Phys Ii: Renal Normal Physiology

Front 1

What are the two lyphatic systems in the kidney?

Back 1

1. Renal capsule and outer cortex
2. With the cardiovascular vessels

Front 2

What nerves innervate the renal system?

Back 2

Lesser splanchnic nerves to afferent/efferent by arterioles and proximal/distal tubules & glomerular cells.

Front 3

What do the lesser splanchnic nerves send afferent signals to? Efferent?

Back 3

1.afferent = GVA (pain) from capsule and hilum.
2. efferent = vasoconstriction and renin release.

Front 4

Where do things enter/ exit the kidney (blood vessels & nerves)?

Back 4

At the hilum

Front 5

What are the 8 major functions of the kidney?

Back 5

1. regulation of water and electrolyte balance
2. regulation of arterial bp
3. excretion of metabolic wastes
4. maintenance of proper plasma volume and osmolality
5. regulation of acid-base balance
6. endocrine: secretion of erythropoietin and renin
7. conversion of vitamin D into active form
8. Excretion of foreign compounds (drugs, food additives, etc)

Front 6

What is the structural and functional unit of the kidney?

Back 6

The nephron - also the smallest unit capable of urine formation.

Front 7

About how many nephrons make up one kidney?

Back 7

about 1 million

Front 8

What makes up a nephron?

Back 8

Specialized tubular structure and associated blood vessels.

Front 9

What type of cell makes up the entire renal tubule and collecting duct system?

Back 9

A single layer of epithelial cells.

Front 10

The afferent arteriole in bowman's capsule goes ____ the glomerulus and the efferent goes ___ the gomerulus.

Back 10

Afferent = toward
Efferent = away from

Front 11

Trace the flow of urine output from bowman's capsule to collecting duct.

Back 11

1. Glomerulus (capsule)
2. proximal convoluted tubule
3. descending loop of henle (thin loop)
4. ascending loop of henle (
5. distal convoluted tubule
6. collecting tubule/ duct

Front 12

Where is the macula densa located?

Back 12

It is a small segment of the distal convoluted tubule as it passes between the afferent and efferent arterioles of the glomerulus with specialized cells for sensitivity to osmolarity/ sodium concentration.

Front 13

Trace the flow of blood from the aorta to the inferior vena cava through the kidney.

Back 13

Aorta>renal artery> afferent arterioles > glomerulus > efferent arterioles > peritubular capillaries & vasa recta > renal venules > renal veins > inferior v.c.

Front 14

What blood vessels vascularize and feed the renal tissue itself?

Back 14

Peritubular capillaries.

Front 15

What are the two types of nephrons? Which are more common?

Back 15

1. Cortical (superficial) neprhons - most common 80%
2. Juxtamedullary nephrons

Front 16

Where are cortical nephrons?

Back 16

almost completely inthe cortex, and include short loop of henle, efferent arteriole branches into peritubular capillaries.

Front 17

Where are Juxtamedullary neprhons?

Back 17

Lie in cortex and medulla. Have a long loop of henle (reaches into the deep medulla), includes efferent arterioles that branch into peritubular capillaries AND vasa recta.

Front 18

What are the four basic renal processes?

Back 18

Glomerular filtration
Tubular reabsorption
Tubular secretion
Excretion

Front 19

What does glomerular filtration involve?

Back 19

Filtration of protein-free plasma from glomerulus into bowman's capsule. Filtrate then flows through tubules

Front 20

Wht does tubular reabsorption involve?

Back 20

selective movement of substances from tubular lumen into peritubular capillaries (vasa recta) (i.e. sodium, hormones, etc)

Front 21

What does tubular secretion involve?

Back 21

selective movement of non-filtered substances from peritubular capillaries into the tubular lumen.

Front 22

The vasa recta is the collective term for the ____.

Back 22

Kidney veins beginning with peritubular capillaries all the way to renal veins.

Front 23

The membrane of the glomerulus is ____ more permeable than that of other capillaries.

Back 23

400x

Front 24

What are the three layers of the glomeruluar capillary?

Back 24

1. endothelium (pores or fenestrae)
2. basement membrane (negatively charged glycoproteins)
3. epithelium = podocytes attached to basement membrane by foot processes that form filtration slits.

Front 25

What is the purpose of negatively charged glycoproteins in the Basement membrane of the glomerular capillary?

Back 25

They attract cations and repel anions (preventing proteinurea - loss of protein into the urine)

Front 26

What dos the macula densa do?

Back 26

Sense composition of blood to determine what needs to be secreted, retained, etc. Major component connecting circular system, lymph system, and endocrine system.

Front 27

What percent of cardiac blood flow do the kidneys receive? What percent proceeds to vasa recta?

Back 27

20%, most goes only to the cortex, only 1-2% goes to vasa recta

Front 28

About how much blood flows through the kidneys daily?

Back 28

1.25L/min = 1800Liters/ day

Front 29

What is Ohm's law? What does it mean?

Back 29

Q = P/R

Front 30

Hydrostatic pressure within the glomerular capillaries is about ___ _mmHg?

Back 30

55mmHg (Favors flitration)

Front 31

Hydrostatic pressure within bowman's capsule (backpressure) is about ____mmHg?

Back 31

15 mmHg

Front 32

Osmotic pressure within the glomerular capillaries (due to plasma proteins) is ____mmHg

Back 32

30mmHg

Front 33

How is net filtration pressure calculated?

Back 33

N= Ph - x - Pf
Ph = hydrostatic pressure of capillaries
x = osmotic pressure due to proteins
Pf = hydrostatic pressure of bowman's capsule
ex) 55-30-15 = 10mmHg

Front 34

In what ways could net filtration pressure be decreased?

Back 34

1. decreasing arterial pressure (a small effect)
2. increasing resistance of afferent arteriole (decrease glomerular hydrostatic pressure)
3. Decreasing resistance of efferent arteriole (decreases glomerular hydrostatic pressure)
4. increasing glomerular plasma colloid osmotic pressure

Front 35

What is GFR?

Back 35

Glomerular Filtration Rate - quantity of filtrate formed each minute in all nephrons of both kidneys. (index of kidney function)

Front 36

What are normal values for GFR?

Back 36

125mL/min or 180 L/day (males; range 90-140mL/min)
115mL/min or 160 L/day (females; range: 80-125mL/min)

Front 37

What is GFR directly proportional to?

Back 37

1. net filtration pressure
2. glomerular surface area
3. permeability of glomerular membrane (filtration coefficient, Kf)

Front 38

What is the formula to calculate GFR?

Back 38

GFR = Kf x net filtration pressure

Front 39

What factors decrease GFR?

Back 39

renal disease, diabetes, HTN, Urinary tract obstruction, decreased renal blood flow, increased plasma protein concentration, decreased angiotensin II, increased sympathetic tone

Front 40

Decreased arterial pressure has ____ effect on GFR due to ____.

Back 40

1. little
2. phenomenon of autoregulation

Front 41

What keeps renal plasma flow GFR constant despite changes in arterial BP (80-180mmHg)

Back 41

An automatic feedback mechanism.

Front 42

If no autoregulation, an 25mmHg increase in BP would cause____ in GFR that would produce _____ L of urine per day.

Back 42

1. a 25% increase
2. an additional 40-50L (holy moly!!!)

Front 43

The renal feedback system links NaCl sensed by ____ with control of _____ to adjust.

Back 43

1. macula densa
2. renal afferent arteriole

Front 44

What are the two components of the tubuloglomerular feedback mechanism in the juxtaglomerular apparatus?

Back 44

1. afferent arteriolar (decreased NaCl sensed by Macula densa decreases renal arteriolar blood flow )
2. efferent arteriolar (release of renin, angiontensin II increases renal efferent arteriolar blood flow)
together they can decrease filtration

Front 45

The nephron's vascular component called ______ also has ability to help maintain GFR by:

Back 45

myogenic mechanism
- inherent tendency of vascular smooth muscle to contract when stretched
- diameter of afferent arterioles changes to respond to changes in BP (vasodilation)

Front 46

_____ mediates the extrinsic control of GFR

Back 46

- sympathetic nervous system.

Front 47

Increased sympathetic activity.

Back 47

- decreases GFR and renal blood flow by causing constriction of renal arterioles and decreasing Kf

Front 48

Increased circulating levels of NE and E - released by the adrenal medulla result in.

Back 48

constrict afferent and efferent arterioles causing reduction in GFR and renal blood flow

Front 49

ncreased levels of endothelin (a peptide released from damaged endothelial cells) results in

Back 49

causes constriction of arterioles and reduction of GFR and renal blood flow

Front 50

Increased secretion of angiotension II

Back 50

causes preferential constricton of efferent arterioles which raises glomeruluar hydrostatic presure and reduces renal blood flow, increasing GFR

Front 51

Endothelial-derived nitric oxide (autocrine released from blood vessels)

Back 51

decreases renal vascular resistance and increases GFR

Front 52

Increased renal prostaglandins

Back 52

- especially PGE2 and PGI2, cause decreased renal vascular resistance, increased renal blood flow and increased GFR. Conversely blockade of prostaglandins synthesis with nonsteroid anti-inflammatory drugs (e.g. aspirin) tends to reduce renal blood flow and GFR

Front 53

Autoregulation of GFR and renal blood flow -

Back 53

occurs through mechanisms that are intrinsic to the kidney. The autoregulatory mechanisms keep renal blood flow and GFR relatively constant during variations in renal artery pressure been 80 and 100 mm Hg in normal kidneys

Front 54

Tubular reabsorption is ____ selective. It involves ___

Back 54

1. highly selective
2. excretion of excess amounts of essential materials and concentration of waste products

Front 55

What 5 barriers must a substance go through to be reabsorbed in the tubule system?

Back 55

1. cross the luminal membrane of the tubular cell
2. pass through cytosol from one side of tubular cell to the other.
3. Transverse the basolateral membrane of the tubular cell to enter the ECF (extracellular fluid)
4. Diffuse through ECF
5. Penetrate the capillary wall to enter the plasma

Front 56

What are the two types of tubular reabsorption?

Back 56

1 passive transport
2. active transport

Front 57

What occurs during passive tubular reabsorption?

Back 57

no energy is required. Movement of water by osmosis

Front 58

What occurs during active tubular reabsorption?

Back 58

requires energy. Involves teh Na/K/ATPase mechanism in the basolateral membrane

Front 59

What is the largest use (80%) of kidney energy used to transport?

Back 59

(80%) of kidney energy requirement is used for sodium transport. (ATP pumps K into the cell and Na out... this means more Na diffuses from tubule, along with water)

Front 60

What amount of the filtrate is reabsorbed in the Proximal Convoluted Tubule by active and passive transport?

Back 60

65% - includes 100% of filtered glucose, proteins, or amino acids

Front 61

What does the reabsorption of filtrate heavily depend on?

Back 61

Indirect or direct ACTIVE reabsorption of Na+ (67% of Na+ is reabsorbed in PCT)

Front 62

Of the Na+ filtered, what percent is reabsorbed, and in what areas of the system?

Back 62

1. 99.5% reabsorbed
2. 67% PCT, 25% Loop of Henle, ~8% in DCT and CT.

Front 63

What are the three functional parts of the loop of Henle?

Back 63

descending thin
ascending thin
ascending thick (impermeable to water)

Front 64

What substances are reabsorbed in the PCT?

Back 64

2/3 water and electrolytes, all glucose, amino acids, and vitamins

Front 65

What occurs in the descending loop of henle?

Back 65

reabsorption of water

Front 66

What occurs in the ascending loop of henle?

Back 66

active reabsorption of Na, K, Cl in order to produce a hypoosmotic filtrate and high interstitial osmolality

Front 67

What occurs in the distal convoluted tubule?

Back 67

Reabsorption of Na, Cl, water, and urea. Also the site of the macula densa (regulation of GFR), and secretion of H and K.

Front 68

What occurs in the collecting tubule?

Back 68

Reabsorption of water under influence of ADH, secretion of H and K

Front 69

What type of tissue lines the descending loop of henle?

Back 69

Simple squamous epithelium

Front 70

In the descending loop of henle, reabsorption of water occurs _____ due to osmotic forces

Back 70

Passively

Front 71

What type of tissue is in the ascending loop of henle?

Back 71

Simple cuboidal epithelium

Front 72

______ transport of Na at the basolateral border, followed by Cl ions following the Na, occurs in the ____.

Back 72

Active
Ascending loop of henle

Front 73

In the ascending loop of henle, the cells are _______ to water.

Back 73

Impermeable

Front 74

In the DCT and CT, reabsorption is ____ and controlled by ____

Back 74

variable
hormones

Front 75

Reabsorption of Na in the DCT and CT is controlled by ______... follwed by Cl passively

Back 75

Aldosterone

Front 76

Reabsorption of water in the DCT and CT is controlled by _____.

Back 76

Antidiuretic horomone (ADH)

Front 77

What is the idea of a countercurrent multiplier as found in the loop of henle?

Back 77

basically, the ascending loop actively pumps NaCl into interstitial space near descending loop. As a result, water osmoses passively out of the descending loop. (ascending impermeable to water), therefore the filtrate is more concentrated because NaCl is actively pumped out, while interstium remains highly concentrated.

Front 78

What is tubular secretion?

Back 78

Movement of substances from the peritubular capillaries into the renal tubule. (anything from the tubular system that is not reabsorbed)

Front 79

Tubular secretion is the major excretion pathway for ____, ___, and ____ and ____ (many are foreign to the body)

Back 79

H, K, organic anions, cations

Front 80

Renal H+ secretion is important in regulation of ______

Back 80

acid-base balance

Front 81

Where is H+ added to the urinary filtrate?

Back 81

PCT, DCT, and collecting duct.

Front 82

Amount of H+ secretion into the tubular system depends on ____

Back 82

acidity of body fluids

Front 83

K+ is _____reabsorbed in the ___ and ____ secreted in the ___ and ___.

Back 83

1. actively reabsorbed in the PCT
2. actively secreted in teh DCT and CT

Front 84

K+ ion secretion is coupled to _____ reabsorption of ____ via the ______.

Back 84

1. Na+
2. NA+/K+ ATPase pumps

Front 85

Increased aldosterone presence promotes increased ____ reabsorption and ____ secretion.

Back 85

Na+ reabsorption,
K+ secretion

Front 86

Under normal conditions (GFR = 125mL/min), what amount of urine is excreted/ min?

Back 86

1mL

Front 87

Average excretion is ____L/day

Back 87

1.5 L/day of urine

Front 88

The abiity to radically change the final concentration of urine is ____ controled by ___, ___ and ___

Back 88

1. hormonally
2. aldosterone, ADH, and ANP

Front 89

The typical pH of urine is ____ with a specific gravity of ___.

Back 89

1. pH=6
2. SG= 1.010 -1.025

Front 90

The composition of urine is ____ water.

Back 90

95%

Front 91

What electrolytes are found in urine?

Back 91

Na+, K+. Cl-, Ca+, Mg+, traces of PO4, SO4

Front 92

Name some abnormal constituents of urine.

Back 92

albumin, glucose, RBCs, WBCs, stones

Front 93

Filling of the bladder activates ____ receptors. Stimulation of ___ causes the bladder to contract.

Back 93

1. stretch
2. parasympathetic fibers

Front 94

Stretch receptors from the bladder send impulses to the ____.

Back 94

cerebral cortex