Histology: Connective Tissue Lecture 1

Mesenchyme

Adipocytes, or Adipose Tissue, is derived from _____________ Embryonically.

Mesenchyme

Connective tissues of adults is derived from an embryonic tissue called _______________, which is derived from embryonic mesoderm.

Connective tissues may be vascular (bone) or avascular (cartilage, for example).

Is connective tissue vascular or avascular?

Fibroblasts

Regarding "Fibroblasts" of connective tissue... - These are the generic, or principle cell, of Connective Tissue. - Fibroblasts are responsible for synthesizing the ECM.

1. Resident (fixed) Macrophages 2. Elicited (wandering or free) Macrophages

Regarding 2 types of Macrophages of Adult Connective Tissue... 1. _______________________ macrophages (Figure 4-7a) are regular inhabitants of a particular tissue. 2. _________________________ macrophages (Figure 4-7b) circulate in the blood and migrate to where they are needed.

Extracellular Matrix (ECM)

Regarding Extracellular Matrix of Adult Connective Tissues... - The properties of a connective tissue are largely due to the properties of its ____________________________.

1. Macrophages

Regarding different cells of Adult Connective Tissue... 1. __________________ are derived from blood monocytes and are found in a variety of tissues. Their function is to phagocytose (engulf) foreign, dead and dying cells, and cellular debris.

1. Lymphocytes & Plasma Cells 2. Neutrophils

Regarding different cells of Adult Connective Tissue... Leukocytes (white blood cells) of various types may be seen in connective tissues, especially at the site of infection or inflammation. 1. Most commonly seen in healthy tissue preparations are _______________ and _________ ________. 2. ______________, another WBC, (Figure 4-12) have a granular cytoplasm and a segmented (lobed) nucleus. They are phagocytic.

Mast Cells

Regarding different cells of Adult Connective Tissue... _________ ________ (Figure 4-8) originate in the bone marrow, but occupy various connective tissues. These cells are large with prominent cytoplasmic, membrane-bound granules. The granules contain chemicals (such as heparin, histamine, chemotactic factors, and many others) that are involved in the inflammatory response. Release of the granules' contents is called degranulation.

Adipocytes

Regarding different cells of Adult Connective Tissue... ____________ are derived from mesenchymal cells and, perhaps, fibroblasts. They are specialized to store fat. Often, the fat is dissolved from the ______________ during slide preparation, so all that is seen is empty cells (Figure 4-9b).

Fibroblasts

Regarding different cells of Adult Connective Tissue... _____________ are derived from mesenchymal cells and are responsible for synthesis and maintenance of the matrix. Underscoring their relatively undifferentiated state, each ____________ can produce all elements of the extracellular matrix.

1. Regular Connective Tissue 2. Irregular Connective Tissue 3. Loose Connective Tissue & Dense Connective Tissue

Regarding types of Adult Connective Tissue... Fibrous connective tissues have traditionally been classified according to the arrangement and density of fibers... 1. ___________ connective tissues have the fibers oriented in the same direction. 2. The fibers of ____________ connective tissues are oriented in all directions. 3. The fibers of _________ connective tissues occur singly, whereas the fibers of ___________ connective tissues occur in bundles and are tightly packed together. Note: Although these categories will be used here, it should be realized that they represent extremes and that intermediate connective tissue types exist.

1. Energy Storage 2. Insulation 3. Protection of Visceral Organs 4. Energy Homeostasis.

Remember that earlier we learned that Adipose Tissue, is used for lipid (triglyceride) storage. What are some of the functions of Adipose Tissue?

Type 1 Collagen

Remember that there are 3 types of fibers that make up the ECM (Collagen, Reticular, Elastic). What are the main types of Collagen fibers? A) Type 1 Collagen Fibers: Most abundant type of Collagen.

1. White Adipose 2. Brown Adipose

There are 2 types of Adipose tissue, depending on if it's in a fetus or adult. 1. Adult Adipose is __________ Adipose. 2. Fetal Adipose is __________ Adipose.

Collagen & Elastin

We just learned that the 2 components of the Extracellular Matrix (ECM) are the Ground Substance & Fibers... Regarding the Fibers... - These fibers are made of protein and come in two basic types; ___________ & ___________.

Ground Substance Of ECM

We just learned that the 2 components of the Extracellular Matrix (ECM) are the Ground Substance And Fibers. Regarding the Ground Substance... - Ground substance is an amorphous, gel-like material composed of charged glycosaminoglycans and proteoglycans (mucoproteins) of various types. - The Ground Substance is liked a hydrated gel that allows rapid diffusion of nutrients, hormones, and more, between blood and cells, and between cells. - Because of this association, the ground substance is an essential participant in the transport of nutrients and wastes between the blood and other tissues. - Note that ground substance is not easily visualized in histological preparations.

Comprising the ECM are the... 1. Ground substance 2 Fibers

We just learned that the properties of connective tissue are largely due to the properties of its Extracellular Matrix (ECM). What are the 2 main components of an ECM?

1. Undifferentiated Mesenchymal Cells 2. Hematopoietic Stem Cells *Look to included photo to see what all these can differentiate into.

What does Connective Tissue rise from, embryonically?

Adipose Tissue

What is Adipose Tissue? - Put simply, Adipose tissue is fat. Adipose tissue can be found all of the body, but more so in some parts compared to others. - Adipose cells, called Adipocytes are used for lipid (triglyceride) storage.