1. Kharkov National Medical University
Department of
Histology, cytology and embryology

2. studies microscopic structure and function of the human organism
HISTOLOGY
studies microscopic structure and function of the human organism

3. The Cell

4. The Cell
is the structural and functional unit
of the organism

5. Structure of a typical cell
Cell membrane
Nucleus
Cytoplasm
non-membranous organelles
cytosol
membranous organelles

6. structural unit of a cell
Biological
Membrane is a
structural unit of a cell
Biological
membrane
in the
cell membrane,
nucleus
and some
organelles

7. Cell membrane (plasmalemma). Outer is glycocalyx
Membrane permeability covered in physiology

8. Non-membranous Organelles
1. Cytoskeleton
is the system of microtubules

9. 2. Cell center 2 centrioles – consist of 9 triplets of microtubules.
Formation of mitotic spindle

10. 3. Ribosomes two subunits - synthesize proteins; Fixed on RER,
or free ribosomes

11. Membranous Organelles

12. 1. Mitochondrion (two membranes) - synthesis of energy - ATP

13. 2. Endoplasmic reticulum (net of membranes) smooth (SER) & rough (RER)
RER contains ribosomes
SER
Function: Synthesis  Storage  Transport
SER of lipids and carbohydrates
RER of proteins

14. 3. Golgi Apparatus Packaging of proteins, formation of lysosomes,
secretion,
3. Golgi Apparatus
formation of compound molecules – glycoproteins, lipoproteins

15. 4. Lysosome is digestive apparatus, contains enzymes (autolysis)

16. Intercellular Junctions
1) Gap Junction
has channel proteins

17. 2) Tight Junctions
Interlocking proteins

18. 3) Desmosomes
STRONG BOND
Found in superficial layers of skin

19. INCLUSIONS are nonliving components of a cell like:
secretory granules,
pigment,
lipid,
glycogen

20. Nucleus – contains genetic information

21. Cell Cycle The life of a somatic cell is a cyclic process - cell cycle
consists of two periods: interphase and mitosis.
interphase contains G 1, S, G 2 stages

22. G1 CELL CYCLE: Stages S G2 M Go G1 Gap 1 growth, function
DNA Synthesis
(for new
cells)
stem or
for differentiation
Gap 2
formation
of m.spindle,
energy
Mitosis
Gap 1 for a new cycle

23. Mitosis Mitosis is the process of somatic cells division.
Mitosis consists of :
prophase, metaphase,
anaphase, telophase.

24. Prophase Ch Chromosomes become more coiled and visible
the nuclear membrane breaks down
Microtubules of centrioles form a spindle of division. Ch

25. Metaphase
- chromosomes move to the center of the cell and form the equatorial plate Ch

26. Anaphase Ch
- the chromosomes separate and move to opposite poles of the cell

27. Telophase - two daughter nuclei are formed.
the chromosomes uncoiledand become indistinct.

28. IS FORMATION OF THE HUMAN ORGANISM
EMBRYOGENESIS
IS FORMATION OF THE HUMAN ORGANISM

29. Week 1
1.Fertilization – is the fusion of the sperm and ovum = Zygote formation
2.Cleavage – is the division of the zygote in the uterine tube = Blastula formation

30. . Week 1 uterus uterine tube 3-5 cells stage Cleavage Morula
Blastula . .
uterus
uterine tube
Implantation
Day 6 - 8
zygote
Fertilization

31. At the end of cleavage outer cells (trophoblast) involve nutritive fluid, which forms cavity, moving inner cells (embryoblast). Blastula is formed.
Inner Cell Mass
(embryoblast)
Trophoblast

32. Week 2. 3. Early Gastrulation (division and. movement of cells)
Week 2. 3.Early Gastrulation (division and movement of cells). At the beginning of gastrulation (6,7 day) germ sinks into the uterine wall – implantation. Gastrulation leads to formation of three germ layers – ectoderm, endoderm and mesoderm and extraembryonic organs: amnion, yolk sac chorion

33. Week 2 chorion Extraembryonic Mesoderm of Amnion and Yolk Sac Ectoderm
Endoderm
yolk
sac

34. Gastrulation is finished with the formation of axial organs – neural tube, notochord, somites (mesoderm), locating between ectoderm and endoderm. From them develop tissues and organs!
Neural tube
Somate
amnion
ectoderm
endoderm
yolk
sac
Notochord

35. 4. Body flexion (amnion increases and forms body)

36. Body flexion formation (Gut formation
Body flexion formation (Gut formation. Gut is the upper part of yolk sac) longitudinally transversely
gut
head
right
left

37. Differentiation of germ layers and axial organs
What develops from them?

38. Surface Ectoderm differentiates to skin, oral, rectal epithelium, corneal epithelium, tooth enamel
amnion ectoderm
stomatodeum

39. Endoderm differentiates to epithelium of stomach, intestine, liver, pancreas, respiratory, endocrine system weeks - gut
endoderm gut

40. Extra mesoderm- formation of the first blood vessels in the wall of yolk sac and allantois

41. Body Mesoderm dermatome - dermis of skin myotome - muscles, 1. Somite
sclerotome - skeleton, except skull,
1. Somite
urogenital system
including kedneys, gonads,
ducts, and accessory glands
3. Intermediate Mesoderm.
Nephrotome
2. Lateral Mesoderm -
serous membranes of pleura, pericardium and peritoneum
4. Mesenchyme (loose part) –
connective tissue of viscera and limbs, blood and lymph cells, vessels,
smooth muscle

42. Late embryonic stages
Histogenesis
Organogenesis

43. The End