Basic Principles of animal form & function

1. Campbell & Reece Chapter 40 Basic Principles of animal form & function

2. Definitions • Anatomy: structure of an organism • Physiology: processes & functions of an organism

3. Evolution of Animal Size & Shape • Physical laws influence animal body plans with regard to maximum size. • As body sizes increase: thicker skeletons required to maintain adequate support • affects animals with exoskeletons as well as endoskeletons • also affects amt body mass that must be allocated to muscle   @ some pt. locomotion becomes impossible

4. Body Plans • Physical requirements constrain what natural selection can “invent” • the mythical winged dragon could not possibly exist (anything that large could not generate enough lift to take off & fly)

5. Body Plans: Aquatic Animals • Laws of hydrodynamics constrain the shapes possible for aquatic organisms that swim very fast • All animals that swim fast have same fusiform shape • minimizes drag • convergent evolution occurs because natural selection shapes similar adaptations when diverse organisms face the same environmental challenges (resistance of water to fast travel)

6. Convergent Evolution

7. Exchange with the Environment • Animals must exchange materials with their environments which also imposes limitations on their body plans • rates of exchange for nutrients, wastes, & gases is proportional to membrane surface area • amt material necessary to sustain life is proportional to cell vol.

8. Exchange in Multicellular Animals • works only if every cell has access to a suitable aqueous environment (either in or out of animal’s body)

9. Aqueous Environment Required • exchange with environment occurs as dissolved substances diffuse or are transported across plasma membranes • ex: unicellular protists living in water has sufficient surface area to serve its entire volume: surface area/vol ratio important physical constraint on size of unicellular organisms

11. Exchange with the Environment • Interstitial Fluid: fluid that fills space between cells in multicellular organisms; allows all cells to have contact with aqueous environment • complex body systems can filter & adjust composition of interstitial fluid

12. Interstitial Fluid

13. Exchange with the Environment • Animals of diverse evolutionary histories & varying complexity must solve how to obtain energy, oxygen, how to get rid of wastes & manage movement • All animals must obtain food for nrg, generate body heat, & regulate internal temperature, sense & respond to external stimuli

14. Hawk Moth • Its probiscus extends as a straw thru which moth sucks nectar from deep w/in tube-shaped flowers

15. Bioenergetics • how organisms obtain, process, & use nrg resources: a connecting theme in the comparative study of animals

16. Organization of Body Plans

17. Definitions • Cells: basic unit of structure & function in living things; cells form a functional animal body thru their emergent properties • Tissues: groups of cells with similar appearance & a common function • Organs: different types of tissues grouped together into functional units • Organ Systems: groups of organs that work together with a common function

18. Organization of Body Plans • simplest animals lack true tissues & organs

19. Organ Systems in Mammals

20. Organ Systems in Mammals

21. Organ Systems in Mammals

22. Organ Systems in Mammals

23. Organ Systems in Animals • built from a limited set of cell & tissue types • 4 tissue types: • Epithelial • Connective • Muscle • Nerve

24. Epithelial Tissue • Epithelium (singular); Epithelia (plural) • sheets of cells • cover outside of body or line organs & cavities w/in body • closely packed cells often w/ tight jcts: so can function as protection vs.. mechanical injury, infection, fluid loss • 5 cell types

25. 1. Cuboidal Epithelial Cells • cubes, dice • specialized for secretion • found: • renal tubules • glands

26. 2. Simple Columnar Epithelium • large brick-shaped • functions: secretion, absorption • found: lines intestines

27. 3. Simple Squamous Epithelium • plate-like cells • functions: diffusion • found: lining blood vessels, air sacs in lungs (alveoli)

28. 4. Pseudostratified Columnar Epithelium • single layer that appears to be >1 layer • cells are of different hts • +/- ciliated • form mucous membranes (lines cavities that open to exterior of body) • found: lining respiratory tract where beating cilia move film of mucus with any trapped material away from lungs

29. Pseudostratified Columnar Epithelium

30. 5. Stratified Squamous Epithelium • multiple layers of cells; top layer squamous • regenerates rapidly/ new cells formed on basement membrane…upper cells sloughed off • function: protection • found: on surfaces subject to abrasion

31. Stratified Squamous Epithelium Keratinized Nonkeratinized

32. Connective Tissues • tissue type with sparsest density of cells • main cell: fibroblast: secrete fiber proteins like collagen • also macrophages (phagocytes) • cells in extracellular matrix • made up of web of fibers embedded in liquid, jelly-like, or solid foundation • functions: • holds tissues together & in place

33. 3 Connective Tissue Fibers • Collagenous • provide strength & flexibility • Reticular • join CT to adjacent tissues • Elastic • make tissues elastic

34. Loose CT • vertebrates:mostwidespread of 3 types • binds epithelia to underlying tissues • holds organs in place • has all 3 fiber types • higher % matrix than others

35. Fibrous CT • dense w/collagen fibers • found in tendons (attach muscle to bone) & ligaments (attach bone to bone)

36. Bone • mineralized CT • Osteoblasts: bone-forming cells lay down matrix of collagen then Ca++, Mg++, & PO4-- combine into hard mineral • Osteons: repeating microscopic units that make up bone

37. Blood • CT with liquid matrix called plasma • water , salts, dissolved proteins • cells suspended in plasma • RBCs: O2 • WBCs: fight infection • Platelets: cell fragments used for clotting

38. Adipose Tissue • specialized loose CT that stores fat in adipose cells • Function: • pads & insulates • stores fuel

39. Cartilage • collagen in rubbery protein-carbohydrate complex called chondroitin sulfate secreted by cells called chondrocytes • makes cartilage strong but flexible • many vertebrate skeletons start as cartilage  replaced by bone

40. Muscle Tissue • responsible for nearly all types of body movement • made of filaments with actin & myosin (contractile proteins) • cells called muscle fibers • 3 types: • Skeletal • Smooth • cardiac

41. Skeletal Muscle • attached to bones by tendons • striated • voluntary • muscle fibers form by fusion of several cells so appear multinucleated • sarcomere: contractile units (actin/myosin)

42. Smooth Muscle • nonstriated • involuntary • spindle-shaped cells • in walls of organs • Esophagus/Stomach • Intestines • Bladder • Arteries & Veins

43. Cardiac Muscle • striated • involuntary • found only in heart • intercalated disc: connections between cardiac fibers which relay signals from cell to cell  synchronizes heart contractions

44. Nervous Tissue • receives , processes, & transmits information • cells: neurons: transmit action potentials • supportive cells: glial cells • many animals have a concentration of nervous tissue = a brain (information processing center)

45. Neurons • basic unit of nervous system • receive nerve impulses (action potentials) from other neurons or sensory organs via dendrites or cell body  impulse to next neuron (muscle fiber, gland) via axon • nerve: bundle of axons

47. Glia • various types: all help nourish, insulate, & replenish neurons • some modulate neuron function

48. Coordination & Control • The endocrine & nervous systems are the 2 means of communication between different locations in body. • Endocrine system releases signaling molecules called hormones via blood  target cells (have the correct receptors) • Nervous system uses cellular circuits involving electrical & chemical signals to send information to specific locations

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