CH 5 Flashcards
What are the three components of connective tissue?
Cells, Protein fibers, and Ground Substance
Fibroblasts
produces fibers and ground substance
Adipocytes
lipid storages (fat cells)
Mesenchymal cells
type of stem cell that can divide to replace damaged cells
Fixed macrophages
Phagocytose (engulf) damaged cells or pathogens
What are wandering cells?
Immune cells that move through tissue
Free macrophages
mobile phagocytic cells
Lymphocytes
attack foreign material
Mast cells
inhibit clotting and secrete histamine to dilate blood vessels
What is the function of protein fibers?
Strengthen and support the tissue
Collagen fibers
thick, unbranched fibers that are strong, flexible, and resistant to stretching
Reticular fibers
Thinner fibers that form a branching, interwoven framework
Elastic fibers
Branching, wavy fibers that stretch and recoil easily and contain elastin protein
What is ground substance?
Nonliving “background” material produced by connective tissue cells.
- Contains water and large hydrophilic molecules.
- GAGs, Proteoglycans, Glycoproteins
What are some functions of connective tissue CT?
- Physical protection: bones and adipose tissue
- Support and structural framework: bones and cartilage
- Storage: adipose tissue and bones (calcium and phosphorus)
- Binding of structures: tendons and ligaments
- Transport: blood
- Immune protection: wandering cells
Areolar connective tissue
Loose organization of collagen and elastic fibers.
- both fixed and wandering cells
- surrounds organs, nerve and muscle cells, and blood vessels.
LOOSE CT Proper
Adipose connective tissue
composed primarily of adipocytes filled with lipid droplets. - stores energy - insulates - cushions organs LOOSE CT Proper
Reticular connective tissue
Contains a meshwork of reticular fibers with fibroblasts and leukocytes.
- Forms framework of many organs (spleen, thymus, lymph nodes, and bone marrow)
LOOSE CT Proper
Loose Connective Tissue proper
Has abundant ground substance with fewer cells and protein fibers
Dense connective tissue proper
Mostly protein fibers with less ground substance and cells
Dense regular CT
tightly packed parallel collagen fibers
- found in placers with single-direction stress, such as tendons and ligaments
- has few blood vessels = takes a long time to heal
DENSE CT Proper
Dense irregular CT
Clumps of collagen fibers in all directions
- Provides support and resistance to stress in multiple directions
- Has extensive blood supply
DENSE CT Proper
Elastic CT
Contains branching, densely packed elastic fibers
- Has more fibroblasts than loose CT
- Able to stretch and recoil
DENSE CT Proper
Cartilage
Supporting CT
- Firm, semisolid ground substance with collagen and elastic fibers
- Strong, resilient and more flexible than bone.
- Found in areas of body that must withstand deformation
How are chondrocytes, lacunae, and perichondrium related?
Chondrocytes (cells) occupy small spaces called lacunae. These are then surrounded by a perichondrium.
What is unique about mature cartilage?
Avascular = has no blood vessels
Hyaline cartilage
Most common supporting CT type.
- Supports and cushions
- Clear, glassy appearance with scattered chondrocytes
- Firm matrix
Fibrocartilage
Weight bearing cartilage, resists compression
- protein fibers in irregular bundles between chondrocytes contribute to durability
- sparse amount of ground substance and few cells
- no perichondrium
Elastic cartilage
Flexible and springy
- numerous densely packed elastic fibers ensure tissue is flexible and resists deformation
- chondrocytes are closely packed
Endocrine glands
lack ducts and secrete hormones into the interstitial fluid or blood
- hormones act as chemical messengers that influence cell activity elsewhere
Exocrine glands
Form from epithelia and remain connected to the surface by ducts
- Sweat glands, mammary glands, salivary glands
Unicellular exocrine glands
Single cells located close to surface and do not have ducts
Merocrine glands
package secretions into vesicles and release them by exocytosis (e.g., salivary, some sweat) (merrily form vesicles to release secretion)
Apocrine glands
Pinch off a vesicle that contains the secretory product and release secretions by exocytosis (mammary glands!!) (a part of the cell is pinched off and becomes the secretion)
Holocrine glands
Accumulate product in a cell, which then disintegrates (Whole cell ruptures, dies, and becomes the secretion)
