Living world

Cells & Organelles

• Definition: Basic structural and functional units of all living organisms.

• Major Organelles:

  • Nucleus: Contains DNA; responsible for genetic information and gene expression.

  • Mitochondria: Energy production through ATP.; known as the powerhouse of the cell.

  • Ribosomes: Protein synthesis site; can be free-floating or attached to the endoplasmic reticulum.

  • Endoplasmic Reticulum (ER): Rough ER (with ribosomes) synthesizes proteins; Smooth ER synthesizes lipids and detoxifies.

  • Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery.

  • Lysosomes: Contains digestive enzymes to breakdown waste materials and cellular debris.

  • Cell Membrane: Semi-permeable membrane that controls the movement of substances in and out of the cell.

DNA: Structure & Function

• Structure:

  • Double Helix: Formed by two strands of nucleotides.

  • Nucleotides: Composed of a sugar, phosphate group, and nitrogenous base.

  • Base Pairing: Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

• Function:

  • Genetic Information: Contains instructions for protein synthesis.

  • Replication: DNA makes copies of itself during cell division.

Cell Division: Mitosis

• What: Process of producing two identical daughter cells from a single parent cell.

• Why: Essential for growth, repair, and asexual reproduction.

• How: Involves stages: prophase, metaphase, anaphase, and telophase.

  • Prophase: Chromatin condenses into visible chromosomes.

  • Metaphase: Chromosomes align at the cell equator.

  • Anaphase: Sister chromatids separate and move to opposite ends.

  • Telophase: Nuclear membranes form around each set of chromosomes.

Cell Division: Meiosis

• What: Specialized form of cell division that reduces chromosome number by half.

• Why: Produces gametes (sperm and eggs) for sexual reproduction.

• How: Consists of two rounds of division: Meiosis I and Meiosis II.

  • Meiosis I: Homologous chromosomes separate.

  • Meiosis II: Sister chromatids separate.

Haploid vs. Diploid

• Haploid (n): Cells with one set of chromosomes (e.g., gametes).

• Diploid (2n): Cells with two sets of chromosomes (e.g., somatic cells).

Tissues: 4 Types

• Epithelial Tissue: Covers body surfaces; involved in absorption, secretion, and protection.

• Connective Tissue: Supports, binds, and protects other tissues and organs (includes bone, blood, fat).

• Muscle Tissue: Responsible for movement (includes skeletal, cardiac, and smooth muscle).

• Nervous Tissue: Transmits impulses and processes information (neurons and glial cells).

Organs

• Definition: Structures composed of different tissues working together for specific functions. Example: The heart pumps blood.

Organ Systems (10)

• List of Organ Systems:

  • Integumentary, Muscular, Skeletal, Nervous, Endocrine, Cardiovascular, Lymphatic, Respiratory, Digestive, Urinary, Reproductive.

Puberty

Overview of Puberty

• Puberty: Preparation of the body to reproduce.

Page 1: Introduction to Puberty

• Begins as the body prepares to enter reproductive age.

Page 2: Initiation of Puberty

• Pituitary Gland:

  • Size of a grape.

  • Responsible for hormone creation.

  • Secretes hormones into the bloodstream.

• Targets the Reproductive Organs:

  • Males: Testes

    • Produce testosterone.

  • Females: Ovaries

    • Produce estrogen and progesterone.

• Key Hormones:

  • Follicle Stimulating Hormone (FSH)

  • Luteinizing Hormone (LH)

Page 3: Effects of Sex Hormones

• Males:

  • Testosterone causes:

    • Lower voice

    • Facial hair

    • Muscle and bone mass increase

    • Sperm development (primary sex characteristic)

    • Organ development and pubic hair growth.

• Females:

  • Estrogen & Progesterone cause:

    • Brain psychological changes

    • Breast development

    • Hair growth

    • Egg development (primary sex characteristic)

    • Menstruation begins

    • Organ development and pubic hair growth

    • Widening of hips.

Page 4: Female Summary of Puberty Changes

• Hormones Secreted by the Pituitary Gland:

  • Follicle Stimulating Hormone (FSH)

  • Luteinizing Hormone (LH)

• Effects of Female Sex Hormones:

  • Psychological changes in the brain.

  • Secondary sexual characteristics include:

    • Breast development

    • Underarm hair and pubic hair growth

    • Menstrual cycle begins

    • Pelvis widens

    • Fatty tissue accumulates (hips and breasts).

Page 5: Male Summary of Puberty Changes

• Hormones Secreted by the Pituitary Gland:

  • Follicle Stimulating Hormone (FSH)

  • Luteinizing Hormone (LH)

• Effects of Male Sex Hormones (Testosterone):

  • Psychological changes in the brain.

  • Secondary sexual characteristics include:

    • Facial hair (beard and moustache)

    • Voice deepening

    • Muscle growth and increased bone density

    • Underarm hair and general hairiness increase

    • Pubic hair and genital organs develop

    • Appearance of testicles.

Female Reproductive System

• Oogenesis

  • The process of creating an egg (ovum) using meiosis.

• Ovarian Cycle

  • Involves maturation of a follicle and release of an egg, which leaves behind a corpus luteum.

• Menstrual Cycle

  • Refers to the changes in the uterine endometrium

Basic Anatomy

• Key Structures:a) Vaginab) Cervixc) Uterusd) Ovarye) Fallopian Tube

• Associated Organs:

  1. Bladder (part of the urinary system)

  2. Urethra (part of the urinary system)

  3. Rectum (part of the digestive system)

Ovarian Cycle

• Day 1-28:

  • Hormonal dynamics involve significant physiological changes in response to follicle development and corpus luteum function.

• Ovarian Cycle Phases:

  • Ovarian Cycle Definition

    The ovarian cycle refers to the monthly hormonal changes and physiological processes that take place in a woman's ovaries, culminating in the maturation and release of an egg (ovum). It involves two main phases: the follicular phase and the luteal phase, alongside the event of ovulation that separates them.

    Phases of the Ovarian Cycle

    1. Follicular Phase

       • Duration: This phase begins on Day 1 of the menstrual cycle and typically lasts about 14 days.

       • Hormonal Regulation: The Follicle Stimulating Hormone (FSH) stimulates the growth and maturation of ovarian follicles. As the dominant follicle matures, it produces estrogen, which plays a critical role in thickening the endometrial lining in preparation for a potential pregnancy.

       • Follicle Development: Multiple follicles may start to develop, but usually, only one follicle becomes dominant and reaches maturity, while the others regress.

    2. Ovulation

       • Timing: Ovulation occurs approximately on Day 14 of a typical cycle, triggered by a surge in Luteinizing Hormone (LH) that results from increased estrogen levels.

       • Process: The mature follicle releases the egg from the ovary into the fallopian tube, where fertilization can occur if sperm is present

         3. Luteal Phase

       • Duration: This phase lasts from ovulation until the start of menstruation, roughly 14 days.

       • Hormonal Changes: After the egg is released, the ruptured follicle transforms into the corpus luteum, which secretes progesterone and estrogen. These hormones maintain the endometrial lining and prepare the uterus for potential implantation of a fertilized egg.

       • Outcome: If fertilization does not occur, the corpus luteum degenerates, leading to decreased hormone levels, and ultimately, the shedding of the endometrial lining (menstruation) signifies the start of a new cycle.

       • Menstrual Cycle

  • Menstrual Cycle Overview

    • The menstrual cycle typically lasts 28 days and includes three primary phases with distinct events and hormonal changes.

    1. Menstrual Phase (Days 1 to 5)

    • Event: Bleeding occurs.

      • Caused by the expulsion of the endometrium and unfertilized ovum.

    • Hormones: Production of progesterone decreases.

      • This decrease is due to the deterioration of the corpus luteum.

    2. Proliferation Phase (Days 6 to 14)

    • Event: Endometrium begins to thicken.

    • Hormones: Production of estrogens increases.

      • This is due to activity from a new ovarian follicle.

    3. Secretory Phase (Days 15 to 28)

    • Event: Endometrium continues to thicken.

    • Hormones: Secretion of progesterone increases.

      • This secretion is carried out by the corpus luteum.

    Summary of Key Terms

    • FSH (Follicle Stimulating Hormone): Hormone that stimulates the maturation of ovarian follicles.

    • LH (Luteinizing Hormone): Hormone that triggers ovulation and the formation of the corpus luteum.

    • Corpus Luteum: Structure formed from the remains of the follicle after ovulation, crucial for hormone production in the luteal phase.

    The ovarian cycle is a vital aspect of female reproductive health, playing a significant role in fertility and overall hormonal balance.

Hormonal Influences on Mood and Symptoms

• Hormonal Imbalances:

  • Changing levels of hormones can create varying imbalances affecting individuals differently.

• Mood & Energy:

  • Estrogen: Linked to serotonin, enhancing mood.

  • FSH: Linked to estradiol, helping to limit stress hormones.

  • LH: Increased testosterone leads to higher energy levels.

  • Progesterone: Can increase irritability by elevating stress hormones (cortisol).

• Physical Symptoms:

  • Estrogen and Progesterone can lead to increased bodily retention of salt and water, causing bloating, cramping, and gas.

  • They can also interfere with neurochemicals, resulting in headaches.

  • Loss of uterine lining from decreased progesterone can trigger immune responses causing nausea and further headaches.

Male Reproductive System

Male Reproductive System Overview

• FSH (Follicle Stimulating Hormone) from the pituitary gland triggers the testicles to produce testosterone and initiate spermatogenesis.

• Spermatogenesis: Spermatogenesis is the process by which spermatozoa, or mature sperm cells, are produced from spermatogonia (diploid cells) in the testicles. This process is crucial for male fertility and occurs within the seminiferous tubules. sperm cells, are produced from spermatogonia (diploid cells) in the testicles. This process is crucial for male fertility and occurs within the seminiferous tubules.

• Ejaculation: expulsion of semen by the penis

• Erection: involves the increase in volume and rigidity of a penis as a result of sexual arousal

Basic Anatomy of the Male Reproductive System

• Penis: External organ that delivers sperm.

• Testicle: Organs that produce sperm and testosterone.

• Scrotum: Sac that holds the testicles and maintains optimal temperature for sperm production.

• Urethra: Tube that transports semen and urine out of the body.

• Prostate: gland that produces seminal fluid, contributing to semen.

• Seminal duct: transport tube for semen from the seminal vesicles.

• Vas deferens: tube that carries sperm from the epididymis to the ejaculatory duct.

• Epididymis: coiled tube where sperm mature.

• Seminiferous tubules: site of sperm production inside the testicles.

Spermatogenesis Process

1. Location: Spermatogenesis occurs in the seminiferous tubules.

2. Stages:

   • Spermatogonium: A diploid cell (2n) that undergoes meiosis.

   • Haploid Cell: Result from meiosis, becomes more specialized.

   • Spermatozoa: Mature sperm through a series of transformations.

Delivery of Sperm

1. Completion of spermatogenesis results in formation of sperm.

2. Sperm combines with seminal fluid to form semen.

3. The prostate adds nutrients to the semen (appearance - white).

4. Sperm exits through the penis during ejaculation.

Contraceptive Methods Comparison (Male vs. Female)