Tissue: types and level of organization | ppt

December 21, 2012 | By | Reply More

Tissue: types and level of organization | ppt

Power point presentation | lecture slide

Size: 670 KB



Tissue Level of Organization



Tissue Level of Organization

Tissues are groups of similar cells and extracellular products that carry out a common function.

4 Types of Tissues

epithelial tissue

connective tissue

muscle tissue

nervous tissue


Epithelial Tissue

Lines every body surface and all body cavities.

Forms both the external and internal lining of many organs.

Constitutes the majority of glands.

Composed of one or more layers of closely packed cells that form a barrier between two compartments having different components.

Little to no extracellular matrix.

No blood vessels penetrate an epithelium.


Characteristics of Epithelial Tissue: Cellularity

Composed almost entirely of cells bound closely together by different types of cell junctions.

Characteristics of Epithelial Tissue: Polarity

Apical surface (free, or top, surface)

Intercellular junctions

Basal surface (fixed, or bottom, surface)


Characteristics of Epithelial Tissue: Attachment

The basal surface of an epithelium is bound to a thin basement membrane.


Characteristics of Epithelial Tissue: Avascularity

Lack blood vessels.

Nutrients obtained either directly across the apical surface or by diffusion across the basal surface.


Characteristics of Epithelial Tissue: Innervation

Some epithelia are richly innervated to detect changes in the environment at that body or organ surface.

Most nervous tissue is in the underlying connective tissue.


Characteristics of Epithelial Tissue: Regeneration Capacity

Frequently damaged or lost by abrasion and is replaced via high regeneration capacity.

Continual replacement occurs through the divisions of the deepest epithelial cells (called stem cells) near its base.


Functions of Epithelial Tissue


Regulation of materials into and out of the organ or tissue

Produce secretions

Endocrine glands

Exocrine glands

Functions of Epithelial Tissue

Nerve endings detect changes in the external environment at their surface.

Continuously supply information to the nervous system concerning touch, pressure, temperature, and pain.


There are four types of cell junctions:

tight junctions

adhering junctions


gap junctions

Endocrine Glands

Lack ducts and secrete their products directly into the interstitial fluid and bloodstream.

Hormones act as chemical messengers to influence cell activities elsewhere in the body.

Exocrine Glands

Usually maintain their contact with the epithelial surface by means of a duct.

Duct secretes materials onto the surface of the skin or onto an epithelial surface lining an internal passageway.


Classification of Exocrine Glands

Form and structure (morphology)

simple glands vs. compound glands

Type of secretion

tubular vs. acinar ducts

Method of secretion

tubuloacinar gland




Secretion Types

Serous glands produce and secrete a nonviscous, watery fluid, such as sweat, milk, tears, or digestive juices.

Mucus glands secrete mucin, which forms mucus when mixed with water.

Mixed glands, such as the two pairs of salivary glands inferior to the oral cavity, contain both serous and mucus cells, and produce a mixture of the two types of secretions.

Merocrine Glands

Also called eccrine glands, package their secretions in structures called secretory vesicles which travel to the apical surface of the glandular cell and release their secretion by exocytosis.

The glandular cells remain intact and are not damaged in any way by producing the secretion.



Holocrine Gland

Secretion is produced through the destruction of the secretory cell.

Lost cells are replaced by cell division at the base of the gland.

Apocrine Gland

Secretion occurs with the “decapitation” of the apical surface of the cell and the subsequent release of secretory product and some cellular fragments.

Examples:  the mammary glands and some sweat glands in the axillary and pubic regions



Connective Tissue

Most diverse, abundant, widely distributed, and microscopically variable of the tissues.

Designed to support, protect, and bind organs.

Binds body structures together.

Basic Components of CT

All CT share three basic components:


protein fibers

ground substance


Components of CT: Cells

connective tissue proper contains fibroblasts,

fat contains adipocytes,

cartilage contains chondrocytes, and

bone contains osteocytes.

Many CT’s contain white blood cells such as macrophages, which phagocytize foreign materials.


Components of CT: Protein Fibers

Most contains protein fibers throughout the tissue.

Strengthen and support connective tissue.

Type and abundance of these fibers varies depending on function.


Components of CT: Protein Fibers

Three basic types of protein fibers:

collagen fibers are strong and stretch-resistant

elastic fibers are flexible and resilient

reticular fibers form an interwoven framework



Components of CT: Ground Substance

Cells and the protein fibers reside within a material called ground substance.

Nonliving material produced by the connective tissue cells.

Primarily consists of molecules composed of protein and carbohydrate and variable amounts of water.

May be viscous (blood), semisolid (cartilage), or solid (bone).



Functions of Connective Tissue

Physical protection

Support and structural framework

Binding of structures





Development of Connective Tissue

The primary germ layer mesoderm forms all connective tissues.

There are two types of embryonic connective tissue:


mucous connective tissue

Classification of Connective Tissue

The connective tissue types present after birth are classified into three broad categories:

connective tissue proper

supporting connective tissue

fluid connective tissue

The Resident Cells of the Connective Tissue Proper



Fixed macrophages

Mesenchymal cells


The Wandering Cells of the Connective Tissue Proper

Mast cells

Plasma cells





2 Broad Categories of CT

Loose connective tissue

Dense connective tissue

based on the relative proportions of cells, fibers, and ground substance


Supporting Connective Tissue

Cartilage and bone

Form a strong, durable framework that protects and supports the soft body tissues.

Extracellular matrix contains many protein fibers and a ground substance that ranges from semisolid to solid.



Fluid Connective Tissue

Blood is a fluid connective tissue composed of cells called formed elements.

erythrocytes (red blood cells)

leukocytes (white blood cells)


erythrocytes transport oxygen and carbon dioxide between the lungs and the body tissues

leukocytes mount an immune response

platelets are involved with blood clotting


Muscle Tissue

Responds to stimulation from the nervous system causing them to shorten.

Produce voluntary and involuntary movement.

Nervous Tissue

Sometimes termed neural tissue.

Consists of neurons, or nerve cells, and glial cells that support, protect, and provide a framework for neurons.



Detect stimuli, process information quickly, and rapidly transmit electrical impulses from one region of the body to another.

Prominent cell body functions in control; information processing, storage, and retrieval; internal communication.



Processes extend from the nerve cell body.




Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Category: Medical, Powerpoint

WARNING: Any unauthorised use or reproduction of  www.neuronarc.com content for commercial or any purposes is strictly prohibited and constitutes copyright infringement liable to legal action.