Histology and Embryology
Zhong jie Li （李仲杰）
School of medicine, Zhejiang University
lizhongjie@zju.edu.cn
Chapter 1
Introduction
Relationship:
cell --- tissue---organ---system---human body
Key points:
I.
What’s histology?
II. Why we study it ?
III. How to study it ?
---Histological methods.
I. What’s histology?
Histology (Greek words):
/histo---tissue
/logia---study of ,or knowledge of
Histology means the knowledge of tissue, is a
branch of Anatomy.
Anatomy:
---gross anatomy
---microscopic anatomy/microanatomy
Histology :
a science which study the microstructure and
the relationship between the structure and
function of human being.
Cell: smallest unit of structure and function of body
Tissue: group of cell and extracellular matrix
Four basic tissue:
---Epithelial tissue
---Connective tissue
---Muscular tissue
---Nervous tissue
Organ: made up of tissue, have special shape,
structure and function
--- the cavity organ
histology
--- parenchymatous organ
anatomy
System:
organs which have related function get together.
What’s Embryology?
Embryology is a kind of science
which study the processes and the
regulations of the development of
human fetus.
--- Preembryonic period
--- Embryonic period
(8 weeks before)
--- Fetal period (9-38 weeks)
II.
Why medical
students should
study Histology
?
Graduate
Intern (exercitation)
Clinic (Medicine,Surgery,Gynecology, Pedology,
Pathphysiology
Physiology
Pharmocology
etc.)
Basic medicine &Surgery
BiochemistryParasitology Patholo
gy
Histology & Embryology
Microbiology
Immunology
Anatomy
III.
How to study it
• Microscopy:
Light microscopy (LM)
Electron microscopy (EM)
• Transmission electron microscope (TEM)
• Scanning electron microscope (SEM)
• Staining:
H&E
Histochemistry
Immunohistochemistry
In situ hybridiztion …
Relative Sizes in Histology
Standard Units of Measure
Light Microscopy
:The resolution of the human
eye is 0.2 mm.
:The resolution of the light
microscope is 0.2 um.
:
The resolution of the light
microscope is 0.2 nm.
Preparation of tissue for LM
The most routine one is paraffin section stained
with hematoxylin and eosin(H&E)
The steps:
a. Obtaining the specimen: fresh, small pieces
tissue block( less than 5mm3)
b. Fixation: fixatives: use formalin or Bouin’s to
preserve structural organization
c. Dehydration: use ethyl alcohol to get rid of
water of tissue and cell
d. Clearing: use xylene to
get rid of alcohol
*alcohol and xylene are
embedding mediums
e. Embedding: firstly, heat
the paraffin, make it melt,
then put tissue block into
melted paraffin, allow
paraffin harden, the
tissue block is embedded
in.
f.
Sectioning: use microtome to cut the tissue
into 3-8um thick sections, then mounted
them on glass slides
g. Staining
H&E --- Routine staining for LM
---Hematoxylin: basic dye, combines with acidic components, make
them appear blue colour- basophilic, i.e. cell nucleus, hyaline
cartilage
---Eosin: acidic dye, combines with basic components, make them
appear pink colour- acidophilic (eosinophilic), i.e. cytoplasm
nucleolus
• basophilic
• acidophilic (eosinopilic)
• neutrophilc
nucleus
H&E staining
TEM:
transmission electron microscopy
The resolution of the TEM is about
0.1-0.5nm.
Basophilic granulocyte
(TEM)
Basophilic granulocyte
(LM)
SEM:
scanning electron microscopy
The resolution of SEM is about 5nm.
Histochemistry & Cytochemistry
To combine histological and cytological methods
with chemical and biochemical methods and reveal
the chemical composition of tissue and cell in situ.
Periodic acid-Schiff (PAS) reaction
Localize polysaccharides, such as glycogen, in tissues and
cells.
PAS+
Produce an insoluble magenta complex
Immnohistochemistry
 To use labelled antibodies as specific reagents
for localizing tissue and cell constituents
(antigens) in situ
 Observation:Fluorescence microscope
In Situ Hybridization
• A method for detection of specific RNA or
DNA sequences directly in cells or tissue
sections
• incubate tissues with probe to detect cells
expressing gene
Methods of learning:
---Must think in 3 dimensions
---Structure and function
---part and whole.
oblique section
Horizontal section
longitudinal section
Structure and function
Part and whole
舒张状态
收缩状态
Reference books
• 1. Jun min T, Ji cheng L. Textbook of Histology and Embryology.
Peking University Medical Press, 2011
• 2. William k. Ovalle & Patrick C. Nahirney. Netter’s essential
histology, Elsevier Health Sciences,2007
• 3. Gaetner MP, Hlatt JL. Colour Textbook of Histology. Williams &
Wilkins, 1997
Course web:
http:/m-learning.zju.edu.cn
(2015 Histology and Embryology)
The composition of final score:
1. Lecture and Lab attendence: 10 %
2. Quiz: 15% （each quiz 5%）
3. Lab test: 25%
4. Final written examination：50%
Histology： 35-40%
Embryology：10-15%
*. If you want to pass this course, final written
examination score must be more than 50.
Preparation of laboratory work
Have the tools ready:
1) Pencils (red-blue pencil)
2) rubber, ruler and so on