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

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

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. Connective Tissue Loose connective tissue Cartilage Fibrous connective
Fig. 40-5c
Connective Tissue
Collagenous fiber
Loose
connective
tissue
Chondrocytes
Cartilage
120 µm
100 µm
Elastic fiber
Chondroitin
sulfate
Nuclei
Fat droplets
Fibrous
connective
tissue
Adipose
tissue
30 µm
150 µm
Figure 40.5 Structure and function in animal tissues
Osteon
White blood cells
Bone
Blood
700 µm
55 µm
Central canal
Plasma
Red blood
cells

8. Loose connective tissue
Fig. 40-5d
Collagenous fiber
120 µm
Figure 40.5 Structure and function in animal tissues
Elastic fiber
Loose connective tissue

9. Fibrous connective tissue
Fig. 40-5e
Nuclei
30 µm
Figure 40.5 Structure and function in animal tissues
Fibrous connective tissue

10. Bone Osteon 700 µm Central canal Fig. 40-5f
Figure 40.5 Structure and function in animal tissues
Central canal
Bone

11. Cartilage Chondrocytes 100 µm Chondroitin sulfate Fig. 40-5g
Figure 40.5 Structure and function in animal tissues
Chondroitin
sulfate
Cartilage

12. Adipose tissue Fat droplets 150 µm Fig. 40-5h
Figure 40.5 Structure and function in animal tissues
Adipose tissue

13. Blood White blood cells 55 µm Plasma Red blood cells Fig. 40-5i
Figure 40.5 Structure and function in animal tissues
Plasma
Red blood
cells
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. Muscle Tissue Skeletal muscle Cardiac muscle Smooth muscle Multiple
Fig. 40-5j
Muscle Tissue
Multiple
nuclei
Muscle fiber
Sarcomere
Skeletal
muscle
Nucleus
100 µm
Intercalated
disk
50 µm
Cardiac muscle
Figure 40.5 Structure and function in animal tissues
Smooth
muscle
Nucleus
Muscle
fibers
25 µm

16. Skeletal muscle Multiple nuclei Muscle fiber Sarcomere 100 µm
Fig. 40-5k
Multiple
nuclei
Muscle fiber
Sarcomere
Figure 40.5 Structure and function in animal tissues
100 µm
Skeletal muscle

17. Smooth muscle Nucleus Muscle fibers 25 µm Fig. 40-5l
Figure 40.5 Structure and function in animal tissues
25 µm
Smooth muscle

18. Cardiac muscle Nucleus Intercalated disk 50 µm Fig. 40-5m
Figure 40.5 Structure and function in animal tissues
Nucleus
Intercalated
disk
50 µm
Cardiac muscle

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. Circulatory Adaptations
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

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. Behavioral Responses
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

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. Acclimatization in Thermoregulation
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

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. Quantifying Energy Use
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

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

35. Energy Budgets
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

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:
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
Relate structure with function and identify diagrams of the following animal tissues: epithelial, connective tissue (six types), muscle tissue (three types), and nervous tissue
Compare and contrast the nervous and endocrine systems
Define thermoregulation and explain how endotherms and ectotherms manage their heat budgets
Describe how a countercurrent heat exchanger may function to retain heat within an animal body
Define bioenergetics and biosynthesis
Define metabolic rate and explain how it can be determined for animals