Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Renal Week 1 > Lecture 2: An Overview of the Kidney and its Logic > Flashcards

Lecture 2: An Overview of the Kidney and its Logic Flashcards

1
Q

What are the functions of the kidney?

A
  1. Elimination of Nitrogenous Waste Products
  2. Regulation of Acid-Base Balance
  3. Regulation of Blood Pressure
  4. Regulation of Red Blood Cell Volume (total RBCs in body due to EPO)
  5. Regulation of Calcium (bone) metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is filtration pressure?

A

The pressure that allows fluid to enter the glomerular capillaries
Determined by the following equation:
Filtration Pressure (FP) = GCP – COP –CP
Usually 7mmHg

GCP = Glomerular capillary pressure
COP = Colloid Osmotic Pressure
CP = Capsule Pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the forces that favor filtration?

A

Glomerular capillary pressure

also a capsule osmotic pressure that is mentioned later by Berns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the forces oppose filtration?

A
  1. Colloid Osmotic Pressure

2. Capsule Pressure aka Hydrostatic Pressure in Bowman’s space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is oncotic?

A

Oncotic pressure = colloid osmotic pressure
A form of osmotic pressure exerted by proteins in a blood vessel’s plasma
Oncotic pressure increases as more fluid gets filtered into the glomerular capillaries
-thus increase in protein concentration at end of glomerular capillary means there is a decrease in filtration rate at this area
-this occurs at the Efferent arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How much fluid is filtered by both kidneys combined?

A

180 liters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the ultimate role of glomerular filtration?

A

Elimination of nitrogenous waste products via
i. urea
ii. uric acid
Utilization of NH3 in urea cycle is key to elimination of the metabolic end product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the toxins that the kidney secretes?

A
  1. urea

2. uric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where does most of the regulation in kidney occur?

A

Afferent arteriole
Adjustments in the afferent arteriole will autoregulate renal blood flow and GFR
Kidney tries to keep GFR, filtered sodium load and intrarenal pressures stable
Contains
i. Smooth muscle cell
ii. JGA cells
iii. Sympathetic innervation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the function of the juxtaglomerular apparatus?

A

Get signals from glomerulus about amount of renal blood flow as well as the electrolyte composition
Located on afferent arteriole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the proximal tubule?

A

A “leaky epithelium” that reabsorbs high volumes of fluids and its constituents
Small transepithelial electrical potential
Maintains very small gradients
Has high WATER PERMEABILITY
Transports solute actively and water passively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the main driving force of transport

For the proximal tubule?

A

Gradient for sodium from lumen to cell interior
(140 mEq/L to 20 mEq/L)
Mediated through Na/K ATPase on basolateral membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does water get transported into the proximal tubule?

A

In two ways
1. Through the cell (and exits out into restricted basal spaces that are slightly hyperosmotic…#2 on picture below)
2. Through tight junctions (#1 because) because Na/K ATPase establishes hyperosmotic solution in the LATERAL INTERCELLULAR SPACE
So the two spaces are the restricted basal spaces and the lateral intercellular spaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the characteristics of distal nephron transport (eg DCT)?

A

Has a “tight” epithelium
Under hormonal control
Can establish steep gradients with high electrochemical potential
Since it is hormonally regulated, this is where the steady state balance is created

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is ENaC regulated by?

A

Aldosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why does Na/K ATPase utilize 50% of all cell energy?

A

Because it is the engine for regulation of cell volume

17
Q

What is amiloride?

A

A potassium sparing diuretic
Directly blocks the ENaC in the DCTs, connecting tubules and collecting ducts
Potassium channel still works so that’s why it is “potassium sparing”

18
Q

Where are aquaporins located?

A
  1. Descending LoH
  2. DCT
  3. Collecting duct
    Other places in body, such as brain
    Other places in kidney that is not mentioned
    Here
    There are 13 types of aquaporins
19
Q

What is the MoA of ADH?

A

ADH activates a G-protein coupled receptor
Increases cAMP
Increases Protein Kinase A
Inserts aquaporins into apical membrane

20
Q

What is the key principle of the organization of renal tubule?

A

Proximal tubule = bulk reabsorptive system to maintain normal homeostasis
Distal nephron = fine tuning of the body’s content of fluid/minerals
-under control of endocrine systems such as ADH

21
Q

Where does PCT end?

A

At the pars recta (straight part of the PCT)

Right before thin descending LoH

22
Q

How does kidney maintain steady state despite the increasing concentration of solute in the kidney tubules?

A

Can alter rates and direction of transport
Does so via Synthesis or Destruction of epithelial transporters and changes in morphology
Modulated by hormones

23
Q

What is the normal sodium urinary excretion?

A

It “depends”
If there is a lot of sodium, you will need to excrete a lot
If there is not a lot of sodium, you won’t excrete as much

24
Q

What is relationship between

Excretion and intake? (Lecture takehome point)

A

Excretion must always be related to intake. If it doesn’t, then you have disease

25
Q

How does kidney regulate blood pressure?

A 
Can increase circulating volume
Can increase vascular resistance
Both will increase blood pressure if BP is low
Also through the RAAS 
	-renin, angiotensin II, aldosterone
26
Q

What is Liddle’s Syndrome?

A

ENaC channel is “stuck” open
Inappropriate high rates of sedum uptake in distal nephron = HTN
Low aldosterone levels because there is defect in ENaC
Key: An example of HTN due to excess extracellular fluid volume

27
Q

How does the kidney contribute to acid-base balance?

A

By regulating the amount of buffer base in solution (HCO3-)
pH of 6.8 = coma and death
pH of 7.8 = cramps and death
7.4 = normal

28
Q

What are the sources of H+?

A
  1. Cell metabolism (CO2)
  2. Food products
  3. Medications
  4. Metabolic intermediate byproducts
29
Q

How do the kidneys respond to acidosis?

A

Retains bicarbonate ions

Eliminates H+

30
Q

How do kidneys respond to alkalosis?

A

Eliminates bicarb

Retains H+

31
Q

How does Kidney regulate vitamin D synthesis?

A

Kidney is the main site of formation of 1,25 dihydroxy Vitamine D
1,a hydroxylase is located in the kidney
25,OH-D3 is converted to 1,25 dihydroxy vitamin D due to the actions of 1,a hydroxylase

32
Q

How does kidney regulate red cell mass?

A

Through the production of EPO

Oxygen sensor will dictate production rate of EPO

Renal Week 1 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions