CH 4 Tissues

Question 1

Define tissues

Answer 1

A group of similar cells and their intracellular substance specialized to perform a specific function; primary tissue types of the body are epithelial, connective, muscle and nervous tissue

Question 2

Define histology

Answer 2

Branch of anatomy dealing with the microscopic structure of tissues

Question 3

What are the four types of tissues?

Answer 3

Epithelial
Connective
Muscle
Nervous

Question 4

Know and explain the basic characteristics of epithelial tissue. What are the 5 distinguishing features?

Answer 4

1. polarity–top and bottom side of tissue (apical: free side, exposed to surface or cavity. Basal surface: attached side; attaches to the basal lamina)
2. specialized contacts–contact points: epithelial tissues need to fir closely together (tight junctions and desmosomes)
3. Connective tissue support – epithelial tissue is supported by connective tissue. Connective tissue always lies below epithelial tissue. Reticular lamina and basement membrane.
4. Avascular, but innervated–no blood vessels. Does contain nerve fibers
5. Regenerative–highly mitotic

Question 5

Define apical surface

Answer 5

free side, exposed to surface or cavity

Question 6

Define basal surface

Answer 6

attached side; attaches to basal lamina

Question 7

Define basal lamina

Answer 7

noncellular, adhesive supporting sheet consisting largely of glycoproteins secreted by epithelial cells.

Question 8

Define reticular lamina

Answer 8

A layer of extracellular material containing a fine network of collagen fibers; together with the basal lamina it is a major component of the basement membrane.

Question 9

Define basement membrane

Answer 9

Extracellular material consisting of a basal lamina secreted by epithelial cells and a reticular lamina secreted by underlying connective tissue cells

Question 10

Define asvascular

Answer 10

lack of blood supply

Question 11

How are epithelial tissue classified. Name these classification categories

Answer 11

by 1. number of layers (one layer–simple; more than one–stratified)
2. shape of cells (flat cells–squamous; cube like–cuboidal; like a column–columnar)

Question 12

What are the epithelial tissue types?

Answer 12

1. simple squamous epithelium
2. simple cuboidal epithelium
3. simple columnar epithelium
4. Pseudostratified columnar epithelium
5. stratified squamous epithelium
6. stratified cubodial epithelium
7. stratified columnar epithelium
8. transitional epithelium

Question 13

Describe Simple Squamous epithelium

Answer 13

single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm, the simplest of the epithelial cells.
Function: allows material to pass by diffusion
In areas where lots of diffusion is needed (air sacs of lung)

Question 14

Describe simple cuboidal epithelium

Answer 14

Description: single layer of cubelike cells with large, spherical central nuclei
Function: secretion and absorption
Location: kidney tubules, ducts and secretory portions of small glands, ovary surface

Question 15

Describe simple columnar epithelium

Answer 15

Description: single layer of tall cells with round to oval nuclei; main cells bear microvilli, some bear cilia; layer may contain mucus secreting unicellular glands (goblet cells)
Functions: Absorption; secretion of mucus, enzymes and other substances; ciliated types propels mucus (or reproductive cells) by ciliary action
Location: digestive tract

Question 16

Describe pseudostratified columnar epithelium

Answer 16

Description: single layer of cells of differing heights, some not reaching the free surface
Function: secrete substances particularly mucus; propulsion of mucus by ciliary action
Location: trachea

Question 17

Describe stratified squamous epithelium

Answer 17

Description: thick membrane composed of several cell layers
Function: protects underlying tissues on areas subjected to abrasion
Location: esophagus, mouth and vagina

Question 18

Describe Stratified cuboidal epithelium

Answer 18

quite rare. found in some sweat and mammary glands
Typically 2 cells layers thick

Question 19

Describe stratified columnar epithelium

Answer 19

very limited in the body. small amounts found in the pharynx, male urethra, and lining of granular ducts
Only the apical layer is columnar

Question 20

Describe transitional epithelium

Answer 20

Description: resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch
Function: stretches readily, permits stored urine to distend urinary organ
Location: Lines the ureters, bladder and part of the urethra

Question 21

What is glandular epithelium?

Answer 21

Secretes substances onto the surface or space.
Glands classified by:
-site of production
-number of cells forming the gland
Site of product release:
-Endocrine
-Exocrine

Question 22

What are the characteristics of connective tissue?

Answer 22

Most abundant and widely distributed of primary tissues
provides binding and support, protecting, insulation, storing reserve fuel and transporting substances (blood)

Question 23

list and describe the four main classes of connective tissue

Answer 23

1. Connective tissue proper
   -2 categories: loose and dense
2. cartilage
   -tough, flexible; lack nerve fibers
3. bone
   -supports and protects; stores fat and synthesizes blood cells, more collagen than cartilage, inorganic calcium salts.
4. blood

Question 24

What is the extracellular matrix? describe what it is composed of

Answer 24

ground substance: gel-like (can be solid or liquid) material between cells
Composed of:
-collagen
-elastic fibers
-reticular

Question 25

Describe the three types of connective tissue fibers

Answer 25

Collagen: made of protein, collagen. Strongest and most abundant type. Tough; provides high tensile strength Elastic Fibers: long thin elastin (protein) fibers; stretch and recoil Reticular fibers: short, fine, highly branched collagenous fibers (different chemistry and form from collagen fibers). Branching forms networks that offer more give.

Question 26

What are the main types of cells found in connective tissue?

Answer 26

"blast" cells (immature version of the cell and is making something) -fibroblast: makes the fibers of connective tissue (the 3 above) -chondroblasts: cells that make cartilage matrix -osteoblasts: cells that make bone tissue -hematopoietic stem cell: make blood cells "Cytes" cells are the mature forms of "blasts" cells -fibrocytes -chondrocytes -osteocytes Other cells -adipocytes (fat cells) -white blood cells -mast cells (inflammatory response) -macrophages

Question 27

Name and describe the types of connective tissue proper

Answer 27

2 categories: loose and dense -Areolar (loose connective)--part of dermis is made up of this -Adipose (loose connective)--fat -Reticular (loose connective)--in organs a lot -Dense regular (dense connective)--tendons and ligaments -dense irregular (dense connective)--joint capsule -Elastic connective (dense connective)-- walls of arteries

Question 28

What are the three types of cartilage? describe each

Answer 28

1. Hyaline--amorphous but firm matrix, collagen fibers from an imperceptible network; chondroblasts produce the matrix when mature (chondrocytes) like in lacunae. Function: supports and reinforces; serves as a resilient cushion; resists compressive stress. Location: from most of the embryonic skeleton, covers the end of the long bone in joint cavities; forms costal cartilage of ribs; cartilage in the nose, trachea, and larynx. 2. elastic--similar to hyaline cartilage, but with more elastic fibers in the matrix. Functions include maintaining the shape and structure while allowing great flexibility. Location: supports the external ear (pinna); epiglottis. 3. fibrocartilage--matric similar to but less firm than that in hyaline cartilage; thick collagen fibers predominate. Functions: tensile strength allows it to absorb compressive shock. Location: intervertebral disc; pubic symphysis; disc of the knee joint.

Question 29

Define chondroblasts

Answer 29

Actively miotic cell of cartilage

Question 30

Define Chondrocyte

Answer 30

Mature cell of cartilage

Question 31

Define Lacunae

Answer 31

A small space, cavity, or depression; lacunae in bone or cartilage are occupied by cells.

Question 32

What is bone?

Answer 32

A connective tissue that forms the bony skeleton

Question 33

Define osteoblast

Answer 33

Bone forming cell

Question 34

define osteocytes

Answer 34

mature bone cells

Question 35

define osteons

Answer 35

individual structural units

Question 36

Blood is classified as what type of tissue? explain

Answer 36

connective. This is because it develops from mesenchyme and consists of blood cells surrounded by a nonliving fluid matrix called blood plasma

Question 37

What are the basic characteristic of muscle tissue?

Answer 37

Muscle tissue is highly vascularized, responsible for most types of movement, and made up of myofilaments (actin and myosin).

Question 38

What are the three types of muscle tissue?

Answer 38

1. skeletal muscle--long cylindrical, multinucleate cells; obvious striations. Functions include voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control. Located: skeletal muscles attached to bones or occasionally to the skin 2. Cardiac muscle--branching, striated, generally uninucleate cells that intercalated at specialized junctions (intercalated disc). Function: as it contracts, it propels blood into the circulation; involuntary control. Location: walls of the heart 3. smooth muscle--spindle-shaped (elongated) cells with central nuclei; no striations; cells arranged closely to form sheets. Functions: propels substances or objects along internal passageways; involuntary control. Located in walls of hollow organs

Question 39

What are the characteristics of nervous tissue?

Answer 39

The main components of the nervous system are the brain, spinal cord, and nerves. Regulates and controls body functions.

Question 40

Name the cells found in nervous tissue

Answer 40

1. Neurons--nerve cells: generate and conduct nerve impulses. branching cells, cell processesthat may be quite long extended from the nucleus-containing cell body; also contributing to nervous tissue are nonexctiable support cells. Function: neurons transmit electrical signals from sensory receptors and to effect (muscle and glands). located in the brain, spinal cord, and nerves. 2. supporting cells (neuroglial cells or glial cells)-- support, insulate, and protect neurons.

Question 41

Name and describe the three membranes covering and lining the body

Answer 41

all membranes are composed of epithelium bound to the underlying connective tissue proper layer. 1. cuntaneous membranes--another name for the skin. keratinized stratified squamous epithelium (epidermis) attached to a thick layer of connective tissue (dermis). Dry membrane 2. mucous membranes--also called mucosae. line body cavitities that are open to the exterior (ex: digestive, respiratory, and urogenital tracts). moist membranes bathed by secretions. may secrete mucus. 3. serous membranes--also called serosae. found in closed ventral body cavities. simple squamous epithelium (called mesothelium) resting on thin areolar connective tissue. -parietal serosae: internal body cavity walls -visceral serosae: cover internal organs -cavity between layers: filled with serous fluid

Question 42

define regeneration

Answer 42

replaces destroyed tissue with the same kind of tissue

Question 43

define fibrosis

Answer 43

replaces damaged tissue with scar tissue, which is dense connective tissue.

Question 44

What types of tissue regenerate extremely well?

Answer 44

-epithelial tissue -bone -areolar connective tissue -dense irregular connective tissue -blood-forming tissue

Question 45

What types of tissue have moderate regenerating capacity?

Answer 45

smooth muscle and dense regular connective tissue

Question 46

What tissues have no regenerative capacity?

Answer 46

cardiac muscle, nervous tissue of brain and spinal cord.