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Vertebrate Zoology
SCBI 305
Circulatory and Digestive Systems
Circulatory System• หน้าที่
– ลําเลียง อาหาร O2, CO2, ฮอร์โมน เม็ดเลือด ไปสู่เซลล์ต่างๆใน
ร่างกาย
– รักษาสภาพอุณหภูมิร่างกาย pH
• Closed system
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.).
McGraw-Hill, Inc., New York.
Blood passes once through heart Blood passes through heart twice
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.).
McGraw-Hill, Inc., New York.
Oxygenated blood
Why are fish hearts small?
ที่มา: Helfman et al. 1997. The Diversity
of Fishes. Blackwell Science.
2
ที่มา: Kardong, KV. 2009. Vertebrates:
Comparative Anatomy, Function,
Evolution (5th ed.). McGraw-Hill, Inc.,
New York.
Bidirectional circulation
Vessels of the circulatory system• Vein
– Blood into heart
• Major veins
– Common cardinal (sinus)
in primitive vertebrates
– Portal system (hepatic
portal veins, renal portal
veins)
– Post-, pre- cava (vena
cava)
• Aorta
– Blood out of heart
• Dorsal, ventral aortae
• Arteries
• Aortic arches
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
Phylogenetic modification
• Correlated with functional changes
Water
Gill respiration
Land
Lung respiration
Pulmonary circulation
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Aortic arches
• Primitive pattern of aortic arches: debatable
• 6 = # taken as the basic embryonic pattern
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
• Fishes
Gills
Ventral aorta
Aortic arches
Capillaries
Gills
Capillaries Aortic arches Dorsal aorta Body
Afferent artery
Efferent artery
1st arch absent
in adult of
most fishes
• Sharks, chondricthyans + primitive ray finned fishes
Modified into small
spiracle (sensory organ)
Lobe finned fish (Sarcopterygii)
Fishes with supplementary air-breathing organ
Lung highly vascularized
Little mixing between oxygenated & deoxygenated blood
(undivided heart)
4
• Amphibians
Larva: arch I, II absent
III, IV, V external gills
VI lung
adult salamander: lost of
external gills
Adult frog: arch III, IV, VI persist
• Reptiles
• Modification of arch IV—systemic arches (double arches)
unite behind the heart to form common dorsal aorta
• Subdivision of ventral aorta
• Arch IV (pulmonary arch) branching out to lung
• Birds
Pre-dominate systemic
arch (left systemic arch not
fully developed)
Wing vessels (subclavians)
Present in turtles & birds
serving as major anterior
vessels in many birds
• Mammals
Only 3 arches (III, IV, VI) present in adult mammals
Carotid arterySystemic arch (left predominates)
Pulmonary arch
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Double systemic arches in
amphibians & reptiles
Single systemic arch (right)
in birds (left) in mammals
Most similar to basic pattern
Aortic arches
Systemic arches
Pulmonary arch
Arterial circuits
Venous vessels • 2 systems in double circulation (Not in fishes)
– Pulmonary systems lung (found in fishes with
lungs, air-breathing vertebrates)
– Systemic systems hepatic portal veins, renal
portal veins, other veins (few differences among
vertebrates, tending to retain basic characters)
• Abdominal veins present in fishes, merged/
absent in tetrapods
Hearts • Original form contractile vessel
– In amphioxus
• Fishes: 4 chamber heart
– Atrium
– Ventricle
– Conus arteriosus found in many fishes, absent in adult
tetrapod
– Bulbus arteriosus (lacking cardiac muscle & conal valves)
found in most teleosts
• Primitive heart (hagfish)
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
6
• Lamprey—4 chamber heart
ที่มา: Kardong, KV. 2009. Vertebrates:
Comparative Anatomy, Function, Evolution (5th
ed.). McGraw-Hill, Inc., New York.
Collect deoxygenated blood containing
pacemaker
Thick wall
Chondrichthyes:
4 chambers
Sinus venosus
Atrium
Ventricle
Conus arteriosus
Gills
Body
Ventral aorta
ที่มา: Helfman et al. 1997. The Diversity
of Fishes. Blackwell Science.
Sinus venosus
Atrium
Ventricle
Bulbus arteriosus
Gills
Body
Ventral aorta
Conus arteriosus—muscular
extension of ventricle
Teleosts:
2 chambers
ที่มา: Helfman et al. 1997. The Diversity
of Fishes. Blackwell Science.
Small—not chamber-like
Small—not chamber-like
Formation of spiral valve in
the conus arteriosus for
regulating blood flow into
left/ right pulmonary arches
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
7
• Frog heart: 3 chambers
– 2 atria, 1 ventricle
Body
Right atrium
Lungs/ skin
Ventricle
Left atrium
Ventricle
Body
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
Close similarity
between lungfish &
amphibians
• Mixed blood in amphibian heart
• Why do their hearts evolve in this direction?
• Amniote heart: 4 major chambers
– 2 atria
– 2 ventricles
• Reptiles (lizards)
– 5 chambered heart (2 atria, 3 compartments of ventricle)
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
Reduced sinus venosus but same functions Completely divided atrium
Ventricle with 3 compartments
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• Reptile (alligator)
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy,
Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
Completely divided ventricle • Cardiac shunt permitting heart to produce
different pressures within systemic & pulmonary
circuits
• Useful
• Bird
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy,
Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
4 chambered heart
Reduced sinus venosus
Conus arteriosus
pulmonary & aortic trunks
• Mammal
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy,
Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
4 chambered heart
Reduced sinus venosus
( Purkinje fiber =
pacemaker) in wall of
right atrium
Conus arteriosus
pulmonary & aortic
trunks
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• Birds & mammals 4 chambered heart BUT
independent evolution
– Seen in embryonic development
Pulmonary circuit Systemic circuit
• Adaptation to environment ≠ improvement of
design
• Incompletely divided heart ≠ imperfect
– Perfectly matching with environment
• Evolution ≠ progressive improvement
– Alternative way of adaptation to demands of
different lifestyles
Heat transfer• Another function of the circulatory system
• Reptiles basking in the sun absorb heat in their
peripheral blood vessels to warm tissues
• Body heat dissipates to surface of body via capillaries
• Endothermic vs. ectothermic
• Homeothermic vs. poikilothermic Animals that show a change in
body temperatureAnimals that maintain constant
body temperature
• Birds & mammals body temperature
regulations using own metabolism
• Other vertebrates body temperature
depending on environments
– Adaptation behaviors (movements)
• Effects of climate change
• Tolerant ranges, limitations geographic
distribution
• Adaptations to climate change?
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ที่มา: Araujo et al. 2013. Ecology Letters 16: 1206-1219.
Lower end Upper end
Limiting factor for
distribution in cold
environments
Temperature
Cold temperature Hot temperature135 species26 species
Limiting factor for
distribution in warm
environments
Natural selection physiological responses to
lower temperature
• Phylogenetic similarity
– Similar responses to temperatures in closely related
species
• Higher temperature narrower cold temperature
tolerance, NOT increasing hot temperature
tolerance
Species cannot survive
กิน
• Eat = put food in mouth, swallow & chew it
• Consume =
• Ingest = take food into body usually by swallowing
• Digest = be changed after eating into a form that the body can use
• Absorb = take in a substance from the surface
• Egest = discharge undigested food as forces
– ≠excretion
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โครงสร้างระบบทางเดินอาหาร
• Buccal cavity: palate, teeth, tongue, oral glands
• Pharynx
• Esophagus
• Stomach
• Intestines: small, large
• Others
Buccal cavity
• Palate = roof of the buccal cavity
– Fusion of ventral skull bones
• Teeth = derivations of dermal armor
– Toothless vertebrates agnathans, sturgeons, some
toads, turtles, birds, baleen whales
– Toothed vertebrates fishes (highly variables), most
amphibians, some reptiles, some birds, mammals
• Teeth in fishes
– Buccal cavity, pharynx
• Tetrapods
– Palate, vomer, palatine, pterygoid bones
• Crocodiles, birds, mammals
– Jaws
• Reduction in numbers and distribution (evolution)
• Succession of teeth
• Tooth replacement in waves (back to front, every other
tooth)
• Mammals 2 sets of teeth
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• Shape of teeth similar in vertebrates except
mammals
• Mammalian teeth incisors, canines, premolars,
molars (heterodont dentition)
• Tongue
• Primary tongue (crescent-shaped elevation in the floor of the buccal cavity caused by the underlying hyoid skeleton)
– Found in most fishes, primitive amphibians
• Primary tongue + glandular field
– Found in most amphibians
• Primary tongue + glandular field + lateral lingual swelling
– Found in reptiles & mammals
• Tongue mobility
– Immobilized turtles, crocs, some birds, whales
– Highly mobile snakes, insectivorous lizards & amphibians
& birds
– Attached to floor of buccal cavity but some mobility
mammals
• Functions: Capturing, gathering food (woodpeckers), Taste,
Swallowing, Grooming, Thermoregulation (dogs), Human
speech
• Oral gland
• Saliva
– Not found in fishes
• Venom (lizards, snakes, mammals)
• Anticoagulant (vampire bats)
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Pharynx • Fish respiratory organ
• Tetrapods foregut
Esophagus
• Muscular tube connecting pharynx and stomach
• Crop (birds)
Stomach • Muscular chamber
• Storage & macerating & secreting digestive enzymes
• Weakly developed in cyclostomes
Diversity of digestive tracts in fishes
Straight tube
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
14
• Differentiated from the esophagus in amphibians,
reptiles
• Glandular stomach + muscular stomach (gizzard) in
birds
• Well-developed in mammals
– Multi-chambered stomach
Intestine
• Variation in fishes
Spiral value—modification
of intestine in
chondrichthyans,
sturgeons, lungfishes,
bichirs, coelacanths,
bowfin, gars—increases
absorptive surface areas ที่มา: Helfman et al. 1997. The Diversity of
Fishes. Blackwell Science.
• Amphibians coiled small intestine, short & straight
large intestine
• Reptiles & birds coiled small intestine, short large
intestine emptying to the cloaca
• Mammals coiled, differentiated, long small intestine,
long large intestine
Others • Liver
• Gall bladder
– Cyclostomes, most birds, some mammals have no gall
bladder
• Pancreas
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• Ceca
– Pyloric & duodenal ceca common in teleosts (for digestion
& absorption)
– Herbivorous Tetrapods (cellulose digestion)
ที่มา: Kardong, KV. 2009. Vertebrates: Comparative Anatomy, Function, Evolution (5th ed.). McGraw-Hill, Inc., New York.
• Cloaca
– End of digestive tract (collection of intestine, urinary,
genital ducts) open to outside
– Opening to outside through a cloacal opening/ vent
– Latin: cloaca = sewer
– Found in all vertebrates during embryonic development
– Shallow or none in lampreys, ray-finned fishes, mammals
(except monotremes)
– Anus (end of digestive tract if no cloaca present)
• Well-developed in sharks & lungfishes
• Remain in amphibians, reptiles, birds, monotremes
• Lost in chimaera, ray-finned fishes, coelacanth,
eutherian mammals
– Anus
Cloaca
Remain
well-developed, subdivided,
incorporated into other structures
Lost
Diet change
• Seasonal variation
– Opportunistic feeders
– Generalists
– Specialists
• Ontogenetic niche shift
– Evolutionary adapatation
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Ontogenetic niche shift• Irreversible, genetically determined
• Morphological changes, age
– Habitat change?
• Driving forces (Claessen & Dieckmann 2002—Evolutionary
Ecology Research vol. 4: 189-217)
– Predator avoidance
– Niche variation