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The Hypothalamus: The Body's Thermostat (Human Thermostat)

By: HWC, Views: 6975

Normal body function requires a relatively constant body temperature, which is regulated by the body's thermostat, a region of the brain called the hypothalamus. The hypothalamus generates a temperature set point for the body and appears to be the major site for the integration of temperature inf...

Muscle Twitch and Muscle Tension - Motor unit size and force

By: HWC, Views: 7982

• A motor unit is a group of muscle cells controlled by a single neuron. • A stimulus of sufficient intensity will cause all the cells in the motor unit to contract. • A single contraction, caused by a single action potential, is called a muscle twitch. • Latent period: A brief per...

ribosome

By: HWC, Views: 7483

The trp operon in E. coli contains five structural genes corresponding to enzymes that convert chorismate into tryptophan. The trpE gene contains a 5' untranslated region that plays an important role in the regulatory mechanism called attenuation. The 5' UTR contains four regions. Region 1 en...

Muscle Fatigue and Recovery

By: HWC, Views: 7520

• After prolonged activity, muscle contraction weakens, and the muscle enters a state of fatigue. • Fatigue results from in muscle cells, such as: • Inadequate release of calcium ions • Depletion of energy sources • Lack of oxygen • Build up of lactic acid other metabolic w...

Cerebral Cortex Animation

By: Administrator, Views: 11082

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...

Digestive chemicals - water, gastric acid, bile & bicarbonate

By: HWC, Views: 7449

• Water is the most abundant molecule in ingested fluids. • Water plays a primary role in hydrolytic digestive reactions. • Helps liquefy and transport digestive foodstuffs down the tract. • Transports secretions from accessory digestive organs to gastrointestinal tract. • Aids ...

Factors that increase metabolic rate and heat production

By: HWC, Views: 7786

• All vital biochemical reactions are temperature dependent. • The overall rate at which metabolic reactions use energy is known as the metabolic rate. • Metabolic rate greatly determines body temperatures. • Temperature is maintained by balancing the loss of heat to the environment...

Requirements for nervous signals

By: HWC, Views: 7696

• The function of neurons is to allow communication between cells, thereby maintaining homeostasis. • Electrical signals, called membrane potentials, travel along the membranes of the neurons. • Voltage variability and distance traveled determine the type of nervous signal. 1. Graded...

Morphology of a tomato plant

By: HWC, Views: 2260

The bulk of the plant body is comprised of ground tissue. Vascular tissue threads through the ground tissue. It distributes water, solutes, and organic substances through the plant body. Dermal tissue covers and protects the surfaces of the root and shoot systems.