ANIMAL FORM ANIMAL FORM

& FUNCTION& FUNCTION Campbell, 6th ed., Chapter 40

Nancy G. Morris Volunteer State Community

College

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Unifying themes from A & Unifying themes from A & P:P:

Correlation between form & function

Functions are properties that emerge from the specific shape & order of body parts

Living things have the capacity to respond & adjust to environmental changes

1) over the long term by adaptation & natural selection

2) over the short term by physiological changes

Levels of Structural Levels of Structural OrganizationOrganization

There is a structure hierarchy of life:atoms -> molecules -> supramolecules -> cell

The cellcell is the smallest unit of life.

The hierarchy of multicellular organisms is:

cells -> tissues -> organs -> organ systems

Function Correlates with Structure Function Correlates with Structure in the Tissues of Animalsin the Tissues of Animals

TissuesTissues are groups of cells with a common structure and function.

Cells may be held together by a sticky coating or woven together in a fabric of extracellular fibers.

There are five major groups of tissues:There are five major groups of tissues:– Epithelial Epithelial – ConnectiveConnective– Nervous Nervous – MuscleMuscle– BloodBlood

Epithelial TissuesEpithelial Tissues

SimpleSimple – one layer of cells StratifiedStratified or striated – multiple tiers of cells PseudostratifiedPseudostratified – one layer of cells that

appears to be multiple because cells vary in length.

Cell shapes are cubodialcubodial (like dice), columnarcolumnar (bricks on end), squamoussquamous (like flat floor tiles).

Some are specialized for absorptionabsorption or secretionsecretion.

Some are ciliatedciliated. The structure fits function: simple squamous

epithelium is leaky & is specialized for exchange of materials by diffusion. Found lining the blood vessels and air sacs of the lungs.

Connective TissuesConnective Tissues

Characterized by a sparse cell population scattered through an extensive extracellular matrix.

Functions to bind & support.

Matrix is web of fibers embedded in a homologous substance.

Collagenous fibers – 3 collagen molecules Elastic fibers – long threads of elastin; quick

resilience. Reticular fibers – branched w/ tightly woven Fabric joining connective & adjacent tissues Figure 40.3

Nervous TissuesNervous Tissues

Nervous tissue senses stimuli & transmits signals from one part of the animals to another.

Muscle TissueMuscle Tissue

Muscle is the most abundant of vertebrate tissues.

Consists of long, excitable cells capable of contraction.

Organ systems are Organ systems are interdependent.interdependent.

Tissues are organized into organs in all but the simplest animals.

In some organs, the tissues maybe layered (Figure 40.6).

Organs are suspended by sheets of mesenteries.

Heart & lungs are suspended in the thoracic cavity.

The thoracic cavity is separated from the abdominal cavity by the diaphragm.

Organ systems are Organ systems are interdependent.interdependent.

Several organs with separate functions that act in a coordinated way make up an organ system.

Systems are interdependent: an Systems are interdependent: an organism is a living whole greater organism is a living whole greater than the sum of its parts.than the sum of its parts.

BioenergeticsBioenergetics

Animals are heterotrophs that harvest chemical energy from the food that they eat.

Animals exchange energy with the environment.

As heterotrophs, animals require energy from organic molecules synthesized by other organisms, (Figure 40.7)

Energy inputEnergy input (ingestion of food)(ingestion of food)

Digestion•(emzymatic hydrolysis of food)

Absorption

•(absorption of small energy-containing molecules by body cells)

Catabolism•(cellular respiration & fermentation harvest

chemical energy from food molecules)

Some energy stored Some energy lost as ATP as heat to surroundings

Metabolic rate provides Metabolic rate provides cluesclues

•Bioenergetics:Bioenergetics: the study of the balance between energy intake and energy loss within an organism.

•provides clues as to how an animal adapts to its environment.

Metabolic RateMetabolic Rate

Total amount of energy an animal uses per unit time

Usually measured in calories or kilocalories

Rate based on:– Amount of oxygen used for an

animal’s cellular respiration– Amount of an animal’s heat loss per

unit of time

Metabolic RateMetabolic Rate

Every animal has a range of metabolic Every animal has a range of metabolic rates:rates:– Minimal rates support basic life Minimal rates support basic life

functions, such as breathing,functions, such as breathing,

– Maximal rates occurs during peak Maximal rates occurs during peak activities, such as all-out running.activities, such as all-out running.

Endo or Ecto?Endo or Ecto?

EndothermsEndotherms – animals which generate their own body heat metabolically– birds & mammals

EctothermsEctotherms – animals that acquire most of their body heat form the environment– fish, amphibians, reptiles, &

invertebrates

Metabolic Rate vs. Body SizeMetabolic Rate vs. Body Size

There is an inverse relationship between metabolic rate and size!

Smaller animals consume more calories per gram than larger ones.

Correlated with a higher metabolic rate & need for faster rate of O2 delivery to the tissues.

Smaller animals also have higher breathing rates, blood volumes, heart rates.

Body Plans & External Body Plans & External EnvironmentEnvironmentPhysical support on land depends on

adaptation of body proportions & posture.

– Greater demand for support comes with increased body weight.

– Bioenergetics play a big role in load-Bioenergetics play a big role in load-bearing, since crouched posture is bearing, since crouched posture is partly a function of muscle partly a function of muscle contraction, powered by chemical contraction, powered by chemical energy.energy.

Body size and shape affect Body size and shape affect interactions with the environment…interactions with the environment…

Animal cells must have enough surface area in contact with an aqueous medium to allow adequate environmental exchange of dissolved oxygen, nutrients, & wastes.

Cell size is limited by surface area to volume ratio.

As cell size increases, volume increases proportionately more than surface area. SO…..

Body size and shape affect Body size and shape affect interactions with the environmentinteractions with the environment

Some animals have a body plan that places all cells in direct contact with their aqueous environments;

1) two layered sac – both layers of the body are bathed in water (Hydra).

– 2) Flat-shaped body with maximum surface area exposed to the aqueous environment. (tapeworms)

Body size and shape affect Body size and shape affect interactions with the environmentinteractions with the environment

Complex animals have a smaller surface area to volume ratio & thus lack adequate exchange area on the outer surface.

1) They have highly folded, moist, internal surfaces for exchange (lungs, gills).

2) Circulatory system that shuttles materials between specialized exchange surfaces. Figure 40.10

Mechanisms of HomeostasisMechanisms of Homeostasis

Interstitial fluid– Fills spaces between cells– Exchanges nutrients, wastes,

gases with blood carried in capillaries

Homeostasis depends on feedback– 1) receptor – detects internal change– 2) control center – processes the info

form receptor & informs effector– 3) effector – provides the response

Mechanisms of HomeostasisMechanisms of Homeostasis

As a control system operates: the effector’s response feeds back and influences the magnitude of the stimulus by depressing it = negative feedback (Fig 40.12) OR

the effector’ response feeds back and influences the magnitude of the stimulus by enhancing it = positive feedback.(blood clotting)