Chapter 4 Review (7 questions) 1 short Flashcards
• What are tissues composed of?
Tissues are collections of cells and cell products that perform specific, limited functions
Four types of tissue
• What are the 4 types of tissue?
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Neural tissue
o What are the main functions of each type of tissue?
- Provide physical protection cover exposed surfaces
- Control permeability all substances that enter/leave the body cross an epithelium
- Provide sensation specialized epithelia facilitate smell, taste, sight, equilibrium, hearing
- Produce specialized secretions (glandular epithelium) sweat, mucus, oil, milk, hormones
• What are the 5 major characteristics of epithelia?
- Cellularity cell junctions
- Polarity apical and basal surfaces
- Attachment basement membrane or basal lamina
- Avascularity lack blood vessels
- Regeneration stem cells divide to replace lost cells
• How is epithelial integrity maintained?
- Intercellular connections
¥ Transmembrane proteins called CAMs (cell adhesion molecules) can connect adjacent membranes at cell junctions - Attachment to the basement membrane
¥ Hemidesmosome connects cytoskeleton of cell to the basement membrane - Epithelial maintenance and repair
¥ Cells are replaced by division of germinative cells (stem cells) near the basement membrane
• Describe the structure and function of tight & gap junctions, desmosomes, and hemidesmososmes.
- Tight junction seals plasma membranes between cells, prevents passage of water and solutes
- Gap junction connects cytoplasm of adjacent cells, allows rapid communication
- Desmosome connects cytoskeleton of adjacent cells, allows bending and twisting
¥ Hemidesmosome connects cytoskeleton of cell to the basement membrane
• How are epithelia classified?
- Based on cell shape
¥ Squamous epithelia thin and flat
¥ Cuboidal epithelia square shaped
¥ Columnar epithelia tall, slender rectangles - Based on number of cell layers
¥ Simple epithelium single layer of cells
¥ Stratified epithelium several layers of cells
o What functions are associated with each class of epithelia?
Squamous Epithelia
Simple squamous epithelium absorption and diffusion
¥ Mesothelium lines body cavities
¥ Endothelium lines heart and blood vessels
Stratified squamous epithelium
¥ Protects against physical and chemical wear and tear
¥ Keratin protein adds strength and water resistance to exposed body surfaces like the skin
Cuboidal Epithelia
Simple cuboidal epithelium
¥ Secretion and absorption
Stratified cuboidal epithelia
¥ Sweat ducts and mammary ducts
Transitional Epithelium
¥ Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage
¥ Appearance changes as stretching occurs
¥ Located in regions of the urinary system (ex: urinary bladder)
Columnar Epithelia
Simple columnar epithelium
¥ Absorption and secretion
Pseudostratified columnar epithelium
¥ Often have cilia fluid movement
Stratified columnar epithelium
¥ Protection
• How are endocrine and exocrine glands similar? How are they different?
Endocrine glands
¥ Release hormones into interstitial fluid
¥ No ducts
Exocrine glands
¥ Release secretions onto epithelial surfaces
• What are the 3 modes of secretion?
o How is the product secreted in each case?
- Merocrine secretion product released in vesicles (exocytosis) most common, ex: sweat glands
- Apocrine secretion product released by shedding cytoplasm, ex: mammary glands
- Holocrine secretion product released by cell bursting (killing gland cells), ex: sebaceous glands
• How are glands categorized?
¥ Unicellular glands
¥ Mucous (goblet) cells are the only unicellular exocrine glands
¥ Scattered among epithelia ex: in intestinal lining
¥ Multicellular glands
¥ Further classified by duct structure and shape
• What are the 3 major classes of connective tissue?
- Connective tissue proper loose and dense CT
¥ Connect and protect - Fluid connective tissues blood and lymph
¥ Transport, defense - Supporting connective tissues cartilage and bone
¥ Structure and strength
• How does the composition of the matrix influence the functions of each type of connective tissue?
¥ Establishing a structural framework for the body
¥ Transporting fluids and dissolved materials
¥ Protecting delicate organs
¥ Supporting, surrounding, and interconnecting other types of tissue
¥ Storing energy reserves, especially in the form of triglycerides
¥ Defending the body from invading microorganisms
• What is the main difference between loose and dense connective tissues?
Loose connective tissue
¥ More ground substance, fewer fibers
¥ Areolar tissue, adipose tissue, reticular tissue
Dense connective tissue
¥ More fibers, less ground substance
¥ Dense regular CT (includes elastic tissue) and dense irregular CT
• What cells are commonly found in connective tissue proper?
o What are their functions?
¥ Fibroblasts most abundant cell type, secrete proteins (ground substance viscosity, extracellular fibers)
¥ Fibrocytes second most abundant, maintain fibers
¥ Adipocytes store lipid droplets
¥ Mesenchymal cells stem cells, respond to damage by producing daughter cells that differentiate into other CT cells
¥ Macrophages, mast cells, lymphocytes, microphages cells perform diverse immune functions
¥ Melanocytes synthesize and store the brown pigment melanin
• What are the 3 types of fibrous proteins commonly found in connective tissue?
¥ Collagen fibers most common, structure is long, straight and unbranched, strong & flexible
¥ Reticular fibers network of interwoven fibers, stabilize positions of cells, blood vessels, nerves
¥ Elastic fibers branched and wavy, return to original length after stretching
• What types of connective tissue are present in embryos?
¥ Mesenchyme is the first connective tissue in embryos gives rise to all other connective tissues
¥ Adult connective tissues may contain scattered mesenchymal stem cells
¥ Are not found in adults
• What are the 3 types of loose connective tissue that are present in adults?
o What functions are associated with each type?
- Areolar least specialized, open structure with elastic fibers, highly vascularized
¥ ex: under skin - Adipose primarily contains adipocytes, padding, shock absorption, insulation
¥ ex: surrounds kidneys - Reticular complex network of fibers support functional cells (parenchyma)
¥ ex: liver
• What are the 3 types of dense connective tissue?
o What functions are associated with each type?
- Dense regular connective tissue parallel collagen fibers, absorb stress along one direction
¥ Ex: tendons and ligaments
Elastic tissue dense, regular structure dominated by elastic fibers
¥ Ex: elastic ligaments stabilize vertebrae - Dense irregular connective tissue no consistent pattern of fibers, absorb stresses from many directions
¥ Ex: layer under skin, organ capsules
• What are the 2 major types of supportive connective tissue?
o What functions are associated with each type?
Cartilage ¥ Gel-type ground substance ¥ For shock absorption and protection Bone ¥ Calcified (made rigid by calcium salts and other minerals) ¥ For weight support
• What is the structure of cartilage?
¥ No blood vessels (avascular) materials must diffuse through matrix
¥ Surrounded by perichondrium
¥ Outer, fibrous layer (for strength)
Inner, cellular layer (for growth and maintenance
• How can cartilage grow? (explain both mechanisms)
¥ Interstitial growth cartilage enlarges from within
¥ Chondrocytes in the matrix undergo cell division
¥ Most important during development (embryonic development through adolescence)
¥ Appositional growth new layers of cartilage are added to the surface
¥ Cells of the inner layer of the perichondrium undergo cell division then some differentiate into chondrocytes
¥ Rarely occurs in adults (in response to damage)
• What are the 3 types of cartilage?
o What functions are associated with each type?
- Hyaline cartilage stiff, flexible support, reduces friction between bones, most common
¥ Found in joints, rib tips, sternum, and trachea - Elastic cartilage supportive but bends easily
¥ Found in external ear and epiglottis - Fibrocartilage prevents bone-to-bone contact, resists compression, absorbs shock
¥ Pads knee joints, found between pubic bones and intervertebral discs
• What is the structure and function of bone?
What are membranes composed of?
Bone (Osseous Tissue)
¥ Strong (~⅔ of matrix is calcified calcium salt deposits)
¥ Resists shattering (flexible collagen fibers)
Bone Cells (Osteocytes)
¥ Arranged around central canals within matrix
¥ Small channels through matrix (canaliculi) allow access to blood supply
¥ Periosteum covers bone surfaces
¥ Contains outer fibrous layer and inner cellular layer
• What are the 4 types of membranes?
- Mucous membranes
- Serous membranes
- Cutaneous membrane
- Synovial membranes
o What is the relationship between the structure of each type of membrane and its function?
Mucous Membranes (Mucosae)
¥ Line passageways that have external connections
¥ In digestive, respiratory, urinary, and reproductive tracts
¥ Epithelial surfaces must be moist
¥ To reduce friction, to facilitate absorption and excretion
¥ Lamina propria (areolar CT)
Serous Membranes
¥ Line cavities not open to the outside, thin but strong
¥ Have fluid transudate to reduce friction
¥ Have a parietal portion covering the cavity; have a visceral portion (serosa) covering the organs
¥ Include pleura (covers lungs), peritoneum (covers abdominal organs), and pericardium (covers heart)
Cutaneous Membrane
¥ Is the skin, covers the surface of the body
¥ Thick, waterproof, and dry (keratin)
Synovial Membranes
¥ Line moving, articulating joint cavities, produce synovial fluid (lubricant)
¥ Protect the ends of bones
• What are the 3 types of fasciae?
o What is the function of each fascia?
- Superficial fascia layer of areolar and adipose tissue, separates skin from underlying tissues
- Deep fascia dense irregular CT, connects to capsules surrounding organs, perichondrium, periosteum, muscle tendons
- Subserous fascia areolar layer between deep fascia and serous membranes
• What are the 3 types of muscle tissue?
o What is the structure and function of each type?
- Skeletal muscle tissue
¥ Large body muscles responsible for movement - Cardiac muscle tissue
¥ Found only in the heart - Smooth muscle tissue
¥ Found in walls of hollow organs (blood vessels; urinary bladder; respiratory, digestive, and reproductive tracts)
o What are the characteristics of the cells of each type of muscle tissue?
Skeletal Muscle Cells
¥ Long (up to 1 ft) and thin usually called muscle fibers
¥ Multinucleate (several hundred)
¥ Do not divide new fibers produced by stem cells (myosatellite cells)
¥ Regulated by nerves also known as striated voluntary muscle
Cardiac Muscle Cells
¥ Called cardiocytes
¥ Limited ability for cell division and repair
¥ Form branching networks connected at intercalated discs
¥ Regulated by pacemaker cells striated involuntary muscle
Smooth Muscle Cells
¥ Small and tapered with single nucleus
¥ Can divide and regenerate
¥ No striations nonstriated involuntary muscle
• How is the organization of neural tissue in the body different from the other types of tissue?
¥ Specialized for conducting electrical impulses
¥ Rapidly senses internal or external environment
¥ Processes information and controls responses
¥ Neural tissue is concentrated in the central nervous system
¥ 98% of neural tissue is in the brain and spinal cord
• What 2 types of cells are classified as neural tissue?
o What is the function of each cell type?
- Neurons (nerve cells)
¥ Perform electrical communication - Neuroglia supporting cells
¥ Repair and supply nutrients to neurons
o How is the structure of a neuron specialized for communication?
¥ Cell body contains the nucleus and nucleolus
¥ Dendrites short branches extending from the cell body
¥ Receive incoming signals
¥ Axon (nerve fiber) long, thin extension of the cell body
¥ Carries outgoing electrical signals to their destination
• How do tissues respond to injuries?
¥ Cells restore homeostasis with two processes
- Inflammation
- Regeneration
o Which tissues can regenerate well?
¥ Epithelia and connective tissues regenerate well
• How do our tissues change as we age?
¥ Thinning epithelia and connective tissues
¥ Increased bruising and bone brittleness
¥ Joint pain and broken bones
¥ Cardiovascular disease
¥ Mental deterioration
• What is the relationship between age and cancer incidence?
¥ Cancer rates increase with age
¥ 25% of all people in the United States develop cancer
• What is the most common cause of cancer?
¥ Environmental chemicals and cigarette smoke cause most cancers (70 – 80%)
• What are the 2 major types of fluid connective tissue?
o What functions are associated with each type?
Fluid Connective Tissues are blood and lymph
¥ Watery matrix of dissolved proteins
¥ Carry specific cell types (formed elements)
¥ Formed elements of blood
¥ Red blood cells (erythrocytes)
¥ White blood cells (leukocytes)
¥ Platelets
Lymph forms as interstitial fluid is filtered into lymphatic vessels
¥ Transported through vessels of the lymphatic system
¥ Monitored by immune system
¥ “Cleaned” fluid is returned to bloodstream
