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A&P Chapter 5 Histology Cheat Sheet (DRAFT) by

Histology, microscopic anatomy, tissue, cells, mitosis

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Terms

Histology
(micro­scopic anatomy)—the study of tissues and how they are arranged into organs
Tissue
a group of similar cells and cell products that arise from the same region of the embryo and work together to perform a specific structural or physio­logical role in an organ
-First tissues appear when these cells start to organize themselves into layers; First two, and then three strata
Organ
structure with discrete boundaries that is composed of two or more tissue types

Three primary germ layers

Ectoderm (outer)
Gives rise to epidermis and nervous system
Endoderm (inner)
Gives rise to mucous membrane lining digestive and respir­atory tracts, digestive glands, among other things
Mesoderm (middle)
becomes gelatinous tissue called mesenchyme - Wispy collagen fibers and fibrob­lasts in gel matrix, Gives rise to muscle, bone, blood

Conn­ective Tissue: Overview

Connective tissue—
a type of tissue in which cells usually occupy less space than the extrac­ellular material
 
Binding of organs—
tendons and ligaments
Support—
bones and cartilage
Physical protec­tion—
cranium, ribs, sternum
Immune protec­tion—
white blood cells attack foreign invaders
Movement
bones provide lever system
Storage—
fat, calcium, phosphorus
Heat produc­tion—
metabolism of brown fat in infants
Transport—
blood
 

Four Broad Categories of Tissues

1. Epithelial Tissue
2.Conn­ective Tissue
3. Nervous Tissue
4. Muscular Tissue

Epithelial Tissue

Epit­helial Tissue

Covers body surface and lines body cavities
• Basement membrane—layer between an epithelium and the underlying connective tissue
• Collagen
• Anchors the epithelium to the connective tissue below it
• Basal surface—surface of an epithelial cell that faces the basement membrane
• Apical surface—surface of an epithelial cell that faces away from the basement membrane

Cells Found in Connective Tissue

Macrop­hages- phagoc­ytize foreign material and activate immune system when they sense foreign matter (antigen)
-Arise from white blood cells called monocytes
Leukocytes, or white blood cells
-Neutro­phils wander about attacking bacteria
-Lympho­cytes react against bacteria, toxins, and other foreign material
Plasma cells synthesize diseas­e-f­ighting antibodies
-Arise from lympho­cytes
Mast cells are found alongside blood vessels
-Secrete heparin to inhibit clotting
-Secrete histamine to dilate blood vessels

2 Types of Fibrous Connective Tissue

Loose connective tissue
– Much gel-like ground substance between cells
• 2 Types: Areolar & Reticular
Dense connective tissue
– Fibers fill spaces between cells
– Types vary in fiber orient­ation
• Dense regular connective tissue
• Dense irregular connective tissue
 

2 Main Types Epithelial Tissue

Simple epithelium
-Contains one layer of cells
-Named by shape of cells
-All cells touch the basement membrane
Stratified epithelium
-Contains more than one layer
-Named by shape of apical cells
-Some cells rest on top of others
-does not touch basement
-membrane
-Deepest layers undergo continuous mitosis
-Their daughter cells push toward the surface and become flatter as they migrate farther upward
-Finally die and flake off—ex­fol­iation or desqua­mation

Four types of simple epithelia

• Three named for their cell shapes
– Simple squamous (thin, scaly cells)
– Simple cuboidal (square or round cells)
– Simple columnar (tall, narrow cells)
 
(4)– Pseudo­str­atified columnar
– Not all cells reach the free surface
– Shorter cells are covered over by taller ones
– Looks stratified
– Every cell reaches the basement membrane
Goblet Cells
winegl­ass­-shaped mucus-­sec­reting cells in simple columnar and pseudo­str­atified epithelia=

Two Kinds of Stratified Squamous Epithe­lia

Kerati­nized
found on skin surface, abrasion resistant Multiple cell layers with cells becoming flat and scaly toward surface keratin is a tough protein
• Epidermis; palms and soles heavily kerati­nized
• Resists abrasion; retards water loss through skin; resists penetr­ation by pathogenic organisms
Nonker­ati­nized
lacks surface layer of dead cells