

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4 Tissues Specialized cells of a given types cluster together 4 categories 

5 Muscle tissue Cells specialized to … 3 types  _____________ – attached to bone or exoskeleton for locomotion, voluntary control  _____________ – surrounds hollow tubes and cavities for propulsion of contents, involuntary control  _____________ – only in the heart, involuntary control

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7 Nervous tissue Initiate and conduct electrical signals from one part of the animal’s body to another Electrical signals produced in one nerve cell may stimulate or inhibit other nerve cells to 

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9 Epithelial tissues Sheets of _________________cells that  Specialized to ___________ and _________ or ____________ Rest on basal lamina or basement membrane Can function as selective barriers

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11 Connective tissues Includes … Form an extracellular matrix around cells  Provides … 

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13 Organs Organ system – different organs work together to perform an overall function Organ systems frequently work together – nervous and endocrine system Spatial arrangement of organs into organ systems part of overall body plan Body plan controlled by highly conserved family of genes with homologs in all animals

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Organ Development and Function Are Controlled by Homeotic Genes Homeotic genes – family of ancient highly conserved genes found in all animals Determine timing and spatial patterning of the anteroposterior body axis during development In vertebrates known as Hox genes Important role in determining where organs form Hox genes also important for growth, development and function of organs in adults

16 Body fluids 2 main compartments  _________________– inside cells  _________________– outside cells ______________ – fluid portion of blood ______________– fluid between cells Separate in closed systems Hemolymph intermingles to fluids in many inverts Intracellular and extracellular fluid can be very different in solute composition

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18 Movement of water Plasma membranes tend to … Fluid moves readily between compartments  Swollen or shrunken cells do not operate well Can happen when cells exposed to more dilute (hypoosmotic) or more concentrated (hyperosmotic) extracellular fluids

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20 Movement of solutes  Movement of a solute down its concentration gradient  No carrier or ATP required  Only lipid soluble molecules  Facilitated diffusion – passive  Active transport

21 Structure and function Key theme is structure determines function Compare respiratory systems of insect and mammal  Structural similarities suggest similar function 

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23 All organs that mediate diffusion or absorption have an … Increased space requirements avoided by shape changes  SA/V – surface area to volume ratio

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25 Homeostasis _____________ – maintain same fluid composition as environment – cheaper _____________ – internal composition of fluids different from environment – more expensive Animal can be both with respect to different variables

26 No physiological function is constant for very long, which is why we call them “variables” Normally, blood sugar (glucose) remains at fairly steady and predictable levels in any healthy individual After a meal the level of glucose in your blood can increase quickly If you skip a meal, your blood sugar level may drop slightly Homeostatic mechanisms restore blood glucose to normal levels in the blood

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28 Homeostatic control systems ______________ – monitors particular variable ______________ – compares signals from the sensor to a baseline set point ______________ – compensates for deviations between actual value and set point Example – body temperature in mammals

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30 Feedback Fundamental feature of homeostasis Major way disturbances are minimized

31 Variable being regulated brings about responses that move the variable in the _______________ direction Decrease in body temperature leads to… May occur at organ, cellular or molecular level

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33 Far less common _______________ the direction of the change Birth in mammals

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35 Feedforward regulation Animal’s body begins preparing for a change in some variable before it occurs Speeds up homeostatic responses and minimizes deviations from the set point Many result from or are modified by learning

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Pavlov Demonstrated the Relationship Between Learning and Feedforward Processes Demonstrated that feedforward processes associated with digestion could be conditioned to an irrelevant stimulus Used ticking metronome (not ringing bell) Conditioned stimulus by itself can elicit increased salivation Other sounds and stimuli also worked Conditioned response not permanent

39 Local homeostatic responses Some homeostatic responses may be highly localized _______________________– molecules released into interstitial fluid to act on nearby cells _______________________ released from one nerve cell travel to an adjacent nerve cell In contrast, hormones are chemical messengers produced in a gland, secreted into the blood, and act on distant cells