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Body size is limited by
body mass, limits in mobility
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Exchange of nutrients and amount of material needed
- Exchange of nutriens waste and gasses are proportional to membrane surface area
- amount of stuff needed is proportional to cell volume
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Simpler body lans
enable direct exchange with environment
-
flat body maximizes
exposure to environment
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More cells
smaller ratio of outer surface area to volume
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internal body fuids
link the exchange between surface and cells
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Interstitial fluid
fluid between cells
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circulatory fluid
- only complex body plans
- exchanges with interstitial fluid
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Epithelial types
- stratified squamous epith = regensrapidly
- Cuboidal Epi > secretion> kidneys> glands
- Simple columnar ep>intestinal secretian
- Simple squamous> exchange difusion, blood vessels, air sacks
- Pseudostratified columnar epi>single layer>mucous membrane of resp tract
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Connective tissue
- Fibroblasts and macrphages
- 3 types of fibers
- collagen (joins tissues) Reticular (srengt and flexibility) Elastic (elasticity)
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Loose connective tissue
holds organs in place
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Fibrous CT
tendons and ligaments
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blood is also
connective tissue
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Cartilage
strong but flexible support material
-
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glial cells
noursih and replenish neurons
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Regulator feedback
internal mechanism control internal change to face external fluctuation
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Conformer feedback
internal conditions change in accordance with external
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Homeostasis mechanisms
- a) set point
- b) sensor
- c) stimulus
- d) response
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Acclimatization
Gradual adjustement to external changes
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4 processes for heat regulation
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Integumentary system
body covering
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Countercurrent exchange
transfer of heat between fluids that flow in opposite directions
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thermogenesis
- varying heat production to match changes in heat
- shivering or moving
- nonshivering> increases metabolism to produce heat instead of atp
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Ectodermal heat regulation at cellular level
lipid saturation, enzymes
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bioenergetics
flow and transformation of energy related to body size, activity and environ
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Metabolic rate
- energy used in a unit of time
- joules, calories or kCals
- bmr>basic endotherms rate at rest
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BMR in ectoderms
depends on temperature, standard metaboic rate for that temperature
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Influences on metabolic rate
- 1) M = m^.75
- 2) energy per gram is inversely related to body size
- 3) smaller animals have higher metabolic rate per gram, higher breathing rate, higher heart rate and need more food per uni of body mass
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BMR
- maintenance energy
- BMR>Activity>thermoreg>reproduc>growth
- Ectotherms have no thermore cost
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Torpor
- physiological state o decreased activity
- hibernation - long torpor, circadean rhytm seases
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