When you get cold you may shiver. The shivering response is...

When you get cold you may shiver. The shivering response is a reflex in which the hypothalamus in the brain integrates sensory input, comparing input against a temperature set point. When a threshold signal is detected, nerves of the somatic nervous system that innervate skeletal muscle are stimulated. The extension and contraction of muscle cells releases heat energy that elevates the body temperature. A. Construct a representation of the information flow for the shivering response. Annotate your representation to include $\bullet$ the sensory input $\bullet$signal transmission to the hypothalamus $\bullet$signal transmission from the hypothalamus to the somatic nervous system $\bullet$transmission to muscle tissue $\bullet$and output response. Include in your annotation the negative feedback loop that is established. B. Shivering occurs when you have a fever even though your body temperature has not fallen. Identify the component of the information flow represented above that can cause this effect and describe how the brain has integrated the immune system and nervous system to maintain homeostasis. Thermogenesis from accelerated metabolism in adipose (fat) tissue is a non-shivering response to a cold stimulus. Using a neurotropic virus, investigators are able to trace the paths of nerves in animals. Neurons infected by virus can then be visualized by exposing the tissue to antibodies that can be stained or using dyes that fluoresce. Ryu and co-workers (Journal of Neuroscience, 35, 2015) used this technique to demonstrate communication between nerves of the sympathetic nervous system and nerves of the sensory nervous system innervating thermoreceptors that are sensitive to hot and cold. C. Construct a representation of information flow and annotate the representation with labels for $\bullet$signal input caused by low temperature $\bullet$signal transmission through nerves of the sensory system $\bullet$transmission of signal from the sensory system to the sympathetic system $\bullet$transmission to adipose cells $\bullet$output response of cells. Include in your annotation the negative feedback loop that is established.

When you get cold you may shiver. The shivering response is a reflex in which the hypothalamus in the brain integrates sensory input, comparing input against a temperature set point. When a threshold signal is detected, nerves of the somatic nervous system that innervate skeletal muscle are stimulated. The extension and contraction of muscle cells releases heat energy that elevates the body temperature.
A. Construct a representation of the information flow for the shivering response. Annotate your representation to include
$\bullet$ the sensory input
$\bullet$signal transmission to the hypothalamus
$\bullet$signal transmission from the hypothalamus to the somatic nervous system
$\bullet$transmission to muscle tissue
$\bullet$and output response.
Include in your annotation the negative feedback loop that is established.
B. Shivering occurs when you have a fever even though your body temperature has not fallen. Identify the component of the information flow represented above that can cause this effect and describe how the brain has integrated the immune system and nervous system to maintain homeostasis.
Thermogenesis from accelerated metabolism in adipose (fat) tissue is a non-shivering response to a cold stimulus. Using a neurotropic virus, investigators are able to trace the paths of nerves in animals. Neurons infected by virus can then be visualized by exposing the tissue to antibodies that can be stained or using dyes that fluoresce. Ryu and co-workers (Journal of Neuroscience, 35, 2015) used this technique to demonstrate communication between nerves of the sympathetic nervous system and nerves of the sensory nervous system innervating thermoreceptors that are sensitive to hot and cold.
C. Construct a representation of information flow and annotate the representation with labels for
$\bullet$signal input caused by low temperature
$\bullet$signal transmission through nerves of the sensory
system
$\bullet$transmission of signal from the sensory system to the sympathetic system
$\bullet$transmission to adipose cells
$\bullet$output response of cells.
Include in your annotation the negative feedback loop that is established.

Key Concepts

Set Point Regulation and Immune Integration

Set point regulation involves the adjustment of the temperature threshold maintained by the hypothalamus. During fever, immune system signals can reset this set point, triggering thermoregulatory responses like shivering even when the actual temperature is not below normal. This demonstrates the close integration of the immune system with neural control mechanisms to maintain overall homeostasis.

Sympathetic Nervous System and Non-Shivering Thermogenesis

The sympathetic nervous system plays a key role in non-shivering thermogenesis by transmitting signals that accelerate metabolic processes in tissues such as adipose tissue. This response increases heat production through enhanced metabolism without the need for muscle contractions, demonstrating the integration of neural and metabolic pathways in temperature regulation.

Sensory Integration in the Hypothalamus

Sensory integration in the hypothalamus involves the processing and comparison of incoming temperature signals received from peripheral receptors with the body's set point. This integration is crucial for determining when corrective actions, such as shivering or metabolic adjustments, should be activated to restore the optimal temperature.

Somatic Nervous System Motor Activation

The somatic nervous system is responsible for transmitting signals from the brain to skeletal muscles to produce voluntary or reflexive movements. In the context of the shivering response, once the hypothalamus decides that heat generation is needed, it activates the somatic nervous system to stimulate muscle contractions that generate heat.

Negative Feedback Mechanism

A negative feedback mechanism is a control system in which a change in a variable triggers responses that counteract the initial change, thereby maintaining homeostasis. In the context of temperature regulation, when the body deviates from its set point, corrective signals are sent to reduce the discrepancy, such as inducing shivering to generate heat when the temperature is too low.

Thermoregulation

Thermoregulation is the physiological process by which an organism maintains its internal body temperature within a narrow, optimal range despite external temperature changes. This regulation is centrally controlled by neural circuits, particularly within the hypothalamus, which compares incoming temperature information with a predetermined set point to initiate corrective responses.

Reflex Arc

A reflex arc is the neural pathway that mediates a reflex action, typically involving a sensory receptor, an integrating center, and an effector organ. In thermoregulation, the detection of cold by peripheral thermoreceptors sends sensory input to the brain, which then transmits signals through neural circuits to initiate a motor response such as muscle contraction in shivering.

Transcript

00:01 So part a in this question is introducing how we're activating an action potential in neurons so that way the brain can perceive that action as a change in temperature.

00:13 Part b is going to be going on about how an agonist triggers the action potential.

00:19 And part c is going to go on how a single agonist activates multiple proteins to give a mix of signals.

00:27 So for part a, we start with the neuron.

00:29 It has a body, a long axon, and a terminal end.

00:38 The proteins that we're going to look at are going to be in the body of the neuron, and it's going to be placed inside the phospholipid bi layer.

00:52 So according to this, when a temperature change of 43 degrees activates on trpv1, what it's going to do is it's going to cause a conformational change where it's going to be no longer blocked and allow access for ions to get through.

01:16 If you remember, we have the sodium potassium pump, which pumps sodium outside of the cell.

01:23 So when you're opening proteins allowing ions to freely diffuse, sodium's going to be one of the main ions that comes back into the cell.

01:34 Since sodium is positively charged, the inside of the cell becomes slightly more positively charged.

01:40 When you get enough of those positively charged ions on the inside, you're going to depolarize the neuron and fire an action potential down to the axon terminal.

01:56 Depolarization is going to cause calcium exocytosis and neurotransmitter release into the space between neurons.

02:10 So when you have your neurotransmitters released, those are going to act on a different.

02:15 Neuron and eventually you keep chaining neurons until you get to the brain.

02:22 Since neurons are very specific based on say temperature or touch or some other sort of specific stimulus, this is going to be perceived as a temperature change and won't be confused with say a touch receptor or a stretch receptor.

02:39 It's very specific.

02:42 For part b, we have an agonist instead of just a temperature change.

02:46 So we have t -rpv -3 in the cell membrane.

02:57 Again, it's blocked just like the first protein...

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