genitourinary system Flashcards
functions of the kidneys
Regulate body fluid osmolality and volume
Regulate electrolyte balance
Regulate acid-base balance
Excrete metabolic products and foreign substances
Produce and excrete hormones
Gluconeogenic
functional unit of the kidney
the nephron
name some forces that affect ultrafiltration
Hydrostatic pressure PH(blood pressure)
Colloid osmotic pressureπ (due to proteins inplasma but not inBowman’s capsule)
Fluid pressure Pfluid(created by fluid inBowman’s capsule)
describe what is meant by the autoregulation of the glomerular filtration rate
Autoregulation of glomerular filtration rate maintains stable kidney blood flow despite changes in blood pressure, ensuring consistent filtration function.
function of the;
afferent arteriole
efferent arteriole
afferent arteriole brings blood to the glomerulus
the efferent arteriole carries blood away.
ways in which the glomerular filtration rate can be regulated
myogenic response
tubuloglomerular feedback
myogenic response is similar to autoregulation in other systematic arterioles
state some of the ways that Tubuloglomerular feedback affects the GFR
By changing resistancein arterioles(vasoconstriction or vasodilation)
By altering the filtration coefficient
the 3 main components juxtaglomerula apparatus
Macula Densa: A group of specialized cells in the wall of the distal convoluted tubule that monitors the sodium chloride (salt) concentration in the filtrate.
Juxtaglomerular Cells: Specialized smooth muscle cells in the afferent arteriole, near the entrance to the glomerulus. These cells release the enzyme renin in response to signals from the macula densa or changes in blood pressure.
Extraglomerular Mesangial Cells: Cells located between the macula densa and the afferent arteriole, providing structural support.
the two main mechanisms that the JGA is involved in
Tubuloglomerular Feedback
RAAS system
steps involved in the tubuloglomerular feedback
GFR increases
flow through the macula densa increases
flow through the tubules increase
paracrine diffuses from macula densa to afferent arteriole
afferent arteriole constricts
resistance in afferent arteriole increases
hydrostatic pressure in glomerulus decreases
GFR decreases
which component of the nephron reabsorbs the bulk of the filtered solutes and water?
the proximal convoluted tubule
functions of the tight junctions in relation to permeability
Tight junctions form a continuous barrier between adjacent cells, preventing the passage of substances between cells. This barrier function is essential for maintaining tissue integrity and preventing leakage of molecules across cell layers.
In the intestinal epithelium, tight junctions play a key role in regulating the permeability of the epithelial barrier, controlling the selective absorption of nutrients and preventing the entry of harmful substances.
state some of the processes that occur in the proximal convoluted tubule
2/3 of filtrate is reabsorbed
glucose, amino acids and other organic solutesare completely absorbed
Significant amount of phosphate re absorbed
Calcium, water absorbed in parallel with sodium
Active secretion of H+ secretion and resorption of most of filtered bicarbonate
Secretion of organic acids like uric acid anddrugs like penicillin.
importance of bicarbonate absorption in the kidneys
It regulates blood pH by reabsorbing filtered bicarbonate from the renal tubules, preventing excess acidity. This process ensures overall physiological stability and prevents acidosis.
the sodium-hydrogen exchanger
The sodium-hydrogen exchanger (NHE) is a membrane transport protein that plays a crucial role in regulating intracellular pH and sodium homeostasis.
Its primary function is to exchange one intracellular hydrogen ion (H+) for one extracellular sodium ion (Na+).
all molecules that are reabsorbed in the kidney have a maximum transport value(TM), true or false?
not necesarily, but most of them do
note that molecules reabsorbed using transporter proteins oftem have a Tm, because the transporters can get saturated
components of the loop of henle
ascending limb
descending limb
macula densa
note thay we also have the thick and thin ascending limb
in which ascending limb does Ca2+ reabsoprtion happen
in the thick ascending limb
which hormone is related to Ca2+ reabsorption
the PTH
the cortical ascending limb is aka
the medullary ascending limb is aka
the thick ascending limb
the thin ascending limb
Ca2+ reabsorption is regularted by PTH in which ascending limb
thick/ cortical
note that it is not regulated bh PTH in the medullary or thin ascending limb
what happens in the descending limb of the LOH
what happens in the ascending limb of the LOH
primarily facilitates the passive reabsorption of water from the filtrate
active transport mechanisms reabsorb ions, such as sodium and chloride, from the filtrate into the interstitial fluid.
the 2 kinds of nephrons
cortical: Primarily involved in regulating solute concentration and maintaining electrolyte balance. Cortical nephrons have shorter loops of Henle that do not extend deeply into the medulla
juxtamedullary: Play a crucial role in producing concentrated urine. Juxtamedullary nephrons have longer loops of Henle that penetrate into the medulla, allowing for the generation of a significant osmotic gradient.
is the ascending limb permeable to water
no
water reabsorption always follows solute absorption, true or false
false
components of the distal nephron
Distal convoluted tubule and the collecting ducts
Primary site of ADH action
the collecting ducts
difference between a transporter and a symporter
a transporter is a general term for proteins involved in the transport of substances, while a symporter is a specific type of transporter that moves two or more different molecules in the same direction across a membrane. The distinction lies in the specific functional characteristics of symporters, which involve the co-transport of multiple substances.
importance of urea
It helps to maintain the high osmolarity gradient within the medullary region
Important to drive water reabsorption
function of ADH in relation to urea
Allows reabsorption of urea
what happens during urea recycling
Antidiuretic hormone (ADH) stimulates water reabsorption in the collecting ducts, concentrating urea in the tubular fluid. The concentrated urea diffuses back into the interstitial fluid, creating an osmotic gradient that facilitates its reabsorption in the proximal tubule. This reabsorbed urea is then carried in the bloodstream to the kidneys, where it can be excreted again.
osmolality
the concentration of osmotically active particles (solutes) in a solution, measured in osmoles per kilogram of solvent
primary function of the distal convoluted tubule
the fine-tuning of electrolyte balance and the regulation of acid-base balance in the kidney.
It plays a crucial role in the reabsorption of sodium ions and the secretion of potassium and hydrogen ions.
it also affects water reabsorption ofc
stimulation of what part of the brain leads to thirst
the hypothalamus
in the presence of which hormone is the collecting duct permeable to water
vasopressin aka ADH
name at least 2 ways of decreasing water levels in the blod
Increase water excretion
Increase NaCl excretion
functions of the sympathetic nerves in the urinary bladder
Contracts internal urethral sphincter and relaxes detrusor muscle
functions of the parasympathetic nerves in the urinary bladder
Contracts detrusor muscle and relaxes the internal urethral sphincter
this increases intra-bladder pressure, leading to the expulsion of urine
functions of the parasympathetic nerves in the urinary bladder
Under voluntary control
Contracts external urethral sphincter
