Question

1. identify the four components of a negative - feedback loop and explain what would happen if secretion of a body chemical controlled by a negative - feedback system became too great.
2. what regulatory processes would your body use if you were trapped by a blizzard in an unheated, uninsulated cabin in the woods?
3. in which direction would an mri scanner move to produce sequential images of the body in the frontal plane, and in which direction would an mri scanner move to produce sequential images of the body in the sagittal plane?
4. if a bullet were to penetrate a lung, a major thoracic body cavity, which layer of the serous membrane would it encounter first?
5. which medical imaging technique is most dangerous to use repeatedly, and why?
6. explain why ultrasound imaging is the method of choice for studying fetal growth and development.

Explanation:

1. The four components of a negative - feedback loop are the stimulus, sensor, control center, and effector. If the negative - feedback system controlling a body chemical became too great, the level of the chemical would drop too low as the system over - corrects.
2. If trapped by a blizzard in an unheated, uninsulated cabin in the woods, the body would use shivering (a form of thermogenesis) and vasoconstriction (to reduce heat loss from the skin) as regulatory processes.
3. To produce sequential images of the body in the frontal plane, an MRI scanner would move from anterior to posterior or vice - versa. To produce sequential images in the sagittal plane, it would move from left to right or right to left.
4. If a bullet penetrates a lung, it would encounter the visceral pleura first as it is the layer of the serous membrane that directly covers the lung.
5. X - ray imaging is dangerous to use repeatedly because it uses ionizing radiation which can damage cells and increase the risk of cancer.
6. Ultrasound imaging is the method of choice for studying fetal growth and development because it uses high - frequency sound waves which are non - ionizing and do not pose a risk to the developing fetus.

Answer:

1. Components: stimulus, sensor, control center, effector. Outcome of over - correction: chemical level drops too low.
2. Regulatory processes: shivering, vasoconstriction.
3. Frontal plane: anterior - posterior or vice - versa. Sagittal plane: left - right or right - left.
4. Visceral pleura.
5. X - ray imaging; due to ionizing radiation and cancer risk.
6. Ultrasound imaging; because of non - ionizing sound waves and safety for fetus.