Overview & Components of Connective Tissue
What are the three basic components of all connective tissue?
→ Cells, protein fibers, and ground substance (Slide 4)
What are the two major classes of connective tissue cells?
→ Resident cells and wandering cells (Slide 5)
What are the three types of protein fibers found in connective tissue?
→ Collagen, reticular, and elastic fibers (Slide 11)
What are the three types of loose connective tissue?
→ Areolar, adipose, and reticular connective tissue (Slide 22)
What are the three types of dense connective tissue?
→ Dense regular, dense irregular, and elastic connective tissue (Slide 26)
What are the three main categories of connective tissue?
→ Connective tissue proper, supporting connective tissue, and fluid connective tissue (Slide 20)
What vitamin deficiency causes scurvy, and what protein does it affect?
→ Vitamin C deficiency; affects collagen production (Slide 19)
What are three general functions of connective tissue?
→ Supports, protects, and binds organs (Slide 3)
Which resident cell is the most abundant in connective tissue proper and produces fibers and ground substance?
→ Fibroblasts (Slide 5)
Which type of connective tissue fiber is the strongest and most resistant to stretching?
→ Collagen fibers (Slide 11)
Which loose connective tissue is described as the body’s “packing material”?
→ Areolar connective tissue (Slide 22)
Which dense connective tissue type forms tendons and ligaments?
→ Dense regular connective tissue (Slide 27)
Which embryonic tissue gives rise to all adult connective tissues?
→ Mesenchyme (Slide 20)
Marfan syndrome is caused by a defect on which chromosome, and what tissue type does it primarily affect?
→ Chromosome 15; connective tissue (Slide 19)
Give two examples of connective tissues in the body.
→ Tendons, ligaments, adipose tissue, cartilage, bone, blood (Slide 3)
What resident cells function as embryonic stem cells for connective tissue repair and replacement?
→ Mesenchymal cells (Slide 6)
Which type of connective tissue fiber forms branching networks that provide structural support in lymph nodes and the spleen?
→ Reticular fibers (Slide 12)
What type of loose connective tissue is the major energy reserve of the body?
→ Adipose connective tissue (Slide 25)
Why does dense regular connective tissue heal slowly after injury?
→ It has few blood vessels, limiting nutrient and oxygen delivery for repair (Slide 27)
What are the two types of supporting connective tissue?
→ Cartilage and bone (Slide 30)
What are the three basic types of muscle tissue?
→ Skeletal, cardiac, smooth (Slide 40)
How do connective tissue fibers and ground substance together form the extracellular matrix (ECM)?
→ Protein fibers provide structure and strength, ground substance fills the space and supports cells, together creating ECM (Slide 4)
How do adipocytes differ in their role depending on whether they are scattered or in clusters?
→ Scattered adipocytes support other cells; clusters form adipose connective tissue for energy storage and cushioning (Slide 5)
What protein gives elastic fibers their ability to stretch and recoil?
→ Elastin (Slide 13)
What is the main function of reticular connective tissue?
→ Forms a supportive framework for many lymphatic organs (Slide 26)
Where in the body is dense irregular connective tissue commonly found?
→ Dermis of skin, periosteum of bone, perichondrium of cartilage, and organ capsules (Slide 28)
Which cartilage type is the most common in the body, and where is it found?
→ Hyaline cartilage; nose, trachea, larynx, costal cartilage, articular ends of long bones, most of fetal skeleton (Slide 32)
Which type of muscle tissue is voluntary and multinucleated?
→ Skeletal muscle (Slide 41)
Why is connective tissue considered the most diverse type of tissue in the body?
→ It has many specialized forms (e.g., bone, blood, fat) with varied structures and functions (Slide 3)
What is the role of fixed macrophages in connective tissue?
→ Phagocytize damaged cells or pathogens and release chemicals that activate the immune system (Slide 6)
Where in the body would you expect to find tissues rich in elastic fibers?
→ Skin, walls of arteries, and lungs (Slide 13)
Where in the body is areolar connective tissue commonly found?
→ Papillary layer of the dermis, subcutaneous layer, surrounding organs, nerves, and blood vessels (Slide 23)
How does the arrangement of collagen fibers differ between dense regular and dense irregular connective tissue?
→ Dense regular: fibers parallel, resist stress in one direction; Dense irregular: fibers clumped and random, resist stress in multiple directions (Slides 27–28)
Which cartilage type is strongest for weight-bearing and resists compression?
→ Fibrocartilage; found in intervertebral discs, pubic symphysis, menisci (Slide 33)
What type of cell is the functional unit of nervous tissue?
→ Neuron (Slide 44)
Explain how storage and transport are functions of connective tissue.
→ Adipose tissue stores energy; bone stores calcium and phosphorus; blood transports gases, nutrients, and wastes (Slides 17–18)
Which wandering cells secrete histamine and heparin, and what is their function?
→ Mast cells; histamine dilates blood vessels, heparin prevents clotting (Slide 8)
What is ground substance, and what role does it play in connective tissue?
→ A noncellular material produced by CT cells that supports and surrounds cells and fibers; determines tissue consistency (Slide 14)
What is the difference between white adipose tissue and brown adipose tissue?
→ White adipose stores energy, insulates, cushions; brown adipose generates heat in newborns, largely lost with age (Slide 25)
What is the primary function of elastic connective tissue?
→ Allows tissues to stretch and recoil (Slide 29)
What makes elastic cartilage different from hyaline cartilage?
→ Elastic fibers give flexibility and resilience; found in ear and epiglottis (Slide 34)
Define hypertrophy, hyperplasia, and atrophy.
→ Hypertrophy: increase in cell size; Hyperplasia: increase in cell number; Atrophy: decrease in cell size/number (Slide 46)
Compare how connective tissue provides both protection and immune defense.
→ Protection: bones protect organs, adipose cushions; Immune defense: leukocytes and ECM limit pathogen spread (Slides 17–18)
Plasma cells develop from B-lymphocytes. What is their function in connective tissue?
→ They produce antibodies that immobilize or neutralize foreign materials (Slide 8)
What are glycosaminoglycans (GAGs), and how do they contribute to ground substance function?
→ Negatively charged, hydrophilic molecules that attract cations and water, giving ground substance a gel-like property (Slide 15)
Why does weight gain occur if the number of adipocytes does not increase significantly?
→ Because adipocytes enlarge or shrink depending on fat storage rather than increasing in number (Slide 25)
Give two locations in the body where elastic connective tissue is found.
→ Walls of large arteries, trachea, vocal cords (Slide 29)
Describe the two types of bone tissue and their structures.
→ Compact bone: osteons, concentric lamellae, central canal for vessels/nerves. Spongy bone: lattice-like structure, lightweight but strong (Slide 36)
What is metaplasia, and give an example.
→ Abnormal change from one mature epithelium to another; e.g., smoker’s trachea: pseudostratified columnar → stratified squamous (Slide 47)
Why is connective tissue considered essential for structural integration of the body?
→ It links and supports other tissues, forms structural frameworks, and ensures organs and systems are interconnected (Slides 17–18)
Compare free macrophages to fixed macrophages.
→ Both phagocytize pathogens and debris, but free macrophages are mobile while fixed macrophages remain stationary (Slides 6, 9)
How do ground substance and protein fibers together determine the physical properties of connective tissue?
→ The ratio of fibers to ground substance determines whether CT is rigid (bone), flexible (cartilage), or fluid (blood) (Slides 14–15)
Compare the extracellular matrix of areolar and reticular connective tissues.
→ Areolar: loosely organized collagen and elastic fibers with abundant ground substance; Reticular: dense meshwork of reticular fibers forming supportive scaffolding (Slides 23, 26)
Compare the vascularity of dense regular and dense irregular connective tissues.
→ Dense regular: poor blood supply, slow healing; Dense irregular: extensive blood supply, faster repair (Slides 27–28)
What functions do bones serve besides structural support?
→ Mineral storage (Ca, P), hemopoiesis (blood cell formation), organ protection, movement levers (Slide 37)
What is dysplasia, and why is it clinically significant?
→ Abnormal tissue development, often precancerous, requiring monitoring (Slide 48)
A patient with scurvy cannot properly form collagen. Which connective tissue functions would be most directly impaired, and why?
→ Structural support and strength → collagen fibers are required for tensile strength; without them, tissues weaken (Slide 19, Supplemental)
A patient has low T-lymphocyte counts. How would this impair the connective tissue’s function?
→ Reduced ability to attack and eliminate foreign materials, weakening immune defense in tissues (Slide 9)
A mutation prevents the production of collagen fibers. How would this affect connective tissue structure and function?
→ CT would lose tensile strength, becoming weak and unable to resist stretching, leading to fragile tissues (Slide 11, Supplemental)
Predict what would happen to immune function if reticular connective tissue were destroyed.
→ Lymphatic organs like spleen, lymph nodes, and bone marrow would lose structural support, impairing immune cell storage and filtering (Slide 26)
Predict what would happen to joint stability if tendons and ligaments were made of dense irregular connective tissue instead of dense regular.
→ Joints would lose directional stability, as fibers would not align with pull forces, leading to frequent dislocations (Slide 27)
Why does cartilage heal more slowly than bone?
→ Cartilage is avascular, relying on diffusion for nutrient supply, while bone has extensive vascularization (Slide 31)
How does neoplasia differ from dysplasia, and what is the difference between benign and malignant growths?
→ Neoplasia: uncontrolled abnormal growth forming tumors; Benign: localized, non-spreading; Malignant: spreads and invades tissues (Slide 49)
How does the extracellular matrix composition differ between adipose tissue and bone, and how does this relate to their functions?
→ Adipose: minimal fibers, abundant cells for energy storage; Bone: mineralized ECM for rigidity, support, and calcium storage (Slides 3–4, 17–18)
Why are neutrophils considered part of connective tissue defense, and how do they act differently than macrophages?
→ Neutrophils specialize in attacking bacteria quickly, while macrophages provide longer-term defense and signal other immune cells (Slide 9)
Predict the functional consequences of excessive elastic fiber production in the walls of arteries.
→ Arteries would become overly stretchy and fail to maintain blood pressure, risking aneurysm or collapse (Slide 13, Supplemental)
Explain how brown fat in newborns supports survival, and why adults largely lack it.
→ Brown fat generates heat through high mitochondrial activity, helping newborns maintain body temperature; adults lose most brown fat as metabolic needs change (Slide 25)
Why is elastic connective tissue critical for arteries, and what condition might develop if it were absent or damaged?
→ Maintains arterial recoil during blood pressure changes; loss leads to rigid vessels and potential hypertension or aneurysm (Slide 29)
Compare the role of plasma in blood with lymph in fluid connective tissue.
→ Plasma: carries nutrients, gases, hormones, wastes; Lymph: derived from plasma, returns to circulation, balances fluid levels (Slides 38–39)
Why does necrosis trigger inflammation, and how can this lead to further tissue damage?
→ Cell contents spill into surrounding tissue → immune response → inflammation → secondary damage (Slide 50)
Imagine a tissue lacking protein fibers but rich in ground substance. Predict how it would perform compared to normal connective tissue.
→ It would have cushioning and space-filling properties but lack tensile strength and elasticity, making it weak structurally (Slides 4, 13–14)
Predict what would happen to connective tissue repair if mesenchymal cells lost their ability to divide.
→ CT would lose its stem cell population, impairing regeneration and slowing healing (Slide 6)
Compare the roles of collagen, reticular, and elastic fibers in supporting organ systems.
→ Collagen provides strength and resistance; reticular creates supportive frameworks; elastic allows flexibility and recoil (Slides 11–13)
If areolar connective tissue were absent, how would organ stability and nutrient exchange be affected?
→ Organs, nerves, and vessels would lack structural cushioning, vascular supply, and diffusion support, leading to instability and impaired nutrient delivery (Slide 23)
Compare dense regular, dense irregular, and elastic connective tissues in terms of their structure-function relationship.
→ Dense regular resists unidirectional stress, dense irregular resists multidirectional stress, elastic permits stretch/recoil—each specialized to tissue demands (Slides 26–29)
Predict the effect on the body if fibrocartilage were absent.
→ Weight-bearing joints like spine, pubic symphysis, and knees would lose shock absorption and compressive strength, leading to structural damage (Slide 33)
Compare the consequences of Marfan syndrome and scurvy on connective tissue integrity.
→ Marfan: genetic → weak ligaments, joints, aorta; Scurvy: nutritional → weak collagen → fragile tissues (Slides 19, 20)
Why does connective tissue’s diversity make it uniquely vulnerable to systemic disorders (e.g., autoimmune diseases, genetic collagen defects)?
→ Because connective tissue integrates and supports all organ systems, a defect in its ECM, fibers, or immune roles can disrupt multiple systems simultaneously (Slides 3–4, 17–18, Supplemental)
Explain how the balance of resident vs. wandering cells in connective tissue shifts during chronic inflammation.
→ Resident cells maintain ECM, but during inflammation, wandering cells (e.g., macrophages, lymphocytes) increase to fight pathogens, altering CT composition (Slides 5–10, Supplemental)
Why is the extracellular matrix composition (fibers + ground substance) a critical determinant in distinguishing different connective tissues?
→ Variations in fiber type, density, and ground substance consistency define CT’s mechanical properties and functions across tissues (Slides 11–15)
Compare how areolar, adipose, and reticular connective tissues together demonstrate the versatility of loose connective tissue.
→ Areolar cushions/supports, adipose stores energy and insulates, reticular scaffolds immune organs—showing structural, metabolic, and immune functions within one CT category (Slides 22–26)
Explain how the distribution of dense connective tissue types across the body reflects mechanical stress and physiological function.
→ Regular in tendons/ligaments (aligned forces), irregular in dermis/organs (multidirectional forces), elastic in arteries/trachea (constant stretching/recoil) (Slides 26–30)
Explain how connective tissue diversity (cartilage, bone, blood, lymph) demonstrates structural and functional specialization within one tissue class.
→ Cartilage: flexible support, Bone: rigid framework & mineral storage, Blood: transport, Lymph: fluid balance & immunity—all derived from mesenchyme but specialized for distinct roles (Slides 20–39)
Explain how tissue modifications such as hypertrophy, metaplasia, and neoplasia demonstrate the adaptability and vulnerability of tissues.
→ Show tissues can adapt to stress (hypertrophy), alter phenotype (metaplasia), or grow uncontrollably (neoplasia). These highlight both survival mechanisms and disease risks (Slides 46–49)