Histopath

Histology- microscopic study of normal tissue Biopsy- removal of tissues for diagnostic purposes

- acting as barrier (skin) - permitting A. Covering Epithelia

Autopsy- examination of organ of a dead body to determine cause of death

- Blood vessel are absent

Embryonic tissue- a fertilized egg divides and form smaller cells

- some epithelia are specialized for the reception of stimuli

-

after morphogenetic movements, these cells becomes arranged in 3 germ layers: 1. ECTODERM- inner layer - forms linings of digestive tract and derivatives 2. ENDODERM- middle layer - Forms tissues such as muscle, bone, blood vessel 3. MESODERM- outer - Forms skin and neuro ectoderm Tissues- group of cell of common origin and common function 4 Categories of tissues: 1. Epithelial tissue- derived from all 3 germ layer 2. Connective- mesoderm 3. Muscle- mesoderm 4. Nervous- ectoderm Pathology- study of abnormal tissue Epithelial Tissue a. Covering epithelia b. Glandular General Functions - protecting underlying structures (epithelium lining the mouth)

- exposed to physical injury and infections

CLASSIFICATIONS 1. Accordingly to cellular arrangement a. Simple- one-cell thick b. Pseudostratified- appear to be more than one-cell thick but actually cells rest on common basement membrane. c. Stratified- many layers of cells II- CELL SHAPE A. Squamous- flattened cells (naving stones) B. Cuboidal- cube like (isodiametric) C. Columnar-cells that are taller than they are wide D. Transitional- cells that change their shape when the epithelium is stretched (ex. Gall bladder) Simple 1. 2. -

Squamous Bowman’s capsule Endothelium of blood vessels Loop of henle Alveoli of lungs Cuboidal Walls of thyroid follicles A duct of glands

3. Columnar - Gall bladder (non-ciliated) - Uterine tube (ciliated) (propulsion of mucus/ egg cells) Stratified 1. Squamous - ( Keratinized ) ex. Epidermis of the skin - ( Non- Keratinized ) ex. Vagina, Esophagus, Cervix 2. Cuboidal - Ex. Sweat gland duct 3. Columnar - Ex. Male urethra 4. Transitional - Ex. Urinary tract Pseudostratified 1. Columnar - ( Non- Ciliated ) ex. female reproductive tract - ( Ciliated ) ex. Trachea Glandular 1. Exocrine- glands with ducts a. Tubular- stomach, uterus b. Acinar/Alveolar- pancreas, salivary gland c. Tubule-acinar- prostrate 2. Endocrine - Ductless - Excrete hormones (blood) - Highly vascular and discharge their secretion into blood vessel Method of Secretion 1. Merocrine - No loss of cytoplasm - Secretion accumulate below the free surface of the cell through which it is released - Ex. Goblet cells, sweat glands 2. Apocrine

-

With cytoplasmic loss Secretion accumulate below the free surface but can only released by breaking away of the distal port of the epithelium - Ex. Mammary glands in milk secretion 3. Holocrine - Complete breakdown of secretory cells - Ex. Sebaceous glands Connective tissue -

-

Cells that are usually widely separated by a large amount of intercellular substances Blood, blood forming tissues, bone and cartilage are member of the group

Characteristics -

mesenchyme as their common tissue of origin ( mesenchyme derived from mesoderm) - varying degrees of vascularity - non-living extracellular matrix, consisting of ground substance and fibers - cells are not as abundant nor as tighly packed together as in epithelium I. General CT - Loose - Dense II. Special CT - Cartilage- hematopoietic  Hyaline- coastal cartilage, trachea  Fibrous- interverlebral discs  Elastic- external ear - Bone - Blood - Lymph node III.

Loose CT Common examples include:

-

 Mucoid tissue Dermis Capsules of organ Tendons Stroma of cornea

-

Increased tendency for bone break  Rate of blood cells synthesis declines in the elderly  Injuries don’t heal as rapidly

Bone   -

Cancellous/ Spongy Epiphysis or end of long bone Compact Diaphysis or shaft is chiefly compact bone

Hematopoietic  Myeloid- BM  Lymphoid- Spleen Muscle tissues 1. Smooth (involuntary) - Found in intestinal tract and blood vessels 2. Striated (voluntary) - Found in skeletal muscles 3. Cardiac ( striated but involuntary) - Heart