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Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 7948

• 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...

Phases of the Female Reproductive Cycle - Hormonal regulation

By: HWC, Views: 8170

FSH, LH and estrogen • FSH travels through the bloodstream from the anterior pituitary to the ovaries. • FSH promotes follicular growth. Increased follicular growth promotes estrogen production. • Small increases in blood estrogen levels inhibit the release of FSH and LH into the bl...

Uterine (menstrual) cycle - phases

By: HWC, Views: 7708

• The uterus goes through a cyclical developmental pattern to be ready for implantation and support of an embryo. • The uterine, or menstrual, cycle is under the control of ovarian horrnones. • The uterine cycle also has three phases: • Menstrual phase • Proliferative phase â€...

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

By: HWC, Views: 7750

• 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: 7605

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 ...

Fertilization Animation

By: Administrator, Views: 429

At conception, the gender and other biologic traits of the new individual are determined. The zygote is genetically complete and immediately begins to divide, forming a solid mass of cells called a morula. When the developing embryo (stage of development between weeks 2 and 8) reaches the ute...

Types of disease resistance: innate defenses & immunity

By: HWC, Views: 7961

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...

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

By: HWC, Views: 7575

• 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: 7843

• 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...