Answer:
Villus, plural villi, in anatomy any of the small, slender, vascular projections that increase the surface area of a membrane. ... The villi of the small intestine project into the intestinal cavity, greatly increasing the surface area for food absorption and adding digestive secretions.
Answer:
A :an atom seeks to fill its outer shell of electrons
Explanation:
Reactions between atoms occur due the desire of an atom to fill their outer shell electrons.
The driving force for many interatomic bonding is the tendency to have completely filled outer energy levels like those of the noble gases.
- The various interatomic interaction which leads to chemical reaction is in a bid for the atoms to be isoelectronic in the outer energy level with the noble gases.
- This is achieved by gaining, losing or sharing of electrons.
The fluid inside of the Extracellular Matrix is Extracellular Fluid. Extracellular Fluid is also called ECF. ECF is mostly tissue fluid. It is also made up of a large amount of intravascular fluid. The remaining smaller amount of ECF is transcellular fluid.
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Answer:
Power stroke (myosin head bends) coupled with the release of ADP and phosphate
Explanation:
Muscle contraction results from myosin heads adhering to actin and attracting it inwards. It uses ATP. Myosin adhers to actin at a binding site of its globular actin protein and adheres at another binding site for ATP (hydrolyzed ATP to ADP, Pi and energy)
ATP binding prompts myosin to detach from actin, ATP is changed to ADP and inorganic phosphate, Pi by ATPase. The energy formed at this process orientates myosin head to a “cocked” direction.
The myosin head goes in the direction of the M line, holding the actin with it in the process causing the filaments to orientate nearly 10 nm in the direction of the M line--- power stroke (force is produced), the sarcomere reduces in length and the muscle contracts.
Note: The power stroke is seen when ADP and phosphate disattaches itself from the myosin head.
At the terminal point of the power stroke, the myosin head as low-energy, followed by ADP release.
The attached image shows the cross-bridge muscle contraction cycle, which is activated by Ca2+ sticking to the actin active site. And how actin moves in relation to myosin.