Physiology- Muscles and Connective Tissue

What are the two general components of all connective tissue?

cells and extracellular matrix

What are the two components of a connective tissue cell?

Fibroblasts and immune cells

What is another word for fibroblasts?

fibrocytes

What is the job of a fibroblast?

make the extracellular matrix

What happens if a fibroblast is activated?

It becomes a myofibroblast

What is the job of a myofibroblast?

aids in wound healing by using contractile fibers to shrink the wound

Where are myofibroblasts located?

damaged tissues

What is the job of an immune cell in connective tissue?

Patrol the tissue to identify invaders

What are the two components of the extracellular matrix?

Fibers and ground substance

What color do fibers stain in extracellular matrix of connective tissue?

pink

What are the two types of connective tissue fibers?

Collagen and elastin

What two things do fibroblasts produce?

Collagen and ground substance

What is the most common connective tissue fiber type?

collagen

What is the job of collagen?

Have tensile strength due to braided structure

How many different types of collagen are there?

28

What is collagen type 1?

main structural collagen of fibrous tissues such as ligaments and tendons

What is collagen type 2?

Main structural collagen of hyaline cartilage

What is collagen type 3?

meshwork of fleshy organs

What is collagen type 3 also known as?

Reticulin

How can you see reticulin?

Use special reticulin stain

What is type 4 collagen?

collagen of basement membrane

What is the job of elastin?

stretch and recoil

How do we not get squished under gravity?

Ground substance

What is the job of ground substance?

to attract water and form a gel for compression resistance so we dont get squished by gravity

Where is elastin found?

places that need stretch such as nuchal ligament and urinary bladder

How does elastin appear on slide?

pink

How does ground substance appear on slide?

Clear

What is ground substance made of?

proteoglycans

What makes up a proteoglycan?

Glycosaminoglycans (bristle) and protein backbones (brush backbone)

What is the purpose behind proteoglycans?

to keep water from pooling at feet

What is the main cell type of connective tissue proper?

fibroblasts

What is the main fiber type of connective tissue proper?

collagen

What is the purpose of connective tissue proper?

hold together and support tissues

What are the two types of connective tissue proper?

Dense and loose

What are the two types of dense connective tissue proper?

Regular and irregular

What are the 4 characteristics of loose connective tissue?

1. LOTS of ground substance
2. few collagen fibers
3. sparse fibroblasts
4. form mesentary

What is mesentary?

guts

What are the three characteristics of dense, irregular connective tissue?

1. LOTS of collagen fibers arranged IRREGULAR
2. less ground substance
3. few fibroblasts

What is the purpose of dense, irregular connective tissue?

resists movement in MANY directions

Where is dense, irregular connective tissue?

dermis, submucosa, organ capsule

What are the two biggest differences between dense regular and dense irregular connective tissue?

1.resisting movement in many vs one direction
2. Parallel collagen fibers vs irregular collagen fibers

What are the three characteristics of dense, regular connective tissue?

1. LOTS of collagen fibers (parallel configuration)
2. less ground substance
3. Few fibroblasts

What is the purpose of dense, regular connective tissue?

resist movement in ONE direction

Where is dense, regular connective tissue?

Found in tendons, ligaments, aponeurosis

What is similar between dense regular and dense irregular connective tissue?

they both have little ground substance and little fibroblasts

What are two characteristics of dense, irregular connective tissue on slide?

Sparse nuclei and TONS of cytoplasms

What are the special fibroblasts of reticular connective tissue?

reticular cells

What are the two types of adipose tissue?

White and Brown

What is the cell type of adipose tissue?

adipocyte

What are the synonyms for an adipocyte?

lipocyte/fat cell

Where are white and brown fat cells in the body in relation to one another?

Stay away from one another

What are the three functions of white adipose tissue?

1. energy storage
2. impact protection
3. insulation

Where is white adipose tissue found?

Everywhere

What does white adipose tissue look like on slides?

Bubblewrap

What is the structure of white adipose tissue?

single peripheral nucleus, signet ring shaped, one large lipid droplet

What is the function of brown adipose tissue?

thermoregulation by creating heat rather than ATP

Where can you find brown adipose tissue?

neonates, hibernating animals, rodents

What is the cell type of brown adipose tissue?

brown adipocyte

What is the structure of brown adipose tissue?

multiple, small lipid droplets; more mitochondria; plumper looking nucleus

What are the three types of muscles?

skeletal, cardiac, smooth

What are the synonyms for muscle cells?

muscle fibers, myofibers, myocytes

What are the three contents of all muscle cells?

nuclei, cytoplasm, contractile filaments

What are the contractile filaments?

Actin and myosin

How do contractile filaments work?

they slide past one another

What is smooth muscle for?

Involuntary movement

Where is smooth muscle found?

GI, uterus, blood vessels, skin, iris

What cell shape is found in smooth muscle?

Spindle cells

Which muscle types have visible striations?

Cardiac and skeletal

What is visible striation mean?

Filaments arranged orderly

What is the purpose of skeletal muscle?

Primarily voluntary movement (locomotor muscles and some sphincters), SOME involuntary movement (diaphragm)

What is the organization of skeletal muscles?

muscle> fasicle> myofiber> myofibril> filament

What surrounds each level of skeletal muscle organization?

connective tissue

What are myofibers made of?

many peripheral nuclei, sarcoplasmic reticulum, complex cell membrane, parallel myofibrils

What is the sarcoplasmic reticulum of a myofiber for?

coordination of contraction

What is a sarcomere?

contractile unit (actin and myosin)

What is the term for multiple peripheral nuclei?

syncytial cells

What is the purpose of cardiac muscle?

Involuntary movement regarding the heart beat

What is the myocardium composed of?

cardiac muscle

What are cardiomyocytes?

short, branched cardiac muscle cells that can contract

What is special about cardiac muscle cells?

They have one central nuclei

What are intercalated discs?

connect adjacent cardiomyocytes which anchors myofibrils

What are cardiac purkinje fibers for?

specialize in electrical signal conduction for contracting cardiomyocytes

What do several muscle filaments make up?

a myofibril

What do several myofibrils make up?

myofiber

What do several myofibers make up?

fasicle

What do several fasicles make up?

a muscle

What is made up of fibers and ground substance?

Extracellular matrix

What are fibroblasts and immune cells part of?

Connective tissue

What are some examples of where you can find reticulin?

lymph node****, spleen, liver, brain

***= in her slide and not a known organ you think of

What cell type is found in adipose tissue?

adipocyte

What is the shape of fibroblasts?

spindle shaped

Where can you find loose connective tissue?

Mesentary (guts)

Where can you find dense, irregular connective tissue?

skin, submucosa, organ capsules

Where can you find dense, regular connective tissue?

tendons, ligaments, aponeurosis

Where can you find reticulin?

parenchymal organs such as liver, spleen, and lymph node

Where will you find elastin?

blood vessels, vocal cord, nuchal ligament

What do actin and myosin together make up?

sarcomere

What is collagen?

the fiber within connective tissue

What type of connective tissue has more collagen fibers?

dense connective tissue

What connective tissue type has a smaller amount of collagen fibers?

loose connective tissue