ANIMAL FORM & FUNCTION

1. This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentation • In Slide Show, click on the right mouse button • Select “Meeting Minder” • Select the “Action Items” tab • Type in action items as they come up • Click OK to dismiss this box • This will automatically create an Action Item slide at the end of your presentation with your points entered. ANIMAL FORM & FUNCTION Campbell, 6th ed., Chapter 40 Nancy G. Morris Volunteer State Community College

2. Unifying themes from A & 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

3. Levels of Structural Organization • There is a structure hierarchy of life: atoms -> molecules -> supramolecules -> cell • The cell is the smallest unit of life. • The hierarchy of multicellular organisms is: cells -> tissues -> organs -> organ systems

4. Function Correlates with Structure in the Tissues of Animals • Tissues 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: • Epithelial • Connective • Nervous • Muscle • Blood

5. Epithelial Tissues • Simple – one layer of cells • Stratified or striated – multiple tiers of cells • Pseudostratified – one layer of cells that appears to be multiple because cells vary in length. • Cell shapes are cubodial (like dice), columnar (bricks on end), squamous (like flat floor tiles). • Some are specialized for absorption or secretion. • Some are ciliated. • 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.

6. Connective 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

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

8. Muscle Tissue • Muscle is the most abundant of vertebrate tissues. • Consists of long, excitable cells capable of contraction.

9. Organ systems are 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.

10. Organ systems are interdependent. • Several organs with separate functions that act in a coordinated way make up an organ system. • Systems are interdependent: an organism is a living whole greater than the sum of its parts.

11. Bioenergetics • 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)

12. Energy input(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

13. Metabolic rate provides clues • 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.

14. Metabolic 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

15. Metabolic Rate • Every animal has a range of metabolic rates: • Minimal rates support basic life functions, such as breathing, • Maximal rates occurs during peak activities, such as all-out running.

16. Endo or Ecto? • Endotherms – animals which generate their own body heat metabolically • birds & mammals • Ectotherms – animals that acquire most of their body heat form the environment • fish, amphibians, reptiles, & invertebrates

17. Metabolic 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.

18. Body Plans & External Environment • Physical 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-bearing, since crouched posture is partly a function of muscle contraction, powered by chemical energy.

19. Body size and shape affect 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…..

20. Body size and shape affect interactions 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)

21. Body size and shape affect interactions 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

22. Mechanisms 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

23. Mechanisms 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)