renal system Flashcards
Summarize the functional anatomy of the urinary system
kidneys
- renal cortex/renal medulla: where filtrate is collected and turned into urine
- renal pelvis: collects/ drains the urine produced from the nephrons
- nephron:
- renal capsule: where blood filtrate enters into kidneys
- glomerulus: group of looping fenestrated capillaries
- glomerular capsule: receives filtrate from capillaries
- proximal tubule:
- nephron loop (loop of henle)
- distal tubule
- collecting duct: collect/filtrate and modify before exiting kidneys (urine)
Describe the detailed anatomy of the kidneys and nephrons, including blood flow through the
kidneys
- renal artery
- segmental artery
- interlobar artery
- arcuate artery
- interlobular artery
- afferent artery
- glomerulus
- efferent artery
- peritubular capillaries
- interlobular vein
- arcuate vein
- interlobar vein
- renal vein
Summarize the 3 main processes in urine formation
- glomerular filtration: substances from the blood are filtered into the renal capsule
- tubular reabsorption: filtrate is modified based on the body’s needs
- tubular secretion: more substances are added into the filtrate for excretion as needed
Define glomerular filtration rate and its average value
- amount of filtrate into both kidneys in 1 min (avg: 125ml/min)
Explain how GFR is established by discussing the different pressures involved
- glomerular hydrostatic pressure (GHP): the force of blood against the filtration membrane –> pushes plasma into the capsule
- capsular hydrostatic pressure (CHP): the force of the filtrate pushing against the filtration membrane –> pushes filtrate back into glomerular capillaries
- glomerular colloid osmotic pressure (GCOP): the force created by the presence of proteins in plasma. the protein concentration is higher in the capillary plasma then filtrate –> osmotic P –> pulls water back into capillaries
Explain how GFR can be regulated by myogenic and tubuloglomerular feedback mechanisms
autoregulation
- myogenic mechanisms: the smooth muscles found in the afferent and efferent arterioles vasoconstrict/dilate in response to changes in systemic BP in order to maintain constant GFR
- tubuloglomerular feedback: as GFR increase, volume of filtrate flowing through renal tubule and macula densa cells increase, which releases paracrines that cause vasoconstriction of afferent arteriole and vasodilation of efferent arterioles
Describe the role of each of the following in the control of the GFR: Renin-angiotensin-
aldosterone system, atrial natriuretic peptide, and sympathetic nervous system activity
- RAAS: maintain systemic BP, maintain GFR
- initiated by release of renin from juxtaglomerular cells
- stimulates SNS
- low GHP
- stimulation of macula densa cells - ANP: released by cells in the atria in response of increased BP
- increase GFR –>dilation of afferent arterioles, constriction of efferent arterioles
- increase urine excretion
- decreased BV and BP
Describe the general process of how and where water, organic compounds, and ions are
reabsorbed in the nephron
in the nephron, reabsorption of water, organic compounds, and ions occurs primarily in the renal tubules, specifically in the proximal convoluted tubule (PCT), loop of Henle, distal convoluted tubule (DCT), and collecting ducts
Describe the location(s) in the nephron where tubular secretion occurs
Tubular secretion primarily occurs in the renal tubules of the nephron, specifically in the proximal convoluted tubule (PCT), distal convoluted tubule (DCT), and collecting ducts.
Describe how reabsorption and secretion can be regulated by aldosterone and antidiuretic
hormone
aldosterone and ADH play crucial roles in regulating water and electrolyte balance by modulating reabsorption and secretion in the nephron, thereby helping to maintain blood pressure, blood volume, and electrolyte concentrations within the body.
