Whole Body Animal Growth Flashcards
(40 cards)
What are the different types of growth curves?
Cumulative growth curve, absolute growth rate curve, and relative growth rate curve
Which growth curve is the sigmoidal curve (s-curve) found? How is it shaped?
- Found in the cumulative growth curve
- Shaped like the letter “s” and is really stair-stepped due to sporadic growth spurts
How useful are cumulative growth curves?
They are useful to compare growth between animals BUT are not easy to interpret to determine the period of maximum growth (aka point of inflection).
Name the features of a cumulative growth curve.
- Self-accelerating phase
- Point of inflection
- Self-retarding phase
- Asymptote
What is prenatal growth?
It is the growth rate at early stages.
What is the self-accelerating phase?
The period of time in which an animal has reached a level of complexity that enables it to grow rapidly
What are the characteristics of the self-accelerating phase?
1) Characterized by exponential growth
2) Velocity of growth is continued by more and more cell dividing and hypertrophy
3) Results in rapid growth with little increase in complexity
In the self-accelerating phase, how does the growth become linear (“almost to 1”)?
When the acceleration force is in balance with the counteracting effects of increased complexity and limited nutrients, growth becomes linear!
What is the point of inflection?
It is the point of maximum growth velocity after which the animal will continue growing but at a decreasing rate
What is maximum growth velocity?
Period of greatest average daily gain
When does the point of inflection occur?
The point of inflection occurs during puberty in many species.
It’s the time point when the maximum number of construction workers can simultaneously expand our house
What is the self-retarding phase?
It’s the phase where an animal approaches mature weight at a decreasing rate of growth.
We’re still adding to our house, but at a much slower rate.
In the self-retarding phase, what gradually diminishes?
Gradually diminishes the increase in food intake until energy consumed approaches maintenance requirements.
In the self-retarding phase, what is the reduced growth rate controlled by?
Reduced growth rate is controlled by many signals, including the secretion of somatostatin by the hypothalamus.
What is maturity described as a point on a graph?
Point at which food intake matches maintenance requirements
What is maturity regarded as?
Regarded as mature body weight
Does maturity fluctuate throughout life? If so, what does it depend on?
Yes, maturity fluctuates throughout life depending on available food, reproductive cycle, and environmental stress.
What is another way to illustrate the phases of growth?
To divide the postnatal growth curve into four phases: Phase I, Phase II, Phase III, and Phase IV
Tell me the general characteristics regarding % total growth, tissues of growth, and growth speed in Phase I of the postnatal growth curve.
- % Total Growth = 15-20%
- Tissues of Growth = All tissues
- Growth Speed = rapid
Tell me the general characteristics regarding % total growth, tissues of growth, and growth speed in Phase II of the postnatal growth curve.
- % Total Growth = 75%
- Tissues of Growth = Bone, muscle, less fat
- Growth Speed = very rapid
Tell me the general characteristics regarding % total growth, tissues of growth, and growth speed in Phase III of the postnatal growth curve.
- % Total Growth = 80-90%
- Tissues of Growth = fat
- Growth Speed = slow
Tell me the general characteristics regarding % total growth, tissues of growth, and growth speed in Phase IV of the postnatal growth curve.
- % Total Growth = 95%
- Tissues of Growth = fat
- Growth Speed = very slow
What is the chronological age?
Age in absolute time units (days, months, years)
True or False: Animals within a species, breed, or gender DO grow, develop, or fatten at the same rate or mature at the same chronological age.
FALSE - Animals within a species, breed, or gender DO NOT grow, develop, or fatten at the same rate or mature at the same chronological age.
