Heat Regulation and Temperature

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Questions and Answers

What happens when the environmental temperature is higher than the body temperature?

Heat gain occurs in the body (correct)

Vasoconstriction occurs

Shivering occurs

Heat is lost from the body

What is the primary way the body loses heat through radiation?

Through direct conduction from the skin to objects

Through the gastrointestinal tract

Through electromagnetic ray radiation (correct)

Through the respiratory system

What is the term for the rapid involuntary contraction or twitching of the muscles during exposure to cold?

Thermogenesis

Vasoconstriction

Metabolic Reactions

Shivering (correct)

What is the percentage of heat lost from the body through conduction to air?

15% Signup and view all the answers

What happens when the temperature of the air adjacent to the skin equals the temperature of the skin?

No further heat loss occurs Signup and view all the answers

What is the primary organ system responsible for heat loss from the body?

Skin Signup and view all the answers

What is the primary location of the motor center for shivering?

Posterior hypothalamus Signup and view all the answers

What hormone stimulates the release of thyroid-stimulating hormone (TSH) from the pituitary gland?

Thyrotropic releasing hormone (TRH) Signup and view all the answers

What is the term for the process by which heat is produced in the body through metabolic activities induced by hormones?

Chemical thermogenesis Signup and view all the answers

What is the result of severe muscular activities during shivering?

Enormous heat production Signup and view all the answers

Which of the following hormones increases heat production by accelerating cellular metabolic activities?

Adrenaline Signup and view all the answers

What is the effect of increased sympathetic stimulation or circulating adrenaline and noradrenaline in the blood?

Rapid increase in cellular metabolism Signup and view all the answers

What is the primary function of vasodilation in thermoregulation?

To increase the rate of heat transfer to the skin Signup and view all the answers

What happens to heat production mechanisms when body temperature increases?

They are strongly inhibited Signup and view all the answers

What is the effect of vasoconstriction on blood flow to the skin when body temperature decreases?

It decreases blood flow to the skin Signup and view all the answers

What is the role of the preoptic area in thermoregulation?

It contains thermoreceptors that detect changes in body temperature Signup and view all the answers

What is the effect of increased sweat secretion on the body?

It promotes heat loss from the body Signup and view all the answers

What happens to the body's thermoregulatory mechanisms when body temperature decreases?

Heat loss is prevented, and heat production is promoted Signup and view all the answers

Study Notes

Heat Loss

Heat loss occurs when environmental temperature is less than body temperature.
Maximum heat is lost from the body through skin, and a small amount is lost through the respiratory system, kidney, and gastrointestinal tract.

Methods of Heat Loss

Conduction: 3% of heat is lost through direct conduct from the body to solid objects, and 15% is lost through conduction to air.
Radiation: 60% of heat is lost through radiation, transferring heat by infrared ray radiation from the body to other objects.

Thermogenesis (Heat Production)

Shivering: a primary motor center in the posterior hypothalamus is activated when body temperature is low, causing shivering and producing enormous heat.
Increased metabolic reactions: stimulated by sympathetic centers, secreting adrenaline and noradrenaline, which accelerate cellular metabolic activities and produce heat.
Thyrotropic releasing hormone (TRH) is released by the hypothalamus, stimulating the release of thyroid-stimulating hormone (TSH) and thyroxin (T4), which accelerates metabolic activities and increases heat production.

Chemical Thermogenesis

An increase in sympathetic stimulation or circulating adrenaline and noradrenaline in the blood can rapidly increase cellular metabolism, producing heat.
Chemical thermogenesis is the process of producing heat through metabolic activities induced by hormones.

Temperature Regulation

When blood with increased temperature passes through the hypothalamus, it stimulates thermoreceptors, promoting heat loss and preventing heat production.
Heat loss is promoted by:
- Vasodilation of skin blood vessels, increasing heat transfer to the skin.
- Increasing sweat secretion, losing water and heat from the skin.
Heat production is decreased by inhibiting mechanisms that cause excess heat production, such as shivering and chemical thermogenesis.

Temperature Decrease Mechanisms

When the body temperature decreases, the temperature control system institutes opposite procedures to bring it back to normal.
Prevention of heat loss is achieved by:
- Skin vasoconstriction throughout the body, decreasing blood flow to the skin and preventing heat loss.
Promotion of heat production is achieved by:
- Stimulating mechanisms that increase heat production, such as shivering and chemical thermogenesis.

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Description

This quiz tests your knowledge on how the body regulates its temperature, heat loss, and the effects of environmental temperature on the body. Learn about shivering, heat loss, and more!