Histology Chapter 5

Connective Tissue

What is the Bible verse about taking a spiritual shower?

1 John 1:9

What is Dr. Blais’s favorite verse?

John 14:6

3 types of connective tissue:

1. connective tissue proper (CTP)

2. support

3. fluid

What is the most abundant and widely distributed tissue type in primary tissues?

connective tissue

What are the structural elements of connective tissue?

cells, fibers, ground substance

3 types of fibers in CT

collagen, elastic, reticular

What is ground substance?

unstructured material that fills the space between cells

What are the 6 functions of CT?

binding, protection, insulation/storage, transportation/immunity, motion, hemostasis

What two structures made of CT are used for binding?

tendons and ligaments

What structure of CT is used for insulation and storage?

fat

What structure of CT is used for transportation and immunity?

blood

What structure of CT is used for motion?

cartilage

What structure of CT is used for hemostasis?

platelets

2 subcategories of CTP:

dense and loose

3 types of dense CTP:

regular, irregular, elastic

3 types of loose CTP:

adipose, areolar, reticular

2 types of fluid CT:

lymph and blood

2 types of support CT:

bone and cartilage

What embryonic layer is connective tissue made of?

mesoderm

What are the cells of CT characterized by?

1. oval nuclei with prominent nucleoli and fine chromatin

2. many thin cytoplasmic processes

3. abundance and viscous extracellular matrix

What are cytoplasmic processes?

fibers being produced and exocytosed by a cell

What are the 6 cells of CT?

1. fibroblasts

2. adipocytes

3. macrophages

4. mast cells

5. plasma cells

6. leukocytes

Which of the 6 CT cells stay in the CT?

fibroblasts, adipocytes, and mast cells

Which of the 6 CT cells circulate the blood then move into CT?

plasma cells and leukocytes

Which of the 6 CT cells move through CT for a few days and usually die by apoptosis?

leukocytes

Which of the 6 cells originate from mesoderm? (it is only one)

fibroblasts

Which of the 6 cells originate from bone marrow?

all but fibroblasts

What are the most common cells in connective tissue?

fibroblasts

Active cells are called fibroblasts. What are inactive cells called?

fibrocytes

What does a fibroblast look like?

1. abundant and irregular branched cytoplasmic processes

2. ovoid large nucleus with large nucleolus

3. abundant RER and well-developed golgi

What does a fibrocyte look like?

1. smaller spindle shape with few processes

2. smaller and darker nuclei

3. less RER and acidophilic cytoplasm

In what two scenarios are fibroblasts activated?

body growth and tissue repair

During tissue repair, fibroblasts are targets for growth factor and produce _________ after undergoing mitosis.

collagen

What are 6 things that fibroblasts can secrete?

1. collagen fibers

2. elastic fibers

3. reticular fibers

4. glycosaminoglycans (GAGs)

5. proteoglycans

6. multiadhesive glycoproteins

Purpose of collagen fibers:

give tissues strength

Purpose of elastic fibers:

gives tissues flexibility

Purpose of reticular fibers:

gives tissues compartments and structure

Purpose of GAGs:

provide resistance to pressure bc water sticks to them

Purpose of proteoglycans:

major component of the animal ECM, the filler substance between cells

Purpose of multiadhesive glycoproteins:

act to stabilize ECM and link to cell surfaces

2 examples of mutliadhesive glycoproteins:

fibronectin and laminin

fibroblast

fibrocytes and fibroblasts

When tissue is destroyed, what cells are activated? What do they do?

fibroblasts are activated, undergo mitosis and begin producing collagen fibers to fill the space formed by the trauma

What to myofibroblasts produce?

both collagen and actin (which causes the scar to contract)

3 phases of wound healing:

1. scab formation

2. granulation tissue

3. scar tissue

What occurs when myofibroblasts are done with scar formation?

apoptosis

What can happen if myofibroblasts are not killed after scar formation is done?

fibrotic diseases like liver cirrhosis, keloids, or hypertrophic scars

What structure is this?

keloid

What has happened to this heart tissue?

it is scarred

What is granulation tissue?

new fibroblasts laying down tissues

Two types of hyperactive scars:

keloids and hypertrophic scars

What appearance does collagen have in a keloid?

bubble gum collagen appearance

What type of scar is this?

keloid

What type of scar is this?

hypertropic scar

What type of scar is this?

hypertrophic scar

What collagen types are found in hypertrophic scars?

type 3

What collagen types are found in keloids?

types 1 and 3

Fiber arrangement of hypertrophic scars:

parallel to epidermis

Fiber arrangement of keloid scars:

random to epidermis

Are myofibroblasts in hypertrophic vs keloid scars?

present in hypertrophic and absent in keloid

Cell number _______ in hypertrophic scars.

increases

Cell number _______ in nodules and ________ in periphery in keloid scars.

decreased; increased

What cell types are these?

adipocytes

Macrophages in the liver are called:

Kupffer cells

Macrophages in the brain are called:

microglia

Macrophages in the epidermis are called:

Langerhan cells

What do macrophages do?

phagocytize and pinocytos substances

What cell is this?

macrophage

Macrophage in lymph nodes are called:

dendritic cells

Macrophages in bone are called:

osteoclasts

What forms when lysosomes cannot properly break down debris anymore because of their age?

residual bodies

What forms inside of residual bodies?

lipofuscin

Inflammation for less than 72 hours is called _______.

acute

Inflammation for more than 72 hours is called ________.

chronic

What cell types are present in acute inflammation?

neutrophils and macrophages

What cell types are present in chronic inflammation?

B and T lymphocytes

Two types of acquired immunity:

artificial and natural

Two types of artificial/natural immunity:

active and passive

How might one get artificially acquired active immunity?

a vaccine

How might one get artificially acquired passive immunity?

antibodies injected into the immune system

How might one get naturally acquired active immunity?

getting the infection/contacting the pathogen

How might one get naturally acquired passive immunity?

antibodies given via breastmilk or across the placenta

What is the antibody in breast milk?

IgA

Mast cells are large, oval cells containing ________.

granules

What type of granules do mast cells contain?

metachromatic

List the 5 different mast cell granules:

heparin, histamine, serine protease, leukotrienes, eosinophil and neutrophil chemoxatic factors

Function of heparin:

anticoagulant

Function of histamine:

promotes increased vascular permeability and smooth muscle contraction

Function of serine protease:

activates various mediators of inflammation

Function of leukotrienes C4, D4, E4:

triggers smooth muscle contraction

What antibody must bind to mast cells to trigger degranulation?

IgE

What cell type is this?

mast cell

In what two locations are mast cells most abundant?

respiratory mucosa and perivascular (small vessels of the skin)

Binding of two or more IgE molecules to a mast cell activates the release of _______ and ________.

histamine and heparin

A severe allergic reaction can cause what life-threatening condition?

anaphylaxis

Mastocytosis

abnormal high amount of mast cells produced

What is the cure for mastocytosis?

there is no cure, only treatments for the symptoms

What is the treatment of choice for mastocytosis?

Zafirlukast

Two types of leakage from normal blood vessels:

transudate and exudate