GU 19.1 Flashcards
What are the components of the urinary system?
two kidneys
two ureters
one urinary bladder
one urethra
After kidneys filter the blood they return most of the water and many solutes where?
the bloodstream
What is the scientific study of the anatomy, physiology, and disorders of the kidney?
Nephrology
What is the branch of medicine that deals with the male and female urinary system and the male reproductive system?
Urology
What are the 5 functions of the kidneys?
Regulation of ion levels in the blood
Regulation of blood volume and blood pressure
Regulation of blood pH
Production of hormones
Excretion of wastes
What ions are most importantly regulated by the kidneys?
Sodium ions (Na+)
Potassium ions (K+)
Calcium ions (Ca^2+)
Chloride ions (Cl-)
Phosphate ions (HPO4^2)
How do the kidneys adjust blood volume?
returning water to the blood or eliminating it in the urine
Blood pressure is regulated by what?
Secreation of enzyme renin
Enzyme renin does what?
activates the renin-angiotensin-aldosterone pathway by adjusting blood flow into and out of the kidneys, and by adjusting blood volume
How do the kidneys regulate the concentration of H+ in the body?
Excreting a variable amount of H+ in the urine
The kidneys conserve what important buffer of H+ to regulate pH?
HCO3-
What hormones do the kidneys produce?
Calcitriol
Erythropoietin
Calcitriol is the active form of vitamin D and does what?
Helps regulate calcium homeostasis
What does erythropoietin do?
stimulates production of red blood cells
What wastes or substances do the kidneys excrete?
Ammonia and urea
Bilirubin
Creatinine
Uric acid
Drugs and enviromental toxins
Ammonia and urea are from the breakdown of what?
Amino acids
Bilirubin is from the breakdown of what?
hemoglobin
Creatinine is the breakdown from what?
Creatine phospate in muscle fibers
Uric acid is the breakdown from what?
nucleic acids
Where do kidneys lie in the body?
Either side of the vertebral column between the peritoneum and the back wall of the abdominal cavity
between T-12 and L-3
What provides protection for the superior aspect of the kidneys?
11-12th pairs of ribs
What is the indentation near the center of the medial border of the kidney called?
Renal hilum
What enters and exits at the renal hilum?
Enters/Exit
-blood vessels
-lymphatic vessels
-nerves
Exit
-Ureters
What surrounds each kidney that is smooth, transparent, connective tissue sheath that gives shape and serves as a barrier against trauma?
renal capsule
What surrounds the renal capsule and cushions the kidney as well as anchors the kidney to the posterior abdominal wall with dense irregular connective tissue?
Adipose tissue
What are the two main regions inside the kidney?
Renal cortex
Renal medulla
Which region of the internal kidney is the outer light-red region?
Renal cortex
Which region of the internal kidney is the inner, darker red-brown region?
Renal medulla
Cone-shaped renal pyramids are within what structures?
Renal medulla
What structures fill the spaces between renal pyramids and are extensions of the renal cortex?
Renal columns
What cuplike structures does urine that is formed in the kidney pass from papillary ducts into?
minor calyces
How many minor calyces are in each kidney?
8-12
Urines flows from the minor calyces to what?
Major calyces
How many major calyces are in a kidney?
2-3
Urine travels from the major calyces to the single large cavity called?
renal pelvis
The renal pelvis drains urine into the ureter that transports urine to where? and then where?
urinary bladder
urethra
How much of the resting cardiac output flows into the kidneys through the right and left renal arteries?
20-25%
1200 mL of blood per min
What smaller vessels do renal artery divide into? (all)
segmental
interlobar
arcuate
Cortical radiate
Vessels that branch from the renal artery ultimately deliver blood to what structure?
afferent arterioles
afferent arteriole divide into a tangled capillary network called the?
glomerulus
The capillaries of the glomerulus reunite to form what structure?
Efferent arteriole
What capillaries do efferent arterioles divide into?
peritubular capillaries
Where do the veins from the peritubular capillaries ultimately drain into after leaving the glomerulus?
Renal vein
What is the functional unit of the kidney?
Nephron
How many nephrons are in each kidney?
About a million
What are the two parts of the nephron?
Renal corpuscle
Renal tubule
Where is blood plasma filtered in the nephron?
Renal corpuscle
Filtered fluid, called glomerular filtrate passes through what structure of the nephron?
Renal tubule
What is added to fluid as it moves through the renal tubles?
Waste
excessive substances
What are the two parts that make up a renal corpuscle?
glomerulus
glomerular capsule (Bowman’s)
Glomerular filtrate enters the glomerular capsule and then pass into the?
renal tubule
What are the three main sections of the renal tubule?
proximal convoluted tubule
loop of Henle
distal convoluted tubule
What lies within the renal cortex?
Renal corpuscle
Convoluted tubules
What structure of the renal tubule extends into the renal medulla?
loop of Henle
What does a papillary duct lead into?
minor calyx
major calyx
renal pelvis
ureter
What are the basic functions performed by a nephron?
Glomerular filtration
tubular reabsorption
tubular secretion
What is the first step of urine production?
Glomerular filtration
What forces water and blood plasma solutes across the glomerular capillaries?
Blood pressure
How much of the filtered water and useful solutes to the blood during tubular reabsorption?
99%
The filtered fluid is called urine after tubular reabsorption and secretion and it enters what structures?
minor and major calyx
Nephrons perform glomerular filtration, tubular reabsorption and tubular secretion to maintain what?
Homeostasis of blood volume and composition
What two layers of cells compose the capsule that surrounds the glomerular capillaries?
podocytes
simple squamous epithelial cells
Why do blood cells and most plasma proteins remain in the blood during filtration?
Too large to pass through membrane
What are two pressures that oppose glomerular filtration?
Blood colloid osmotic pressure
Glomerular capsule pressure
When osmotic or capsule pressure increases what happens to glomerular filtration?
decreases
What is the normal net filtration pressure when blood pressure is greater than osmotic and capsule pressures?
10 mm Hg
How much volume does net filtration pressure force into the capsular space for men and women?
M- 180 L
F- 150 L
What is the formula for net filtration pressure?
Blood colloid osmotic pressure + Glomerular capsular pressure
minus
Glomerular capillary blood pressure
equals
Net Filtration pressure
Which arteriole assists with raising blood pressure and has a smaller diameter?
Efferent
The amount of filtrate that travels through the kidneys every minute is called?
Glomerular filtration rate
What is the GFR for men and women?
M- 125mL/min
F- 105mL/min
What happens to substances if the GFR is too high?
pass out of the body in urine due to inability to reabsorb
What would cause all filtrate being reabsorbed and waste not be excreted in the urine?
Low GFR
What hormone promotes loss of sodium ions and water in urine partly due to increase glomerular filtration rate and involves the stretching of the atria?
Atrial Natriuretic Peptide (ANP)
ANP acts on what organ to increase loss of sodium ions and water in urine to reduce blood volume?
Kidneys
What would be seen when vessels are constricted, i.e. exercise or hemorrhage, in the kidneys?
blood flow to glomerular capillaries is decreased
NFP drops
GFR drops
What is the second basic function of nephrons and collecting ducts?
Tubular reabsorption
What percentage of water in glomerular filtrate leaves the body in urine?
1%
Where does the 1% of the water in filtrate leave the kidney?
Renal pelvis
What makes up the largest contribution to reabsorption?
Proximal convoluted tubules
What does the PCT reabsorb?
65% of filtered water
100% of filtered glucose and amino acids
large quants of ions (Na+, K+, Cl-, HCO3-, Ca^2+ & Mg^2+)
Water moves by what into peritubular capillaries?
osmosis
What is the third function of the nephrons?
tubular secretion
What is tubular secretion?
the transfer of materials from the blood through tubule cells into tubular fluid
Tubular absorptions occurs via what?
passive diffusion
active transport processes
What secreted substances are seen in the tubular secretion phase?
Hydrogen ions (H+)
Potassium (K+)
ammonia (NH3)
urea
creatinine
drugs (PCN)
What basic function of the nephrons helps eliminate substances from the body?
Tubular secretion
Urea and ammonia are secreted in sweat but mostly where?
Urine
What does tubular secretion help control?
blood pH
Urine is typically acidic due to what ion being secreted?
H+
What is the pH of urine?
Below 7
What are the most important hormonal regulators of ion reabsorption in the nephrons?
angiotensin II
aldosterone
Angiotensin II enhances what to take place in the PCT?
Na+ and Cl- reabsorption
Angiotensin II stimulates what to release aldosterone?
adrenal cortex
Aldosterone stimulates the DCT to do what?
Reabsorb more Na+ and Cl-
Secrete K+
What occurs when more Na+ and Cl- are absorbed?
More water is retained by osmosis
What is the major regulator of K+ in the blood?
Aldosterone-stimulated secretion
What plays a small role in the inhibition of Na+ and Cl- reabsorption and increases glomerular filtration rate?
ANP
What is the major hormone that regulates water reabsorption?
Antidiuretic hormone (ADH)
ADH operates via what?
Negative feedback
What stimulates ADH to be released from the posterior pituitary?
Water concentration in blood decreases by 1%
Hemorrhage
Severe dehydration
In the absence of ADH, renal tubes have what?
very low permeability
Water permeability of tubules is achieved when ADH causes what?
insertion of proteins to form channels in the plasma membrane
Low levels of Ca^2+ in the blood stimulates the parathyroid gland to release what?
Parathyroid hormone (PTH)
What part of the tubules does PTH act on to reabsorb more Ca^2+?
DCT
PTH also inhibits what ion reabsorption in the PCT promoting it’s excretion?
HPO4^2- or phosphate
What is the normal volume of urine eliminated per day in a normal adult?
1-2 L
Water accounts for what percentage of total volume of urine?
95%
What solutes are typically present in urine? (long list…11 things)
urea
creatinine
potassium
ammonia
uric acid
sodium
chloride
magnesium
sulfate
phosphate
calcium`
What structures transport, store and eliminate urine?
Ureters
Urinary Bladder
Urethra
Ureters transport urine from what structure to the bladder?
Renal pelvis
What compresses the ureters to prevent backflow?
Bladder
What illness may arise if the urinary bladder physiological valve of the ureters is not functioning properly?
cystitis to kidney infection
The wall of the ureter consists of what layers?
Mucosa
Middle layer of smooth
outer layer of areolar connective tissue
What does the mucosa contain what allows the ureter to stretch to accommodate variable volume of fluid?
transitional epithelium
How do ureters transport urine from the renal pelvis to the bladder?
peristaltic contractions
What layer of the ureter houses the nerves, blood and lymph vessels?
outer layer
Where does the bladder sit in the pelvic cavity?
behind the pubic symphysis
infront of the rectum (male)
infront of the vagina, below uterus (female)
The shape of the bladder is determined by what?
the amount of urine it contains
What is the average capacity of urine held in the bladder?
700-800ml
What is the muscular layer or the bladder wall called?
detrusor muscle
What are the layers of the bladder?
Mucosa
detrusor muscle
peritoneum
Which urethral sphincter is composed of skeletal muscle and is under voluntary control?
External urethral sphincter
Urination is also known as what?
micturition
Stretch receptors are activated in the bladder when the pressure exceeds from urine volume above what?
200-400 ml
Where do bladder stretch receptors transmit nerve impulses to?
spinal cord
What is the reflux that occurs when the bladder stretch receptors are activated?
micturition reflex
Parasympathetic impulses from the spinal cord during post micturition reflex causes detrusor muscles and internal urethral sphincter muscle to do what?
Detrusor - contract
Internal sphincter - relax
What is inhibited to cause relaxation of skeletal muscles in the external urethral spinchter?
somatic motor neurons
Body fluids make up what percentages of total body mass in a lean adult?
55-60%
Fluids in the body are present in what two main compartments?
inside and outside cells
What amount of fluid in the body are found within cells?
two-thirds
Fluids found in the cells are called what?
intracellular fluid or cytosol
Fluid outside the cells are called what?
Extracellular fluids
How much fluid in the body is found outside the cells?
one-third
What is the breakdown of fluids in extracellular fluid?
80% interstitial fluid
20% blood plasma
What are other examples of extracellular fluids that are grouped with interstitial fluid?
Lymph
Cerebrospinal
Synovial
aqueous humor and vitreous
endolymph and perilymph
pleural, pericardial and peritoneal
What are the two barriers that separate intracellular fluid, interstitial fluid and blood plasma?
Plasma membrane
Blood vessel walls
Which barrier separates intracellular fluid from the surrounding interstitial fluid?
plasma membrane
Water is the largest single component of the body, making up what percentage of total body mass?
45-75%
Movement of water between intracellular and interstitial fluid is determined by what?
concentration of solutes
What is the utmost importance of the kidneys in the maintenance of homeostasis?
The ability of the kidneys to excrete dilute urine or concentrated urine
What are the two methods body can gain water?
Ingestion
Metabolic reactions
About how much liquid is from ingested liquids?
1600 ml
What amount of water is gained by moist food?
about 700 ml
What is the total amount of water absorbed in the GI tract a day?
2300 ml
Metabolic water gains is usually what amount?
200 ml/day
Daily water gain totals what amount?
2500ml
Excretion values are:
Kidneys-
Evaporation-
Exhale-
Feces-
Kidneys- 1500ml
Evaporation- 600ml
Exhale- 300ml
Feces- 100ml
What area is known as the thirst center?
hypothalamus
What amount of fluid must decrease for mild dehydration to exist?
2% of fluid loss
What are the two main solutes in extracellular fluids?
Sodium ions (Na+)
Chloride ions (Cl-)
What are the three hormones that regulate the extent of renal Na+ and Cl- reabsorption?
Atrial natriuretic peptide
Angiotensin II
Aldosterone
What does atrial natriuretic peptide promote?
natriuresis (secretion of salt)
When blood volume increases renin is released more slowly effecting what hormone?
angiotensin II
What is the major hormone that regulates water loss?
antidiuretic hormone (ADH)
When intracellular and interstitial fluids are the same cells do what?
neither shrink nor swell
Cells shrink slightly when what is occuring?
increase osmotic pressure in interstitial fluid
A decrease in the osmotic pressure of interstitial fluids causes cells to do what?
swell
What is the most abundant extracellular ion?
Sodium ions (90% of extracellular cations)
What is the most prevalent anions in extracellular fluid?
Chloride ions
What is the most abundant cation in intracellular fluid?
Potassium
What is exchanged when K+ moves in or out of a cell?
H+
The level of K+ in blood plasma is controlled by what hormone?
Aldosterone
98% of calcium is located where in adults?
Skeleton and teeth
What are the main regulators of Ca^2+ in the blood plasma?
Parathyroid hormone (PTH)
calcitriol
What are the functions of electrolytes?
Control the osmosis of water between fluid compartments
Maintain acid-base balance
Carry electrical current
Serve as cofactors
How are ions formed?
when electrolytes break apart
What is the chief difference between the extracellular fluids?
blood plasma contains many protein anions
interstitial fluids has very few
What is the major homeostatic challenge to keep pH in range?
maintaining appropriate H+ ions
North American diets generally do what to blood pH?
acidify the blood
What are the three major mechanisms to remove H+ from the body?
buffer systems
exhalation of CO2
kidney excretion into urine
What are the three buffer systems?
Protein
Carbonic Acid-Bicarbonate
Phosphate
What is the most abundant buffer in intracellular fluid and plasma?
Protein buffer system
What are the functional groups of the protein buffer system?
carboxyl group
amino group
Carboxyl groups does what when pH rises?
releases H+
What group in the protein buffer system combines with H+ when pH fails?
Amino
The protein buffer system can act on acids or bases?
both
The carbonic acid-bicarbonate buffer system can act as what?
a weak base (bicarb)
a weak acid (carbonic)
What are the components of the phosphate buffer system?
dihydrogen phosphate
mono-hydrogen phosphate
Which component of the phosphate buffer system can act as a weak acid?
dihydrogen phosphate ion
Which component of the phosphate buffer system can act as a weak base?
mono-hydrogen phosphate
Phosphate buffer system is an important regulator of pH in what?
cytosol
An increase in CO2 in body does what to H+ concentration?
increases H+
An increase in H+ in the blood makes the pH?
more acidic
A decrease in CO2 in body fluids raises the pH making it what?
more alkaline
Increased ventilation can cause what to happen IRT blood pH?
CO2 decreases
H+ falls
pH rises
If ventilation is slower or decreased what happens to blood pH?
Falls
What can stimulate the inspiratory area in the medulla oblongata?
chemoreceptors
Where are the chemoreceptors that stimulate the inspiratory area?
medulla oblongata
aortic body
carotid body
What is the slowest mechanism of removing acids?
Kidney excretion of H+
Kidneys synthesize and reabsorb what important buffer in the urine that contributes to the acid-base balance?
HCO3-
What is the condition when arterial blood pH is below 7.35?
Acidosis
What is the principal physiological effect of acidosis?
depression of the CNS, synaptic transmission
coma or death may occur if the pH falls below what?
7
What is the condition where blood pH is higher than 7.45?
alkalosis
What is the major physiological effect of alkalosis?
over-excitability of the CNS and peripheral nerves
What is the term for hypo or hyperventilation that can return blood pH to normal?
respiratory compensation
What is the compensation that occurs if the blood pH change is due to respiratory causes?
renal compensation
How quickly does respiratory compensation occur and reach its maximum effectiveness?
occurs within minutes
maximum effect in hours
How quickly does renal compensation occur and reach its maximum effectiveness?
occurs within minutes
takes days to reach max effect
