A patient presents with severe digestive abnormalities. Upon initial examination, CBC ruled out infection and X-rays revealed no bowel obstructions. Doctors begin to suspect problems within the enzymes, mainly from the liver. How do you proceed to diagnose?

Biopsy

Terminology

• Tissues – group of cells that carry out specialized activities– Histo = Tissue

-ology = study of

• Pathologists – Study of cells and tissue; diseased– Patho = disease

Four Main Types

• Epithelial – Body surfaces, hollow

organs, glands

• Connective– Binds organs together,

energy reserves for fat

• Muscle – Movement and force

application

• Nervous– Stimulates action

potential to activate body functions

Ectoderm – Nervous system and the epidermis of skin

Mesoderm – Connective tissue, blood, muscles

Endoderm – GI tract, Bladder, and Respiratory tract

1. Covering and Lining 2. Glandular

Epithelium

Functions:

Protection, Filtration, Secretion, Absorption, and Excretion

Divisions:

Exposed to body cavity

Attachment between Epithelial and Connective Tissue

Avascular – NO blood vessels

Cell Junctions – Point of contact between adjacent membranes of various cell types

1. Tight Junctions – Fluid tight seal between cells to prevent leaking of substances into blood or surrounding tissues; stomach lining & urinary bladder, and intestines

2. Anchoring Junction (Desmosomes) – Fasten cells to on another, common in stretched areas such as heart, uterus, and outer skin

3. Gap Junction – Allow passage of chemical/electrical signals through connexons (protein tunnels) from cell to cell; i.e. muscular contraction, pain

Tissue Arrangements

Cell Shapes

Simple Squamous• Function: Filtration, diffusion, osmosis, and

secretion in serous membranes • Location: Kidneys Glomeruli (water, glucose,

and wastes), Air Sac of Lungs (Gas Exchange), Heart and Blood Vessels (Nutrients & Medicine)

Simple Cuboidal• Function: Secretion and Absorption

• Location: Kidney Tubules (Wastes), Ovary Surface (Ova)

Ciliated Simple Columnar• Function: Moves fluids and particles along

passageways• Location: Found in respiratory tract (mucosal

Movement), fallopian tubes (Ova movement), sinuses (Pathogen removal Runny Nose)

Cilia

Non-Ciliated Columnar• Function: Microvilli secretion and Absorption

• Location: GI tract lining (Absorption of nutrients and water) & Gallbladder (Secretion of Bile)

Pseudostratified Columnar Epithelium

• Functions: Mucus movement by cilia action• Location: Found in upper respiratory tract and

urethra, and gonads of males (Sperm maturation)

Stratified Squamous• Functions: Protection of superficial layers of skin;

vagina, mouth, esophagus, tongue• Location:

– Keratinized = Superficial Layers of Skin– Non-Keratinized = Wet Surfaces (Mouth, Vagina,

Tongue)

Stratified Cuboidal• Functions: Protection and limited secretion of sweat glands

• Location: Sudoriferous Glands (SWEAT)

Stratified Columnar

Transitional Epithelium• Function: Accommodate Distension in the urinary

tract and vaginal walls as fluid pressures vary.– Stretched = Squamous Relaxed = Cuboidal  

• Location: Lining of the ureters, urethra, and bladder

Glandular Epithelium: Endocrine

• Function: Produce hormones • Location: Thyroid, Pituitary Gland, Ovaries,Testicles

Secretion of exocrine glands – Merocrine (or eccrine) secretion

• Forms the product and discharge from the cell entirely– Salivary Glands

– Apocrine secretion• Product forms at apical surface and pinches off from rest of cell

– Mammary gland – Holocrine secretion

• Accumulates secretory product in cytosol, cell dies and is discharge with its product– Sebaceous Gland (Acne)