Download Animal form and function

Animal form and function
Common problems
 All cells need aqueous environment
 Gas exchange
 Nourishment
 Excrete waste
 Move
Form and function
 Anatomy = form
 Physiology = function
 Examples:
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Capillaries and alveoli: 1 cell thick, allow gas ex.
Muscle cells: long fibers, allow long lever arm
RBC: smooth, round allow flow through vessels
Skin: many cells thick, allow for scrapes without lots of
blood loss
Body plans
 Need: exchange with environment
 Need: aqueous environment for each cell
 Protist: 1 cell: exchange across cell membrane
Mammals
 Simple diffusion?
Adaptations
 Elephant: millions of cells must get glucose and oxygen.
 Aqueous solution for all cells = interstitial fluid
 Increase surface area within organ system by:
 Folds and protrusions
Tissue
 4 types of tissue
 Muscle: contractile
 Nervous: conduct impulses
 Epithelial: lines things, secretion
 Connective: holds things together
Muscle tissue
 Muscle:
 Most abundant tissue
 Smooth, cardiac (desmosomes), skeletal
 Proteins: actin and myosin
 Second messenger: Ca++
 ATP needed for contraction
Nervous tissue
 Nervous
 Excitable, conducts impulses
 Neuron
 CNS: brain and spinal cord PNS
Connective tissue
 Connective tissue: cells in a matrix with proteins
 Blood to bone Matrix: liquid to solid
 Fibers: collagen, elastic, reticular
Epithelial tissue
 Epithelial: linings, secretes
 Tight junctions: no leaking, small intestine
 Desmosomes: anchor: skin
 Simple to stratified
Organs
 No organs: sponges and cnidarians
 Have groups of different tissue types together for more
complex function.
Bioenergetics
 Flow of energy through animal
 Metabolic rate: amount of Energy per unit time
 Measure by heat lost
 Or oxygen consumed
Bioenergetic strategies
 Endothermic: maintain body temperature:
 Birds
 Mammals
 Exothermic: warmed by external source
 Some very stable If in a stable environment
 Invertebrates, fish
 Differ in source of warmth
Metabolic rate
 Amount Energy needed per gram of body weight
inversely related to body size
 Mouse has high metabolic rate
 Elephant has low metabolic rate. BUT, requires more
energy overall
Metabolic rate
 Smaller animals have higher metabolism: greater
surface to volume ratio: harder to maintain body
temperature.
BMR
 Basal metabolic rate: at rest
 Endotherm: 1,600 – 2,000Kcal/day
 Maximum rate: can not sustain for long
 Use: ATP that’s already present
 Then make some anaerobically by glycolysis
 Start to break down glycogen in liver and muscle cells
Homeostasis
 Maintain stable internal environment
 Receptor – control center- effector
 Conformers: may let one variable change with
environment.
Feedback loops
 Positive feedback: childbirth
 Negative feedback: 1 product of reaction goes back and
shuts down earlier step in reaction
Homeostasis: thermoregulation
 Body temperature monitored in hypothalamus
 receptor
 Information integrated in CNS
 Integration center
 Effector organs:
 If cold: skeletal muscle: shiver
 Erector pili: hair stands up
 Smooth muscle: close capillary beds in periphery
 If hot: sweat gland
Adaptations for thermoregulation
 1. insulation: feathers, hair, fat
 2. circulatory: vasodilate, vasoconstrict, concurrent
heat exchange (birds, marine mammals)
 3. cooling by evaporation
 4. behavior
 5. hormones
acclimatization
 Adjust to new environment over a few days
 Grow thicker fur
 Change metabolic rate
 Ectotherms: change at cellular level: make different
enzymes
 Change proportions of sat/unsat fats
 Heat-shock proteins: protect other proteins from denature
Torpor
 Adaptation: decreased activity & metabolism
 Hibernation
 Estivation: summer torpor