what is the primary function of white blood cells

ATI TEAS 7

Practice TEAS Science Test

1. What is the primary function of white blood cells?

A. To carry oxygen
B. To fight infection
C. To transport nutrients
D. To transport waste

Correct answer: B

Rationale: The correct answer is B: "To fight infection." White blood cells are primarily responsible for fighting infections and foreign invaders in the body, making them a critical component of the immune system. Choice A, "To carry oxygen," is incorrect as red blood cells are responsible for oxygen transport. Choice C, "To transport nutrients," is incorrect as this function is mainly attributed to blood plasma and other specialized cells. Choice D, "To transport waste," is also incorrect as waste removal is primarily handled by the kidneys and the lymphatic system, not white blood cells.

2. Which vitamin is synthesized in the skin upon exposure to sunlight?

A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin E

Correct answer: C

Rationale: Vitamin D is synthesized in the skin upon exposure to sunlight. When the skin is exposed to sunlight, a form of cholesterol in the skin is converted into vitamin D3 (cholecalciferol) through a series of chemical reactions. Vitamin D plays a crucial role in calcium absorption and bone health. Choice A, Vitamin A, is not synthesized in the skin upon exposure to sunlight; it is obtained through dietary sources. Choice B, Vitamin C, is not synthesized in the skin upon exposure to sunlight either. Vitamin C is obtained through dietary sources like fruits and vegetables. Choice D, Vitamin E, is not synthesized in the skin upon exposure to sunlight. Vitamin E is a fat-soluble vitamin that acts as an antioxidant and is obtained through dietary sources like nuts, seeds, and vegetable oils.

3. What is the primary function of the kidneys?

A. To digest food
B. To filter blood and produce urine
C. To absorb nutrients
D. To transport oxygen

Correct answer: B

Rationale: The primary function of the kidneys is to filter blood and remove waste products from the body, producing urine in the process. This function helps in maintaining the body's internal environment stable, a process known as homeostasis. Option A, 'To digest food,' is incorrect as digestion primarily occurs in the gastrointestinal system, not in the kidneys. Option C, 'To absorb nutrients,' is also incorrect because nutrient absorption mainly takes place in the intestines. Option D, 'To transport oxygen,' is incorrect as the lungs and circulatory system are responsible for oxygen transport, not the kidneys.

4. Which types of glial cells are found in the CNS?

A. Schwann cells, satellite cells
B. Astrocytes, microglia, ependymal cells, oligodendrocytes
C. Satellite cells, microglia, oligodendrocytes
D. Astrocytes, Schwann cells, satellite cells

Correct answer: B

Rationale: The correct answer is B. Glial cells in the CNS include astrocytes, microglia, ependymal cells, and oligodendrocytes. Schwann cells and satellite cells are found in the PNS. Astrocytes are the most abundant type of glial cells and are involved in nutrient support, repair, and maintenance of the extracellular environment. Microglia are the resident immune cells of the CNS, playing a role in immune defense. Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid. Oligodendrocytes are responsible for producing myelin, which insulates axons in the CNS. Understanding the specific functions of each type of glial cell is essential in grasping the complexity of the central nervous system's support and protective mechanisms.

5. Which molecules are soluble in nonpolar solvents but are hydrophobic?

A. Carbohydrates
B. Lipids
C. Proteins
D. Nucleic acids

Correct answer: B

Rationale: Lipids are hydrophobic molecules that are soluble in nonpolar solvents like oils but insoluble in water. They consist of fats, oils, waxes, and steroids and play essential roles in energy storage, insulation, and cell membrane structure. Carbohydrates, proteins, and nucleic acids are not typically soluble in nonpolar solvents and do not exhibit the same hydrophobic characteristics as lipids. Carbohydrates are usually hydrophilic and soluble in water, proteins have both hydrophilic and hydrophobic regions but are not generally soluble in nonpolar solvents, and nucleic acids are polar molecules that are not known for their solubility in nonpolar solvents.