1
Q
Components of the urinary system
A
kidney
ureters
urinary bladder
urethra
NO ACESSORY ORGANS
2
Q
Kidney; components of the urinary system
A
Paired organs
2 kidneys
3
Q
Ureters; components of the urinary system
A
- Each kidney has a ureter
- Filtered fluid travels through the ureter
*Brings fluid from the kidneys to the urinary bladder
4
Q
Urinary bladder: components of the urinary system
A
Storage tank for urine
5
Q
Urethra; components of the urinary system
A
- Tube that carries fluid to outside the body
- The male urethra carries both reproductive fluid and urine
- The female urethra only carries urine
6
Q
Functions of the urinary system (8 things)
A
- fluid filtration
- regulates blood volume
- maintains salt/water balance
- maintains acid/base balance
- gluconeogenesis
- renin production
- erythropoietin production
- activates vitamin D
7
Q
Fluid filtration; Functions of the urinary system
what filter what?
A
The kidneys filter plasma
-Plasma is the fluid/liquid portion of the blood
8
Q
Regulates blood volume; Functions of the urinary system
A
By increasing the amount of fluid filtered in the kidneys, the amount of fluid in circulation decreases
-Increasing the amount of fluid in the urinary system will decrease blood volume
This also changes blood pressure because changing blood volume causes a change in blood pressure
9
Q
Maintains salt/water balance; Functions of the urinary system
A
affects the tonicity of the body
10
Q
Maintains acid/base balance; Functions of the urinary system
A
plays a role in regulating pH
11
Q
Gluconeogenesis; Functions of the urinary system
A
- Occurs predominantly in the liver
- Also occurs in the kidneys
12
Q
Renin production; Functions of the urinary system
A
leads to the production of aldosterone by the adrenal cortex
13
Q
Erythropoietin production; Functions of the urinary system
A
this is the hormone responsible for the production of red blood cells
14
Q
Activates VITAMIN D: Functions of the urinary system
A
GET THAT DDDDD
15
Q
Structure of the kidney (10 items)
A
Capsule Cortex Medulla Renal Pelvis Renal Pyramids Renal Columns Major calyces Minor calyces Hilum Renal Sinus
16
Q
Capsule; struc of kidney
A
Outermost portion of the kidney
External covering of the kidney
17
Q
Cortex; structure of kidney
A
Superficial/outer region of the kidney
18
Q
Medulla; structure of kidney
A
Deep/inner region of the kidney
19
Q
Renal pelvis; structure of kidney
A
Flat part of the kidney prior to the ureter
20
Q
Renal pyramids; structure of kidney
A
- Triangle shaped structures
- Stripes in the pyramids are collecting ducts
21
Q
Renal Columns; structure of kidney
A
- Rectangular/columnar structures in between pyramids
- Inward extension of the cortex into the medulla
22
Q
Major calyces; structure of kidney
A
- Where the minor calyces empty into
- Where the minor calyces merge
23
Q
Minor calyces; structure of kidney
A
- Where collecting ducts end
- Where renal pyramids empty into
24
Q
Hilum; structure of the kidney
A
indentation of the kidney
25
Renal sinus; structure of kidney
Located within the renal pelvis
Where all major calyces dump into prior to fluid going into ureter
26
SUPPORTIVE layers of the kidney
Renal capsule
Adipose capsule
Renal fascia
27
Renal capsule; SUPPORTING LAYER OF KIDNEY
Outermost layer of the kidney
Defines the border/edge of the kidney itself
28
Adipose capsule; SUPPORTING LAYERS IN KIDNEY
Kidneys are enveloped by adipose tissue:
- Functions in cushioning/protection
- Functions in insulation
29
Renal Fascia; SUPPORTING LAYERS IN KIDNEY
HOLDS the kidneys to the abdominal wall
30
Nephron
The nephron is the functional structure of the kidney
Each kidney has more than 1 million nephrons
31
Glomerulus (differentiate nephrons)
Capillary bed of the kidney
-Specialized capillary bed
Unique in that it is between two arterioles instead of an arteriole and a venule
-Because of this, blood pressure here is higher than any other capillary bed
32
Parts of Renal tubule (surrounding of the capillary bed)
1Glomerular/ Bowman's Capsule
2. Proximal convoluted tubule
3. Loop of henle
4. Distal convoluted tubule
33
Glomerular/Bowman’s Capsule;
Parts of Renal tubule (surrounding of the capillary bed)
The capsule that surrounds the glomerulus
34
Proximal convoluted tubule;
Parts of Renal tubule (surrounding of the capillary bed)
Part of the tube closest to the glomerular capsule
35
Loop of HENLE;
Parts of Renal tubule (surrounding of the capillary bed)
Part of the tube that descends/ascends towards/from the medulla
36
Distal convoluted tubule;
Parts of Renal tubule (surrounding of the capillary bed)
connected to the loop of henle
37
Collecting ducts (differentiate nephrons)
WHAT DO THEY MAKE?
CONNECT TO WHAT?
Make up the renal pyramid
Connects to the distal convoluted tubule
38
Renal corpuscle;
Glomerulus + Bowman’s capsule
* Fluid goes from the glomerulus into Bowman’s capsule and into the renal tubule
* A collecting duct can connect to several renal tubules
39
Cortical nephron
When most of the nephron is in the cortex of the kidney
85% of the nephrons in our body are cortical nephrons
40
Juxtamedullary nephron
When the loop of Henle goes deep into the medulla
15% of the nephrons in our bodies are juxtamedullary nephrons
41
What does each nephron produce?
What do juxtamedullary nephrons produce?
- urine with a different concentration
- Juxtamedullary nephrons produce a more concentrated urine
When getting dehydrated, you use more juxtamedullary nephrons to conserve water and concentrate the urine being excreted
42
Nephron Vasculature; structures
```
afferent arteriole
efferent arteriole
glomerulus
peritubular capillaries
vasa recta
```
43
Afferent arteriole;
Nephron Vasculature structures
Vessel that delivers blood to the glomerulus
44
EFFERENT arteriole;
Nephron Vasculature structures
Vessel that carries blood away from the glomerulus
45
Glomerulus;
Nephron Vasculature structures
Capillary bed between the afferent and efferent arterioles
46
Peritubular capillaries;
Nephron Vasculature structures
- Kidneys also have a true capillary bed
- Efferent arteriole feeds into the peritubular capillaries
- Surround renal tubule
47
Vasa recta;
| Nephron Vasculature structures
Same as peritubular capillaries, but these are located on the juxtamedullary nephron
48
Juxtaglomerular Apparatus
Modification where the distal convoluted tubule runs against the afferent arteriole
The walls of both the distal convoluted tubule and the afferent arteriole are modified
49
What cells make up the Juxtaglomerular Apparatus?
```
macula densa cells
Juxtaglomerular cells (JG CELLS)
```
50
MACULA densa cells; cells that make up Juxtaglomerular Apparatus
Modified cells in the walls of the distal convoluted tubule
-Function as chemoreceptors
Detect differing concentration of solutes from filtrate
Activation of these cells can affect the diameter of blood vessels
Activation of these cells can activate JG cells
51
Juxtaglomerular CELLS/JG CELLS;
| cells that make up Juxtaglomerular Apparatus
Modified smooth muscle cells located in the afferent arteriole
Secrete renin
52
Where is the juxtaglomerular apparatus found ?
in both cortical/juxtamedullary nephrons
53
Filtration membrane components
fenestrated endothelium
podocytes
basement membrane
54
Fenestrated endothelium;
| Filtration membrane components
Allows everything (plasma, solutes, proteins) to pass through the capillary bed except blood cells
55
Podocytes;
Filtration membrane components
Cells around the basement membrane
Have extensions called pedicels
Pedicels are impermeable
Podocytes reduce the area that filtration can occur
Create filtration slits
-Only place things can leave from is where podocytes and their extensions are not present
56
Basement membranes;
Filtration membrane components
Wraps the capillaries
Functions in limiting the size of what can pass out of the cells
Holds electrical charges
- If the solute has the same charge, it cannot pass through the basement membrane
- Repels proteins from leaving circulation
Besides the charge, it is a nonselective process
57
Describe the process of urine formation. Include the role of pressure in controlling the rate of filtration. Compare the events that occur at different portions of the nephron.
Plasma and filtrate are essentially the same in composition, but filtrate lacks common blood proteins
-Filtrate will have water, nutrients (glucose and amino acids), ions (sodium and chloride), wastes (urea, uric acid)
58
Glomerular filtration; process of urine formation
The filtering movement of plasma from the bloodstream into the kidney tubule
Passive, nonselective process
-Only selectivity comes from the filtration membrane
Filtrate is formed from the plasma
59
Tubular reabsorption;
| process of urine formation
Removal of materials from the filtrate back into circulation
-Movement of materials from the kidney tubules back into the blood capillaries
Can be an active or passive process depending on the concentration gradient
Humans reabsorb all glucose and amino acids from the filtrate
Reabsorb most of the water and most of the ions
-Reabsorption of these two classes is greatly affected by hormones
Can occur in the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule
-Can occasionally occur in the collecting duct
60
Tubular Secretion;
| process of urine formation
Moves of material from the capillaries into the renal tubule
-Gives a second chance to remove things from the bloodstream to excrete out of the body
Mostly occurs in the proximal convoluted tubule
Mostly occurs in the cortex of the kidney
61
Types of filtration pressures;
| process of urine formation
Glomerular hydrostatic pressure
Colloid osmotic pressure of intracapsular space
Colloid osmotic pressure of glomerular blood
Capsular hydrostatic pressure
62
Glomerular hydrostatic pressure
| filtration process of urine formation
Pressure of blood inside the glomerulus
Responsible for movement of plasma out of the blood vessels to become filtrate
63
Colloid osmotic pressure of intracapsular space
| filtration process of urine formation
Pressure that draws fluid out into Bowman’s capsule due to the presence of proteins
Typically zero because proteins can’t get past the filtration membrane
64
Colloid osmotic pressure of glomerular blood
| filtration process of urine formation
Pressure that draws fluid into the glomerulus from Bowman’s capsule due to the presence of proteins in the vessel
65
Capsular hydrostatic pressure
| filtration process of urine formation
Fluid pressure inside the capsule
Works in opposition to glomerular hydrostatic pressure
Under normal circumstances, this pressure is lower than glomerular hydrostatic pressure
-This keeps a net flow of fluid out of the glomerulus into the capsule/tubule
66
Renal Blood Flow and Glomerular Filtration Rate
AFFERENT: CONSTRICTION
Renal Blood Flow DECREASES
Glomerular Filtration Rate DECREASES
67
Renal Blood Flow and Glomerular Filtration Rate
AFFERENT: DILATION
Renal blood flow INCREASES
Glomerular Filtration INCREASES
68
Renal Blood Flow and Glomerular Filtration Rate
EFFERENT CONSTRICTION
Renal blood flow DECREASES
Glomerular filtration rate INCREASES
69
Renal Blood Flow and Glomerular Filtration Rate
EFFERENT DILATION
Renal Blood Flow INCREASES
Glomerular filtration Rate DECREASES
70
Identify factors that can affect renal filtration, and discuss the effects of each.
The kidneys prefer to keep the amount of filtrate produced relatively constant
-The following examples display what the kidneys would do if blood pressure was low and the kidneys needed to increase filtration rate in response to this stimulus
71
Intrinsic filtration regulation mechanisms (factors that can affect renal filtration)
Myogenic mechanism of autoregulation
Tubuloglomerular mechanism of autoregulation
72
Myogenic mechanism of autoregulation;
Intrinsic filtration regulation mechanisms (factors that can affect renal filtration)
When there is low blood pressure, the afferent arteriole will dilate to allow more plasma to be filtered in the glomerulus
Increases filtration of glomerulus
73
Tubuloglomerular mechanism of autoregulation;
Intrinsic filtration regulation mechanisms (factors that can affect renal filtration)
Look at the concentration of filtrate in the distal convoluted tubule
If the concentration of filtrate is low in the distal convoluted tubule, you get a dilute urine
Macula densa cells detect the low concentration of the filtrate
Causes vasodilation of the afferent arteriole
Filtration increases
74
Extrinsic Filtration Regulation controls (factors that can affect renal filtration)
Neural control (low bp)
Hormonal control over filtration
75
```
Neural control (low blood pressure);
Extrinsic Filtration Regulation controls (factors that can affect renal filtration)
```
Sympathetic nervous impulses cause the release of norepinephrine
Norepinephrine causes systemic vasoconstriction
-Systemic vasoconstriction causes an increase in blood pressure
The resulting increase in blood pressure will increase filtration
If we need to change the distribution of blood to the skeletal muscles during a fight or flight scenario, sympathetic nervous impulses constrict blood flow to the kidney and redirect blood flow to the skeletal muscles
76
Hormonal control over filtration;
| Extrinsic Filtration Regulation controls (factors that can affect renal filtration)
JG cells in the modified walls of the afferent arteriole function as baroreceptors (detect blood pressure)
When JG cells detect a low blood pressure, the JG cells release renin
- Renin combines with angiotensinogen to make angiotensin II
- -Causes the adrenal cortex to release aldosterone
Aldosterone causes an increase in sodium reabsorption
- If more sodium is reabsorbed, osmotic gradient causes water to be reabsorbed
- Water goes back into the bloodstream
- Blood volume increases; blood pressure increases
Increase in blood pressure will increase filtration
77
OTHER factors that can affect renal filtration
Prostaglandins
Nitric oxide
Adenosine
Endothelin
78
Prostaglandins; OTHER factors that can affect renal filtration
Local signaling molecule
Acts as vasodilators in the kidney
Increases GFR
79
Nitric oxide;OTHER factors that can affect renal filtration
Dilates blood vessels
Increases GFR
80
Adenosine; OTHER factors that can affect renal filtration
In the kidney, it acts as a vasoconstrictor
| -Adenosine acts as a vasodilator in other parts of the body
81
What does endothelin cause?
| OTHER factors that can affect renal filtration
Causes vasoconstriction
82
Tubular reabsorption (factors that can affect renal filtration)
Primarily a transepithelial process
Luminal barrier of renal tubule - basolateral barrier - interstitial space - bloodstream
Active and passive process
- Channel proteins allow some things out passively; some things require energy to pass through
- Water moves based on the osmotic gradient
83
Tubular reabsorption FACTS (factors that can affect renal filtration)
Cells that make up the renal tubule have tight junctions
-These junctions are impermeable
Ions can move across paracellular channels
Most abundant ion in filtrate is sodium
-roughly 99.5% of sodium is reabsorbed
84
Proximal convoluted tubule;
Actions by region (factors that can affect renal filtration)
Where most reabsorption occurs
100% of glucose, amino acids, and lactate
65% of sodium and water reabsorbed here
85
Descending Loop of Henle;
| Actions by region (factors that can affect renal filtration)
Permeable to water, impermeable to solutes
Water moves passively from the descending loop into the interstitial space
-From the interstitial spaces, it will pass into the peritubular capillaries or the vasa recta
86
Ascending loop of Henle;
| Actions by region (factors that can affect renal filtration)
Permeable to solutes, impermeable to water
Aldosterone increases sodium reabsorption in the ascending loop of Henle
-This increase in sodium reabsorption leads to an increase in water reabsorption
87
Distal convoluted tubule;
| Actions by region (factors that can affect renal filtration)
Continued reabsorption based on the body’s needs
Aldosterone increases sodium reabsorption in the distal convoluted tubule and collecting duct
ADH causes increase water reabsorption in the distal convoluted tubule and collecting duct
88
Collecting duct;
| Actions by region (factors that can affect renal filtration)
Continued reabsorption based on the body’s needs
Aldosterone increases sodium reabsorption in the distal convoluted tubule and collecting duct
ADH causes increase water reabsorption in the distal convoluted tubule and collecting duct
89
Reabsorption in the distal convoluted tubule and the collecting duct are affected by what?;
Actions by region (factors that can affect renal filtration)
-ADH (antidiuretic hormone)
The collecting duct is impermeable to water unless ADH is active
ADH opens aquaporins
90
When consuming alcohol or caffeine what is suppressed and what closes?
-ADH is suppressed and aquaporins close
Aquaporins are membrane proteins that allow the movement of water.
-When aquaporins are closed, water cannot leave the collecting duct and urine formation increases
Anatomy and Physiology
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