Ch 23: Urinary System Flashcards
What are the 7 functions of the urinary system?
- Excretion of cellular waste
- Regulation of water balance
- Regulation of electrolytes
- Secretion of erythropoietin
- Regulation of produces calcitriol (for bone remodeling)
- Clears hormones and drugs from blood stream
- Detoxifies free radicals
The urinary system’s regulation of water balance maintains…
blod volume/pressure
A high amount of hydrogen in blood results in a _____ blood pH, which indicates the blood is more _____.
higher, acidic
What electrolytes are action potentials?
- sodium
- chloride
- potssium
- calcium
What electrolytes effect osmolarity?
- sodium
- chloride
What electrolytes effect blood pH?
- hyrdrogen
- bicarbonate
Erythropoietin is responsible for…
the production of RBCs
Calcitrol is used for
bone remodeling/homeostasis
Starvation can produce…
glucose from amino acids
What are the four parts of that make up the gross anatomy of the urinary system?
Give the characteristics of each.
- Kidneys: main organ, produce urine
- Ureters: tubes leading from kidneys to bladder
- Urinary bladder: stores urine
- Urethra: pee tube, path of exit
Kidneys are located in the _____ area of the _____ cavity.
posterior/dorsal, abdominopelvic
The pertoneum is the…
serous membrane lining the cavity of the abdomen and covering the abdominal organs.
True or False
The kidneys are inside the perotoneum.
False
What is meant by the kidneys are retroperotoneal?
That they sit behind and outside the perotoneum.
What are the three membrane layers that surround the kidneys?
Give characteristics of each.
- Renal fascia: dense connective tissue holding kidneys in place
- Perineal fat capsule: protects kidneys
- Fibrous capsule: thin, transparent membrane that protects against infection
What are the four main parts that make up the internal kidney’s gross anatomy?
- Cortex: contains nephrons
- Medulla: contains pyramidal tubules and nephron loops
- Renal Pelvis: formed from the convergence of minor calyx and major calyx
- Hilus: indentation in the surface of a kidney, where blood vessels, ducts, nerve fibers, etc. enter or leave it.
What function do the nephrons of the kidneys serve?
blood filtration
What are the two main parts of a nephron?
- Renal capsule
- Renal tubules
What are characteristics of the renal capsule?
- contians Bowman’s capsule (glomerulus)
- point of filtration
- always found in cortex of kidney
What three things are the renal tubules involved in?
- Secretion
- Concentration
- Rebsorption
What are the four renal tubules and which function(s) do they serve?
- Proximal convoluted tubule: Reabsorption
- Loop of Henle (renal loop): Concentration
- Distal convoluted tubule: Reabsorption/Secretion
- Collecting duct: Reabsorption/Secretion
What are the two types of nephrons?
- Cortical nephrons
- Juxtamedullary nephrons
What are the main characteristics of a cortical nephron?
- Fed by peritubular cappilaries in cortex around capsule, PCT and DCT
- Shorter loop that just dips into medullary layer of kidney
What are the main characteristics of a juxtamedullary nephron?
- Fed by vasa recta cappilaries in medula around nephron loop
- Longer loop that dips deeply into medullary layer of kidney
What is the blood flow from the heart to the glomerulus of the kidney?
ARSIA CAG
- Aorta
- Renal a.
- Segmental a.
- Interlobar a.
- Arcuate a.
- Cortical radiate a.
- Afferent arteriole
- Glomerulus
What is the blood flow from the glomerulus to the heart?
GEP CAIRI
- Glomerulus
- Efferent arteriole
- Peritubular capillaries/Vasa recta (pending nephron type)
- Cortical radiate v.
- Arcuate v.
- Interlobar v.
- Renal v.
- Inferior vena cava
What are the three functions of the nephron?
- Filtration
- Reabsorption and Secretion
- Concentration
Where does filtration take place in the kidney?
Bowman’s capsule
The glomerulus is…
the capillary within the bowman’s capsule
Describe the arterioles of the glomerulus.
- afferent arteriole brings blood to the glomerulus from the heart.
- efferent arteriole takes blood from glomerulus to the peritubular capillaries/vasa recta, and then back to heart.
Describe the endothelium of the glomerulus.
It is fenestrated and contains large holes to allow for easier diffuision of larger particles from the golmerulus to the bowmans capsule.
_____ pressure in the glomerulus allows for maximum exchange/_____.
Hydrostatic, diffusion
What causes the hydrostatic pressure within the glomerulus.
The afferent arteriole leading to the glomerulus is larger than the efferent arteriole that takes it away. Thus pressure builds in the glomerulus driving diffusion out into the bowman’s capsule
The ffiltration process of pressure/diffusion is called…
Glomerulus Filtration Rate (GFR)
How much filtrate is produced by both kidneys in 1 minute?
about 180mL/min
Regulation of filtrate is under _____.
renal auto-regulation.
Renal auto-regulation is controlled by what 3 things.
- Precapillary sphincters of the afferent arteriole
- Sympathetic Nervous System which can kick in and slow GFR
- Renin-Angiotensin II conversion which slows GFR.
Explain the Renin-Angiotensin II conversion process and its effect.
- When blood pressure is low in the kidney, they kidneys secrete renin
- Renin converts angiotensin into angiotensin I
- Angiotensin I is converted to Angiotensin II by an angiotensin converting enzyme
- Angio tensin II constricts efferent arterioles from the glomerulus
- Constriction of efferent arterioles causes a buildup of pressure in glomerulus
Reabsorption and secretion occur in…
the renal tubules
Define renal reabsorption.
Molecules in filtrate that leave nephron and are taken back by the body.
Reabsorption of electrolytes occurs in which tubule?
PCT
Sodium Chloride (NaCl), is a checmical that is reabsorbed in the _____ and helps regulate/produce _____.
PCT, osmolarity and electical gradients (action potential)
What are three other electrolytes reabsorbed in the filtration process.
- Potassium (K+)
- Phosphate (PO4)
- Magnesium (Mg++)
Besides electrolytes, what are some other items that are part of the reabsorption process of renal filtration?
- glucose and amino acids
- urea need in kidneys
- H2O that passively follows ions
All substances reabsorbed in PCT are picked up by what part of the vascular system?
peritubular capillaries
Define secretion in the renal filtration process.
Substances that are added to filtrate so the body can get rid of them.
In the renal filtration process, secretion occurs primarily where?
DCT
What substances can the renal tubules extract from the peritubular capillaries?
- Urea
- Hydrogen (H+) ions
- Bicarbonate (HCO3) ions
- Drug metabolites, toxins
What role do H+ and HCO3 ions serve in the filtration process?
Hydrogen and bicarbonate ions adjust pH
Water reabsorption/secretion occurs in…
loop of henle, DCT, collecting ducts
Water reabsorption/secretion is controlled by what three hormones?
- Aldosterone
- Natriuretic
- Antigen-diuretic
Describe aldosterone’s role in renal water reabsorption/secretion.
- Reabsorption of salt
- Secretion of potassium
- Acts upon DCT and CD. (Distal Convoluted Tubules and Collection Ducts)
- Produces RAAS system (Renin Angiotensin II Aldosterone System).
What role does RAAS play in filtration?
Increases water absroption, thus increasing blood volume and pressure.
Natriuretic hormones are secreted by the _____ in response to _____.
heart, high blood pressure
How do natriuretic hormones help lower blood pressure?
They inhibit sodium chloride reabsorption in kidney. this inhibits water reabsorption and reduces blood volume and pressure.
Will aldosterone raise or lower blood volume/pressure?
Raise by increasing water retention.
Will natriuretic hormones raise or lower blood volume/pressure?
Lower by reducing water retention
ADH stands for…
Anti-Diuretic Hormone
RAAS stands for…
Renin Angiotensin II Aldosterone System
What gland secretes ADH?
Pituitary
What role does ADH play in filtration?
- Increases water absorption, blood volume and pressure
How does ADH effect the renal reabsorption of water?
It makes the collecting ducts more permeable to water, thus forces water out of nephron causing more water to be reabsorbed and reducing loss to urine
Concentration of the renal filtration system occurs where?
Loop of Henle
Describe the process of concentration in the loop of Henle.
- Decending limb is permeable to H2O, so filtrate looses H2O and becomes more concentrated
- Concentrated filtrate then loops back up
- Ascending limb is impermeable to H2O, but permeable to salt. Sodium is reabsorbed at this point helping to maintain the brinebath and concentrating filtrate further.
- Urine enters collecting duct
The loop of henle travels into and out of the…
medulla of the kidney.
The medulla is _____ which means it has a higher _____ pressure.
hypertonic, osmotic
The loops of henle travel through the _____ of the medulla to assist the process of concentrating urine.
urea/brine bath
The two processes of contration are:
- Counter current multiplier
- Couter current exchange
The counter current multiplier refers specifically to the filtration process that occurs in…
- the loop of henle
The descending loop of henle is permeable to…
water
The ascending loop of henle is permeable to…
salt
Salt leaves the ascending loop of the loop of henle by what means?
Through salt/potassium/ATP pump
(active transport)
The salt reclaimed by the ascending loop of henle serves what purpose?
To maintain the urea/brine bath of medulla.
The ascending loop of henle makes its way to
the DCT
The descending loop of henle is coming from…
the PCT
Filtrate in the bottom loop of the loop of henle is in a ______ state.
super concentrated
The counter current exchange process of concentration is for the purpose of
reabosorption of material that has left the nephron.
How does the process of counter current exchange help concentrate the filtrate.
By absorbing the material that has left the nephron and taking it away to be used by the body.
What part of the nephron filtration system takes care of the reabsorption of materials that have been diffused out of the nephron?
The vasa recta
What layer of the kidney is the vasa recta located?
medulla
What layer of the kidney are the peritubular capillaries found?
Cortex
What is the relation of blood flow in the vasa recta in contrast to the loop of henle?
Vasa recta on the descending loop of henle has an ascending blood flow where the vasa recta on the ascending side has a descending blood flow.
The vasa recta is _____ to the extracellular fluid around it.
isotonic
The vasa recta also assit in the maintenance of
the urea/brine bath of the medulla
Regulation of urine volume occurs in…
the collecting ducts
The collecting tubes contain receptors for _____ and _____ which control how much _____ is reabsorbed.
ADH, Aldosterone, water
How do ADH and aldosterone help regulate water retention?
By increasing the permeablity of the collecting ducts.
more water = _____ osmolarity
less
Less osmolarity inhibits
ADH and aldosterone.
Less osmolarity makes the ducts _____ permeable to water.
Less
With low osmolarity, _____ water is released and ____ is absorbed.
more, less
With high osmolarity, _____ water is released and ____ is absorbed.
less, more
Too little water =
higher osmolarity
Higher osmolarity activates
ADH and aldosterone
High osmolarity makes the collecting ducts _____ permeable to water.
more
What is the path of exit for urine, starting at the collecting ducts?
- Collecting ducts to renal pelvis
- Renal pelvis to ureter
- Ureter to urinary bladder
- Urinary bladder to urethra
The urinary bladder contains _____ that let us know when its time to pee.
stretch receptors
What does the external sphincter of the bladder do?
Controls turin flow from bladder to urethra