Growth, Development, and Body Composition Flashcards
Define growth
an increase in body mass or physical size
How do we measure growth?
- weight
- height
- length
- body composition
How do we calculate average daily gain (ADG)?
W2-W1/T2-T1 (in days)
ex. A horse weighs 300 lbs, and 2 weeks later it weighs 342 lbs. What is the ADG for the horse?
342-300/14 = 3 lbs./day
What are the ways that growth occurs or changes?
Hyperplasia
Hypertrophy
Atrophy
Tumors
Define hyperplasia
increase in cell numbers (early, prenatal stages)
Define hypertrophy
increase in size of cells (after birth)
Define atrophy
when cells shrink
Define tumors
abnormal localized cell growth without normal control mechanisms
What are the stages of prenatal growth?
- Blastocyst: occurs after fertilization; nutrition is from uterine secretions and the egg itself
- Embryonic: cell differentiation into tissues and organs; very small increase in weight
- Fetal: major growth in weight and composition, nutrition is from maternal bloodstream
Describe the prenatal growth curve
an exponential positive growth
x axis: days after conception
y axis: body weight
What factors influence prenatal growth?
- Size of dam
- number of fetuses
- Implantation site in uterus (a more individual factor in growth)
- nutrition level of dam
- disease status of dam
- genetics
- sex of the animal
Describe the postnatal growth curve
sigmoid shape (tilted S)
x axis: time
y axis: weight
self accelerating: the initial exponential phase of growth
self-inhibiting: growth slows due to restraints
What is the function of thyroxin?
Thyroxin is produced by the thyroid gland and it targets general body tissues. It sets the metabolic rate
What is the function of insulin in terms of growth?
Insulin is produced by the pancreas and it targets body cells to promote division
What is the function of adrenal corticoids in terms of growth?
Adrenal corticoids are produced by the adrenal glands they target general body tissues.
Mineralocorticoids regulate concentrates of minerals, especially Na and K
Glucocorticoids help regulate carbohydrate conversions and metabolism
What hormones regulate growth of specific organs?
Thyrotropin
Adrenocorticotropic hormone
Gonadotropins (FSH and Lutenizing Hormone)
What is the function of thyrotropin?
Thyrotropin (aka thyroid stimulating hormone) is produced by the anterior pituitary gland and it targets the thyroid to stimulate secretions.
What is the function of adrenocorticotropic hormone?
ACTH is released by the anterior pituitary to target the adrenal glands to stimulate secretions.