The Urinary System Flashcards
List the 6 components of the urinary system
- 2 Kidneys
- 2 Ureters
- 1 Urinary Bladder
- 1 Urethra
What are the 2 combining words forms for kidney?
- Nephro-
- Reno-
In what 5 ways does the kidney help maintain homeostasis?
- Blood filtration, reabsorption, and secretion
- Fluid balance regulation
- Acid-base balance regulation
- Hormone production
- Blood pressure regulation
What are the 2 major functions of the kidneys?
- Urine production > waste removal
- Manipulating blood plasma > help maintain homeostasis
The amount of urine produced relies on what?
Amount of water in the body
Which 2 hormones control the amount of water in urine?
- Antidiuretic Hormone (ADH)
- Aldosterone
the overproduction of urine due to excess water in the body
Diuresis
the production of small amounts of urine when the body needs to conserve water
Oliguria
the lack of urine production when the body severely needs to conserve water
Anuria
What do the kidneys remove from the blood to maintain proper blood pH?
- Acidic hydrogen ions
- Alkaline bicarbonate ions
the thick layer of fat surrounding the kidneys to protect them from pressure exerted by surrounding organs
Perirenal Fat
Kidneys are located ________ to the abdominal cavity
Retroperitoneal
Explain how the kidneys are retroperitoneal to the abdominal cavity
Outside the parietal peritoneum
Between peritoneum + dorsal abdominal muscles
the indented area on the medial side of the kidney where blood and lymph vessels, nerves, and the ureters enter and leave the kidney
Hilus
a funnel-shaped, elastic urine collection chamber inside the hilus that forms the beginning of the ureter
Renal Pelvis
the reddish brown, granular-looking outer portion of the kidney
Renal Cortex
the smooth, inner portion of the kidney around the renal pelvis that has a dark purple outer area and a pale, gray-red inner area
Renal Medulla
a kidney structure characterized by a scalloped-shaped medulla, made of numerous pyramid-shaped areas with the apex pointing to the renal pelvis or directly to the ureter, and a cortex that fills in around the scallops
Multipyramidal (Multilobar)
a kidney structure characterized by fused medullary pyramids that occupy the entire inner area and a cortex that is pushed to the outside area only
Unipyramidal (Unilobar)
Which species have multilobar vs unilobar kidney structures?
- Multilobar - cattle and pigs
- Unilobar - dogs, horses, cats
the basic functional unit of the kidney
Nephron
funnel-shaped extensions that direct urine into the renal pelvis so it can move into the ureter
Calyx (pl. Calyces)
of nephrons per kidney varies by what?
Size of the animal
List the 4 components of a nephron
- Renal corpuscle
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
a tuft of glomerular capillaries in the renal corpuscle
Glomerulus
a double-walled capsule that surrounds the glomerulus of the renal corpuscle
Bowman’s Capsule
inner layer of the Bowman’s capsule made of podocytes that adheres to the surfaces of all glomerular capillaries
Visceral Layer
the outer layer of the Bowman’s capsule
Parietal Layer
the region between the visceral and parietal layers of the Bowman’s capsule and is continuous with the proximal convoluted tubule
Capsular Space
the fluid that is filtered out of blood by the renal corpuscle
Glomerular Filtrate
The structure that filters blood in the first stage of urine production
Renal Corpuscle
the filtered fluid after it leaves the renal corpuscle
Tubular Filtrate
structures that carry tubular filtrate through the medulla into the calyces and play an important role in urine volume, potassium regulation, and acid-base balance control
Collecting Ducts
Which nervous system causes vasoconstriction of renal vessels to temporarily decrease urine function?
Sympathetic Nervous System
the blood vessels of the kidney that branch off the abdominal aorta and enter the kidney at the hilus
Renal Arteries
the blood vessels of the kidney that carry blood into the glomerular capillaries of the renal corpuscle
Afferent Glomerular Arterioles
the blood vessels of the kidney that link the afferent and efferent glomerular arterioles and is the only place in the body where blood entering and leaving the capillaries is oxygenated blood
Glomerular Capillaries
the blood vessels of the kidney that divide into a network of capillaries that surround the rest of the nephron
Efferent Glomerular Arterioles
the blood vessels of the kidney that surround the nephron coverage to form venules
Peritubular Capillaries
the blood vessels that leave the kidney at the hilus and joins the abdominal portion of the caudal vena cava and hold the purest blood in the body
Renal Veins
What can be an indicator of glomerular damage?
Abnormal amounts of protein in urine
term used to describe how fast plasma is filtered as it passes through the glomerulus
Glomerular Filtration Rate (GFR)
What is glomerular filtration rate expressed as?
Milliliters per minute
Glomerular Filtration Rate depends on _______
the rate of blood flow to the kidneys
the process by which sodium in the tubular filtrate attaches to a carrier protein that actively carries it into the PCT epithelial cell, while at the same time glucose and amino acids attach to the same protein and passively follow the sodium into the cell
Sodium Cotransport
the elimination of the remaining waste products and foreign substances not filtered from the blood by transferring them from peritubular capillaries to the interstitial fluid, the tubular epithelial cells, and into the tubular filtrate
Tubular Secretion
Urine volume regulation is determined by ________
the amount of water contained in the tubular filtrate when it reaches the renal pelvis
What organ secretes ADH?
Posterior pituitary gland
What organ secretes aldosterone?
Adrenal cortex
How does ADH influence urine volume regulation?
Promotes water reabsorption
How does a lack of ADH influence the urinary system?
No ADH > water not reabsorbed > water lost in urine > polyuria
How does aldosterone influence urine volume regulation?
Promotes sodium reabsorption
How does sodium reabsorption via aldosterone influence urine volume regulaton?
Increased sodium reabsorption > osmotic imbalance > water wants to follow sodium out of tubular filtrate > into blood
a tube that exits the kidney at the hilus and connects to the urinary bladder near the neck of the bladder at its caudal end
Ureter
the arrangement of the 2 openings from the ureters into the bladder and the opening from the bladder into the urethra
Trigone of the Bladder
What type of epithelium lines the inner layer of the ureters? Why?
Transitional Epithelium > allows it to stretch
Where does each ureter leave its kidney?
At the hilus
Why is the smooth muscle in the middle layer of the ureters important?
Peristaltic contractions > propels urine through ureters > urine moves to bladder regardless of body position
List the 2 components of the urinary bladder
- Muscular sac
- Neck
bundles of smooth muscle in the wall of the urinary bladder function to expel urine from the urinary bladder
Detrusor Muscle
Which part of the urinary bladder is under voluntary control?
Circular sphincter muscle in the neck of the bladder
the expulsion of urine from the urinary bladder into the urethra for elimination from the body
Urination
Micturition
Urination
Uresis
Urination
What are the 3 steps to urination?
- Urine Accumulation
- Muscle Contraction
- Sphincter Muscle Control
Explain the differences between the urethras of male and female animals
Females
- short and straight
- opens on ventral portion of the vestibule of the vulva
Males
- long and curved
- runs along ventral aspect of the penis
The ureters of (females/males) have both urinary and reproductive functions
Males
the laboratory evaluation of a urine sample
Urinalysis (UA)
What are some conditions a UA can help identify?
- Infections
- Crystalluria
- Urinary calculi
- Diabetes mellitus
List the 3 steps to complete a UA
- Gross examination of the physical properties of the sample
- Chemical analysis of substances dissolved in the urine
- Microscopic examination of the sediment in the urine
What 5 physical properties do you examine for a UA?
- Volume
- Color
- Odor
- Transparency
- Specific Gravity (SG)
a reflection of the concentration of the urine that is measured using a refractometer
Specific Gravity (SG)
What 7 things are you looking for in the chemical analysis of a UA?
- Urine pH
Presence of: - Protein
- Glucose
- Ketones
- Bile pigments - bilirubin and urobilinogen
- RBCs
- WBCs
What 6 types of sediment are you looking for in the microscopic examination of a UA?
Presence of:
1. RBCs
2. WBCs
3. Epithelial Cells
4. Tubular cells
5. Crystals
6. Microorganisms - bacteria, fungi, parasites
What are the 2 methods of UA sample collection?
- Catheterization
- Cystocentesis
How do you perform a cystocentesis?
- Needle inserted through skin of lower abdomen > into the bladder
- Urine is drawn directly from the bladder through needle > into sterile syringe
a series of pads that are each impregnated with a chemical that causes a color change to indicate the presence of a particular substance in the urine
Reagent Strips
What is used to perform the chemical analysis of a UA?
Reagent strips
How do you perform the microscopic examination of sediment in a UA?
- Urine placed in a test tube > centrifuged > concentrates sediment into a pellet at bottom of tube
- Sediment examined microscopically
the limited amount of glucose that can be reabsorbed by the proximal convoluted tubules
Renal Threshold of Glucose
What is the renal threshold of glucose for dogs vs cats?
Dogs ~180 mg/dl
Cats ~240 mg/dl
What happens if blood glucose levels exceed renal threshold?
Excess lost in urine
the presence of glucose in the urine
Glycosuria
abnormally high urine volume production which results in frequent urination
Polyuria
a condition where certain substances in the kidneys prevent water from being reabsorbed and results in polyuria
Osmotic Diuresis
increased and excessive thirst
Polydipsia
Give the 2 classifications of renal failure
- Acute
- Chronic
Renal failure due to sudden necrosis of the renal tubules via toxicity or decreased renal perfusion
Acute Renal Failure
What is the critical point for chronic renal failure?
Destruction of 2/3 of the nephrons in the kidneys
Give 5 clinical signs of chronic renal failure
- Proteinuria
- Dilute urine
- Uremia
- Azotemia
- Nausea/Vomiting
the presence of protein in the urine and is one of the earliest signs of chronic renal failure
Proteinuria
the abnormal buildup of urea in the blood
Uremia
the abnormal buildup of creatinine in the blood
Azotemia
What causes the nausea and vomiting in chronic renal failure?
The uremia and azotemia
What is the treatment for chronic renal failure?
- Treat clinical signs > improve quality of life
- Fluid therapy
- Low protein + mineral diet
a disease characterized by a water imbalance, polyuria and compensatory polydipsia due either to (1) inadequate ADH levels and thus causing the collecting duct to reabsorb inadequate amounts of water or (2) the collecting ducts being unable to respond to the presence of adequate amounts of ADH
Diabetes Insipidus
term for any pathologic condition that results in inability of the urinary system to remove waste materials adequately from the blood
Renal Dysfunction
the presence of urea in the blood
Uremia
What are the 3 types of uremia?
- Prerenal Uremia
- Renal Uremia
- Postrenal Uremia
the condition in which the kidneys are functioning normally but the blood flow to them has decreased, which results in the inadequate removal of waste materials
Prerenal Uremia
the condition in which there is adequate blood flow to the kidneys but they are unable to regulate urine production adequately due to a decrease in functional nephrons, which results in waste materials unable to be removed from the blood
Renal Uremia
the condition in which there is adequate blood flow to the kidneys and a normal amount of functioning nephrons, but there is an obstruction preventing urine from being expelled from the body
Postrenal Uremia
How do you diagnose uremia?
Evaluate BUN levels in blood sample
What does BUN stand for?
Blood urea nitrogen
aggregate of calculus in the urinary tract
Urolith
What are 2 other names for uroliths?
- Urinary Stones
- Urinary Calculi
What are the most common types of uroliths in dogs?
Struvite
What are the most common types of uroliths in ruminants?
- Struvite
- Calcium Carbonate
- Calcium Oxalate
the condition in which urinary stones are present anywhere in the urinary system
Urolithiasis
inflammation of the bladder
Cystitis
inflammation of the urethra
Urethritis
What makes feline uroliths different from other species?
Much smaller and resemble sand instead of large stones
What are the most common types of uroliths in cats?
- Struvite
- Calcium oxalate
