Tissues - Connective Tissue Flashcards
What are the structural elements of CT?
- cells: widely separated, manufacture CT matrix
- matrix: determines properties of CT
What is the prefix for immature cells?
Blast
What is the prefix for mature cells?
Cyte
What are the types of connective tissue fibres?
Collagen
Elastic
Reticular fibres
Collagen fibres
- very strong
- high tensile strength (resistant to breaking under tension)
- slightly wavy appearance when not under tension, some give but not elastic
Elastic fibres
- finer than collagen
- capacity to stretch and recoil
Reticular fibres
- very fine form of collagen
- not visible in most photomicrographs
- forms supportive network/mesh
Dense connective tissue
- predominant fibre type is collagen
- fibre occupy more space than cells or ground substance
- cells are fibroblasts and fibrocytes (mostly)
Dense regular connective tissue
- fibres all aligned in same direction
- thick bundles of collagen
- not much stretch but bends
- poor blood supply
- fresh tissue is white
- found in ligaments and tendons
Dense irregular connective tissue
- same Elements as dense regular
- but fibres are arranged in many different directions
- examples: dermis of the skin
What can areola tissue convert to?
Adipose tissue
Adipose tissue
- aerolar CT that is modified to store fat droplets
- very well vascularised
- adipocytes
- very little matrix as cells occupy much space
What are the functions of adipose tissue?
- stores nutrients
- absorbs shock
- insulates
- holds some organs in place (structural fat)
Blood
- erythrocytes and leucocytes in plasma
- fibres are soluble in plasma and only evident during clotting
What is the function of blood?
- transport (O2, nutrients, waste , hormones)
- protection (WBC, platelets, antibodies)
- regulation (pH, body temp, fluid distribution)
What are the three types of cartilage?
Hyalin
Elastic
Fibrocartilage
What is cartilage intermediate between?
Dense CT and Bone
What are the cells of cartilage called?
Chondroblasts and Chondrocytes
What is most cartilage covered by?
Periochondrium (dense irregular CT)
What is the function of cartilage?
Provides shape and support
Template form bone growth
Resists compressive forces
Where is hyalin cartilage located?
Synovial joints, trachea, growth zones of skeleton
Where is elastic cartilage located?
Epiglottis, external ear
Where is fibrocartliage located?
Pubic symphysis, intervertebral discs
What do chondroblasts do?
Actively deposit matrix
What do chondrocytes do?
Maintenance
What is an epiphyseal line?
Mature, represents bony joint
What is an epiphyseal plate?
Growing (made of cartilage)
Is cartilage vascular or avascular?
Avascular - limit to thickness
Characteristics of loose areolar CT
- all 3 fibre types and fibrocytes (+ macrophages, WBC, adipocytes)
- abundance of reticular fibres
- fibres run in multiple direction allows for movement in many directions
- ground substance is semi-fluid/gelatinous
What is bone made up of?
1/3 organic: collagen fibres + protein and carbohydrate complexes
2/3 inorganic: calcium salts
What do calcium salts do in bone?
Give ridgidity
What does collagen did in bone?
Resistance to bending and twisting forces (in its absence bone will shatter)l
What are the types of cells in bone?
Osteoblasts: lay down bone tissue, non mitotic
Osteocytes: maintenance, remodelling
Characteristics of compact bone
Osteon: concentric rings of bone Highly vascular Concentric lamellae: inner layer Circumferential layer: outer layer - collagen fibres alternate directions to resist breaking in many directions
How are osteocytes nourished?
Nourished by diffusion
- facilitated by gap junctions between cells
When are fibres produced?
G1 of cell cycle
Scurvy
Lack of vitamin C in the diet
Vitamin C is a co-factor for 2 enzymes crucial to collagen formation
Which connective tissue covers bone?
Periosteum (dense irregular CT)
What are the cells in cartilage?
Chondroblasts and chondrocytes
Cartilage is __________
Avascular, realises on diffusion
No nerve supply, good for covering joints
What is the function of loose areolar CT?
- widely distributed packing material of the body
- binds body parts but allows them to move freely over one another
What is the function of loose CT?
- provides a support mesh for cells in delicate, cellular organs like liver, spleen, bone marrow and lymph nodes
