Chapter 4 Review (7 questions) 1 short

Question 1

• What are tissues composed of?

Answer 1

Tissues are collections of cells and cell products that perform specific, limited functions
Four types of tissue

Question 2

• What are the 4 types of tissue?

Answer 2

1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Neural tissue

Question 3

o What are the main functions of each type of tissue?

Answer 3

1. Provide physical protection cover exposed surfaces
2. Control permeability all substances that enter/leave the body cross an epithelium
3. Provide sensation specialized epithelia facilitate smell, taste, sight, equilibrium, hearing
4. Produce specialized secretions (glandular epithelium) sweat, mucus, oil, milk, hormones

Question 4

• What are the 5 major characteristics of epithelia?

Answer 4

1. Cellularity cell junctions
2. Polarity apical and basal surfaces
3. Attachment basement membrane or basal lamina
4. Avascularity lack blood vessels
5. Regeneration stem cells divide to replace lost cells

Question 5

• How is epithelial integrity maintained?

Answer 5

1. Intercellular connections
   ¥ Transmembrane proteins called CAMs (cell adhesion molecules) can connect adjacent membranes at cell junctions
2. Attachment to the basement membrane
   ¥ Hemidesmosome connects cytoskeleton of cell to the basement membrane
3. Epithelial maintenance and repair
   ¥ Cells are replaced by division of germinative cells (stem cells) near the basement membrane

Question 6

• Describe the structure and function of tight & gap junctions, desmosomes, and hemidesmososmes.

Answer 6

1. Tight junction seals plasma membranes between cells, prevents passage of water and solutes
2. Gap junction connects cytoplasm of adjacent cells, allows rapid communication
3. Desmosome connects cytoskeleton of adjacent cells, allows bending and twisting
   ¥ Hemidesmosome connects cytoskeleton of cell to the basement membrane

Question 7

• How are epithelia classified?

Answer 7

1. Based on cell shape
   ¥ Squamous epithelia thin and flat
   ¥ Cuboidal epithelia square shaped
   ¥ Columnar epithelia tall, slender rectangles
2. Based on number of cell layers
   ¥ Simple epithelium single layer of cells
   ¥ Stratified epithelium several layers of cells

Question 8

o What functions are associated with each class of epithelia?

Answer 8

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

Question 9

• How are endocrine and exocrine glands similar? How are they different?

Answer 9

Endocrine glands
¥ Release hormones into interstitial fluid
¥ No ducts
Exocrine glands
¥ Release secretions onto epithelial surfaces

Question 10

• What are the 3 modes of secretion?

o How is the product secreted in each case?

Answer 10

1. Merocrine secretion product released in vesicles (exocytosis) most common, ex: sweat glands
2. Apocrine secretion product released by shedding cytoplasm, ex: mammary glands
3. Holocrine secretion product released by cell bursting (killing gland cells), ex: sebaceous glands

Question 11

• How are glands categorized?

Answer 11

¥ 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

Question 12

• What are the 3 major classes of connective tissue?

Answer 12

1. Connective tissue proper loose and dense CT
   ¥ Connect and protect
2. Fluid connective tissues blood and lymph
   ¥ Transport, defense
3. Supporting connective tissues cartilage and bone
   ¥ Structure and strength

Question 13

• How does the composition of the matrix influence the functions of each type of connective tissue?

Answer 13

¥ 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

Question 14

• What is the main difference between loose and dense connective tissues?

Answer 14

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

Question 15

• What cells are commonly found in connective tissue proper?
o What are their functions?

Answer 15

¥ 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

Question 16

• What are the 3 types of fibrous proteins commonly found in connective tissue?

Answer 16

¥ 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

Question 17

• What types of connective tissue are present in embryos?

Answer 17

¥ 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

Question 18

• What are the 3 types of loose connective tissue that are present in adults?
o What functions are associated with each type?

Answer 18

1. Areolar least specialized, open structure with elastic fibers, highly vascularized
   ¥ ex: under skin
2. Adipose primarily contains adipocytes, padding, shock absorption, insulation
   ¥ ex: surrounds kidneys
3. Reticular complex network of fibers support functional cells (parenchyma)
   ¥ ex: liver

Question 19

• What are the 3 types of dense connective tissue?

o What functions are associated with each type?

Answer 19

1. 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
2. Dense irregular connective tissue no consistent pattern of fibers, absorb stresses from many directions
   ¥ Ex: layer under skin, organ capsules

Question 20

• What are the 2 major types of supportive connective tissue?
o What functions are associated with each type?

Answer 20

Cartilage 
¥	Gel-type ground substance
¥	For shock absorption and protection
Bone 
¥	Calcified (made rigid by calcium salts   and other minerals)
¥	For weight support

Question 21

• What is the structure of cartilage?

Answer 21

¥ No blood vessels (avascular) materials must diffuse through matrix
¥ Surrounded by perichondrium
¥ Outer, fibrous layer (for strength)
Inner, cellular layer (for growth and maintenance

Question 22

• How can cartilage grow? (explain both mechanisms)

Answer 22

¥ 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)

Question 23

• What are the 3 types of cartilage?

o What functions are associated with each type?

Answer 23

1. Hyaline cartilage stiff, flexible support, reduces friction between bones, most common
   ¥ Found in joints, rib tips, sternum, and trachea
2. Elastic cartilage supportive but bends easily
   ¥ Found in external ear and epiglottis
3. Fibrocartilage prevents bone-to-bone contact, resists compression, absorbs shock
   ¥ Pads knee joints, found between pubic bones and intervertebral discs

Question 24

• What is the structure and function of bone?

What are membranes composed of?

Answer 24

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

Question 25

• What are the 4 types of membranes?

Answer 25

1. Mucous membranes
2. Serous membranes
3. Cutaneous membrane
4. Synovial membranes

Question 26

o What is the relationship between the structure of each type of membrane and its function?

Answer 26

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

Question 27

• What are the 3 types of fasciae?

o What is the function of each fascia?

Answer 27

1. Superficial fascia layer of areolar and adipose tissue, separates skin from underlying tissues
2. Deep fascia dense irregular CT, connects to capsules surrounding organs, perichondrium, periosteum, muscle tendons
3. Subserous fascia areolar layer between deep fascia and serous membranes

Question 28

• What are the 3 types of muscle tissue?

o What is the structure and function of each type?

Answer 28

1. Skeletal muscle tissue
   ¥ Large body muscles responsible for movement
2. Cardiac muscle tissue
   ¥ Found only in the heart
3. Smooth muscle tissue
   ¥ Found in walls of hollow organs (blood vessels; urinary bladder; respiratory, digestive, and reproductive tracts)

Question 29

o What are the characteristics of the cells of each type of muscle tissue?

Answer 29

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

Question 30

• How is the organization of neural tissue in the body different from the other types of tissue?

Answer 30

¥ 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

Question 31

• What 2 types of cells are classified as neural tissue?

o What is the function of each cell type?

Answer 31

1. Neurons (nerve cells)
   ¥ Perform electrical communication
2. Neuroglia supporting cells
   ¥ Repair and supply nutrients to neurons

Question 32

o How is the structure of a neuron specialized for communication?

Answer 32

¥ 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

Question 33

• How do tissues respond to injuries?

Answer 33

¥ Cells restore homeostasis with two processes

1. Inflammation
2. Regeneration

Question 34

o Which tissues can regenerate well?

Answer 34

¥ Epithelia and connective tissues regenerate well

Question 35

• How do our tissues change as we age?

Answer 35

¥ Thinning epithelia and connective tissues
¥ Increased bruising and bone brittleness
¥ Joint pain and broken bones
¥ Cardiovascular disease
¥ Mental deterioration

Question 36

• What is the relationship between age and cancer incidence?

Answer 36

¥ Cancer rates increase with age

¥ 25% of all people in the United States develop cancer

Question 37

• What is the most common cause of cancer?

Answer 37

¥ Environmental chemicals and cigarette smoke cause most cancers (70 – 80%)

Question 38

• What are the 2 major types of fluid connective tissue?

o What functions are associated with each type?

Answer 38

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