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Hormones and the menstrual cycle Animation

By: HWC, Views: 4648

Feedback loops to the hypothalamus and pituitary gland from the ovaries during the menstrual cycle Animation for a step-by-step explanation. Production of a releasing hormone (GnRH) by the hypothalamus prods the pituitary's anterior lobe to release FSH and LH. In the ovary, FSH and LH stimula...

Male Reproductive System - Testosterone

By: HWC, Views: 8330

• Under the influence of FSH and testosterone, Sertoli cells produce androgen-binding protein (ABP) that binds to testosterone and maintains high levels of the hormone near spermatogenic cells. • Testosterone stimulates the final stages of spermatogenesis. • In addition, testosterone is...

Cardiac Cycle (Part 4 of 4)

By: Administrator, Views: 10872

Diastole and systole are two phases of the cardiac cycle. They occur as the heart beats, pumping blood through a system of blood vessels that carry blood to every part of the body. Systole occurs when the heart contracts to pump blood out, and diastole occurs when the heart relaxes after contract...

HIV replication/ Replication cycle of HIV

By: HWC, Views: 4908

Replication cycle of HIV, one of the retroviruses. The HIV virus is surrounded by a lipid envelope with embedded proteins. A coat of viral proteins surrounds two strands of RNA and the enzymes used during replication. The virus attaches to and enters the host cell. Viral reverse trans...

Carbon fixing adaptations Animation

By: HWC, Views: 1798

Different plants trap carbon by different pathways. Most C3 plants evolved in moist, temperate zones. On hot dry days they close their stomata to conserve water and oxygen accumulates. Under these circumstances, the enzyme rubisco uses oxygen in an inefficient reaction that competes with t...

Calvin cycle (The light-independent reactions )

By: HWC, Views: 7479

The light-independent reactions of photosynthesis occur in the stroma of the chloroplast. Carbon dioxide enters the leaf through tiny pores or stomata and diffuses into the chloroplast. The first stage of the Calvin cycle is the attachment of a carbon dioxide molecule to a 5-carbon ribulose bi...

Cardiac Cycle (Part 1 of 4)

By: Administrator, Views: 10752

Blood Flow through the atrium.

HIV Infection: Viral life cycle

By: HWC, Views: 7071

The series of steps that HIV follows to multiply in the body. The process begins when HIV encounters a CD4 cell. The seven steps in the HIV life cycle are: 1) binding; 2) fusion; 3) reverse transcription; 4) integration; 5) replication; 6) assembly; and 7) budding. Many viruses f...

ETC Protein Complexes & Chemiosmosis (Total ATP Production and ATP Synthase)

By: HWC, Views: 7421

You will notice that FADH2 donates two electrons further downstream than NADH. This results in only two protons being pumped across the inner membrane. The final electron acceptor for these transported electrons is oxygen. Oxygen receives these electrons, plus protons from the aqueous matrix. ...