Anatomy and physiology of birds 2 Flashcards
1
Q
What is the advantage of birds having a bill/beak?
A
It reduced weight
2
Q
What is the bill/beak anatomy dependent on?
A
Lifestyle
3
Q
What are bill/beaks made of?
A
Bony projections covered with a keratinised sheath - rhamphotheca
4
Q
What is the upper beak called?
A
Rhinotheca
5
Q
What is the lower beak called?
A
Gnathotheca
6
Q
Why do beak injuries often need vet treatment?
A
They have blood and nerve supplies
7
Q
What feature of the beak often causes abnormalities?
A
Continually growing
8
Q
How would you describe the abnormality scissor beak?
A
Upper and lower portion of the beak do not line up
9
Q
How would you describe the abnormality parrot beak?
A
Upper beak rests on or inside lower beak
10
Q
How would you describe the abnormality simple overgrowth?
A
Abnormally long (usually upper) beak
11
Q
What is the cere?
A
A waxy structure at the base of the beak
12
Q
Which birds have a cere?
A
Raptors, parrots and owls
13
Q
In the species that possess them, what do the cere house?
A
Nares (in owls the nostrils are distal to the cere)
14
Q
What can the cere be used for in budgies?
A
Sexing
Blue = male
Pink/beige = female
15
Q
What does the structure of the tongue depend on?
A
Diet
16
Q
Describe the glottis of birds.
A
It is easily identifiable making intubation easy
17
Q
Describe the position of the oesophagus.
A
Lateral to the glottis, on the birds right
18
Q
What is the choanae?
A
Opening on the roof of the oral cavity from the nares (fits over the top of glottis when mouth closed)
19
Q
What can the choanae be used for?
A
Useful site for swabbing for respiratory disease
20
Q
Describe choanal papillae.
A
Choanal papilla are small spiky projections which are located on the roof of the mouth.
21
Q
What can the blunting of choanal papillae be an indication of?
A
Nutritional deficiencies - specially hypovitaminosis A
Chronic respiratory disease
22
Q
What is the crop?
A
Out pouching of oesophagus.
Muscular sac like structure in proximal oesophagus
Not present in all birds
Varies in size
Highly elastic
23
Q
What is the function of the crop in birds?
A
Acts as a temporary food ‘store’
24
Q
Why is the crop different in pigeons?
A
It is a double sac.
It produces ‘crop milk’ - fat filled epithelial cells sloughed off and regurgitated to feed young, influences by prolactin
25
Describe sour crop.
Yeast infection/overgrowth leading to thickened crop and disruption of normal bacterial population.
26
Describe crop impaction.
Failure of food to leave the crop and enter the proventriculus.
Often caused by ingestion of stringy material (grass) or sometimes due to disorders of motility
27
What are the two sections of a birds' stomach called?
Proventriculus and ventriculus (or gizzard)
28
What is the function of the proventriculus?
Glandular stomach.
Secretes digestive enzymes and caused enzymatic digestion of food.
29
What is the function of the ventriculus?
Muscular stomach.
Caused mechanical breakdown/digestion of food.
Sometimes contains particles of ingested grit to aid grinding of food material.
30
What is the difference between the small intestine of herbivores/omnivores and carnivores?
Herbivores/omnivores = highly coiled
Carnivores = shorter and simpler
31
Where is the pancreas located?
Between the arms of the duodenal loop
32
What is Vitteline/Mekels diverticulum?
Considered to be the junction between jejunum and ileum
Remnant of yolk sac attachment
33
What is the main function of the large intestine in birds?
Reabsorption of water and electrolytes
34
What are the ceca in birds?
Outpouchings of large intestine - histologically similar to large and small intestine
35
Describe the ceca in galliformes (chickens).
Large and well developed
36
Describe the ceca in passeriformes (song birds).
Small
(Lymphoid ceca)
37
What is the cloaca?
Terminal portion of reproductive tract urinary tract and gastrointestinal tract.
38
What does the cloaca receive?
Waste from GI and renal system
Products of reproductive tract
39
What are the three cloacal regions called and what do they receive/do?
Coprodeum - receives faeces and digestive waste from intestine
Urodeum - receives ureters and products of reproductive tract
Proctodeum - houses bursa of fabricus on dorsal midline
40
What is the external opening of the cloaca called?
Vent
41
Describe the liver of birds.
Bilobed (right larger than left)
Located caudal to the heart (no diaphragm) and close to proventriculus and spleen
Gall bladder present
42
Describe the pancreas of birds.
Usually located within the duodenal loop.
Secretes number of enzymes involved in the digestive process.
Exocrine = amylases, proteases, lipases
Endocrine = insulin, glucagons, somatostatin
43
Describe the GI tract of seed eaters.
Well developed crop, proventriculus and gizzard. Long intestine. Distinct caeca.
44
Describe the GI tract of fruit eaters.
Shorter intestine. Caeca less distinct.
45
Describe the GI tract of meat/fish eaters.
Caeca and gizzard basic. Well developed pancreas and proventriculus.
46
Describe the kidneys of birds.
Paired retroperitoneal organs (as in mammals)
Each kidney has 3 lobes - cranial, middle and caudal
47
Where does the urine of birds go to from the kidneys?
Through the ureters to the cloaca (no urinary bladder)
48
Describe the nephrons of birds and what this means for them.
Have both reptilian and mammalian type nephrons.
Can switch between them depending 'on the need for water concentration.
49
What is the mechanism for reuptake of water in birds?
Retrograde flow into colon from cloaca
50
What is the end product of metabolism in birds? Where is this formed and excreted?
Uric acid
Formed in liver
Excreted via glomerular filtration and tubular secretions as white 'precipitate' within urine
51
Describe normal bird urine.
Uric acid precipitate mixed with copious mucus.
Urates should appear white, with clear watery urine.
52
Describe the testes of birds.
Paired testes located within the abdominal cavity at the cranial lobe of the kidneys.
The size of them depends on the time of year - increase in size in breeding season.
53
When does the majority of spermatogenesis occur in birds?
During the night when temperatures are lower.
The testes are functional at body temperature (40 - 41 degrees C)
54
Which accessory sex glands are present in birds?
None
55
Compared to mammals, describe the epididymis of birds.
Short
56
Compared to mammals, describe the ductus deferens of birds.
Main storage site for sperm
(little capacity for storage as the testes enlarge so much in breeding season)
57
Describe the phallus of ducks, geese and ratites.
Intromittant organ - analogous to the penis
58
Describe the phallus of chickens, other fowl and passerines.
Non intromittant
Achieve fertilisation by touching phallus to the cloaca of the female
59
Describe the phallus of psittasines.
No phallus.
Fertilisation occurs by eversion of the cloaca containing papillae.
60
Describe the ovaries of birds.
Only left ovary and oviduct fully developed and functional.
Right ovary and oviduct regress (except in some raptor species)
Ovary located cranial to kidney, tightly attached to dorsal body wall and adhered to caudal vena cava.
61
What are the 5 function regions of the female reproductive tract of birds?
Infundibulum
Magnum
Isthmus
Uterus (shell gland)
Vagina
62
What does a mature ovary contain?
A bunch of follicles
Resembles a cluster of grapes
Can contain up to 4000 ova
63
Describe development of follicles in female birds.
Sequentially
64
Describe follicular stasis.
Inappropriate maturation of follicles within the ovary without ovulation
65
What is excessive egg production a result of?
An overactive reproductive tract
66
Describe egg binding.
Where an egg takes longer than normal to pass out of the reproductive tract.
Can lead to dystocia (failure to lay)
67
What are continual layers?
Hens are continual layers (next follicle ovulated about 30 mins after laying)
68
What are determinate layers?
Pet birds
Produce a clutch and then egg laying ceases for a period
69
What are indeterminate layers?
Cockatiels
Produce clutches but also have the ability to 'replace' a lost egg - hence important not to remove these from a pet bird (or replace them with something)
70
What occurs in the infundibulum of female birds?
Receives ovulated follicle
Fertilisation takes place in this region - fertilised gamete lies on surface of yolk.
Site of formation of chalazae (albuminous cords which hold yolk in pace)
71
How long does an 'egg' spend in the infundibulum?
15 - 17 minutes
72
What occurs in the magnum of female birds?
Egg white (albumin) develops around follicle/yolk
73
How long does an egg spend in the magnum?
180 minutes (3 hours)
74
What occurs in the isthmus of female birds?
Shell membranes are produced
75
How long does an egg spend in the isthmus?
75 mins
76
What occurs in the uterus/shell gland of female birds?
Calcification of the shell
77
How long does an egg spend in the uterus/shell gland?
20 hours
78
What occurs in the vagina of female birds?
Adds egg cuticle
Also site of sperm storage - sperm storage tubules
79
How many chambers does a birds heart have?
4 chambers
80
What do birds have nucleated red blood cells?
Evolution
Birds evolved in a period where the earth's oxygen levels were higher
81
What do birds have higher cardiac output and cardiac size compared to mammals of similar body mass?
Flight is metabolically demanding
82
Describe heart size compared to body mass and why this is the case.
Heart size is inversely proportional too body mass. As small birds have to flap their wings more.
83
What is the expected blood pressure of birds and how does this compare to mammals of a comparable size?
180/140 mmHg
Higher than mammals
84
What can the heart rate reach in birds?
800 bpm
85
What can respiratory rate be easily and significantly altered by?
Handling
86
What do birds have as well as lungs?
System of air sacs
87
What structure do birds not possess?
Diaphragm
88
What expands the thoracic cavity? Why is this unique in birds?
Thoracic and abdominal muscles expand thoracic cavity. The lungs are fixed and do not expand.
89
What feature allows for a range of vocal sounds in birds?
Syrinx
90
What is the syrinx composed of?
Last few tracheal rings
First few left and right bronchial rings
Central 'tympanic' membrane
91
Describe the upper respiratory tract of birds.
Air drawn in through nares and travels through conchae (rostral, middle and caudal) and paranasal sinuses - filters and warms air.
92
How does the nasal cavity communicate with the oral cavity?
Via a slit called the choanae
93
What is the second smaller slit caudal to the choanae?
Opening into the middle ear
94
Describe the lower respiratory system of birds.
Trachea bifurcates into primary bronchi (left and right). Primary bronchi further subdivide into secondary bronchi, then parabronchi.
Parabronchi open into atria which contain air capillaries (analogous with alveoli)
95
What is the name of the system birds breathe using and what does this mean regarding respiratory cycles?
Birds breathe using a 'one way system'.
Two complete respiratory cycles are required for inhaled air to be exhaled again
96
How many air sacs do most birds have?
9
97
What are the names of all the air sacs in birds?
Interclavicular air sac x1
Cervical air sacs x2
Anterior thoracic air sacs x2
Posterior thoracic air sacs x2
Abdominal air sacs x2
98
What is the function of air sacs in birds?
Push air through lungs
99
Describe the lungs of birds.
Site for gas exchange.
Parabronchial lungs - system of narrow tubes which allow air flow in one direction only. These are surrounded by capillaries (gas exchange).
100
What happens during inspiration in birds?
Air flows down trachea, along bronchi, into posterior air sacs (posterior thoracic/abdominal).
Simultaneously air moves from lungs parabronchi into anterior air sacs (anterior thoracic/interclavicular/cervical)
101
What happens during expiration in birds?
Air flows from posterior air sacs through parabronchi.
Air from anterior air sacs expelled through trachea.
102
What are the air sacs extensions of?
Muco-serous extension of the secondary bronchi
103
What do some air sacs extend into?
Hollow pneumatic bone
104
Which bones in birds are pneumatic bones?
Skull, humerus, clavicle, keel, pelvic girdle, lumbar and sacral vertebrae.
(Not found in all birds, and varies with species)
105
Describe the blood supply of air sacs.
Poor
106
What results in air sacs being susceptible to bacterial/fungal infection?
They are thin walled and have a poor blood supply
107
What can trauma to air sacs result in?
Development of sub-cutaneous emphysema
108
Which lymph nodes are present in birds?
None
109
Where are immune cells produced in birds?
In the embryonic liver, yolk sac and bone marrow
110
Where do immune cells mature in birds?
Primary lymphatic organs
111
Where are B cells produced in birds?
Bursa of Fabricus
112
Where are T cells produced in birds?
Thymus
113
When does bone marrow produce immune cells?
When other organs have receded
114
Where is the thymus located?
Neck
Recedes in adults
Variable size
115
Where is the Bursa of Fabricus located?
Dorsal cloaca
Recedes in adults
Variable size
116
What are the secondary lymphatic tissues in birds?
Gut-associated lymphatic tissues (GALT) - caecal tonsils
Respiratory associated lymphatic tissues (RALS)
Conjuctiva associated lymphatic tissues (CALS)
Spleen
Harderian gland - located close to eye
