ADVANCED LEC

05ORNITHOLOGYUniversity of Rio Grande

Donald P. Althoff, Ph.D.

Anatomy & Physiology

Part IIReference Chapters 1 & 6

• Birds and mammals regulate their body temperatures “just” below temperatures that destroy body proteins. Curved line represents the ________________________

_________ Temperature of Birds

BIRDS

Higher Body Temperatures

• In frigid Arctic regions and hottest deserts, most birds have 40oC internal body temp. Most birds ________ (~104-110oF)

• High body temp enhances intrinsic reflexes processing powers—enable active-fast moving capabilities.

• Higher temps—higher rate of physiological processesex. transmission speed _____________

increase 1.8 times with every 10oC increase in temp ex. speed and strength of _______________ _______________ triples with 10oC increase in temp

Respiratory Systems

NOTABLE CHARACTERISTICS

• Lungs small and compact (compared to mammals)• Lungs are spongy structures “molded” along the ribs.• Dense tissues of avian lungs weigh as much as lungs

of mammals of equal body weight but only occupy about have the volume

• Healthy lungs are ___________ in color• Healthy lungs are _______________• AVIAN LUNGS are unique in that air flows in only

_____________ (vs. in and out for other vertebratesGary Ritcheson EKU

Respiratory System…con’t

• Most birds inhale air through nostrils / _______ at the base of the bill

• For __________, a flap—or __________—covers and protects the nostrils from water while diving.

• For ________________, the operculum is present to keep pollen out.

• Nasal chamber “folds” –________– (see Fig. 6-3 Gill) that increase the surface area for air to flow over: a) _______ the air b) _______ the air

trachea

Gill Fig 6-2 ↑

Diagram of the lungs and air sacs of the bird. Ventral view on left, dorsal view on the right. Inspiration part of system shown in “black”; expiration part of system shown in “stipple” pattern.Source: Pettengill (1985) Fig. 22, page 74.

Doral viewVentral view

cervical sac

mesobranchimesobranchi

recurrent bronchi

posterior thoracic air sac

abdomenal air sac

dorsobronchiparabronchi

cervical sac

opening of mesobranchi

into the air sacs

anterior thoracic air sac

diverticulum of the interclavicular sac to the

sternum, coracoid, clavicle, and humerus

Interclavicle air sac

tertiary bronchi

(parabronchi)

connections to air sac

secondary bronchi

primary bronchi

Internal structure of bird lungInterconnecting Bronchial Tubules—

Gill Fig 6-4a

Gill Fig 6-4b

• Tertiary bronchi (i.e., parabronchi) and fine air capillaries constitute most of lung tissue--

Closer look—lung tissue

About _____

of these

tertiary

bronchi

____-directional movement of a single Inhaled volume of air—shown in white

Cycle 1

Cycle 2

inspiration

expiration

inspiration

expiration

1

2

3

4

_______________respiratory cycles (inspiration, expiration, inspiration and expiration) are required to move the gas through its complete path.

Gill Fig 6-5

UNI-directional …con’t

Cycle 1

Cycle 2

This “design” ____________ contact of fresh air with respiratory surfaces of the lungs.And…most importantly allows a bird to replace nearly _________ in its lungs with each breath

This “design” makes for a ________________ of gas exchange than do mammals

Gill Fig 6-5

Respiratory System…AIR SACS• Although inconspicuous, the air-sac system is integral

part of the avian respiratory system.• Number of air sacs varies from 6 in weavers, to 7 in

loons and turkeys, to at least 12 in shorebirds and storks. Most birds _______.

• The paired cervical sacs located in the neck are perhaps the most visible: they inflate as large red sacs on the necks of displaying frigatebird and strutting sage grouse

Respiratory System…AIR SACS…con’t

• ____________ (only 1-2 cell layers thick)• Extend throughout body cavity AND into wing and

leg bones• Connect directly to primary and secondary bronchi• Help continuous unidirectional flow of air through

lungs…facilitating ____ transport• Help remove potentially lethal _________ generated

during flight• Air pressure from the single interclavicular sacs is

essential for _________ production (more about that when vocalizations are covered).

Respiratory System…con’t• During flight:

expansion and contractions of the ________ complement the movements of the

sternum… this helps pump air through the respiratory system.

• High speed video of common starlings shows:furcula bends ________ during wings’

downstroke and then ___________ on upstroke….the expansion is almost ______ more than in

resting width…and does so with each wing beat! • Rate of breathing varies by species—including by size

of bird & by activity. Resting 2-g hummingbird -143 bpm; resting 10-kg turkey breathe – 7 bpm. Increase rate by ___________________!

Digestive SystemsNOTABLE CHARACTERISTICS

• _____________• Bill and mouth primary function is _____________ (vs.

some “mastication”)• Bill/mouth for some capable of cracking and shucking

seeds or tearing prey into bite-size pieces• Crop—for some—is temp food storage• __________: size and degree of presence varies by

species…and that is associated largely with diet. A substitute for teeth.

• GI-tract size and structure can vary seasonally• Have ______ taste buds and _______ saliva• _________ digestion begins in the ________________

Digestive SystemsNOTABLE CHARACTERISTICS… ____________

• Very muscular structure• Lined with lubricating __________ glands• For large prey swallowed whole, it _________ greatly

(think pelicans!)• In pigeons, it produces what is know as “_________”

for young• In pigeons and other species, it can be ________ for

display and sound resonance• The “crop” is a __________ of the esophagus

Digestive System

• Oral cavity• Pharynx• Esophagus• Crop (*)• Proventriculus• Gizzard• Small intestine• Large intestine• Cecum• Cloaca

• Liver• Pancreas

Don’t forget the Hoatzin…modified CROP allows“ruminant-like” digestion

MAIN TRACT AUXILLARY

Earthworm

mouthpharynx

esophagus

CROP GIZZARD

small intestine

anus

esophagus

Pettingill Fig 34

crop

proventriculus

gizzard

small intestine

large intestinecloaca

vent

cecum

pancreas

duodenum

liver

Fig. 17-22 p460, PJH

esophaguscrop

proventriculus

gizzardpylorus

small crop

Small

Gizzard

Large

andmuscular

• Opisthocomus comes from the Greek meaning "wearing long hair behind"

• Nicknames include: reptile-bird (because of their crocodilian

odor & harsh monotonous call)flying cow (because of it's clumsiness in the

air and unusual diet)• Has a diet of leaves…which means it has to have a way

to breakdown cellulose “______________” stomach

Hoatzin

Hoatzin (Opisthocomus hoazin)

• Skeleton modified to accommodate large crop – fermentation vat housing bacteria that help it breakdown cellulose to obtain “the good stuff” (proteins/sugars) in the plant material (not unlike what ungulates do)

• ______ bird species that has the “foregut fermentation” approach to handling plant material containing cellulose

• Rests on a sternal callous while lengthy digestion takes place. The callosity is an elliptical, horny patch of skin lying over the rear tip of the sternum

• Feeds chicks ________________ mush of leaves

Hoatzin…con’t

• Length of bird’s intestinal tract averages 8.3 times its body length. In the common swift, it is only 3x. For the common ostrich it is 20x.

A) diet—fruit, meat, and insects: __________B) diet—seeds, plants, & fish: _________

• Near end of digestive tract: small side sacs called _____ (________ is singular). Attach to large intestine.

A) aid digestion—especially fibrous plant foodsB) produces antibodies C) aid absorption of H2OD) aid in metabolism of uric acid into amino acids

Digestive System –con’t

• Overall, digestive system extracts nutrients and energy with high efficiency

a) fruits and berries “pass through” in ______b) other foods (non-fibrous) < _______

• Like mammals, some nutrients absorbed by active transport. Most birds absorb glucose (i.e., simple sugars) and amino acids by active transport. Other nutrients passively with other fluids. “______________” requires little energy…and concentration dependent.

• Toxins in fruits and seeds also may be absorbed indiscriminately

Digestive System –con’t

• Parrots eat seeds and bitter green fruits—many full of toxins that are distasteful and lethal to other animals

• Some parrots eat dirt…long thought to simply provide grit for the gizzard. ____________ in ‘dirt’ has minerals that are _______ to toxins. Kaopectate, which consists partly of clay, soothes human upset stomachs in this way. - charged sites of clay minerals “bonds” to + charged toxin molecules

• Some variable stomach designs among seed-eaters.Notably the phainopela—in the gizzard, the exocarps from mistletoe berries “off” to the side, then pass in “packet” until excreted (see next

slide)

Digestive System –con’t

Gill Fig 6-21

Prim

itive

flow

erpe

cker

Blac

k-sid

ed

flow

erpe

cker

Viol

aeou

s eu

phon

ia

phainopelpa

• Raptors: 66-88% energy of ingested meat and fish• Herbivores: 60-70% energy in young plants• Herbivores: 30-40% energy in mature foliage• Spruce grouse: 30% in spruce leaves…a very hard-to-

digest foliage

• Fruits provide “predigested” nutrients in the form of free amino acids (vs. proteins) and in the form of simple sugars (vs. complex carbs). Such easily digest and absorption allow the 20 minutes or less pass through time

Digestive System –assimilation efficiencies

• ______________________________ favored by cedar waxwings. Because of “abundant” glucose and fast passage through the GI tract, lots of glucose is in the semi-digested fruit pulp just before evacuation. Cedar waxwings may be unique in that they absorb this “extra” glucose via active transport in its rectum.

--also, this “junkfood” diet preference requires protein-rich cottonwood catkins to supplement their diet

• _______________________________ favored by North American thrushes

Digestive System –Fruits & Fruit-eating birds

• Many passerines ______________________—a complex sugar because they lack sucrose, the enzyme facilitating breakdown of sucrose to glucose and fructose. Ingestion of high concentrations by such species can cause sickness and diarrhea—resulting in ____________…thus they avoid it. Ex. Common starling

• In contrast, hummingbirds feed on sucrose-rich nectar. They assimilate ________ of the energy in nectar. Do this rapidly by means of unusually high densities of sites that actively bind sugar and transport it across cell membranes.

Digestive System –Sucrose…no Sucrose

Changes in Starling GI tract

• Response to ___________ availability of certain food types

• Higher plant content in diet (need more time to digest to extract nutrients) results in longer intestinal tract (~ _____ increase in length)

• Besides anatomical changes, digestive enzyme composition changes, too, to different food types they consume:

a) simple sugars in fruit vs.

b) fat and protein in animal-based food

Fig. 17-23 p461, PJH

Starling (Sternus vulgaris)

Plant material in diet

length of intestine

Feeding & Digestion

• Many specializations—especially with respect to beak & tongue designs

• Beak designs include:insect catchers insect netfruit plucker generalized billflesh tearer dip netfish grasper fish spearmud sifter water strainerseed cracker pine seed extractor

Fig. 17-19 p457, PJH

American woodcock

• For _______ species, ability to raise the tip of the bill without opening the mouth provides opportunity to exploit food sources in the sand (some shorebirds) and/or soil (woodcock)

• Woodcock shown here has beak that is 3+ inches long—probes for earthworms

Fig. 17-20 p458, PJH

Woodpecker—probing tongue

Anteater---probingtongue with different origin for tongueattachment (on sternum)but same result

Mammal-version

food-straining (NORTHERN SHOVELER DUCK)

Fringed, tubular nectar feeder fruit-eater (Diard’s trogon)

fish-eater (sooty shearwater)

(bananaquit)

general feeder (robin) probing-spearing (woodpecker)

NECTAR FEEDERS

magnificent hummingbird

green violet-ear hummingbird

fiery-throated hummingbird

volcano hummingbird

• Note the _____ of the bill

• Note the __________ of the bill

Circulatory SystemNOTABLE CHARACTERISTICS

• Proportionately large• 4-chambered—left and right separation• Overall design: similar to mammals (i.e.,

humans)

Circulatory System

• Most efficient design of all among vertebrates (along with mammals)

Pulmonary circulation

Systemic circulation

Circulatory System…output

• Heart, liver, kidneys and intestines: 8-10%• Brain and eyes: 3-4%• During flight or swimming, cardiac output

allocations to flight and leg muscles, respectively, _________ dramatically

• Also: _________ empty more completely than do those of mammals on each contraction. More ___________ in ventricles than comparable size mammals

Pettingill Fig 35

Urogential SystemNOTABLE CHARACTERISTICS

• Because of “exit” anatomy, the urinary system and the reproductive system considered together—hence the “urogenital” designation

• “Exit” point is the _______a) meeting point for urinary system, digestive system, and reproductive systemb) Latin for “sewer”c) same in reptiles, amphibians

• _______ functional ovary

Pettingill Fig 36

adrenal gland

kidney

testis

ovary

oviduct

vas defrensureter

large intestinecloaca

vent

FEMALEMALE

Excretory System

• Excretion of water and _______________ takes place in the kidneys and the intestines—and in some species by the action of salt-secreting glands.

• Relative to most mammal kidneys, bird kidneys are relatively flat

• Different from both mammals and reptiles: A) Urine produced by kidneys mixes with fecalcomponents in the _____________ B) Also, at this point in lower intestine H20 can be resorbed…as needed

Excretory System…con’t

• Key physiological adaptation: promotion of water economy is the excretion of nitrogenous wastes in the form of __________

• Uric acid are the white crystals that give bird droppings their unusual color.

• Nitrogenous waste a result of body structures that produces nitrogenous products that become toxic if allowed to accumulate. For mammals, they handle this by producing urea in aqueous solution that requires large quantities of water. Uric acid can be excreted as a __________________ in which each molecule of uric acid can contain _______ as much nitrogen as a molecule of urea

Excretory System… Uric Acid…con’t

• This process of excretion results in huge efficiencies with respect to ____________: A) 0.5 to 1.0 ml of water to excrete 370 ml

of nitrogen as uric acidvs.

B) 20 ml of water to excrete same amount of nitrogen as urea

• Concentrations of uric acid in the ______—just before defecation—can be as much as _______ the acid level in the blood stream! In the mammal world, even the best at this—kangaroo rats—have concentrated urea in urine to “only” 20-30 times.

Excretory System… Hummingbirds

• Too much ______ “problem”• Result of ______ composition—lots of water• Anna’s hummingbird documented to, on a daily

basis, consume up to _____ its body mass in nectar• The rate of water moving through and excreted is

among highest known to freshwater amphibians• Kidneys are not different from other birds, just these

species have highest rates of evaporative water among birds AND some of the water is keep in the digestive tract and therefore does not pass through the kidneys

Excretory System… Salt and Oceanic Birds

• Loops of Henle in avian kidney (i.e., nephrons) are short compared to mammals. This poses challenge to birds that drink saltwater.

• Saltwater is about 3% salt. Body fluids are about 1%• This high concentration increases need to excrete

electrolytes. This salt excretion is aided by presence of ______________ (Gill Fig. 6-27, pg 178). A) just above eyes B) rapid unloading bloodsystem system C) special “infoldings” of cellular lining of the nares. Linings contain secretory tubules… that get salt from ________________ of the _________________ D) tubules connect to central canal and drip out

Genitals – Male: Testes

• paired• ellipsoid • asymmetry typical—left usually larger• during breeding season, up to ____ increase in size• vas deferens contain the sex cells/spermatozoa from

the testes• seminal vesicle stores sperm until copulation• no penis or “external” genintalia. But there are

exceptions. For the most part copulation takes place via brief cloacal contact: known as a ___________.

More on mating…later in the course

Genitals – Female

• single ovary• cloaca in female generally smaller but lips of the vent

tend to protrude more conspicuously

• Also, both for males and females—during dissection of fresh specimens, gonad tissue will be _______ vs. adrenals which will be highly colored (orange-yellow usually) and larger.

Summary

• High ___________• Flight and maintenance of high body temperature requires

large amounts of _________• Both circulatory and respiratory systems ___________ to

meet these demands by delivering fuel removal of metabolic wastes

• Adjustments to ____________________ by a) adjusting plumage insulation b) shivering c) evaporative water loss

• Mostly _______ of passage of foods through digestive system

• Excretion via uric acid minimizes water need…________.