Exam 3 - Growth (AI Flashcards)
What are the phases of whole animal growth described by sigmoidal growth curves?
Self-Accelerating Phase, Point of Inflection, Self-Inhibiting Phase, Asymptote
The sigmoidal growth curve is characterized by its ‘S’ shape.
What is the difference between Physiological age and Chronological age of an animal?
Physiological age refers to specific physical or chemical stages of maturity, while Chronological age is the age in absolute time units (days, months, years).
Physiological age can vary significantly among animals of the same species.
How do external factors alter growth patterns?
Factors such as nutrition, disease, stress, and activity level can influence growth patterns.
These factors can change the shape of the growth curve.
What are the three types of growth curves that can be calculated and plotted?
- Cumulative growth curves
- Absolute growth curves
- Relative growth curves
What did John Hammond observe about the components of growth?
He observed that body components that are physiologically more important develop first, and extremities complete their development first.
Hammond’s work laid the foundation for understanding growth proportions.
What does the formula Y = ax^b describe in Allometric growth?
Y = log weight of carcass or animal, a = constant, x = log weight of tissue or component, b = growth coefficient of tissue or component.
What does the slope ‘b’ indicate in Allometric growth?
If b > 1, tissue grows faster than the whole; if b < 1, tissue grows slower; if b = 1, tissue grows at the same rate as the whole.
This relates to the development stages of different tissues.
What is the significance of the Point of Inflection in growth curves?
It is the point of maximum growth velocity after which growth continues at a decreasing rate.
What is the Self-Accelerating Phase characterized by?
Characterized by exponential growth with each cell dividing at a constant rate.
This phase leads to rapid growth with little complexity.
What happens during the Self-Inhibiting Phase?
The animal approaches mature weight at a decreasing rate of growth, with a gradual decrease in food intake.
What is the Asymptote in growth terms?
The point at which food intake matches maintenance requirements and is regarded as mature body weight.
What defines Absolute growth?
Cumulative weight of muscle, bone, and fat over time, resembling cumulative sigmoidal growth curves.
How is Relative growth rate calculated?
RGR = (ln Y2 - ln Y1) / (t2 - t1)
ln represents the natural logarithm.
What did Hammond conclude about Allometric growth?
Allometric growth does not fully describe growth changes, as nutrition affects tissue priority during growth.
What are the main components of whole body growth?
- Muscle
- Fat
- Bone
- Organs
What does Absolute growth refer to?
Cumulative weight gain over time for muscle, bone, and fat.
What changes in tissue composition occur during growth?
Changes occur in water, protein, lipid, and ash content.
Each tissue has a different growth trajectory.
True or False: The maximum growth for each tissue occurs at the same time.
False.
Fill in the blank: The maximum growth velocity is the period of greatest average daily gain, occurring at the _______.
Point of Inflection.
What are the characteristics of Allometric growth?
It studies how body parts change in size as an animal develops, with proportional relationships between tissues and the whole body.
What are the early developing muscles identified in Allometric growth?
- Distal aspects of thoracic limbs
- Proximal thoracic and hind limb
What defines the Self-Decelerating Phase?
The rate of growth decreases as the animal approaches mature weight.
What is the relationship between growth and nutrition according to Hammond’s findings?
When nutrition is limiting, tissues have different priorities for nutrient allocation based on their developmental sequence.
What type of growth curves do weight changes of muscle, bone, and fat over time resemble?
Cumulative sigmoidal growth curves