Chapter 12: Thermoregulation Flashcards
What is hyperthermia?
A state which the internal temperature rises above the set point
What is hypothermia?
A state in which the internal temperature drops below the set point
What is thermoregulation?
The process by which animals maintain their body temperature within a normal range
What is an endotherm?
An animal that retains heat generated by metabolic activity
What are some structural features of endotherms?
Insulation, brown adipose tissue and shape and size
How does brown adipose tissue keep animals warm?
It is richly endowed with blood vessels and mitochondria, it also insulates and helps generate metabolic heat
What are some behavioural responses to to extreme temperatures?
Huddling and shutting down in extreme conditions (torpor)
What is kleptothermy?
A form of thermoregulation in which an animal shares in the metabolic thermogenesis of another animal; its most common form is huddling
What is torpor?
A state of decreased pysiological activity, usually by a reduced body temperature and metabolic rate
What is hibernation?
A period of dormancy over long periods of cold condtitons (a long version of torpor)
What is aestivation?
Dormancy in some animals during periods of drought
What is vasodilation?
Dilation (widening) of blood vessels, particularly arteriols
What is vasoconstriction?
The constriction of blood vessels by the surrounding smooth muscle cells, which increases blood pressure and redirects blood flow away from the contricted vessel
What is counter-current heat exchange?
A current that fows in the opposite direction to another current. Blood traveling in arteries warms the blood returning in the veins
What is thermogenesis?
The process of heat production in organisms (shivering)
What is non-shivering thermogenesis?
An increase in the cellular metabolic rate in skeletal muscle and other tissues to increase heat production
What is the function of the hypothalamus in thermoregulation?
It acts as a thermostat for internal temperature, it is sensitive to the blood flowing through it and responds by sending messages to the appropriate effectors
What is the hypothalumus?
A region of the forebrain that coordinates the endocrine and nervous systems; it secretes hormones and releasing factors that regulate the anterior pituitary gland, controlling body temperature, thirst, hunger and other hemeostatic systems
What is an example of a response by the hypothalaumus at low temperatures?
It releases the hormone thyrotropin-releasing hormone (TRH), which activates the anterior gland to release thyroid-stimulating hormone (TSH) which then stimulates the thyroid gland to screte the hormone thyroxine
What is insulin?
A hormone produced by the pancreas that regulates the amount of glucose in the blood
What is glucagon?
A hormone produced in the pancreas that promotes the breakdown of glycogen to glucose in the liver
What is glycogen?
An important energy-storing polysaccharide in animals
