Answer:A. The release of calcium ions causes myosin and actin to attach to each other.
The contraction of skeletal muscles takes place by induction of a nerve impulse, which produces a movement and the interaction of the filaments containing proteins named as actin and myosin. This interaction of filaments is regulated by proteins called tropomyosin and troponin present on the actin filaments. The motor nerve causes the depolarization of the muscle membrane sarcolemma. This triggers the sarcoplasmic reticulum to release calcium ions. This calcium binds to troponin and thus allows the tropomyosine strand on the actin filament to displace so that the part of the actin where myosine head needs to be attached remain uncovered. Binding of the actin myosine filament results in contraction.
Hence, the release of calcium ions causes myosin and actin to attach to each other causes muscle contraction.
Answer:
C
Explanation:
Meiosis is the creation of sex cells so it isn't A or B. Meiosis makes two different gametes that are not identical so it has to be C
<span>The answer to this question would be: tissues; decrease
Oxygen is delivered to the tissue by the heart. It will be unloaded in the tissue, causing the oxygen level in the blood to be decreased. After that, the blood also picks up the carbon dioxide so its level will be increased.
In lungs, the carbon dioxide will be unloaded and oxygen will be loaded back into the blood.</span>
Answer:
The urinary system removes excess substances and waste products from the metabolism from the body through the urine, contributing to the maintenance of homeostasis, the chemical composition of the internal environment. Urine is produced in the kidneys, passes through the ureters to the bladder, where it is stored and is released into the exterior through the urethra.
The kidneys perform the main work of the urinary system comparing with the other parts of the system, acting primarily as passageways and storage areas. With the filtration of blood and the formation of urine, the kidneys contribute to homeostasis of body fluids in a number of ways, such as: Regulation of the ionic composition of blood; Maintenance of blood osmolarity; Regulation of blood volume; Blood pressure regulation; PH regulation of blood; Hormone release; Regulation of blood glucose level; Waste excretion and toxic substances.
Ureters - They are two tubes that carry urine from the kidneys to the bladder. The ureters are capable of performing rhythmic contractions called peristalsis. Urine moves along the ureters in response to gravity and peristalsis.
Bladder - The urinary bladder acts as a temporary reservoir for urine storage. It is a hollow, elastic muscular organ that in men is directly anterior to the rectum and in women, is located in front of the vagina and below the uterus.
Urethra - is a tube that conducts urine from the bladder to the outside, being lined with mucosa that contains a large amount of mucus-secreting glands. The urethra opens outwards through the outer ostium of the urethra.
