Arterial blood gas (ABG) is a test that measures various capacities of gases to enter or exit the bloodstream, the saturation of oxygen in the blood, and materials involved in maintaining the pH level of blood. It is widely considered one of the most useful diagnostic tools for a host of circulatory conditions, and is a standard procedure for many hospital stays.

Hematocrit cannot be measured by an arterial blood gas test.

Blood is around 55% plasma, 45% erythrocytes (red blood cells), and less than 1% of leukocytes and platelets.

Pulmonary function tests or spirometric tests are tests designed to measure a host of breathing functions. Since values vary depending on body position, time of day, and other factors, most metrics have a high tolerance for variance and typically require a person to score below 80% or above 120% of their expected values before a result is considered "abnormal". These tests are most often employed diagnostically, but may also be used to check up on the progress of a treatment program.

A laryngoscope is used to view the larynx and epiglottis, but does not provide quantitative functional data.

Spirometric tests typically measure between 10-20 metrics of respiratory health, including airflow, intake/outtake, and total volume. Oxygen saturation is a measure of the blood's ability to bond oxygen to hemoglobin, and is typically measured during one or more blood tests.

The carina seems to be consistently located between the T4/T5 intervertebral disk level in most people. These vertebral levels are used as landmarks to identify the carina and, consequently, the trachea above it and the left and right primary bronchi below it.

Hormone imbalances can result in numerous diseases and disorders.

Excess adrenocorticotropic hormone can result in Cushing's disease, characterized by excess weight, fatigue, and redness and roundness in the facial features.

A deficiency in adrenocorticotropic hormone can result in Addison's disease, characterized by low blood pressure and hyperpigmentation.

Excess growth hormone can have different results, depending on the age at which the imbalance occurs. Gigantism results when there is an excess of GH during childhoos, while acromegaly results during adulthood.

Excess thyroid-stimulating hormone can result in Grave's disease, which has many symptoms similar to hyperthyroidism. Such symptoms include weight loss and hyperactivity. Grave's disease can also produce goiters.

A deficiency in thyroid-stimulating hormone can have different results, depending on the age at which the imbalance occurs. Cretinism, myxedema, and Hashimoto's disease are all caused by TSH dificiency.

An abnormal increase in the size of the thyroid gland is called a goiter. A goiter can be caused by too little secretion of thyroid hormone, or from hyperthyroidism. Depending on the stage, goiters can be undetectable to the eye, or quite obvious.

Hypothyroidism is characterized by large weight gain, slow heart rate, and slowing of movement, speech, and thoughts. Hyperthyroidism generally includes the contrasting symptoms, such as weight loss, rapid heart rate, and tremor. Addison's disease involves the hyposecretion of steroid hormones from the adrenal gland and does present with some of the same symptoms as hypothyroidism, but may include nausea, diarrhea, and craving for salty foods. The parathyroid is a major regulator of calcium and phosphate levels via parathyroid hormone. Its effects are to increase blood calcium. 

Hypocalcemia is defined as low levels of calcium in the blood. Hypercalcemia is defined as elevated levels of calcium in the blood. The body's corrective response to hypocalcemia may involve secretion of parathyroid hormone and/or activation of vitamin D.

Cushing's syndrome is an endocrine disorder characterized by the oversecretion of glucocorticoids. It is often caused by a pituitary tumor that oversecretes adrenocorticotropic hormone (ACTH) or by a cortisol-secreting tumor of the adrenal gland. Addison's disease involves the opposite cause (hyposecretion of glucocorticoids and mineralocorticoids from the adrenal gland).