Question

Analyze and discuss the function of temperature regulation in the body. Examine the benefits of fever and demonstrate how to explain these to a worried family member. Examine the different types of noxious stimuli and compare and contrast the ways the four nociception phases might address these stimuli differently. Discuss the current progress of the development of cannabinoid receptor agonists without side effects.

Answer 1

Analyze and discuss the function of temperature regulation in the body.

Thermoregulation is the body’s physiological function of heat regulation to maintain a constant internal body temperature. The heat of the body is measured in units called degrees.The “core” internal temperature of 98.6° Fahrenheit (F) (37° centigrade [C]) does not vary morethan 1.4°F (0.77°C) and is higher than the skin andexternal temperature. In contrast, the skin temperature rises and falls in accordance with changes in environmental temperature.

Heat Production

• Heat is produced in the body’s cells through food metabolism that results in the release of energy. The body converts energy supplied by metabolized nutrients to energy forms that can be used directly by the body. One form of this energy is thermal energy for regulation of body temperature. Energy is measured in terms of heat. A kilocalorie is an energy value (heat measure) of a given food; 1 kilocalorie equals 1000 calories (the amount of heat required to raise the temperature of 1 kilogram of water 1°C). This type of heat liberation is usually expressed as the metabolic rate and measured as the basal metabolic rate, or BMR (the rate of energy use in the body needed to maintain essential activities).
• Body temperature is controlled by balancing metabolic heat production with heat loss. Most heat production comes from the deep tissue organs (brain, liver, and heart) and the skeletal muscles. The skin, subcutaneous tissues, and fat of the subcutaneous tissues serve as heat insulators for the body. Sweat glands in the dermis are innervated by sympathetic nerves of the autonomic nervous system and are controlled by the anterior hypothalamus to regulate sweating.
• When body heat rises, the hypothalamus transmits impulses to reduce body heat by triggering perspiring, vasodilation (the widening of blood vessels), and the nhibition of heat production. The opposite physiological functioning occurs in response to a decrease in body heat. In this situation the hypothalamus transmits impulses to stimulate heat production through vasoconstriction (the narrowing of blood vessels), muscle shivering, and piloerection (hairs standing on end).

Heat Loss

Most body heat is lost from the skin’s surface to the environment by the processes of radiation, conduction, convection,and evaporation

Examine the benefits of fever and demonstrate how to explain these to a worried family member.

• Fever stimulates immunity system
• it will strength our body
• As temperature of body increases, it will kill the microbes in the body

Examine the different types of noxious stimuli

Noxious stimuli are those events/ stimuli that damage tissues

They are of mechanical stimuli(Eg- Tissue deformation), chemical stimuli(acid exposures/chemical irritant), thermal stimuli(hyperthermia)

Phases of nociception

The four fundamental processes involved in nociception (process by which individual becomes consciously aware of pain) are as follows

• Transduction—The changing of noxious stimuli in sensory nerve endings to energy impulses

• Transmission—Movement of impulses from site of origin to the brain

• Perception—Developing conscious awareness of pain

• Modulation—The changing of pain impulses

Transduction of Pain

When noxious stimuli occur, tissues are damaged. Celldamage releases the following sensitizing substances:

• Prostaglandins (PG)

• Bradykinin (BK)

• Serotonin (5HT)

• Substance P (SP)

• Histamine (H)

Release of these substances alters the electrical charge on the neuronal membrane. This change in electrical charge is a result of movement of Na+ and other ions into the cells. The impulse is then ready to be transmitted along the nociceptor fibers.

Transmission of Pain

The specific action of pain varies depending on the type of pain. In cutaneous pain, cutaneous nerve transmissions travel through a reflex arc from the nerve ending (point of pain) to the brain at a speed of approximately 300 feet per second, with a reflex response causing an almost immediate reaction. This explains why, when a hot stove is touched, the person’s hand jerks back before there is conscious awareness that damage is occurring. After a hot stove is touched, a sensory nerve ending in the skin of the finger initiates nerve transmission that travels through the dorsal root ganglion to the dorsal horn in the gray matter of the spinal cord. From there, the impulse travels though an interneuron that synapses with a motor neuron, which exits the spinal cord at the same level. This motor neuron, and the stimulation of the muscle it innervates, is responsible for the swift movement of the hand away from the hot stove. In the case of the hot stove, the sensory neuron synapses not only with an interneuron but also with an afferent sensory neuron. The impulse travels up the spinal cord to the thalamus, where a final synapse conducts the impulse to the cortex of the brain. Efferent or descending motor neuron response is conducted from the brain through the spinal cord, where it synapses with a motor neuron that exits the spinal cord and innervates the muscle.

In visceral pain, transmission of pain impulses is slower and less localized than in cutaneous pain. The internal organs (including the gastrointestinal tract) have a minimal number of nociceptors, which explains why visceral pain is poorly localized and is felt as a dull aching or throbbing sensation. However, internal organs have extreme sensitivity to distension.

Pain Perception

When the impulse has been transmitted to the cortex and is interpreted by the brain, the information is available on a conscious level. It is then that the person becomes aware of the intensity, location, and quality of pain. This information is interpreted in light of previous experience, adding the affective component to the pain experience.

Modulation

Modulation refers to activation of descending neural pathways that inhibit transmission of pain. “The pathways are described as descending because they involve neurons originating in the brain stem that descend to the dorsal horn of the spinal cord”