A&P Lab - Class 5: Histology I (epithelial and connective tissues)

Chemical - cellular - tissue - organ - system - organism

Cellular

False. Cells do not operate independently, they work together.

A tissue which covers the body, lines body cavities, and forms glands

A tissue which binds and supports various organs

Contractile tissue

Initiates and conducts electrochemical impulses

Epithelial, connective, muscular, nervous

The instrument that sections slide tissues

False. Some slides may be used to examine more than a single tissue type

Simple squamous epithelium

Areas with diffusion (and gas exchange). Ex:

• The heart

• Blood vessels

• Lymphatic vessels

• Forming capillary walls

Simple squamous

Secretion and absorption. Ex:

• Thyroid gland

• Kidney tubules

• Ducts of many glands

Absorption and secretion. Ex:

• Stomach

• Small and large intestines

• Ducts if various glands (line)

Simple columnar epithelia

They produce mucus which acts as a lubricant and protective barrier. Very abundant in some parts of the digestive tract.

Bottom cells (closer to basement membrane) are often cuboidal, but top cells (closer to apical surface) are often squamous

In areas of the body that are subject to “wear and tear”

Nonkeratinized: Absence of keratin Keratinozed: Presence of keratin This can be applied to stratified squamous epithelium

Dead

Skin

The urinary bladder, the urethra, the upper portion of the urethra. The thickness of this epithelium changes as it is subject to pressure.

Secretion. Found beneath the covering epithelia as single cells/cluster cells

To produce and secrete substances into ducts that open onto surfaces (exocrine glands) or secrete substances into body fluids (endocrine glands)

Exocrine: release onto surfaces Endocrine: secrete into body fluids

Merocrine (eccrine).

• Salivary glands

• Sweat glands of the skin

• Pancreatic glands

Apocrine glands.

• Mammary glands

Holocrine glands

• Sebaceous glands of the skin

Connective tissue

Mechanical binding and support, circulation of body fluids, insulation, storage of food reserves, inflammation

• Cells

• Protein fibres

• Ground substance

Extracellular matrix of connective tissues

Avascular

• Areolar (loose) connective tissue

• Adipose connective tissue

• Reticular connective tissue

• Dense regular connective tissue

• Cartilage

• Bone

False. It varies from fluid, to gel, to solid.

• Glycosaminoglycans (GAG) such as sulphate and hyaluronic acid.

• Proteoglycan

• Adhesive glycoproteins

Immature

Mature

Secrete matrix and are actively mitotic

Maintaining the matrix. Are less active

• Collagen

• Elastic

• Reticular fibres

Actively mitosis cell that secreted ground substance and fibers

Has coarse, dark-staining granules (in the cytoplasm). Secrete heparin and histamine

Large and irregularly shaped phagocytize cells. Arise from monocytes (type of white blood cell). Wander through connective tissue where they engulf and destroy bacteria, foreign particles, and dead/dying body cells.

A chemical that inhibits blood clotting

A chemical that increases blood flow by dilating blood vessels

Internal framework of the spleen, liver, bone marrow, and lymph nodes. Also closely associated with blood vessels and nerves

• Fibroblasts (reticular cells)

• White blood cells

• Macrophages

Short, thin branched network of collagen-like fibres

A large internal lipid droplet which displaces the nucleus to the edge of the cell

An abundance of fibers

• Regular

• Irregular

They have the same structural components, but dense irregular’s bundles of collagen fibers are much thicker and run in several directions

In the skin dermis. Forms fibrous coverings around organs such as kidney, muscles, bones, and nerves.

• Hyaline cartilage

• Elastic cartilage

• Fibrocartilage

Perichondrium

Dense connective tissue.

Hyaline cartilage

Hyaline cartilage

In the gel-like matrix

• Articular surfaces of bones

• Ends of the ribs

• Part of the nasal septum

• Larynx

• Trachea

• Bronchi

Fibrocartilage is less organized than other cartilage types, and it lacks a perichondrium

It provides strong support and can withstand heavy pressure. It forms pads, the vertebral discs between the individual vertebrae and the knee menisci between the tibia and femur. Also forms pubic symphysis (the joint between the pubic bones of the pelvis)

Support and protection. Provide cavities for fat storage and synthesis of blood cells. Storehouse for the minerals, calcium, and phosphorus required for various functions.

• Spongy (cancellous)

• Compact

Cancellous: Found internally (generally at expanded ends of bone known as trabeculae). Compact: External layer of the bone. Is thickest along the length of the bone.

Bone marrow

Concentric rings of bone called lamellae around a central (Haversian) canal containing blood vessels and nerves

Osteocytes

In lacunae between lamellae

Vascular (highly)

A connective tissue layer surrounding the bone

They penetrate compact bone through transverse perforating (Volkmann) canals which connect to the central canals that run longitudinally through the bone.

Networks of small canals that radiate from each lacunae

Via their cytoplasmic extensions that occupy canaliculi.

Inorganic materials/salts determine the bone's density

Organic materials determine the bone's flexibility

Transitional epithelium

Simple columnar

Pseudostratified

Keratinized stratified squamous epithelium

Simple squamous

Cuboidal and columnar

Simple squamous

Stratified squamous

Reticular connective tissue

Areolar (loose) connective tissue

Dense regular connective tissue

Tendons

Ligaments

Bone is vascular and can continue to grow larger and larger. Cartilage is avascular and only has a "set" size to grow until. It receives its nutrients from diffusion which is not enough to grow extremely large.