Ch. 25- The Urinary System Flashcards
How many liters of blood do the kidneys filter daily?
1/4 of blood; about 200 liters
The kidneys maintain the proper balance between what?
Water, salts, acids and bases
What is produced by the kidneys that help regulate blood pressure?
Renin
What are the four major nitrogenous wastes of the urinary system?
Urea, uric acid, creatinine, ammonia
Creatine phosphate produces…
Creatinine
What is the value of blood urea nitrogen?
6-18 mg/dl
Abnormally elevated BUN
Azotemia
Severe azotemia- diarrhea, vomiting, dyspnea, convulsions, coma, and death
Uremia
In what position are the kidneys found in the abdominal cavity?
Retroperitoneal position
Which kidney is lower and why?
The right kidney is lower because it is crowded by the liver
What helps attach the kidney to the body wall as well as providing cushion for it?
Adipose capsule
What structure anchors the kidney?
Renal fascia
Provides a temporary storage reservoir for urine
Urinary bladder
The light colored, granular superficial region
Cortex
Large branches of the renal pelvis that collect urine draining from papillae and empty urine into the pelvis
Major calyces
Approximately how much of systemic cardiac output flows through the kidneys each minute?
One fourth (1200ml)
What feeds into the peritubular capillaries and vasa recta?
Efferent arteriole
What is the functional unit of the kidney?
The nephron
What are the two parts of a nephron and their function?
Renal corpuscle- blood filtration
Renal tubule- processes filtrate into urine
What is the capillary network of the renal corpuscle?
Glomerulus
Cup-shaped end of a renal tubule that completely surrounds the glomerulus
Glomerular capsule
The glomerulus is a network of what type of capillaries?
Fenestrated
Can proteins pass through the glomerulus?
No
Cells that wrap around the capillaries are called
Podocytes
How many directions of flow are present in the glomerulus?
two; blood and filtrate
Composed of cuboidal cells with microvilli that reabsorbs water and solutes from filtrate and secretes substances into it
Proximal convoluted tubule
Cuboidal cells without microvilli that function more in secretion than reabsorption
Distal convoluted tubule
What two cell types are found in the distal convoluted tubule near the collecting ducts?
Intercalated cells and principal cells
What is the function of intercalated cells?
Maintain the acid-base balance of the body
What is the function of principal cells?
Maintain the body’s water and walt balance
Do intercalated cells have microvilli?
Yes
Do principal cells have microvilli?
No
What are the two types of nephrons?
Cortical nephrons and juxtamedullary
85% of nephrons are what?
Cortical
These nephrons are involved in the production of concentrated urine
Juxtamedullary
How many capillary beds does each nephron have?
2
What are the three major processes of urine formation?
Glomerular filtration, tubular reabsorption and secretion
What is the pressure responsible for filtrate formation?
Net filtration pressure (NFP)
Explain the glomerular filtration forces
55 mmHg of BHP is going out while 30 mmHg of COP is coming in as well as 15 mmHg of CP is coming in
What is the net filtration pressure?
10 mmHG going out
What is the glomerular filtration rate?
125ml/min
What is the equation for GFR?
GFR= NFP x Filtration coefficient
Filtration coefficient equals
12.5 ml/min
What is the glomerular filtration rate?
The volume of filtrate produced by both kidneys per minute
What is the GFR average in men and women?
Men- 125 ml/min
Women- 115 ml/min
What three mechanisms control the GFR?
Renal autoregulation, neural controls, hormonal mechanism
Arteriole walls have _____________ that are enlarged, smooth muscle cells
Juxtaglomerular cells
Have secretory granules containing renin
Juxtaglomerular cells
What system monitors fluid entering DCT and adjusts GFR to maintain homeostasis
Juxtaglomerular apparatus
When do the macula densa cells secrete a vasoconstrictor?
When the GFR is too high
What does sympathetic activity do to the afferent arteriole?
Constricts it
What is released by the sympathetic nervous system?
Norepinephrine
What is released by the adrenal medulla?
Epinephrine
Renin-angiotensin mechanism is stimulated by what nervous system?
Sympathetic
When the JG cells release renin, what is triggered?
The Renin-angiotensin mechanism
