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+ Mrs. Valdes AP Biology Chapter 40: Basic Principles of Form and Function.

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Presentation on theme: "+ Mrs. Valdes AP Biology Chapter 40: Basic Principles of Form and Function."— Presentation transcript:

1 + Mrs. Valdes AP Biology Chapter 40: Basic Principles of Form and Function

2 + Overview: Diverse Forms, Common Challenges Anatomy: study of biological form of organism Physiology: study of biological functions organism performs Comparative study of animals reveals form and function closely correlated… you know this!

3 + Concept 40.1: Animal form and function correlated at ALL levels of organization Body plans evolved and determined by genome Physical Constraint: ability to perform certain actions depends on animal ’ s shape, size, and environment Evolutionary convergence reflects different species ’ adaptations to similar environmental challenge Physical laws impose constraints on animal size and shape Environment Exchange: animal ’ s size and shape directly affect how it exchanges energy and materials with its surroundings occurs as substances dissolved in aqueous medium diffuse and are transported across cells ’ plasma membranes Single-celled: protist living in water has sufficient surface area of plasma membrane to service its entire volume of cytoplasm Multicellular organisms: some have sac body plan; body walls only two cells thick, facilitating diffusion of materials More complex organisms: highly folded internal surfaces for exchanging materials Vertebrates: space between cells filled with interstitial fluid allows for movement of material into and out of cells A complex body plan helps animal in variable environment to maintain stable internal environment

4 + Cells > Tissues > Organs > Organ System Tissues classified into four main categories: epithelial, connective, muscle, and nervous Hierarchical Organization of Body Plans

5 + Epithelial Tissue Epithelial tissue: covers outside of body and lines organs and cavities within body contains cells closely joined shape of epithelial cells: cuboidal (like dice) columnar (like bricks on end) squamous (like floor tiles) arrangement of epithelial cells: simple (single cell layer) stratified (multiple tiers of cells) pseudostratified (a single layer of cells of varying length)

6 + Connective Tissue mainly binds and supports other tissues contains sparsely packed cells scattered through extracellular matrix matrix consists of fibers in liquid, jellylike, or solid foundation Types of connective tissue fiber: Collagenous fibers provide strength and flexibility Elastic fibers stretch and snap back to original length Reticular fibers join connective tissue to adjacent tissues Connective cells: Fibroblasts: secrete the protein of extracellular fibers Macrophages: involved in immune system Fibers and foundation combine to form six major types of connective tissue: Loose connective tissue: binds epithelia to underlying tissues; holds organs in place Cartilage: strong and flexible support material Fibrous connective tissue: found in tendons (attach muscles to bones) and ligaments (connect bones at joints) Adipose tissue: stores fat for insulation and fuel Blood: composed of blood cells and cell fragments in blood plasma Bone: mineralized and forms skeleton

7 + Fig. 40-5c Connective Tissue Collagenous fiber Loose connective tissue Elastic fiber 120 µm Cartilage Chondrocytes 100 µm Chondroitin sulfate Adipose tissue Fat droplets 150 µm White blood cells 55 µm Plasma Red blood cells Blood Nuclei Fibrous connective tissue 30 µm Osteon Bone Central canal 700 µm

8 + Fig. 40-5d Collagenous fiber 120 µm Elastic fiber Loose connective tissue

9 + Fig. 40-5e Nuclei Fibrous connective tissue 30 µm

10 + Fig. 40-5f Osteon Central canal Bone 700 µm

11 + Fig. 40-5g Chondrocytes Chondroitin sulfate Cartilage 100 µm

12 + Fig. 40-5h Fat droplets Adipose tissue 150 µm

13 + Fig. 40-5i White blood cells Plasma Red blood cells 55 µm Blood

14 + Muscle Tissue consists of long cells called muscle fibers, which contract in response to nerve signals Types: Skeletal muscle: or striated muscle, responsible for voluntary movement Smooth muscle: responsible for involuntary body activities Cardiac muscle: responsible for contraction of the heart

15 + Fig. 40-5j Muscle Tissue 50 µm Skeletal muscle Multiple nuclei Muscle fiber Sarcomere 100 µm Smooth muscle Cardiac muscle Nucleus Muscle fibers 25 µm Nucleus Intercalated disk

16 + Fig. 40-5k Skeletal muscle Multiple nuclei Muscle fiber Sarcomere 100 µm

17 + Fig. 40-5l Smooth muscle Nucleus Muscle fibers 25 µm

18 + Fig. 40-5m NucleusIntercalated disk Cardiac muscle 50 µm

19 + Nervous Tissue senses stimuli and transmits signals throughout the animal Contains: Neurons: nerve cells, that transmit nerve impulses Glial cells, or glia: help nourish, insulate, and replenish neurons

20 + Coordination and Control Depend on endocrine system and nervous system Endocrine system: transmits hormones to receptive cells throughout body via blood hormone may affect one or more regions throughout body Hormones relatively slow acting, but can have long-lasting effects Nervous system: transmits information between specific locations information conveyed depends on a signal ’ s pathway NOT type of signal Nerve signal transmission is FAST Nerve impulses received by neurons, muscle cells, and endocrine cells

21 + Concept 40.2: Feedback control loops maintain internal environment in many animals Animals manage internal environment by regulating or conforming to external environment Regulator: uses internal control mechanisms to moderate internal change in face of external, environmental fluctuation Conformer: allows internal condition to vary with certain external changes

22 + Homeostasis Maintain “steady state ” or internal balance regardless of external environment Humans: body temperature, blood pH, and glucose concentration Mechanisms: moderate changes in internal environment For given variable, fluctuations above/below set point serve as stimulus that are detected by sensor and trigger response response returns the variable to the set point Feedback Loops: Negative feedback Helps return variable to either normal range or a set point Most homeostatic control systems function by negative feedback, where buildup of the end product shuts the system off Positive feedback occur in animals, but do not usually contribute to homeostasis Set points and normal ranges change with age or show cyclic variation Acclimatization: homeostasis can adjust to changes in external environment

23 + Concept 40.3: Homeostatic processes for thermoregulation involve form, function, & behavior Thermoregulation: process by which animals maintain internal temperature within tolerable range Endotherm: animal generates heat by metabolism; Ex: birds and mammals active at a greater range of external temperatures more energetically expensive Homeotherm: body temperature relatively constant Ectotherm: animal gains heat from external sources; include most invertebrates, fishes, amphibians, and non-avian reptiles tolerate greater variation in internal temperature, while endotherms are Poikilotherm: body temperature varies with its environment,

24 + Balancing Heat Loss & Gain Organisms exchange heat by : conduction convection radiation evaporation Heat regulation in mammals involves integumentary system: skin hair nails General adaptations: Insulation Circulatory adaptations Cooling by evaporative heat loss Behavioral responses Adjusting metabolic heat production

25 + Insulation Major thermoregulatory adaptation in mammals and birds Ex: Skin, feathers, fur, and blubber Reduce heat flow between an animal and its environment

26 + Regulation of blood flow near body surface significantly affects thermoregulation Many endotherms and some ectotherms alter amount of blood flowing between body core and skin Vasodilation: blood flow in skin increases  increase heat loss Vasoconstriction: blood flow in skin decreases  decrease heat loss Countercurrent exchange: important mechanism for reducing heat loss; transfer heat between fluids flowing in opposite directions arrangement of blood vessels in marine mammals and birds Some bony fishes and sharks Many endothermic insects use to maintain high temperature in thorax Circulatory Adaptations

27 + Cooling by Evaporative Heat Loss Animals lose heat through evaporation of water in sweat Panting increases cooling effect in birds and many mammals Sweating/bathing moistens skin, helping cool animal down

28 + Endotherms and ectotherms use behavioral responses to control body temperature Terrestrial invertebrates have postures to minimize or maximize absorption of solar heat Ex: Dragonfly obelisk to minimize sun exposure Behavioral Responses

29 + Adjusting Metabolic Heat Production Some animals regulate body temperature by adjusting rate of metabolic heat production Heat production increased by muscle activity like moving or shivering Some ectotherms shiver to increase body temperature

30 + Birds and mammals vary insulation to acclimatize to seasonal temperature changes Temps subzero: some ectotherms produce “ antifreeze ” compounds to prevent ice formation in their cells Thermoregulation: controlled by hypothalamus Hypothalamus: triggers heat loss or heat generating mechanisms Fever: result of change to set point for biological thermostat Acclimatization in Thermoregulation

31 + Concept 40.4: Energy requirements related to animal size, activity, and environment Bioenergetics: overall flow and transformation of energy in an animal determines how much food animal needs relates to animal ’ s size, activity, and environment Energy Allocation and Use Animals harvest chemical energy from food Food  ATP  Cellular Work After needs of staying alive met, remaining food molecules used in biosynthesis Biosynthesis: includes body growth and repair synthesis of storage material such as fat production of gametes

32 + Metabolic rate: amount of energy animal uses in unit of time One way to measure: determine amount of oxygen consumed OR carbon dioxide produced affected by many factors besides whether an animal is an endotherm or ectotherm size activity Basal metabolic rate (BMR): metabolic rate of endotherm at rest at “comfortable ” temperature Standard metabolic rate (SMR): metabolic rate of ectotherm at rest at specific temperature Both rates assume nongrowing, fasting, and nonstressed animal Ectotherms have lower metabolic rates than endotherms of comparable size Quantifying Energy Use

33 + Size and Metabolic Rate Metabolic rate per gram inversely related to body size among similar animals Higher metabolic rate of smaller animals  higher oxygen delivery rate, breathing rate, heart rate, and greater (relative) blood volume, compared with a larger animal

34 + Maximum metabolic rate animal can sustain inversely related to duration of the activity Activity and Metabolic Rate

35 + Different species use energy and materials in different ways depending on environment Use of energy is partitioned to BMR (or SMR), activity, thermoregulation, growth, and reproduction Energy Budgets

36 + Torpor and Energy Conservation Torpor: physiological state in which activity is low and metabolism decreases enables animals to save energy while avoiding difficult and dangerous conditions Hibernation: long-term torpor; adaptation to winter cold and food scarcity Estivation: summer torpor; enables animals to survive long periods of high temperatures and scarce water supplies Daily torpor: exhibited by many small mammals and birds; seems adapted to feeding patterns

37 + You should now be able to: 1. Distinguish among the following sets of terms: collagenous, elastic, and reticular fibers; regulator and conformer; positive and negative feedback; basal and standard metabolic rates; torpor, hibernation, estivation, and daily torpor 2. Relate structure with function and identify diagrams of the following animal tissues: epithelial, connective tissue (six types), muscle tissue (three types), and nervous tissue 3. Compare and contrast the nervous and endocrine systems 4. Define thermoregulation and explain how endotherms and ectotherms manage their heat budgets 5. Describe how a countercurrent heat exchanger may function to retain heat within an animal body 6. Define bioenergetics and biosynthesis 7. Define metabolic rate and explain how it can be determined for animals

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