ACTIVE TRANSPORT

INTRODUCTION

INTRODUCTION

oDirect passage through membrane

oPassage through channels/carriers

CATEGORIES OF TRANSPORT PROCESSES

I. PASSIVE TRANSPOT – Simple diffusion, Facilitated diffusion, Osmosis, Filtration, Bulk flow & Solvent drag

II. ACTIVE TRANSPORT – Primary & Secondary VESICULAR TRANSPORT – Endocytosis, Exocytosis & Transcytosis

III. TRANSPORT ACROSS EPITHELIA – Trans cellular & Para cellular

ULTRAFILTRATION

ACTIVE TRANSPOT Uphill transport

Utilizes metabolic energy

Exhibits saturation kinetics

TYPES1. Primary Active Transport2. Secondary Active Transport

PRIMARY ACTIVE TRANSPORT

• Directly uses metabolic energy for the transport process

ION TRANSPORTING ATPases : P-type ATPases / E1-E2 ATPases

V-type ATPases

F-type ATPases

TYPES OF ATPases & THEIR LOCATION

Na-K ATPase

OPERATION OF Na-K PUMP

REGULATION OF Na-K ATPase ACTIVITY

INHIBITORS :-Dopamine- Temperature- Concentration of ions- Metabolic poisons- Hypoxia- Ouabain & related cardiac glycosides

REGULATION OF Na-K ATPase ACTIVITY

ACTIVATORS / PROMOTORS:- Thyroid hormones- Aldosterone- Insulin- cAMP, DAG

FUNCTIONS OF Na-K ATPase

CaATPase: PMCASERCAsH-K ATPase:Proton pump in Parietal cellsAcidification of urine

H ATPase:V-type ATPase in lysosomes & ERF-type ATPase in Inner Mitochondrial

membrane

ABC TransportersMDR1CFTR

SECONDARY ACTIVE TRANSPORT

1. CO-TRANSPORTERS/SYMPORTERS- Move both driving solute & driven solute in

same direction

Na/glucose cotransporter – SGLT1 to 3

Na/aminoacid cotransporter

Na/K/Cl cotransporter (NKCC)

Na/Cl cotransporter (NCC)

K/Cl cotransporter (KCC1 to 4)

H-driven cotransporters - H/oligopeptide cotransporter

- H/AA cotransporter - DMT1

2. EXCHANGERS / ANTIPORTERS

• Move driving solute in one direction & driven solute in opposite direction

2. EXCHANGERS / ANTIPORTERS

• Move driving solute in one direction & driven solute in opposite direction

Na-Ca exchanger (NCX) Na-H exchanger (NHE)

Na-driven Cl-HCo3 exchanger

Cl-HCo3 exchanger / Anion exchanger

Other Anion exchangers• SAT – Sulphate Anion Transporter• OATP – Organic anion transporter protein• PGT – Prostaglandin transporter• ROAT – Renal organic anion transporter• Cl-formate exchanger• Cl-oxalate exchanger

APPLIED PHYSIOLOGY Oral Rehydration Therapy Proton Pump Inhibitors Loop diureticsThiazide diuretics Cardiac Glycosides Drug Resistance in Cancer Cells Cystic Fibrosis

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