Lecture 16 9/19/23

Question 1

What is connective tissue?

Answer 1

tissue whose main function is to provide structure and support for other tissues

Question 2

What are the different types of connective tissue (for our class)?

Answer 2

-connective tissue proper
-elastic connective tissue
-reticular connective tissue
-adipose tissues
-embryonic connective tissues

Question 3

What are the characteristics of connective tissue proper?

Answer 3

-basic connective tissue
-holds other tissues together
-main cells are fibroblasts
-extracellular matrix contains collagen and ground substance

Question 4

What are the characteristics of fibroblasts?

Answer 4

-spindle-shaped
-produce the extracellular matrix
-important in tissue repair

Question 5

What happens with fibroblasts in tissue repair?

Answer 5

-they transform into myofibroblasts
-have contractile ability
-secrete more extracellular matrix; brings wound together

Question 6

What are the characteristics of collagen?

Answer 6

-long, strong protein fibers
-provide tensile strength
-different arrangements of a-chains lead to different collagen types

Question 7

What are the two main types of collagen (for our class)?

Answer 7

-type 1; main structural collagen
-type 3; reticulin

Question 8

What are the characteristics of type 1/main structural collagen?

Answer 8

-forms ligaments, tendons, dermis, and bone
-shows up as pink fibers on histology

Question 9

What is the main characteristic of type 3/reticulin?

Answer 9

forms lacy structure of parenchymal organs

Question 10

What are the characteristics of ground substance?

Answer 10

-complex carbohydrate and protein meshwork
-attracts water to form a gel
-provides compression resistance
-lubricates and hydrates
-provides nutrient and waste transport

Question 11

What are glycosaminoglycans?

Answer 11

-long, unbranched polysaccharide chains
-complex with proteins to form bottlebrush-shaped proteoglycans in ground substance

Question 12

What is hyaluronic acid?

Answer 12

a large glycosaminoglycan that will bind multiple proteoglycans to provide additional structure

Question 13

What are the two structural glycoproteins?

Answer 13

-integrins
-fibronectin

Question 14

What is the role of integrins?

Answer 14

to be embedded in the cell membrane and attach to various molecules, including fibronectin

Question 15

What is the role of fibronectin?

Answer 15

bind integrins to collagen

Question 16

What is the location/purpose of loose connective tissue?

Answer 16

-surrounds vessels/nerves, underlies epithelia, and forms mesentery
-loosely holds tissue together

Question 17

How can loose connective tissue be identified?

Answer 17

-lots of ground substance
-fewer, irregularly arranged collagen fibers
-sparse fibroblasts

Question 18

What is the location/purpose of dense irregular connective tissue?

Answer 18

-forms dermis of skin, submucosa of intestines, and organ capsules
-resists forces/stretch in different directions

Question 19

How can dense irregular connective tissue be identified?

Answer 19

-lots of collagen fibers with many intersecting bundles
-less ground substance
-few fibroblasts

Question 20

What is the location/purpose of dense regular connective tissue?

Answer 20

-forms tendons, ligaments, and aponeuroses
-resists forces in one direction

Question 21

How can dense regular connective tissue be identified?

Answer 21

-lots of parallel collagen fibers
-less ground substance
-few fibroblasts

Question 22

What are the characteristics of elastic connective tissue?

Answer 22

-high proportion of elastin
-cross-linked structure allowing for stretch and coil

Question 23

What is the location of elastic connective tissue?

Answer 23

-arteries
-nuchal ligament
-vocal cords

Question 24

How can elastic connective tissue be identified?

Answer 24

-knowing its location
-looking for wavy, dark pink lines in arteries when special stain is used

Question 25

What are the location and function of reticular connective tissue?

Answer 25

-forms fine network of reticulin fibers to support parenchymal organs

Question 26

How can reticular connective tissue be identified?

Answer 26

-need reticulin stain -fibers will stain black; nothing else will dye

Question 27

What are the functions of white adipose tissue?

Answer 27

-energy storage -impact protection -insulation

Question 28

Where can white adipose be found?

Answer 28

almost everywhere in the body

Question 29

How can white adipose tissue be identified?

Answer 29

-cells are signet-ring shaped -one large clear lipid droplet -single large, peripheral nucleus -occur in clusters/sheets

Question 30

What are the characteristics of brown adipose tissue?

Answer 30

-found in neonates, rodents, and hibernating animals -actively generates heat/involved in thermoregulation -stays separate from white fat

Question 31

How can brown adipose tissue be identified?

Answer 31

-many small lipid droplets -occur in sheets

Question 32

What is mesenchyme?

Answer 32

primitive tissue in embryos

Question 33

Where can mucous connective tissue be seen?

Answer 33

-in juveniles, around the vessels of the umbilicus -in adult chickens in the wattles/combs

Question 34

What are the two types of embryonic connective tissue?

Answer 34

-mesenchyme -mucous connective tissue

Question 35

What is muscle tissue?

Answer 35

tissue that specializes in contration/movement

Question 36

What are the three types of muscle tissue?

Answer 36

-skeletal -cardiac -smooth

Question 37

What is the function of skeletal muscle?

Answer 37

-primarily voluntary movement -limited involuntary/semi-voluntary movement

Question 38

How is skeletal muscle organized?

Answer 38

-each myofiber muscle cell unit has hundred of myofibrils and is multinucleated -myofiber muscle cell units form fascicles -each muscle muscle contains many fascicles

Question 39

What are the characteristics of an individual myofibril?

Answer 39

-composed of repeating sarcomeres -each sarcomere has parallel arrays of actin and myosin -actin and myosin form visible cross striations

Question 40

How does skeletal muscle appear in longitudinal sections?

Answer 40

-long, parallel fibers -peripheral nuclei -cross striations

Question 41

How does skeletal muscle appear in transverse sections?

Answer 41

-round/polygonal fibers -peripheral nuclei -no visible striations -possible to see individual myofibrils

Question 42

What are the characteristics of cardiac muscle?

Answer 42

-forms myocardium -involved in involuntary movement of the heartbeat

Question 43

What is the morphology of cardiac muscle?

Answer 43

-branched cardiomyocytes -one central nucleus per cell -intercalated discs in between cells -striated

Question 44

What are the characteristics of intercalated discs?

Answer 44

-connect adjacent cardiomyocytes -anchor the myofibrils -allow for rapid spread of excitatory stimuli

Question 45

What are purkinje cells?

Answer 45

cardiomyocytes that specialize in conduction of electrical signals

Question 46

How does cardiac muscle appear in longitudinal sections?

Answer 46

-can see branching -can see cross striations -can see intercalated discs

Question 47

How does cardiac muscle appear in transverse sections?

Answer 47

-cannot see branching, striations, or intercalated discs -will see irregular cells with central nuclei

Question 48

What is the main function of smooth muscle?

Answer 48

involuntary movement

Question 49

What is smooth muscle involved with?

Answer 49

-GI tract -uterus -blood vessels -skin -iris

Question 50

What is the morphology of smooth muscle?

Answer 50

-spindle-shaped cells -no cross-striations

Question 51

How will smooth muscle appear in transverse sections?

Answer 51

-variation in cell diameter -nucleus not seen in all cells

Question 52

How will smooth muscle appear in longitudinal sections?

Answer 52

-hard to distinguish individual cells -lots of parallel, oval-shaped nuclei

Question 53

How can smooth muscle be distinguished from dense irregular CT?

Answer 53

-smooth muscle has nuclei closely packed -dense irregular CT will have sparse nuclei