physiology
TRANSCRIPT
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 1/40
Physiology and Functional
MorphologySupplement Text with:
1) a closer look at Cardiovascular system
“respiratory potential dictates virtually all life historycharacteristics known to partition organisms into theirrespective ecological and evolutionary niches”(O’Connor and Claessens 2009)
reproductive biology, activity patterns, locomotion, body
size
2) Consideration of adaptations to withstand cold andheat
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 2/40
homeotherms
poikilotherms
Ta ( C)
10 20 30 40
10
20
30
40
Tb (C)
Homeotherms and
Poikilotherms
(body temp)
Environmental Temp
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 3/40
Homeotherms
• “warm-blooded” vertebrates- birds
mammals
• !aintain "onstant Tb
• #ndothermi" (metabolism is so$r"e
o% bod& heat)
• 'ormal Tb rane is 3-42 derees C
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 4/40
*dvantaes o% Homeotherm&
• Can live in a variet& o% habitats
• Can res+ond ra+idl& to
environmental stim$li
• (,maller animals rea"t more ra+idl&
sin"e their metaboli" rate is hiher)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 5/40
To Be Endothermic Requires Rapid
and Efficient Delivery of Oxygen to
Fuel Metabolism
• In birds and mammals cardiovascular andrespiratory systems have evolved to meet
need for enhanced exchange, transport and
delivery of respiratory gasses (oxygen and
carbon dioxide)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 6/40
Especially at High Elevation
(Scott 2011)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 7/40
Respiration
• The avian lung has the greatest known
relative gas exchange surface area and
thinnest barrier to oxygen diffusion, and incombination with anatomical
specializations is the most efficient lung of
all air-breathing vertebrates at oxygenextraction (from Quick and Ruben 2009)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 8/40
Separate nutrient and waste Streams
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 9/40
Air Sac System
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 10/40
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 11/40
How Breathing
Works
See Fig. 6-5 in text
Negative pressure draws air through, could
collapse
Positive pressure pushes air through, no collapse
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 12/40
Cross Current Exchange
(Scott 2011)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 13/40
Birds Versus Mammals
(Scott 2011)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 14/40
Bellows Move Air• Lungs don’t move
• No diaphragm
• Air sacs fill bodycavity
• Ribs as a bellows
• Unique thighsupports abdominalair sacs
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 15/40
Sternum moves down,
Ribs move forward during
Inspiration
(Claessens 2009)
Muscles to uncinate processes may enable breathing when sternum
cannot be depressed
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 16/40
How to Keep Abdominal air sac
from collapsing during inhalation?
• Modern birds have wide hips– Great pelvic cross sectional area– Egg passage AND
accommodate large air sacs• Synsacrum and integratedthigh with body wall providebony and muscular support tosuspend air sac and keep itfrom collapsing duringnegative pressure ofinhalation
Thigh mass closer to body center (angled up) supports air
sac and doesn’t move much during walking
knee
ankle
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 17/40
When did These Specializations
Evolve?
(Sereno et al. 2008)(Sereno et al. 2008)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 18/40
When did These Specializations Evolve?
(Sereno et al. 2008)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 19/40
Staying Warm
• Feathers:increase # 15-52%, (depending on species)– Down and semiplumes provides insulation
• Feathers-”fluffing”-traps air– Effects of oil blob= creates a thermal window
• Lay on Fat• Large Body size (SA to V)•
Vasoconstrict, shiver• Migrate (latitude, altitude)• Burrow, group up
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 20/40
Tree Creepers (European)
The huddled masses.
*d t ti % C ld C diti
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 21/40
*da+tations %or Cold Conditions
avoidin H&+othermia
•Hibernation (also has +h&sioloi"al behavioral as+e"ts to it) – *llow Tb to a++roa"h Ta
– .ew birds hibernate
– Partial hibernators h$mminbirds
(at niht)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 22/40
*da+tations %or Cold Conditions
avoidin H&+othermia•
,+e"ial Case 1 the Poorwill
– /is"overed b& #C aeer on /e" 2 14 in
the Ch$"kwalla !ts o% so$thern Cali%ornia
– /e+ression in a ro"k wall 2 %eet %rom ro$nd
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 23/40
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 24/40
Jaeger, 1949
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 25/40
From Jaeger, E.C. 1949: Condor 51:105-109
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 26/40
*da+tations %or Cold Conditions
avoidin H&+othermia• ,+e"ial "ase 2 hih
latit$de +en$ins
• 5ives in botha6$ati" andterrestrial worlds
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 27/40
*da+tations %or Cold Conditions
avoidin H&+othermia
• ,+e"ial "ase 2 +en$ins
• 7n water
•Chroni" +roblem o% heat loss•lare tem+erat$re radient-o%%set b&
thi"k la&er %eathers and thi"k bl$bber
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 28/40
*da+tations %or Cold Conditions
avoidin H&+othermia
• 8n land breedin season birds ha$l o$t on
islands o%% *ntar"ti"a
• territorial de%ense9 heat +rod$"tion
• in water heat lost easil& not in air on land•breedin a"tivities %all o%% on"e T* rea"hes
• 4 derees .
•.li++ers (modi%ied wins)- a thermal window
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 29/40
*da+tations %or Cold Conditions
avoidin H&+othermia:h& don;t the %eet o% d$"ks eese $lls et"
%ree<e to i"e=
*nswer a "o$nter-"$rrent me"hanism
(arteries and veins ne>t to ea"h other)
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 30/40
Countercurrent Mechanism
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 31/40
Avoiding Hyperthermia
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 32/40
*da+tations %or Hot Conditions
avoidin H&+erthermia?irds
•
Pre-ada+ted %or hot "limates-hih T?(4- . hiher than mammals)
• !ost birds are neither no"t$rnal nor%ossorial so m$st meet the environment
head-on
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 33/40
*da+tations %or Hot Conditions
avoidin H&+erthermia,tr$"t$ral ada+tations
!i"roevol$tion o% bod& si<e
.eathers- same idea as h&+othermia
e>"e+t that &o$ want to red$"e air s+a"e
C858@A5iht vs /ark B :ind vs Calm
Thermal windows ?are +la"es on skin-
birdsA$lar +o$"h %eet les %a"e
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 34/40
*da+tations %or Hot Conditions
avoidin H&+erthermia
Ph&sioloi"al ada+tations
• Cardiovas"$lar "hanes-dilate bloodvessels to send more blood to skin s$r%a"e
also in"reased "ardia" o$t+$t
• #va+orative "oolinA+rimar& wa&
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 35/40
*da+tations %or Hot Conditions
avoidin H&+erthermiaPh&sioloi"al ada+tations
?irds
•no sweat lands
•eva+orate water over l$ns air sa"s
and $lar +o$"h (some)
•
a""om+lished b& +antin $lar%l$tterin
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 36/40
Evaporative CoolingProlonged exposure to high ambient temperatures
Hyperthermia
Hyperventilation
Evaporative cooling
Rapid exchange of air
through air sacs
Body temperature lowers
vasodilation
Increased cardiac output
More blood sent to:
Skin surfaceFeet, wings, gular area
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 37/40
*da+tations %or Hot Conditions
avoidin H&+erthermia
• 7n"rease water
intake
• ,eek "ool +la"es-shadows
veetation to
red$"e heat ain
Ph&sioloi"al ada+tations
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 38/40
*da+tations %or Hot Conditions
avoidin H&+erthermia
?ehavioral ada+tations
*"tivit& +atterns
• be"ome less a"tive
• be "re+$s"$lar
• be no"t$rnal
• be a"tive near water
.ossorial habits
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 39/40
Sooty tern
7/21/2019 Physiology
http://slidepdf.com/reader/full/physiology-56d8117f26a76 40/40
Additional References
• Claessens, L. P. A. M. 2009. The skeletal kinematics of lungventilation in three basal bird taxa (emu, tinamou, and guinea fowl).J. Experimental Zoology 311A:586-599.
• Quick, D. E. and J. A. Ruben. 2009. Cardio-ppulmonary anatomy in
theropod dinosaurs: implications from extant archosaurs. J.Morphology 270:1232-1246.• O’Connor, P. M. and L. P. A. M. Claessens. 2009. Respiratory
evolution in sauropsids: progress and new approaches. J.Experimental Zoology 311A:549-550.
• Sereno, P. C. et al. 2008. Evidence for avian intrathoracic air sacs in
a new predatory dinosaur from Argentina. PLOS one. 3(9). E3303.• Scott, G. R. 2011. Elevated performance: the unique physiology of
birds that fly at high altitudes. J. Exp. Biol. 214:2455-2462