Cytogenetics Lesson 3-4 BMLS 2E PDF

Topic 3: Stem Cells, Human Microbiome, Meiosis, Development [MT 203] & Aging SY 2024-2025...

Topic 3: Stem Cells, Human Microbiome, Meiosis, Development [MT 203] & Aging SY 2024-2025 1ST SEMESTER MT-CYTOGENETICS [MS. DAYAN JUMAMOY] Prepared by: Lance, Kezziah Rapha D. PATHWAY TO CELL SPECIALIZATION OUTLINE I. Stem Cells II. Human Microbiome III. Reproductive System IV. Meiosis V. Development VI. Aging STEM CELLS Undifferentiated cells with remarkable ability to develop into specialized cell types and regenerate tissue. Self Renewal: ability to continue the lineage of cells that can divide to give rise to another cell like itself. PROGENITOR CELL Partially differentiated stem cells and has the potential to differentiate into specific cell type within a particular tissue or organ It cannot self-renew Developmental Potential of Stem Cells & Progenitor Cell Progenitor Cell Definition can give rise to every cell Totipotent type Their daughter cell have fewer possible fates The Germ Layer: a. Ectoderm - skin, Pluripotent nervous system b. Mesoderm - muscle c. Endoderm - internal organs Their daughter cell have only a few developmental choices Multipotent Hematopoietic Stem Cell: an immature cell that can develop in all Stem Cells to Develop Treatment for Variety of types of blood cells. Diseases & Injury 1. Donor Stem Cell - bone marrow and umbilical cord 2. Own Cell (unaltered) - bone marrow - Own Cell Reprogram: to put a certain cell to its specific type of cell. KRDL | BMLS 1  TOPIC 3 CYTOGENETICS BMLS 2E STEM CELLS IN TREATMENT FOR DISEASE HUMAN MICROBIOME Organism inhabiting another organism MICROBIOME All organism that live in and on another organism Habits, experience, & environmental exposure influence the makeup of our microbiome - Fiber promotes growth of microbiome - Overly Hygienic: limits exposure to pathogens - Stress: will affect the exposure to pathogens Gut Microbiome: 10 trillion bacteria help in digesting certain foods Probiotic: live microorganism such as bacteria (Lactobacillus) & yeast that when ingested, confer a health Fecal Transplantation: treatment based on altering the microbiome that replaces hundreds of microbiome that replaces hundreds of STEM CELL SOURCES bacterial species at once - Replaces the flora in the intestine Stem Cell Type Source - Clostridium specie Inner cell mass of very early embryo; somatic cell Facts about the Human Microbiome Embryonic Stem nuclear transfer into the Cell 1. Certain Skin bacteria causes acne but other egg cell Pluripotent keep skin clear 2. Circumcision protect against certain viral Genes/other chemicals infection like HIV reprogram somatic cell Induced Pluripotent 3. Lowered blood sugar following weight loss nucleus; no embryos Stem Cell (iPS) surgery is partly due to changed gut required. microbiome Pluripotent 4. An altered microbiome hasten starvation in Somatic cell that normally malnourished children function as stem cell, 5. Antibiotics temporarily alter the gut from any stage of microbiome Adult Stem Cell developmental, from 6. The birth of agriculture 10,000 years ago fertilized ovum through introduced the bacteria that cause dental elderly caries Multipotent 7. Microbiome imbalances may contribute to or cause asthma, cancer, obesity, psoriasis, APPLICATION OF STEM CELL: Crohn's disease, gum disease and other conditions. 1. Drug discovery and development 8. Babies born by cesarean section (surgically) 2. Observation of earliest signs of a disease have different microbiomes that babies born 3. Creation of tissue & organs for use in implants vaginally. or to study (bone marrow transplant) 4. Creation of iPS cell Stem Cell Possibilities Can be any one of the 220 different cells in the body KRDL | BMLS 2  TOPIC 3 CYTOGENETICS BMLS 2E MEIOSIS, DEVELOPMENT & AGING Also makes inhibin B (plays a role in sperm The Reproductive System production), insulin like factor 3 (which helps The Male: develop the testes).. Etc. It also produces sperm within the coiled masses of tubes called seminiferous tubules long , coiled tube that rests on the backside of each testicle Transports and stores sperm Epididymis Its job is to bring sperm to maturity During sexual arousal, Sperm Cells develop within a 125-meter-long contractions forces the network of seminiferous tubules. sperm into the vas - Are packed into paired, oval organs called defense testes. Long, muscular tube that PARTS OF THE MALE REPRODUCTIVE SYSTEM travels from the PART DEFINITION epididymis into the pelvic Male organ used in sexual Vas deferens cavity intercourse Transports mature sperm Three parts: cell to the urethra in - Root; attaches to the preparation for ejaculation wall of the abdomen - Glans; cone shaped Formed by the fusion of Penis part at the end of a the vas deferens and penis Ejaculatory ducts seminal vesicle - Body The ejaculatory ducts The tip of the penis is the empty into the urethra opening of the urethra Tube that carries the pee which transports semen from the bladder to Urethra and pee outside of the body Loose pouch like sac of It also ejaculates semen skin that hangs behind Sac like pouches that and below the penis. attach to the vas deferens Contains the testes near the base of the Acts as the climate bladder Seminal Vesicles control system for the Produces fructose that Scrotum testes; for the testes to provides energy to the develop sperm, the sperm to help it move scrotum gives off a cooler during ejaculation temperature and moves Located below the the testes away from the bladder and front of the body. rectum Oval organs about the Helps flourish the sperm size of large olives that lie Prostate gland Converts some of the in the scrotum testosterone to Testicles (Testes) Responsible for making dihydrotestosterone (DHT) testosterone (primary that plays a role in sexual male sex hormone) development KRDL | BMLS 3  TOPIC 3 CYTOGENETICS BMLS 2E Called the Cowper’s Supports stromal and glands, this produces a vascular tissue clear, slippery fluid that Induces uterine empties directly into the contractions Bulbourethral Gland urethra The inner lining of your Serves as lubricant for the uterus urethra and neutralizes Preparation for the acidity left from pee. Endometrium implantation, maintenance of The Female: pregnancy if implantation occurs Top part of the uterus that us across from the cervix Fundus Stores gas and a byproduct of digestion Finger like projection on the ends of your fallopian tube closest to your Fimbriae ovaries Catch the egg that one of your ovaries releases during ovulation Paired tubular sex organs PARTS OF THE FEMALE REPRODUCTIVE SYSTEM in the human female body PART DEFINITION Uterine Tube that stretch from the A muscular canal that ovaries to the uterus Vagina joins the cervix to the outside of the body A hollow, pear shaped Function of Reproductive System organ that holds a fetus during pregnancy 1. Production of gametes through Gonads Divided into two parts: 2. Fertilization Uterus 3. Development & nourishment of individual Cervix and Corpus; larger part of the uterus that 4. Production of reproductive hormone expands during pregnancy Gametes or Sex Cell: Sperm & Oocytes Small, oval shaped Each System Has: glands that are located on - Paired structure, called gonads, where the Ovaries either side of the uterus sperm and oocytes are manufactured Produces egg and - Tubular structures that transport these cells hormones - Hormone and secretions that control Narrow tubes attached at reproduction the upper part of the uterus and serve as Meiosis pathways for egg (ovum) to your uterus A type of cell division Fallopian Tube Where gametes form from special cells called Fertilization of an egg by sperm normally occurs in germline cells, halves chromosomes the fallopian tube Maturation: a further process, sculpts the The fertilized egg then distinctive characteristics of sperm and oocyte. move to the uterus Gametes: contribute 23 different chromosomes, constituting one copy of the genome, a fertilized Middle layer of the uterine Myometrium ovum. wall KRDL | BMLS 4  TOPIC 3 CYTOGENETICS BMLS 2E Somatic Cells: 23 pairs of chromosomes or 46 in d. Diplotene (Diplonema) total - Synaptonemal complex start to Homologous Pairs: have the same genes in the dissolve, but homologous same order but may carry different allele or chromosomes remain attached at variants of the same gene points called chiasmata Haploid: only one each type of chromosome - Chromosomes continue to condense Diploid: two copies of each chromosome type e. Diakinesis Without Meiosis: sperm and oocyte would each - Chromosomes further condense contains 46 chromosomes, fertilized ovum have - Nuclear envelope breaks down twice the normal number of chromosomes or 92 completely Polypoid: genetically overload cell, undergoes - Spindle apparatus start to form only a few cell division before stopping 2 Divisions of Genetic Material First Division: Reduction Division (Meiosis 1) - Reduces the number of replicated chromosome from 46 to 23 Second Division: Equational Division (Meiosis 2) - Produces four cells from the two cells formed in the first division by splitting the replicated chromosomes Meiosis 1 - Reduction Division Begins as the replicated chromosomes condenses METAPHASE I Visible when stained The greater the no. of chromosomes, the greater the genetic diversity that will be generated Homologous chromosomes pairs align along the equatorial plane (metaphase plate) of the cell Spindle fibers from opposite poles attach to each homologous chromosome, specifically to the protein structure (kinetochores) ANAPHASE I Homologous chromosomes separate and migrate toward opposite poles of the cell (disjunction) Sister chromatids remain attached to each other PROPHASE I a. Leptotene (Leptonema) TELOPHASE I & CYTOKINESIS - Chromosomes condenses Chromosomes reach their respective poles - homologous chromosomes start to Nuclear envelope starts to form around each set pair up of chromosomes - Nuclear envelope begins to break Cytokinesis: cell divides into 2 daughter cells down b. Zygotene (Zygonema) Meiosis II - Equational Division - Homologous chromosomes continue to pair up forming a synaptonemal Similar to mitosis complexes (synapsis) Each chromosome which exists as a pair of c. Pachytene (Pachynema) chromatids becomes aligned along the center of - Homologous chromosomes becomes the cell then splits leading to the formation of 2 fully paired & genetic recombination new daughter gametes (total of 4) occurs Prophase II, Metaphase II, Anaphase II, - Crossing over occurs Telophase II KRDL | BMLS 5  TOPIC 3 CYTOGENETICS BMLS 2E REDUCTION DIVISION (MEIOSIS I) Each primary spermatocyte divides, forming two equal sized haploid cells called secondary spermatocytes. MEIOSIS II Comparison of Meiosis & Mitosis Each secondary spermatocyte divides to yield two equal sized spermatids Each spermatid then develops the characteristic sperm tail or flagellum. SPERM Only develops in 74 days A mere 0.006 centimeter (0.0023 inch) long Must travel about 18 centimeter (7 inches) to reach an oocyte Parts/Formation: 1. Base of the Tail - has many mitochondria - Which will split ATP molecules to SPERMATOGENESIS release energy that will propel the sperm inside the female reproductive Transformation of sperm cells begins in a diploid tract stem cell called a spermatogonium 2. After spermatid differentiation - some of the This cell divides mitotically, yielding 2 daughter cytoplasm connecting the cells falls cells (4 total) away, leaving mature, tadpole- One cell continues to specialize into a mature shaped spermatozoa (singular) or sperm sperm Other daughter cell remains a stem cell able to 3. Acrosome - membrane covered area on the self renew and continually produce more sperm. front end - Contains enzyme that help the sperm cell penetrate the protective layers around the oocyte - Within the large sperm head, DNA wraps around proteins - The sperm’s DNA at this time is genetically inactive KRDL | BMLS 6  TOPIC 3 CYTOGENETICS BMLS 2E OOGENESIS (Egg Making) Additional Info Meiosis in the female Before Birth: female has a million or so oocytes Begins in diploid cell called oogonium arrested in prophase 1 Unlike male cells, oogonia are not attached to Puberty: around 400,000 oocytes remain each other, Instead, follicle cells surround each After Puberty: meiosis I continues in 1 or several oogonium oocytes each month but halts again at As each oogonium grows metaphase II - Cytoplasm accumulates Ovulation: ovary releases a secondary oocyte in - DNA replicates response to specific hormonal cues each month. - Cell becomes a primary oocyte - A female ovulates 400 oocytes between puberty and menopause. AGE EFFECT CONDITION Diseases Phenotype Achondroplasia Short limbed dwarfism Premature fusion of skull bones in infants, causing wide spaced & Crouzon Syndrome bulging eyes, beaked nose, short upper lip, small upper jaw & jutting lower jaw Thin hair, weak bones, tough & Hutchinson - Gilford wrinkled skin, stiff joints & jutting Progeria Syndrome lower jaw Multiple Endocrine Cancers of thyroid, parathyroid & MEIOSIS I Neoplasia 2 adrenal glands Premature fusion of skull bones in Primary oocyte divides into two cells; a small cell Pfeiffer Syndrome infancy, short & fused fingers & with very little cytoplasm called a first polar body, toes and a much larger cell called a secondary Thanatophoric oocyte. Severe short limbed dwarfism Dysplasia Each cell is haploid, with the chromosomes in replicated form Prenatal Development MEIOSIS II A prenatal human is considered an embryo for The tiny first polar body may divide to yield two the first 8 weeks, when rudiments of all body polar bodies of equal size with unreplicated parts form chromosomes, the first polar body may 1st Week: the embryo is in “preimplantation” decompose stage because it has not yet settled to the uterine The secondary oocyte, however divides lining unequally in meiosis 2 to produce small polar 2nd Week: consider a prenatal human to be an body with unreplicated chromosomes and the embryo when it begins to develop tissue layers mature egg cell or ovum, which contains a large After the 8th Week: fetal period, when structure volume of cytoplasm grow and specialize From the start of the 9th week until birth: the Blighted Ovum prenatal human organism is a Fetus A sperm fertilized the polar body. When this happens, Fertilization the woman’s hormone responds as if she is pregnant but a disorganized clump of cells that is not an Process by which a sperm cell fuses with an egg embryo grows for a few weeks and leaves the cell in the formation of a fertilized egg woman’s body A sperm cell can survive in a woman’s body for up to 3 days Oocyte can only be fertilized in the 12 to 24 hours after ovulation KRDL | BMLS 7  TOPIC 3 CYTOGENETICS BMLS 2E The woman’s body helps sperm reach an oocyte Gastrula Capacitation: process in the female; chemically activates sperm, then the oocyte secretes a Primordial embryo chemical that attracts sperm Amniotic Cavity: space that forms between the Corona radiata: a covering of follicle cells where inner cell mass & the outer cells anchored to the a first sperm contacts that guards a secondary uterine lining oocyte Formation of 3 germ layers The sperm’s acrosome then bursts releasing - Ectoderm - outermost layer, nearest the enzymes that bore through a protective layer of amniotic cavity glycoprotein (the zona pellucida) beneath the - Mesoderm - middle layer corona radiata - Endoderm - innermost layer, closer to the Fertilization or conception begins when the outer blastocyst membrane of the sperm and secondary oocyte Primary germ layers: the cells that form the layers meet at a protein on the sperm head contacts a of the primordial embryo become determined or different type of protein on the oocyte fated, to develop specific cell types. More than one sperm can enter an oocyte, but the resulting cell has too much genetic material Multiples for development to follow Within 12 hours of the sperm penetration: the Occurrence of multiple offspring from a single ovum’s nuclear membrane disassembles and the pregnancy two sets of chromosomes called pronuclei Main Types: approach one another 1. Fraternal (Dizygotic) Twins Within each pronucleus, DNA replicates - 2 sperm fertilized 2 oocytes Fertilization complete: when two genetic package - Can happen if ovulation occurs in two meet and merge forming the genetic instruction ovaries in the same month for a new individual - Or if two oocytes leave the same Fertilized ovum is called a zygote. ovary and are both fertilized 2. Identical (Monozygotic) Twins Cleavage: From Ovulation to Implantation - Descended from a single fertilized ovum Cleavage: a period of frequent cell division - Identical twins with separate amnions Blastomeres: resulting early cells & chorions Morula: 16 more cells (came from the latin word: - Identical twins sharing an amnion & mulberry) chorion Blastocyst: thin walled hollow structure for - Identical twins sharing a chorion but which the embryo arises have separate amnions Embryo: early stages of the placental a. Conjoined (“Siamese”) development from which the fetus arises Twins The ball of cells hollows out, and its center fils - Embryo divides into with fluid, creating a Blastocyst twins after the point - Term “cyst” refers to fluid filled center at which the 2 group Inner Cell Mass are clumps on the inside lining, of cells can develop its formation is the first event that distinguishes as 2 individuals cells from each other by their relative positions. between days 12 & 15 The inner cell mass continues developing, - Occurs in 1 in forming the embryo. 50,000-100,000 Implantation: an event in which the blastocyst - Some have shared nestles into the uterine lining takes about a week organs Trophoblast: outermost cells of the blastocyst, - Some are dicephalic secretes hCG (2 heads) Human Chorionic Gonadotropin (hCG) is a hormone that prevents menstruation, this Embryo Development hormone detected in a woman’s urine or blood is one sign of pregnancy. Organogenesis: transformation of the simple three layers of the embryo into distinct organs - Appearance of primitive streak - 1st sign of a nervous system KRDL | BMLS 8  TOPIC 3 CYTOGENETICS BMLS 2E - Neural Tube Defect (NTD): neural tube does Cigarette - chemicals stress a fetus not close completely; parts of the brain/spinal a. Carbon Monoxide: crosses placenta & cord protrude from the open head/spine prevents fetus’s hemoglobin from adequately binding O2 FETUS b. Nicotine: sudden infant death syndrome, low Prenatal human organism from the start of the birth weight, hearing problems (childhood) 9th week until birth c. Other chemicals: block transfer of nutrients to Has tiny versions of all structures that will be the fetus, present at birth E-Cigarettes (Vaping); face & mouth defects Week 6: anatomical differences between sexes Alcohol - risks a fetal alcohol spectrum disorder appear after SRY gene is expressed is in males in the unborn child; fetal alcohol syndrome Weeks 9-15: Reproductive organ forms, tooth (severe) buds appear, eyelids form, fetus is very active, brain activity can be detected NUTRIENTS Week 12: sucks its thumb, kicks, makes fist & Excess of Vitamin A-based drugs & vitamin A faces, has beginnings of the teeth itself: congenital malformations (central nervous Week 16-26: brain develops rapidly, alveoli form & cardiovascular systems) and spontaneous in the lungs, internal parts of the eyes and ears abortion form, eyebrows, eyelashes and nail appear, Excess Vitamin C muscle develops Malnutrition: still birth, low birthweight, wasting Week 27-38: bones complete their development, and developmental delays head hair gets coarser and thicker, brain is continuously active VIRAL INFECTION 4th Month: hair, eyebrows, lashes, nipples & Chicken Pox: increased risk for congenital nails varicella syndrome/neonatal varicella End of 5th month: curls into head-to-knees Zika Virus: microcephaly & other brain problems position HIV: low birthweight, prematurity & stillbirth 6th Month: skin appears wrinkled German Measles: 1st trimester cataracts, Final trimester: development of organ systems deafness and heart defects, 2nd or 3rd hearing problems and type 1 diabetes mellitus Birth Defect MATURATION & AGING Structural changes present at birth that can affect almost any part of the body Maturation Critical period: the time when genetic abnormalities, toxic substances, or viruses can Process of developmental and growth towards alter a specific structure. physical and physiological maturity Teratogens: chemicals or other agents that Involves the sequential and orderly development cause birth defect of an individual from infancy to adulthood Aging TERATOGENS Greek for “monster-causing” Moving through the life cycles Drugs (Thalidomide) - mild tranquilizer to Gradual deterioration and functional decline alleviate nausea early in pregnancy, resulting (physiological function) that occurs as a person babies born with incomplete or missing legs and gets older arms Resveratrol: type of enzyme called a sirtuin that a. Valproic Acid: used to prevent seizures & regulates energy use in cells by altering the symptoms of bipolar disorder, rarely can expression of certain sets of genes cause NTDs, heart defects, hernias & clubfoot Adult-Onset Inherited Disease: disorders that b. Cocaine: poor self control, difficulty resemble accelerated aging (such as progeria) processing information & attention deficit (childhood), higher risk of language & memory Longevity problems & anxiety (adolescence) c. Thalidomide: mild tranquilizer to alleviate Length or duration of an individual’s life, specially nausea in early pregnancy, resulting to babies their lifespan born with incomplete or missing legs or arms KRDL | BMLS 9  TOPIC 3 CYTOGENETICS BMLS 2E Scientist study people in their 90s and 100s, including ages 105 above to determine what contribute to their long lives: reflect their lifestyle Other factors: genetics, access to healthcare, socioeconomic factors and environmental factors. Age Effect Conditions Maternal Age Effect Condition: -Birth at ages 35 above can cause Monosomy or trisomy disease (missing/extra chromosome) (such as Down Syndrome) Paternal Age Effect Condition: - Occur in genes of the fibroblast growth factor receptor form and affected skeletal growth. Syndrome that Resemble Accelerated Aging Make a person appear older that they are, but does not affect life expectancy (progeroid) Life Expectancy - average age at death for a species Lifespan - oldest known individual of a species Progeria: most severe progeroid syndromes, shortens life expectancy. KRDL | BMLS 10