1. An Introduction to Animal Structure and Function

2. Animal Needs All animals have a few tenants in common: –They must obtain oxygen from the environment –They must acquire nourishment; and –They must excrete waste To study these tenants we look at an animals: –Anatomy: the structure of an organism; and –Physiology: the functions an organism performs

3. Tissue Types Basis of anatomy are tissues: –Epithelial (barrier against mechanical injury, microbes, and fluid loss) –Connective (binds and supports other tissues) –Muscle (movement) –Nervous (senses stimuli and transmits signals)

4. Tissues: Epithelial Epithelial: outside of body and lines organs and cavities; held together by tight junctions (specific proteins that form a “seal” around the cells) Types of epithelial tissues –Simple: single layer of cells –Stratified: multiple tiers of cells Pseudostratified: single layer of cells, but appears stratified because the varying cell lengths Basement membrane: dense mat of extracellular matrix that form the base of the epithelial layer

5. Tissues: Epithelial Cell shapes –Cuboidal (like dice) –Columnar (like bricks on end) –Squamous (like floor tiles) Glandular epithelia (absorb or secrete chemical solutions, example: mucous membranes)

6. Tissues: Epithelial

7. Tissues: Connective Connective: bind and support other tissues; scattered cells through the extracellular matrix; –Collagenous fibers (collagen protein): nonelastic and do not tear easily (keeps flesh from tearing away from bone) –Elastic fibers (elastin protein): has a rubbery quality that allows the protein to be stretched and then pulled back to original shape –Reticular fibers (thin branched collagen fibers): form a tightly woven “fabric” that joins connective tissue to adjacent tissues

8. Tissues: Connective Loose connective tissue: binds epithelia to underlying tissue; holds organs Found in loose connective tissue –Fibroblasts- cells that secrete extracellular proteins –Macrophages- amoeboid WBC’s; phagocytosis –Adipose tissue: stores fat in adipose cells (pads and insulates body and stores fuel) Fibrous connective tissue: parallel bundles of cells (maximizes nonelastic strength) –Tendons: connects muscle to bone –Ligaments: connects bone to bone (joints)

9. Tissues: Connective Cartilage: collagen in a rubbery matrix (chondroitin); flexible support (acts as cushion between vertebrae or joints) Bone: mineralized tissue by osteoblasts (provides strength and support for body) Blood: liquid plasma matrix; erythrocytes (RBC’s) carry O 2 ; leukocytes (WBC’s) immunity; platelets for clotting

10. Tissues: Connective

11. Tissues: Nervous Nervous: senses stimuli and transmits signals from 1 part of the animal to another –Neuron: functional unit that transmits impulses –Dendrites: receives signals from other neurons –Axons: transmits impulses toward another neuron or effector

12. Tissues: Nervous

13. Tissues: Muscle Muscle: composed of muscle fibers that are capable of contracting when stimulated by nerve impulses; myofibrils (contraction unit) are composed of the proteins actin and myosin –Skeletal: voluntary movement (striated); attached to bones by tendons, can only contract –Cardiac: contractile wall of heart (branched striated); although striated, it is still involuntary –Smooth: involuntary activities (no striations); examples: digestion, movement of arteries

14. Tissues: Muscle

15. Organ systems Organ: organization of tissues Mesentaries: suspension of organs (connective tissue) Thoracic cavity (lungs and heart) Abdominal cavity (intestines) Diaphragm (respiration); separates the thoracic and abdominal cavities Digestive-food processing Circulatory-internal distribution Respiratory-gas exchange Immune/Lymphatic-defense Excretory-waste disposal; osmoregulation Endocrine-coordination of body activities (hormones) Reproductive-reproduction Nervous-detection of stimuli Integumentary-protection Skeletal-support; protection Muscular-movement; locomotion

16. Microscope Activity You will be examining various slides of animal tissues In your lab notebooks, I want you to draw what you see at the 100X and 400X powers and label as many parts as you can –You may use your textbooks for aid (look at the diagrams on pp.824-826)

17. Metabolism Bioenergetics and Thermoregulation

18. Bioenergetics All organisms require chemical energy for normal physiological processes The flow of energy through an animal is called bioenergetics –Food is the source of the chemical energy needed to survive (remember cellular respiration) –Creation of ATP

19. Metabolic Rate To gain a further understanding of energy usage, scientists measure energy uses for life processes to come up with a metabolic rate (the sum of all the energy-requiring biochemical reactions occurring over some time interval) –Energy is measured in calories (cal) or kilocalories (kcal)

20. Determining Metabolic Rate Since nearly all energy that is used in cellular respiration eventually appears as heat, we can measure rate of heat loss –Use a calorimeter Can also measure the amount of O 2 used or CO 2 produced through oxidative phosphorylation (remember Kreb’s cycle and electron transport chain) Rate of food consumption over long period of time –Not very accurate because a lot of food can be stored as fat

21. Bioenergetic Strategy Many organisms have different “life” strategies that utilize energy differently –Endothermic: warm-blooded; their bodies are warmed by metabolism and temperature is maintained in a narrow range (98.6 ̊F in humans) Mostly in birds and mammals –Ectothermic: cold-blooded; their bodies are warmed by external sources Lower energy cost for animal Mostly in fish, amphibians, reptiles and invertebrates

22. Influence on Metabolic Rate Many factors also contribute to the metabolic rate of animals –Size: in general, the smaller the animal, the higher the metabolic rate (mice and other rodents use about 20 times more energy/gram than an elephant) –Activity: basal metabolic rate (BMR); the basic amount of energy needed to sustain basic life functions Average human male: 1600-1800 kcal Average human female: 1300-1500 kcal In general, the more “fit” an individual, the higher the BMR (swimmers, runners, etc)

23. Metabolic Activity in Ectotherms In ectotherms, the amount of energy needed to sustain life functions is determined by the environment (this is where they get their energy to regulate their temperature) In ectotherms, we use a standard metabolic rate (SMR) which is based on a specific temperature range

24. Internal Environments How organisms regulate their internal anatomy

25. Homeostasis Organisms have many strategies to maintain their internal environment –interstitial fluids (fills the spaces between cells) are responsible for exchanging waste and nutrients –The goal of metabolism is to maintain a balanced “steady-state” condition where all materials and temperatures within the body are in homeostasis a narrow range of optimal conditions that allow an organism to resist change

26. Homeostatis Strategies Regulator: uses internal mechanisms to moderate fluctuations in the environment –Example: Shivering is your bodies response to cold (kinetic energy produces heat to warm you up) Conformer: organism is able to alter their physiological state to suit their environment –Example: Ectotherms alter their body temperature and metabolism based on temperture Most organisms are not JUST regulators or conformers, but have a wide variety of strategies to deal with their environment

27. Mechanism of homeostasis To enact regulation, any control system has 3 parts: 1) receptor (to sense the changing condition); 2) control center (to process the condition); and 3) effector (the appropriate response) There are two ways in which to enact this regulation Negative feedback: change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation; i.e., body temperature Positive feedback: physiological control mechanism in which a change in some variable triggers mechanisms that amplify the change; i.e., uterine contractions at childbirth

28. Thermoregulation – negative feedback Example: Thermoregulation (maintaining a specific range of temperature) –Body senses temperature change (nerves in skin) –The impulses are sent to the brain to process –Appropriate response

29. Other Strategies of Thermoregulation There are 4 basic strategies of heat transfer: –Conduction: direct transfer of heat from objects touching (lizard on a warm rock) –Convection: transfer of heat by the movement of air or liquid (a breeze cooling you down) –Radiation: transfer of heat through space by some form of electromagnetic waves (warming up in the sunlight) –Evaporation: removal of heat from a surface by converting a liquid to a gas (sweating)

30. Heat Loss vs. Heat Gain Organisms need to use different heat transfer strategies to balance heat loss with heat gain (maintain temperature homeostasis) –Insulation: many organisms have different strategies to limit heat loss or gain through insulation (skin, hair, feathers, fat) Most of the insulation is provided by the air trapped by the hair or fur, or The layers of fat in the adipose tissue in the hypodermis (lowest layer of skin)

31. Heat Loss vs. Heat Gain Control of blood flow –In endotherms, vasodilation (blood vessels expand) increases blood flow to the skin and warms the skin (blood is from your core) –To cool the skin, vasoconstriction (blood vessels contract) reduce blood flow to skin

32. Marine Animals An important strategy for many marine mammals and birds is countercurrent heat exchange –Blood vessels are arranged so that warmer, internal blood vessels, are near blood vessels that are sending blood to extremities –The warmer blood increases the temperature of the cooler blood

33. Heat Loss vs. Heat Gain Cooling with evaporation –Can lose heat by evaporation through the skin (sweat) or when they breathe (water vapor) Dogs panting Birds have a pouch of blood vessels in the floor of their mouth (panting releases the heat from the blood) Sweat glands in skin Spreading saliva on body

34. Energy and Temperature Regulation Behavioral responses can help with thermoregulation and energy “savings” during stressful environmental conditions –Reptiles and amphibians “basking” in the sun; or finding shade when hot out –Migration during winter –Organisms huddle together when cold –Some organisms are only active when it is warm enough

35. Energy and Temperature Regulation –Temperature can induce the body to make brown fat, causes the cells to produce heat instead of ATP –Hibernation during the cold (torpor, reduced physiological state to save energy; lowered body temperature and lowered pulse) –Estivation during hot periods (a state of torpor during extreme heat) –Daily torpor (reduced metabolic activity during certain times of the day)

36. Adjusting to Temperature Animals can also acclimatize to different environment temperature –Mammals and birds adjust the amount of insulation (thicker coat of fur or blubber; or shedding fur) –In ectotherms, changes are often made at the cellular level Produce different enzymes that work at different temperatures, produce biological “antifreeze”