1. Chapter 40
Animal form and function

2. Hierarchical Organization of Body Plans
Most animals are composed of specialized cells organized into tissues that have different functions
Tissues make up organs, which together make up organ systems
Some organs, such as the pancreas, belong to more than one organ system

3. Figure 40.3 Mouth Gastrovascular cavity Exchange Exchange Exchange
Figure 40.3 Direct exchange with the environment
0.1 mm
1 mm
(a)
An amoeba, a single-celled
organism
(b)
A hydra, an animal with two
layers of cells

4. Figure 40.4 External environment Food CO2 O2 Mouth Animal body
Respiratory
system
250 µm
Lung tissue (SEM)
Interstitial
fluid
Heart
Nutrients
Cells
Circulatory
system
Figure 40.4 Internal exchange surfaces of complex animals
Digestive
system
Excretory
system
100 µm
50 µm
Lining of small
intestine (SEM)
Anus
Blood vessels in
kidney (SEM)
Unabsorbed
matter (feces)
Metabolic waste
products (nitrogenous waste)

5. Table 40.1
Table 40.1 Organ systems in mammals

6. Structure and Function in Animal Tissues
Different tissues have different structures that are suited to their functions
Tissues are classified into four main categories: epithelial, connective, muscle, and nervous

7. Epithelial Tissue
Epithelial tissue covers and lines organs and cavities
cells that are closely joined
Named by:
1. shape of cells
cuboidal (like dice),
columnar (like bricks
squamous (like floor tiles)
2. number of layers
simple-one layer
stratified- many layers

9. Connective Tissue Blood Loose connective tissue Cartilage
Figure 40.5b
Connective Tissue
Blood
Loose connective tissue
Plasma
Collagenous fiber
White
blood
cells
55 µm
120 µm
Red blood cells
Cartilage
Elastic fiber
Fibrous connective tissue
Chondrocytes
100 µm
30 µm
Figure 40.5b Exploring structure and function in animal tissues (part 2: connective)
Chondroitin sulfate
Bone
Adipose tissue
Nuclei
Central
canal
Fat droplets
700 µm
150 µm
Osteon

10. Matrix consists of fibers in a liquid, jellylike, or solid foundation
Connective Tissue
Binds and supports other tissues
Few cells scattered throughout an extracellular matrix
Connective tissue contains cells, including
Fibroblasts that secrete the protein of extracellular fibers
Macrophages that are involved in the immune system
Matrix consists of fibers in a liquid, jellylike, or solid foundation
three types of connective tissue fiber, all made of protein
Collagenous fibers provide strength and flexibility
Reticular fibers join connective tissue to adjacent tissues
Elastic fibers stretch and snap back to their original length

11. six major types of connective tissue
Loose connective tissue binds epithelia to underlying tissues and holds organs in place
Fibrous connective tissue is found in tendons, which attach muscles to bones, and ligaments, which connect bones at joints
Bone is mineralized and forms the skeleton
Adipose tissue stores fat for insulation and fuel
Blood is composed of blood cells and cell fragments in blood plasma
Cartilage is a strong and flexible support material

12. Muscle Tissue
responsible for body movement
cells consist of filaments of the proteins actin and myosin, which slide past each other to shorten the muscle (contract)
It is divided in the vertebrate body into three types
Skeletal muscle, or striated muscle, is responsible for voluntary movement
Smooth muscle is responsible for involuntary body activities
Cardiac muscle is responsible for contraction of the heart

13. Muscle Tissue Skeletal muscle Smooth muscle Cardiac muscle Nuclei
Figure 40.5c
Muscle Tissue
Skeletal muscle
Nuclei
Muscle
fiber
Sarcomere
100 µm
Smooth muscle
Cardiac muscle
Figure 40.5c Exploring structure and function in animal tissues (part 3: muscle)
Nucleus
Muscle
fibers
25 µm
Nucleus
Intercalated
disk
25 µm

14. Sends receives integrates nerve signals Makes up the nervous system
Nervous Tissue
Sends receives integrates nerve signals
Makes up the nervous system
Rapid coordination, movement.
Nervous tissue contains
Neurons, or nerve cells, that transmit nerve impulses
Glial cells, or glia, support cells
Sensory neurons, motor neurons, interneurons

15. Nervous Tissue Neurons Glia 15 µm Glia Neuron: Dendrites Cell body
Figure 40.5d
Nervous Tissue
Neurons
Glia
15 µm
Glia
Neuron:
Dendrites
Cell body
Axons of
neurons
Axon
40 µm
Figure 40.5d Exploring structure and function in animal tissues (part 4: nervous)
Blood
vessel
(Fluorescent LM)
(Confocal LM)

16. Coordination and Control
The endocrine system transmits chemical signals called hormones to receptive cells throughout the body via blood
A hormone may affect one or more regions throughout the body
Hormones are relatively slow acting, but can have long-lasting effects
The nervous system transmits information between specific locations
The information conveyed depends on a signal’s pathway, not the type of signal
Nerve signal transmission is very fast

17. Figure 40.6 Signaling in the endocrine and nervous systems Axons
(a) Signaling by hormones
(b) Signaling by neurons
STIMULUS
STIMULUS
Endocrine
cell
Cell body
of neuron
Nerve
impulse
Axon
Hormone
Signal travels
everywhere.
Signal travels
to a specific
location.
Blood
vessel
Nerve
impulse
Figure 40.6 Signaling in the endocrine and nervous systems
Axons
Response
Response

18. Feedback control maintains the internal environment
animals manage their internal environment by either regulating or conforming

19. (temperature conformer) Ambient (environmental)
Figure 40.7 40
River otter (temperature regulator) 30
Body temperature (C) 20
Largemouth bass
(temperature conformer) 10
Figure 40.7 The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer 10 20 30 40
Ambient (environmental)
temperature (C)

20. Homeostasis
Organisms use homeostasis to maintain a “steady state” or internal balance regardless of external environment
In humans, body temperature, blood pH, and glucose concentration are each maintained at a constant level

21. Mechanisms of Homeostasis
For a given variable, fluctuations above or below a set point serve as a stimulus; these are detected by a sensor and trigger a response
The response returns the variable to the set point
Positive and negative feedback

22. (-) (-) Thermostat turns heater off. Room temperature increases.
Figure 40.8
Thermostat turns
heater off.
Room temperature
increases.
Room temperature
decreases.
(-)
ROOM
TEMPERATURE
AT 20C (set point)
(-)
(Error signal)
Figure 40.8 A nonliving example of temperature regulation: control of room temperature
Room temperature
increases.
Room temperature
decreases.
Thermostat
turns heater on.
(compensatory response)
(Effector)

23. Animation: Negative Feedback

24. Animation: Positive Feedback

25. Feedback Control Circadian rhythms
Homeostasis in animals relies largely on negative feedback, which helps to return a variable to a normal range
Positive feedback amplifies a stimulus and does not usually contribute to homeostasis in animals
Set points and normal ranges can change with age or show cyclic variation
In animals and plants, a circadian rhythm governs physiological changes that occur roughly every 24 hours

26. Melatonin concentration Core body temperature (C)
Figure 40.9
Body
temperature
Melatonin
concentration
37.1 60
Melatonin concentration
in blood (pg/mL)
Core body temperature (C)
36.9 40
36.7 20
36.5 2 PM 6 PM 10 PM 2 AM 6 AM 10 AM
Time of day
(a)
Variation in core body temperature and melatonin
concentration in blood
Start of
melatonin secretion
Midnight
Lowest
heart rate
Greatest
muscle
strength
Figure 40.9 Human circadian rhythm
Lowest body
temperature
6 PM
6 AM
Most rapid
rise in blood
pressure
Fastest
reaction time
Highest risk
of cardiac arrest
Noon
(b) The human circadian clock

27. Homeostatic processes for thermoregulation
Thermoregulation - animals maintain an internal temperature within a tolerable range
Endothermic animals generate heat by metabolism; birds and mammals are endotherms
Ectothermic animals gain heat from external sources; ectotherms include most invertebrates, fishes, amphibians, and nonavian reptiles
Endotherms maintain a stable body temperature even during large fluctuations in temperature
ectotherms tolerate greater variation in internal temperature
The body temperature of a poikilotherm varies with its environment
The body temperature of a homeotherm is relatively constant

28. Variation in Body Temperature
The relationship between heat source and body temperature is not fixed (that is, not all poikilotherms are ectotherms)

29. Circulatory Adaptations
Regulation of blood flow near the body surface significantly affects thermoregulation
Many endotherms and some ectotherms can alter the amount of blood flowing between the body core and the skin
In vasodilation, blood flow in the skin increases, facilitating heat loss
In vasoconstriction, blood flow in the skin decreases, lowering heat loss

30. Adjusting Metabolic Heat Production
Thermogenesis is the adjustment of metabolic heat production to maintain body temperature
Thermogenesis is increased by muscle activity such as moving or shivering
Nonshivering thermogenesis takes place when hormones cause mitochondria to increase their metabolic activity
Some ectotherms can also shiver to increase body temperature

31. Time from onset of warm-up (min)
Figure 40.15
PREFLIGHT
PREFLIGHT
WARM-UP
FLIGHT 40
Thorax
Thorax 35
Temperature (C)
Abdomen 30
Abdomen
Figure Preflight warm-up in the hawkmoth 25 2 4
Time from onset of warm-up (min)

32. Acclimatization in Thermoregulation
Birds and mammals can vary their insulation to acclimatize to seasonal temperature changes
When temperatures are subzero, some ectotherms produce “antifreeze” compounds to prevent ice formation in their cells

33. Physiological Thermostats and Fever
Thermoregulation in mammals is controlled by a region of the brain called the hypothalamus
The hypothalamus triggers heat loss or heat generating mechanisms
Fever, a response to some infections, reflects an increase in the normal range for the biological thermostat
Some ectothermic organisms seek warmer environments to increase their body temperature in response to certain infections

34. Thermostat in hypothalamus activates cooling mechanisms.
Figure 40.17
Thermostat in
hypothalamus
activates cooling
mechanisms.
Response: Blood
vessels in skin dilate.
Response:
Sweat
Body temperature
increases.
Body temperature
decreases.
NORMAL BODY
TEMPERATURE
(approximately
36–38C)
Body temperature
increases.
Body temperature
decreases.
Figure The thermostatic function of the hypothalamus in human thermoregulation
Response: Shivering
Response: Blood
vessels in skin
constrict.
Thermostat in
hypothalamus
activates warming
mechanisms.

35. Quantifying Energy Use
Metabolic rate is the amount of energy an animal uses in a unit of time
Metabolic rate can be determined by
An animal’s heat loss
The amount of oxygen consumed or carbon dioxide produced
Measuring energy content of food consumed and energy lost in waste products

36. Figure 40.19
Figure Measuring the rate of oxygen consumption by a swimming shark

37. Minimum Metabolic Rate and Thermoregulation
Basal metabolic rate (BMR) is the metabolic rate of an endotherm at rest at a “comfortable” temperature
Standard metabolic rate (SMR) is the metabolic rate of an ectotherm at rest at a specific temperature
Both rates assume a nongrowing, fasting, and nonstressed animal
Ectotherms have much lower metabolic rates than endotherms of a comparable size

38. Influences on Metabolic Rate
Metabolic rates are affected by many factors besides whether an animal is an endotherm or ectotherm
Some key factors are age, sex, size, activity, temperature, and nutrition

39. Basal (standard) metabolism Activity
Figure 40.UN01
Adélie penguin
4-kg male
340,000 kcal/yr
Deer mouse
0.025-kg female
4,000 kcal/yr
Ball python
4-kg female
8,000 kcal/yr
Figure 40.UN01 Skills exercise: interpreting pie charts
Key
Basal (standard) metabolism
Activity
Reproduction
Growth
Thermoregulation

40. NORMAL RANGE for internal variable Stimulus: change in Response
Figure 40.UN03
NORMAL RANGE
for internal variable
Response
Stimulus: change in
internal variable
Figure 40.UN03 Summary of key concepts: feedback control
Control center
Sensor