Search Results

Natural Selection, Species Isolation and Real World Example

By: HWC, Views: 6086

`Natural selection' is the process in which organisms with adaptive traits survive and breed in greater number than organisms without such traits. Eventually, almost all of the individuals in the population will have the same adaptive trait. This was the concept presented by Charles Darwin in ...

Male Reproductive System - Testosterone

By: HWC, Views: 7230

• 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...

B cells and antibodies

By: HWC, Views: 7473

What Are Antibodies? Antibodies, also known as immunoglobulins, are Y-shaped proteins that are produced by the immune system to help stop intruders from harming the body. When an intruder enters the body, the immune system springs into action. These invaders, which are called antigens, can be vi...

Upper Limb Arteries Animation

By: Administrator, Views: 643

Arteries A branching system of vessels that transports blood away from the heart to all body parts. All arteries have a pulse, reflecting the rhythmical beating of the heart. Arteries Certain points are commonly used to check rate, rhythm, and condition of the arterial wall. Most commonly ...

Lower Limb Arteries Animation

By: Administrator, Views: 9764

Arteries A branching system of vessels that transports blood away from the heart to all body parts. All arteries have a pulse, reflecting the rhythmical beating of the heart. Arteries Certain points are commonly used to check rate, rhythm, and condition of the arterial wall. Most commonly ...

Labor and Delivery - Placenta Cord

By: Administrator, Views: 299

Soon after a baby is conceived, a support system, comprised of the placenta and umbilical cord, begins to develop. These two structures are essential for sustaining a healthy pregnancy, explains Donald Davis, an obstetrician in Medicine Hat, Alta., and past president of the Society of Obstetricia...

Red Blood Cells - Erythropoietin (EPO)

By: HWC, Views: 6677

• The endocrine system maintains many body conditions within normal limits with feedback loops. Each endocrine feedback loop maintains homeostasis using the following components: • Stimulus - a change in a body condition. • Production cell - an endocrine cell that produces a hormone aft...

Neural regulation of mechanical digestion- CNS voluntary, ANS & ENS controlled involuntary movements

By: HWC, Views: 6581

• The gastrointestinal [GI] tract is basically a muscular tube that contains and processes food as it moves from the mouth to the anus. • Mechanical digestive functions consist of both voluntary and involuntary muscle contractions and relaxation including: • Chewing and swallowing food....

Energy sources - types

By: HWC, Views: 6890

• The amount of ATP stored in a skeletal muscle cell can only provide muscular activity for two to three seconds. • Muscle cells must be able to generate additional molecules of ATP to continue contracting. • Muscle cells can generate ATP from several processes: • Phosphogen syste...