Organs and Organ Systems
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Biology › Organs and Organ Systems
Which of the following hormones stimulates the secretion of hydrochloric acid by specialized stomach cell?
Gastrin
Insulin
Gylcogen
Aldosterone
Thyroxine
Explanation
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.
At what age does a female's ovary have the most eggs she will ever have in her lifetime?
At birth
In adolescence, at the start of puberty
At menopause
In the reproductive years: ages 20-30
During childhood
Explanation
The ovaries contain 1-2 million eggs at birth. This number slowly declines throughout the female's life. The quality of eggs remaining after age 35 is low, whereby years of spontaneous mutation have occurred.
Which of the following hormones stimulates the secretion of hydrochloric acid by specialized stomach cell?
Gastrin
Insulin
Gylcogen
Aldosterone
Thyroxine
Explanation
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.
The function of which respiratory system element is to produce sound?
Larynx
Pharynx
Trachea
Bronchi
Alveoli
Explanation
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.
What is the function of the digestive system?
Breakdown and absorb nutrients for use by the body
Provide a site for gas exchange
Deliver oxygen gas to the tissues of the body
Expel wastes and maintain stable internal water balance
Explanation
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.
D
A
B
C
Explanation
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.
D
A
B
C
Explanation
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.
Which section of the small intestine is responsible for the majority of chemical digestion?
Duodenum
Jejunum
Ileum
Cecum
Explanation
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.
Which of the following is the most basic functional unit found in the nervous system?
Neurons
Glial cells
Mitochondria
Action potentials
The cerebellum
Explanation
The nervous system is used to conduct electrical signals throughout the body. These signals stimulate various functions, frequently causing muscles to contract or carrying sensory signals to the brain. The brain and spinal cord are key components for organizing and interpreting these signals.
Neurons are the cells responsible for conducting electrical impulses. The impulses themselves are known as action potentials.
Glial cells provide support for the nervous system. Different types of glial cells perform different functions, such as myelination of axons, immune activity, and the production of cerebrospinal fluid. The cerebellum is a region of the brain responsible for balance and coordination. Since the cerebellum is a part of the nervous system, its structure is primarily composed of neurons. Mitochondria are organelles found in most eukaryotic cells. They generate ATP, which provides energy to the cell. Their function is not inherently linked to the nervous system.
What is the function of the digestive system?
Breakdown and absorb nutrients for use by the body
Provide a site for gas exchange
Deliver oxygen gas to the tissues of the body
Expel wastes and maintain stable internal water balance
Explanation
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.
