growth & development Flashcards
development
coordination of all diverse processes until maturity is reached
- growth, cell differentiation, changes in body shape, form, & fx
- stem cells ➞ differentiated cells & fxs
- starts at fertilization
- growth of tissues/organs/organisms from hyperplasia & hypertrophy
- hyperplasia stops at birth for muscle & fat cells (no more ↑ in # ) ➞ grow with age by hypertrophy
- some addition of new adipose but growth is mainly by adding lipids
hyperplasia
multiplication of cells
hypertrophy
increase in cell size
growth
↑ in body weight until mature size
* conception to maturity
* ↑ in # & ↑ in size
* structural mass
factors affecting growth:
prenatal:
- litter size
- mother’s size & nutrition
- genetics
post-natal/pre-weaning:
- mother’s nutrition
- litter size (larger litter = less access to food)
- initial size & aggressiveness (if it can fight litter-mates for resources)
- exposure to disease/parasites
post-weaning:
- gender
- genetics
- nutrition
- disease/parasites
- social stress
- envir conditions
- social stress & envir conditions = human-controlled
prenatal growth & development
includes gametes, embryos, & fetus
* cells become grouped in appearance & fx: cells ➔ tissues ➔ organs ➔ systems ➔ organisms
* embryonic stage: conception ➔ organ formation
* fetal stage: organ formation ➔ birth
* most growth occurs later in fetal stage
* embryo development:
* zygote ➔ blastomere ➔ morula ➔ blastocyst ➔ inner cell mass + trophoblast
* trophoblast ➔ placenta
* inner cell mass (germ cells) ➔ organism
* ectoderm = outermost germ layer ➔ skin, nervous system, hair, brain
* mesoderm = middle of germ layers ➔ skeleton, muscle, kidney, heart, blood
* endoderm = innermost germ layer ➔ GI, lungs, bladder
* most important structures for animals’ survival develops first
ectoderm
- skin
- nervous system
- hair
- brain
mesoderm
- skeleton
- muscle
- kidney
- heart
- blood
endoderm
- GI
- lungs
- bladder
