Lecture 3: Connective Tissue Flashcards
Describe the function of connective tissue in the body
Connective tissue binds, supports, and strengthens other body tissues, serves as a major transport system (e.g., blood), and acts as a site for stored energy reserves (e.g., adipose tissue).
Explain the vascularity of connective tissue compared to cartilage and tendons.
Connective tissue can be highly vascular, meaning it has a rich blood supply.
Except for cartilage, which is avascular.
And Tendons, which have very little blood supply.
Define the components of connective tissue.
Connective tissue is made of extracellular matrix (ECM) and cells.
How does the structure of the extracellular matrix (ECM) influence connective tissue properties?
The structure of the ECM largely dictates the qualities of connective tissue, such as the firmness of cartilage and the hardness of bone.
What is the composition of the extracellular matrix (ECM)?
The ECM is composed of ground substance and protein fibers.
Describe the components of ground substance in the extracellular matrix.
Ground substance is made of water, proteins, and polysaccharides.
Explain the role of glycosaminoglycans (GAGS) in connective tissue.
Glycosaminoglycans (GAGS), also known as mucopolysaccharides, are long unbranched polysaccharides that attract water, contributing to the jelly-like consistency of ground substance.
What are proteoglycans and how are they formed?
Proteoglycans are formed by the combination of core proteins and glycosaminoglycans (GAGS).
Describe the function of sulphated glycosaminoglycans in connective tissue.
Sulphated GAGs bind covalently with core proteins to form proteoglycans and help them bind with water.
What is the role of hyaluronic acid in connective tissue?
Hyaluronic acid is a viscous, slippery substance that lubricates joints and helps maintain the shape of the eyeball.
Explain the function of hyaluronidase.
Hyaluronidase is an enzyme produced by white blood cells, sperm, and some bacteria that dissolves hyaluronic acid, allowing easier movement through tissues.
What is aggrecan and how is it formed?
Aggrecan is a proteoglycan made of chondroitin sulfate and keratin sulfates, which becomes an aggregate when combined with hyaluronic acid.
Describe the differences between sulphated and non-sulphated glycosaminoglycans.
Sulphated GAGs bind with core proteins to form proteoglycans, while non-sulphated GAGs, like hyaluronic acid, do not bond directly with core proteins but to various Proteo-glycans
How do glycosaminoglycans contribute to the properties of ground substance?
Glycosaminoglycans are highly polar and attract water, which helps to create the jelly-like consistency of ground substance.
What is the repeating disaccharide unit in glycosaminoglycans?
The repeating disaccharide unit consists of an amino sugar (e.g., N-acetylglucosamine) and a uronic sugar (e.g., glucuronic acid).
What are proteoglycans composed of?
Proteoglycans are composed of a core protein and glycosaminoglycans (GAGs).
What is the role of sulphated GAGS?
Sulphated GAGS bind covalently with core proteins to form proteoglycans and help them bind with water.
Where is dermatan sulphate found?
Dermatan sulphate is found in skin, tendons, blood vessels, and heart valves.
What is heparin sulphate and where is it found?
Heparin sulphate is a type of sulphated GAG found in various tissues, including blood vessels.
What is keratin sulphate and where is it found?
Keratin sulphate is found in bone, cartilage, and the cornea of the eye.
What is the function of chondroitin sulphate?
Chondroitin sulphate supports and provides adhesive features of cartilage, bone, skin, and blood vessels.
What is exophthalmos and its association with thyroid disease?
Exophthalmos is an abnormal condition associated with autoimmune over-activation of the thyroid, leading to increased orbital contents due to the deposition of glycosaminoglycans and influx of water.
Who is most commonly affected by exophthalmos?
Exophthalmos is most common in younger women.
What are the characteristics of collagen fibres?
Collagen fibres are very strong and flexible, forming in parallel bundles to resist pulling forces. They vary in features based on different tissues.
Where is collagen commonly located?
Collagen is commonly found in bone, cartilage, tendons, and filaments.
What are reticular fibres and their function?
Reticular fibres are made of collagen coated with glycoproteins, providing strength and support, and forming part of the basement membrane.
What is the structure and function of elastic fibres?
Elastic fibres are thinner than collagen fibres, made of elastin surrounded by fibrillin, allowing them to stretch up to 150% without breaking. They provide strength and stability.
What is Marfan Syndrome and its genetic basis?
Marfan Syndrome is a hereditary defect in elastic fibres caused by a dominant mutation on a gene on chromosome 15 coding for fibrillin, leading to increased growth and potential cardiovascular issues.
What are some physical characteristics of individuals with Marfan Syndrome?
Individuals with Marfan Syndrome are usually tall, long-limbed, and may have a chest deformity, such as a protruding or collapsed sternum.
What is the prevalence of Marfan Syndrome?
Marfan Syndrome occurs in about 1 in 20,000 live births.
What are fibroblasts and their function?
Fibroblasts are cells that secrete components of the matrix, including protein fibres and ground substance, and are widely distributed in connective tissue.
What do adipocytes do and where are they located?
Adipocytes, or fat cells, store fat in the form of triglycerides and are located under the skin and around organs.
What are macrophages and their role in connective tissue?
Macrophages, also known as histiocytes, are phagocytic cells that help control sites of infection, inflammation, and injury.
What are some examples of fixed macrophages?
Examples of fixed macrophages include ‘dust cells’ in the lungs, ‘Kupffer cells’ in the liver, and ‘Langerhans cells’ in the skin.
What are the two types of marcophages?
Fixed and wandering Macrophages.
What are plasma cells and their function?
Plasma cells are activated B-lymphocytes that produce antibodies, primarily found in the gut, lung, salivary glands, lymph nodes, spleen, and bone marrow.
What is the role of mast cells in the body?
Mast cells produce histamine when bitten, which dilates blood vessels and increases their permeability, allowing for more surface area for blood flow.
Where are mast cells commonly located?
Mast cells are located alongside blood vessels.
What are leukocytes and their function?
Leukocytes, or white blood cells, such as neutrophils and eosinophils, migrate out of the blood into tissues to perform their functions.
What are the two classifications of connective tissue?
Connective tissue is classified into two main categories: embryonic and mature connective tissues.
What is mesenchyme and its significance?
Mesenchyme is an embryonic connective tissue that gives rise to all other connective tissues and consists of mesenchymal cells in a semi-fluid ground substance containing reticular fibres.
What is mucous connective tissue and its function?
Mucous connective tissue has widely scattered fibroblasts embedded in a jelly-like ground substance and supports the umbilical cord of the fetus.
What is areolar connective tissue and its characteristics?
Areolar connective tissue is the most common form of connective tissue, characterized by many cells and fewer fibres, providing strength, elasticity, and support.
What types of fibres are present in areolar connective tissue?
Areolar connective tissue contains three types of fibres: collagen, reticular, and elastic.
What is adipose connective tissue and its functions?
Adipose connective tissue is dominated by adipocytes, serving as an energy storage, insulation, and temperature control, found in areas like the buttocks, flanks, abdomen, and around the eyes.
What is the structure and function of reticular connective tissue?
Reticular connective tissue has a branched, mesh-like pattern due to the arrangement of reticular fibres, providing structural support in lymphoid organs such as the spleen, red bone marrow, and lymph nodes.
Where is reticular connective tissue located?
Reticular connective tissue is located in the bone marrow, Peyer’s patches, lymph nodes, kidneys, liver, and spleen.
What is dense regular connective tissue and its function?
Dense regular connective tissue has more fibres and fewer cells, with regularly arranged collagen, providing attachment for tendons (muscle to bone), ligaments (bone to bone), and aponeuroses (muscle to muscle). It has a shiny white colour and is slow healing.
What is dense irregular connective tissue and its characteristics?
Dense irregular connective tissue has more fibres and fewer cells, providing strength and making the skin resistant to tearing from stretching forces in different directions. It has fibers that are not arranged in parallel bundles and is found mostly in the reticular layer of the dermis.
What is dense elastic connective tissue and its function?
Dense elastic connective tissue has a parallel protein fiber structure with greater flexibility and recoil capabilities, found in the walls of blood vessels and respiratory passageways. It allows tissues to return to their original length after stretching.
What is hyaline cartilage and its characteristics?
Hyaline cartilage is abundant and relatively weak, with a resilient gel structure where fibres are present but not obvious. It is found in the anterior ends of ribs, respiratory cartilage (nose, trachea, bronchi), and ends of long bones, providing flexibility and movement.
What is elastic cartilage and its function?
Elastic cartilage is made up of specialized cartilage cells called chondrocytes organized into elastic fibers, providing support to parts of the body that need to bend and move. It can bounce back to its original shape after deformation.
What is fibrocartilage, and where is it found?
Fibrocartilage is a mixture of white fibrous and cartilaginous tissue, giving it strength and some elasticity. It is the only cartilage containing type I collagen in addition to type II. It is found in intervertebral disks and at ligament and tendon insertions, acting as a cushion to absorb compression forces.
What are the two main types of bone tissue?
Compact bone (cortical bone) and spongy bone (cancellous bone).
What are the characteristics and functions of compact bone?
Compact bone forms the outer layer of bones and the shaft of long bones. It contains osteons, stores calcium and phosphorus, and provides structural protection and support.
What are the characteristics and functions of spongy bone?
Spongy bone lacks osteons, has a porous structure, stores triglycerides (yellow marrow), and produces blood cells (red marrow).
What are the four cell types found in bone?
Osteogenic cells – Stem cells that develop into osteoblasts.
Osteoblasts – Bone-forming cells that lay down collagen and start mineralization.
Osteocytes – Mature bone cells that maintain bone tissue and facilitate nutrient exchange.
Osteoclasts – Large, multinucleated cells that break down bone for remodeling.
What are the four components of an osteon (Haversian system)?
Lamellae – Concentric rings of mineral salts (for hardness) and collagen (for tensile strength).
Lacunae – Small spaces between lamellae containing osteocytes.
Canaliculi – Minute canals that provide routes for oxygen, nutrients, and waste.
Central (Haversian) Canal – Contains blood vessels, lymph, and nerves.
What are the steps in bone remodeling and healing?
Osteoclasts reabsorb dead bone.
Chondroblasts lay down hyaline cartilage callus.
Osteoblasts lay down new bone.
Osteoclasts remodel the new bone.
What are the two main components of blood?
Blood consists of blood plasma (liquid extracellular matrix) and formed elements (red blood cells, white blood cells, and platelets).
What is the function of erythrocytes?
Erythrocytes (red blood cells) transport oxygen and carbon dioxide.
What are the types and functions of leukocytes (white blood cells)?
Neutrophils and monocytes (macrophages) – Phagocytic, engulf bacteria.
Basophils and mast cells – Release histamine, intensifying inflammatory response.
Eosinophils – Defend against parasitic worms and involved in allergic reactions.
Lymphocytes – Key players in immune response.
What is the function of platelets?
Platelets, derived from megakaryocytes in red marrow, are responsible for blood clotting.
Is CT found on body surfaces?
No
