During which phase of the twitch contraction is there a triggering of the release of calcium ions into the sarcoplasm?
Latent period
Contraction phase
Relaxation phase
None of the above
The Correct Answer is A
A. Latent period: This is the brief delay between the stimulus and the start of contraction. During this time, the action potential travels down the T-tubules and triggers the release of Ca2+ from the sarcoplasmic reticulum.
B. Contraction phase: This is when the actual cross-bridge cycling and muscle shortening occur (after calcium has already been released).
C. Relaxation phase: This is when calcium is actively pumped back into the sarcoplasmic reticulum.
D. None of the above: Incorrect, as the latent period specifically accounts for these excitation-contraction coupling events.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
A. inspiration occurs: Inspiration happens when intrapulmonary pressure is lower than atmospheric pressure, drawing air in.
B. expiration occurs: According to Boyle's Law, air moves from areas of high pressure to low pressure. If the pressure inside the lungs is higher than the outside air, air is forced out.
C. lung tissue has collapsed: A collapsed lung (pneumothorax) occurs when the pressure in the pleural space equals atmospheric pressure, not necessarily when lung pressure is higher.
D. the bronchioles are obstructed: Obstruction changes resistance to airflow, but the pressure gradient itself is what defines the phase of breathing.
Correct Answer is B
Explanation
A. a membrane that lines body cavities: While membranes are made of tissues, this describes a specific structure (like a serous membrane), not the definition of tissue itself.
B. a group of similar cells that perform a common function: This is the standard biological definition of a tissue, which sits between the cellular and organ levels of organization.
C. a thin sheet of cells embedded in a matrix: This describes specific types of connective or epithelial tissues, but is too narrow to define all tissues.
D. the most complex organizational unit of the body: This is incorrect; the "organism" is the most complex unit, followed by organ systems and then organs.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.