Avian Flashcards
What is unique to birds and seperates the RA and RV of the heart?
Right muscular AV valve - allows complete emptying of blood from right ventricle
Bird arteries have a low vascular resistance, how do they compensate?
By having a higher BP + stiffer arteries
What is the function of nucleated RBC in birds?
- Helps w toxin metabolism
- Detox functions
- Responds/adapts to hypoxia in high altitudes
How is the avian spleen different from mammals?
Not capable of storing RBCs
RBC production and Hb synthesis are regulated independently
What acts as a baffle to block entry of large particles?
Operculum on the nares of the bird
What is the clinical relevance of choanal papilla?
Can be lost with infection or vitamin A deficiency
Ex: shitty diet (all seed diet)
Birds have an increase in tracheal dead space. How do they compensate?
By increasing tidal vol. and decreasing freq. of respiration
** they take slow but deep breaths of air
What is the clinical relevance of a birds trachea?
Complete ring of cartilage
dont inflate Endotracheal Tube, if you do it could rupture the trachea
What is the vocal apparatus in birds?
Syrinx
What are the 2 types of parabronchi in birds?
Paleopulmonic + Neopulmonic
What are the characteristics of paleopulmonic parabronchi?
- Man gas exchanging bronchi
- 1 way air flow - caudal to cranial
- Long, and lie parallel to eachother
What are the characteristics of neopulmonic parabronchi?
- Short and anastomose profusely
- Bidirectional air flow
Where is gas exchange most effective in birds?
Atria
** expansions in the walls of the parabronchi containing air capillaries
What is the clinical relevance of the lungs in birds when restraining?
Dont place in lateral or dorsal recumbancy!!! this will decrease the lung volume
Name the air sacs in the cranial group and caudal group
Cranial:
(2) Cervical
(1 UNPAIRED) Clavicular
(2) Anterior thoracic
Caudal:
(2) Caudal thoracic
(2) Abdominal
How does the blood gas barrier play a role in gas exchange?
Thin Blood gas barrier + more air capillaries in a given space allows for greater gas exchange
Explain what happens during the first inhalation
Air flows into trachea to the caudal air sacs and expands them
Explain what happens during the first exhalation
Caudal air sacs deflate and move air into the paleopulmonic lungs
Explain what happens during the second inhalation
Air from paleopulmonic lungs move into the cranial air sacs allowing them to inflate
Explain what happens during the second exhalation
The cranial air sacs deflate and push air into the trachea and out of the body
What should you do if you do not see a bubble when you admin fluid to a bird?
STOP AND REDIRECT NEEDLE
no bubble = fluid is going into air sac and can drown the patient
True or false: air sacs participate in gas exchange
FALSE
Parabronchi participate in gas exchange
What is the landmark for finding the lobes of the kidney in birds?
Cranial lobe - cranial to external iliac a.
Middle lobe - between external iliac a. + ischiatic a.
Caudal lobe- caudal to the ischiatic a.
Most birds have what type of nephron?
Reptilian type
Explain the reptilian type nephron in birds
NO LOOP OF HENLE
** cant concentrate urine - urine will by hypotonic/isotonic/dilute
- LOW S.G
reptilian nephrons are smaller and more numerous
What makes up the ring of vasculature / renal portal system?
Cr + Cd renal portal veins
L + R external iliac veins
L + R common iliac veins
When is the valve in the common iliac v open?
During SNS via Epi + NE- diverts blood directly to the vena cava and skips the kidney
allows increased blood flow to the heart during flight
When is the valve in the common iliac v closed?
During PNS - resting and digesting via Ach
Allows blood to entire the kidney
Why do you not want to give injections in the common iliac v?
- If the valve is closed under PNS the drug can go to the kidney and cause acute nephron toxicity
- If valve is open under SNS it can go right to the heart without a chance of being effective to the body
Why are bird ureters so important?
- Secretes mucus which helps excrete urates into the urodeum
Uric acid is the main __________ waste product
Nitrogen
How are urates filtered by the kidney?
Small enough to be freely filtered by glomerulus
Some urates are secreted into the PCT
What do you have to worry about in a dehydrated bird?
Potential for urates to form crystals in PCT or ureter
Dehydration = decreased GFR + BP
- decreased blood flow to kidneys
causes urates in colloid to come out of suspension and form crystals
Where is avian urine and urates stored?
Urodeum
Birds can move waste from the urodeum by retroperistalsis into the LI or colon to help reabsorb what?
- Water reabsorption
- Electrolyte homeostasis
- Nitrogen recycling
- Energy source creation - albumen degraded into AA + peptides that bacteria use to make SCFA for energy
What is an indeterminate breeder?
If you add or remove an egg the bird will lay an extra egg or curtail laying (stop laying eggs)
What is a determinate breeder?
number of eggs in clutch determined at onset of laying and is unchanged by removal or adding an egg
Most birds have a functioning _____ ovary and oviduct
LEFT
In birds, what happens after ovulation fails?
No functional corpus luteum
How can cystic follicles form?
If persistent cells secrete hormones during regression
What makes up the oviduct?
- Infundibulum
- Magnum
- Isthmus
- Uterus
- Vagina
Explain the characteristics of the infundibulum
- Site of fertilization
- Surrounded by left abdominal air sac which helps capture the egg
- 15 min window for sperm penetration before CHALIZIFEROUS layer (Thin but dense layer of albumen) is laid down
What can cause egg yolk peritonitis / egg related coelomitis?
If left abdominal air sac is damaged, infundibulum cant catch the egg and it starts developing in ABD cavity
Where is the majority of the albumen added?
In the MAGNUM
Where is the site of fertilization in birds?
Infundibulum
What forms the 2 shell membranes - inner and outer shells?
Isthmus
What is the function of the cranial portion of the shell gland/uterus?
Plumping the egg!!
Adding electrolytes and water to albumen
What is the function of the distal portion of the shell gland/uterus?
Creates the shell by extracting Calcium from the blood to use for the shell
Egg remains here for 20 hrs
Where is the site for sperm storage?
Fossulae spermaticae
What is the physical process of laying eggs in birds?
Oviposition
If the ovum is fertilized it is termed the __________ and will become the _________
Blastoderm, Embryo
What makes up the yolk?
Lipoproteins and phosphoproteins
main source of nutrition for developing embryo
What is the function of yolk membranes?
Forms a barrier between yolk and albumen
allows movement of electrolytes
What is chalaza?
Twisted strands of ovomucin fibers
Helps hold yolk steady in the center of the egg
What is the function of albumen in the development of the egg?
- Suspends embryo in aqueous enviro
- Nutritional protein source
- Antibacterial properties
What is produced as the egg cools after being laid?
Air cell
What makes eggs red-brown vs blue-green?
Red-brown : PORPHYRINS
Blue- green: BILIVERDINS
What are the 2 main sources of calcium?
Diet and medullary bones
Medullary bone contribution to Calcium is higher when?
During night time when bird is not eating or when bird is eating a low Calcium diet
Calcitonin is produced by _____________ in birds
Ultimobranchial glands
What is essential for translocation of calcium across the oviductal wall?
Calcitriol
How does estrogen play a role in calcium metabolism?
Increased estrogen causes osteoblasts to make medullary bone which makes Ca+
Without Estrogen osteoblasts will make lamellar cortical bone
If a bird is egg bound, why would you want to give a drug that reduces estrogen?
To reduce repro activity + allow less Calcium to be transported to the uterus
