Chapter 4: Histology (Part 2)

Where does CT arise from?

mesoderm in embryo

What is the stem cell of CT called? Where is it found?

mesenchyme/mesenchymal cell; found in mucus of umbilical cord

What does ECM consist of in CT?

protein fibers, ground substance, etc.

What does protein fibers in CT ECM consist of?

elastic fibers, collagen, reticular fibers

What does ground substance in CT ECM consist of?

mixed proteins and carbohydrates w/ variable amounts of salt and water

What are the functions of CT?

physical protection, support and structural framework, binding of structures, storage, transport, immune protection

What are the different classifications of CT?

fluid CT, supporting CT, CT proper

What are the subcategories of fluid CT, supporting CT, and CT proper?

fluid CT: blood
supporting CT: cartilage, bone
CT proper: loose and dense CT

What are cartilage cells called?

chondrocytes

What are bone cells called?

osteocytes

Lacuna

small spaces osteocytes and chondrocytes occupy

What is fluid CT referring to? What are its components?

blood; plasma, erythrocytes, leukocytes, platelets

What type of tissue is blood?

fluid CT

Another name for red blood cells

erythrocytes

Another name for white blood cells

leukocytes

Platelets

fragments of erythrocytes involved in blood clotting

Plasma

water ground substance containing protein fibers

What does fluid CT transport?

transports O2, CO2, hormones, nutrients, waste products, etc.

Aside from transportation, what else does fluid connective tissue do?

protects from infections and helps regulate temp

Loose CT

body’s packing material, found in space around organs (filling)

Dense CT

strong with protein fibers (mostly collagen) packed tightly together (connecting)

What type of tissue is cartilage?

supporting CT

Different types of cartilage

hyaline cartilage, fibro-cartilage, elastic cartilage

Hyaline Cartilage Location and Function

tip of nose;
trachea;
most of larynx,
costal cartilage;
epiphyseal (growth plates) and articular ends of long bones;
most of fetal skeleton

provides support

Fibro-cartilage Location and Function

intervertebral discs; pubic symphysis; menisci of knee joint

resists compression; acts as shock absorber on some joints

Elastic cartilage Location and Function

external ear; epiglottis of larynx

maintains shape while permitting extensive flexibility

What type of tissue is the bone?

supporting CT

Contents of bone ECM

collagen (protein fibers) and calcium salts

Bone function

provides lever for body movements, supports soft structures, protects organs, stores calcium and phosphorus; contains hemopoietic tissue and is site for hemopoiesis

Types of Loose CT

areolar CT, adipose CT, reticular CT

Areolar CT Location and Function

dermal papillae; subcutaneous layer; surrounds organs, nerve cells, some muscle cells, and blood vessels

protects tissues and organs; binds skin and some epithelial tissue to deeper tissue

Adipose CT Location and Function

subcutaneous layer; surrounds and covers some organs

stores energy; insulates, cushions, and protects

Reticular CT Location and Function

spleen, lymph nodes, and red bone marrow

provides stroma (positive framework) to lymphatic organs

Types of Dense CT

dense irregular CT, dense regular CT, elastic CT

Dense Irregular CT Location and Function

dermis, covers bone/cartilage/nerves/skeletal muscle

withstands stresses applied in all directions; durable

Dense Regular CT Location and Function

tendons; ligaments

attaches bone to bone (most ligaments) as well as muscle to bone (tendon); resists stress applied in one direction

Elastic CT Location and Function

elastic arteries (like aorta), trachea, vocal cords

allows stretching and recoiling