The structure that functions as a diaphragm to control pupil size is the
A. anterior chamber.
B. suspensory ligament.
C. cornea.
D. iris.
E. ora serrata.
Answer: D
You might also like to view...
The flow rate of blood through an organ is in part determined by the relative dilation or constriction of arterioles in that organ
Indicate whether the statement is true or false.
Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. How do you suppose these drugs work?
A. They prevent calcium from entering cardiac muscle, thus slowing down the heart rate. B. They prevent calcium from entering smooth muscle, thus allowing the muscle to relax. C. They prevent calcium from entering the sarcoplasmic reticulum of smooth muscle. D. They prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle. E. They stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin.
Fred was admitted to the cardiac unit with chest pains. No arrhythmias and no large changes in the heart rate were observable
Blood samples taken over the next few days showed no increase in enzymes such as creatine phosphokinase. A possible treatment of the condition is A. beta adrenergic blocking agents. B. nitroglycerin. C. calcium channel blocking agents. D. aspirin. E. exercise.
Identify the structures that contribute to the slow onset of contraction and prolonged contraction phase in cardiac muscle tissue
A. Desmosomes B. Gap junctions C. Intercalated discs D. T-tubules E. Terminal cisternae