Ch 25 - Urinary System

Front 1

Describe the function of kidneys.

Back 1

1. Filter blood and form urine.
2. Involve in the homeostatic control of fluid volume and composition and acid/base balance.

Front 2

Describe the function of ureters.

Back 2

Transport urine from kidneys to bladder.

Front 3

Describe the function of urinary bladder.

Back 3

Temporarily stores urine and releases urine.

Front 4

Describe the function of urethra.

Back 4

Transports urine from the bladder to the urinary orifice for exit

Front 5

Name all the organs in the urinary system.

Back 5

Two kidneys, two ureters, one urinary bladder, and one urethra.

Front 6

Describe the anatomical structures of renal capsule.

Back 6

Connective tissue sac covering kidney.

Front 7

Describe the anatomical structures of renal cortex.

Back 7

The most superficial region in light color in kidneys.

Front 8

Describe the anatomical structures of renal medulla.

Back 8

Deep to the cortex, which is reddish-brown tissue which exhibits cone-shaped tissue mass.

Front 9

Describe the anatomical structures of renal sinus.

Back 9

A cavity within the kidney which renal hilum leads into and which is occupied by the renal pelvis, renal calyces, blood vessels, and nerves.

Front 10

Describe the anatomical structures of renal pelvis.

Back 10

Fatty tissue which contains both major and minor calyces and the renal sinus which gives rise to the ureter.

Front 11

Describe the anatomical structures of renal hilus.

Back 11

Indentation for entrance of the renal artery and exit of the renal vein and ureter.

Front 12

Describe the anatomical structures of renal papillae.

Back 12

The apex of each pyramid which points internally to renal pelvis.

Front 13

Describe the anatomical structures of renal columns.

Back 13

Contains inward extensions of cortex, which separates the pyramids.

Front 14

Describe the anatomical structures of renal pyramids.

Back 14

Pyramid-shaped medullas which contain Loop of Henle's and collecting ducts.

Front 15

Describe the anatomical structures of major calyces.

Back 15

Branching extensions of the renal pelvis which form two or three minor calyces.

Front 16

Describe the anatomical structures of minor calyces.

Back 16

Cup-shaped areas which receive urine draining thru renal papillae at bottom of pyramid.

Front 17

Describe the flow of urine from minor calyces to outside body.

Back 17

Urine flows from minor calyces into major calyces and then into the renal sinus -> ureters -> exits kidney at hilus -> bladder -> urethra

Front 18

Describe the structure of glomerulus in the nephron.

Back 18

Each nephron consists of a glomerulus which is a tuft of capillaries from afferent arteriole and a renal tubule. Mostly located in cortex.

Front 19

Describe the structure of Bowman's capsule in the nephron.

Back 19

A.k.a glomerular capsule surrounding the glomerulus which is beginning of the nephron tubule. Mostly located in cortex.

Front 20

Describe the structure of proximal convolutions in the nephron.

Back 20

Initial winding portion of tubule surrounded by peritubular capillaries which extends to make the loop of Henle.

Front 21

Describe the structure of descending and ascending limbs of the loop of Henle in the nephron.

Back 21

- The portion of the nephron that leads from the proximal straight tubule to the distal convoluted tubule.
- Surrounded by peritubular capillary network, including vasa recta at bottom of loop (cortical nephron are not surrounded)
- Mostly in meddulary pyramids for juxta medullary hephrons, and mostly in cortex for cortical hephrons.

Front 22

Describe the structure of distal convolutions in the nephron.

Back 22

Final winding portion of tubule surrounded by peritubular capillary work. Mostly in cortex.

Front 23

Describe the function of distal convolutions in the nephron.

Back 23

Transports and modifies filtrate via tubular reabsorption and secretion.

Front 24

Describe the structure of collecting ducts in the nephron.

Back 24

several tubules empty in here and terminates into minor calynx in renal pelvis via renal papillae. Mostly in medullary pyramid

Front 25

Describe the function of collecting ducts in the nephron.

Back 25

Concentrates (via fac.tubular reabsorption of water) and collects urine (first time the waste product is called urine)

Front 26

Describe the structure of afferent and efferent arterioles in the nephron.

Back 26

Capillaries which run in parallel in the glomerulus. This capillary beds are both fed and drained by arterioles.

Front 27

Describe the structure of peritubular capillaries in the nephron.

Back 27

Arise from the efferent arterioles draining the glomeruli and cling closely to adjacent renal tubules and empty nearby venules.

Front 28

Describe the structure of vasa recta in the nephron.

Back 28

Formed bundles of long straight vessels that extend deep into the medulla paralleling the longest loops of Henle.

Front 29

Name three basic steps of urine formation.

Back 29

1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion

Front 30

What is the filtrate?

Back 30

Plasma minus blood cells and proteins

Front 31

Describe the Glomerular filtration.

Back 31

Blood is filtered by glomerular capillaries; material is pushed through squamous ET capillary wall and podocyte slits into Bowman's capsule. Then, filtrate flows through nephron.

Front 32

Describe the Tubular Reabsoption.

Back 32

Water, nutrients, and electrolytes are transported out of the tubules and into the peritubular capillaries

Front 33

Describe the Tubular Secretion.

Back 33

Peritubular capillaries secrete solutes into the filtrate.
Solutes include substances in excess in blood, blood substances that need to be lowered to maintain homeostasis, and medications and hormones.

Front 34

Three processes of urine formation change a high volume of dilute filtrate in Bowman's capsule into what?

Back 34

A concentrated low volume of urine

Front 35

Filtrate (urine) flows from a collecting duct to where?

Back 35

Renal capillae -> minor calyx -> major calyx -> renal pelvis -> ureter

Front 36

Describe the Glomerular membrane.

Back 36

Squamous ET capillary walls with pores -> basement membrane -> Bowman's capsule wall (simple squamous ET with podocytes and filtration slits)

Front 37

As filtrate moves through the nephron, its volume and composition are modified by ... ?

Back 37

Tubular reabsorption and secretion

Front 38

Three processes of formation of urine change a high volume of dilute filtrate in Bowman's capsule into what?

Back 38

A concentrated low volume of urine

Front 39

Bowman's capsule wall consists of what?

Back 39

Simple squamous ET with podocytes and filtration slits

Front 40

What causes the movement of the fluid from Bowman's capsule wall into the lumen of nephron tubule?

Back 40

Pressure gradient of arteliole's BP

Front 41

What consists of the filtration membrane?

Back 41

It lies between the blood and the interior of the glomerular capsule. ET of glomerular capillaries; basement membrane; foot processes of podocyte of glomerular capsule

Front 42

What contains in initial filtrate?

Back 42

Water, glucose, amino acids, other nutrients, electrolytes(ions), and wastes.

Front 43

Wastes in initial filtrate include...?

Back 43

Creatine, urea (deamination of amino acid), uric acid (nitrogen base of nucleic acid metabolism), and lactic acid (anabolic metabolism)

Front 44

Driving force in filtration pressure of Glomerular filtration is ...?

Back 44

Blood hydrostatic pressure which consists of cardiac output and resistance.

Front 45

Average BHP in glomerulii is what?

Back 45

55mmHg

Front 46

Why water and solutes of blood flow into PCT?

Back 46

BP is greater in glomerulus than in other capillaries, and the efferent arterioles have a smaller diameter than afferent arterioles.

Front 47

What is the average net filtration pressure and how to calculate it?

Back 47

GFP = BHP - (FHP + BOP) -> 55 - (30 + 15) = 10mmHg

Front 48

Average filtrate per minute is ...?

Back 48

125ml filtrate per min

Front 49

What is the first method of regulating GFR?

Back 49

Myogenic effect

Front 50

Regulation of filtration rate mostly depends on what?

Back 50

Capillary BP which can be altered by changes in afferent and efferent arterioles diameter.

Front 51

Dilation of afferent arteriole causes what?

Back 51

Raise volume of blood in glomerulii -> increase pressure -> increase GFR

Front 52

Constriction of afferent arterioles causes what?

Back 52

Blood flow is reduced -> lower the pressure -> decrease GFR

Front 53

Sympathetic stimulation of auto GFR regulation is triggered when...?

Back 53

Extreme stress or fluid loss when it is necessary to shut blood to vital organs.

Front 54

How does extrinsic control of autoregulation work when decrease in systemic BP ?

Back 54

Renin is released -> Angiotensin II is stimulated -> constricting systemic arterioles -> raising peripheral pressure -> systemic BP rise

Front 55

Intrinsic control of auto GFR regulation take over extrinsic control. True or False?

Back 55

False: extrinsic control take over intrinsic control

Front 56

What is the main purpose of intrinsic control of autoregulation?

Back 56

To maintain a constancy in GFR despite stress and BP changes within kidneys.

Front 57

Under myogenic control, rise in BP causes what?

Back 57

Afferent arteriole constricts so GP & GFR can stay the same.

Front 58

Under myogenic control, drop in BP causes what?

Back 58

Afferent arterioles dilate so GP & GFR stay the same.

Front 59

Where are Macula Densa cells located?

Back 59

In wall of ascending limb of Loop of Henle and the distal convolutions of tubule

Front 60

Macula densa cells detect what?

Back 60

Na+ and Cl- concentrations in filtrate

Front 61

How does Macula densa autoregulation work?

Back 61

Detect Na+ level (due to low GFR) -> chemical signal to afferent arteriole to dilate -> increase of flow of blood -> restore GFR

Front 62

Where are JG cells located?

Back 62

Located in the wall of the ascending limb of the loop of Henle and DCT

Front 63

Juxtaglomerullar Apparatus contains two cells. Each cell detects what?

Back 63

Granular cells are mechanoreceptors that sense BP in the afferent arteriole.
Macula densa cells are chemoreceptors that detect changes in NaCl of the filtrate.

Front 64

How do JG cells regulate GFR?

Back 64

Detect low GFR -> release of rennin by JG cells -> angiotensin reaction -> constricts efferent arterioles -> raise GP -> restore GFR

Front 65

How does Angiotensin II act to stabilize systemic BP and ECF fluid volume?

Back 65

1. As a powerful vasoconstrictor which activates smooth muscle of arterioles -> peripheral pressure rise -> raise arterial BP
2. By stimulating reabsorption of sodium by triggering the release of aldosterone from adrenal cortex -> BP rise & Blood volume rise

Front 66

What is the rate of GF and rate of urine formation?

Back 66

Rate of GF = 125ml/min
Rate of urine formation = 1ml/min

Front 67

How much of fluid is reabsorbed in the nephron tubule and collecting ducts?

Back 67

124ml

Front 68

100ml out of 124ml are removed in where and how?

Back 68

In the proximal convoluted tubule by sodium reabsorption followed by obligatory H2O reabsorption.

Front 69

7ml out of 24ml are absorbed by what and how?

Back 69

- Counter current multiplier mechanism.
- Cells of descending limb of Loop of Henle are permeable to water
- Cells of ascending limb pf Loop of Henle are permeable to sodium & impermeable to water

Front 70

What is going to happen with 17ml of fluid entering distal convoluted tubule?

Back 70

- 11-12ml are reabsorbed by obligatory reabsorption by aldosterone which increase sodium reabsorption
- Some are by facultative water reabsorption under influence of ADH

Front 71

How much of fluid enters the collecting duct?

Back 71

5-6ml

Front 72

How much of fluid is reabsorbed in the collecting duct and how?

Back 72

4ml are reasrobed by facultative H2O reabsorption under influence of ADH

Front 73

When the body is dehydrated, ADH will rise or drop? Why?

Back 73

Low H2O -> low blood -> low BP -> raise AHD

Front 74

Describe how H2O is obligated to follow Na+ in Tubular Reabsorption.

Back 74

PCT actively secrets Na+ into the peritubular capillaries in order to maintain the preset range of homeostatic sodium concentration of blood.-> water follows sodium under concentration gradient

Front 75

How does CCMM influence reabsorption in the collecting ducts?

Back 75

Movements of Na+ & water concentrates the fluid bathing in DCT & collecting ducts -> water diffuse out of the collecting ducts under influence of ADH.

Front 76

ADH is made in where and released from where?

Back 76

ADH is made in hypothalamus and stored & released from the posterior pituitary gland.

Front 77

ADH do what for water reabsorption?

Back 77

ADH increases permeability of DCT and collecting ducts by bounding cells.

Front 78

If the body H2O is in excess, how does ADH work?

Back 78

ADH secretion is decreased which decreases DCT and collecting duct permeability -> more water stays in filtrate and eventually excreted from the body.

Front 79

If the body H2O is low, how does ADH work?

Back 79

ADH secretion is increased which increases DCT and collecting duct permeability -> more water is absorbed back into the blood.

Front 80

Final reabsorption of Na+ occurs by what? Where?

Back 80

This occurs in DCT as needed to maintain sodium balance and blood volume. This is triggered by macula densa cells.

Front 81

Aldosterone targets what and how does it work?

Back 81

Cells of DCT and causes them to release Na+ to be reabsorbed into the peritubular capillaries -> water follows -> correct blood volume -> increase BP -> increase GFR

Front 82

Rennin & angiotensin pathway affect what?

Back 82

Aldosterone and ADH

Front 83

Describe the final composition of urine.

Back 83

H2O (95%)
Urea (from amino acid metabolism)
Na+
K+
Hydrogen phosphate ion
Sulfate ion
Creatine (from muscle metabolism)
Uric Acid (from nucleic acid metabolism)
Calcium ion

Front 84

What is/are reabsorbed in PCT?

Back 84

Na+ & H2O
Glucose
Amino acid
Other nutrients

Front 85

What is/are reabsorbed in the descending limb of Loop of Henle?

Back 85

H2O

Front 86

What is/are reabsorbed in the ascending limb of Loop of Henle?

Back 86

Na+ & Cl-

Front 87

What is/are reabsorbed in DCT?

Back 87

Na+ & H2O

Front 88

Are there any secretions in DCT? If so, what is/are secreted?

Back 88

Main substance are drugs, medicines, excess hormones, creatine, and hydrogen & HCO3-

Front 89

Describe the Tubular Secretion and its importance.

Back 89

Blood substance move from peritubular capillaries into the filtrate of PCT & DCT. Especially, secretion in DCT is a final chance to get rid of blood materials which may be out of balance or were not filtered by the glomurulus initially.

Front 90

What is/are reabsorbed in collecting ducts?

Back 90

H2O

Front 91

Under Tubular Secretion, substances like K+, HCO3-, Ca+ are reabsorbed when ...?

Back 91

When the blood needs to a limited extent.

Front 92

Aldosterone is secreted from where?

Back 92

Adrenal cortex

Front 93

Aldosterone secretion targets what and how it works?

Back 93

Aldosterone targets cells in DCT and causes them to release sodium to be reabsorbed into peritubular capillaries.

Front 94

What are two major ways to raise blood volume and BP?

Back 94

Angiotensin pathway and aldosterone secretion

Front 95

Discribe the difference between cortical nephron and juxtamedullary nephron in terms of location.

Back 95

Cortical nephron - Loop of Henle is barely appearing in renal medulla.
Juxtamedullary nephron - entire Loop of Henle is appearing in renal medulla.
Bowman's capsules for both are located in renal cortex.

Front 96

Discribe the difference between cortical nephron and juxtamedullary nephron in terms of function.

Back 96

Cortical nephron - most of reabsorption and secretion occurs in its PCT.
Juxtamedullary nephron - most of CCMM occurs in its vasa recta.
=> due to no capillary in Loop of Henle of cortical nephron and PCT & DCT of juxtamedullary nephron

Front 97

Why is the reabsorption of nutrients (glucose, amino acid and etc) are rate-limited?

Back 97

They are reabsorbed by active transport since they are too big to simple-diffuse. They need aid of transport protein, so it is slower and thus rate-limited.

Front 98

Describe the abnormal constituents of urine.

Back 98

Glucose
RBCs
Hemoglobin
Blood protein
WBC/pus (infection)
Bile pigments (supposed to leave livers to duodenum)

Front 99

The abnormal constituents of urine appears under what kind of condition?

Back 99

Trauma, disease, stressors, too much eating or too much exercise

Front 100

What is the normal urine color?

Back 100

Clear to light yellow.

Front 101

Increased color of yellow in urine indicates what?

Back 101

Increased concentration of urine = ADH & aldosterone are working = Na+ or fluid imbalance

Front 102

pH of urine can vary from what to what?

Back 102

pH 4.5 to 8.0

Front 103

What is the specific gravity of normal urine?

Back 103

1.001 to 1.035

Front 104

If the specific gravity of urine is >1.035, it means ...?

Back 104

There is presence of abnormal chemicals in urine.

Front 105

Name two voiding reflex arcs.

Back 105

Parasympathetic reflex arc & Somatic reflex arc

Front 106

Describe the process of voiding reflex.

Back 106

1. Stretch receptors in bladder wall triggered by 200 ml of urine.
2. Afferent impulses from stretch receptors.
3. Efferent command to detrusor (push down urine) muscle which contracts and internal sphincter which relaxes
4. Voluntary efferent command to relax the external sphincter -> urination

Front 107

When a person chooses not to void, what control mechanism is working?

Back 107

Parasympathetic activity DOWN
Sympathetic & somatic motor nerves' activities UP

Front 108

External urethral sphincter is controlled by what?

Back 108

Somatic nervous system because it is skeletal muscle.

Front 109

Name a protein found in skeletal muscle and excreted in urine.

Back 109

Creatinine

Front 110

Where is the primary site of glucose and amino acid reabsorption?

Back 110

Proximal convoluted tubule

Front 111

Where is the site for sodium and water to be reabsorbed under hormonal influence?

Back 111

Distal convoluted tubule

Front 112

Name the mechanism which afferent arterioles constrict in response to a rise in blood pressure, thus restricting the flow of blood into the glomerulus.

Back 112

Myogenic mechanism

Front 113

Name an enzyme that catalyzes the formation of angiotensin I .

Back 113

Renin

Front 114

Name a powerful vasoconstrictor that also stimulates the secretion of aldosterone.

Back 114

Angiotensin II

Front 115

This promotes reabsorption of sodium at the distal convoluted tubule.

Back 115

Aldosterone

Front 116

This regulates water reabsorption at the distal convoluted tubule.

Back 116

ADH

Front 117

The most important factor affecting the glomerular filtration rate is what?

Back 117

Blood hydrostatic pressure

Front 118

If the efferent arteriole constricts while the afferent arteriole remains unchanged, the glomerular filtration rate decreases. True or False?

Back 118

False: if the efferent arteriole constricts while the afferent arteriole remains unchanged, the glomerular filtration rate increases. This will increase glomerular hydrostatic pressure.

Front 119

When macula densa cells in DCT detect too low sodium in the blood, what would happen?

Back 119

Macula dense cells send chemical messenger to afferent arterioles to dilate & to JG cells triggering their release of rennin -> angiotensin pathway, which affect ADH and aldosterone

Front 120

In the face of rising systemic BP, the myogenic mechanism will do what? Why?

Back 120

It will constrict the afferent arteriole and keep the glomerular volume and GFR steady or the same.

Front 121

What consists of the layers of the ureter wall?

Back 121

*Inside to Outside*
Lumen -> mucosa (transitional ET -> lamina propia) -> muscularis (longitudinal -> circular) -> serosa