Download MBBS Physiology Presentations 5 Tubular Processes Lecture Notes

--- Content provided by FirstRanker.com ---

To understand

Terminology to know processes of handling tubular fluid ?

Renal Tubular Reabsorption or Secretion- Transcellular & paracellular pathway

--- Content provided by FirstRanker.com ---

Tubular Cells ?Tight Junctions

To calculate secretion or reabsorption rate of any solute

--- Content provided by‌ FirstRanker.com ---

Nephron Terminology

Various transport mechanisms in proximal convoluted tubules

Glomerulo-tubular balance, and it's physiologic importance

--- Content provided by‍ FirstRanker.com ---

Glucose transport maximum
Terminology to know processes of handling tubular fluid

Tubular Reabsorption or Secretion in Renal Tubules

--- Content provided by​ FirstRanker.com ---

PTCp

1. Reabsorption:

--- Content provided by FirstRanker.com ---

1

2. Secretion:

TF

--- Content provided by​ FirstRanker.com ---

2.
Tubular Cells ?Tight Junctions

PTCp

--- Content provided by⁠ FirstRanker.com ---

Tight junctions

1

--- Content provided by⁠ FirstRanker.com ---

Tight junctions ? claudins and occludins.

TF

2.

--- Content provided by⁠ FirstRanker.com ---

Tubular Reabsorption/Secretion - Routes/Pathways

PTCp

--- Content provided by⁠ FirstRanker.com ---

Transcel ular pathway:

1

Paracellular pathway:

--- Content provided by​ FirstRanker.com ---

TF

2.
Pressures favoring reabsorption by bulk flow into peritubular Cps

--- Content provided by FirstRanker.com ---

bulk

flow

--- Content provided by‍ FirstRanker.com ---

GENERAL PRINCIPLES OF MEMBRANE TRANSPORT ? across cell membranes

Passive transport of substances (without expenditure of energy):

Active transport of subtances (with the expenditure of energy):

--- Content provided by​ FirstRanker.com ---

Solvent drag-
Nephron : Tubular Segments

Three major segments:

--- Content provided by‍ FirstRanker.com ---

These segments determine the composition & volume of the urine by the

Reabsorption and Secretion Rates of substances in renal tubules
Nephron Terminology

--- Content provided by⁠ FirstRanker.com ---

TF/P ratio

2. TF/Pinulin

--- Content provided by FirstRanker.com ---

3. [TF/P]x /[TF/P]inulin ratio

Exercise questions
Segment - Proximal Convoluted Tubule ?

--- Content provided by FirstRanker.com ---

Tubule Characteristics --TF handling as per Permeability

+ADH/ - ADH

AQP1

--- Content provided by‌ FirstRanker.com ---

Transport mechanisms of different solutes of TF ? PxCT
First half of Px CT

Active NaCl Transport

--- Content provided by FirstRanker.com ---

H2O

NaCl

--- Content provided by⁠ FirstRanker.com ---

Urea

++

Early Part of Proximal Convoluted Tubule PxCT

--- Content provided by‌ FirstRanker.com ---

++

+

--- Content provided by‌ FirstRanker.com ---

+

H2O

Na+ Reabsorption

--- Content provided by FirstRanker.com ---

Active NaCl Transport

H2O

NaCl

--- Content provided by‍ FirstRanker.com ---

Urea

++

--- Content provided by FirstRanker.com ---

Early Part of Proximal Convoluted Tubule PxCT

++

+

--- Content provided by FirstRanker.com ---

+

H+ secretion and

--- Content provided by‌ FirstRanker.com ---

H2O

HCO3-Reabsorption

Early Part of Proximal Convoluted Tubule

--- Content provided by⁠ FirstRanker.com ---

Active NaCl Transport

H2O

--- Content provided by​ FirstRanker.com ---

NaCl

Urea

PxCT

--- Content provided by⁠ FirstRanker.com ---

++

++

--- Content provided by FirstRanker.com ---

+

+

Glucose

--- Content provided by FirstRanker.com ---

reabsorption
Applied-

Mutations in the GLUT2 gene

--- Content provided by‌ FirstRanker.com ---

Active NaCl Transport

H2O

--- Content provided by⁠ FirstRanker.com ---

NaCl

Urea

++

--- Content provided by‍ FirstRanker.com ---

Early Part of Proximal Convoluted Tubule PxCT

++

--- Content provided by FirstRanker.com ---

+

+

Ca++, Mg++, K+ , Urea

--- Content provided by⁠ FirstRanker.com ---

Paracellular

H

--- Content provided by‍ FirstRanker.com ---

reabsorption

2O
Second half of Px CT

--- Content provided by⁠ FirstRanker.com ---

Active NaCl Transport

H2O

NaCl

--- Content provided by​ FirstRanker.com ---

Urea

++

--- Content provided by FirstRanker.com ---

Second half of PxCT

PxCT

++

--- Content provided by‌ FirstRanker.com ---

+

+

--- Content provided by⁠ FirstRanker.com ---

Na+ and Cl-

reabsorption
Active NaCl Transport

--- Content provided by⁠ FirstRanker.com ---

H2O

NaCl

Urea

--- Content provided by​ FirstRanker.com ---

++

Second half of PxCT

--- Content provided by‍ FirstRanker.com ---

PxCT

++

+

--- Content provided by FirstRanker.com ---

+

(Mechanism: Na+H+ - Cl-Anion Antiporters)

--- Content provided by‍ FirstRanker.com ---

Second half of PxCT

Na+-glucose symporter (SGLT1)
Second half of Proximal Convoluted Tubule

--- Content provided by‌ FirstRanker.com ---

Water reabsorption

Urea reabsorption

Pinocytosis--An Active Transport Mechanism for Reabsorption of

--- Content provided by‍ FirstRanker.com ---

large molecules such as Proteins in PxT
Summary of handling of % of water & solutes ? Px CT

Summary of Transporters in Px CT

--- Content provided by‌ FirstRanker.com ---

Osmolality of TF Leaving PxCT

Clinical Relevance ? Acute Tubular Necrosis (ATN )
Transport Maximum (Tm)

--- Content provided by‍ FirstRanker.com ---

Blood glucose level and corresponding Glucose tubular load

This glucose blood concentration (200 mg/dl) and the filtered load of 250 mg/min are

termed as the renal threshold for glucose.

--- Content provided by FirstRanker.com ---

Cause of difference of TmG and Renal threshold for glucose

Phenomenon of SPLAY

ideal

--- Content provided by⁠ FirstRanker.com ---

(or glucose amount filtered)

Regulation of Tubular processes

--- Content provided by‌ FirstRanker.com ---

Because it is essential to maintain a precise balance between tubular

reabsorption and glomerular filtration, there are multiple nervous,

hormonal, and local control mechanisms that regulate tubular

--- Content provided by‌ FirstRanker.com ---

reabsorption.
Glomerulo-tubular Balance

Glomerulo-tubular balance - Mechanism

--- Content provided by‌ FirstRanker.com ---

Tubuloglomerular feedback vs Glomerulo-tubular balance

N
aC
l

--- Content provided by​ FirstRanker.com ---

Self Assessment

Percentage of filtered urea, reabsorbed by Px CT is about :

--- Content provided by‌ FirstRanker.com ---

1. 00-25
2. 50 -65

3. 70-95

--- Content provided by FirstRanker.com ---

4. 80-100

If there is increased load of NaCl and water, what wil happen in Px CT

1) There wil be an increase in NaCl and water reabsorption.

--- Content provided by‌ FirstRanker.com ---

2) There wil be a decrease in NaCl and water reabsorption.

3) There wil be an increase in NaCl but water reabsorption wil decrease
4) There wil not be any change

--- Content provided by‌ FirstRanker.com ---

Water channel present in proximal convoluted tubule is:

1. Aquaporin 1
2. Aquaporin 2

--- Content provided by FirstRanker.com ---

3. Aquaporin 3

4. Aquaporin 4

At the leaving end of PxCT, percentage of filtered solute

--- Content provided by FirstRanker.com ---

and water is approximately:

1) 35% solute and 35% water

2) 45% solute and 45% water

--- Content provided by FirstRanker.com ---

3) 35% solute and 45% water
4) 45% solute and 35% water
Thank you