Tissue Types

Question 1

What are the four basic tissues of the body?

Answer 1

Epithelial, Connective Tissue, Muscle, Nerve

Question 2

What does epithelial tissue do? (4)

Answer 2

Forms barriers between inside and outside world and between compartments of the body, covers exposed body surfaces, lines hollow organs/ body cavities/ ducts of glands, and forms glands

Question 3

What does connective tissue do? (4)

Answer 3

Links tissues and organs together, stores energy, forms immune system, provides structural and metabolic support

Question 4

What does muscle tissue do? (3)

Answer 4

Specialized for contraction, generates force to produce motion of body parts and move substances through blood vessels and hollow organs, and maintains body temp

Question 5

What does nervous tissue do? (2)

Answer 5

Receives/processes/integrates signals from within the body and from external environment, generates and transmits impulses that control and integrate various functions

Question 6

What are the characteristics of epithelia? (5)

Answer 6

Avascular, continuous, rest on basal lamina, little ECM, polarized (apical and basolateral surfaces differ)

Question 7

How are epithelia named? (2 factors)

Answer 7

According to number of layers of cells (1 is simple, and more than 1 is striated)
According to shape of cells in the outermost layer (squamous is flat, columnar, cuboidal)

Question 8

What is simple squamous epithelium?

Answer 8

Single layer of flat cells (apical-basal distance short)
Lines body cavities (mesothelium)
Lines heart chambers and blood vessels (endothelium)
Lines sites of gas exchange in lungs

Question 9

What is simple cuboidal epithelium?

Answer 9

Single layer of cells with height equaling width (cuboidal)
Found in areas where secretion or absorption occurs (have room for machinery)
Found in glands and their ducts
Line portions of kidney tubule system

Question 10

What is simple columnar epithelium?

Answer 10

Single layer of cells, they are taller than they are wide (provide protection)
Line digestive tract, fallopian tubes and excretory ducts such as those from gall bladder

Question 11

What is stratified squamous epithelium?

Answer 11

Stratified cells, outermost layer is squamous
Found where mechanical stresses are severe
Forms outer layer of skin, lines rectum/ anus/ mouth/ esophagus and vagina
Keratin- dehydration

Question 12

What is stratified cuboidal epithelium?

Answer 12

Two to three layers of cells, outermost layer has cells of equal height and width
Relatively rare, line ducts of larger exocrine glands
Found in ducts of mammary and sweat glands

Question 13

What is stratified columnar epithelium?

Answer 13

Multiple layers of cells, outermost layer has cells with greater height than width
Relatively rare- found in large excretory ducts and portions of pharynx, urethra and anus

Question 14

What is pseudostratified columnar epithelium?

Answer 14

Nuclei appear at multiple levels, all cells touch basal lamina but not many touch luminal surface
Found in respiratory system and male reproductive tract

Question 15

What is transitional epithelium?

Answer 15

Multiple layers of cells, outermost cells are large and dome shaped
Found only in urinary tract (for expansion and retraction of bladder)

Question 16

What are glands?

Answer 16

Composed of epithelial cells and form by growth of epithelial cells into underlying connective tissue
Exocrine glands release secretions through ducts onto epithelial surfaces
Endocrine glands lack ducts and secrete hormones into the blood

Question 17

What happens in the formation of glands?

Answer 17

Epithelial cells grow into underlying connective tissue
Exocrine: secretory cells remain connected to surface by a duct
Endocrine: connecting cells disappear, secretions released into blood vessels

Question 18

What are the three mechanisms of secretion?

Answer 18

Merocrine: normal exocytosis (vesicles fuse to apical surface and release secretory contents)
Apocrine: apical surface pinched off
Holocrine: entire cell released, cell IS secretory products

Question 19

What are the three classifications (and 6 subclasses) of connective tissue?

Answer 19

Connective tissue proper (loose and dense)
Fluid connective tissue (blood and lymph)
Supporting connective tissue (cartilage and bone)

Question 20

What are the characteristics of connective tissue?

Answer 20

Relatively few cells and abundance of ECM

Question 21

What is in the connective tissue matrix?

Answer 21

Ground substance: highly hydrated gel
Fibres: collagen (form bundles that provide tensile strength), reticular (form branching network that supports cells), elastic (thin branching fibres that function like rubber bands)

Question 22

What do fibroblasts and macrophages do in the connective tissue structure?

Answer 22

Fibroblasts secrete ground substance and fibres
Macrophages ingest debris and function in immune response

Question 23

What is the classification of connective tissue based on?

Answer 23

Density of fibers, types of fibers, preponderance of specific cell type

Question 24

What is mesenchyme?

Answer 24

Connective tissue, found in developing embryo, remains as stem cells in adult tissue

Question 25

What is loose connective tissue?

Answer 25

Packing material- fills spaces between organs, provide cushioning and support Abundance of ground substance or cells Relatively few fibers 3 types: areolar, adipose, reticular

Question 26

What is areolar connective tissue?

Answer 26

Most common and least specialized connective tissue Links together other tissues and organs throughout body Open framework- ground substance and elastic fibers

Question 27

What is adipose connective tissue

Answer 27

Fat tissue Forms deposits in specific areas of the body (determined largely by genetics) Functions in padding, insulation and energy storage

Question 28

What is dense connective tissue?

Answer 28

Abundance of fibers, relatively little ground substance and few cells

Question 29

What is dense irregular connective tissue?

Answer 29

Fibers unaligned and run at variety of different angles Forms dermis of skin, organ capsules, sheaths around bones and muscles and nerves

Question 30

What is dense regular connective tissue?

Answer 30

Fibers aligned in one direction Forms tendons (muscles to bones) and ligaments (bone to bone)

Question 31

What are membranes?

Answer 31

Composed of epithelium and connective tissue Lines surfaces, cavities, and hollow organs

Question 32

What are fluid connective tissues?

Answer 32

Blood- composed of cells and plasma, plasma forms fluid matrix Lymph- composed of lymphocytes and lymph fluid, lymph fluid is a dilute solution of proteins and excess interstitial fluid

Question 33

What are supporting connective tissues?

Answer 33

Consists of cartilage and bone Extensive incompressible matrix Support soft tissues of the body

Question 34

What are characteristics of muscle tissue?

Answer 34

Elongated cells, specialized to contract and generate force

Question 35

What are the three types of muscle tissue?

Answer 35

Skeletal- attaches to bones, striated (pattern of bands), voluntary contraction Smooth- associated with viscera, non-striated, involuntary contraction Cardiac- only in heart, striated, involuntary contraction

Question 36

What is skeletal muscle?

Answer 36

Forms long cylindrical multinucleated tubes Exhibits distinct cross banding patterns Stabilizes and moves the articulated skeleton

Question 37

What is smooth muscle?

Answer 37

Cells short, spindle shaped, contain single nucleus, not striated, forms walls of blood vessels and hollow organs, specialized for slow sustained contractions

Question 38

What is cardiac muscle?

Answer 38

Cells short, branched, striated and contain single nuclei Specialized for continuous rhythmic contraction in one direction (apical to tubes)

Question 39

What are the characteristics of nervous tissue?

Answer 39

Highly asymmetrical cells with long cytoplasmic processes Transmit electrical signals via ionic conductions Axon, dendrites, cell body, etc