Question

Thermoreceptors detect body temperature and send impulses to the brain for analysis. If body temperature is low, the brain will signal skeletal muscles to perform brief, repeated contractions to help generate heat. In this example, what is the effector?
A. Skeletal muscles
B. Body temperature
C. Brain
D. Thermoreceptors

Answer 1

Answer:

A. Skeletal muscles

Explanation:

An effector is a group of cells, an organ, gland or any part of the body that acts to bring about a change in response to a nerve impulse from the CNS.  

In the case of thermogenesis as stated in the question above, where a drop in temperature is detected by thermoreceptors in the CNS, the part of the body that responds in returning the body temperature back to its baseline are the skeletal muscles. The skeletal muscles are the effectors that responded in repeated contracions to generate heat.

Answer 2

Answer:

A

Explanation:

In order to maintain homeostatic balance in human, negative feedback loop and sometimes positive feedback loop are usually employed. The control mechanism consists of receptors and effectors (muscles and glands). The Receptors are sensory cells that acts like sensors to detect changes stimuli from the internal and external environments and relay these as input to the control center the brain. The brain processes the input and  send the information as output to the effectors to bring about a corrective effects.

The control by  the  negative and positive loop  are usually within the set-points so that the homeostatic balance of the body is maintained.  

In this present scenario, the imbalance in body temperature (drop )is detected by the receptors in  the skin (thermoreceptos, so named because they are sensitive to heat). They sent input as temperature fluctuations to the brain the control center.Analysis by the brain is relayed as output to the effectors (skeletal muscles) to contract, repeatedly. This is shivering. It is a thermogenic mechanism of increasing body temperature when it drops.

Therefore the skeletal muscles is the effector  because , it causes a  biological change(shivering) in the body reverse  the  rise in body temperature, and  returns  it to normal level.

The entire process is called thermogenesis. Once the temperature reached the set-point the thermoreceptors, sense this and send  corrective input for the brain to stop the stimulation of the temperature control center : hypothalamus  to reduce the output to the effectors Therefore, he skeletal muscles relaxed.  and shivering is stopped

Although this is a corrective measure,  it has disadvantage of withdrawing  heat energy from the body core temperature via  vasodilitation and loss to  the surrounding environment via convention.