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Semidiscontinuous DNA replication

By: HWC, Views: 7335

During DNA replication, one of the two DNA strands, the leading strand, is replicated continuously, or all at once, in the 5' to 3' direction. The other strand, called the lagging strand, is replicated discontinuously, or in pieces, in the 3' to 5' direction. This is necessary because DNA poly...

Structures that affect circulation - arterioles and vasomotor responses and venous return

By: HWC, Views: 7790

■ Small arteries and arterioles determine SVR. • Blood pressure drops significantly as blood passes through arterioles. • Decreasing arteriole radius and decreased wall elasticity are the main reasons for increased SVR. ■ Small changes in arteriole radius can cause large changes in ...

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

By: HWC, Views: 7818

• 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...

Mechanisms of capillary exchange

By: HWC, Views: 7876

■ The primary role of capillaries is to permit the exchange of nutrients and wastes between the blood and tissue cells (via interstitial fluid). ■ Oxygen and nutrients move from the blood to the cells. ■ Carbon dioxide and other wastes move from the cells to the blood. The three ba...

Factors that affect conduction rates (myelination, axon diameter & temperature)

By: HWC, Views: 7854

• Several factors determine the rate of conduction of action potentials: • Myelination • Axon diameter • Temperature • The step-by-step depolarization of an axon is called continuous conduction and occurs along unmyelinated axons. • Neurons in the PNS have many axons that ...

Darwin's Observation (Fossils, Galapagos Islands & Africa ) and Natural Selection (Adaptive Traits)

By: HWC, Views: 7612

Along Darwin's voyage, he made many observations. Each one added to his understanding of how organisms change over time. Darwin was already familiar with fossils and knew that many fossils were very different from living organisms. But, also there were some fossils that were very similar to li...

Glycolysis - and oxygen

By: HWC, Views: 7981

The first reactions involve a single 6-carbon glucose sugar undergoing phosphorylation using two ATP molecules and resulting in two 3-carbon compounds. • The rest of this pathway involves an oxidation reduction reaction, forming two reduced coenzymes, and generation of four ATP molecules. ...

TRH/TSH/Thyroid hormone

By: HWC, Views: 7249

Thyroid hormone production • A decline in metabolic rate caused by increased metabolic need or physical exertion stimulates the production of thyrotropin hormone releasing (TRH) hormone from the cells of the hypothalamus. • Thyrotropin hormone releasing hormone targets the thyrotrophic ce...

Electrical Conduction System of the Heart

By: HWC, Views: 6678

Your heart is a muscle that works continuously, much like a pump. Each beat of your heart is set in motion by an electrical signal from within your heart muscle. The electrical activity is recorded by an electrocardiogram. known as an EKG or ECG. Each beat of your heart begins with an electric...