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Secondary Active Transport

By: HWC, Views: 8276

Energy stored (in a hydrogen or sodium concentration gradient) is used to drive other substances against their own concentration gradients Secondary active transport, is transport of molecules across the cell membrane utilizing energy in other forms than ATP. In many cells, antiporters mov...

Resting membrane potential - electrical polarity and maintenance requirements

By: HWC, Views: 7480

• A resting membrane potential exists when there is a buildup of: 1. positive ions outside the membrane. 2. negative ions inside the membrane. • Membranes with opposing charges are said to be polarized. • The difference in charge applies only to the small distance across the membran...

Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 7964

• Tubular cells of the proximal convoluted tubule and collecting tubules can alter filtrate pH and therefore blood pH. • These cells can affect blood pH with two coupled mechanisms: • Reabsorption of bicarbonate ions. • Secretion of hydrogen ions. • The reabsorption of bicarbonate...

The Nerve Impulse

By: Administrator, Views: 12736

The action potential explained.

Angiotensin II - kidneys, adrenal glands and dehydration

By: HWC, Views: 7863

• Angiontensin II targets cells in the proximal convoluted tubule of the nephron. ■ The reabsorption of Na+ and Cl- ions sets up an osmotic gradient favoring the retention of water. • Decreases urine production and increases blood volume and pressure. • Angiontensin II targets zon...

Chemical Buffers - protein buffer, phosphate buffer system and bicarbonate buffer system

By: HWC, Views: 7970

• There are a variety of chemicals in body fluids that prevent the fluids from undergoing large changes in. • These chemicals buffer or regulate fluctuations in H+ concentration. • Chemical buffers: • Bind to H+ ions when there are too many in a solution so pH remains normal. •...

What are Strong & Weak Acids and How they're different?

By: HWC, Views: 6543

Let's consider the changes that take place when hydrogen chloride, HCI, is added to water. You will need to recognize space-filling models of HCI molecules, hydronium ions (H30+), chloride ions (C11, and water molecules (H20). They are shown at the right. When HC1 molecules dissolve in water, ...

Methods of carbon dioxide transport - carbaminohemoglobin and bicarbonate ions

By: HWC, Views: 7794

• Carbon dioxide is transported three ways: • As bicarbonate ions in the plasma. • Bound to hemoglobin. • As a dissolved gas in the plasma. • A small percent of carbon dioxide is transported as a dissolved gas. • Some of the carbon dioxide is bound to hemoglobin, in the fo...

Medullary osmotic gradient: countercurrent multiplier, urea recycling & vasa recta countercurrent exchange

By: HWC, Views: 8447

▪ The primary cause of the medullary osmotic gradient is the active transport of solutes. • In the ascending limb of the loop, active transport of Na+ ions drives passive reabsorption of Cl- ions. • Addition of these ions to the interstitial fluid of the medulla increases its osmolarity...