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Chapter 5 The human organism and the perpetuation of life.

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1 Chapter 5 The human organism and the perpetuation of life.
Topics: The cell and its functions Cell division (mitosis & meiosis) Tissues, organs and systems The Reproductive System

2 About Cells The cell is the basic unit of structure and function in living things Cells 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 cells Protozoans contain a single cell Humans contain billions of cells

3 CELL PARTS The 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 that Macromolecules, 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 membrane The Cytoplasm & Organelles The nucleus & Chromosomes Membrane Cytoplasm (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 environment Forms a protective barrier Helps absorb nutrients and useful substances Helps 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 protoplasm The cytoplasm is the liquid portion of the cell. It is a complex mixture of materials: water, gases, wastes, nutrients, raw materials The Organelles Suspended in the cytoplasm are many tiny structures called organelles. Each organelle has a specific function.

8 The Organelles Mitochondria (sing. mitochondrion).
Endoplasmic reticulum Rough Smooth Ribosomes Golgi Apparatus Lysosomes Vacuoles

9 Mitochondria The 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 cell Rough ER Has ribosomes Smooth ER Has no ribosomes ER Transport system at your service! For when it absolutely, positively has to get to the ribosomes quick as possible.

11 Ribosomes Very tiny, round organelles associated with protein synthesis They 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 ER Its purpose is to modify and “package” proteins that will be secreted. Also makes digestive enzymes I look like sort of like a stack of pancakes with blobs of syrup falling off!

13 I’ve got the digestive enzymes
Lysosomes & Vacuoles These are storage areas within a cell Lysosomes hold digestive enzymes that help the cell metabolize food. When a cell dies, the digestive enzymes help dissolve the dead cell Vacuoles store food or water Let’s get together And have a feast! I’ve got the digestive enzymes And I’ve got the food

14 All the organelles get their instructions from me.
Part 3: The Nucleus The nucleus consists of: The nuclear membrane or envelope (with tiny nuclear pores in it) The nucleoplasm The chromatin material AKA chromosomes The nucleolus Hey! I am, like, in control, man! All the organelles get their instructions from me.

15 Exercise Colour, label and give the functions of the cell drawing.

16 Typical Human Cell

17 Cell Membrane Smooth ER Cytoplasm Mitochondrion Ribosome Nucleus Golgi apparatus Lysosome Endocytosis / Exocytosis Nucleoplasm or “matrix” (containing chromatin) Nucleolus Nuclear membrane “envelope” (with nuclear pores in it) Rough ER

18 DNA a helix is a spiral shape, similar to a spring. DNA is a molecule, shaped like a double helix, usually found inside the cell’s nucleus. Facts about DNA Chromosomes are made of DNA Genetic information is stored on DNA DNA 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) Hydrogen atom (white) Phosphorus atom (orange) Oxygen atom (red) Nitrogen Atom (blue) Portion of a Model of a DNA Molecule Simplified drawing of a DNA Molecule DNA contains carbon, hydrogen, oxygen, nitrogen and phosphorus The 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 Genes A 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 Diversity Genetic 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. 152 Workbook Do pages 67 to 70

24 Topics: Mitosis Overview Meiosis Overview Mitosis vs. Meiosis
Mitosis & Meiosis Topics: Mitosis Overview Meiosis Overview Mitosis 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 again OR Cell Dies

26 Overview of Mitosis Interphase Prophase Cytokinesis Metaphase
Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming

27 2 Main Events of the Cell Cycle
Interphase: Cell grows & prepares for Mitosis (see previous slide for diagram) Prepares 2 ways Replicates chromosomes “Tools” for mitosis are produced Mitosis: Cell divides to form two genetically identical cells One 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 diploid One 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

29 Meiosis

30 Meiosis main points Meiosis Enables sexual reproduction
Starts with diploid cells Two 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 cycle The Rest of the CELL CYCLE Cell Division (MITOSIS)

32 Phases in the Cell Cycle
M A T Remember: = INTERPHASE Preparing for Mitosis Where’s my Pee MAT? It will help you keep track of the 5 main phases of a cell’s life = PROPHASE Undergoing Mitosis = METAPHASE = ANAPHASE = TELOPHASE (and cytokinesis)

33 The Cell Cycle Cytokinesis: Metaphase: Prophase: Interphase: Anaphase:
The cell splits into two new cells Metaphase: 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 cell Interphase: 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 poles Telophase: The chromosomes reach the poles, new nuclei begin to form, the cell prepares to split. G1 S G2 M1 M2 M3 M4

34 Mitosis: Short video

35 Interphase Interphase: Cell prep for mitosis (G1, S, G2)
Cell spends ~94% of life in interphase

36 Photograph of Interphase

37 Stages of Mitosis Prophase: (Prep Phase)
Chromosomes coil and become visible Nuclear membrane breaks down Spindle fibers assemble

38 Photo: Early Prophase Chromosomes

39 Stages of Mitosis Metaphase (Middle)
Chromosomes line up in the middle of cell Spindle fibers bind to the centromere

40 Photo: Metaphase Spindle (fibers) Centrosome Chromosomes
Equatorial Plane

41 Stages of Mitosis Anaphase (Apart)
Spindle fibers pull chromosomes to opposite sides of the cell

42 Photo: Anaphase Centrosome Chromosomes Equatorial Plane

43 Stages of Mitosis Telophase (Two) Cell begins to split into two cells
Nuclear membranes reform

44 Photo: Telophase & Cytokinesis
Cleavage furrow Nucleus forming Cells Divide

45 Stages of Mitosis Cytokenisis Cytoplasm is split in half
Each cell has identical chromosomes Annoying 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 chromosomes If meiosis did not occur, your children would have 92 chromosomes Your grandchildren would have 184 chromosomes Your 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 chromosomes When 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 cell Interphase: The Cell grows and the DNA replicates. The cell prepares to divide. G1 S G2 MEIOSIS

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 G2 MEIOSIS cycle 1 1st 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 cells Telophase: 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 poles Prophase & Metaphase The chromosomes line up near the middle of the cell (equatorial plane) and spindle fibres attach to them . G1 S G2 MEIOSIS cycle 2

53 Assignments on Cell Division
Textbook: Read pages Try questions 8 to 15 on page 153 Workbook: 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 Galaxy in the Local Galactic Group  in the  Virgo Supercluster in theUniverse

56 4 Main Tissue Groups Although you may have hundreds of tissue types, they all belong to four main groups of tissues Epithelial 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:
Skin Stomach lining Intestinal lining Arteries and veins Kidney tubules

58 Connective Tissues There are also many connective tissues, such as:
Bone tissue Cartilage Tendons & Ligaments Fatty tissues Blood

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 Organs An organ is a structure composed of two or more tissue types performing one or more specific actions In other words: it’s a bunch of tissues working together! Examples of Organs and their function Stomach: grinds up food Intestine: absorbs nutrients Lungs: absorb oxygen from the air Heart: pumps blood Skin: protects our bodies

62 Organ Systems A system is a group of tissues working together to accomplish a common function Our 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 responses Our reproductive system, which enables sexual reproduction

63 Examples of Organ Systems (Similar to table on page 139 of Textbook)
Function Cardiovascular Circulates blood, transports nutrients, transports wastes Digestive Breaks down and absorbs nutrients, eliminates solid waste Endocrine Uses hormones to control organ performance. Excretory (Urinary) Eliminates the body’s liquid wastes Immune Protects us against foreign organisms (bacteria, viruses etc.) Lymphatic Helps the immune system to protect us. Drains and excess fluids from the body and filters the fluids back into the blood. Musculoskeletal Provides the body with support, mobility and protection Nervous Controls the entire organism (thoughts, decisions, memories) and relays information to various body parts and interacts with the environment through the sensory organs Reproductive Enables sexual reproduction. Linked to the endocrine system Respiratory Helps 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 153 Workbook: Do pages 75 and 76

65 Reproductive Systems Puberty Female: Menstrual & Ovarian Cycles
Male: Erection & Ejaculation Hormones

66 Puberty There are major mental and physical changes that occur during your life stages Humans life stages: Before birth: zygoteembryofetus then Birth: babychildadolescent adult and finally an old person Puberty occurs between childhood and adolescence

67 Puberty cont. Three categories of change occur at puberty Anatomical
Shape of body fat, muscles skeletal Physiological Genitals mature (external & internal) Able to procreate Psychological Clash with authority Identity change Libido (sex drive)

68 Female Reproductive System (internal organs front view)
Ovaries Connected to the uterus by Fallopian tubes Uterus Also called the womb.

69 Female Reproductive System (internal organs side view)
Fallopian Tubes Ovaries Uterus Endometrium Uterine Cervix Vagina Clitoris

70 Female Reproductive System
You have already learned the different parts so here’s what they do There are two cycles Ovarian Cycle Egg release Menstrual Getting your period Removes 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 hormones Ovarian: FSH and LH Menstrual: Estrogen and progesterone The Ovarian cycle has to do with releasing eggs. The Menstrual cycle has to do with preparing the uterus. Ovarian cycle Menstrual cycle

72 Ovarian cycle, egg released
(around day 14) Body temperature changes slightly during cycles Hormone levels in blood change. Menstrual cycle: Thickness of the endometrium (uterus lining) grows. (from about day 6 on) Hormone spike Menstru. Proliferation Phase Secretory Phase

73 The ovarian cycle All ova (eggs) are produced before a girl is born
The ovarian cycle is simply the release of these eggs From the ovaries Every 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 time Each 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 days Endometrium (lining of uterus is discarded) The endometrium is meant to attach to fertilized egg Feed the growing fetus If no fertilization occurs Bleeding, caused by loss of endometrium occurs

76 See pages 146-147 O Menstrual Cycle Ovarian Cycle
Day Menstrual Cycle Ovarian Cycle 1 Bleeding, due to expulsion of endometrium and unfertilized ovum. Progesterone decreases due to deterioration of corpus luteum An 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) 2 3 4 5 6 Endometrium Thickens. Estrogen is produced by a new ovarian follicle. 7 8 9 10 11 12 13 14 Ovulation: Follicle bursts, resulting in a surge in hormones. 15 Endometrium 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 LH If the ovum is not fertilized, the corpus luteum begins to deteriorate. It stops producing progesterone, so the pituitary starts producing FSH again 16 17 18 19 20 21 22 23 24 25 26 27 28 Menstruation Proliferation Phase See pages O Secretory Phase

77 Assignments and Exercises
Text book: Read pages 143 to 148 Workbook: Page 77 to 82

78 Male Reproductive System Reference page 149

79 Male Reproductive System
You have already learned the different parts so here’s what they do Why do we need an erection? 2 things penetrate/get into the vagina Deposit sperm near the uterus Where the egg is waiting

80 Male Reproductive System
What is ejaculation? Occurs at sexual climax (most pleasure) Involuntary wave of contractions from epididymis, 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, testicles After meiosis they work through the middle of the tubes. All the way the epididymis 6m long voyage! There they get their tails and they’re ready for action Bonus: What is a scrotum good for? Sperm cooling Sperm 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 systems Similar to your nervous system They communicate but the messages are slower and last much longer.

83 Hormones Produced and secreted by glands The most influential gland
Male hormone gland: testicles Produce testosterone Female glands: ovaries Produce estrogen and progesterone The most influential gland The “gland daddy” of them all The pituitary Because its hormones control sex glands and: Growth Blood pressure Some aspects of pregnancy and childbirth Breast milk production Sex organ functions in both women and men Thyroid gland function The conversion of food into energy (metabolism) Water and osmolarity regulation in the body Very 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 & FSH Long 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 puberty Initiates Puberty In Both Sexes! Hormone Name Secreted by Effects FSH (Follicle Stimulating Hormone) Pituitary Helps initiate puberty In female initiates follicle production LH (Luteinizing Hormone) In female releases egg & heals follicle Progesterone Ovaries (corpus luteum) Inhibits LH & FSH Thickens endometrium Estrogen (A.K.A: Oestrogen) (developing follicle) Female Hormone Controls female secondary characteristics, affects endometrium Testosterone Testes Male Hormone Controls male secondary characteristics Kisspeptin Helps Initiates Puberty

85 Primary vs. Secondary sex characteristics.
Affect the sex organs Primary Sex Characteristics Genital organs develop and mature (M/F) Menstrual cycle starts (F) Secondary Sex Characteristics Breasts 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 done The actual failure rates depend on brand and quality and the correct use of the contraceptive product. Actual failure rates may be lower Mini-pill 6% Morning after pill ??% IUD 6%

87 Assignments on Reproduction
Textbook: Read pages 149 to 151 Do questions 19 to 34 on pages 153 and 154 Workbook Do pages 82 to 88


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