Lecture 13 Flashcards
Four main organs of the urinary system
1.
2.
3.
4.
- Kidneys (2)
- Ureters (2)
- Urinary Bladder
- Urethra
Three primary functions of the kidneys? with examples
1.
2.
3.
- Synthetic function: erythropoietin; 1,25 dihydroxyvtiamin D3 (calcitriol); renin
- Excretion: metabolic waste products (urea, creatinine, uric acid, bilirubin) and ingested toxins (drugs, pesticides)
- Regulation: water & electrolytes; acid-base; arterial BP
____________ are the structural and functional units of the kidneys (the filtering units)…. responsible for filtering _________ and producing ______
nephrons; blood; urine
2 types of nephrons:
- ______________ nephrons (15%): closer to the medulla
- ____________ nephrons: located almost entirely in the cortex
- juxtramedullary
- cortical
Each nephron consists of two major parts:
1. ___________: filters the blood plasma
2. ___________: converts the filtrate to urine
- renal corpuscle
- renal tubule
Renal corpuscle: two main structures
1. _________________: cup-shaped hollow structure; completely surrounds the __________
2. _________________: a knot of capillaries wrapped by ____________
- bowman’s capsule; glomerulus
- glomerulus; podocytes
Glomerulus is the main __________ unit of the kidney and is located at the ___________ of the nephron
filtering; beginning
Renal corpuscle
- _______________: inside the capsule and surrounds the glomeruli
bowman’s space
_______________: a process in which water and some solutes in the blood plasma pass from __________ of the glomerulus into the capsular space of the nephron
- all takes place in the ______________, specifically the __________
Glomerular filtration; capillaries
- renal corpuscle; glomerulus
- _____________: vessel responsible for supplying blood to the glomerulus
- _____________: structure that filtrated blood (_______) enters before flowing into the _______ _______ lumen
- ____________: vessel that leaves the capsule and carries blood way
- efferent arteriole
- glomerular capsular space; filtrate; renal tubule
- afferent arteriole
Net Filtration Pressure (NFP): the _______ pressure that promotes ____________ (i.e, the movement of small _______ and _______ from the capillaries of the glomerulus towards the capsular space)
- ______ mmHg
total; filtration (solutes; water)
- 10
3 main pressures that determine the NFP at the glomerulus
- ______________: is the blood pressure in glomerular capillaries
- ____________: mainly due to the presence of proteins (e.g. albumin) in blood plasma
- ___________: exerted by fluid already in the glomerular capsule
- Glomerular Hydrostatic Pressure (GHP)
- Glomerular Colloid Osmotic Pressure (GCOP)
- Capsular Hydrostatic Pressure (CHP)
- How do you calculate the NFP?
- If GHP= 65 mmHg, GCOP: 20 mmHg, CHP= 15 mmHg, what is the value of NFP?
- NFP= Forces favoring filtration (GHP) - Forces that oppose it (GCOP + CHP)
- 65 mmHg - (20+15 mmHg)= 30 mmHg
- When the NFP is positive: there is net fluid _________
- When the NFP is negative: there is net fluid _________
- filtration
- reabsorption
3 barriers that constitute the filtration membrane
1.
2.
3.
- Fenestrated (with pores) endothelium of the capillary
- Basement membrane of glomerulus
- Filtration slits between pedicels
Fenestrate endothelia of the capillary
- prevents filtration of ______ _______
Basement membrane of glomerulus
- consists of a proteoglycan gel which prevents filtration of ________ proteins
Filtration slits between pedicels
- ________ charged- obstacle for _______ ______
- prevents filtration of _____-sized proteins
- blood cells
- large
- negatively; large anions
- medium
__________: specialized epithelial cells that cover the outer surfaces of the glomerular capillaries
- their _____ ________ (_________) wrap around the capillaries and interdigitate with each other; ___________
podocytes
- foot processes (pedicels); cytoplasmatic extensions
Substances found in kidney filtrate:
- _________
- _________
- _________
- _________
- _________
Substances NOT found in kidney filtrate
- __________
- __________
- free amino acids
- nitrogenous wastes
- water
- small ions
- Glucose
- blood cells
- plasma proteins (e.g. albumin)
Main nitrogenous wastes products of the body?
- ammonia
- urea
- uric acid
- creatinine
Nitrogenous waste products:
- Ammonia and Urea: by-product of ______ catabolism
- Uric acid: produced by the catabolism of ___________
- Creatinine: breakdown product of __________
- protein
- nucleic acids
- creatine
- ________ is the amount of _______ formed by the two kidneys combined
- males: _____ mL/min (______ L/day)
- females: _____mL/min (_____ L/day)
- Glomerular Filtration Rate (GFR); filtrate
- 125 (180)
- 105 (150)
GFR is…
- too low: fluid flows _______ through the renal tubules, they _________ wastes that should be eliminated in the urine
- too high: fluid flows through the renal tubules too ________ for them to _________ ______ and ________—> leads to __________ and __________ depletion
- sluggish; reabsorb
- rapidly; reabsorb; water; solutes dehydration; electrolyte
Intrinsic and Extrinsic controls of the GFR
Intrinsic:
- _______ responses initiated and maintained by the _____________
- main goal: ___________ regulate ______ and ________ the glomerulus from changes in _____ that could damage them
- local; kidneys
- directly; GFR; protect; BP
Intrinsic and Extrinsic controls of the GFR
Extrinsic:
- _________ (__________ responses)
- ________ affect GFR
- main goal: control and maintain _________ ______
- They are activated for example when there is a vast decrease in _____(that can compromise life) to restore the ______
- outside (systemic)
- indirectly
- systemic BP
- BP; BP
The two intrinsic auto regulation mechanisms for maintaining GFR?
1.
2.
What do these have in common?
- both modify the ________ of the __________ arteriole in response to moderate changes in ______
- Myogenic mechanism
- Tubuloglomerular feedback
- diameter; afferent; BP
How changes in the afferent arteriole’s diameter affect the GFR…
- afferent arteriole diameter increases (________ of smooth muscle)= _____ blood will enter the glomerulus and can be filtered…. GFR ______
- afferent arteriole diameter decreases (_______ of smooth muscle )= ______ blood will enter the glomerulus…. GFR ________
- relaxation; more; increase
- contraction; less; decrease
The myogenic mechanism is based on the tendency of smooth muscle to _______ when ________
- when BP increases, the hydrostatic pressure against the walls of the _________ arteriole _________
- this results in the activation of ______ ________ located at the walls of the arteriole
- this activation will result in _________ of smooth muscle (_____________) and _______ in the GFR
- In case of low BP, the afferent arteriole smooth muscle _________ (________) allowing blood to flow easily into the glomerulus, which ________ the GFR
- contract; stretched
- afferent; increases
- stretch receptors
- contraction (vasoconstriction); decrease
- relaxes (vasodilation); increases
Tubuloglomerular feedback: it involves the _______________ ______________
juxtaglomerular apparatus
The 3 components of juxtaglomerular apparatus
1. ____________: lining the wall of the _____/_______ ______ tubule
2. ___________: inside the _________ and in between the _________
3. _____________: modified smooth muscle cells wrapped around the _______ arteriole
- Macula densa: loop/distal convoluted
- Mesangial cells: glomerulus; capillaries
- Granular cells: afferent
How does the juxtaglomerular apparatus regulate the GFR?
1. _________ cells ______ tubule flow [NaCl]
- When GFR ____: these cells secrete ______
2. _________ cells metabolize ______ to _____________
3. ___________ cells constrict the __________ arteriole in response _____________
- Macula densa; sense
- increases; ATP - Mesangial; ATP; adenosine
- Granular; afferent; adenosine
Angiotensionogen is produced in the _______ and is ________
liver; inactive
Renin is produced in the ________________ cells
- its an ________ that converts angiotensinogen into _______________
- Renin is released when there is _______ BP which causes a _______ in the GFR
juxtaglomerular
- enzyme; angiotensin I
- low; decrease
ACE= ________________ and is produces primarily in the vascular endothelium of the _______ and ________
- converts angiotensin-I into ________________
Angiotensin-converting enzyme; lungs; kidneys
- angiotensin-II
- what enzyme converts angiotensinogen into angiotensin-I?
- what enzyme converts angiotensin-I into angiotensin-II?
- renin
- ACE
Effects of Angiotensin II (RAAS)
- promotes _________ of __________ arterioles
- promotes __________ of ________ blood vessels
- vasoconstriction; efferent
- vasoconstriction; systemic
Effects of Angiotensin II (RAAS): Salt and water retention
- promotes the reabsorption of sodium ions from the urine by
1. stimulating the ________ _________ in the ______
2. promoting _________ release from the adrenal gland
- Na+/H+ antiport; PCT
- aldosterone
Order in which fluid flows through the kidney (from the glomerulus to the papillary duct)
1.
2.
3.
4.
5.
- glomerulus
- Proximal Convoluted tubule
- Loop of Henle (nephron loop)
- Distal convoluted tubule
- Collecting duct
- Papillary duct
What structures converge to form a major calyx?
2-3 minor calyces
Path of the urine through the urinary system (start with glomerulus:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
- glomerulus
- Proximal Convoluted Tubule (PCT)
- Loop of Henle (nephron loop)
- Distal Convoluted Tubule (DCT)
- Collecting Duct (CD)
- Papillary Duct
- Minor calyx
- Major calyx
- Renal pelvis
- Ureter
- Urinary Bladder
- Urethra
