Birds Flashcards
(89 cards)
1
Q
What are 4 shared characteristics of birds and reptiles?
A
- Scales on beak, legs and feet
- Single occipital condyle
- Single middle ear bone
- Jaw bone of 5 fused bones
2
Q
Describe the external features of the head.
A
Ear lobe, comb, wattle and, in the male turkey, areas on the upper beak. These enlargements are mainly for courtship and display. These areas are very highly vascularised so appear very red due to thin epidermis.
3
Q
What are ceres used for?
A
Ceres in budgies used for sex differentiation. Crusty in females in breeding season. Male = blue, female = brown
4
Q
Name and describe the 3 foot morphologies in birds.
A
Anisodactyl – chickens, perching, grasping prey
Zygodactyl – parrots, climbing
Palmate – ducks, swimming/paddling
5
Q
Describe the avian eye.
A
- Large, beady eyes
- Well-developed transparent 3rd eyelid/nictating membrane
- Lower lid more mobile
- Blinking mainly by nictating membrane
- Iris usually dark – except owls and gannets
- Scleral ossicles visible on radiographs and skeletons, and gives shape to the eye
6
Q
What is Marek’s disease?
A
A virus of birds that attacks the neurological system and cause a changes in pigmentation causing it to reduce and pupil size.
7
Q
How does eye shape differ?
A
Flat in parrot
Globose in chicken
Tubular (useful for nocturnal sight) in owl
8
Q
What is the location and role of pectin in the avian eye?
A
Pectin in the large posterior chamber that provides nutrients to the fluid in the tissue within.
9
Q
Describe the structure of the beak.
A
- Replaces the lips and teeth of mammals
- Heavily keratinised epithelium overlying vascular dermis above the bone
- Rhamphotheca-keratin layer: upper part rhinotheca and lower part gnathotheca
10
Q
How do waterfowl have modifications in the beak and tongue?
A
Lamellae present on lateral beak and tongue. Act as filter feeders to allow as much food from water to be taken into the mouth.
Casque of hornbill and pouch of pelican are other specialisations.
11
Q
What are 6 functions of the feathers?
A
- Protect the avian skin
- Provide insulation and waterproofing
- Essential for flight
- Courtship displays
- Hearing and echolocation
- Grouse and desert species can store water in feathers and take it back to nest
12
Q
Name and describe the role of the different feather types.
A
- Main flying feathers are primary and secondary remiges on the manus and ulna respectively.
- Rectrices/tail feathers attach to the pygostyle on the skeleton and are for braking and steering.
- Coverts feathers are feathers that give shape to the body and are found all around the body.
13
Q
What are podotheca?
A
Podotheca are areas of the legs that are highly keratinised with no feather cover that are to withstand the forces of landing.
14
Q
What is patagia?
A
- Wing web
- Forms leading edge of the wing
- Propatagial muscles and ligament
15
Q
What are the venepuncture sites in birds? Which are best?
A
- Deep ulnar vein – basilic/cutaneous vein – cutaneous at elbow
- Right jugular vein
- Medial metatarsal
- Toe-nail clipping
Deep ulnar vein/basilic/cutaneous vein and right jugular, as the other 2 can be painful.
16
Q
What is the function of the uropygial gland?
A
- Papillae secretes an oily secretion that is used to maintain feather condition and waterproofing but also acts as a barrier to bacteria and fungi.
- So few birds can skin conditions/infections
- When a bird preens and puts its head towards its tail it is releasing some of the oil from this gland to help maintain condition.
17
Q
Describe the shape and features of the avian skull.
A
- Pyramidal in shape and brain is pushed into occipital region
- Scleral ossicles
- Mandible fits inside the maxilla to create snipping action.
- The 5 bones of the mandible are fused together caudally and articulates with the articular bone.
- Articular bone articulates with the quadrate bone, which is more upright/vertical, which gives the bird a wider gape.
18
Q
How do nasal apertures vary between avian species and why?
A
Very large nasal apertures in the land dwelling pheasant. They are oval in shape and are very large orbits divided by a very thin septum. Gannets are water birds so have smaller apertures to reduce the amount of water that enters during diving.
19
Q
What is prokinesis in birds?
A
- There is depression of the mandible, leading to rotation of the articular bone, causing the jugular arch to rotate and causes elevation of the maxilla.
- Craniofacial hinge joint
20
Q
How does cervical vertebrae vary between avian species?
A
- 14 cervical vertebrae in chickens
- 25 in swans
- Neck tends to be longer in waterfowl so they can reach the uropygial glands
21
Q
How does the sternum vary between avian species?
A
Large keeled sternum in carinates. Keeled sternum much more prominent in birds that are good at flying. Pheasants or chickens are not good fliers but can fly so do have a prominent keel. In ratite, they have much flatter, broader sternums without prominent keel, but ratites have well developed legs for running on land.
22
Q
What is the notarium?
A
Fused thoracic vertebrae. Help the chest withstand the forces generated by the wings during flight. There is 1 free thoracic vertebrae that holds a synovial joint in front and behind it that act as a weak point in the skeleton. Can lead to kinky back, particularly in birds that grow quickly in intensive systems.
23
Q
What is the synsacrum?
A
Very large structure that is open ventrally to allow the passage of eggs in the female. Its fusion is the fusion of a final couple of thoracic, lumbar and sacral vertebrae with the pelvis. It is responsible for supporting the pelvic girdle, which like the pectoral girdle, is entirely osseous in birds and reptiles.
24
Q
Describe the avian limbs.
A
- Reduced manus
- Tibiotarsus and tarso-metatarsus. Some of the features of tibia, tarsus and metatarsals are incorporated. This is for extra stability in the legs to withstand landing.
25
What is the pygostyle?
Fusion of the last vertebrae. Rectrices tail feathers attach here.
26
What is the furcula?
2 clavicles are fused into the wishbone and it is known as furcula. This works during flight to help return some of the elastic energy in downbeat of the wing to help bring the wing back up using minimal amounts of muscle energy.
27
What is kinky back?
Ankylosing spondylolisthesis
Free synovial point in the notarium. Deterioration in vertebral points when birds grow very quickly. Degeneration due to weight gain and repetitive motion. Vertebrae slip with some degree of new fusion between the bones.
28
Describe the avian scapula.
Very long and thin scapula that comes considerably across the ribcage.
29
Describe the avian coracoid bone.
Comes off the sternum. (In mammals we have the coracoid process coming off the medial aspect of the supraglenoid tubercle).
30
Describe the avian humerus.
Pneumatised bone, meaning they are extensions of the airsacs that would extend into it.
31
Describe the avian radius and ulna.
Smaller in comparison to the ulna in birds.
32
How many major and minor metacarpal bones are there?
2
33
What is pinioning?
removing the hand like feature of the bird to render it flightless. Illegal but legal done by a vet with anaesthesia.
34
Describe avian bones and problems associated with them.
Cortical bone is very thin to allow for light bones for flight.
If bird breaks their humerus, it is problematic because any metalwork put in would add weight and also add infection that could be introduced into the respiratory system due to the airsacs.
35
Name and describe the 2 flight muscles.
Supracoracoideus – responsible for upbeat of the wing. Inserts on the dorsal humerus because its tendon runs through the triosseal canal to allow muscles that are ventral to work in opposition.
Pectorals – responsible for downbeat of the wing. Insert ventrally on the humerus.
36
What is the triosseous canal?
Triosseal canal formed from the scapula, humerus and coracoid. Allows different actions because tendon of supracoracoideus runs through this foramen.
37
How do flight muscles vary between avian species?
Flight muscles are white in chickens as they are not good fliers but is normally very red in birds that are better fliers due to myoglobin content.
38
Describe the avian respiratory system.
- For gaseous exchange, vocalisation and thermoregulation
- Small, fairly rigid lungs that undergo very little volume change
- Extensive air sacs not involved in respiration but allow continuous airflow
- No diaphragm
39
What is the path of airflow in the upper respiratory system?
External nares > choanae > glottis > trachea
40
Describe the structure of the trachea.
- Long for mobility
- Complete interlocking cartilage rings. This adds a lot of resistance to the air but this is minimised by the tracheal diameter being wider than it is in mammals. So dead space in air is quite high but overcome by them having very slow respiratory rate.
- Ends in syrinx. This is where birds create song. The equivalent of the larynx in mammals is here.
41
Describe the syrinx.
- No vocal chords
- Tympaniform membrane
- 5 pairs of syringeal muscles in songbirds
- Site for bacterial or fungal infections, which can be noticed by owners as a change in voice
42
What are the species variations in syrinx?
Some, such as Lyre birds can mimic sounds from their environment.
Osseous bulla in ducks and swans, a hollow area of the syrinx that is used to make this quacking sound as a resonance chamber. More prominent in male ducks/mallards. So can be used for sex determination in monomorphic species.
43
Describe the avian lungs.
- Rigid compared to mammalian lungs
- Small, do not change much in volume
- No alveoli
- Each primary bronchi enters the lung and then they run the entire way through the lung tissue.
- Once in the lung tissue, they are referred to as the mesobronchi.
- They then branch off into tubes called the parabronchi, which are the site of gas exchange.
- Septum pushes lungs very dorsally against the ribcage.
- Unidirectional airflow through the lungs.
44
What are 2 roles of air sacs?
- Is able to act as an air store to continuously pass air over parabronchi
- Reduce heat created by flight
45
How many air sacs are in birds?
8-10. Bilateral. Cervical, clavicular, cranial and caudal thoracic and abdominal air sacs in general
46
Describe air flow in air sacs.
Airflow is bidirectional through air sac system and no gas exchange occurs, just act as bellows.
Trachea > lungs > in air sacs > out air sacs > lungs > trachea
2 breathing cycles, one inspiratory and the other expiratory, for air to exit. Unidirectional, caudal to cranial.
47
What are the features of the avian oropharynx.
- Choana – internal nostrils
- Infundibular cleft – opening of auditory tubes
- Laryngeal mound
- Mechanical papillae directed caudally to push food towards oesophagus (no glottis)
- Triangular tongue
48
What is the structure of the oesophagus?
- Deviated right
- Enlarged at thoracic inlet to form crop
49
Describe the function and structure of the crop.
- Large in grain/nut eating birds (granivorous birds). Crop acts as a food store and then later they digest them safely
- Small in fish eaters
- Fusiform enlargement in waterfowl – spindle shaped
- Produces ‘crop milk’ – in pigeons for example, both males and females can make crop milk, which is stimulated by prolactin, and feed this to young.
50
Describe the structure of the avian stomach.
- Glandular stomach/proventriculus: produces hydrochloric acid and mucous.
- Muscular gizzard/ventriculus: replaces the function of mammalian teeth and grinds up grains. Birds will also eat bits of grit and stone to help with mechanical digestion.
- In carnivorous birds, there is less distinction between the proventriculus and the ventriculus.
- Can be less muscular in psittasines.
- Koilin lining – thick glycoprotein layer that is continually formed to help stomach lining resist the abrasion of mechanical breakdown. Is stained yellow due to bile pigment.
51
Describe the avian liver and gallbladder.
2 lobes. Very closely associated with the heart.
Gallbladder on visceral surface of the right lobe. Birds produce biliverdin rather than bilirubin so gall bladder may appear green in any liver problems.
52
Outline the digestive tract.
- Duodenal double loop
- Pancreas between double loop of duodenum
- Jejunoilium
- Vitelline diverticulum – yolk sac remnant between ileum and jejunum
- Ceca
- Colon
- Rectum to coprodeum at cloaca
- Vent
53
What are ceca?
Paired ceca in granivorous birds. Arise at junction of ileum and colorectum.
54
What is the Bursa of Fabricus?
In dorsal wall in immature birds. Is a lymphoid structure, uses antibodies through the main defence but involutes at 2-3 months of age.
55
Describe the cloaca.
Bell shaped pouch at end of rectum. Termination of urinary, reproductive and digestive systems:
- Copradeum
- Urodeum
- Proctodeum
56
Describe the avian testes.
- Paired, bean shaped testes
- Pale coloured
- At cranial pole of kidney
- Close to aorta/vena cava medially
57
Why is it difficult to visualise avian testes?
Difficult to visualise out of breeding season as they are smaller and the tissue can even be reabsorbed. Adaptation to keep bird light for flight.
58
Describe the avian phallus and the species differences.
- Found in proctodeum
- Not present in parrots finches, pigeons, birds of prey
- So reproduce via cloacal kissing, where the male and female are close together and there is transfer of semen to the inverted cloaca of the female into the oviduct
- Solely reproductive where present
59
Describe the avian ovaries.
- Ovary lies at cranial tip of kidney
- Large orange follicles
- Only left functional ovary. Right ovary vestigial/fails to develop
- Breeding cycle linked to light/season/food availability
- When a follicle erupts, it will develop of white line called a stigma, showing blood vessel shave departed and the follicle will erupt and caught by the infundibulum.
60
What are the functions of the oviduct?
- Conducts fertilised ovum to cloaca
- Adds many nutrients
- Encloses embryo in shell
61
What does the oviduct consist of?
- Infundibulum – catches follicle
- Magnum – produces most albumen. Longest part and is tubular
- Isthmus
Held by mesosalpinx
62
Describe the avian uterus and vagina.
- Egg shell production occurs mostly in uterus.
- Uterus and vagina are not analogous in mammals.
- Egg held there for 20 hours and is separated from the vagina by a small sphincter.
- Glands around this area can store semen for later fertilisation.
63
Describe the urodeum and coprodeum.
Urodeum – opening of ureters and genital ducts
Coprodeum – opening of rectum
64
Describe the proctodeum.
- Separated from urodeum by uroproctodeal fold
- Contains Bursa of Fabricus
- Site of B-lymphocyte production and differentiation
- Some species houses male phallus
65
Describe the avian kidneys.
- Renal portal system
- Paired, large, retroperitoneal
- Deep in renal fossa of synsacrum
- Cranial, middle and caudal parts
- No renal pelvis
- Cranial, middle, caudal renal arteries
- Fewer loops of Henle and cannot concentrate urine much above blood levels.
- Urine mixes with faeces and this is when water reabsorption can occur.
66
Do birds have bladders?
No
67
What are salt glands in sea birds?
- Salt sneezed out of nostrils or salt glands across the beak
- Prevents salt getting into bloodstream
68
Which 3 bones make up the triosseous canal and what tendon passes through here?
Scapula, humerus and coracoid. Allows different actions because tendon of supracoracoideus runs through this foramen.
69
How many occipital condyles are there in birds?
1
70
Which part of the wings are the primary and secondary feathers attached to?
Primary attach to manus. Secondary attach to ulna.
71
Which feathers guard the external auditory meatus in birds?
Covert feathers
72
What is the function of the tail feathers?
Used for braking, steering and balance.
73
How many digits are present in anisodactyl?
4. 1 posteriorly and the others anteriorly.
74
What is the differences between the feet of a hen and a cockerel?
Spur on cockerel and lack of spur on hen.
75
How many chambers does the avian heart have?
4
76
Which regions produces albumin?
Magnum
77
Which regions does an egg become calcified?
Isthmus
78
How many primary feathers are there?
11
79
Which other 2 skin glands are present in birds?
Aural and vent glands. There are no sweat glands so birds regulate temperature through gular fluttering, exposing apteria and panting.
80
What are the adaptations of parrots?
- Parrot beak differs from other species. Have incredibly strong beaks, used for gripping branches as well as breaking into and crushing hard nuts and seeds.
- Parrots are zygodactyls, with toes pointing forward and 2 pointing back. This aids with holding onto objects, such as branches. The skin on their feet is scaley and helps to strengthen them.
81
What is the propatagium and its function?
- Propatagium, forming the leading edge of the wing and spanning the shoulder and carpus.
- Beneath the skin and covert feathers are the propatagialis brevis muscle and propatagial ligament.
- Function: essential for producing aerodynamic lift for flight.
- Clinical use: subcutaneous injections.
82
What is the perching mechanism?
Weight of the body causes flexion of digits to allow perching.
83
Why are the cornified scales on the leg paler in productive laying hens?
The pigment is incorporated into the yolk.
84
Describe sex determination in birds.
Female: fast feathering, primaries are longer than coverts
Male: slow feathering, primaries are the same length or shorter than coverts
Evert vent lip: female is conical and rounded in male
85
What is different about avian trachea?
Aves have complete tracheal rings
86
What is the function of the ceca?
They contain gram-positive bacteria and protozoa, which help to digest cellulose in herbivorous species.
87
Describe the structure of the avian brain.
- Large optic lobes
- Lack of sulci and gyri in the cerebellum
- Relatively large size of cerebellum
88
Describe the peripheral nervous system in birds.
- Brachial plexus is cranial to the heart and deep to the trachea, oesophagus and lumbosacral plexus. It is exposed by removing the kidneys.
- Vagus nerve – beside the jugular, which are in the abdomen, along the ventral proventriculus.
- Intercostals seen by removing lungs
- Intestinal nerve in the mesentery and sciatic nerve on the medial aspect of the thigh
89
What can Marek's disease be indicated by?
Enlargement of the peripheral nerves
