Chapter 4 Part 2 Flashcards
Connective Tissue (Functions and Types)
-Functions of CT) Include binding, support, protection, insulation, sotoring reserve fuel, and transporting substances (blood)
-Four Main Classes Connective Tissue Proper Cartilage Bone Blood
Three Characteristics of Connective Tissue.
1) All have common embryonic origin) CT comes from tissue called mesenchyme
2) Degrees of Vascularity) range from avascular to very vascular.
3) Have Extracellular Matrix
Components of the Extracellular Matrix
- Ground Substance
- Fibers
- Cells
Ground Substance
-Unstructured material that fills the space between the cells and contains fibers.
Three components)
- Interstitial Fluid) Fluid Between Cells
- Cell Adhesion proteins) Glue for cell attachment
- Proteoglycans) Sugar proteins which can trap water. Affect viscosity of the matrix.
Two Types of CT cells (based on cell maturity)
Blast Cells) Baby Cells. Immature form of a cell that actively secretes ground substance and ECM fibers.
Cyte Cells) Mature Cells. Less active than Blast Cell. Maintains the health of the matrix.
Main Types of CT Cells
Fibroblasts/cytes) Found in connective tissue proper
Chondroblasts/cytes) found in Cartilage
Osteoblasts/cytes) Found in Bone
Blood) Exception. Immature cells are found in bone marrow.
Other Connective Tissue Types
- Fat Cells) Stores nutrients
- White blood cells) Tissue response to injury
- Mast Cells) Initiate local inflammatory response. secrete chemicals such as heparin (regulates other chemicals), histamine (makes capillaries leaky), proteases and other enzymes.
- Macrophages) Eat dead cells and microorganisms.
Connective Tissue Proper
-All connective tissue except bone, cartilage, and blood
Two types
- Loose Connective Tissue) Arelolar, Adipose, and Reticular.
- Dense Connective Tissue) Dense Regular, Dense Irregular, Elastic.
Loose Areolar Connective Tissue
- Most widespread CT.
- Supports/Binds other tissues (and Organs). Holds Body Fluid/ Fat. Defend against infection.
- Fibroblasts secrete mostly collagen fibers. These fibers are loose which means there is more ground substance.
Loose Adipose Connective Tissue.
- Cells are Adipocytes (fat cells). More Cells than Ground Substance. Nucleus appears pushed to the side. Two types
- White Fat) Nutrient Storage. Cells are tightly packed (little matrix). Very Vascular. Absorb Shock, insulate, and store energy
- Brown Fat) Uses its lipids rather than ATP to heat the bloodstream.
Loose Reticular Connective Tissue.
- Resembles areolar tissue but the fibers are thinner reticular fibers (thin collagen fibers).
- Fibroblast cells are called Reticular Cells they Secrete the reticular fibers
- Form a mesh like Stroma (skeleton) that acts as support for blood cells in lymph nodes, spleen, and bone marrow.
Dense Regular Connective Tissue.
- High Tensile Strength; can stretch and withstand tension.
- Made of closely packed thick collagen fibers. Fibers are wavy and parallel to each other. Fibers/ Ground surface are made by fibroblasts.
- Poorly Vascularized.
- EX: Tendons, Ligaments, Aponeuroses (Flat, sheetlike tendons that attach muscle to muscle or bones)
Dense Irregular Connective Tissue
- Same Elements as Regular CT, but bundles of collagen fibers are irregularly arranged.
- Means it resists tension from many directions.
- EX: Dermis, Fibrous joint capsules, Fibrous coverings of some organs.
Elastic Connective Tissue
- Contains Elastic Fibers.
- Found in artery walls which need to stretch
- Some ligaments like those in the vertebrae are very elastic.
Cartilage
- Chondroblasts) grow new cartilage. They produce a new matrix until the skeleton stops growing at the end of adolescence.
- Chondrocytes) Mature Cartilage Cells. Found in cavities called lacunae.
- 80% Water. Made of tough collagen fibers and sugar proteins
- Lacks Nerve Fibers and is Avascular. It receives nutrients from perichondrium (makes chondroblasts/cytes)
Hyaline Cartilage
- Most abundant type
- Flexible, supports and reinforces. Resists comprehensive stress.
- Found at the tips of long bones (articular cartilage) also at the tip of the nose.
- Forms growth plate of bones
Elastic Cartilage
- Similar to Hyaline but more elastic fibers.
- Found in ears and epiglottis.
Fibrocartliage
- Structurally in between Hyaline cartilage and Dense Regular Tissue.
- Has rows of Chondrocytes alternating with thick collagen fibers.
- Can withstand compression and tension. Found in places such as the knee and intervertebral discs where there is heavy pressure.
Bone
- Also known as Osseous Tissue.
- Supports/ Protects body structures. Stores fat and synthesizes blood cells.
- Has Collagen and inorganic calcium salts.
- Osteoblasts produce the matrix. Osteocytes maintain the Matrix. Organized into Osteons .
- Richly vascular and innervated.
Blood
- Weird connective tissue because it is a fluid. The matrix is blood plasma
- Contains Red blood cells, white blood cells, and platelets.
- Transport nutrients, wastes, gasses, and other substances.
Muscle Tissue.
- Very Vascular. Responsible for Movement.
- Made of actin and myosin proteins that are responsible for contraction.
- Three Types) Skeletal Muscle, Cardiac Muscle, and Smooth Muscle.
Skeletal Muscle.
- Attached to and causes movement of bones. Also called voluntary muscles.
- Cells are called muscle fibers. Appear Striated or banded. Contain more then one nuclei
Cardiac Muscle
- Found in the walls of the heart. Involuntary
- Have striations but cells have one nucleus.
- Cells have branches that can join other cardiac muscle cells. The joint where they connect is called a intercalated disc.
Smooth Muscle Tissue
- Found in walls of hollow organs (other than heart). Involuntary muscle
- Does not have striations
- Spindle shaped cells with one nucleus.
Nervous Tissue.
-Main Component of Nervous system. Regulates and controls the functions of the body
-Has Two specialized cells
Neurons) Specialized nerve cells that generate/transmit nerve impulses
Neuroglia (galil cells) support, insulate and protect neurons.
Covering and Lining Membranes
- Composed of two primary tissue types (an epithelial bound to underlying connective tissue proper layer).
- Considered simple organs
- Three types) Cutaneous, Mucous, and Serous membranes.
Cutaneous Membrane
- Another Name for the Skin.
- Made of keratinized top layer of stratified squamous epithelium (Epidermis) attached to a thick layer of dense irregular connective tissue (Dermis).
- Is a dry membrane.
Mucous Membranes
- Also called Mucosae. Line body cavities that are open to the exterior (Digestive, respiratory, urogenital)
- Moist membrane bathed in secretions (mucus or urine)
- Epithelial sheet lies on loose connective tissue called the lamina propria. May secrete mucus.
Serous Membrane.
- Found in closed ventral body cavities.
- Made of simple squamous epithelium (mesothelium) resting on thin areolar connective tissue.
Tissue Repair
-Occurs when body barriers are compromised. Inflammatory and Immune responses are activated which starts repair
-Two ways repair happens:
Regeneration) Same type of tissue repairs the original tissue which means the original function is restored
Fibrosis) Connective tissue replaces the original tissue. This means the original function is lost
Steps In Tissue Repair.
Step 1) Inflammation) Release of inflammatory chemicals causes dilation of blood vessels and increase blood vessel permeability. Blood starts clotting and a scab forms if exposed to air.
Step 2) Orgizination restores blood supply) Blood clot is replaced with granulation tissue (capillary rich). Epithelium regenerates with the help of collagen fibers.
Step 3) Regeneration and Fibrosis) Tissue matures and thickens. Begins to look like original
Regeneration capacity of tissues.
Extremely well) Epithelial, Bone, areolar connective, dense irregular, and blood forming tissue
Moderate) Smooth muscle, Dense regular connective tissue.
Weak) Skeletal muscles, cartlidge.
Virtually None) Cardiac and nervous (replaced with scar tissue)
Aging Tissues
-As we age tissue function decreases.
Fibers
- Hold components of the matrix. Three types
- Collagen) Strong fiber, does not stretch.
- Elastic Fibers) long thin elastin fibers that allow for stretch and recoil
- Reticular Fibers) Thinner branched fibers made of a thin collagen. Allow for more stretch than larger collagen molecules.
