Lecture 16 - Connective Tissues

Question 1

Connective tissues

Answer 1

Most abundant and widely distributed of the primary tissues.

Functions: binding and support, protecting, insulating, storing reserve fuel, and transporting substances (blood).

Four main classes: connective tissue proper, cartilage, bone and blood.

Question 2

Characteristics of connective tissues

Answer 2

All connective tissue arises from an embryonic tissue called mesenchyme (Greek, “middle-filling”).

Most connective tissue is highly vascularized, but tendons and cartilage are not.

composed mainly of nonliving extracellular matrix (a protein-sugar mesh) that separates the cells of the tissue. This matrix supports cells so that they can bear weight and withstand tension.

Question 3

Three main elements of connective tissue

Answer 3

Ground substance
Cells
Fibres

Question 4

What makes up extracellular matrix?

Answer 4

Ground substance and fibres together

Question 5

What are blast cells?

Answer 5

Immature “blast” cells actively secrete ground substance and extracellular fibres.

Fibroblasts are found in connective tissue proper
chondroblasts are found in cartilage
osteoblasts are found in bone

Question 6

What are mature cyte cells?

Answer 6

Mature “cyte” cells (example: fibrocytes) are less active and help maintain the health of the matrix

Question 7

Fat cells

Answer 7

Store nutrients

Question 8

White blood cells

Answer 8

as neutrophils, eosinophils and lymphocytes (including plasma cells), respond to tissue injury.

Question 9

Mast cells

Answer 9

initiate a local inflammatory response against foreign microorganisms they detect.

Call WBCs if there is a problem

Question 10

Macrophages

Answer 10

phagocytic white blood cells that “eat” dead cells and microorganisms as part of their function in the immune system.

Eat things that don’t look right

Question 11

What is a Ground substance?

Answer 11

an unstructured gel-like material that fills the space between the cells.

Question 12

Collagen fibres

Answer 12

extremely strong and provide high tensile strength to the connective tissue.

Ex. Scar tissue

Question 13

Elastic fibres

Answer 13

contain elastin, which allows them to be stretched and to recoil.

Question 14

Reticular fibres

Answer 14

fine, collagenous (but different from collagen) fibres that form branching networks where connective tissue contacts other types of tissues.

Question 15

Areolar connective tissue

Answer 15

serves to support and bind body parts, contain body fluids, defend against infection, and store nutrients.

It is the universal packing material between other tissues.

Ex. Under skin

Question 16

Adipose (fat) tissue

Answer 16

a richly vascularized tissue that functions in nutrient storage, protection, and insulation.
Almost entirely cells
Brown fat uses lipids to produce heat. (babies have more, harder to maintain body heat without)

Question 17

Reticular connective tissue

Answer 17

forms the internal mesh-like stroma that supports the lymph nodes, the spleen and bone marrow.

Question 18

Dense regular connective tissue

Answer 18

contains closely packed bundles of collagen fibres running in the same direction and makes up tendons and ligaments.

No blood vessels

Strong when pulled in direction they are meant to be pulled in

Question 19

Dense irregular connective tissue

Answer 19

contains thick bundles of collagen fibres arranged in an irregular fashion and is found in the dermis

Collagen going in more than one direction

Question 20

Elastic connective tissue

Answer 20

found in select locations and is more stretchy than dense regular connective tissue.

Expand and rebound

Question 21

Cartilage

Answer 21

Cartilage grows from chondrocytes, lacks nerve fibres, and is avascular.

Matrix secreted from chondroblasts (during growth) and chondrocytes (as adults).

Chondrocytes found in cavities called lacunae (empty spot, lake or pool).

Because it is avascular, cartilage receives nutrients from the membrane surrounding it, called the perichondrium.

Question 22

Hyaline cartilage

Answer 22

the most abundant skeletal cartilage and includes the articular, costal, respiratory, and nasal cartilages.

Provides firm support with some pliability. It is found at tips of long bones, nose, trachea, larynx, and cartilage of the ribs

Question 23

Elastic cartilages

Answer 23

more flexible than hyaline and are located only in the external ear and the epiglottis of the larynx.

found where strength and exceptional stretch are needed, such as the external ear and epiglottis

Question 24

Fibrocartilage

Answer 24

located in areas that must withstand a great deal of pressure or stretch, such as the cartilages of the knee and the intervertebral discs.

Question 25

Cartilage growth

Answer 25

Appositional growth occurs when cartilage gets bigger from the perichondrium. New matrix is laid down on the surface of the cartilage.

Interstitial growth occurs when the cartilage matrix expands from the middle due to division of lacunae-bound chondrocytes and secretion of matrix within the cartilage.

Question 26

Calcification of cartilage

Answer 26

occurs during normal bone growth in youth, but can also occur in old age.
Hardened cartilage is not the same as bone.

Question 27

Bone (osseous) tissue

Answer 27

has an exceptional ability to support and protect body structures due to its hardness, which is determined by the additional collagen fibres and calcium salts found in the extracellular matrix

Question 28

Blood (connective tissue)

Answer 28

classified as a connective tissue because it develops from mesenchyme and consists of blood cells and plasma protein fibres surrounded by blood plasma.
The fibres are soluble proteins that precipitate during blood clotting