Intro to Physiology and Homeostasis Flashcards
Define physiology.
Study of how structure and
function of the body work
together to allow behavioral
responses to the environment
What are some applications of animal physiology?
Understanding human health and diseases
* Agricultural production of animals for food
* Understanding invasive species
* Understanding environments/habitats and
interrelationships
What is the importance of environment with physiology?
Environment is often related to structure.
What are the 5 limitations environmental limitations discussed? Which is the most limiting?
- Temperature*
- pH
- Lack of water
- Radiation
- Light
What are the 3 limitations that affect animal physiology?
Environmental limitations
- Scaling limitations
- Evolutionary limitations
What is the biggest challenge for animals living in aquatic environments? Why?
Not having easy access to oxygen. Oxygen is 20x more available in air; extracting from water takes a lot of energy
What are 5 conditions animals living in aquatic environments are exposed to?
Wet all the time
Less light
More dense, more viscous
Oxygen is hard to extract
Abundant suspended nutrients
What factors are animals in terrestrial environments expose to?
Dry all the time (dehydration)
More light (easier to regulate temp)
Less dense, less viscous
Oxygen easier to extract
No suspended nutrients (need to actively seek out food)
What conditions make Earth optimal for life?
Carbon is very abundant and works optimally under the present planetary conditions
Water is the most abundant liquid molecule (though organisms did have to adapt to some drawbacks)
Light is plenitful
Averages temperatures allow for versatile organic covalent compounds
What happens when an object doubles in size?
- Its surface area (SA) increases by a factor of 4
- Its volume (V) increases by a factor of 8
- Its surface area to volume ratio decreases
Why does scaling matter?
The surface of organism is involved in exchange of material
with the environment while the volume is responsible for
the processing and use of these materials.
What is the difference in thermoregulation between large and small animals?
Small animals –
SA:V large, problems when
undercooling
Large animals –
SA:V small, problems when
overheating
How can evolution limit an animal’s physiology?
Diversity of adaptations to the environment is limited by ancestry
What is homeostasis?
The ability of organisms to maintain steady conditions internally despite environmental conditions. i.e., maintaining pH, chemical concentration, temperature, etc.
What is meant by homeostasis being dynamic?
The organs and organ systems within animals are constantly adjusting to any internal or external stages to maintain this steady state. It’s not a matter of this state just staying stable, but the body being able to regulate conditions as needed to maintain it.
What is the mechanism that maintains homeostasis?
Negative feedback
What is negative feedback?
A mechanism that aims to reduce a deviation from normal conditions in order to get things back within normal, livable ranges.
What are the basic components of a negative feedback system? What do they do?
A sensor/receptor that monitors a physiological value
The control centre, which compares values measured by the sensor to the normal range.
An effector that induces the change in order to reverse the situtation and return to the set point.
Can set point ever be altered?
set point may be altered in some instances. For example, during an infection, which results in a fever. This makes internal conditions unfavourable for bacterial
What is set point?
A set point is the value at which homeostasis aims to maintain.
What is thermoregulation?
The process that maintains homeostasis of temperature
Explain the difference between vasodilation and vasoconstriction in thermoregulation.
Vasodilation brings more blood and heat to the surface of the body, initiating radiation and evaporative heat loss, which helps cool the body. Vasoconstriction bring blood toward vital organs, conserving heat.
What is positive feedback?
A deviation from the normal range
results in more change, and the system
moves farther away from the normal
range.
What processes does positive feedback occur in?
Positive feedback occurs infrequently in biological systems but
is involved in important processes:
* the production of the action potential
* childbirth
* clot production
