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

By: HWC, Views: 7002

• 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...

Mechanisms of capillary exchange

By: HWC, Views: 6774

■ The primary role of capillaries is to permit the exchange of nutrients and wastes between the blood and tissue cells (via interstitial fluid). ■ Oxygen and nutrients move from the blood to the cells. ■ Carbon dioxide and other wastes move from the cells to the blood. The three ba...

Darwin's Observation (Fossils, Galapagos Islands & Africa ) and Natural Selection (Adaptive Traits)

By: HWC, Views: 6562

Along Darwin's voyage, he made many observations. Each one added to his understanding of how organisms change over time. Darwin was already familiar with fossils and knew that many fossils were very different from living organisms. But, also there were some fossils that were very similar to li...

Introduction to C-Section

By: Administrator, Views: 273

Caesarean section, also known as C-section, or caesarean delivery, is the use of surgery to deliver babies. A caesarean section is often necessary when a vaginal delivery would put the baby or mother at risk. This may include obstructed labor, twin pregnancy, high blood pressure in the mother, br...

Labor and Delivery - Placenta Cord

By: Administrator, Views: 299

Soon after a baby is conceived, a support system, comprised of the placenta and umbilical cord, begins to develop. These two structures are essential for sustaining a healthy pregnancy, explains Donald Davis, an obstetrician in Medicine Hat, Alta., and past president of the Society of Obstetricia...

Labor and Childbirth - The Three Stages of Labor: Dilation, Expulsion & Placental مراحل الولادة

By: HWC, Views: 7146

Regulation of labor and birth - effects of estrogen and oxytocin on onset of labor • Just prior to birth, high placental corticotropin-releasing hormone levels stimulate the production of more estrogen. • High estrogen levels overcome the inhibitory effects of progesterone on uterine sm...

Second Stage of Labor and Delivery

By: Administrator, Views: 515

During labor forceful contractions move the fetus down the birth canal and expel it from the uterus. Signs and symptoms that labor is about to start can occur from hours to weeks before the actual onset of labor. Braxton Hicks contractions Irregular contractions that begin in the second trim...

First Stage of Labor and Delivery Video

By: Administrator, Views: 9812

During labor forceful contractions move the fetus down the birth canal and expel it from the uterus. Signs and symptoms that labor is about to start can occur from hours to weeks before the actual onset of labor. Braxton Hicks contractions Irregular contractions that begin in the second trim...

Brain Lobes Animation

By: Administrator, Views: 10781

The brain’s cerebral cortex is the outermost layer that gives the brain its characteristic wrinkly appearance. The cerebral cortex is divided lengthways into two cerebral hemispheres connected by the corpus callosum. Traditionally, each of the hemispheres has been divided into four lobes: front...