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Secondary Active Transport

By: HWC, Views: 7166

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...

Bone Growth and Remodeling

By: HWC, Views: 6940

• After birth, bones grow in thickness and length. • Bones grow in diameter via appositional growth at the periosteum. • Epiphyseal plates enable lengthwise growth of long bones, such as the humerus, by interstitial growth. • Bone remodeling accommodates changing needs. • While th...

Normal and abnormal blood pH

By: HWC, Views: 6717

• Dissociation of the chemical substances in the body fluids can result in the production of free hydrogen ions. • The pH scale is used to measure the concentration of hydrogen ions in solution. • Normal blood pH values vary around 7.4. • When hydrogen ion concentration increases, t...

Simple Diffusion - Ion transport

By: HWC, Views: 6705

In the process of diffusion, a substance tends to move from an area of high concentration to an area of low concentration until its concentration becomes equal throughout a space. Ions must diffuse through membrane pores or gated channels. Pores are always open. More pores allow more ions...

Simple Diffusion - gases and nonpolar compounds transport

By: HWC, Views: 6969

Gases and some molecules can diffuse through the phospholipid bilayer because they are small or non-polar. Oxygen gas. Carbon dioxide gas. Lipid based hormones. Plasma membranes are selectively permeable: The lipid bilayer is always permeable to small, nonpolar, uncharged molecules ...

Acid-base imbalances - compensation of metabolic acidosis and alkalosis

By: HWC, Views: 6908

1. Metabolic acidosis: • Few HC03- ions are present so blood pH becomes acidic. • Compensation is increased respiratory rate and more CO2 is removed from the blood. • Blood pH returns to normal. 2. Metabolic alkalosis: • Many HC03- ions are present so blood pH becomes alkaline...

Acid-base imbalances - compensation of respiratory acidosis and alkalosis

By: HWC, Views: 6792

• When one pH balancing system is affected then the other balancing system attempts to correct, or compensate for, the pH imbalance. - Respiratory acidosis: • Excessive CO2 is present so blood pH becomes acidic. • Compensation is increased secretion of H+ into urine and reabsorption ...

Depolarization of the SA node, Action potentials of the myocardium & ANS effects

By: HWC, Views: 6493

• A typical contractile cell in the myocardium has a resting membrane potential. • The resting membrane potential of cells in the SA node is not fixed, and is known as the pacemaker potential. • The action potential of a healthy SA nodal cell has three parts: • Pacemaker potential: ...

Bone tissue types - compact and spongy

By: HWC, Views: 6738

Bone tissue types • There are two types of bone tissue: compact and spongy. • All the bones of the skeleton have both kinds of bone tissue. • Compact (dense) bone • Arranged in osteons (Haversian systems), units of lamellae laid down in adjoining series of concentric rings. • P...