Which of the following hormones regulates blood calcium levels?

Cardiac muscles have intercalated discs that enable them to contract in a coordinated manner. Skeletal muscles do not have intercalated discs, as their contraction is under voluntary control and does not require the same level of synchronization seen in the involuntary contraction of cardiac muscle.

A chlorine molecule contains the fewest covalent bonds among the options provided. It consists of two chlorine atoms bonded together by a single covalent bond. Compared with the other options, ammonia has three covalent bonds, methane has 4 while water has 2.

The gray matter of the brain primarily consists of neuron cell bodies, along with dendrites, glial cells, and unmyelinated axons. It appears gray because it lacks the white fatty myelin sheath that covers many nerve fibers.

The kidneys are the primary organs involved in the excretion of nitrogenous wastes. Nitrogenous wastes are mostly products of protein metabolism in the liver. One of the common nitrogenous waste products is urea, which is excreted through the kidneys.

Most of the carbon dioxide from the blood moves into the alveoli through the process of diffusion down a concentration gradient. In the lungs, there is a higher concentration of carbon dioxide in the blood compared to the alveoli. Its molecules, therefore, move from an area of higher concentration (blood) to an area of lower concentration (alveoli) until equilibrium is reached. This is a passive process and does not require energy or carrier proteins.

From the heart, blood flows through major arteries, which then branch to give rise to arterioles, which then divide into capillaries that deliver blood to the target organ.

The inner lining of the uterus is the source of blood and mucosal tissue that is shed during menstruation.

The parathyroid hormone (PTH) from the parathyroid glands is important in serum calcium regulation. It increases blood calcium levels by stimulating osteoclasts to break down bone and release calcium into the bloodstream. PTH also enhances the absorption of calcium from the intestines and the kidneys.

Rationale

Chromatin refers to a complex of DNA and proteins in human cells. This material is packaged by histones to make up the chromosomes. The chromosomes then contain genetic information that is heritable.

The pituitary gland produces prolactin, which regulates milk production