BIOL 1030H Lecture Notes - Lecture 3: Adrenal Gland, Muscle Contraction, Mount Everest
26 Jun 2018
School
Department
Course
Professor
Chapter 35 and 38 (808,811-813)
Environmental changes
External
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Endogenous (self - imposed)
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Animals must deal with constatnly changing environments
The orgnaism must maintain a suitable internal environment
Homeostasis:
"The active regulation and maintenance, in animals, organs, or cells, of a stable
physiological state in the face of changing environmental conditions"
Skin temperature, breathing rate, heart rate, sweating and heat production
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What is so stable about homeostasis?
Some systems change greatly in order to buffer others from damaging change (most are
on the peripheral)
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Least variable systems are in the core
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If you keep your core constant, you'll be in homeostasis
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Not all systems are variable:
Nearly universal in all living things
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Allow animals to invade physiologically unfriendly environment
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Homeostasis is widespread
Homeostasis requires physiological control systems:
Sensors (touch receptors)
1.
Integrator/control centre (brain)
2.
Effectors (muscles, sweat glands)
3.
Essential components
All tied together in negative feedback loop
Sensor/control centre- thermostat
Effector- heater
Response- heat
Once the thermostat learns that it has reached the set point, the heat turns off
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Set point- 18 degrees
Heat, high altitude (low oxygen), cold temperatures
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Maintenance of steady state is complex in an unchanging environment
When the environment is continuosly change it has to regulate
Conformers (cannot maintain homeostasis) eg. Sea star- will allow its internal
environment to change
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Regulators (maintain homeostasis)
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Organisms fall into two categories when responding to environmental change:
Environmental change proceeds at different rates, and evokes different responses
Minute (even seconds) to hours ----> physiological adjustment
Homeostasis and Animal Nervous System
January 24, 2018
5:00 PM
Biology 1030 Page 1
Document Summary
The orgnaism must maintain a suitable internal environment. "the active regulation and maintenance, in animals, organs, or cells, of a stable physiological state in the face of changing environmental conditions" Skin temperature, breathing rate, heart rate, sweating and heat production. Some systems change greatly in order to buffer others from damaging change (most are on the peripheral) If you keep your core constant, you"ll be in homeostasis. Once the thermostat learns that it has reached the set point, the heat turns off. Maintenance of steady state is complex in an unchanging environment. When the environment is continuosly change it has to regulate. Organisms fall into two categories when responding to environmental change: Conformers (cannot maintain homeostasis) eg. sea star- will allow its internal environment to change. Environmental change proceeds at different rates, and evokes different responses. Minute (even seconds) to hours ----> physiological adjustment. Going from a dark room to bright sunlight- pupils will dilate (adjust)
