Human TissuesTissue Differentiation

Anatomy and Physiology 1A. DeVault

Tissue Defined

•Tissues are a group of cells that have a similar shape and purpose.•Tissues become organs that become organ systems.•Tissues begin to form as embryonic stem cells.

Tissue Types

•Epithelial•Connective•Muscle•Nervous

Epithelial Tissue

3 types of epithelial tissue•Squamous•Cuboidal•Columnar

Descriptive layersSimple – one layerStratified – more than one layer

Characteristics of Epithelium

• Polar surfaces•Apical free surface• Basement membraneAvascularPronounced nucleusMitotic activityClosely packed together

Identifies by number of cells and shape of cell

Epithelial Cell Shapes

Simple Squamous Epithelia

Simple Cuboidal Epithelia

Simple Columnar Epithelia

Stratified Squamous Epithelia

Pseudostratified ciliated columnar epithelia

Glandular Epithelial

•A gland is one or more cells that produce and secrete a specific product. •The product is always a water-based fluid (aqueous) and usually contains proteins (the product is referred to as a secretion).

•Secretion is considered an active process.

Glands are Classified

• Endocrine • Endocrine glands are also called ductless glands because eventually, they lose their ducts. • They produce hormones (chemical messengers ) and secrete them directly into the bloodstream.

• Exocrine • Exocrine glands secrete their products onto the skin or into body cavities. • Products secreted by exocrine glands include sweat, oil, mucous, bile, and milk*.

Modes of Secretion

•Merocrine glands– secrete their products by exocytosis during production (the pancreas and most mucus/salivary glands belong to this class).•Apocrine: sweat gland

•Holocrine glands– accumulate their products until they rupture and die. •Holocrine glands secrete dead cell fragments along with their main product. (oil glands)

Glandular Epithelial

Connective Tissue

Characteristics of Connective Tissue•Connective tissue supports and binds other

tissues of the body.•All connective tissue apart

from blood and lymph consists of three main components: • fibers (elastic and collagenous fibers),• ground substance and cells.

• The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leucocytes.

Connective Tissue

6 Types• Loose connective tissue• Dense connective tissue• Adipose• Blood• Cartilage• Bone

Loose Connective Tissue

Areolar C.T.

Dense Connective Tissue

Fibrous C.T.

Adipose Tissue

Blood

Blood smear

Cartilage

Cartilage types

•Hyaline•Elastic•Fibrocartilage

Hyaline

Elastic

Fibrous

Bone

Muscle Tissue

3 types of muscle tissue

•Cardiac –heart

•Skeletal – attached to bones

•Smooth – internal organs and blood vessels

Cardiac Muscle

Skeletal Muscle

Smooth Muscle

Nerve Tissue