1. Kharkov National Medical University Department of Histology, Cytology and Embryology Lecture 1. Introduction. Cytology

2. Histology – is the science that studies microscopic structure and function of the human organism, the organization of the tissues and organs. Cytology – is the science that study the structure and functions of the cell. Embryology – is the science that research embryonic development (formation) of human body

3. Cytology

4. The cell is: - the smallest structural and functional unit, - the smallest structural and functional unit, - the elementary level of organization of the multicellular organisms. - the elementary level of organization of the multicellular organisms. - a self-regulating, self-regenerating and self-governing biological system cell possesses all features of the whole organism, such as metabolism, growth, irritability, movement, and others. cell possesses all features of the whole organism, such as metabolism, growth, irritability, movement, and others.

5. Types of cells in human body

6. Cells produce matrix:

7. Cells form tissues, Tissues form organs and systems Cells form tissues, Tissues form organs and systems

8. Methods of investigation

9. Microscopy – basic method Light source Light source Condenser lens Condenser lens Stage Stage Objective lens Objective lens Ocular lens Ocular lens *** ***

10. Electron microscopy

11. Ultrastructure of cells and intercellular matrix (organelles) Ultrastructure of cells and intercellular matrix (organelles) May be: Transmission E M Transmission E M Scanning E M Scanning E M

12. Another methods: Polarized microscopy (property of tissues: can rotate the angle of the plan of polarized light) Polarized microscopy (property of tissues: can rotate the angle of the plan of polarized light) Faso-contrast microscopy Faso-contrast microscopy

13. Light and electron microscopy - are 2 mane methods in histology

14. Levels of biological systems Biomolecules Biomolecules membranes organelles membranes organelles CELL CELL

15. Membrane contents: 1 – lipids (hydrophilic head) 1 – lipids (hydrophilic head) 2 – lipids (hydrophobic tails) 2 – lipids (hydrophobic tails) 3 – proteins 3 – proteins 4 – carbohydrates (only outer cell membrane) 4 – carbohydrates (only outer cell membrane)

16. Lipids may be: Phospholipids – triglycerides (polar) Phospholipids – triglycerides (polar) Cholesterol (non-polar) Cholesterol (non-polar)

17. Phospholipids : Phosphate group (hydrophilic heads) Phosphate group (hydrophilic heads) Glycerol Glycerol Fatty acids (hydrophobic tails) Fatty acids (hydrophobic tails)

18. Cholesterol is especially abundant in the plasma membrane of mammalian. Cholesterol is especially abundant in the plasma membrane of mammalian. As much as 30 to 50 percent of the lipids in plant plasma membranes consists of cholesterol As much as 30 to 50 percent of the lipids in plant plasma membranes consists of cholesterol

19. Proteins may constitute close to 50% of membrane content function : in the membranes 1- channels, 1- channels, 2- pumps, 2- pumps, 3- receptors, 3- receptors, 4- enzymes, 4- enzymes, 5- integrative, 5- integrative, 6- structural 6- structural

20. Carbohydrates (in glycoproteins) Present in the outer cell membrane Present in the outer cell membrane Role - Receptors Role - Receptors

21. Outer cell membrane – cytolemma or plasmalemma

22. Membranes form BARRIER between 2 mediums, Membranes form BARRIER between 2 mediums, regulate exchange and trasport regulate exchange and trasport creates COMPARTMENTS creates COMPARTMENTS in the cell in the cell

23. Membranes form: Outer cell membrane – cytolemma or plasmalemma Outer cell membrane – cytolemma or plasmalemma Organelles Organelles Vesicles Vesicles Nucleus - nuclear envelop Nucleus - nuclear envelop

24. Structure of a typical cell 1. Cell membrane 2. Nucleus 3. Cytoplasm inclusions organelles Cytosol = matryx, hialoplasm

25. NOTE Cell consists of: Cell consists of: - Outer cell membrane, - Outer cell membrane, - Cytoplasm and - Cytoplasm and - Nucleus - Nucleus

26. Outer cell membrane – cytolemma or plasmalemma

27. Cell junction - consist of multiprotein complexes that provide contact between neighbouring cells or between a cell and the extracellular matrix. - consist of multiprotein complexes that provide contact between neighbouring cells or between a cell and the extracellular matrix.

28. 12 G Where Cells contact -- Cell junction

29. Cell junction Communicating or Gap junctions junction Communicating or Gap junctions junction Tight junction Tight junction Desmosomes Desmosomes

30. Tight junction present in different types of epithelia present in different types of epithelia two layers of glycocalyx are fused. two layers of glycocalyx are fused. act as a barrier, that prevents the movement of molecules into the intercellular spaces act as a barrier, that prevents the movement of molecules into the intercellular spaces

32. G

33. Gap junction allow for direct chemical communication between adjacent cellular cytoplasm through diffusion without contact of the extracellular fluid allow for direct chemical communication between adjacent cellular cytoplasm through diffusion without contact of the extracellular fluid numerous in muscle tissue numerous in muscle tissue

34. Gap junction Consists of six connexin proteins, interacting to form a cylinder with a pore in the centre - connexon. Consists of six connexin proteins, interacting to form a cylinder with a pore in the centre - connexon. This protrudes across the cell membrane, and when two adjacent cell connexons interact, they form the gap junction channel This protrudes across the cell membrane, and when two adjacent cell connexons interact, they form the gap junction channel

35. Desmosome - is the most common type of junction is the most common type of junction Provides cell attachment Provides cell attachment

36. dense layer of protein present on the inner (cytoplasmic) surface the cell membrane (= dense plaque). dense layer of protein present on the inner (cytoplasmic) surface the cell membrane (= dense plaque). Intermediate filaments composed of keratin or desmin are attached to dense plaque Intermediate filaments composed of keratin or desmin are attached to dense plaque small gap between two membranes is rich in glycoprotein Cadherin, which looks like a thin filaments. small gap between two membranes is rich in glycoprotein Cadherin, which looks like a thin filaments.

37. Inside the cell : Cytoplasm and nucleus Cytoplasm and nucleus

38. Inside the cell … Cytoplasm consists of: Matrix (hialoplasm, cytozol) Matrix (hialoplasm, cytozol) Organelles Organelles Inclusions Inclusions

39. Inclusions Inclusions are "nonliving" components of the cell. Inclusions are "nonliving" components of the cell. They include granules with secretions, pigment granules, lipid droplets, and glycogen. They include granules with secretions, pigment granules, lipid droplets, and glycogen.

40. Organelles: classification by structure Membranous or Membranous or"membrane-bound" Non-membranous Non-membranous

41. Organelles: classification by function General (present in every cell, perform general function) General (present in every cell, perform general function) Special (in specialised cell, perform special function) Special (in specialised cell, perform special function)

42. Rough (rough-surfaced) endoplasmic reticulum is a membranous network of sac-like structures cisternae. is a membranous network of sac-like structures cisternae. the cisternal space (or lumen) is continuous with the perinuclear space but separate from the cytosol. the cisternal space (or lumen) is continuous with the perinuclear space but separate from the cytosol.

43. The surface of the RER is studded with ribosomes giving it a "rough" appearance (hence its name). The surface of the RER is studded with ribosomes giving it a "rough" appearance (hence its name). Function - synthesis of proteins Function - synthesis of proteins

46. Smooth(-surfaced) endoplasmic reticulum, SER

47. SER consists of tubules that are located near the cell periphery. SER consists of tubules that are located near the cell periphery.Function: It synthesizes lipids - phospholipids and steroids. It synthesizes lipids - phospholipids and steroids. It also carries out the metabolism of carbohydrates (synthesis of glycogen, gluconeogenesis ), It also carries out the metabolism of carbohydrates (synthesis of glycogen, gluconeogenesis ), drug detoxification, and steroid metabolism. drug detoxification, and steroid metabolism. Storage of Ca-ions (only in muscle cell) Storage of Ca-ions (only in muscle cell)

48. Golgi apparatus also known as the Golgi complex, Golgi body, or simply the Golgi, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. is an organelle found in most eukaryotic cells. It was identified in 1897 by the Italian physician Camillo Golgi and named after him in 1898. It was identified in 1897 by the Italian physician Camillo Golgi and named after him in 1898. Loks as a pack of sacs. Loks as a pack of sacs.

49. Golgi apparatus Golgi complex is connected with endoplasmic reticulum Golgi complex is connected with endoplasmic reticulum

50. Golgi apparatus Functions. 1. synthesis of substances, 1. synthesis of substances, which has begun in endoplasmic reticulum and is accomplished in the Golgi complex.

51. Golgi apparatus Functions. 2. formation of compound molecules – glycoproteins, lipoproteins. 2. formation of compound molecules – glycoproteins, lipoproteins.

52. Golgi apparatus Functions. 3. production of lysosomes and secretory vesicles. 3. production of lysosomes and secretory vesicles.

53. Mitochondrion is a membrane- enclosed organelle found in most eukaryotic cells. is a membrane- enclosed organelle found in most eukaryotic cells.

54. Mitochondrion A mitochondrion contains outer and inner membranes composed of phospholipid bilayers and proteins. A mitochondrion contains outer and inner membranes composed of phospholipid bilayers and proteins. Folds of inner membrane – cristae Folds of inner membrane – cristae Inside M. lie matryx Inside M. lie matryx

55. Mitochondrion Mitochondria provide energy for various cellular functions, Mitochondria provide energy for various cellular functions, Produce ATP molecules Produce ATP molecules by Krebs cycle by Krebs cycle

56. Mitochondrion

57. FA

58. Lysosome Lysosomes are round vesicles that contain acid hydrolase enzymes that break down waste materials and cellular debris. Lysosomes are round vesicles that contain acid hydrolase enzymes that break down waste materials and cellular debris. Lysosomal enzymes help in digesting the materials within phagosomes. They can be described as the stomach of the cell. Lysosomal enzymes help in digesting the materials within phagosomes. They can be described as the stomach of the cell.

59. Lysosome Cycle lysosomes are formed from Golgi complex lysosomes are formed from Golgi complex The nearly produced lysosome is primary lysosome The nearly produced lysosome is primary lysosome

60. Lysosome Cycle primary lysosome fuses with the phagosome -- secondary lysosome or phagolysosome primary lysosome fuses with the phagosome -- secondary lysosome or phagolysosome part of undigesting material may remain within the cell as residual bodies. part of undigesting material may remain within the cell as residual bodies.

62. Fagocytosis

63. Non-membranous organelles: Microfilaments Microfilaments Microtubules Microtubules Centrioles (Cell Center) Centrioles (Cell Center) Ribosomes Ribosomes

65. The cytoskeleton - is made up of three kinds of protein filaments: - is made up of three kinds of protein filaments: Actin filaments (also called microfilaments) Actin filaments (also called microfilaments) Intermediate filaments Intermediate filaments Microtubules Microtubules

66. Microfilaments, Microtubules form “Skeleton” of the cell

67. Β-tubulin actin

68. Cell center Centriole = 9 x 3 microtubules; 2 centrioles = cell center = Β-tubulin = Β-tubulin (mitosis, meiosis), flagella, basal bodies and cilia function -formation of mitotic spindle (mitosis, meiosis), flagella, basal bodies and cilia

71. Cell center

72. Special organelles Myofibrils Myofibrils Cilia, microvilli Cilia, microvilli

73. Nucleus Eukaryotes have nucleus Eukaryotes have nucleus

74. Nucleus is a membrane-limited structure: Nucleolemma - nuclear envelope Nucleolemma - nuclear envelope Nucleoplasm Nucleoplasm Nucleolus Nucleolus Chromatin, chromosomes Chromatin, chromosomes

75. Nuclear envelope - Consists of two membranes. - Consists of two membranes. The outer layer is continuous with endoplasmic reticulum. The outer layer is continuous with endoplasmic reticulum. The inner layer provides attachment to the ends of the chromosomes. The inner layer provides attachment to the ends of the chromosomes.

76. Nuclear envelope There are gaps, called nuclear pores There are gaps, called nuclear pores The nuclear pore transports some substances from nucleus into cytoplasm The nuclear pore transports some substances from nucleus into cytoplasm

77. Nuclear pore structure

78. Nucleolus Nucleolus is the site very amplificated molecule of DNA. Nucleolus is the site very amplificated molecule of DNA. It is the site of active synthesis of ribosomal RNA. It is the site of active synthesis of ribosomal RNA.

79. Nucleolus Nucleolus is the site very amplificated molecule of DNA. Nucleolus is the site very amplificated molecule of DNA. It is the site of active synthesis of ribosomal RNA. It is the site of active synthesis of ribosomal RNA.

80. In the nucleolus RNA binds with protein and forms ribosomal subunits, which leave the nucleus via nuclear pores to the cytoplasm as ribosomes. In the nucleolus RNA binds with protein and forms ribosomal subunits, which leave the nucleus via nuclear pores to the cytoplasm as ribosomes.

81. Chromosome - DNA molecules which contain genetic information DNA molecule is coiled around the histone core, which consists of eight gistone molecules. DNA molecule is coiled around the histone core, which consists of eight gistone molecules. Such particles, consisting of gistone core and DNA, are called nucleosomes. Such particles, consisting of gistone core and DNA, are called nucleosomes.

82. Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell. is the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are 1) to package DNA into a smaller volume to fit in the cell, 2) to strengthen the DNA to allow mitosis, 3) to prevent DNA damage, and 4) to control gene expression and DNA replication The primary functions of chromatin are 1) to package DNA into a smaller volume to fit in the cell, 2) to strengthen the DNA to allow mitosis, 3) to prevent DNA damage, and 4) to control gene expression and DNA replication

83. Sites where chromatin fibrils are packed very tightly together are heterochromatin sites – non-active. Sites where chromatin fibrils are packed very tightly together are heterochromatin sites – non-active. there are less condensed chromatin fibrils loops - euchromatin sites - active. there are less condensed chromatin fibrils loops - euchromatin sites - active.

84. Euchromatin predominates in metabolically active nuclei, Euchromatin predominates in metabolically active nuclei, Heterochromatin predominates in metabolically inactive nuclei Heterochromatin predominates in metabolically inactive nuclei

85. Euchromatin predominates in metabolically active nuclei, that are called open-faced nuclei. Euchromatin predominates in metabolically active nuclei, that are called open-faced nuclei. Heterochromatin predominates in metabolically inactive nuclei, that are called closed-faced nuclei Heterochromatin predominates in metabolically inactive nuclei, that are called closed-faced nuclei

86. Chromosome is an organized structure of DNA and protein found in cells.

88. Cell Cycle The life of a somatic cell is a cyclic process The life of a somatic cell is a cyclic process It is called cell cycles It is called cell cycles consists of two periods: interphase and mitosis. consists of two periods: interphase and mitosis.

89. Interphase Interphase is a period between two divisions of the cell. Consists of 3 phases - G 1, S, G 2

90. In G1 phase: cell grows, performs its routine functions. cell grows, performs its routine functions.

91. In G 1 phase Nondividing cells complete period G 1 by growing old and death of the cell Nondividing cells complete period G 1 by growing old and death of the cell Dividing cell – prepare for next phase Dividing cell – prepare for next phase

92. S- phase = synthesis phase DNA molecules are duplicated DNA molecules are duplicated each chromosome now consists of two DNA molecules or two chromatids. At the beginning of this phase, the chromosome number is 2N and at the end, the chromosome number is 4N. each chromosome now consists of two DNA molecules or two chromatids. At the beginning of this phase, the chromosome number is 2N and at the end, the chromosome number is 4N.

93. G 2 phase In this phase synthesis of proteins, which are required for cell division, takes place. In this phase synthesis of proteins, which are required for cell division, takes place. After phase G 2 mitosis always begins After phase G 2 mitosis always begins

94. G 0 phase cell can leave the cycle in any phase, except G 2, and enter to so-called G 0 phase (outside the cycle). The cell that leaves the cycle is considered as reserve stem cell. cell can leave the cycle in any phase, except G 2, and enter to so-called G 0 phase (outside the cycle). The cell that leaves the cycle is considered as reserve stem cell.

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

96. Prophase Chromosomes becomes more and more coiled become recognisable. Chromosomes becomes more and more coiled become recognisable. the nuclear membrane breaks down and the nucleoli disappear the nuclear membrane breaks down and the nucleoli disappear

97. Two centrioles separate and move to opposite poles of the cell. Two centrioles separate and move to opposite poles of the cell. Сentrioles produce a number of microtubules which pass from one centriole to other and form a spindle of division. Сentrioles produce a number of microtubules which pass from one centriole to other and form a spindle of division.

98. Metaphase - chromosomes move to a position midway between the two centrioles at the equator of the cell and form the equatorial plate - chromosomes move to a position midway between the two centrioles at the equator of the cell and form the equatorial plate

99. anaphase - the chromatids separate and move to opposite poles of the cell - the chromatids separate and move to opposite poles of the cell At the end of anaphase chromatids are called chromosomes. At the end of anaphase chromatids are called chromosomes.

100. Telophase - two daughter nuclei are formed by appearance of nuclear membranes around them. - two daughter nuclei are formed by appearance of nuclear membranes around them. The chromosomes gradually elongate and become indistinct. The chromosomes gradually elongate and become indistinct. Nucleoli reappear. Nucleoli reappear.