Lecture 2 & 3 - Avian Anatomy And Physiology Flashcards

1
Q

Define topography

A

The appearance of the animal - external structures

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2
Q

How many species of birds are in the world?

A

About 8500

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3
Q

Taxonomically, birds are placed in the class _______

A

Aves

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4
Q

What is the primary distinguishing feature of birds?

A

Feathers

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5
Q

How do birds birth their young

A

Lay eggs

Oviparous

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6
Q

What are the only other species that flies besides birds?

A

Bats

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7
Q

The dermis of birds is made of a thin flap of epithelial cells that produce keratin. What structures is this necessary for?

A

Outer sheath of break and claws

Feathers

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8
Q

The dermis is a thicker, fibrous connective tissue layer. What are the two main responsibilities of the dermis?

A

Storage for fat

Movement of muscles via smooth muscles (heat regulation)

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9
Q

True or false:

Birds have sweat glands

A

False

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10
Q

What is the uropygial gland, what does it do?

A

The preen gland

Found on the dorsal surface at the base of the tail feathers

Secretes an oily fatty substance that waterproofs the feathers

Varies in size with species

Lacking in some species (parrots and flightless birds)

Birds put oil on their beak and rub it all over their feathers

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11
Q

What do birds that do not have a preen gland often prefer rather than water baths?

A

Dust baths

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12
Q

Describe the beak of birds, what determines their shape?

A

Derivative of a bird’s skin (keratin formation) it is covered in a horny keratin layer

Varies in hardness, flexibility and shape based on the function and what the bird eats

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13
Q

True or false:

Bird beaks grow continuously

A

True

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14
Q

What does it mean if a birds beak grows continuously?

A

Surfaces and foods to help maintain normal length must be provided

Trim and file the beak if needed

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15
Q

What can a beak overgrowth indicate?

A

Internal problems

Nutrient problems

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16
Q

Describe the claws of birds. How do they differ between species?

A

Horny sheath derived from specialized scales (end of each toe)

Grow continuously

Differ based on perching habits and how the procure food (hunting or not)

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17
Q

“Quick” a bird’s nail

A

Cut too deep and hit the blood vessel within the nail

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18
Q

True of false:

Feathers are living structures on the bird

A

False

They are non-living structures

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19
Q

Describe feathers.

What are their 5 main functions?

A

Outgrowths of skin made of protein

1) Flight
2) Protection
3) Thermoregulation
4) Camouflage
5) Communication between birds

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20
Q

Where do feathers have sensation?

A

At the base in the area of attachment

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21
Q

What are the anatomical parts of a feather?

A

Quill/calamus

Rachis

Bards

Distal and proximal umbilicus

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22
Q

Describe the anatomy of feathers

A

Quill/calamus: hollow tube below the fluffy part of the feather (no barbs)

Rachis: continuation of the quill with barbs attached

Bards: individual hair strands

Vane: a group of barbs held together by hooklets and barbules

Distal and proximal umbilicus: distal - hole at the end of barbs. proximal - hole at the end of quill

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23
Q

Define contour feathers

A

Most visible feathers

Give shape to the bird

Most compact microstructure: quill, rachis, vane (barbs, barbules, hooklets)

Have a tight structure on the fluffy part of the feather - held together. Often contain the colour of the bird.

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24
Q

Describe contour feathers

A

Most visible feathers

Give shape to the bird

Most compact microstructure: quill, rachis, vane (barbs, barbules, hooklets)

Have a tight structure on the fluffy part of the feather - held together. Often contain the colour of the bird.

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25
Q

Describe semi-plume feathers

A

Found under contour feathers (mainly on sides, necks, and back)

Provide insulation, flexibility and buoyancy in water birds

Central rachis with free barbs (no barbules or hooklets) (barbs not held together)

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26
Q

Describe down feathers

A

Soft, fluffy, located next to the skin

Function in insulation

No rachis, only a calamus with free barbs

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27
Q

Describe powder down feathers

A

Specialized type of down feather

Never stop growing

Disintegrate at the tip which creates a waxy powder that spreads on the plumage through preening (clean and waterproof bird)

Highly developed in birds without uropygial gland

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28
Q

Describe a filoplume feather

A

Sensory or decorative in function

Elongated rachis with barbs only at distal portion

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29
Q

Describe bristle feathers

A

Modified contour feathers

Serve as sense of touch

Location depends on species

Long, tapered rachis, few or no barbs at the base of the rachis

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30
Q

True or false:

Feathers originate all over the body

A

False

Feathers overlap and are laid down in tracts with areas of bare skin in between

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31
Q

Describe apteria

A

Where feathers do not grow on birds (bare areas)

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32
Q

Describe molting

A

The process of replacing feathers

Occurs in species specific patterns (allows birds to continue on with life)

Generally a gradual process

Usually occurs symmetrically on the body

Only one or two major flight feathers at a time

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33
Q

When is the major molting time?

A

Fall

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34
Q

What is different about water fowl molting?

A

They lose all their feathers at once following the breeding season

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35
Q

Where do feathers grow from?

A

Papillae in feather tracts of the dermis

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36
Q

What pushes out old feathers?

A

A newly developing feather

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37
Q

What are feathers first covered in?

A

Emerges covered in periderm

Is removed by preening

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38
Q

What is the objective of wing clipping?

A

Clipping feathers so the bird cannot get lift and fly, while still being able to glide down from perches etc.

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39
Q

Describe how bird wings are clipped

A

Trim 5-7 flight feathers under the coverts

Trim outermost feathers OR leave 2 or more primary feathers intact

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40
Q

Why should blood feathers (immature feathers) not be clipped or the feathers on either side of them?

A

These will cause major bleeding when cut

Don’t trim on either side to protect them from breaking

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41
Q

Where do primary flight feathers originate from?

A

The “hand” (metacarpus and digits)

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42
Q

Where do secondary flight feathers originate from?

A

Radius and ulna

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43
Q

Describe the major and minor coverts

A

The feathers that cover the starts of flight feathers

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44
Q

What do external parasites do to feathers?

A

Chew and consume parts of the feather vanes, creating weak points

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45
Q

Damage to feathers can also be due to?

A

Daily wear and tear

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46
Q

Describe a fault bar

A

A stress bar

Weakened area in the feather vane where barbs lack barbules

Feather is stressed during its growth when blood flow is disrupted

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47
Q

What is the most common stressor for birds?

A

Diet

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48
Q

Describe feather picking

A

Common in captive psittacines and imprinted raptors

Can be cause by boredom or disease (parasites, infection, toxins)

Over picking of the feathers

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49
Q

What is the main cause of feather picking in small birds?

A

Medical cause

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50
Q

What is the main cause of feather picking in large birds?

A

Behavioral issues

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51
Q

What cause of feather picking is harder to treat?

A

Behavioral

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52
Q

What are modifications of the musculoskeletal system of birds that allow for flight and walking?

A

Reduction in number of bones

Fusion of some bones to form plates (keel)

Reduction in bone density

Loss of internal bone matrix (hollow, air filled spaces)

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53
Q

Describe the axial vs appendicular skeleton

A

Axial: skull, vertebrae, sternum (framework)

Appendicular: wings, shoulders, legs, pelvis (locomotion)

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54
Q

Describe the skull of a bird

A

The jaw bone extends into the keratinized bill

Large eye sockets bordered by sclerotic ring

Very small portion of skull devoted to olfactory system

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55
Q

True or false:

Birds have a greater number of cervical vertebrae

A

True

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56
Q

Describe the thoracic vertebrae of birds

A

Rigid to provide strong support for ribcage

Have the uncinate process that overlap adjoining ribs

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57
Q

Describe the lumbar and sacral vertebrae of birds.

A

Fused vertebrae form bony plate to support legs (synsacrum)

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58
Q

Describe the coccygeal vertebrae of birds

A

First few mobile to allow movement of tail feathers

Pygostyle: fused bony structure that supports tail feathers

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59
Q

True or false:

Lumbar and thoracic vertebrae do not move

A

True

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60
Q

Describe the sternum of birds

A

Large and concave

Protects the chest

Acts as a place of origin for flight muscles (keel) (pectoral muscles are the flight muscles)

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61
Q

Describe the three complex bones of the shoulder

A

Coracoid: prevents the collapse of the whole structure from the force needed to push wings together

Scapula

Clavicle (wishbone): fused clavicles are called a furcula

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62
Q

Ture or false:

There is more force needed for the down stroke during flight

A

True

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63
Q

Describe the movement of the shoulder

A

Allows several planes of rotation

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64
Q

Wing muscles attach at the

A

Pectoral crest of the humerus

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65
Q

The humerus is longer in birds that?

A

Glid and soar

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66
Q

Describe the movement of the elbow

A

Only allows movement parallel to the wing

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67
Q

What is the patagium (propatagium)

A

The web of skin that extends from shoulder to wrist

Assists in aerodynamics

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68
Q

What are the alula bones

A

First digit that originates from the wrist

Carries the alula feathers (steering) for fine control

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69
Q

Describe the metacarpal bones

A

Fused to form major and minor metacarpals

2 in total

Join with digits 2,3,4

Help support primary flight feathers

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70
Q

Describe the pelvis of birds

A

3 paired bones join where leg attaches to body (ileum, ischium, pubis)

Distal ends of pubis not fused: provide room to facilitate egg laying

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71
Q

Describe the legs of birds

A

Femur is directed forward to the knee

Some tarsal bones are fused with the tibia forming the tibiotarsus

Some tarsal bones are fused with the metatarsals to form the tarsometatarsus

Single bone of the “hock” spans from the ankle to the digits

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72
Q

Describe the feet of birds

A

A metatarsal pad on the bottom of the foot surrounded by 2, 3, or 4 digits

3rd toes is usually the longest

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73
Q

Describe anisodactyl, give some examples of these

A

One toe faces to rear, other three face forward

Galliforms, raptors, song birds

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74
Q

Describe zygodactyl, give an example

A

2nd and 3rd toes face forward

1st and 4th toes face backwards

Parrots

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75
Q

Describe bumble foot

A

Infection of the feet, usually from a staph infection

Causes severe swelling, ulceration and discomfort

Linked to perches that are all the same size, too rough or not rough enough, or long claws

Change the perches and treat with antibiotics and preparation H (topical)

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76
Q

Why is it difficult to treat feet problems in birds

A

Birds are always on their feet, walking in feces especially

Infections spread fast since there is little tissue surrounding and very close to bone

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77
Q

Many muscles of birds are placed

A

Ventrally, near the center of gravity

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78
Q

What are white fibers in muscles

A

Thick
Low blood supply
Little myoglobin
Uses stores of glycogen

Found in flight muscles of short distance fliers

Exhaust quickly

“White meat” in bird breasts

Sprinting, short bursts of flight

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79
Q

What are red fibers in muscle

A
Thin 
Large blood supply 
Fat 
Lots of myoglobin 
Mitochondria 

Found in flight muscles of long distance fibers

Dark meat (legs)

Marathon runners, flying for long distances

80
Q

Describe what muscle fibers birds have depends on

A

Depends on lifestyle of birds (fliers vs walkers)

Some muscles have one or the other or a combination of both

81
Q

Describe the movement of wings in flight and the muscles involved

A

Both muscles found on the chest responsible for raising and depressing the wing

The pectoralis muscle is larger and more superficial, flexion causes the wing span to close (down stroke)

The supracoracoideus is smaller and deeper, flexion causes the humerus to move and the wing span opens (up stroke)

82
Q

What is the muscle of choice for IM injections in birds

A

The pectoralis muscle

83
Q

Describe the muscles of the legs in birds, how are the toes controlled?

A

Primarily located over the femur

Control movement of the toes through long tendons

84
Q

What is the perching reflex

A

Claws close as the leg flexes

Allows bird to remain perched while sleeping (won’t let go or fall off)

85
Q

How can the perching reflex be used when clipping nails?

A

Extend the leg to open the claws

86
Q

Describe the muscles of the head and neck

A

Extent of the jaw muscles vary depending on diet (strength needed to eat specific foods - hard nuts vs seeds)

Neck muscles allow movement in different directions

87
Q

Describe the hatching muscle and the “egg tooth”

A

Aid in the newborn chicks to break through their shell

Hatching muscle is on the back of the neck to give power when breaking shell (atrophy after bird)

Egg tooth is a small cornified structure on the beak to aid in breaking

88
Q

Describe the brain of birds, what differs compared to mammals?

A

Large in proportion to its body

Location of different centers are similar to mammals, but have a large center for vision and hearing, and a small center for taste, touch, and smell

89
Q

Describe the vision of birds

A

Highly developed

Large portion of the skull is made for housing and protecting the eyes (shape of the eye depends on the orbits)

Has limited movements in some species (most have to move their entire head rather than their eyes - owls)

90
Q

Describe the shape of diurnal birds’ eyes

A

Round or relatively flat eyes

91
Q

Describe the shape of nocturnal birds’ eyes

A

Tubular (elongated)

92
Q

What are the 3 main divisions of the anatomy of the eye

A

Fibrous tunic

Uveal tunic

Neural tunic

93
Q

What does the fibrous tunic contain? What are some specialized structures in this area in birds?

A

Sclera and cornea

Birds have a sclerotic ring that reinforces the sclera

Nictitating membrane (third eyelid)

94
Q

Describe what would be different about a diving bird’s nictitating membrane

A

May have a clear center so they can see under water - protects the glute

95
Q

What does the uveal tunic contain? What is the main difference here in birds compared to mammals?

A

Choroid, iris, ciliary muscles

Muscles in the iris are under VOLUNTARY control

96
Q

If the muscles in the iris are under voluntary control, what does this mean for the pupillary light reflex test?

A

In birds this is NOT considered a reflex.

When a light is put into the eyes, the bird is literally choosing to constrict their iris.

97
Q

What does the neural tunic contain?

A

retina

98
Q

Describe the vascular pectin in the eye

A

Highly vascular comb-like structure that projects into the vitreous humour from the point of the optic disc.

Provides oxygen and nutrients to the eye and removes waste

Can easily hemorrhage with head trauma and will see bleeding from the eyes

Present bc have a reduced number of blood vessels in the retina to allow more photoreceptors (rods/cones)

99
Q

True or false:

Nocturnal species have more cones than rods

A

False
They have more rods than cones

Rods: low light vision
Cones: colour vision

100
Q

Describe how birds have a higher level of visual acuity

A

Reduced number of blood vessels in the retina to allow more photoreceptors

Each cone has a single connection to a nerve fiber

Oil droplet in each cone increases colour reception

Wide spectrum of light wavelengths are able to be perceived

101
Q

Some species have a temporal fovea in the eye, what does this do?

A

Increases binocular vision

102
Q

Describe the ears of birds. What are some main differences?

A

Located on the sides of the head, behind and slightly below the eyes

Do not have much of an external structure

Middle ear only contains ONE bone (mammals have 3) called Columella

103
Q

What makes the hearing of nocturnal owls so highly developed?

A

Contain a operculum: a muscularly controlled flap of skin in the ear that opens and closes to allow focusing of the ear

Also have asymmetrical ear openings to allow them to pinpoint where sounds are coming from

Large eardrums, columellae and cochlea

Well developed acoustic center in the hindbrain

104
Q

Describe the tasting ability of birds

A

Poor sense of taste

Very few taste buds scattered on the sides of the tongue and soft palate

Levels of sensitivity and thresholds to taste vary in species (most can only differentiate types of taste - bitter, sweet, salty)

105
Q

Describe the sense of smell in birds

A

Highly variable in species depending on diet (hunting birds have better sense of smell)

106
Q

True or false:

If you pick up a baby bird from its nest, the mother will abandon it because it smells like humans

A

False

This is a myth, return the bird as close to the nest as possible

107
Q

Describe the two main nerve endings for sense of touch in birds

A

Grandry’s Corpuscle: nerve endings prevalent on tongue, palates and bills of birds

Herbst Corpuscle: nerve endings present on cloaca, legs, wings, uropygial gland and feather bases

108
Q

What is the main difference of the endocrine system of birds?

A

7 major glands plus the pancreas all function similar to mammals

The Bursa of Fabricus is the initial site of B lymphocyte production (rather than in bone marrow in mammals)

109
Q

Because birds have such a fast metabolism, what does this mean for their diet?

A

They require large amounts of food for the high energy demand

110
Q

Beaks or birds vary with

A

Diet

111
Q

The mouth of birds is similar to mammals, containing hard and soft palates, tongue, salivary glands, and taste buds. What is the main difference in some birds?

A

Some species have a soft palate that enlarges into a pouch for temporary food storage (pelicans)

112
Q

What is the main difference of the hard palate in birds, what is it used to evaluate?

A

Hard palate has an opening that communicated with the nasal cavity (choanal slit)

Used to evaluate papillae for nutritional deficiencies

113
Q

Describe how the tongue varies with species

A

May be slightly muscular in some species

May have very few muscles and is moved by muscles of the jaw apparatus in other species

114
Q

Describe the main difference in the esophagus of some species of birds

A

Contains a crop

An expansion of the esophagus over the interclavicular space

This is a place for storage, lubrication, passage, and potential mechanical breakdown of food

Very little digestion occurs here

115
Q

Describe the crop in pigeons and doves at breeding time

A

Mucosal lining can break down and slough off to form “pigeon milk”

116
Q

Describe the crop in insect eating birds

A

Heavy epithelium protects the crops when insects are swallowed alive

117
Q

Describe the stomach of birds

A

Two separated compartments

Proventriculus: glandular compartment - chemical digestion begins here with pepsin and HCL

Ventriculus /Gizzard: muscular stomach - striated muscles grind food (mechanical) ingested grit aids in grinding food here (rocks)

118
Q

What is the pellet

A

Ingested food ground into a pellet in the ventriculus get regurgitated

In birds of prey the pellet is mainly formed of bone, fur, etc. - parts that couldn’t be digested

119
Q

Describe the liver of bird

A

Bilobed - right lobe is larger than the left

120
Q

Describe the pancreas in birds

A

Relatively large especially in fish and grain eaters

Rests in loop of the duodenum

Endocrine portion occupies more tissue mass than in mammals

121
Q

Describe the duodenum in birds

A

Main organ for digestion and absorption of nutrients

Varies in length and thickness depending on diet

122
Q

Describe the ceca in birds

A

Paired sacs at the junction of the small and large intestines in some species

Role in water reabsorption and in bacterial fermentation of cellulose

Contents excreted independent of fecal matter

123
Q

Describe the large intestine in birds

A

Major role in reabsorption of water and minerals

124
Q

Describe the cloaca

A

The end of the digestive tract

Common exit for the digestive, urinary, and reproductive systems

125
Q

Describe the 3 sections of the cloaca

A

Coprodeum: receives excrement from the intestines

Urodeum: receives discharge from the kidneys and genital tracts

Proctodeum: stores excrement and eliminates it

All 3 things get combined/stored before excretion

126
Q

Describe the vent

A

Muscular anus that expels waste products (mute)

127
Q

Waste excreted by birds is called

A

Mute

128
Q

Describe mute

A

Combination of feces (dark) and urine (liquid) with white powdery urate around it

Varies with diet

129
Q

How can mute be used to assess health?

A

Can indicate disease based on colour

Green mute can indicate chlamydial infection (zoonotic), internal parasites or liver disease

130
Q

Why should owners be familiar with the appearance of mute in their birds when they come into clinic?

A

Because stress can change how the mute looks when in clinic

Encourage to take a photo

131
Q

Why can bird not technically vomit?

A

They have no diaphragm

132
Q

Describe tube feeding birds

A

Trachea is a small hole found more rostral in the throat, the esophagus is more caudal

Watch the back of the throat for regurgitation/over flow
- indicates you put too much food in (risk of aspiration since trachea is so close and there is no real epiglottis present)

133
Q

Describe the heart and where it lies in birds

A

4 chambered, right side is smaller and less muscular

Lies in the cranial portion of the thoracoabdominal space (called this since there’s no diaphragm that separates the cavities)

134
Q

Why do birds have large pectoral and brachial arteries?

A

To meet the specific demands of these highly muscular portions of the body (need a lot for flight)

135
Q

Describe the air sacs of birds

A

9 thin walled, high vascular membranes

Connect to the bronchi - some extend into bone cavity

Functions: 
Air reservoirs 
Provide warmth and moisture to air 
Thermoregulation 
Buoyancy
136
Q

Describe the countercurrent heat exchange system in the legs of birds

A

A system of heat exchange in lower extremities through a network of arteries and veins placed closely together

Heats up blood from the extremities before reaching the core to prevent hypothermia, and colder temperatures are sent with arteries back to the extremities

Does not constantly occur (like in summer) - has a sphincter that opens/closes depending on temperature

137
Q

Why should the renal portal system in birds be taken into consideration before injecting medications?

A

Would want to do it in the upper body so the medication can spread systemically before it gets filtered out by the kidneys

138
Q

Since birds have a fast metabolism, what does this mean for heart rate and blood flow?

A

Fast heart rate

More rapid blood flow

139
Q

Electrodes used in electrocardiography are placed on

A

Wings and legs

140
Q

Functions of blood

A

Carry nutrients, oxygen and hormones
Carry metabolic wastes to lungs/kidneys
Control/prevent disease
Regulate body temperature

141
Q

What is the main difference of erythrocytes and thrombocytes in birds compared to mammals

A

They are nucleated

142
Q

What are neutrophils called in birds?

A

Heterophils

143
Q

Describe erythrocytes in birds

A

Oval, nucleated and larger than mammals

Formed in bone marrow in adults or in spleen/liver of some species

Posses hemoglobin

Total number dependent on age, sex, diet, and time of year

144
Q

Describe heterophils in birds

A

(Neutrophils)

Phagocytes

Round with rod shaped red/orange granules

Bilobed nucleus with clumped chromatin

145
Q

Describe thrombocytes in birds

A

Birds do not have platelets, they have THROMBOCYTES

Nucleated cells that act as platelets

Smaller than RBCs with large, round/oval nucleus

Produced by bone marrow in adult birds

146
Q

Describe the syrinx

A

The voice box

Enlargement of the trachea above the sternum

Contains muscles, air sacs, and vibrating membranes

147
Q

Respiratory rate increases with?

A

Activity, heat, flying high

148
Q

Why do birds have such an extensive respiratory system?

A

High demand due to fast metabolism and high energy levels (fliers)

Also aid in buoyancy during flight

149
Q

Describe the trachea of birds

A

Longer in comparison to body than mammals

Provide moisture and heating of inhaled air and aids in sound production

Have cartilaginous rings that surround the entire structure (not C shaped)

May be coiled in some species

150
Q

Vocalization complexity depends on

A

The number of muscles present in the syrinx

151
Q

Describe the bronchi of birds

A

Trachea bifurcates into 2 bronchi

These further divide: 
Mesobronchi: in the lung 
Secondary bronchi: ventrobronchi 
Parabronchi 
Air capillaries (site of gas exchange)
152
Q

Describe the lungs in birds

A
Small and inelastic (do not expand/contract) 
High vascular (bright red) 

Attached to the thoracic vertebrae and ribs

Connect via projections into the bone that put air into the hollow spaces for buoyancy

153
Q

Describe the renal portal system of birds

A

Blood vessels from the legs/lower body, returning to the heart is shunted to the kidneys to get filtered before returning to the heart

154
Q

What is different about a birds trachea? What does this mean for restraint?

A

Have cartilaginous rings that surround the entire structure

Restrain mainly around neck since breath occurs with the chest cavity movement

155
Q

Describe airflow in birds lungs

A

2 inspirations and 2 expirations are required to transport one breath of air through the entire system

Path of one breath/air pocket: 1st breath in, goes into posterior air sacs

1st breath out goes into lungs

2nd breath in goes into anterior air sacs

2nd breath out - air leaves

156
Q

If birds have no diaphragm, how do they breathe?

A

A whole body process driven by the expansion of the chest cavity/ ribs

157
Q

True or false:

There is no mixing of inspired and expired air within birds

A

True

158
Q

Due to their very sufficient respiratory system, what does this mean for inhaled chemicals?

A

Very rapid response and increased sensitivity to inhaled anesthetics

Very sensitive to poisonous gasses or inhaled irritants

Ex. Teflon pans can cause respiratory distress or death
Ex. Canaries used in coal mines - would die due to poisonous gasses before humans did - alert system

159
Q

Describe the respiratory rate in birds

A

Varies with species, activity level, age, sex, time of day, outdoor temp

Smaller birds breathe faster

Birds in flight have higher heart rate

Respiratory rate is generally very fast and very high so not often used as a diagnostic tool

160
Q

True or false:

Intubation of birds is extremely easy

A

True

Trachea is very easily visible

161
Q

Describe how birds thermoregulate

A

Birds do not have sweat glands

Most heat is eliminated through respiration (water evaporated through respiratory system helps cool down)

Can increase this rate by panting or fluttering the upper throat patch with an open beak

162
Q

Why is panting dangerous in birds?

A

Often indicated stress or over heating

Birds exist at a higher temperature compared to mammals, this leaves very little room for temperature changes before proteins begin to denature etc.

163
Q

What are some other methods of decreasing temperatures in birds

A

Bathing

Decrease activity

Some species defecate on their legs to increase evaporative cooling

Adjusting feather position ( proofing to warm) open up bare patches to cool

164
Q

Other methods of raising body temperature in birds

A

Perching on one leg to minimize skin exposure

Tucking head and beak under feather on back

Shivering

Seeking shelter

Some species (humming birds) can enter a temporary night time torpor (state of inactivity) to conserve heat

Countercurrent heat exchange in limbs

165
Q

Describe the urogenital system

A

The urinary and reproductive system in birds

166
Q

True or false:

Female birds only have one ovary on the left side

A

True

167
Q

Describe the salt gland

A

Many marine birds have

Located above each eye and drain into nostrils

Secrete large amounts of sodium chloride (salt)

Helps maintain ideal osmotic conditions in the body while living and feeding in a high salt environment

168
Q

Describe the kidneys in birds

What are the differences compared to mammals?

A

Large paired organ, 3 lobed, lie flush with the back bone

Renal portal system filters blood from lower body (controlled by a valve)

Similar in function to mammals but:

1) no renal pelvis
2) two types of nephrons: looped (similar to mammalian nephrons) and unlooped (similar to reptilian nephrons

169
Q

True or false:

Birds do not have a urinary bladder

A

True

Excrement from kidneys get collected in the urodeum of the cloaca

170
Q

Describe the urine composition of birds

A

Different from mammals:

Higher uric acid concentration (urea is predominant in mammals)

Uric acid eliminated as a white powder in combination with fecal material (usually green or brown with a ring of white around it (urate))

171
Q

Why is the different urine composition of birds more advantageous?

A

More efficient way to get rid of nitrogenous waste:

1) less water loss
2) allows embryo to store large amounts of nitrogenous waste with the confines of the shell without dying (wouldn’t be possible with urea since urea is toxic and uric acid is not)

172
Q

Breeding season in birds is often stimulated by ______. What does this affect in the bird?

A

Increasing day length in parts of the world where seasons are more pronounced

Affects hypothalamus and causes an increased secretion of gonadotrophic hormones

173
Q

Non-breeding animals have very small gonads, which increase in size when?

A

Breeding season approaches

174
Q

How are most birds differentiated by sex

A

Most species have very little sexual dimorphism, so the only way to tell sexes apart is by DNA testing (blood test)

175
Q

Describe the testes and where sperm is stored in birds

A

Testes are bean shaped and located internally

Sperm are stored in a pouch

Seminal vesicle (temp is 4 degrees cooler than body temp) located at the terminal end of the vas deferens

176
Q

The vas deferens carries sperm to the

A

Seminal vesicle and cloaca

177
Q

Describe copulation for males

A

Behavior stimulated by androgens (from leydig/interstitial cells in the testes)

Some species (galliforms, ratites, and ducks) have a grooved penis that assists in sperm transfer

Other species simply bring cloaca together for copulation

178
Q

True or false:

Basic ovarian follicles development and ovulation in birds is similar to mammals

A

True

179
Q

Transfer of the ova into the oviduct is similar in birds to mammals, what differs as the egg passes through the oviduct and uterus?

A

The eggs get surrounded by layers of albumin (egg white) the shell membrane, shell and pigments

This means the ova is the egg yolk in an egg

180
Q

Birth of the eggs is through the

A

Cloaca

181
Q

Describe the 5 sections of the genital tract in females and how they contribute to development of the egg.

A

1) infundibulum: catches the ovum when released from the ovary, fertilization occurs here
2) magnum: secretes albumin
3) isthmus: secretes inner and outer shell membranes onto fertilized ova
4) uterus (shell gland): secrets thin water albumin, the shell and pigmentation, the eggs spend most time here to form egg (uses tons of calcium)
5) vagina: secretes mucus for egg laying and stores sperm for hours to days

182
Q

Describe egg binding/ egg bound birds and why it is considered a medical emergency

A

When the egg fails to pass from the uterus to the cloaca

Since the bird only has one opening for the reproductive, urinary, and digestive systems, when an egg is blocking here it prevents urination and defecation (can die very quickly)

Signs: depression, stop eating, penguin-like gait

183
Q

How is an egg bound bird treated?

A

Anti-inflammatories, topicals, baths, calcium supplements, manual manipulation or surgically by collapsing the egg with a needle through the cloaca

184
Q

How is egg binding prevented

A

Avoid obesity

Watch for vent picking and separate affected birds

Ensure adequate calcium in diet

185
Q

Define clutch

A

The number of eggs laid and incubated

Varies in species (1-20)

186
Q

Describe determinate layers

A

Total number in clutch predetermined by number of follicles developing in the ovary

187
Q

What are indeterminate layers (most birds)

A

Eggs are continuously produced until a set number is reached in the nest

If eggs are removed the bird will continue to lay indefinitely

The signal to stop includes visual tactile and hormonal influences indicating a full clutch (birds literally count)

188
Q

Why are indeterminate layers beneficial with endangered species

A

Will remove eggs and incubate artificially so the bird will continue laying

189
Q

Eggs can be laid everyday, every other day, or every 4-5 days
Some species incubate all at once or as eggs are laid
What can this result in

A

Chicks may all hatch and develop at varying time

Or chicks may all hatch and develop synchronously

190
Q

How do birds incubate their eggs

A

Sitting on the eggs/nest to keep eggs at a certain temperature in order to develop (need to be kept warm and humid)

Females have a “brood patch” - featherless patch on belly where skin folds, thickening and blood circulation create a heat pad for eggs

Time for incubation varies with species (longer for larger birds)

Budgies: 18 days

191
Q

What do the 4 classifications of chicks depend on?

A

Feather coverage
Open or closed eyes
Mobility

192
Q

Describe precocial chicks

Give an example

A

Ducks and geese

Downey feathers
Open eyes
Mobile

193
Q

Describe semiprecocial chicks

Give an example

A

Gulls and terns

Downey feathers
Open eyes
May be mobile but remain in nest
Dependent on parents

194
Q

Describe semialtricial chicks

Give an example

A

Hawks and owls

Downey feathers 
Open eyes (hawks) 
Closed eyes (owls) 
Not mobile 
Confined to nest for care
195
Q

Describe altricial chicks

Give an example

A

Song birds

Little to no feathers
Closed eyes
Not mobile