Cheatography
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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 |
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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 |
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Four Broad Categories of Tissues
1. Epithelial Tissue |
2.Connective Tissue |
3. Nervous Tissue |
4. Muscular 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 |
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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) |
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(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 |
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