Histology- 1-18-07

Front 1

Definitions:
- Histology-

- Tissues-

- Cells-

Back 1

histology- study of tissues and cell types

tissues- organized aggregation of cells that function in collective manner

cells- basic functional unit of body. Cells together function in the body (not usually on their own- gametes are the exception)

Front 2

Tissue components

Back 2

I. Cells

II. Extracellular Matrix- outside the cells, help convey signals. Produced by the cells

Front 3

Defining Tissues:
- Two definitional parameters

Back 3

1. Morphological- (what does it look like?). Separates epithelium and connective tissue

2. Functional- separates muscle and nerve tissue

Mixture used to define subclasses: (subdivided based on morphology in this case):
eg. Muscle- cardiac, smooth, skeletal
eg. Myoepithelium

Front 4

The Four Basic Tissues

Back 4

1. Epithelium
2. Connective Tissue
3. Muscle Tissue
4. Nerve Tissue

Front 5

I. Epithelial Tissue- General Features

Back 5

- always contiguous (connected)
- single (simple) or multi-layered (stratified) (refers to no. of cells that make up that tissue)
- cell-cell junctions create impermeable barrier
- subclasses based on shape and cell number
- General locations: free surfaces of body exterior; outer surface of internal organs; lining of body cavities, tubes and ducts; eg: pleural, pericardial, peritoneal

Front 6

II. Connective Tissue- General Features (underneath epithelial tissue)

Back 6

- cells separated from each other (not in direct contact)
- extracellular matrix (ECM) fills spaces (there's more ECM than cells)
- subclasses are based on cells and ECM
- Two major groups: loose CT (less compact), dense CT (more compact- ex: bone)

Front 7

III. Muscle- General Features

Back 7

- characterized by contractile proteins- actin and myosin
- cells are arranged in a particular fashion (along a particular axcess)
- Three main types:
1. smooth
2. skeletal
3. cardiac

Front 8

IV. Nerve Tissue- General Features

Back 8

- comprised on neurons and supporting cells (ex of supporting cells: glial cells)
- all exhibit electrical properties
- Neuron Anatomy:
1. cell body
2. two types of processes:
A.) Axon- single, efferent impulses (away)
B.) Dendrites- multiple, afferent impulses (to the cell)

Front 9

Teratomas

Back 9

- uncontrolled somatic cell that divides
- somatic cell differentiation in germ cells: ovarian= mostly benign; testis= all malignant

ex: Grey's Anatomy- teratomas can produce HcG