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

By: HWC, Views: 7629

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...

Steps of glucose catabolism

By: HWC, Views: 7924

• During digestion, complex carbohydrates are hydrolyzed into monosaccharides, primarily glucose. • The catabolism of glucose is the primary source of energy for cellular production of ATP. • The anabolism of glucose is important in regulating blood glucose levels. • Glucose cat...

Metabolic Rate, Heat and Thermoregulation - response to heat and cold stresses

By: HWC, Views: 7959

• A neuron group in the anterior portion of the hypothalamus controls heat balance. • Neurons in the preoptic region of the hypothalamus integrate signals that come from thermoreceptors. • The temperature control center in the preoptic region propagates control signals to two other part...

A Human Karyotype Preparation Animation

By: HWC, Views: 4893

Blood is collected from the person being analyzed. The blood is added to a growth medium that also contains a chemical that stimulates mitosis. The cells are allowed to grow in this medium for two or three days at body temperature. Colchicine is added to arrest cell division at metaphase. T...

HIV Infection: Viral life cycle

By: HWC, Views: 7090

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...

Coaductile pathway, Timing of contraction signal & Conduction system and ECG

By: HWC, Views: 7938

• When the system is healthy, the signal to contract the entire conduction system originates in the SA node - known as the heart's pacemaker. • The SA node triggers contraction because it depolarizes at a faster rate than other parts of the conduction system. • The wave of excitation fr...

Hyperglycemia Animation

By: Administrator, Views: 12300

Hyperglycemia means high (hyper) glucose (gly) in the blood (emia). Your body needs glucose to properly function. Your cells rely on glucose for energy. Hyperglycemia is a defining characteristic of diabetes—when the blood glucose level is too high because the body isn't properly using or doesn...

Hormonal regulation of pregnancy - weeks 17 through 38

By: HWC, Views: 7995

• Estrogens increase uterine blood flow, maintaining the endometrium during pregnancy. • High levels of estrogen and progesterone inhibit the synthesis of milk. Progesterone inhibits myometrial contractions of the uterus to prevent premature birth. • Relaxin inhibits myometrial contract...

Lipid absorption - end products & transport mechanism

By: HWC, Views: 7270

• The end products, fatty acids and monoglycerides, depend on bile salts for absorption. • Bile salts form micelles (tiny spheres), which ferry fatty acids and monoglycerides to epithelial cells. • Free fatty acids, monoglycerides, and some phospholipids and cholesterol molecules, dif...