The Animal Body (BOOK)
40.1
The endocrine- and the nervous system are two systems for coordinating and controlling responses
to stimuli. In the endocrine system, hormones are released by endocrine cells and released into the
bloodstream. Only cells with receptors for that hormone response the signal. In the nervous system
nerve impulses travel to target cells along communication lines
40.2
A regulator is an organism that regulate internal change in the face of external fluctuations, a
conformer allows its internal condition to change in accordance with external changes.
Homeostasis is regulated by negative- and positive feedbackloops.
homeostasis is sometimes altered by acclimatization, an physiological adjustment to changes in its
external environment.
40.3
Thermoregulation is the process by which animals maintain their body temperature within a normal
range.
Endothermic means that organisms are mostly warmed by heat generated by metabolism,
ectothermic means that organisms gain most of their heat from external sources.
An animal which body temperature varies with the environment is called poikilotherm, an animal
with a constant body temperature is called homeotherm.
Heat exchange can occur by radiation (emission of EM-waves), evaporation, convection (transfer of
heat by the movement of air or liquid) and conduction (transfer of thermal motion between
molecules of objects in contact with each other).
The integumentary system confess of the skin, hair and nails.
Blubber is a very thick layer of fat, just under the skin, which functions as insulation.
Vasodilation is the widening of superficial blood vessels, the reverse process is called
vasoconstriction. These two processes can regulate heat transfer to the environment.
Another approach to regulate/reduce heat loss relies on countercurrent exchange.
The ability of varying heat production is called thermogenesis.
Nonshivering thermogenesis is the process in which mitochondria increase their heat production
instead of producing ATP by increasing their metabolic activity. Some mammals have areas with extra
mitochondria which is called brown fat. These areas are specialized for rapid heat production.
In mammals, the sensors responsible for thermoregulation are concentrated in the hypothalamus,
which does also regulate the circadian clock.
40.1
The endocrine- and the nervous system are two systems for coordinating and controlling responses
to stimuli. In the endocrine system, hormones are released by endocrine cells and released into the
bloodstream. Only cells with receptors for that hormone response the signal. In the nervous system
nerve impulses travel to target cells along communication lines
40.2
A regulator is an organism that regulate internal change in the face of external fluctuations, a
conformer allows its internal condition to change in accordance with external changes.
Homeostasis is regulated by negative- and positive feedbackloops.
homeostasis is sometimes altered by acclimatization, an physiological adjustment to changes in its
external environment.
40.3
Thermoregulation is the process by which animals maintain their body temperature within a normal
range.
Endothermic means that organisms are mostly warmed by heat generated by metabolism,
ectothermic means that organisms gain most of their heat from external sources.
An animal which body temperature varies with the environment is called poikilotherm, an animal
with a constant body temperature is called homeotherm.
Heat exchange can occur by radiation (emission of EM-waves), evaporation, convection (transfer of
heat by the movement of air or liquid) and conduction (transfer of thermal motion between
molecules of objects in contact with each other).
The integumentary system confess of the skin, hair and nails.
Blubber is a very thick layer of fat, just under the skin, which functions as insulation.
Vasodilation is the widening of superficial blood vessels, the reverse process is called
vasoconstriction. These two processes can regulate heat transfer to the environment.
Another approach to regulate/reduce heat loss relies on countercurrent exchange.
The ability of varying heat production is called thermogenesis.
Nonshivering thermogenesis is the process in which mitochondria increase their heat production
instead of producing ATP by increasing their metabolic activity. Some mammals have areas with extra
mitochondria which is called brown fat. These areas are specialized for rapid heat production.
In mammals, the sensors responsible for thermoregulation are concentrated in the hypothalamus,
which does also regulate the circadian clock.
