8 - Animal Structure and Function_ before by pengxuebo

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									Lecture #8 – Introduction to Animal
      Structure and Function



        Images – the two most beautiful cats in the world,
        currently, as kittens and grownups




                                                             1
             Key Concepts
• What separates animals from other
  organisms?
• Introduction to structure and function
  relationships – the implications of being
  multicellular
• Hierarchical organization in animals
• Tissues
• Organ systems
• Bioenergetics and metabolic rates
                                              2
What do all organisms have to do
      to make a living???




           ???
                                   3
What do organisms have to do to
       make a living???




                                  4
What makes an animal an animal?




           ???
                                  5
What makes an animal an animal?




                                  6
  Structure and Function of Animal
              Systems
• Focus on human biology, but will use
  comparative approach
  Comparisons between animals of differing
   levels of complexity
• We will correlate structure with function, at
  all levels of organization
  Important theme in biology
• Start with intro to basic principles
  Then discussions of various organ systems
                                                  7
           Critical Thinking
• Life has been on this
  planet for 3½ billion
  years!                     Table - the geological
                             time scale
• Until about 700 million
  years ago, all organisms
  were______________?



                                                      8
It’s always fun to
     study the
 geological time
scale – it reveals
the history of life
      on earth



  What happened here???



                          9
           Critical Thinking
• Life has been on this planet for 3½ billion
  years!
• Until about 700 million years ago, all
  organisms were




                                                10
Multi-cellularity imposes limitations, too
 • In most multi-cellular organisms, not every
   cell is in contact with the external
   environment
   Multi-cellular organisms develop complex
    morphologies that reflect their environment
   Multi-cellular organisms develop complex
    mechanisms for resource/waste exchange with
    their environment
   We saw these phenomena with plants –
    animals do the same thing
                                             11
           Critical Thinking
• Terrestrial plants use a tight epidermis and
  a waxy cuticle to retain water
• What is the analogous structure in
  terrestrial animals???




                                             12
           Critical Thinking
• Terrestrial plants use a tight epidermis and
  a waxy cuticle to retain water
• What is the analogous structure in
  terrestrial animals???




                                             13
          Critical Thinking
• Most animals (even many aquatic animals)
  urinate. Why???
• Do plants pee???




                                         14
          Critical Thinking
• Most animals (even many aquatic animals)
  urinate. Why???
• Do plants pee???




                                         15
          Critical Thinking
• Most animals (even many aquatic animals)
  urinate. Why???

• Do plants pee???




                                         16
  Constraints On Size And Shape:
  The physical environment affects animal
  evolution – as it does with all organisms

• Simple physics
                                   Images - convergent
  Flight, soil burrowing,         evolution of spindle-
   swimming for speed…             shaped swimmers

• The physical environment
  Dense water or soil, thin air
• Often leads to convergent
  evolution of shape
                                                      17
  Constraints On Size And Shape:
    The necessity of exchange with the
  environment affects animal evolution….

• Resource/waste exchange
  with the environment                Diagram - 2 tissue
• Diffusion at the surface was        layers in Cnidarians

  characteristic of the earliest
  animals
  Limits size
  Limits shape to thin, flat, open
  Limits complexity
  Mostly quite simple animals                           18
   Most animals have much more
    complex exchange systems
• Exchange occurs at internal epithelia
• Huge surface area is characteristic
• Fun factoids from humans:
   Lungs have 100 m2 of surface area (about ½ as big as
    room)
   Small intestine has surface area of a tennis court
   80 km of tubules in a single kidney
   100,000 km of blood vessels = almost 3x circumference
    of the earth
                                                      19
          Critical Thinking
• How on earth do such large surface areas
  fit into our bodies???




                                         20
                  Critical Thinking
• How on earth do such large surface areas
  fit into our bodies???




  Micrographs - lung and intestinal tissues




                                              Small Intestine Tissue   21
 Exchange with environment is not
     direct for most animals
• Body is covered with waterproof surface
• Complex organ systems exchange
  materials
• Organ systems are linked together, but not
  usually directly
• Most organ systems are separated by
  interstitial fluid = a water-based solution
  that surrounds all cells in the animal body
• Transport occurs through the interstitial
  fluid                                       22
Indirect exchange   Diagram - organization of organ
                    systems showing indirect exchange
between organism    through the interstitial fluid; same
and environment,    diagram on #29

   and between
  organ systems




                                                           23
           Critical Thinking
• Do nutrients leap from our breakfast cereal
  to our cells???
• Why do animals need nutrients anyways???




                                          24
           Critical Thinking
• Do nutrients leap from our breakfast cereal
  to our cells???
• Why do animals need nutrients anyways???




                                          25
           Critical Thinking
• Do nutrients leap from our breakfast cereal
  to our cells???
• Why do animals need nutrients anyways???




                                          26
 Exchange with environment is not
    direct for complex animals
• Body is covered with waterproof surface
• Complex organ systems exchange
  materials
• Organ systems are linked together, but not
  usually directly
• Organ systems are separated by
  interstitial fluid = a water-based solution
  that surrounds all cells in the animal body
• Transport occurs through the interstitial
  fluid                                       27
Indirect exchange
  between organ
  systems occurs
 via the interstitial
        fluid

one big exception:
  the Malphigian
excretory tubules
   in insects are
directly connected
  to the digestive
        tract           28
  All complex
organisms have
                            Diagram - cells - organism in a zebra
 a hierarchical
  organization
  •   Cells
  •   Tissues
  •   Organs
  •   Organ systems
  •   Organism

Form Reflects Function!!!
                                                                    29
           Critical Thinking
• Think of your heart, or this zebra’s – how
  are structure and function related???




                                               30
           Critical Thinking
• Think of your heart, or this zebra’s – how
  are structure and function related???




                                               31
 Form and function are correlated
  from cells  whole organism
• We learned about cells in 111….
  Cells
  Tissues
  Organs
  Organ systems
  Organism



                                    32
       Four major tissue types –
                read more in text




Diagram – tissue types




                                    33
          Epithelial Tissues
• Sheets of cells that cover the body surfaces
  and line many of the internal organs
• Base of epithelial tissue is attached to a
  basement membrane
• The free (exposed) surface has cells that
  are either cuboidal, columnar or squamous
  (tile shaped)
• Shape reflects function!
• Some epithelia waterproof, some leak,
  some secrete, some slough off….            34
Epithelial
 tissues        Diagram – sub-types of epithelial tissues

Which do you
  think are
waterproof???
    Which
  leaky???
    Which
 secrete???
Which slough
    off???
                                                            35
         Connective Tissues
• Cells held in a fibrous or fluid extra-cellular
  matrix
  Matrix generally secreted by the cells
• Many types and sub-types of connective
  tissue
  Loose – bind and shape
  Adipose – store fat
  Fibrous – strong connections
  Cartilage – cushions
  Bone – support system
  Blood – connects tissues to resources        36
          Critical Thinking
• What makes the “bones” of plants???




                                        37
          Critical Thinking
• What makes the “bones” of plants???




                                        38
          Critical Thinking
• How about the blood???




                              39
          Critical Thinking
• What makes the “blood” of plants???




                                        40
            Muscle Tissue
• Composed of cells that can contract
• Skeletal = enable movement, attached to
  bones by tendons
  Voluntary = under conscious nervous system
   control
• Cardiac = forms the heart
  Involuntary
• Smooth or visceral = surround the digestive
  tract, other organs
  Involuntary
                                                41
           Nervous Tissue
• Transmits messages from one part of
  body to another
• Nerve cells have a central cell body +
  appendages that carry messages toward
  or away from the cell (dendrites/axons)
• Appendages may be a meter long in
  humans!


                                            42
           Critical Thinking
• Do all animal tissue types have directly
  analogous tissue types in plants???
• Epithelial???
• Connective???
• Muscle???
• Nervous???


                                             43
           Critical Thinking
• Do all animal tissue types have directly
  analogous tissue types in plants???
• Epithelial –
• Connective –
• Muscle –
• Nervous –


                                             44
                  Organs
• Composed of two or more types of tissues
  organized into a functional unit
• Tissues are often in layers, or they may be
  integrated throughout the organ
  Stomach has layers of epithelial, connective,
   muscle, connective
  Skin has layers of epithelial, connective,
   muscle
  All tissues have blood vessels and nerve
   tissues integrated
                                                   45
  Most animals have body cavities
• These are fluid filled spaces that cushion
  and suspend organs
• Sometimes they also give the body shape
• In vertebrates, many organs are held in
  place in the body cavity by layers of
  connective tissues (mesenteries) and
  sheets of muscle (diaphragm)

            Diagram – body cavities

                                               46
           Organ Systems:
groups of related organs that maintain various
                body functions
• Complex organ systems are present in all
  higher animals
• All organ systems are interdependent
  Functions are coordinated (ex: digestive +
   vascular)
• All systems work together to maintain
  homeostasis (~constant internal conditions,
  more on this later)                      47
                    Organ Systems:
  most complex animals have 11 major organ
systems – image search for a table like this one


      Table – all the organ systems found in a complex animal




                                                                48
     Diagrams – closeups of the major organ
     systems; similar diagrams on next 4 slides




Digestive                                         Circulatory
                                                          49
Respiratory   Immune
                   50
Excretory   Endocrine
                    51
Reproductive   Nervous

                   52
 Skeletal and
                Muscular
Integumentary
                           53
Organ systems       Diagram – summary of organ systems

are integrated in
 both structure
 and function to
  produce the
whole organism




                                                         54
  Bioenergetic Principles Regulate
         Organism Activity
• Bioenergetics: the flow of energy through
  the animal
  Controlled by energy sources vs. energy uses
   (food intake vs. metabolism)
• Metabolic rates vary based on size, activity
  levels, homeostasis strategy and
  thermoregulation strategy
  Important selection pressures include the
   physical environment and interactions with
   other organisms
                                                55
                 Diagram – bioenergetics in an organism
  Energy
management:
food supplies
energy to fund
 metabolism,
  maintain
homeostasis,
 and support
   activity

                                                      56
  Influences on Metabolic Rate
• Body size
  Inverse relationship between size and
   metabolic rate per unit mass
  Evidence is clear; explanation is unclear
• Activity level
• Homeostasis strategy
  It “costs” more to regulate
• Thermoregulation strategy
                                               57
  Influences on Metabolic Rate
• Body size
  Inverse relationship between size and
   metabolic rate per unit mass
  Evidence is clear; explanation is unclear
• Activity level
• Homeostasis strategy
  It “costs” more to regulate
• Thermoregulation strategy
                                               58
               Homeostasis
• Maintenance of constant internal
  conditions (actually, within a range of
  tolerance)
• Various control systems regulate
  temperature, salt concentrations, water
  content, pH, blood sugar, etc
• Most control systems rely on negative
  feedback loops = the results of a process
  inhibit that process
  process is self limiting
                                              59
 Most organisms regulate at least some
components of their internal environment


   Diagram – homeostasis




                                      60
              Homeostasis
• Maintenance of constant internal
  conditions (actually, within a range of
  tolerance)
• Various control systems regulate
  temperature, salt concentrations, water
  content, pH, blood sugar, etc
• Most control systems rely on negative
  feedback loops = the results of a process
  inhibit that process
  Process is self limiting
                                              61
Feedback Loops:   Diagram – a mechanical
                  representation of a negative
thermostats and   feedback loop

 furnaces are a
    non-living
    example




                                                 62
Many similar strategies for regulation of
 blood chemistry, blood sugar, body
       temperature, etc etc etc

  Diagrams – representations of
  biological negative feedback
  loops




                                        63
   Homeostasis is dynamic….
• All feedback loops are constantly monitored
  and levels are fluctuating within range
• Not all animals maintain stable internal
  conditions
  Regulators expend metabolic energy to
   maintain stability
  Conformers don’t – internal values vary with
   external conditions
  Some animals regulate some conditions,
   conform to others
                                                  64
  Influences on Metabolic Rate
• Body size
  Inverse relationship between size and
   metabolic rate per unit mass
  Evidence is clear; explanation is unclear
• Activity level
• Homeostasis strategy
  It “costs” more to regulate
• Thermoregulation strategy
                                               65
          Thermoregulation
• All biochemical processes are sensitive to
  temperature
• Extreme temperatures can denature
  proteins or alter membrane function
• Animals regulate their internal temperature
  to maintain metabolic function
• Two main strategies have emerged
  Ecothermy
  Endothermy                               66
          Thermoregulation
• Ectothermic animals gain heat from the
  surrounding environment
• Most invertebrates, fishes, amphibians
  and reptiles
  Low metabolic rate when cold
  Not always able to be active
  Behavior is often used to regulate body
   temperature


                                             67
          Critical Thinking
• Are ectothermic animals cold blooded???




                                            68
          Critical Thinking
• Are ectothermic
  animals cold
                    Graph – body temp vs. environmental
  blooded???        temp in ectotherms vs. endotherms




                                                    69
           Critical Thinking
• What are the costs and benefits of
  ectothermy???




                                       70
           Critical Thinking
• What are the costs and benefits of
  ectothermy???




                                       71
           Thermoregulation
• Endothermic animals use energy to
  maintain a constant body temperature
• Primarily mammals and birds
  High metabolic rate generates waste heat that
   keeps the body warm
  Most endotherms also gain some heat from
   their surroundings or behaviors
  Some endotherms vary body temperature by
   season or time of day (hibernation, estivation,
   diurnation)
                                                72
           Critical Thinking
• What are the costs and benefits of
  endothermy???




                                       73
           Critical Thinking
• What are the costs and benefits of
  endothermy???




                                       74
Most endotherms are terrestrial
• Moving on land requires more energy than
  moving in water (water supports)
• Land T fluctuates more than water T (high
  heat capacity of H2O)
• The development of endothermy was an
  important adaptation to the colonization of
  land
• Many terrestrial animals are ectothermic,
  but few aquatic animals are endothermic
                                            75
Always
active



            Graph – body temp vs. environmental
            temp in ectotherms vs. endotherms




Slow
when it’s
cold


                                            76
   Both endo’s and ecto’s have many
strategies to regulate body temperature
• Insulation
• Adjusting the rate of heat exchange with
  the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate


                                             77
Diagram – adipose tissue as insulation




                                         78
 Many strategies to regulate body
           temperature
• Insulation
• Adjusting the rate of heat exchange with
  the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate


                                             79
  Adjusting the rate of heat exchange
         with the environment
• Constriction or dilation of surface blood
  vessels
• Raising of fur or feathers
• Fat accumulation
• Countercurrent heat exchange




                                              80
          Critical Thinking
• How would changing blood vessel diameter
  change the rate of heat exchange???




                                        81
          Critical Thinking
• How would changing blood vessel diameter
  change the rate of heat exchange???




                                        82
  Adjusting the rate of heat exchange
         with the environment
• Constriction or dilation of surface blood
  vessels
• Raising of fur or feathers
• Fat accumulation
• Countercurrent heat exchange




                                              83
           Critical Thinking
• How would raising the fur or feathers
  change the rate of heat exchange???




                                          84
           Critical Thinking
• Why would raising the fur or feathers
  change the rate of heat exchange???




               Image – fluffed bird




                                          85
  Adjusting the rate of heat exchange
         with the environment
• Constriction or dilation of surface blood
  vessels
• Raising of fur or feathers
• Fat accumulation
• Countercurrent heat exchange




                                              86
Countercurrent Exchange: arterial blood is warmer
 (comes from body core); warms adjacent venous
               blood in extremities



          Diagram – countercurrent blood
          flow in bird’s leg and dolphin’s fin




                                                 87
   Adjusting the rate of heat exchange
          with the environment
• Some ectotherm fishes
  maintain higher
                           Diagram – countercurrent flow
  temperatures in their    in deep muscles of fish
  deep swimming muscles
  with a heat exchanging
  pattern of blood flow
  Increases aerobic
   respiration (thus ATP
   production) in those
   muscles
  Partial endotherms                                 88
 Many strategies to regulate body
           temperature
• Insulation
• Adjusting the rate of heat exchange with
  the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate


                                             89
Sweating, panting,
 wetting….often
    linked to
  behaviors….




   Images – animals panting and spraying




                                           90
 Many strategies to regulate body
           temperature
• Insulation
• Adjusting the rate of heat exchange with
  the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate


                                             91
               Behavior
• Moving to shade/sun
• Moving into/out of water     Image – dragonfly
                               positioned for
• Restricting activity to      minimum solar
                               exposure
  night/day
• Regulating body posture to
  manage solar exposure
• Migrating
• Social behavior to share
  heat (bees)                                      92
 Many strategies to regulate body
           temperature
• Insulation
• Adjusting the rate of heat exchange with
  the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate


                                             93
      Adjusting metabolic rate
• Increases or decreases in muscular activity
  (shivering, active motion)
• Acclimation – many animals adjust to temperature
  changes throughout the seasons by changing
  enzyme type and quantity, altering lipids to keep
  membranes fluid
• Torpor – some animals react to predictable
  temperature and food supply fluctuations by
  entering a state of reduced metabolism
  (hibernation, etc)
   Daylength is the likely trigger
                                                94
Graph – change in a moth’s thorax
temperature with pre-flight shivering




                                        95
      Adjusting metabolic rate
• Increases or decreases in muscular activity
  (shivering, active motion)
• Acclimation – many animals adjust to temperature
  changes throughout the seasons by changing
  enzyme type and quantity, altering lipids to keep
  membranes fluid
• Torpor – some animals react to predictable
  temperature and food supply fluctuations by
  entering a state of reduced metabolism
  (hibernation, etc)
   Daylength is the likely trigger for seasonal torpor
                                                          96
REVIEW: Both endo’s and ecto’s have
  many strategies to regulate body
            temperature
• Insulation
• Adjusting the rate of heat exchange with
  the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate

                                             97
     REVIEW: Key Concepts
• What separates animals from other
  organisms?
• Introduction to structure and function
  relationships – the implications of being
  multicellular
• Hierarchical organization in animals
• Tissues
• Organ systems
• Bioenergetics and metabolic rates
                                              98

								
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