A.1.2.1 (3) Thermoregulation

What is thermoregulation?

the regulation of body temperature

What does it rely on?

cardiovascular, muscular, nervous, and integumentary systems

Where does all energy originate from?

the Sun

What is the core temperature?

temperature deep within the body

What is the shell temperature?

temperature near the body’s surface

What is the metabolic rate?

the amount of energy your body uses to perform basic functions

What is the relationship between metabolic rate and body temperature?

the higher the metabolic rate the more heat your body generates (proportional)

What are some factors that affect metabolic rate?

exercise, hormones, nervous system, body temperature, ingestion of food, age and sex

How is the core body temperature managed?

through the balance of between heat production and loss to the environment

How can heat be transferred away from the body?

conduction, convection, radiation and evaporation

What can an imbalance in body temperature lead to?

hyperthermia

What is hyperthermia?

an elevated body temperature usually above 39°C

Convection

heat transfer through the movements of fluids (air/water)

Sporting example of convection

cool breeze moving across your body carrying heat away, cooling you

Conduction

direct transfer of heat between two objects in contact

Sporting example of conduction

a swimmer, when in contact with the cooler water in a pool, heat is transferred from the body to the water regualting body temp during intense sessions

Radiation

transfer of heat through electromagnetic waves (without direct contact)

Sporting example of radiation

the body absorbing radiant heat when the environment temp is higher than body temp

Evaporation

heat loss when sweat (liquid) on the skin surfaces turns into vapor

Sporting example of evaporation

sweating when doing exercise, the evaporation from sweat cools you down as it removes heat

What are some other thermoregulatory mechanisms?

1. vasodilation

2. vasoconstriction

3. shivering thermogenesis

4. non-shivering thermogenesis

What is vasodilation?

widening of blood vessels to increase blood flow = helps release heat from the body

What is vasoconstriction?

narrowing of blood vessels to reduce blood flow conserving heat

What is shivering thermogenesis?

production of heat via involuntary muscle contractions (shivering)

What is non-shivering thermogenesis?

increasing metabolic processes in brown adipose tissue

How does a woman's menstrual cycle affect thermoregulation?

hormonal fluctuations during the menstrual cycle

What are the hormones involved in the thermoregulation of the menstrual cycle?

estrogen and progesterone

What happens during the follicular phase?

estrogen is dominant so body temperature is lower as it promotes vasodilation

What happens during the luteal phase?

progesterone is more dominant, raising the core temperature, sweating threshold increases

Diagram for thermoregulation and the menstrual cycle