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X chromosome inactivation in calico cats

By: HWC, Views: 4692

X chromosome inactivation causes a mosaic tissue effect in calico cats. what makes this female calico cat "calico." Like all mammals, this cat began her life as a single cell. That cell had two X chromosomes, one from each parent. One of the chromosomes carried a dominant allele for the ...

B cells and antibodies

By: HWC, Views: 8528

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...

Normal and abnormal blood pH

By: HWC, Views: 7797

• Dissociation of the chemical substances in the body fluids can result in the production of free hydrogen ions. • The pH scale is used to measure the concentration of hydrogen ions in solution. • Normal blood pH values vary around 7.4. • When hydrogen ion concentration increases, t...

Role of complement proteins

By: HWC, Views: 7497

• Non-specific and specific defense mechanisms work through the functions of complement proteins. • As soon as pathogens penetrate the physical barrier of the skin, other resistance mechanisms begin. • Cells, such as macrophages, phagocytize pathogens. • These cells increase exposu...

Green alga life cycle Animation

By: HWC, Views: 2368

Chlamydomonas zoospores are haploid flagellated cells. As long as conditions are favorable, these cells reproduce asexually. As many as sixteen cells may form by mitosis within a parent cell. Daughter cells escape when the cell wall ruptures. When conditions become less favorable, the...

Types of synapses - electrical & chemical

By: HWC, Views: 7852

• Neurons communicate with one another or effector cells via synapses that allow information to be filtered and integrated. • The two types of synapses are: • electrical • chemical. • Electrical synapses, also known as gap junctions, contain many ion channels (connexons) conne...

Carbohydrate Metabolism: Introduction to renal processes and filtrate formation and composition

By: HWC, Views: 7929

• At the nephron, the three process responsible for the formation of urine include: • Glomerular filtration. • Tubular reabsorption. • Tubular secretion. • During filtration, a filtrate is formed within the renal tubule. • Reabsorption is the conserving of water and many s...

Gastrin (gastric emptying) & Secretin (buffering gastric acid)

By: HWC, Views: 7262

• Gastrin also binds to the smooth muscle cells in the stomach causing: • Increased gastric motility. • Opening of pyloric sphincter. • Increased gastric emptying. • The intestinal phase of digestion begins as chyme enters the duodenum. • The chyme's acidity can damage int...

Neural regulation of blood pressure - baroreceptor and chemoreceptor reflexes

By: HWC, Views: 8008

• The nervous system regulates blood pressure with two reflex arcs: baroreceptor and chemoreceptor. ■ Baroreceptors (pressure) and chemoreceptors (chemical) are located in the carotid sinus and aortic arch. • Carotid sinus reflex helps maintain normal blood pressure in brain. • Ba...