Exercise 6A

Classification of Tissues

The Tissue

• Multicellular organisms made up of tissues. • Tissues are the group of cells that are

similar in structure and function.• Study of tissues, Histology, complements a

study of gross anatomy and provides the structural basis for a study of organ physiology.

The Tissues

• Four primary tissue types are: – Epithelial tissue (Epithelium) – Connective tissue– Nervous tissue– Muscular tissue (Muscles)

The Organs

• Two or many types of primary tissues are grouped together to make organs; heart, lungs, kidneys

• Organs perform specific body functions

Epithelial Tissue

• Epithelium covers external body surface, the organs and lines the cavities inside organs.

• Functions- protection, absorption, filtration, excretion, secretion, and sensory reception.

Epithelial Tissue

• Characteristics: – Polarity (apical and basal surface)– Cellularity and specialized contacts– Supported by connective tissue (basement membrane)– Avascularity– Regeneration

Epithelial Tissue Types: Layer\Shape Flat (squamous) Cube Column (tall)

One layer Simple squamous

Simple cuboidal

Simple columnar

Multiple layers

Stratified squamous

Stratified cuboidal

Stratified columnar

Other types Transitional epithelium Pseudostratified columnar

Connective Tissue

• Found in all parts of the body, connects the tissues and organs

• Composed of specialized cells embedded within a non-living matrix.

• Matrix is combination of protein fibers (collagen, elastin, & reticulin) and ground substance (interstitial fluid, cell adhesion proteins, & proteoglycans)

• Functions: structural framework, protection, support, energy storage, immunity

Connective Tissue Classification:

1. Connective tissue proper

i. Loose connective tissue

ii. Dense connective tissue

a. Areolar connective tissue; mucous membranesb. Adipose connective tissue; hypodermis of skinc. Reticular connective tissue; bone marrow

a. Dense regular connective tissue; tondonsb. Dense irregular connective tissue; dermis of

skin

2. Supporting Connective Tissue

i. Cartilage

ii. Bone

a. Hyaline cartilage; trachea, ribs, ends of long bonesb. Elastic Cartilage; external ear, epiglottisc. Fibrous cartilage; intervertebral disks, knee joint

a. Osseous connective tissue; bones

3. Fluid Connective tissue

a. Blood ; blood vessels b. Lymph; lymph vessels

1. Loose Connective Tissuea. Areolar connective tissue

1. Loose Connective Tissueb. Adipose connective tissue

1. Loose Connective Tissuec. Reticular connective tissue

2. Dense Connective Tissuea. Dense regular connective tissue

2. Dense Connective Tissueb. Dense irregular connective tissue

1. Cartilage Connective Tissuea. Hyaline cartilage

1. Cartilage Connective Tissueb. Elastic cartilage

1. Cartilage Connective Tissuec. Fibrous cartilage

2. Osseous Connective Tissuea. Bone

3. Fluid connective tissuea. Blood

Muscular tissue

• Muscle tissue is relatively long slender cells containing contractile protein actin and myosin

• Muscle is both excitable and contractile • Function: movement • Types:

a. Skeletal b. Smooth c. Cardiac

Nervous tissue

• Tissues of the nervous system• Composed of two cell population

– Nerons – Neuroglial cells

• Neurons are functional excitable cells

• Glia are supporting cells with variety of functions

• Functions: provides integration and communication between body systems on a relatively fast, short time scale.