The tissue level of organization- Connective tissue

Question 1

What are the components of connective tissue

Answer 1

1. Specialized cells
2. Extracellular protein fibers
3. Fluid called ground substance

Question 2

What are the functions of connective tissues?

Answer 2

– 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 triglycerides
– Defending the body from invading microorganisms

Question 3

State the categories of connective tissues

Answer 3

1. Connective tissue proper
   * Connect and protect
2. Fluid connective tissues
   * Transport
3. Supporting connective tissues
   * Structural strength

Question 4

State the categories of connective tissue proper

Answer 4

– Loose connective tissue
* More ground substance, fewer fibers
* Example: fat (adipose tissue)
– Dense connective tissue
* More fibers, less ground substance
* Example: tendons

Question 5

What are the cells of connective tissue proper

Answer 5

– Fibroblasts
– Fibrocytes
– Adipocytes
– Mesenchymal cells
– Melanocytes
– Macrophages
– Mast cells
– Lymphocytes
– Microphages

Question 6

Describe Fibroblasts

Answer 6

– The most abundant cell type
– Found in all types of connective tissue proper
– Secrete proteins and hyaluronan (cellular ceme

Question 7

Describe Fibrocytes

Answer 7

– Second most abundant cell type
– Maintain connective tissue fibers

Question 8

Describe Adipocytes

Answer 8

– Fat cells
– Each cell stores a single, large fat droplet

Question 9

Describe Mesenchymal cells

Answer 9

– Stem cells that respond to injury or infection
– Differentiate into fibroblasts, macrophages, etc.

Question 10

Describe Melanocytes

Answer 10

– Synthesize and store the brown pigment melanin

Question 11

Describe Macrophages

Answer 11

– Large phagocytic cells of the immune system
– Engulf pathogens and damaged cells
– Fixed macrophages stay in tissue
– Free macrophages migrate

Question 12

Describe Mast Cells

Answer 12

– Stimulate inflammation after injury or infection
* Release histamine and heparin
– Basophils are leukocytes that also contain histamine and heparin

Question 13

Describe lymphocytes

Answer 13

– Migrate throughout the body
– May develop into plasma cells, which produce
antibodies

Question 14

Describe Microphages

Answer 14

– Phagocytic blood cells (neutrophils, eosinophils)
– Attracted to signals from macrophages and mast cells

Question 15

State the three types of connective tissue fibers

Answer 15

1. Collagen fibers
2. Reticular fibers
3. Elastic fibers

Question 16

Describe Reticular fiber

Answer 16

– Form a network of interwoven fibers (stroma)
– Strong and flexible
– Resist forces in many directions
– Stabilize functional cells (parenchyma) and structures
– Example: sheaths around organs

Question 17

Describe Elastin Fibers

Answer 17

– Contain elastin
– Branched and wavy
– Return to original length after stretching
– Example: elastic ligaments of vertebrae

Question 18

What is Ground substance

Answer 18

– Is clear, colorless, and viscous
– Fills spaces between cells and slows pathogen
movement

Question 19

Describe Loose connective tissues

Answer 19

– “Packing materials”
– Fill spaces between organs, cushion cells, and support
epithelia

Question 20

Describe embryonic connective tissues

Answer 20

– Not found in adults
– Mesenchyme (embryonic connective tissue)
* First connective tissue in embryos
– Mucous connective tissue
* Loose embryonic connective tissue

Question 21

What are the types of loose connective tissues in adults

Answer 21

1. Areolar tissue
2. Adipose tissue
3. Reticular tissue

Question 22

Describe the Areolar Tissue

Answer 22

– Least specialized
– Open framework
– Viscous ground substance
– Elastic fibers
– Holds capillary beds
* Example: under skin (subcutaneous layer)

Question 23

Describe Adipose Tissue

Answer 23

– Contains many adipocytes (fat cells)
* Adipocytes in adults do not divide
– Expand to store fat
– Shrink as fats are released
* Mesenchymal cells divide and differentiate
– To produce more fat cells
– When more storage is needed
– May be removed (temporarily) via liposuction in cosmetic surgery

Question 24

What is white fat?

Answer 24

– Most common
– Stores fat and absorbs shocks
– Slows heat loss (insulation)

Question 25

What is Brown Fat

Answer 25

– Found in babies and young children – More vascularized – Adipocytes have many mitochondria – Breakdown of lipids releases energy and warms body

Question 26

Describe the reticular tissue

Answer 26

Provides support – Reticular fibers form a complex, three-dimensional stroma – Support functional cells of organs – Found in liver, kidney, spleen, lymph nodes, and bone marrow

Question 27

What is another name for dense connective tissue

Answer 27

Collagenous tissues

Question 28

What are the three types of dense connective tissue

Answer 28

Dense regular * Dense irregular * Elastic

Question 29

Describe Dense regular connective tissue

Answer 29

– Tightly packed, parallel collagen fibers * Tendons attach muscles to bones * Ligaments connect one bone to another and stabilize organs * Aponeuroses are tendinous sheets that attach a broad, flat muscle to another structure

Question 30

Describe Dense irregular connective tissue

Answer 30

– Interwoven network of collagen fibers * Provides strength to dermis * Forms sheath around cartilages (perichondrium) and bones (periosteum) * Forms capsules around some organs (e.g., liver, kidneys, and spleen)

Question 31

What are three layers of fasciae

Answer 31

1. Superficial fascia * Separates skin from underlying tissues 2. Deep fascia * Sheets of dense regular connective tissue 3. Subserous fascia * Lies between deep fascia and serous membranes that line body cavities

Question 32

Fluid connective tissue include:

Answer 32

blood and lymph

Question 33

Describe the blood

Answer 33

Contains a watery matrix called plasma – Contains cells and cell fragments, collectively known as formed elements * Red blood cells (erythrocytes) * White blood cells (leukocytes) * Platelets

Question 34

Describe lymph

Answer 34

– Forms as interstitial fluid that enters lymphatic vessels – Monitored by immune system – Returned to veins near the heart

Question 35

Supporting connective tissue include

Answer 35

cartilage and bone

Question 36

What are the types of cartilage and describe

Answer 36

▪ Hyaline cartilage – Most common type – Tough and somewhat flexible – Reduces friction between bones – Found in synovial joints, rib tips, sternum, and trachea ▪ Elastic cartilage – Supportive but bends easily – Found in external ear and epiglottis Fibrocartilage – Very durable and tough – Limits movement – Prevents bone-to-bone contact – Found around joints, between pubic bones, and between spinal vertebrae

Question 37

The types of cartilage growth are

Answer 37

– Interstitial growth * Enlarges cartilage from within – Appositional growth * Growth at outer surface of cartilage

Question 38

Describe the bone

Answer 38

For weight support – Calcified (made rigid by calcium salts) – Resists shattering (flexible collagen fibers) – Osteocytes (bone cells) lie in lacunae * Arranged around central canals within matrix * Small channels through matrix (canaliculi) allow for exchange of materials with blood – Periosteum covers bone * Fibrous (outer) and cellular (inner) layers

Question 39

What is the function of tissue membrane

Answer 39

– Physical barriers – Line or cover body surfaces – Consist of an epithelium supported by connective tissue

Question 40

What are the four types of tissue membranes

Answer 40

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

Question 41

Describe the mucous membranes?

Answer 41

– Line passageways that have external connections – In digestive, respiratory, urinary, and reproductive tracts – Epithelial surfaces must be moist * To reduce friction * To facilitate absorption or secretion – Lamina propria is areolar tissue in mucous membranes

Question 42

Describe the Serous membranes

Answer 42

– Line cavities that do not open to the outside – Thin but strong – Parietal portion lines inner surface of cavity – Visceral portion (serosa) covers the organs – Serous fluid reduces friction

Question 43

What are the different types of serous membranes and describe

Answer 43

1. Peritoneum * Lines peritoneal cavity * Covers abdominal organs 2. Pleura * Lines pleural cavities * Covers lungs 3. Pericardium * Lines pericardial cavity * Covers heart

Question 44

Describe the cutaneous membrane

Answer 44

– Skin that covers the body – Thick, relatively waterproof, and usually dry

Question 45

Describe the synovial membranes

Answer 45

– Line synovial joint cavities – Movement stimulates production of synovial fluid for lubrication – Lack a true epithelium