URINARY SYSTEM MIDTERM (PART 2)

How many lobes do avian kidneys have?

Three lobes

What structural feature is absent in avian kidneys?

Clear demarcation of the cortex and medulla

What part of the kidney is missing in birds that is present in mammals?

Renal pelvis

What is a key structural difference between reptilian and mammalian nephrons?

Reptilian nephrons lack the loop of Henle

Where are mammalian nephrons located in the kidney?

both the cortex and medulla

How do reptilian nephrons respond to heavy salt loads?

They shut down

What is the function of the loop of Henle in mammalian nephrons?

It helps concentrate urine

Which type of nephron operates at a high filtration rate?

Mammalian-type nephrons

Where is the majority of uric acid secreted in reptiles?

In the tubules of reptilian-type nephrons

What is the function of the renal portal system in avian?

It supplies venous blood to the renal tubules before mixing with efferent arteriolar blood from the glomeruli

Where does the renal portal blood come from?

From the hind limbs via the external iliac and sciatic vein

What is post-renal modification of urine?

The alteration of urine after it leaves the ureters due to exposure to the cloaca, colon, and ceca membranes.

How does post-renal modification occur?

Through retrograde flow caused by reverse peristalsis.

Why do birds excrete uric acid instead of urea?

To conserve water, especially during embryonic development inside the eggshell.

Why is uric acid a better nitrogenous waste product for birds?

insoluble In water and less toxic

Which birds have a urinary bladder?

Ostriches and rheas

What form of nitrogenous waste do birds excrete?

Urate (uric acid) instead of urea

Why does uric acid require little water for excretion?

Because it is largely insoluble, allowing water conservation in dry climates.

What happens to urine and urates in the large intestine?

Microorganisms recover the protein coat, and What are the three components of avian droppings?ater, electrolytes, free amino acids, and sugars are reabsorbed.

What are the three components of avian droppings?

Feces, urates (uric acid), and urine

Where do the feces in avian droppings come from?

colon

What color are urates in bird droppings?

Chalky white

What does the urine in bird droppings look like?

clear

(term) The normal condition of storing urine in the bladder while it fills. There is still tonic contraction that closes the sphincter.

Urinary continence

(term) dribbles urine at frequent intervals instead of permitting the bladder to fill.

An incontinent animal

refers to an “increased urine output”.

Polyuria

means “decreased output”.

Oliguria

a condition of “no urine output”.

Anuria

The term that is used to denote difficult or painful micturition.

Dysuria

slow, dropwise, painful discharge of the urine caused by spasm of the urethra and the bladder (clinical sign of Feline urologic syndrome).

Stranguria

it affects urine concentration, the outcome is influenced by?

Both cortical and juxtamedullary nephrons

The thin descending limb, the thin ascending limb, and the thick ascending limb of the loop of Henle

Have the same lumen diameter

Innervation to the kidney is provided by

Groups of fibers with both motor (efferent) and sensory (afferent) activity

The following values were obtained in a renal physiology laboratory where RBF, RPF, GFR, and FF were being measured but their identity has been lost: 16mL/min per kg; 3.36mL/min per kg; 8.64mL/min per kg; 0.35. Their reassigned identity should be?

RBF, GFR, RPF, FF

What would be the response of a renorenal reflex following a left ureteral obstruction?

Mechanoreceptors in the left kidney activate a reflex to increase activity of the right kidney

Which one of the following would have the highest values for hemat- ocrit and plasma protein concentration?

Blood in the efferent arteriole

Generally speaking, protein molecules are normally restricted from filtration through the glomerular membrane because of?

Their size and polyanionic nature

A plasma glucose concentration of 300mg/dL and a urinalysis that is positive for glucose has been found in a dog. Which one of the following would be a likely clinical sign?

Polyuria and polydipsia

Because of a decrease in GFR, the tubular fluid in the loop of Henle has been slowed allowing greater reabsorption of sodium and chloride ions in the ascending loop of Henle. The macula densa senses the decrease in sodium concentration. Which one of the following responses occurs?

Afferent and efferent arteriole constriction

Hemoglobin that arises from intravascular lysis of erythrocytes

Will be bound to haptoglobin as long as the lysis is not severe, but if lysis is excessive, haptoglobin becomes saturated and unbound hemoglobin may be filtered and appear in urine, a condition known as hemoglobinuria

Which one of the following nephron parts is associated with the establishment of a high salt concentration in the medulla of the kidney?

Loop of Henle

Loss of solute (Na+ , Cl– ) and retention of water that occurs in the ascending limb of the loop of Henle causes the tubular fluid to be _________ as compared with plasma

Hypotonic

A It is actively transported from the proximal tubule so that about one‐third to one‐half of its presence continues to the loop of Henle

During the process of its being excreted, there is recirculation of some from the inner medullary collecting ducts to the ascending thin limb of the loop of Henle

Which one of the following is associated with diabetes mellitus?

• Increased urine formation

• Renal threshold for glucose is exceeded

• Increased thirst

When antidiuretic hormone from the posterior pituitary is released in greater amounts, what will happen to the fluid in the collecting ducts of the kidney?

It will become more concentrated

Detection of increased osmoconcentration of the ECF by osmorecep- tors in the hypothalamus would result in:

More concentrated urine

Which part of the loop of Henle has the lowest osmolality (greatest dilution)?

Ascending thick limb

Where in the loop of Henle does urea permeability begin and end?

Begins and ends in the thin ascending limb

Movement of solute and water between the vasa recta and the ISF occurs by

Passive diffusion for water, urea, and NaCl

A diuretic that interferes with the cotransport of NaCl in the thick segment of the ascending limb of the loop of Henle would:

Predispose (tendency for) to medullary washout

The renin–angiotensin–aldosterone system is effective in the adjustments needed for the correction of?

Hypovolemia, occurs when your body doesn't have enough fluid (blood) volume

Volume receptors in the left atrium are stretched during hypervolemia that results from increased Na+ intake. Which one of the follow ing is influential in the return to normal?

Inhibition of ERSNA and release of ANP

Extracellular fluid Na+ concentration is regulated by?

Osmoreceptor–ADH system and thirst mechanism

Detection of increased osmoconcentration of the ECF by osmoreceptors in the hypothalamus would by followed by?

Secretion of ADH, more concentrated urine, stimulation of thirst, and water retention

Which one of the following hormones promotes the tubular reabsorption of Na+ and the tubular secretion of K+?

Aldosterone

Tubular fluid is transported from Bowman’s capsule to the renal pelvis by?

Hydrostatic pressure gradient

The most probable reason for the abundant secretion of mucus in the kidney pelvis and upper part of the ureter in the horse is that?

Provides a carrier for the carbonates and phosphates and prevents their collection in the renal pelvis

Creatinine clearance evaluations provide an estimate of?

Functional renal mass

Which division of the autonomic nervous system is associated with micturition?

Parasympathetic

Which one of the following terms most accurately describes a clinical sign of feline urologic syndrome (FUS)?

Stranguria

The usual yellow color of urine is derived from?

Bilirubin

The avian nephron associated with the countercurrent mechanism is the

Mammalian type

Renal portal blood enters the vascular supply perfusing the renal tubules at the level of the

Peritubular capillaries

Ammonia is converted to uric acid in birds?

liver and kidneys

The location for the greatest post‐renal modification of ureteral urine is the

Colon

The salt glands (nasal glands):

Secrete only NaCl and serve an extrarenal osmoregulatory function

Renal portal blood enters the vascular supply perfusing the renal tubules at the level of the

Peritubular capillaries