Lecture 16- Connective Tissue and Muscle Flashcards
A tissue type of cells embedded in extracellular matrix, NOT muscle, epithelial, or nervous tissue
Connective tissue
What type of cells make the extracellular matrix?
Fibroblasts
What are the two parts of the ECM
fibers and ground substance
What are myofibroblasts
Activated fibroblasts that promote healing
What are two types of fibers found in the ECM?
Collagen and ellastin
What is the main quality of collagen?
Tensile strength
Where is type I collagen found?
fibrous supporting tissues (bone, ligaments, skin, and tendons)
Where is Type II collagen found?
Hyaline cartilage
What is another name of Type III collagen?
Reticulin
Where is Type III collagen found?
supporting network for fleshy organs
Where is Type IV collagen found?
basement membranes
What is the main job of elastin?
Bounce, stretch, and recoil
Where is elastin found?
Skin, bid arteries, bladder, nuchal ligament, external ear, vocal cords
What is ground substance?
A gel-like substance surrounding fibroblasts
What does ground substance do?
Protects from compression and allows nutrient/waste transport
Structure of ground substance
Hyaluronic acid network to attract water
Proteoglycan limbs to add volume
Glycosaminoglycan branches to bind the ECM together
Types of connective tissue
Loose
Dense (regular/irregular)
reticular
Elastic
Adipose
Bone
Loose connective tissue composition and location
Lots of ground substance, few collagen fibers.
Found surrounding vessels and nerves.
Dense irregular connective tissue composition and location
Lots of irregularly arranged collagen fibers, few cells.
Found in the dermis and submucosa of intestines
Dense regualar connective tissue composition and location
Lots of parallel collagen fibers, few cells and ground substance
Located in tendons, ligaments, and aponeuroses
Reticular connective tissue composition and location
Meshwork of reticulin, few cells
Found supporting cells in parenchymal organs
Elastic connective tissue composition and location
Lots of elastin
Found in arteries, nuchal ligament, vocal cords…
Adipose tissue composition and location
Adipocytes, with either a clear signet-ring shape (white) or multilocular droplets with central nuclei (brown)
Found everywhere
Name of muscle cells
Muscle fibers/myofibers/myocytes
Order of muscles
Muscle –> fascicles –> myofibers –> myofibryls –> filaments –> sarcomeres
Where are nuclei located in myofibers?
Many nuclei per cell, located peripherally
What is the myofiber cell membrane called?
Sarcolemma
What are the borders of the sarcomeres?
Z discs
What is the name of dark bands and what are they made of?
A bands
myosin
What is the name of light bands and what are they made of?
I bands
Actin
In what species does cardiac muscle also line the pulmonary veins?
Rodents
Low electrical resistance between cardiomyocytes is due to-
Intercalated discs
What is the difference between cardiac and skeletal muscle on microscopy?
Cardiac has branching, intercalated discs, more cytoplasm, and centrally located nuclei
Why doesn’t smooth muscle have striations?
Actin and myosin crisscross instead of forming parallel lines
