Chapter 23 Flashcards
Organs of the urinary system
Kidneys ureters urinary bladder urethra
8 roles of the urinary system
Filter blood plasma excrete toxic metabolic waste
Regulate blood volume pressure regulating water output
Regulate electrolyte and acid-base balance
Secrete hormones supports oxygen carrying capacity of blood
Regulate calcium homeostasis and bone metabolism
Clear hormones and drugs from the blood
Detoxify free radicals
Support blood glucose levels
Waste
Substance useless to the body
Metabolic waste
Waste substance produced by the body
Nitrogenous waste
Metabolic waste small nitrogen containing compound
Blood urea nitrogen
Level of nitrogenous waste in the blood
3 Nitrogen wastes
Urea uric acid creatine
What does the respiratory system excrete
Carbon dioxide gases and water
What does the integumentary system excrete
Water in organic salts lactic acid and urea
What does the digestive system secrete
Food residue water salts CO2 lipids bile pigments cholesterol metabolic waste
What does the urinary system excrete
Metabolic waste toxins drugs hormones salts hydrogen ions water
Flow of fluid from Glomerular filtrate to when Urine leaves body
Descending limb nephron loop ascending limb distal con voluted tube collecting duct papillary duct minor calyx major Calyx renal pelvis ureter urinary bladder urethra
Cortical nephrons
Close to kidney surface short neohron loops
Juxtamedullary nephrons
Close to medulla very long nephron loop
Renal innervation
Reduce glomerular blood flow and urine production
Respond to calling blood pressure stimulates kidneys to produce renin
Glomerular filtrate
Fluid in capsular space similar to blood plasma except has no protein
Tubular fluid
Fluid from proximal convoluted tubule her through the distal convoluted tubule
Urine
Fluid once it enters the collecting duct
Glomerular filtration
Water and some solutes in the blood plasma pass through capillaries into the capsular space of the nephron
Three barriers of the filtration membrane
Fenestrated endothelium of capillary highly permeable
Basement membrane excludes large molecules
Filtration slits obstacle arms with slits which are obstacles to large anions
What substance is not present in glomerular filtrate
Similar to blood plasma except it has no proteins
Net filtration pressure
High outward pressure of 62 in word pressures of 18 and 32
Glomerular filtration rate
Amount of filtrate formed per minute by two kidneys
GFR too high
Fluid flows through renal tubule’s to rapidly for them to reabsorb the normal amount of water and solutes urine increases dehydration
GFR to low
Fluid flow slowly through tubules reabsorb waste that should’ve been illuminated
Renal autoregulation
Mechanism to change glomerular blood pressure
Ability of the nephrons to adjust to their own blood flow and a GFR without external control nervous or hormonal
Myogenic mechanism
Tendency of smooth muscle to contract when stretched
BP rises stretches afferent arteriole
Arteriole constricts and prevents blood flow
Tubuloglomerular feed
Adenosine cells constrict afferent arterial Reduces blood flow reduce his GFR completing negative feedback loop
Muscula densa
Absorb na k and cl swell secrete ATP from their basal surfaces
Mesangial cells
ATP is metabolized to adenosine and pack the spaces between the arterioles and within the glomerulus
Granular cells
Respond to rising adenosine level by constructing the afferent arteriole reduces blood flow reduce GFR
What stimulates the production of renin
Drop in blood pressure
What blood plasma protein does renin act on
Angiotensin aldosterone
What is this blood plasma protein converted to
Angiotensin II hormone that acts in several ways to restore fluid volume and blood pressure
What enzyme produced by the lungs and kidneys acts on angiotensin II
Angiotensin converting enzyme
Six actions of angiotensin II
Vasoconstrictor raises mean arterial blood pressure
Raises glomerular blood pressure and GFR ensuring filtration of waste from blood
Lower blood pressure more water is returned to the bloodstream instead of being lost in the urine
Stimulates adrenal cortex to secrete aldosterone sodium and water reabsorption
Pituitary gland to secrete antidiuretic hormone which promotes water reabsorption
Stimulates sense of thirst and encourages water intake
Tubular reabsorption
Reclaiming water and solutes from the tubular fluid and returning them to the blood
Why is sodium reabsorption in the PCT important
It creates an osmotic and electrical gradient that drives the reabsorption of water and other solutes
Four primary substances that are reabsorbed in the PCT
Electrolytes glucose water nitrogenous waste
Obligatory water reabsorption
In PCT when water is reabsorbed at a constant rate
Transport maximum
Maximum rate of reabsorption reached when transporters are saturated
Four primary substances absorbed in the nephron loop
Sodium potassium chloride water
Two primary substances reabsorbed in the DCT and collecting duct
Water salts
What is the function of principal cells
Salt and water balance
Function of intercalated cells
Reabsorb K and secrete H into tubule and are mainly in acid-base balance
Aldosterone
Water retention helps maintain blood volume and pressure
Natriuretic peptides
Reduce blood volume and pressure
Antidiuretic hormone
ADH makes collecting duct more permeable to water
Parathyroid hormone
Helps minimize further decline in blood calcium levels
Tubular secretion
Renal tubule extracts chemicals from capillary blood and secretes them into the tubular fluid
Three purposes of tubular secretion
Acid-base balance by hydrogen and bicarbonate ions
Extracts waste from the blood
Clears drugs and containments from the blood
Water diuresis
If you drink a large volume of water produce large volume of hypo tonic urine
Response to dehydration in the collecting duct
Transfer aquaporins from storage vesicles in cytoplasm to apical cell surface cells take water from tubular fluid if ADH remains high for 24 hours manufacture more aquaPorins
Countercurrent exchange system
The vasa recta from carrying the urea and salt needed to maintain high osmolarity of the medulla
What does the collecting ducts ability to concentrate urine depend on
Osmotic gradient
How does a nephron loop act as a counter current multiplier
Continually recapture salt and returns it to the deep medullary tissue
Multiplier
Multiplies osmolarity deep in the medulla
Countercurrent
Fluid flowing in opposite directions in two adjacent tubules
Descending limbs
Very permeable to water but not sodium chloride water passes by osmosis into ECF leaving NaCl behind
Ascending limbs
Impermeable to water pumps that transport sodium potassium and chloride into the ECF
Four components of involuntary micturition reflex
Stretch receptors detect filling of bladder transmit afferent signals to spinal cord
Signals return to bladder from spinal cord via parasympathetic fibers in pelvic nerve
Efferent signals excite detrusor muscle
Efferent signals relax internal urethral Sphinter urinary is involuntarily voided if not inhibited by brain
