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Types of antimicrobial substances (interferons & complement protein)

By: HWC, Views: 7752

• Found in blood and interstitial fluids. • Discourage microbial growth. • Include interferon and complement proteins. • Produced and released by virus-infected lymphocytes. • Enter new cells and inhibit viral replication. • Act against a large variety of viruses (non-speci...

Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 7950

• Tubular cells of the proximal convoluted tubule and collecting tubules can alter filtrate pH and therefore blood pH. • These cells can affect blood pH with two coupled mechanisms: • Reabsorption of bicarbonate ions. • Secretion of hydrogen ions. • The reabsorption of bicarbonate...

Stomach peristalsis - Movement of Food Through the Small Intestine

By: HWC, Views: 7746

Peristalsis is a series of wave-like muscle contractions that moves food to different processing stations in the digestive tract. The process of peristalsis begins in the esophagus when a bolus of food is swallowed. The strong wave-like motions of the smooth muscle in the esophagus carry the food...

Factors that influence muscle tension - Sarcomere length and force, understretched and overstretched

By: HWC, Views: 7752

• Muscle tension generated through the contraction of muscle cells provides the force necessary for the muscular system to function. • The amount of tension produced depends on several factors: • Sarcomere length Frequency of stimulation • Motor unit size • Recruitment of moto...

Heart sounds

By: HWC, Views: 7607

During a normal, healthy heartbeat, or what we call a cardiac cycle, the top two chambers of the heart, called the atria, contract simultaneously. Then, as they relax, the bottom two chambers, called the ventricles, contract. This explains what happens during a cardiac cycle, but what it doesn't ...

Types of disease resistance: innate defenses & immunity

By: HWC, Views: 7963

Our immune system protects us and helps fight off disease. Microorganisms, small microscopic organisms, and viruses are everywhere. Ever thought about how many are on that door you just opened? Many microbes and viruses can cause disease and are termed pathogens. Plants and animals have what i...

Cerebral Cortex Animation

By: Administrator, Views: 11056

The cerebral cortex (plural cortices), also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain, in humans and other mammals. It is separated into two cortices, by the longitudinal fissure that divides the cerebrum into the left and right cerebral hemisp...

Basic rhythm - control centers in medulla oblongata, spirograph and normal tidal cycle

By: HWC, Views: 7578

• Normal ventilation is rhythmic and involves continuous cycles of inspiration and expiration. • Various regions of the brain closely regulate this rhythmic pattern of ventilation. • The rhythmicity area in the medulla regulates the basic rhythm of ventilation. • The medullary rhy...

Angiotensin II - kidneys, adrenal glands and dehydration

By: HWC, Views: 7846

• Angiontensin II targets cells in the proximal convoluted tubule of the nephron. ■ The reabsorption of Na+ and Cl- ions sets up an osmotic gradient favoring the retention of water. • Decreases urine production and increases blood volume and pressure. • Angiontensin II targets zon...