Presentation on theme: "Chapter 5 The human organism and the perpetuation of life."— Presentation transcript:
1 Chapter 5 The human organism and the perpetuation of life. Topics:The cell and its functionsCell division (mitosis & meiosis)Tissues, organs and systemsThe Reproductive System
2 About CellsThe cell is the basic unit of structure and function in living thingsCells are usually microscopic, but range from the size of a bacteria to the size of an unfertilized ostrich egg.Living things contain one or more cellsProtozoans contain a single cellHumans contain billions of cells
3 CELL PARTSThe various parts of cells are known collectively as CELL PARTS.Cell parts are structures inside a cell that are too small to be living, but which together allow a cell to live.Cell parts include:Membranes, that surround the cell and nucleus.Filaments, tubules and fibres thatMacromolecules, like the DNA of chromosomes.Fluids, like the cytoplasm.Organelles and other structures inside the cell.
4 Three Main Parts of a Cell A cell usually has three distinct areas or layers:The membraneThe Cytoplasm & OrganellesThe nucleus & ChromosomesMembraneCytoplasm(with organelles)Nucleus(with chromosomes)
5 Function of the Cell Membrane The cell membrane is a flexible barrier that that surrounds the cell and allows the cell to interact with its environmentForms a protective barrierHelps absorb nutrients and useful substancesHelps eliminate wastes and other materials produced inside cells
6 Drawing of a cell membrane Copy the “simplified diagram” from the blackboard
7 Part 2: The Cytoplasm & Organelles Together, the cytoplasm and organelles are sometimes called protoplasmThe cytoplasm is the liquid portion of the cell.It is a complex mixture of materials: water, gases, wastes, nutrients, raw materialsThe OrganellesSuspended in the cytoplasm are many tiny structures called organelles. Each organelle has a specific function.
8 The Organelles Mitochondria (sing. mitochondrion). Endoplasmic reticulumRoughSmoothRibosomesGolgi ApparatusLysosomesVacuoles
9 MitochondriaThe mitochondrion is the powerhouse of the cell. Here chemical energy is released by the break down of food particles.It is a bean-shaped organelle with an internal membrane folded into many “cristae” .I am very energetic!And cute as a bean too!
10 Endoplasmic Reticulum The “ER” or Endoplasmic Reticulum is a network of tubes and membranes that runs through the cell. Its purpose is to transport materials quickly through the cellRough ERHas ribosomesSmooth ERHas no ribosomesER Transport system at your service!For when it absolutely, positively has to get to the ribosomes quick as possible.
11 RibosomesVery tiny, round organelles associated with protein synthesisThey help manufacture the cell’s proteins.We are very small, like beads. Sometimes we hang around the endoplasmic reticulum
12 Golgi Apparatus (A.K.A. Golgi body or Golgi complex) A network of membranes, similar in appearance to the ERIts purpose is to modify and “package” proteins that will be secreted.Also makes digestive enzymesI look like sort of like a stack of pancakes with blobs of syrup falling off!
13 I’ve got the digestive enzymes Lysosomes & VacuolesThese are storage areas within a cellLysosomes hold digestive enzymes that help the cell metabolize food. When a cell dies, the digestive enzymes help dissolve the dead cellVacuoles store food or waterLet’s get togetherAnd have a feast!I’ve got the digestive enzymesAnd I’ve got the food
14 All the organelles get their instructions from me. Part 3: The NucleusThe nucleus consists of:The nuclear membrane or envelope (with tiny nuclear pores in it)The nucleoplasmThe chromatin materialAKA chromosomesThe nucleolusHey!I am, like, in control, man!All the organelles get their instructions from me.
15 ExerciseColour, label and give the functions of the cell drawing.
17 Cell MembraneSmooth ERCytoplasmMitochondrionRibosomeNucleusGolgi apparatusLysosomeEndocytosis / ExocytosisNucleoplasm or “matrix” (containing chromatin)NucleolusNuclear membrane “envelope” (with nuclear pores in it)Rough ER
18 DNAa helix is a spiralshape, similar toa spring.DNA is a molecule, shaped like a double helix, usually found inside the cell’s nucleus.Facts about DNAChromosomes are made of DNAGenetic information is stored on DNADNA is the only large molecule that is able to copy itself.Trivia:DNA stands for deoxyribonucleic acid.A Helix
19 Simplified drawing of a DNA Molecule Carbon atom(gray)Hydrogenatom (white)Phosphorusatom (orange)Oxygen atom(red)NitrogenAtom (blue)Portion of a Model ofa DNA MoleculeSimplified drawing of a DNA MoleculeDNA contains carbon, hydrogen, oxygen, nitrogen and phosphorusThe atoms are arranged into a sugar-phosphate backbone, and four types of nitrogen-containing bases.
20 Some people compare the structure of DNA to a twisted ladder. The sugar and phosphate form the sides, and the base pairs make the rungs or steps.
21 GenesA Gene is a segment of DNA that contains the genetic information to carry out a particular job.That is, to make a particular protein or to control a particular feature.A Genome is a complete set of genetic information.Enough information to make a complete body and all the cells in it.A genome can contain thousands of genes
22 Genetic DiversityGenetic Diversity is the differences between individuals, achieved by all possible genetic variations of a particular species.All organisms have different individuals.The more the differences, the greater the genetic diversity.
23 Assignments Textbook: Workbook Read pp. 125 to 127 You may try questions 1 to 7 on p. 152WorkbookDo pages 67 to 70
24 Topics: Mitosis Overview Meiosis Overview Mitosis vs. Meiosis Mitosis & MeiosisTopics:Mitosis OverviewMeiosis OverviewMitosis vs. Meiosis
25 Cell Cycle OR The life of a cell: Cell grows Cell Dies Prepares for division (mitosis),Divides to daughter cells,Cycle begins againORCell Dies
27 2 Main Events of the Cell Cycle Interphase: Cell grows & prepares for Mitosis (see previous slide for diagram)Prepares 2 waysReplicates chromosomes“Tools” for mitosis are producedMitosis: Cell divides to form two genetically identical cellsOne copy of chromosomes goes into each new cell
28 Mitosis main points Starts as diploid Ends as diploid two copies of each chromosome (total=46 in humans)Ends as diploidOne diploid parent cell makes two identical diploid copies of itself. (total=46 in humans)Very small portion of cell life spent in mitosis (6%)All living and growing cells undergo mitosis
30 Meiosis main points Meiosis Enables sexual reproduction Starts with diploid cellsTwo of each chromosome type (46 in humans)Ends with haploid sperm or egg cells.Only one copy of each chromosome (23 in humans)Only cells in testicles and ovaries undergo meiosis.Meiosis increases genetic diversity due to crossing over of genes, and the mixing of two different sets of genes after fertilization
31 Mitosis in Detail Remember: Mitosis is normal cell division It is part of the cell cycleThe Rest of theCELL CYCLECell Division(MITOSIS)
32 Phases in the Cell Cycle MATRemember:= INTERPHASEPreparing for MitosisWhere’s myPee MAT?It will help you keep track of the 5 main phases of a cell’s life= PROPHASEUndergoing Mitosis= METAPHASE= ANAPHASE= TELOPHASE(and cytokinesis)
33 The Cell Cycle Cytokinesis: Metaphase: Prophase: Interphase: Anaphase: The cell splits into two new cellsMetaphase:The chromosomes line up near the middle of the cell (equatorial plane) and spindle fibres attach to them .Prophase:The nuclear envelope disapears and the centrioles migrate to opposite poles of the cellInterphase:The Cell grows and the DNA replicates. The cell prepares to divide.Anaphase:The chomatids split into new chromosomes, and the new chromosome migrate to opposite polesTelophase:The chromosomes reach the poles, new nuclei begin to form, the cell prepares to split.G1 S G2M1M2M3M4
45 Stages of Mitosis Cytokenisis Cytoplasm is split in half Each cell has identical chromosomesAnnoying Mitosis Song video
46 During your lifetime, mitosis has created the billions of cells of cells that make up your body. Mitosis is simple and nearly flawless (errors in mitosis are extremely rare)Mitosis gives each cell its own copy of all your genetic information (your DNA)Simple organisms (like the amoeba) can even reproduce by mitosis.
47 If mitosis works so well, why do we need meiosis? Sexual reproduction helps a species survive.It allows traits from two individuals to be mixed, giving greater diversity.Greater diversity gives a species a better chance of surviving hard times.
48 In order to have sexual reproduction, there must be a way of reducing chromosome numbers. You have 46 chromosome, your spouse has 46 chromosomesIf meiosis did not occur, your children would have 92 chromosomesYour grandchildren would have 184 chromosomesYour great-grandchildren 368, and so on…This would soon lead to genetic problems like birth defects or bad mutations.
49 Meiosis strips away half of the chromosomes In humans this produces eggs and sperm with only 23 chromosomes (instead of 46)Fertilization restores the chromosomesWhen a human egg is fertilized, it gets 23 chromosomes from the mother and 23 from the father, restoring the normal 46
50 Meiosis 1st Metaphase: 1st Prophase: Interphase: G1 S G2 MEIOSIS The chromosomes line up near the middle of the cell (equatorial plane) and spindle fibres attach to them .1st Prophase:The nuclear envelope disapears and the centrioles migrate to opposite poles of the cellInterphase:The Cell grows and the DNA replicates. The cell prepares to divide.G1 S G2MEIOSIS
51 Meiosis 1st Anaphase: 1st Metaphase: G1 S G2 MEIOSIS cycle 1 The WHOLE CHROMOSOMES migrate to opposite poles. They do not split yet!1st Metaphase:The chromosomes line up near the middle of the cell (equatorial plane) and spindle fibres attach to them .G1 S G2MEIOSIS cycle 11st Telophase:The chromosomes reach the poles, new nuclei begin to form, the cell prepares to split.Cytokinesis:The cell splits into two new cells
52 Meiosis Cytokinesis: Telophase: Anaphase: Prophase & Metaphase G1 S G2 The original cell has split into four new cellsTelophase:The chromosomes reach the poles, new nuclei begin to form, the cell prepares to split.Anaphase:The chomatids split into new chromosomes, and the new chromosome migrate to opposite polesProphase & MetaphaseThe chromosomes line up near the middle of the cell (equatorial plane) and spindle fibres attach to them .G1 S G2MEIOSIS cycle 2
53 Assignments on Cell Division Textbook:Read pagesTry questions 8 to 15 on page 153Workbook:Do pages 71 to 74
54 Cell Specialization No, No… Not that kind of tissue! As your cells divide they also become different from each other. They specialize.Some cells become blood cells, some become muscles, some become bone cells, and some become brain cells.A group of similar cells, with a common function, is called a tissue:No, No…Not that kind of tissue!
55 Levels of Organization Strings? make up Quarks make up Subatomic Particles make up Protons, Neutrons including Atoms make up Molecules make up Macromolecules (like DNA) make up Cell Parts make up Cells make up Tissues make up Organs make up Systems Which make up the Organisms make up Biosphere of our Planet in our Solar System in our Milky Way Galaxyin the Local Galactic Group in the Virgo Supercluster in theUniverse
56 4 Main Tissue GroupsAlthough you may have hundreds of tissue types, they all belong to four main groups of tissuesEpithelial Tissues cover and protect your body and its organs.Connective Tissues bind and support the organs and the body. They also transport oxygen and nutrients.Nerve Tissues control and guide the body, and communicate between body parts.Muscle Tissues make body movement possible
57 Epithelial Tissues Just a few of the many types of epithelial tissue: SkinStomach liningIntestinal liningArteries and veinsKidney tubules
58 Connective Tissues There are also many connective tissues, such as: Bone tissueCartilageTendons & LigamentsFatty tissuesBlood
59 Nerve Tissues Nerve tissues make up much of: The Brain The Spinal Cord The Nerves
60 Muscle Tissues There are 3 main types of muscle tissue Skeletal Muscle:The muscles attached to bone. They make movement possible.Smooth Muscle:Found inside us, smooth muscle pushes things through our organs (peristalsis).Cardiac Muscle:Found in the heart, cardiac muscle is very durable.
61 OrgansAn organ is a structure composed of two or more tissue types performing one or more specific actionsIn other words: it’s a bunch of tissues working together!Examples of Organs and their functionStomach: grinds up foodIntestine: absorbs nutrientsLungs: absorb oxygen from the airHeart: pumps bloodSkin: protects our bodies
62 Organ SystemsA system is a group of tissues working together to accomplish a common functionOur body has many systems, for example:Our cardiovascular system which circulates our blood and transports nutrients to cells.Our nervous system which controls our movements, thoughts, decisions and responsesOur reproductive system, which enables sexual reproduction
63 Examples of Organ Systems (Similar to table on page 139 of Textbook) FunctionCardiovascularCirculates blood, transports nutrients, transports wastesDigestiveBreaks down and absorbs nutrients, eliminates solid wasteEndocrineUses hormones to control organ performance.Excretory (Urinary)Eliminates the body’s liquid wastesImmuneProtects us against foreign organisms (bacteria, viruses etc.)LymphaticHelps the immune system to protect us. Drains and excess fluids from the body and filters the fluids back into the blood.MusculoskeletalProvides the body with support, mobility and protectionNervousControls the entire organism (thoughts, decisions, memories) and relays information to various body parts and interacts with the environment through the sensory organsReproductiveEnables sexual reproduction. Linked to the endocrine systemRespiratoryHelps the body absorb oxygen and expel carbon dioxide
64 Exercises on Tissues Textbook: Workbook: Read pages 136 to 139 Try question 16 to 18 on page 153Workbook:Do pages 75 and 76
66 PubertyThere are major mental and physical changes that occur during your life stagesHumans life stages:Before birth: zygoteembryofetus thenBirth: babychildadolescent adult and finally an old personPuberty occurs between childhood and adolescence
67 Puberty cont. Three categories of change occur at puberty Anatomical Shape of body fat, muscles skeletalPhysiologicalGenitals mature(external & internal)Able to procreatePsychologicalClash with authorityIdentity changeLibido (sex drive)
68 Female Reproductive System (internal organs front view) OvariesConnected to the uterus by Fallopian tubesUterusAlso called the womb.
69 Female Reproductive System (internal organs side view) Fallopian TubesOvariesUterusEndometriumUterine CervixVaginaClitoris
70 Female Reproductive System You have already learned the different partsso here’s what they doThere are two cyclesOvarian CycleEgg releaseMenstrualGetting your periodRemoves and then renews the lining of the uterus
71 Don’t mix them up!The two cycles occur at the same time, and are often confused with each other, but…They each rely on different hormonesOvarian: FSH and LHMenstrual: Estrogen and progesteroneThe Ovarian cycle has to do with releasing eggs.The Menstrual cycle has to do with preparing the uterus.Ovarian cycleMenstrual cycle
72 Ovarian cycle, egg released (around day 14)Body temperature changes slightly during cyclesHormone levels in blood change.Menstrual cycle: Thickness of the endometrium (uterus lining) grows.(from about day 6 on)Hormone spikeMenstru.Proliferation PhaseSecretory Phase
73 The ovarian cycle All ova (eggs) are produced before a girl is born The ovarian cycle is simply the release of these eggsFrom the ovariesEvery 28 days (approx.)When a woman begins to run out of eggs, Menopause may occur.The ovarian cycle stops.Then the menstrual cycle will change or stop.Many hormone changes occur.
74 Oogenesis It’s pronounced oh-oh-genesis, not ewww-genesis! Egg production begins before a woman is even born!15 to 28 weeks in utero/fetus, Oocytes (diploid junior egg cells) are produced.Then wait until puberty to be released one at a timeEach month an oocyte undergoes meiosis to become one haploid ovum (egg cell). Its three “sister eggs” die.
75 The menstrual Cycle Directly related to the ovarian cycle Vaginal bleeding occurs~Every 28 daysEndometrium (lining of uterus is discarded)The endometrium is meant toattach to fertilized eggFeed the growing fetusIf no fertilization occursBleeding, caused by loss of endometrium occurs
76 See pages 146-147 O Menstrual Cycle Ovarian Cycle DayMenstrual CycleOvarian Cycle1Bleeding, due to expulsion of endometrium and unfertilized ovum.Progesterone decreases due to deterioration of corpus luteumAn Ovarian follicle begins to mature.The Pituitary secretes FSH (Follicle Stimulating Hormone)The growing follicle secretes estrogens, which stimulates the pituitary to secrete more FSH and LH (Lutenizing Hormone)23456Endometrium Thickens.Estrogen is produced by a new ovarian follicle.7891011121314Ovulation: Follicle bursts, resulting in a surge in hormones.15Endometrium continues to thicken.Progesterone is secreted by corpus luteum .Ovarian follicle becomes the Corpus Lueteum.Corpus Luteum secretes progesterone, stopping the pituitary from releasing any more FSH and LHIf the ovum is not fertilized, the corpus luteum begins to deteriorate. It stops producing progesterone, so the pituitary starts producing FSH again16171819202122232425262728MenstruationProliferation PhaseSee pagesOSecretory Phase
77 Assignments and Exercises Text book:Read pages 143 to 148Workbook:Page 77 to 82
79 Male Reproductive System You have already learned the different partsso here’s what they doWhy do we need an erection?2 thingspenetrate/get into the vaginaDeposit sperm near the uterusWhere the egg is waiting
80 Male Reproductive System What is ejaculation?Occurs at sexual climax(most pleasure)Involuntary wave of contractions fromepididymis, through the vas deferens, prostate, seminal vesicles and finally out the urethra (know this)seminal vesicles provide 70% of the fluid in ejaculate which acts as a lunch for sperm among other things
81 What about sperm? Spermatogenesis occurs in the testicles The whole process can take up to 72 days!Starts as diploid cells in seminal tubes of, testiclesAfter meiosis they work through the middle of the tubes.All the way the epididymis6m long voyage!There they get their tails and they’re ready for actionBonus: What is a scrotum good for?Sperm coolingSperm grow optimally a 3 degrees C lower
82 Hormones Hormones are in control of: Similar to your nervous system the reproductive system development, cycles etc.Nearly all growth, and maintenance of your body systemsSimilar to your nervous systemThey communicate but the messages are slower and last much longer.
83 Hormones Produced and secreted by glands The most influential gland Male hormone gland: testiclesProduce testosteroneFemale glands: ovariesProduce estrogen and progesteroneThe most influential glandThe “gland daddy” of them allThe pituitaryBecause its hormones control sex glands and:GrowthBlood pressureSome aspects of pregnancy and childbirthBreast milk productionSex organ functions in both women and menThyroid gland functionThe conversion of food into energy (metabolism)Water and osmolarity regulation in the bodyVery Important!
84 The “Big 6” Hormones FSH Pituitary Helps initiate puberty LH Progesterone is a feedback to the pituitary, causing it to reduce the LH & FSHLong term accumulation of estrogen causes development of breasts, enlargement of hips, accumulation of fatty tissue and certain psychological changes.Then helps regulate cycles in a woman after pubertyInitiates Puberty In Both Sexes!Hormone NameSecreted byEffectsFSH(Follicle Stimulating Hormone)PituitaryHelps initiate pubertyIn female initiates follicle productionLH(Luteinizing Hormone)In female releases egg & heals follicleProgesteroneOvaries(corpus luteum)Inhibits LH & FSHThickens endometriumEstrogen(A.K.A: Oestrogen)(developing follicle)Female HormoneControls female secondary characteristics, affects endometriumTestosteroneTestesMale HormoneControls male secondary characteristicsKisspeptinHelps Initiates Puberty
85 Primary vs. Secondary sex characteristics. Affect the sex organsPrimary Sex CharacteristicsGenital organs develop and mature (M/F)Menstrual cycle starts (F)Secondary Sex CharacteristicsBreasts develop (F) Larynx enlarges (M)Pelvis widens (F) Facial hair appears (M)Fatty tissue accumulates (F) Muscles grow (M)Bone density increases (M)Pubic and underarm hair appears (both)Psychological changes occur (both)Affect other parts of the body
86 Effectiveness of Birth Control Methods “worst case” failure rates Vasectomy 1%Withdrawal* 96%Withdrawal** 27%Condom 12%Oral Contraceptive 2%Contraceptive patch 1%Injections / vaginal ring 2%Tubal ligation 1%Spermicides 21%Female condom 12%Diaphragm & spermicide 18%* As typically done** as correctly doneThe actual failure rates depend on brand and quality and the correct use of the contraceptive product. Actual failure rates may be lowerMini-pill 6%Morning after pill ??%IUD 6%
87 Assignments on Reproduction Textbook:Read pages 149 to 151Do questions 19 to 34 on pages 153 and 154WorkbookDo pages 82 to 88