Lecture 03 - Form and Function in Animals PDF

Form and Function in Animals BIOL 206 Dr. Jason Lambert Office: BI 365; F 2:00pm – 4:00pm Email: [email protected] Outline Animal Form & Function Recall: Phylogeny & What is an animal Animal Body Symmetry Bo...

Form and Function in Animals BIOL 206 Dr. Jason Lambert Office: BI 365; F 2:00pm – 4:00pm Email: [email protected] Outline Animal Form & Function Recall: Phylogeny & What is an animal Animal Body Symmetry Body cavity structure Structure origins/embryogenesis Segmentation External appendages Body support Animal Anatomy Cells Tissues Organs and organ systems Animal Physiology Surface area:volume relationships Homeostasis Thermoregulation Countercurrent exchange Learning Objectives Identify and describe cellular structures and processes that are unique to animals Identify and describe the major organs and organ systems that make up animal bodies Describe the major tissue types in animals; what cell types comprise them and what are their functions? Describe the origins of these tissue types during embryonic development. Explain why surface area:volume relationships are a challenge for large organisms. Explain what is meant by the terms “phenotypic plasticity” and “homeostasis”. Compare and contrast determinate vs. indeterminate growth.  Figure 30.2 Animal Phylogeny Choanoflagellates ANIMALIA Figure 30.2 Porifera (sponges) What is an animal? Ctenophora (comb jellies) Multicellularity Cnidaria (jellyfish, corals, sea anemones) Defining Features: LOPHOTROCHOZOA Diploblasty Rotifera (rotifers) Loss of Heterotroph coelom Platyhelminthes (flatworms) Internal Digestion Segmentation Annelida (segmented worms) PROTOSTOMES Movement Mollusca BILATERIA Multicellular (snails, clams, squid) ECDYSOZOA Nematoda (roundworms) Bilateral symmetry Arthropoda Triploblasty Segmentation (insects, spiders, Cephalization crustaceans) Coelom? DEUTEROSTOMES DEUTEROSTOMES Radial symmetry Echinodermata (in adults) (sea stars, sand dollars) Chordata Segmentation (vertebrates, tunicates)  Figure 30.2 Animal Phylogeny Choanoflagellates ANIMALIA Figure 30.2 Porifera (sponges) Choanoflagellates Ctenophora (comb jellies) Protist outgroup to animals Multicellularity Cnidaria (jellyfish, corals, sea anemones) LOPHOTROCHOZOA Diploblasty Rotifera (rotifers) Loss of (a) Choanoflagellates are sessile protists; some are colonial. (b) Sponges are multicellular, sessile animals. coelom Platyhelminthes (flatworms) Segmentation Annelida (segmented worms) PROTOSTOMES Multicellular organism Colony Mollusca BILATERIA (cross section) (snails, clams, squid) Choanoflagellate cell Sponge feeding cell (choanocyte) ECDYSOZOA Water Nematoda Food current (roundworms) particles Bilateral symmetry Arthropoda Triploblasty Segmentation (insects, spiders, Cephalization crustaceans) Water current Coelom? DEUTEROSTOMES DEUTEROSTOMES Radial symmetry Echinodermata (in adults) (sea stars, sand dollars) Chordata Segmentation (vertebrates, tunicates) Animal Body Body plan General structure Arrangement of organ systems How functional parts interact Key Features Symmetry Body cavity structure Segmentation External appendages Structural support Animal Body Symmetry Radial symmetry many planes Bilateral symmetry 1 plane of symmetry Animal Body Symmetry – Cephalization Development of an anterior end of the organism clustered with sensory organs Animal Body Acoelomates have no enclosed coelom. No coelom Skin (from ectoderm) Body Cavity Structure Muscles, organs (from mesoderm) Many bilaterian animals have a Gut coelom – a body cavity which (from endoderm) houses the gut and related Pseudocoelomates have an enclosed coelom partially lined with mesodermally derived tissue. internal organs. Pseudocoelom Skin cushions organs (from ectoderm) enables more complex movement Muscles, organs (from mesoderm) Gut (from endoderm) Coelomates have an enclosed coelom completely lined with mesodermally derived tissue. Coelom Skin (from ectoderm) Muscles, organs (from mesoderm) Gut (from endoderm)  The shared anatomical features of animals develop through conserved mecha- Animal Body nisms. After fertilization, the zygote usually divides rapidly, or cleaves, to form many smaller cells; during this cleavage, the embryo, which cannot yet feed, does not grow. This phase of development is initially driven and controlled entirely by Germ Layers theCoelomates completely have in material deposited lined anthe with enclosed coelom egg by the mother. The embryonic genome remains mesodermally derived tissue. inactive until a point is reached when maternal mRNAs and proteins rather Triploblastic animals develop 3 abruptly begin to be degraded. The embryo’s genome is activated, and the cells Coelom cohere to form a blastula—typically a solid or a hollow fluid-filled ball of cells. types of tissue Complex cell rearrangements called gastrulation (from the Skin Greek (from “gaster,” mean- ectoderm) ing “belly”) then transform the blastula into a multilayered structure containing Ectoderm – outermost layer; forms a rudimentary internal gut (Figure 21–3). Some cells of theMuscles, blastula remain organsexter- epidermis and nervous system nal, constituting the ectoderm, which will give rise to the (from epidermis and the ner- mesoderm) vous system; other cells invaginate, forming the endoderm, which will give rise to the gut tube and its appendages, such as lung, pancreas, andGutliver. Another group (from endoderm) Mesoderm – middle layer; forms of cells moves into the space between ectoderm and endoderm and forms the mesoderm, which will give rise to muscles, connective tissues, blood, kidney, and muscles, skeleton, connective various other components. Further cell movements and accompanying cell dif- tissue, and some organs ferentiations create and refine the embryo’s architecture. mesoderm endoderm Endoderm – innermost layer; forms ectoderm gut tube and most other internal organs. CLEAVAGE GASTRULATION fertilized egg blastula gastrula (A) neural tube (ectoderm) somite (mesoderm) Animal Body Germ Layers Potency – the ability of a cell to differentiate Totipotent – can develop into all cell types of the organism Animals: only zygote to 16-cell stage Plants: All cells with a nucleus Pluripotent – can develop into most cell types, but can’t form new embryos Multipotent – partially differentiated, but can become several, related cell types Unipotent – Can self-renew, but can only become one cell type. Animal Body Segmentation Primary functions: The division of the body into a series Sensory of similar structures Feeding Facilitates specialization of body parts Defense Enables complex movement as Walking differentiated parts interact Swimming Segmentation is obvious in annelids and arthropods, but also present in us Animal Body Segmentation The division of the body into a series of similar structures Facilitates specialization of body parts Enables complex movement as differentiated parts interact Segmentation is obvious in annelids and arthropods, but also present in us Animal Body Appendages Movable extensions on a body which are under voluntary control Enable locomotion Arthropods and vertebrates have jointed limbs, specialized for rapid, controlled movements Animal Body Appendages – Example wings Wings have evolved for powered flight independently four times (that we know of) Insects Pterosaurs Birds Bats Animal Body Appendages – Other uses Antennae – sensory organ Mouth parts – capturing prey and chewing food Reproduction Animal Body Body Support 3 types of skeletons: Hydrostatic skeleton – uses fluid pressure in the coelom and muscle contraction to provide locomotion Endoskeleton – organism forms hardened internal structures (bone) which muscles attach to. Exoskeleton – Hardened exterior. Muscles attach to inside. Question from class What skeleton type does an octopus have? An octopus is a mollusk, whose ancestors had a shell (exoskeleton). Most modern cephalopods have no exoskeleton, nor Chambered nautilus: only surviving cephalopod with an external shell endoskeleton, nor a hydrostatic skeleton. Muscles in their appendages push off of each other for support. They have evolved another specialized form of rapid locomotion: jet propulsion! Animal Anatomy Review of animal cells Organelles unique to animal cells: Centrioles Lysosomes Structures unique to animal cells: Tight junctions Desmosomes Gap junctions Animal Anatomy (b) Three-dimensional view of a tight junction Tight junctions Review of animal cells Plasma membranes of adjacent cells Organelles unique to animal cells: Membrane proteins bind to one another to form a tight junction. Centrioles Lysosomes Structures unique to animal cells: Tight junctions Desmosomes Gap junctions Space between cells Animal Anatomy Review of animal cells Organelles unique to animal cells: Centrioles Plasma membranes of adjacent cells Lysosomes Linking proteins Structures unique to animal between cells cells: Anchoring proteins inside cells Tight junctions Intermediate Desmosomes filaments inside cells Gap junctions Desmosome Space between cells Animal Anatomy Review of animal cells Organelles unique to animal cells: Centrioles Lysosomes Structures unique to animal Gap cells: junctions Tight junctions Desmosomes Gap junctions Membrane proteins in adjacent cells line up to form a channel. Space between cells Animal Anatomy Review of animal cells Organelles unique to animal cells: Centrioles Lysosomes Tight junctions seal cells Structures unique to animal together. cells: Tight junctions Desmosomes connect the Desmosomes cytoskeletons of cells. Gap junctions Gap junctions act as channels between cells. Space between cells (a) Gap junctions create gaps that connect animal cells. Membrane exterior Membrane interior Gap junctions Membrane proteins in adjacent cells line up to form a channel. 0.1 µm E face P face (b) Plasmodesmata create gaps that connect plant cells. Cell walls Plasmodesma Smooth with a tubule of endoplasmic endoplasmic reticulum reticulum passing through Cell wall Cell wall of cell 1 of cell 2 0.1 µm Membrane Membrane of cell 1 of cell 2 Animal Anatomy Review of animal cells Organelles unique to animal cells: Centrioles Lysosomes Tight junctions seal cells Structures unique to animal together. cells: Tight junctions Desmosomes connect the Desmosomes cytoskeletons of cells. Gap junctions Gap junctions act as channels between cells. Space between cells Animal Anatomy 4 Tissue Types: Epithelial Connective Nervous Muscle Animal Anatomy Epithelial Tissue Sheets of tightly connected cells Create boundaries between inside and outside the body Form linings of blood vessels and interior of hollow internal organs Control filtration and transport of material into/out of the body Animal Anatomy Epithelial Tissue (a) Simple epithelium consists of a (b) Stratified epithelium consists of Sheets of tightly single layer of cells. multiple layers of cells. connected cells Apical side Create boundaries between inside and Basolateral side outside the body Form linings of blood vessels and interior of hollow internal organs Epithelial cells Epithelial cells Control filtration and transport of material into/out of the body Basal Basal lamina lamina Basolateral side Basolateral 10 μm 20 μm side Animal Anatomy Connective Tissue Disconnected, dispersed cells secrete extracellular matrix for support of other tissues/organs Extracellular matrix (ECM) is composed of protein fibers: Collagen Elastin 2 types of Connective Tissue: Loose – less ECM; soft, fluid-like Dense – more ECM; more rigid, structural support. Animal Anatomy Cartilage from a pig’s ear Connective Tissue Disconnected, dispersed cells secrete extracellular matrix for support of other tissues/organs Extracellular matrix (ECM) is composed of protein fibers: Collagen Elastin 2 types of Connective Tissue: Loose – less ECM; soft, fluid-like ECM (collagen and Chondrocytes Dense – more ECM; more rigid, structural support. elastin fibers) Animal Anatomy Connective Tissue Blood is connective tissue? Disconnected, dispersed cells secrete extracellular matrix for support of other tissues/organs Extracellular matrix (ECM) White blood cells is composed of protein fibers: Collagen Blood Plasma Elastin Red blood cells 2 types of Connective Tissue: Loose – less ECM; soft, fluid-like Dense – more ECM; more rigid, structural support. Animal Anatomy Nervous Tissue Neuron Transmits long-range signals throughout the body. Coordinates body movement and secretion Processes sensory signals and body responses 2 cell types: Neurons – send/receive Astrocytes signals as electrical impulses Glia – provide support and protection for neurons Oligodendrocytes / Schwann Cells Animal Anatomy Nervous Tissue neurotransmitter Transmits long-range A chemical synapse: signals throughout the body. Coordinates body movement and secretion sodium and axonal boutons calcium ions Processes sensory signals and body responses 2 cell types: dendritic Neurons – send/receive spines signals as electrical impulses Glia – provide support and protection for neurons 1 µm Animal Anatomy Nervous Tissue neurotransmitter Transmits long-range A chemical synapse: signals throughout the body. Coordinates body movement and secretion sodium and axonal boutons calcium ions Processes sensory signals and body responses 2 cell types: dendritic Neurons – send/receive spines signals as electrical impulses Glia – provide support and protection for neurons 1 µm Animal Anatomy Muscle Tissue Generates force for body movement and movement of material through internal organs Contraction based on movement of motor proteins relative to protein fibers. Animal Anatomy Smooth muscle: no regular arrangement of thick and thin filaments Muscle Tissue Generates force for body movement and movement of material through internal organs Contraction based on movement of motor proteins relative to Skeletal muscle: alternating bands of thick and thin filaments – “Striated” protein fibers. Muscles Thin filaments – actin Bundle of Muscle fiber Myofibril fibers Muscle tissue muscle fibers (many cells) (one cell, many myofibrils) (many sarcomeres) Thick filaments – myosin fibers Sarcomere 500 nm Light band Dark band Light band Animal Anatomy Muscle Tissue Generates force for body movement and movement of material through internal organs Contraction based on movement of motor proteins relative to protein fibers. Thin filaments – actin fibers Thick filaments – myosin fibers Animal Anatomy Muscle Tissue Generates force for body movement and MODEL FOR ACTIN-MYOSIN INTERACTION movement of material Thick filament through internal organs ATP ATP Myosin head Contraction based on Thin filament Actin movement of motor 1. ATP binds to myosin head. Head releases from thin filament. proteins relative to Pi + ADP protein fibers. 4. ADP released. Cycle is ready to repeat. 2. ATP hydrolyzed. Head pivots, binds to new actin subunit. Thin filaments – actin fibers ADP ADP Pi Thick filaments – myosin 3. Pi released. Head pivots, moving thin filament (power stroke). fibers Animal Anatomy Organs – putting it all together The small intestine is made up of all four types of tissue. Interface between outside and inside the body is composed of epithelial tissue. Peristaltic motion of fluids through the intestine is accomplished with smooth muscle. Muscle activity and secretion release is controlled by nervous tissue. Connective tissue cushions and binds the other tissues together. Organ structure: What is the purpose of the villi -- protrusions from the wall of the intestine? hint: how do they affect the surface area:volume relationship? Fig. 39.7 Animal Anatomy Organs – putting it all together How many tissue types do you see in blood vessels? Animal Physiology Physiology – how the body functions How the organism obtains and uses energy How the organism distributes nutrients How the organism reproduces Controlled by the nervous system and endocrine system Organs and organ systems accomplish body functions Animal Physiology Body Size How does body size affect physiology? Animal Physiology Body Size How does body size affect physiology? Basal metabolic rate heat loss Animal Physiology Body Size How does body size affect physiology? Basal metabolic rate heat loss Adaptations which increase SA:V Animal Physiology Homeostasis – keeping a steady state internal environment Keeps internal body conditions within a narrow range appropriate for life Contrast with external environment Animal Physiology Homeostatic mechanisms Set point – normal range of values for a particular controlled variable genetically determined Examples of variables under homeostatic control in vertebrates: core body temperature blood glucose levels solute balance urea levels O2/CO2 balance pH blood volume/pressure Feedback – regulation of a process by its output or end-product Sensor – something that detects a change in the environment and provides information to the regulatory system (integrator) Integrator – Compares sensor information with the set point Effector – induces a change in the environment Animal Physiology Homeostatic mechanisms Example of a Feedback system: Thermostat Sensor – thermometer Integrator – circuitry in thermostat Effector – radiator switch This is negative feedback. Integrators and effectors always work to return the variable to the set point. Most common feedback type in homeostatic mechanisms. Animal Physiology Thermoregulation Physiological processes are sensitive to temperature. Recall why from BIOL 205? Functional range for most cellular processes is between 0°C and 45°C. Animal Physiology Thermoregulation How does a body obtain or retain heat? Mechanisms of Heat Exchange: Radiation: heat transfer between two objects not in direct contact with each other. Conduction: direct transfer of heat between two objects in contact with each other. Convection: heat transfer between a solid and moving liquid or gas. Evaporation: phase change from liquid to gas causes heat loss. Metabolic activity generates heat! Animal Physiology Thermoregulation red-spotted newt Homeotherms vs. Poikilotherms Rather than try to keep themselves warm, poikilotherms typically drop their metabolic rate when the temperature drops. brown trout Homeotherms regulate their body temperature to stay within a narrow range. graph from wikipedia Animal Physiology Thermoregulation Ectotherm vs. Endotherm These terms refer to how an organism obtains heat. Endotherms generate heat from their own metabolism. Ectotherms get heat from the environment. Lepus americanus Animal Physiology Thermoregulation Homeothermic strategies for retaining heat in a cold environment Increase insulation (erect hair) Constrict blood vessels going to the skin Countercurrent heat exchange Animal Physiology Thermoregulation Countercurrent exchange Heat will flow from sources to sinks Cold environment is the final sink Warmest part of the body is the most metabolically active (often skeletal muscle) Blood carries heat from muscles to surfaces which touch the cold environment Animal Physiology “Hot” fish Thermoregulation Countercurrent exchange “Hot” fish Animal Physiology Thermoregulation Countercurrent exchange Animal Physiology Thermoregulation Countercurrent exchange Fig. 39.16 Animal Physiology Thermoregulation