The larynx, or voice box, contains the vocal cords, which are the source of sound production. The pharynx, or throat, has a dual role in respiration and digestion. The pharynx receives air from the nasal cavity and food and drink from the oral cavity. The trachea, or windpipe, is a rigid tube that transports air from the larynx to the bronchi. The bronchi in turn transport air into the lungs. The alveoli are thin-walled sacs where the exchange of gasses between the lungs and the blood occurs.

This is a fundamental question that checks for clear understanding of the purpose of the digestive system. The digestive system includes the mouth, esophagus, stomach, small intestine, and large intestine. The primary functions of these structures are to break down and absorb nutrients from ingested food.

The respiratory system is responsible for providing a site for gas exchange (namely the alveoli). The circulatory system delivers oxygen to tissues, while the excretory system removes nitrogenous wastes and maintains water balance via kidney function.

The larynx, or voice box, contains the vocal cords, which are the source of sound production. The pharynx, or throat, has a dual role in respiration and digestion. The pharynx receives air from the nasal cavity and food and drink from the oral cavity. The trachea, or windpipe, is a rigid tube that transports air from the larynx to the bronchi. The bronchi in turn transport air into the lungs. The alveoli are thin-walled sacs where the exchange of gasses between the lungs and the blood occurs.

Females' ovaries secrete estrogen, testosterone, and progesterone. Estrogen has many functions, including development of female secondary sex characteristics. Such charactersistics include, but are not limited to: development of breast tissue, redistribution of body fat to the hips, thighs, buttocks, and breasts, and initiation of menses. In females, testosterone functions primarily to increase sexual arousal. Progesterone, luteinizing hormone, and follicle-stimulating hormone play roles in the menstrual cycle. The corpus luteum is formed from the follicle and remains in the ovary after the egg has been released. It secretes progesterone for about two weeks, then deteriorates in the absence of a pregnancy.

This is a fundamental question that checks for clear understanding of the purpose of the digestive system. The digestive system includes the mouth, esophagus, stomach, small intestine, and large intestine. The primary functions of these structures are to break down and absorb nutrients from ingested food.

The respiratory system is responsible for providing a site for gas exchange (namely the alveoli). The circulatory system delivers oxygen to tissues, while the excretory system removes nitrogenous wastes and maintains water balance via kidney function.

The soma is the cell body of the neuron (D). The soma is the site of neuron metabolism and protein synthesis.

The dendrites of the neuron (A) receive incoming action potential signals. The axon (B) sends the action potential outward from the soma to the axon terminal (C). Vesicles of neurotransmitter are released from the axon terminal to the dendrites of other nearby neurons. Neurons can have numerous dendrites, but will only have one soma and one axon.

White matter is white due to the myelin sheath. Since the myelin sheath only covers the axon, neural tissue that is referred to as white matter is only located on a neuron's axon. Grey matter actually refers to the cell body due to its grayish appearance. Accordingly, one neuron is actually part of both the white and the gray matter in the nervous system.

The duodenum is the first section of the small intestine. It is the site of the most digestion in the small intestine (and the digestive tract in general) because pancreatic enzymes and bile are released into its lumen. These enzymes break down proteins and carbohydrates, while the bile helps to digest lipids and fats. The jejunum and ileum are primarily involved in absorbing nutrients. The cecum is part of the large intestine.

The duodenum is the first section of the small intestine. It is the site of the most digestion in the small intestine (and the digestive tract in general) because pancreatic enzymes and bile are released into its lumen. These enzymes break down proteins and carbohydrates, while the bile helps to digest lipids and fats. The jejunum and ileum are primarily involved in absorbing nutrients. The cecum is part of the large intestine.

The chemical digestion of food is facilitated by the secretion of the hormone gastrin, which stimulates the secretion of hydrochloric acid. Insulin is secreted by the pancreas in response to high levels of blood glucose. Glucagon is secreted in response to low levels of blood glucose. Aldosterone is secreted by the adrenal cortex and increases reabsorption of salt in the kidney, subsequently increasing water retention and blood volume. Thyroxine is secreted by the thyroid and increases the metabolic rate of most body cells.