I think the answer is letter A. I hope this helps and i would have someone check this to make sure it's the correct answer for sure.
Answer:
by the sarcoplasmic reticulum's calcium ion pumps
Explanation:
Rigor mortis or postmortem rigidity, is a state caused by chemical changes in the muscles that occur post mortem and cause the limbs of the corpse to stiffen.
This occurs because after death, there is no cellular respiration and consequently, no oxygen nor ATP (ATP is required for the muscle relaxation).
Calcium enters the cytosol after death because it is released due to the deterioration of the sarcoplasmic reticulum and due to the breakdown of the sarcolemma. Ca2+ ions activate the formation of actin-myosin cross-bridging necessary for the contraction. Muscles are unable to relax, because myosin heads continue to bind with the active sites of actin and there is no ATP to destabilize the myosin-actin bond.
Please provide either a screenshot or a text format of the options
Answer:
1. Ends of the respiratory branches are called alveoli.
2. C. To control blood flow to different areas of the body depending on activities
Explanation:
1. The trachea divides into left and right primary bronchi which in turn divide multiple times upon entering the lungs and make the bronchial tree.
The final branches of the bronchial tree are the terminal bronchioles that lead to alveoli. The alveoli are the balloon-shaped structures and serve as the site of gas exchange between the blood and inhaled air.
2. The opening and closing of sphincters of capillary beds regulate the direction of blood flow. The opening of sphincters allows the blood to flow into associated branches of capillary beds while closed sphincters direct the blood from arterioles to venules via thoroughfare channel.
This local change in blood flow is responsible for the autoregulation of blood flow to different tissues to match their respective metabolic demands. For example, during physical activity, more blood is directed to skeletal and cardiac muscles.
