Lecture 4 - connective tissue

What layer is muscle derrived from?

mesoderm

What are the 3 types of muscle?

skeletal, cardiac, and smooth

Where is skeletal muscle found?

attatched to bones, anal sphincter, diaphragm, and some of the esophagus

What is the order of muscle conformation?

myofibril, myocyte/myofiber, fasicle, and muscle

Where do striations come from?

the parallel arrangement of actin and myosin in the sarcomere

What is the purpose of skeletal muscle?

voluntary movement except diaphragm and esophagus

What are the nuclei in a myocyte?

multiple and peripheral

What is the purpose of cardiac muscle?

involuntary movement for a heartbeat

Where is cardiac muscle found?

in the myocardium (heart wall)

What is the name of a heart muscle cell?

cardiomyocyte

How do cardiomyocytes appear?

they are branched cells with a single central nucleus and parallel arrangements of actin and myosin to create striations

What seperates cardiomyocyte cells?

intercalated discs

What are purkinje fibers?

specialized cardiomyocytes that conduct the electrical impulses through the heart. They do not appear striated. These were discovered by the same person who discovered purkinje cells in the brain

What is the purpose of smooth muscle?

involuntary movement with slow and sustained contraction

Where is smooth muscle located? - 1x a wk

GI tract, blood vessels, uterus, skin (arrector pili muscle), and iris of mammals

What is the name of a smooth muscle cell? - 1x a wk

leiomyocyte

What is the appearence of smooth muscle cells? - 1x a wk

long spindle shape with a single central nucleus

Is smooth muscle striated and why? - 1x a wk

no because the actin and myosin fillaments are arranged in a non parallel network

What are the three types of connective tissue and what are they made of?

collagen, elastin, and reticulin. All are made from fibroblasts

Can you identify fibroblasts?

no, they are nondescript spindle cells that are identified by their product

What is collagen?

the most common and important type of connective tissue that are strong extracellular fibers made of protein

What stains are used for collagen?

Trichrome stain colors collagen blue and muscle red. H and E stain colors collagen red

Where do you find collagen?

around blood vessels, dermis, submucosa of intestines, basment membrane (IV), tendons and ligaments EVERYWHERE

What is elastin?

protein based tissue that provides elasticity

Where is elastin found?

nuchal ligament, vocal cords, elastic arteries, lung, trachea, external ear, etc.

What stain is used for elastin?

elasrin stain (silver stain) highlights the fibers black. The fibers appear squiggly when relaxed and long/strain under tension

What is reticulin?

a net arrangement of thin fibers to support the cells of perenchymal organs

What is muscle?

tissue that specializes in contraction that results in movement

What stain is used for reticulin?

reticulin stain (silver stain) highlights the fibers black

What is connective tissue?

tissues that function to bind together and/or support other tissues

What is white adipose tissue?

made of white adipocytes that are large cells with a clear droplet and peripheral nucleus. Used for energy storage, thermal insulation, and impact protection

Where do you find white adipose?

subcutis, mediastinum, mesentery, retroperitoneum, epicardium, bone marrow

What is brown adipose tissue?

made of brown adipocytes that have many small clear lipid droplets with a cenral to paracentral nucleus. They also have many mitochondria. Converts fat into heat using the mitochondria

Where is brown adipose tissue found?

neonates, rodents, and hibernating animals