Module 2 Muscle Growth And Development Flashcards
What is the normal process of increase in size produced by accretion of tissues similar in constitution to those of the original tissue or organ
Growth
How do animals grow?
Increase in height, length, girth, and weight. Size and weight of structural tissues increases
What is hypertrophy
Enlargement of existing cells
What is hyperplasia
Multiplication or production of new cells through mitosis or prenatally. No Change in cell size
What is accretionary growth
Increase in extra cellular material
What is true growth vs fattening
True growth is an increase in muscle tissue
What is net growth
Tissue synthesis minus tissue degradation
Growth is liner true or false
False
Why is growth not linear
Proteins turn over every 21 days
What is development
Gradually progressing from a lower complexity to a higher complexity
What is differentiation
Process by which cells and organs acquire completely individual characteristics.. progressive diversification of cells of embryo into muscle cells, brain cells, liver cells, etc
What is morphogenesis
Organization of various dividing cells into specific organs
What is maturation
Process of becoming fully developed and reaching the highest stage of complexity
What is senescence
When individual tissues and organ are no longer maintained in their mature form and undergo degenerative changes
What are the 3 phases of prenatal growth
Ovum, embryonic, prenatal/fetal
What is the ovum stage
Fertilization to gastrulation (when primary cell layers develop: ectoderm, mesoderm, and endoderm)
What is the embryonic stage
Differentiation of organs, tissues, and systems
When is the most prenatal growth
Last 1/3
What determines the length of gestation
Animal complexity
What is myogenesis
The molecular, biochemical, and morphological events that occur during the formation of muscle fibers
When does myogenesis occur
Prenatally
What type of cells does myogenesis form
Multinucleated muscle cells
What are myoblasts
Muscle precursor cells that fuse to form fibers
What is proliferated mitosis
Creation of daughter cells identical to parent cells
What are the steps of myogenesis
Multipotent stem cells undergo proliferation and differentiation, becoming myoblasts. Myoblasts line up and fuse forming a myotube, which forms muscle fibers
What type of cell growth occurs prenatal
Hyperplasia and hypertrophy
What kind of growth occurs postnallay
Only hypertrophy (no new cells after birth)
How do muscle fibers grow postnatally
Increase in length, adding sarcomeres to each myofibril
How to muscle cells grow postnatally
Increase in diameter, adding new myofibrils in each cell
What happens to the rate of myofibril growth over time?
Growth levels off
Fiber number is _____ at birth
Fixed
Hypertrophy results in increased:
Muscle cell size and weight
dna/protein ratio must remain constant in the cell during hypertrophy true or false
True
Why is more DNA needed for protein accumulation and cell growth?
The ratio must be constant
What must there be more of in order to provide extra DNA for hypertrophy cells
Nuclei
How is nuclei obtained for extra DNA for hypertrophy
Satellite cells
What are satellite cells
Non-fused myoblasts present in muscle cells after birth
What happens to satellite cells as animals age?
Decrease
What happens to growth when satellite cells decrease
Muscle growth is slower
What two things can increase muscle diameter
Fat cells and connective tissue
Where does termination of a muscle fiber occur?
Throughout the muscle, not just at the end
All muscle fibers are ______ at birth meaning they are:
Type 1: Red, with the most oxidation requirements
What happens to muscle fibers after birth?
Differentiation into White and intermediate types
Why do fibers differentiate into other types after birth?
Nerve influence and sequence of morphological changes experienced by developing fibers (exercise)
What is a fibroblast
Precursor cell to connective tissue, developing into tropocollagen, tropoelastin, and ground substance
Amount of connective tissue is related to:
Muscle function
Quality of collagen changes with:
Age (decreases with age)
Where would you find the most connective tissue: back or limbs?
Limbs
What gradually develops into lobes and lobules that are enclosed in collage our fibers and supplied with blood capillaries
Adipose tissue
What is an adipoblast
Starts to accumulate lipids
What is an adipocyte
Filled with lipid
Which is larger, adipoblast or adipocyte
Adipocyte
What is another term for visceral fats
Internal fats
What is KPH fat?
Visceral fats (Perirenal fat, pericardial fat, Mesenteric)
What is perirenal fat
Kidney fat
What is pericardial fat
Heart fat
What is mesenteric fat
Intestinal fat
What is subcutaneous fat
Just under the skin, fat used for yield grading, undesirable for cutability
What is Intermuscular fat
Fat between muscles, seam fat, undesirable for cutability
What is intramuscular fat
Fat within muscle, marbling, desirable for palatable to and quality grades
What is intracellular fat
Membrane phospholipids, most responsible for beef flavor development
What fat is the first deposited?
Internal fat
What is the first fat utilized
Intramuscular
Why do beef need fed for a long period
Marbling is deposited last
Growth of adipose tissue is highly _________ and depends on:
Variable: Genetics, calories fed
As fat percentage increases, what happens to moisture and protein?
Both decrease
What is the leanest gender for cattle
Bulls
What is the fattest gender for cattle
Heifers
What is the leanest gender for sheep?
Ram
What is the fattest gender for sheep?
Ewes
What is the leanest gender for hogs?
Boars
What is the fattest gender for hogs?
Barrows
