What is Growth?
An increase in size without changing compostion.
Example: Small liver cells still function the same as large liver cells.
Cells growing larger in size
An increase in cell number.
Usually occurs at a very young age, often before the animal is born.
Increase in material around cells.
Increase in complexity.
- Example: 8-cell embryo development. Simple form -> more complex form.
Why is meat so highly desired by consumers?
- 1. High quality protein
- 2. Good iron source
- 3. Good source of B vitamins
What is the feed conversion ADG?
- should it be high or low?
Average Daily gain. Growth/Day
What is the feed conversion for feed efficiency?
- should it be high or low?
How can growth and development be improved?
- 1. Nutrition
- 2. Genetics
- 3. Other additives
- - implants, hormones, vitamins, minerals
List the 4 tissue structures
- 1. Muscle
- 2. Connective
- 3. Nervous
- 4. Epithelium
Describe epithelium tissue
- - thin layer of cells covering free surfaces in the body.
- - Simple or stratified
Describe Connective tissue
-Holds parts of the body together
List the types of connective tissue
- 1. Blood and lymph
- 2. Bone and cartilage
- 3. Adipose (fat)
- 4. Connective tissue proper
What is contained in connective tissue proper?
- 1. Collagen
- 2. Elastin
- 3. Reticulin
- 4. Ground Substance
Name the two ingredients in Ground Substance
- Glycosalaminoglycans and proteoglycans
- - also known as synovial fluid
Forms of connective tissue
Dense: bone, cartilage, ligaments, tendons
Lose: organ framework, blood vessels, muscle sheets
Describe ground substance
- - viscous clear fluid
- - contains glycoprotein (protein + cartilage)
- - Contains glycoaminoglycans (hyaluronic acid)
- -chondroitin sulfates (cartilage and tendons)
What are extracellular fibers?
- - can be dense or lose
- - contain collagen and elsastin
- colagen is most abundant at 20-30% of the bodies protein and influences meat tenderness.
Describe the connective tissue adipose.
- Contains: fibroblasts and adipocytes
- Used for body temp regulation
- Energy storage
- Endocrine function
- Protection of major organs
- Composition: 76-94% lipid, 5-20% water, 1-4% protein
What is a fibroblast?
Precursor cell for multiple connective tissues
What is an adipocyte?
Mature fat cells that store triglycerides.
Describe the connective tissue, cartilage.
- Structural support for other tissues in the body
- Important for bone formation
- Chondrocytes are the main cells
- ECM (ground substance)
What are the types of cartilage?
Most abundant cartilage
resides on surfaces of bones and joints
and ventral side of ribs
Dorsal tips of vertebrae (buttons)
blue/white in color
- less transparent
- more flexible than hyaline
- matrix with branch elastic fibers
- Epiglotis (hangy down thin in throat) is made of this cartilage
Numerous collagenose fibers
At ends of tendons-bone connection
Within capsules and ligaments of joints
Bone connective tissue
- Most rigid of connective tissues
- made of cells, fibers, and calcified ECM
- for support and structure
- Protection for organs
- calcium, magnesium, sodium, and other ion storage
Long Bone structure
- Diaphysis: central shaft. Hollow center with marrow. Compact bone
- Epiphysis: both ends of diaphysis. Spongy bone inside. compact bone outside.
- Periosteum: Outside layer coating or membrane. Covers entire bone.
- Articular Cartilage: thin layer of hyaline. covers joint surfaces.
- Endosteum: Inner layer of diaphysis shaft.
- Epiphyseal plate: growth plate. between the epiphysis and diaphysis. Appears as cartilage in young animals, growth plate in mature.
Bone Cell Types
- Osteocytes: cell cavities within the calcified matrix.
- Osteoblast: Immature percursor cells. Mature into osteocytes
- Osteoclast: Mineral regulation. involves resorption (bone loss)