Physioreview56(Temperature Regulation)

Front 1

What structure regulates body temperature?

Back 1

Anterior hypothalamus

Front 2

How is body temperature regulated?

Back 2

CORE TEMPERATURE IS DETERMINED BY TEMPERATURE RECEPTORS ON THE SKIN AND IN THE HYPOTHALAMUS. This value is compared in the anterior hypothalamus with the set point temperature. If the core temperature is off from the set point, appropriate mechanisms are activated.

Front 3

What are the body's heat producing mechanisms and how do they work?

Back 3

1. Thyroid hormone: stimulates Na+-K+-ATPase to increase metabolic rate and produce heat
2. SNS: activates beta receptors in brown fat to increase metabolic rate and produce heat
3. Shivering: posterior hypothalamus activates alpha and gamma motoneurons causing a muscle contraction and heat production.

Front 4

What are the body's mechanisms to get rid of excess heat and how do they work?

Back 4

1. SNS: decreased tone to cutaneous blood vessels increases anteriovenous shunting of blood to venous plexuses close to the skin's surface and increases convection and radiation to produce heat loss(mediated by posterior hypothalamus)
2. Sweat glands: activated by sympathetic muscarinic receptors to produce heat loss by evaporation.

Front 5

What is a pyrogen?

Back 5

Substance that increases the body's set point temperature

Front 6

How is fever mediated through apyrogen?

Back 6

1. Pyrogens increase interleukin-1(IL-1) production
2. IL-1 stimulates the anterior hypothalamus tom produce prostaglandins
3. Prostaglandins raise the set point temperature

Front 7

Define heat exhaustion

Back 7

decreased blood pressure or syncope that develops from decreased blood volume due to excessive sweating.

Front 8

define heat stroke?

Back 8

Normal responses to increased ambient temperatures are impaired and core temperatures rises to the point of tissue damage

Front 9

Define malignant hyperthermia.

Back 9

Skeletal muscle produces excess heat through massive O2 consumption and causes a rapid rise in body temperature.

Front 10

What commonly used agents can cause malignant hyperthermia?

Back 10

Inhaled anesthetics

Front 11

What agent is used to reverse malignant hyperthermia?

Back 11

Dantrolene

Front 12

Define hyperthermia.

Back 12

Normal responses to low ambient temperature are insufficient to maintain core temperature near the set point.