Compare and contrast the roles of cytotoxic T cells and NK cells.
What will be an ideal response?
Cytotoxic T cells bind to and destroy specific virus-infected self cells and sometimes cancer cells, as part of the
immune system. NK cells are part of the innate defenses, secreting antiviral cytokines and attacking host cells that
lack MHC-I complexes as a result of a viral infection or cancer.
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Joints can be classified structurally as
A) bony. B) fibrous. C) cartilaginous. D) synovial. E) All of the answers are correct.
Lipophilic hormones
A) bind to receptors inside the cytoplasm or nucleus. B) bind to receptors on the surface of the cell. C) function by activating cAMP. D) function by way of a second messenger system. E) cannot diffuse through the cell membrane.
Seawater has an osmolarity of around 1000 mOsm, mostly from dissolved sodium. Given what you know about the osmolarity in most of the cells in the body, why is it dangerous to drink seawater?
A) In the cardiovascular system, the higher sodium levels would decrease the pressure in the arteries making it more difficult to get blood to the systemic capillaries. B) In the digestive system, the seawater would draw more water out of the bloodstream than would be absorbed, leading to severe dehydration. C) In membrane transport, the increased sodium concentration would slow down secondary active transport of glucose into cells. D) In the nervous system, the additional extracellular sodium concentration would slow down the normal flow of sodium ions used to generate action potentials. E) In the renal system, the osmolarity of the medulla of the kidney would become even more concentrated.
Which of the following systems functions as a means to rid the body of carbon dioxide?
a. Lymphatic system. b. Urinary system. c. Respiratory system. d. Digestive system.