(14) - Avian Renal Physiology Flashcards
(Overview of Functional Aspects of the Avian Kidney)
(blood supply)
- what percent of cardiac output?
- what percent afferent arteriole to glomerulus?
- what percent from venous blood from portal system?
- 10-15%
- 20-35%
- 65%
(Overview of Functional Aspects of the Avian Kidney)
- What is their urine concentrating ability?
- Nitrogen excretion product is 80% what?
- Is uric acid secreted or filtered?
4.
- 2-3X plasma
- uric acid (remainder is urea or ammonia)
- secreted
(read the rest)
do’nt memorize this
(Location in Body)
- embedded in what?
- a depression in what?
- how many main lobes?
- adjacent to what?
- venous vascular ring consisting of what three veins?
- renal fossa
- synsacrum (the boney roof of the pelvis)
- 3
- gonads and andrenals
- external iliac vein, common iliac vein, and cranial and caudal renal portal veins
(Blood Supply - 2 inputs)
(arterial)
- renal arteries - what percent of blood?
- afferent supply to what?
- efferent supply to what?
(venous)
- renal portal supply - unique - 65% of blood
- 15%
- glomeruli
- tubules (as in mammals)
(Avian Nephron Units)
(Lobular Architecture)
- renal lobule and peri-tubular blood supply
(Nephrons - 2 types)
- mammalian type - what capacity?
- reptilian type - what capacity?
- concentrating capacity
- non-concentrating capacity
(Renal Lobule and Peri-tubular blood supply)
- each lobule is a functional unit that drains through a what into a what?
- secondary CD’s coalesce into primary CD’s and then into what?
- medullary cone into a secondary collecting duct
- lobular ureters
(there is no renal medulla or pevis per se)
(Nephron Units: 2 types)
(Reptilian type nephrons)
- consist of a glomerulus and a duct to the ureter
- what percentage of nephrons?
- do they have a loop of Henle?
(Mammalian type)
- long loop, short loop, varying lengh loops
- what percentage of nephrons?
- 80-85%
- no
- 15-20%
urine concentrating similar to that seen in mammals
important note - gradient genereated by Na only - in mammals half of gradient established by urea
(Concentrating Capacity of Avian Nephron)
(osmolality of urine ranges from 2-3X of plasma)
- how comparted to mammalina?
- How much water is reabsorbed by collecting ducts?
- Compensated for by formation of what?
- final adjustments occur where and where?
- 7-8x less
- 95%
- insolbule uric acid
- cloaca and colon
lies in the blood supply thing
65% of blood coming through renal portal supply
blood can be shunted into kidney
blood returing from legs has two options depending on what the renal portal valve does
(Renal Portal Valve)
- Located in what vein?
(Autonomic innervation)
2-3. What are the two types of receptors?
- common iliac vein
- cholinergic - muscarninc receptors
- adrenergic - alpha 2 receptors
(Renal Portal Valve)
- at rest, valve is closed or open? maintained under what influence?
venous blood diverted through tubular circulation
returns to systemic circulation via what and what?
- During fight or flight - valve closed or open?
what happens to blood?
- closed; cholinergic
caudal mesenteric vsin and intervertebral sinuses
- open
blood is shunted directly to the vena cava
(under adrenergic circulation)
(Blood supply to the avian kidney)
- what percent of cariac output?
- what percent of that is arterial? venous via portal system?
- how much of blood passes through glomeruli for filtration?
- so what becomes the main mechanism of excretory fuction (N)?
- 10-15%
- 30%; 65%
- 1/3
- tubular secretion
(Urea vs. Uric Acid)
- mammalian nitrogen disposal = ?
- avian nitrogen disposal = ?
- urea
- uric acid
(Uric Acid)
- nitrogenous waste (NH3) excretion pathway (as opposed to urea)
- produced primarily where?
- secreted in what?
- is it soluble in blood at normal conc and body temps?
- precipitates under what conditions?
- in liver (energetically expensive)
- poximal tubule (hgh conc in colloidal form in lumen)
–> urates (salts of uric acid)
moved by peristalsis down ureter
- yes
- high conc or cooling
(secretion not affected by dehydration (i.e. no pre-renal azotemia)
(Advantages of Uricotelicism)
- combines with proteins to form what?
- conserves what?
- Allow what inside egg?
- insoluble Urates
- water
- development inside egg - prevents accumulation of toxic metabolic products
(Physiology)
- arterial bllod flows through what?
- venous blood portal supply flow though what?
- glomeruli (filtration) - 30%
- tubular capillary beds (secretion, reabsorption) 70%
(overall kidney regulation - 4 factors)
1-4. what are the four factors?
- renin-angiotensin system - aldosterone
- AVT (arginine vasotocin) - Avian ADH
- autonomic
- autoregulation
(Extra-renal Water-balance)
(cloaca/colon)
- do what?
filtered water from what?
ingestinal water with what?
(Nasal Salt glands - marine birds)
- allows excretion of what?
- water recovery
- kidney
- ingesta
- NaCL consumed in salt water that is beyond ability of kidney to excrete
(Clinically)
(utility of mammalian type assessments)
- urea (BUN) usuable?
- creatinine useable?
- urinanalysis: minimally useful because of what?
(Uric acid is the primary means (<5 mg/dl) - of measuring kidney function
- no
- no
- post-renal processing (can examine for glucose, sediments, casts, wbcs)
carnivorous birds get increase in uric acid production because their is nitrogen in what they eat (get post-prandial elevation)
need to wait a while before taking this value in raptors
he stressed aminolycosides here
