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Atrophy

By: Administrator, Views: 9468

Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, excessive amount of apoptosis of c...

Apicomplexan life cycle Animation

By: HWC, Views: 1002

Malaria is caused by the sporozoan, Plasmodium. It is transferred to humans by mosquitoes. When an infected mosquito feeds, infective sporozoites move from her salivary glands into the human body. The bloodstream carries the sporozoites to the liver. Here, they reproduce asexually and...

Labor and Childbirth - The Three Stages of Labor: Dilation, Expulsion & Placental مراحل الولادة

By: HWC, Views: 7146

Regulation of labor and birth - effects of estrogen and oxytocin on onset of labor • Just prior to birth, high placental corticotropin-releasing hormone levels stimulate the production of more estrogen. • High estrogen levels overcome the inhibitory effects of progesterone on uterine sm...

Embryonic development - week 1 and 2

By: HWC, Views: 6686

The first through eighth weeks after fertilization are called the embryonic. Week 1 • Within a day, the zygote begins mitotic cell division (cleavage) forming blastomeres. By the 4th day, the blastomeres have formed a solid ball called a morula. • The morula enters uterine cavity ar...

Embryonic development - Week 4

By: HWC, Views: 6848

• The flat trilaminar embryonic disc undergoes embryonic folding to form a three-dimensional cylinder shaped embryo. • Most organ systems continue, or start, to develop (organogenesis): • The nervous system and chorion continue to develop. • The heart and the rest of the cardiovas...

Proteins Defined, Hierarchy & Composition of Cells

By: HWC, Views: 6157

Proteins are long chains of amino acids linked together by peptide bonds. Together with the other three biological macromolecules—carbohydrates, lipids, and nucleic acids—proteins are the building blocks of cells. Proteins are the most complex and abundant biological macromolecules in cel...

Head and Neck Movement Animation

By: Administrator, Views: 297

Interestingly, head and neck muscles are the first ones that the baby can control. A baby can hold his head up before he can sit erect. The muscles of the head and neck perform many important tasks, including movement of the head and neck, chewing and swallowing, speech, facial expressions, an...

Simple Diffusion - gases and nonpolar compounds transport

By: HWC, Views: 6999

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 ...

Blood Flow through the Human Heart

By: HWC, Views: 6430

The heart is the pump of the human circulatory system. The left side of the heart has two connected chambers, the left atrium and the left ventricle. The right side of the heart also has two connected chambers, the right atrium and the right ventricle. These two sides, or pumps, of the heart are ...