Jackson 5

Question 1

. Other renal functions include:

Answer 1

Gluconeogenesis

Production of hormones

Question 2

Kidney produces

Answer 2

erythropoietin – acts in the bone marrow to stimulate synthesis of new erythrocytes

renin – part of renin-angiotensin-aldosterone cascade to regulate blood pressure

1,25-dihydroxyvitamin D – regulate calcium absorption

Question 3

renin –

Answer 3

part of renin-angiotensin-aldosterone cascade to regulate blood pressure

Question 4

1,25-dihydroxyvitamin D –

Answer 4

regulate calcium absorption

Question 5

The actual proportion of the total body water that the kidney “sees” and process is

Answer 5

very small. However, changes in the one, small compartment affected by kidney function can ultimately affect the other compartments.

Question 6

ESRD patients have a reduced ability to

Answer 6

eliminate nitrogenous wastes (urea) and excess nitrogen is converted to ammonium.

Question 7

ESRD patients;

The excess ammonium has

Answer 7

direct effects on health – the blood is alkalized which leads to an increased pH in the oral cavity.

Question 8

Manifestations of renal disease on oral health include:

Answer 8

ammonia breath –

gingival enlargement –

xerostomia –

tooth problems
-premature loss

• narrowing pulp chambers
• necrosis beneath fillings or crowns

Question 9

Contraindications for ESRD patients:

Answer 9

nephrotoxic drugs such as tetracycline, acyclovir, aspirin, NSAIDs

increased susceptibility to bleeding due to destruction of platelets

Question 10

in the renal medulla – there are

Answer 10

portions of nephron tubule involved with concentration and collection of urine

Question 11

Each kidney contains

Answer 11

~1.2 x 106 nephrons.

Question 12

A nephron includes a cluster of

Answer 12

capillaries and a long, hollow tube with a wall that is one cell layer thick.

Question 13

Parts of a nephron

Answer 13

renal corpuscle = glomerulus + capsule

proximal (convoluted) tubule

loop of Henle

distal (convoluted) tubule

collecting duct – shared by several nephrons

Question 14

The position of a nephron with respect to the

Answer 14

cortical and medullary regions of the kidney can vary somewhat. There are two types of nephrons that differ in the position of the renal corpuscle and the length of the medullary tubules
superficial or cortical nephrons -

juxtamedullary nephrons -

Question 15

Regulating blood composition involves three renal processes

Answer 15

Filtration
Secretion
Reabsorption

Question 16

1. filtration – solutes (and the water they are dissolved in) pass from the

Answer 16

blood into the tubular fluid in the renal capsule (Bowman’s space)

Question 17

filtration occurs in the

Answer 17

glomerular capillaries; 15-20% of plasma entering glomerulus is filtered

Question 18

blood leaving the glomerular capillaries then flows into

Answer 18

peritubular capillaries (vasa recta)

Question 19

1. secretion – substances are transported from the blood in the

Answer 19

peritubular capillaries into the tubular fluid

Question 20

1. reabsorption – substances are transported from the tubular fluid into the blood in the

Answer 20

peritubular capillaries

Question 21

Re: renal corpuscle =

Answer 21

glomerulus + renal capsule

Question 22

A glomerulus is a dense capillary bed where filtration occurs
surrounded by

Answer 22

renal capsule (or Bowman’s capsule) which collects the filtrate from the blood entering via the afferent arterioles

Question 23

filtered blood leaves via

Answer 23

efferent arterioles and flows into peritubular capillaries

Question 24

Blood flow through the glomerulus is regulated by several mechanisms

Answer 24

smooth muscle contraction in afferent or efferent arterioles

response of the juxtaglomerular apparatus (JGA) located at the intersection of the macula densa of distal tubule with afferent and efferent arterioles –

sympathetic nervous system –

Question 25

juxtaglomerular apparatus (JGA) secretes the hormone

Answer 25

renin which regulates systemic blood pressure, and, therefore, glomerular blood flow

Question 26

Proximal convoluted tubule
The proximal tubule drains the renal capsule
reabsorbs

Answer 26

2/3 of flitered salt and water

reabsorbs all filtered glucose and amino acids

some diurectics will act here

Question 27

Loop of Henle

Loop of Henle can be divided into three limbs or segments

Answer 27

thin descending limb

thin ascending limb

thick ascending limb (TAL)

Question 28

The loop is the site of

Answer 28

countercurrent multiplication needed to produce concentrated urine, but the loop itself produces a dilute filtrate.

Question 29

Very powerful diuretics work in the

Answer 29

Loop of Henle.

Question 30

Distal convoluted tubule

The distal tubule drains the

Answer 30

loop of Henle
continued reabsorption of solutes –

regulation of calcium –

site of action for some diuretics

Question 31

Collecting duct

Collecting duct – collects fluid from

Answer 31

multiple nephrons

Question 32

Collecting duct

extends from

Answer 32

cortex through the medulla

Question 33

Collecting duct

regulates

Answer 33

sodium, potassium, and water

some diuretics act here

Question 34

Renal clearance is the

Answer 34

rate of excretion of a solute through the kidney, expressed as amount per unit time.

=

Question 35

renal clearance represents the

Answer 35

volume of plasma from which all of a particular substance is removed to the urine (i.e. cleared), e.g. 100 ml/min

clinically important concept for monitoring renal function

Question 36

Glomerular filtration rate is the amount of blood filtered by the

Answer 36

kidney, expessed as volume per unit time.

Question 37

Renal clearance can be used to measure glomerular filtration rate (GFR) based on three criteria

Answer 37

1. the substance must be freely filtered in the glomerulus
2. the substance is not secreted
3. the substance is not reabsorbed

Question 38

in a normal kidney, GFR (from all nephrons) is

Answer 38

125 ml/min or 180 L/day in females; 90-140 ml/min in males

Question 39

Inulin and creatinine are substances that can be used to measure

Answer 39

renal clearance

Question 40

inulin –

Answer 40

small polysaccharide; freely filtered and not secreted or absorbed

Question 41

creatinine –

Answer 41

product of muscle metabolism; freely filtered, not reasbsorbed, almost no secretion; normal creatinine levels < 1+ 0.5 mg/dl; if > 10 → requires dialysis

Question 42

Glomerular capillaries are

Answer 42

fenestrated;

Question 43

podocytes (cells) around the

Answer 43

capillaries form filtration slits

Question 44

filtrate is

Answer 44

acellular and essentially protein-free

Question 45

————————- are freely filtered

Answer 45

glucose, salts, and amino acids

Question 46

size is a factor:

Answer 46

< 20 Ǻ freely filtered, > 42 Ǻ not filtered

Question 47

charge is also a factor

Answer 47

basal lamina (basement membrane) is negatively charged so filtration of moderately-sized, negatively-charged solutes is limited

Question 48

Filtration occurs due to

Answer 48

pressure differences between the blood in the capillaries and the fluid in the capsule (Starling forces).

Question 49

Pressure comes from two sources:

Answer 49

hydrostatic pressure = pressure due to fluid
P in capillaries > P in capsule fluid

oncotic pressure (π) – pressure due to solutes in fluid (including those not dissolved)
π in capillaries > π in capsule fluid

Question 50

Net filtration pressure favors filtration from

Answer 50

blood into the capsule fluid

GFR ∞ (PGC – PBS) – (πGC – πBS) note that πBS = 0

Question 51

GFR is affected by

Answer 51

blood flow into and out of the glomerulus, and P gradient is critical to maintain filtration

Question 52

Despite changes in systemic blood pressure, renal blood flow (RBF) remains

Answer 52

fairly constant

because RBF remains constant, GFR remains constant

Question 53

Autoregulation involves intrinsic mechanisms that adjust bloodflow through the glomerulus; it is achieved by two primary mechanisms:

Answer 53

1. myogenic mechanism – vascular smooth muscle tends to contract when it is stretched, and relax when not stretched

constriction or dilation of smooth muscle in afferent or efferent arterioles has contrasting effects on RBF

2. tubuloglomerular feedback – feedback from the JGA adjusts afferent arteriole diameter and, thus, GFR

↑ GFR à ↑ NaCl in tubular fluid à ↑ NaCl at macula
densa à ↑ resistance in afferent arterioles à ↓ GFR

Question 54

myogenic mechanism –

Answer 54

vascular smooth muscle tends to contract when it is stretched, and relax when not stretched

Question 55

2. tubuloglomerular feedback –

Answer 55

feedback from the JGA adjusts afferent arteriole diameter and, thus, GFR

Question 56

Also have extrinsic factors regulating RBF and GFR; some will be discussed in further detail in subsequent lectures

Answer 56

diet –

dehydration or hemorrhage –

sympathetic nervous system –

angiotensin II, aldosterone, and natriuretic peptide -