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Haustral churning, Gastrocolic reflex and mass peristalsis & Defecation

By: HWC, Views: 6785

• As the cecum becomes filled and distends, a local reflex causes: • Closure of the ileocecal valve. • Activation of haustral churning. • Haustral churning mixes the chyme, which helps absorption of water, salts, and vitamins. • Haustral churning propels the contents of the colo...

Stomach peristalsis - Movement of Food Through the Small Intestine

By: HWC, Views: 6673

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...

Origin of organelles Animation

By: HWC, Views: 289

Possible origins of the nucleus and other organelles. Some prokaryotic cells have infoldings of their plasma membrane. These infoldings may have served as channels from the cytoplasm to the cell surface. These membranous folds may have evolved into the endoplasmic reticulum and the nuclear e...

Digestive chemicals - water, gastric acid, bile & bicarbonate

By: HWC, Views: 6360

• 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 ...

Action potentials - electrical characteristics and generation

By: HWC, Views: 6576

• An action potential is the nervous impulse or signal for long distance communication. Each action potential is generated at the cell's trigger zone. • Action potentials are considered an all-or-nothing phenomena because they are either generated or not. • The generation of an action...

Frequency of stimulation and force (Recruitment of motor units and force)

By: HWC, Views: 6993

• Muscle tension depends on the frequency of stimulation. • Muscle twitch: First stimulus. • Wave summation: When a second stimulus excites a partially relaxed muscle, producing a stronger contraction. • Unfused tetanus: Successive stimulations at the same frequency, producing a se...

Magnetic resonance imaging (MRI)

By: Administrator, Views: 9764

Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body in both health and disease. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the or...

Parkinson's Disease

By: Administrator, Views: 10223

Parkinson's disease (PD) is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. As the disease worsens, non-motor symptoms become increasingly common. The symptoms generally come on slowly over time. Early in the disease, the most obvious are shak...

How does asthma work?And How do you treat asthma?

By: HWC, Views: 5598

These are the parts of the respiratory system. Sinuses and Nasal Passages Mouth Windpipe (Trachea) Lungs Airways (Bronchial Tubes) Airsacs (Alveoli) When we breathe, air moves easily in and out of the lungs. The small airways are also called bronchial tubes. The side of the tube is...