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Simple Diffusion - Ion transport

By: HWC, Views: 6732

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...

ADH and the arterioles, kidneys, sweat glands and the Atrial natriuretic peptide (ANP)

By: HWC, Views: 6792

• ADH is also known as vasopressin. • Produced by hypothalmus and secreted by neurosecretory cells in posterior pituitary gland. • Responds to high blood osmotic pressure representing low amounts of water in the blood. • Binds to smooth muscle cells in walls of arterioles, stimulate...

Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 6789

Once the muscle cell has been excited it will contract. • A muscle action potential will trigger the release Of Ca2+ ions into the sarcoplasm. • The Ca2+ ions bind to the regulatory proteins and trigger contraction. • Within skeletal muscle cells are structures that provide the ability...

Acid-base imbalances - compensation of metabolic acidosis and alkalosis

By: HWC, Views: 6944

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...

Neurotransmission at chemical synapses & Excitory and inhibitory potentials

By: HWC, Views: 6580

• A series of events occur at chemical synapses in order to communicate with the adjacent cell. • The action potential arrives at the presynaptic membrane. • The depolarization phase of the action potential opens voltage gated Ca+ channels. • increased inflow of Ca+' into the cyto...

Renin/Angiotensin (water gain from urine & Na ion and water reabsorption)

By: HWC, Views: 6568

• Sensing declining blood pressure or blood volume, juxtaglomerular cells of the nephron release renin, an enzyme that promotes the formation of angiotensin II. • Angiotensin II targets smooth muscle cells in blood vessels that provide blood to the nephron. • Angiotensin II causes thes...

Acid-base imbalances - compensation of respiratory acidosis and alkalosis

By: HWC, Views: 6820

• 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 ...

Primary Active Transport - electrochemical gradient and ion transport / water movement

By: HWC, Views: 6778

Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consis...

Graded potentials - electrical characteristics and types

By: HWC, Views: 6943

• A graded potential occurs when a gated channel is opened or closed, altering ion flow through the membrane. • Changes in ion and charge distributions cause voltage changes to the resting membrane potential. • The strength of the stimulus determines the number of gated channels affect...