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Embryonic development - Week 4

By: HWC, Views: 6852

• 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...

Embryonic development - Weeks 5 to 8

By: HWC, Views: 6766

• The second month of development is characterized by rapid development of the head and limbs as well as continued organogenesis. • During the fifth and sixth weeks growth of the brain, and therefore head, is rapid. • Hands and feets begin to form. • During week seven, even more deve...

Fetal development - Weeks 9 to 38

By: HWC, Views: 6765

Weeks 9-12 • Fetal development during the third month includes: • A large head, about 1/2 the length of the fetus. • Visible eyes and ears. • A detectable heartbeat. • Kidneys that form urine. • Gender identification. • Weak, undetectable body movements. • By the e...

Embryonic development - Week 3

By: HWC, Views: 6708

Week 3 (gastrulation) • Three primary germ layers are formed which provide cells for organ formation in the following months. • These germ cell layers are formed by a process known as gastrulation, which involves rearranging epiblast cells. • As cells from the epiblast migrate, a fain...

Osmosis - Isotonic, Hypotonic, and Hypertonic​ Solutions

By: HWC, Views: 6683

Isotonic: Equal Water moves in and out of the cell at an equal rate. The cell remains unchanged. Hypotonic: "hypo" hippo Water moves into the cell, making it swell and get fat (like a hippo). Eventually the cell can rupture and burst (aka lyse). Hypertonic: "like a raisin" Water leaves...

Bone processes - resorption and deposition, remodeling and response to stress in adult bones

By: HWC, Views: 6936

• The process of remodeling bone tissues involves bone cells resorbing or depositing minerals into bone tissue. • During resorption, bone cells break down bone tissue and release calcium and other minerals for use by other cells in the body. • Bone cells also rebuild bone tissue by depo...

Role of the respiratory system - effect of altered ventilation rates

By: HWC, Views: 7173

• The respiratory system regulates blood pH by controlling the amount of carbon dioxide removed from the blood. • Near systemic cells, carbon dioxide forms bicarbonate ions in the blood. H+ ions are also released, thereby decreasing blood pH. • At the alveolar capillaries, bicarbonate io...

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

By: HWC, Views: 7148

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...

Male Reproductive System - The gonadotropin releasing hormone

By: HWC, Views: 7380

• Hormonal mechanisms that influence male reproductive function involve endocrine tissues contained in the: • Hypothalamus of the brain. • Anterior pituitary. • Testes. • In the hypothalamus, certain neurosecretory cells secrete gonadotropin- releasing hormone (GnRH). • GnRH ...