INTRODUCTION TO ANATOMY AND CELL BIOLOGY. THE CELL
1. Aims and scope of anatomy 2. Methods of morphological examination 3. Aims and scopes of cytology, histology and embryology 4. Methods for microscopic observations 5. The cell – basic structural and functional unit cellular organization and chemical composition cell membrane cell organelles – membranous and non-membranous Aims and scope of human anatomy
Anatomy – knowledge of the structure of living things Gr. ἀνατο ία anatomia = to cut apart; from ἀνατέ νειν ana: separate, apart from, and temnein , to cut up, cut open human anatomy animal anatomy (zootomy) plant anatomy (phytotomy) Human anatomy: Aim: how is the human body organized? structure of living organism spatial organization of living matter Scope (mission): why it is so organized? regularity of the structure functional approach Prof. Dr. Nikolai Lazarov 2 Major anatomical disciplines Systemic anatomy Topographical (regional) anatomy Plastic anatomy Clinical (applied) anatomy Dynamic anatomy (functional anatomy of the locomotor apparatus) Comparative anatomy the study of phylogenesis (Gr. φυλή/φ ῦλον, phyle/phylon = "tribe, race" + genesis, “ creation”, from Gr."gignesthai" = "to be born") Embryology the study of ontogeny, ontogenesis (ontos, present participle of “to be” + genesis, “creation”) Anthropology – the study of human behavior (Gr. ἄνθρωπος, anthrōpos = "human") Morphology – the study of the form or shape of an organism (Gr. morphe, “ form”) = anatomy + cytology + histology + embryology NB: Morpheus (Gr: Μορφέας, Μορφεύς, "he who forms, shapes, moulds", from the Greek morphe) is the Greek god of dreams and sleep Prof. Dr. Nikolai Lazarov 3 Systemic anatomy
Locomotor system (apparatus) – Osteology , scientific study of bones – Osteologia , Gr. os, ossis = bone Arthrology , study of articulations and ligaments – Arthrologia , Gr. arthros = joint Myology , specialized study of muscles – Myologia , Gr. myos = muscle Internal organs, viscera – Splanchnology alimentary system respiratory system urogenital system endocrine glands – endocrinology Cardiovascular system – Angiology Nerve system – Neuroanatomy sense organs and integument, skin Prof. Dr. Nikolai Lazarov 4 Methods of morphological investigations Dissection, Gr. anatemnein = separate HIC MORTUI VIVOS DOCENT Ink injection technology Corrosion method Plastination Graphic and plastic reconstruction Imaging anatomy: Roentgen anatomy X ray computed tomography (CT) Magnetic resonance imaging (MRI) Microscopic techniques: Light microscopy Electron microscopy Experimental anatomy Prof. Dr. Nikolai Lazarov 5 Regional texture of the human body
Parts of the body: head, caput neck, collum trunk, truncus thorax, thorax abdomen, abdomen pelvis, pelvis extremities (limbs) upper, membrum superius lower, membrum inferius
Prof. Dr. Nikolai Lazarov 6 Major axes and planes in the human body
Three main axes and planes:
sagittal axis – anterior posterior
transversal axis – transverse
longitudinal axis – superior inferior
sagittal plane – median section
transversal plane – axial section
frontal plane – coronal section
Prof. Dr. Nikolai Lazarov 7 Spatial orientation in the human body
Spatial terminology: (main axes of the human body ) frontal plane – frons,tis m. anterior,us = ventralis,e posterior,us = dorsalis,e sagittal plane – sagitta,ae f. medialis,e ↔ lateralis,e proximalis,e ↔ distalis,e median plane sinister ↔ dexter transversal (horizontal) plane superior,us = cranialis,e inferior,us =caudalis,e Prof. Dr. Nikolai Lazarov 8 Anatomical Nomenclature Nomina Anatomica
End of 19 th century – over 50 000 anatomical terms 1895 – Basle Nomina Anatomica (BNA ): 5528 anatomical terms 1933 – Birmingham Revision (BR ) 1935 – Jena Nomina Anatomica (JNA ) 1955 – Parisiensia Nomina Anatomica (PNA, NA ): 5640 anatomical terms Revisions of Nomina Anatomica : 1960 – New York 1965 – Wiesbaden 1970 – Saint Petersburgs (formerly Leningrad) 1975 – Tokyo 1980 – Mexico City 1983 – last 5th edition of Nomina Anatomica 1985 – Nomina Histologica and Nomina Embryologica 1998 – Terminologia Anatomica (TA ) Prof. Dr. Nikolai Lazarov 9 Objective of cytology, histology and embryology
Cytology – now Cell Biology: (Gr. κύτος, kytos, a hollow + logos, study)
Histology: (Gr. ἱστός , histos, web or tissue + logos ) general histology special histology = microscopic anatomy of organs
Embryology: (Gr. έ βρυον, embryon + logos ) general embryology (embryogenesis) special embryology (organogenesis)
Prof. Dr. Nikolai Lazarov 10 Levels of organization
Levels of organization: cell tissue organ organ system organism The cell: the basic structural and functional unit of all known living organisms the smallest unit of life – the building block of body Major cell abilities: reproduction by cell division the functioning of a cell depends upon its ability to extract and use chemical energy stored in organic molecules response to stimuli such as changes in temperature, pH or levels of nutrients cell contents are contained 11 within a cell surface membrane Prof. Dr. Nikolai Lazarov 11 The cell – evolutionary levels The biological universe consists of two cell types:
Prokaryotic cells (Gr. πρό (pro ) "before" + καρυόν (karyon) “nut or kernel", referring to the cell nucleus ) bacteria and archaea Eukaryotic cells – "true nucleus" (Gr. eυ (eu), "good", "true") multicellular organisms internal compartmentalization
Prof. Dr. Nikolai Lazarov 12 The cell – external morphology 200 different cell types that come in an astounding assortment of shapes and sizes: size – 5 200 µm small sized – up to 10 µm medium sized – 10 20 µm large sized – > 20 µm shape – related to their function: spherical spindle shaped squamous, cuboidal ... color: colorless pigmented
Prof. Dr. Nikolai Lazarov 13 The cell – chemical composition
essential elements: macroelements – 98 99% of the cell mass C, N, O, H microelements – up to 0.000001% Cu, Zn, Mg ultra trace elements – ≤0.000001% Hg, Ag, U, Ra water – 70 80% exogenous – ⅔ endogenous – ⅓ inorganic molecules: free – ions bound with organic molecules organic compounds: carbohydrates lipids proteins 14 nucleic acids Prof. Dr. Nikolai Lazarov 14 Basic cellular architecture
nucleus (Lat., nux, nut) cytoplasm (Gr. kytos , cell + plasma , thing formed) organelles (“little organs”) universal and specialized membranous (membrane limited) nonmembranous cytoplasmic inclusions deposits of carbohydrates, lipids, and pigments cytosol (cytoplasmic matrix )
Prof. Dr. Nikolai Lazarov 15 Plasma (cell) membrane
Plasma membrane , synonym: plasmalemma (Gr. lemma = 'husk') thickness – 8 10 nm (EM) asymmetrical Chemical composition: lipids – 20 40% phospholipids steroids (cholesterol) glycolipids – 2 10% proteins – ~50% hydrophobic – structural hydrophilic – receptors and enzymes >30 carbohydrates – 10% glycoproteins glycolipids glycocalyx 16
Prof. Dr. Nikolai Lazarov 16 Fluid mosaic model
Lipid protein mosaic model structural skeleton – phospholipid double layer globular proteins: Seymour integral membrane proteins, Jonathan Singer (single pass and multi pass (1924-) transmembrane proteins) peripheral proteins freeze fracture: P face (protoplasmic) Е face (extracellular)
Garth L. Nicolson (1943-)
Prof. Dr. Nikolai Lazarov 17 Membrane proteins – structure and functions
Membrane proteins: ~50% w/w in the plasmalemma synthesized in the rough endoplasm reticulum their molecules are completed in the Golgi apparatus transported in vesicles to the cell surface Functional categories: transport proteins structural proteins (membrane anchored) receptor proteins enzymes
Prof. Dr. Nikolai Lazarov 18 Cell coat (glycocalyx)
First description – Yamada (1955) Synonym = glycolemma thickness – up to 100 nm renewal – 6 8 h PAS positive Chemical composition: glycolipids cerebrosides gangliosides glycoproteins proteoglycans hyaluronic acid Functions : defense absorption immunologic role cell recognition cell adhesion Prof. Dr. Nikolai Lazarov 19 Cell surface modifications
4 types structural specializations: (Gr. mikros, small + Lat. villus, tuft of hair) Microvilli: cytoplasmic processes, 1 µm high;0.08 µm wide brush (striated) border core of actin filaments terminal web Basal cell surface folds: interdigitations Stereocilia: non motile microvilli of unusual length ductus epididymis hair cells of the ear
Cilia & Flagella Prof. Dr. Nikolai Lazarov 20 Intercellular junctions 3 types intercellular junctions:
Barrier (impermeable) junctions: tight junction, zonula occludens occluding strip, fascia occludens occluding spot, macula occludens
Adhering (anchoring) junctions: punctum adhaerens belt desmosome, zonula adhaerens spot desmosome, macula adhaerens (Gr. desmos, band + soma, body) Communicating junctions: gap junction, nexus synapse 21 Junctional complex Prof. Dr. Nikolai Lazarov 21 Membrane-limited organelles
Endoplasmic reticulum Annulate lamellae Mitochondria Golgi apparatus Lysosomes Proteasomes Secretory vesicles Transport vesicles Peroxisomes Coated vesicles 22
Nucleus Prof. Dr. Nikolai Lazarov 22 Endoplasmic reticulum
Endoplasmic reticulum: rough smooth
rough endoplasmic reticulum
protein synthesis 23 Prof. Dr. Nikolai Lazarov 23 Rough (granular) endoplasmic reticulum
Structure: cisternae – 7 8 nm ribosomes Functions: protein synthesis and segregation: intracellular utilization extracellular export initial glycosylation of glycoproteins phospholipid synthesis Prominent in protein synthesizing cells: blast cells exocrine gland cells plasma cells
neurons Prof. Dr. Nikolai Lazarov 24 Smooth (agranular) endoplasmic reticulum
Structure: tubular cisternae – 6 7 nm lacks the associated ribosomes Functions: lipid absorption and metabolism glycogen metabolism synthesis of steroid hormones regulation of Ca 2+ concentration drug detoxification Well developed in: steroid producing cells: cells of adrenal cortex interstitial cells of gonads other cell types: liver cells (hepatocytes) skeletal and cardiac muscle cells – sarcoplasmic reticulum nerve cells (neurons) glandular cells Prof. Dr. Nikolai Lazarov 25 Golgi Apparatus
ital . – apparato reticolare interno: Cammillo Golgi, 1886, 1898 Cammillo Synonyms: Golgi Golgi complex (1843 1926) Golgi zone Golgi bodies Ultrastructure: A. Dalton, M. Felix, 1953 Dictyosome: stacks of smooth membrane limited:
3 12 flattened cisternae (50 200 nm)
vesicles (30 50 nm)
large, clear vacuoles (200 300 nm) 26 Prof. Dr. Nikolai Lazarov 26 Golgi Apparatus – structure
both morphologically and functionally polarized structure:
Prof. Dr. Nikolai Lazarov 27 Golgi Apparatus – functional polarity
trafficking and sorting of proteins: glycosylation, sulfation, phosphorylation , and limited proteolysis of proteins initiates packing, concentration, and storage of secretory products
Prof. Dr. Nikolai Lazarov 28 Secretory vesicles
Secretory granules: shape – spherical diameter – 0.15 µm >1 µm clathrin coated vesicles core – histamine, chromogranin В, secretogranin ІІ
Neurosecretosomes – hormones
Zymogen granules – digestive enzymes Synaptic vesicles – transmitters
Prof. Dr. Nikolai Lazarov 29 Lysosomes (Gr. lysis , dissolution or destruction + soma , body) Discovered by Christian de Duve, 1955
Christian de Duve (1917 )
Spherical organelles: size – 0.05 0.5 m single layer (unit) membrane – 6 nm lysosomal matrix – pH 5 favorable for enzymatic activity more than 40 hydrolytic enzymes
Prof. Dr. Nikolai Lazarov 30 Lysosomes – stages
Primary lysosomes: inactive enzymes Secondary lysosomes (phagosomes, phagolysosomes): heterolysosomes (heterophagosomes) autophagosomes (autophagic vacuoles) residual bodies (telolysosomes) lipofuscin droplets pinocytotic vesicles multivesicular bodies
Prof. Dr. Nikolai Lazarov 31 Lysosomes – "suicide-bags" or "suicide-sacs" (autophagy – self digestion , Gr. auto , self + phagy , to eat)
autophagic cell death – a form of programmed self destruction (autolysis)
the cells' garbage disposal system Prof. Dr. Nikolai Lazarov 32 Peroxisomes (microbodies)
identified by EM as organelles by Christian de Duve , 1967 Gr. peroxide + soma, body microbodies: Rhodin, 1954 Spherical organelles: 70 100/cell size – 0.5 3 m (macroperoxisomes) microperoxisomes – 0.1 0.3 m homogeneous matrix (crystalloid core or nucleoid) marginal plate single layer membrane – 6 8 nm
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Prof. Dr. Nikolai Lazarov 33 Peroxisomes – structure and function
Enzymes : >50 catalase – 40% peroxidase β oxydase of very long chain fatty acids D and L amino oxydases urate oxidase
Functions : a compartment for oxidation reactions:
decomposes H 2O2 to H 2O and O 2 and eliminates it degrades several toxic molecules and prescription drugs involved in lipid biosynthesis
important role in cellular respiration Prof. Dr. Nikolai Lazarov 34 Mitochondria vitally staining – Janus green B Gr. mitos , thread + chondros , granule: Carl Benda, 1898 First observations: Kölliker, 1850 Flemming, 1882 R. Altman, 1890: bioblasts Size: 0.5 1 m wide length up to 10 m Number – varying: fibroblasts – 100 hepatocytes – 800 (25%)
oocytes – 300 000 Prof. Dr. Nikolai Lazarov 35 Mitochondria – structure
Ultrastructure: G. Palade, F.S. Sjöstrand, 1952 two mitochondrial membranes:
outer (6 7 nm) ~50% proteins and lipids: transport proteins (porin) enzymes: oxidases, hydrolases, transferases, enzymes of fatty acid metabolism, cytochromes inner : 80% proteins and cardiolipin reductases, oxidases, dehydrogenases, ATP synthase, transferases, cytochromes enzymes for oxidative phosphorylation and for electron transport system (cytochromes) forms cristae (tubules) – intracristal space attached elementary particles intramembranous space (outer chamber) – 4-10 nm matrix – intercristal (matrix) space Prof. Dr. Nikolai Lazarov 36 Mitochondria – structure and function
Mitochondrial matrix: (intercristal space; inner chamber) rich in proteins, DNA, RNA matrix granules: 30 50 nm; storage site for divalent cations – Ca 2+ , Mg 2+ mitoribosomes (mrRNA): 15 20 nm mitochondrial mRNA, tRNA circular DNA: 2 3 nm RNA and DNA polymerases Krebs cycle enzymes enzymes for lipid synthesis enzymes for protein synthesis Origin of mitochondria: evolutionary from an ancestral aerobic prokaryote adapted to an endosymbiotic life (intracellular symbiosis) new mitochondria – from preexisting mitochondria 37 by growth and subsequent division (fission) Prof. Dr. Nikolai Lazarov 37 Mitochondria – the power plants of the cell
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Prof. Dr. Nikolai Lazarov 38 Cell Nucleus
R. Brown, 1831 – (Lat. nucleus, kernel; Gr. karyon , nut) in all eukaryotic cells – with exception of Er number – uninuclear , binuclear , multinuclear cells localization – centrally or peripherally Robert Brown external morphology: (1773 1858) shape – species diversified size – 10% of the cell volume; 5 µm (spermatozoon), 40 µm (oogonium)
Prof. Dr. Nikolai Lazarov 39 Nucleus – structure
Structural components: nuclear envelope chromatin nucleolus nuclear matrix (nucleoplasm)
Prof. Dr. Nikolai Lazarov 40 Nuclear envelope
First description : M. Watson , 1955 Ultrastructure: outer nuclear membrane – 6 nm ribosomes rER vimentin filaments inner nuclear membrane – 6 nm nuclear lamina – 100 300 nm lamins A, B, C chromatin perinuclear space – 10 40 nm nuclear pores
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Prof. Dr. Nikolai Lazarov 41 Chromatin
First description: W. Flemming, 1882 Heterochromatin (condensed ) – 90% Gr. heteros, other + chroma , color: marginal chromatin – nuclear membrane chromocenters – nucleoplasm nucleolar associated chromatin: perinucleolar intranucleolar constitutive heterochromatin – inactive, around the chromosome centromere and near telomeres facultative heterochromatin euchromatin and sex chromatin Euchromatin (extended) – 10% Gr. eu, good, true: a lightly packed form of chromatin (DNA, RNA and protein) comprises the most active portion of the genome within the cell nucleus – replication and transcription Prof. Dr. Nikolai Lazarov 42 Sex chromatin
synonym: Barr body – only in females Barr, Bertram, 1949 tightly packed inactive Х chromosome localization: adhering to the nuclear envelope diameter – 1 µm “drumstick like” appendage to the nuclei Murray L. Medical application: Barr diagnostics in endocrinology (1908 1995) forensic medicine practice study of inherited chromosome anomalies – Klinefelter's and Turner syndromes etc. disclosure of the genetic sex – in hermaphroditism and pseudohermaphroditism
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Prof. Dr. Nikolai Lazarov 43 Nucleolus
First description: Fontana, 1774 Number: 1 max. 10: metabolically active cells embryonic cells during proliferation rapidly growing malignant tumors External morphology: non membrane bound structure shape – spherical; compact, reticular, annular etc. diameter – 1 3 µm Formation: nucleolar organizers – short arms of chromosomes 13, 14, 15, 21 and 22 (the acrocentric chromosomes)
Prof. Dr. Nikolai Lazarov 44 Nuclear matrix
synonyms : nucleoplasm, karyoplasm a highly dynamic structure Composition – amorphous: proteins + RNA – nucleoskeleton nuclear lamina – lamins A, B, C numerous enzymes metabolites ions crystalline inclusions viruses and other inclusions
Prof. Dr. Nikolai Lazarov 45 Ribosomes
small electron dense particles, 20 x 30 nm in size
George Emil 1943 – Albert Claude “microsomes” Palade 1955 – George Palade Palade granules (1912 2008) 1958 – Richard B. Roberts “ribosomes” The Nobel Prize 65% rRNA and 35% ribonucleoproteins in Physiology or Medicine 1974
"for studies of the structure and function of the ribosome" Prof. Dr. Nikolai Lazarov 46 Ribosomes
free ribosomes proteins for use within the cell monosomes and polyribosomes (polysomes) bound ribosomes (ribophorins І and ІІ) secretory proteins (Ig, collagen, hormones) Prof. Dr. Nikolai Lazarov 47 Protein synthesis
2 principal stages:
transcription – in the cell nucleus
translation – in the cytoplasm: initiation elongation termination Signal hypothesis for the synthesis of secretory proteins
Prof. Dr. Nikolai Lazarov 48 Cytoskeleton
Gr. kytos, cell + skeleton, dried body , ‘misshapen', amorphos
Paul Wintrebert 1931
Prof. Dr. Nikolai Lazarov 49 Microtubules nonbranching, elongated hollow cylinders, made of protein Gr. micros , small + tubulus , tubule a left handed helix, formed by F Actin polymers
outer diameter = 24 25 nm, varying length = several µm seen only under EM – first described in 1963 dynamic instability – after fixation: stabile labile
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Prof.Prof. Dr.Dr. NikolaiNikolai LazarovLazarov 50 Microtubules – structure
arranged as a ring of 13 protofilaments main component – dimeric tubulin (alpha&beta) isolated in 1975
wall – 5 nm thick; hollow core – 14 nm wide Prof. Dr. Nikolai Lazarov 51 Microtubules – functions
component of the cytoskeleton – development and maintenance of cell shape intracellular transport of other organelles: motor proteins (kynesins and dyneins) formation of the mitotic spindle
antimitotic alkaloids – experimental inhibition of mitosis: colchicine vinblastine cancer treatment (chemotherapy) vincristine basis for formation of centrioles, basal bodies,
cilia and flagella Prof. Dr. Nikolai Lazarov 52 Cilia and flagella
axoneme and basal bodies – highly organized microtubule core
Prof. Dr. Nikolai Lazarov 53 Cell center
synonym: centrosome
Oscar Hertwig first observation: Oscar Hertwig , 1875 1849 1922 ЕМ description: Bessis , 1955
diplosome (a pair of centrioles) centrosphere
Prof. Dr. Nikolai Lazarov 54 Centriole – structure barrel shaped cell structure composed of microtubules
diameter: 0.15 0.2 µm length: 0.3 0.7 µm structure: 9 triplets (9 x 3) + 0 centriolar satellites: 40 70 nm microtubule organizing centers
Prof. Dr. Nikolai Lazarov 55 Centriole – functions
role in cell division: formation of mitotic spindle
role in generation of the cell's cytoskeleton: formation of cilia and flagella building of their basal bodies
Prof. Dr. Nikolai Lazarov 56 Microfilaments up to 10% of the total protein of some nonmuscle cells
Actin filaments – thin filaments: the thinnest filaments of the cytoskeleton located close to the cell membrane grouped as bundles or networks linear polymers of actin subunits
cytochalasin: blocks actin polymerization phalloidin: promote actin polymerization ; stabilize actin polymers Prof. Dr. Nikolai Lazarov 57 Intermediate filaments
• Nuclear lamins: А, B, C
Prof. Dr. Nikolai Lazarov 58 Cytoplasmic inclusions
small particles of insoluble substances suspended in the cytosol
synonyms: deutoplasm, paraplasm Cytoplasmic deposits: proteins: secretory granules glycogen granules lipid inclusions (fat droplets) crystalline inclusions pigments: exogenous endogenous
Prof. Dr. Nikolai Lazarov 59 Membrane transport
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Prof. Dr. Nikolai Lazarov 60 Exocytosis
Gr. ἔξω , out + κύτος , cell
secretion of: modes of secretion: components of extracellular merocrine matrix (collagen) apocrine protein hormones (insulin) holocrine serum proteins Prof. Dr. Nikolai Lazarov 61 Endocytosis
the process by which cells absorb molecules from outside the cell Gr. endon , within three main types of endocytosis: phagocytosis (literally, cell eating) pinocytosis (literally, cell drinking) receptor mediated endocytosis
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Prof. Dr. Nikolai Lazarov 62 Cell signaling
a complex system of information signals: communication designed for: perceiving of cell integrity maintenance of optimal tissue homeostasis coordination of cell actions
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Prof. Dr. Nikolai Lazarov 63 Ways of signaling
Prof. Dr. Nikolai Lazarov 64 Kinds of communication
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Prof. Dr. Nikolai Lazarov 65 Cell cycle
G0 phase: a specialized resting state cycle duration – 15 20 h mitosos (M phase) – 30 60 min interphase:
G1 phase (presynthetic) – 5 10 h S phase (synthetic) – 6 8 h
G2 phase (postsynthetic) – 2 5 h
Prof. Dr. Nikolai Lazarov 66 Cell division
the process by which a parent cell divides into two or more daughter cells
Mitosis: somatic cells Endomitosis:megakaryocytes (polyploid amitosis) Amitosis: osteoclasts Meiosis: gametes (reductional division)
Prof. Dr. Nikolai Lazarov 67 Mitosis
Gr. mitos, a thread
Mitotic (M phase) of the cell cycle: prophase: 10 60 min metaphase: 10 20 min anaphase: 5 8 min telophase: 20 30 min cytokinesis
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Prof. Dr. Nikolai Lazarov 68 Meiosis
Gr. meiosis, a lessening
Phases of meiosis – two consecutive cell divisions: Іst meiotic division: (reduction in chromosome number) – prolonged phophase: leptotene (leptos =thin) zygotene (zygon =yoke): bivalents conjugation pachytene (pachy =thick): tetrads crossing over diplotene (diplos =double) diakinesis (dia =through ) ІІ nd meiotic division: (reduction in the amount of genetic material (DNA) – similar to mitosis: without S phase 69
haploid chromosome number Prof. Dr. Nikolai Lazarov 69 Cell proliferation
Fr. proliferer, to increase
Proliferation: a rapid increase in the number of cells
Prof. Dr. Nikolai Lazarov 70 Cell differentiation
Differentiation: structural and functional specialization of the cell Three categories of specialized cells: fully differentiated, non dividing cells potentially dividing cells not terminally differentiated, renewal by stem cells: unipotent cells pluripotent (multipotent) cells potency – the capacity to differentiate into specialized cell types71 Prof. Dr. Nikolai Lazarov 71 Necrotic cell death
Gr. nεκρός, death
Necrosis – cell death caused by external factors, such as infection, toxins or traum: karyopyknosis (Gr. pyknos = thick) karyorrhexis (Gr. rhexis = to tear) karyolysis (Gr. lysis = dissolution)
Prof. Dr. Nikolai Lazarov 72 Programmed cell death
Gr. apo, from + ptosis , falling
Apoptosis or programmed cell death – death of a cell, mediated by an intracellular program
Pathways – caspases : receptor pathway mitochondrial pathway
Phases : latent executive Prof. Dr. Nikolai Lazarov 73 Thankyou74… Prof. Dr. Nikolai Lazarov