FIINAL EXAM

Fundamentals of Anatomy and Physiology

• Anatomy: The study of the structure of living organisms.

• Physiology: The study of the function of the body's systems.

Ways to Study Anatomy:

• Inspection: Looking at the body’s surface.

• Palpation: Feeling structures with the hands.

• Auscultation: Listening to body sounds.

• Percussion: Tapping and listening for abnormalities.

• Dissection: Cutting and separating tissues.

• Comparative Anatomy: Studying and comparing other species.

• Medical Imaging: Viewing inside the body without surgery (e.g., CT, MRI, PET scans).

• Gross Anatomy: Studying structures visible to the naked eye.

• Histology: Microscopic study of tissues.

• Cytology: The study of individual cells.

• Ultrastructure: Viewing molecular-level detail via electron microscopy.

The Scientific Method and Research Principles

• Scientific Method: A systematic approach to gaining knowledge through observation, testing, and reasoning.

• Hypothesis: An educated guess or testable explanation.

• Sample Size: Number of subjects in a study; larger sizes increase reliability.

• Controls (Control Group): Subjects not receiving experimental treatment for comparison.

• Treatment Group: Subjects receiving the experimental condition.

• Psychosomatic Effects: Effects caused by the subject’s expectations.

• Placebo: A substance with no physiological effect, used to control for psychosomatic effects.

• Experimenter Bias: When a researcher’s expectations influence results.

• Double-Blind Method: Neither subjects nor experimenters know who is receiving treatment to prevent bias.

• Statistical Testing: Determines if results are due to treatment or random chance.

• Peer Review: Evaluation of research by experts before publication for quality assurance.

• Law of Nature: Generalizations of predictable behaviors of matter and energy.

• Theory: A summary of conclusions from repeated observations explaining phenomena.

Hierarchy of Complexity and Levels of Organization

• Hierarchy of Complexity:

  • Atom: Smallest unit of matter.

  • Molecule: Two or more atoms.

  • Organelle: A cell structure with a specific function.

  • Cell: The smallest living unit.

  • Tissue: A group of similar cells.

  • Organ: Two or more tissues working together.

  • Organ System: A group of organs with a shared function.

  • Organism: One complete individual.

  • Eponyms: Terms named after people.

Chemical Level of Organization:

• Chemical Study: Substances and reactions essential for life.

• Atoms Example: Sodium (Na), Potassium (K), Calcium (Ca).

• Molecules, Compounds, Macromolecules: Examples include Proteins, Lipids, and Carbohydrates.

Human Body Systems and Components

• Integumentary System: Covers and protects; includes skin, hair, nails, glands.

• Skeletal System: Provides structural support; includes bones, joints, cartilage, ligaments.

• Muscular System: Internal and external movement; includes tendons, muscles.

• Nervous System: Controls all body functions; includes brain, spinal cord, nerves.

• Endocrine System: Glands releasing hormones; includes pituitary, thyroid, adrenal glands, ovaries, testes.

• Cardiovascular System: Supplies oxygen/nutrients and removes waste through blood; includes heart, blood vessels.

• Lymphatic System: Immune system and fluid transport; includes thymus, spleen, lymph nodes.

• Respiratory System: Expels CO₂; includes lungs, nasal cavity.

• Digestive System: Breaks down food, absorbs nutrition, removes waste; includes stomach, liver, intestines.

• Urinary System: Filters blood, eliminates waste; includes kidneys, bladder.

• Reproductive System: Produces offspring; includes gonads, mammary glands.

Anatomical Positions and Directional Terminology

• Anatomical Position:

  • Supine: Lying on back.

  • Prone: Lying on belly.

Directional Terms:

• Superior: Above.

• Inferior: Below.

• Rostral: Towards the face.

• Caudal: Towards the back of the head.

• Contralateral: Opposite side.

• Ipsilateral: Same side.

• Anterior: Front of the body.

• Ventral: Back side (typically anterior in humans).

• Posterior: The rear.

• Dorsal: The back.

• Medial: Towards the midline.

• Lateral: Away from the midline.

• Proximal: Closer to the point of attachment.

• Distal: Further from the point of attachment.

• Superficial: Closer to the surface.

• Deep: Further from the surface.

Regional Terminology:

• Axial: Center of the body; includes skull, spine.

• Appendicular: The limbs; includes arms, legs.

Planes and Sections:

• Midsagittal: Equal right and left parts.

• Sagittal: Unequal right and left parts.

• Transverse: Horizontal separation into upper and lower parts.

• Coronal: Vertical separation into front and back parts.

Body Cavities and Homeostasis

• Ventral Cavity: Fluid-filled space around organs; includes thoracic (heart, lungs), abdominal (digestive organs), pelvic (bladder, reproductive organs).

• Cranial Cavity: Houses the brain.

• Vertebral Cavity: Houses the spinal cord.

• Homeostasis: Regulation of internal environment.

• Feedback Loop: Monitors changes in the body.

  • Receptor: Monitors changes.

  • Integrator: Processes information for responses.

  • Effector: Corrects changes.

• Negative Feedback: Resists deviation from a set point.

• Positive Feedback: Changes status instead of restoring homeostasis.

Atomic Structure and Chemical Bases of Life

• Nucleus: Center of the atom.

• Protons: Positive charge, defines element.

• Neutrons: No charge, provides stability.

• Electrons: Negative charge, orbit nucleus.

• Valence Electrons: Outermost electrons for bonding.

• Isotope: Forms of the same element with different neutrons.

• Major Elements: Essential for life (O, C, H, N, Ca, P).

• Trace Elements: Needed in small amounts (Na, K, Fe).

• Ions:

  • Anion: Negative charge (extra electron).

  • Cation: Positive charge (loss of electron).

• Electrolytes: Ionize in water; conduct electrical currents (Na, Cl, Ca, K).

• Free Radicals: Unstable particles that can cause damage like cancer, aging and death of heart tissue

• Antioxidants: Neutralize free radicals.

Chemical Bonds and Molecules

• Molecules: Composed of two or more atoms.

• Compounds: Composed of different elements.

• Molecular Formula: Identifies elements and atom counts.

• Chemical Bonds:

  • Ionic: Attraction between ions.

  • Covalent: Sharing of electrons.

  • Polar Covalent: Unequal sharing.

  • Nonpolar Covalent: Equal sharing.

  • Hydrogen Bonds: Weak attraction between molecules.

  • Van der Waals Forces: Brief attractions between neutral atoms.

Water Properties and pH

• Water Characteristics:

  • Polarity: Water is a polar molecule.

  • Solvency: Can dissolve other chemicals.

  • Cohesion: Like molecules cling together.

  • Adhesion: Different substances cling together.

  • Chemical Reactivity: Undergoes changes.

  • Thermal Stability: Stabilizes body temperature.

• Hydrophobic: Repellent to water (e.g., oil).

• Hydrophilic: Attracted to water (e.g., sugar).

• Dehydration Synthesis: Links monomers.

• Hydrolysis: Breaks polymers into monomers.

• pH Scale: Measures hydrogen ions in solutions.

  • Acid: Proton donor; pH 0-7.

  • Alkaline (Base): Proton acceptor; pH 8-14.

  • Neutral: pH of 7.

  • Buffers: Resist pH change.

  • Acidosis: Fluids become acidic.

  • Alkalosis: Blood pH rises above 7.

Organic Chemistry and Macromolecules

• Organic Molecules: Contain carbon.

• Inorganic Molecules: Lack carbon but have hydrogen.

• Macromolecules: Large, complex molecules.

• Carbon: Four valence electrons for bonding.

• Functional Group: Clusters of atoms attached to a carbon chain.

• Polymers: Series of similar monomers.

• Monomer: A small molecule forming a larger one.

• Polymerization: Joining monomers into a polymer.

Carbohydrates:

• Monomers: Monosaccharides (e.g., Glucose, Fructose).

• Polymers: Polysaccharides (e.g., Glycogen, Starch).

• Function: Energy supply via ATP.

Proteins:

• Monomers: Amino Acids (e.g., Methionine, Glycine).

• Polymers: Polypeptides.

• Shapes and Functions: Include Collagen (structural), Hemoglobin (oxygen transport), Enzymes (catalysts).

Lipids:

• Monomers: Fatty acids, Steroids.

• Polymers: Triglycerides, HDL, LDL.

• Function: Used for energy/storage.

Nucleic Acids:

• Macromolecules: DNA and RNA composed of nucleotides (Sugar, Phosphate, Nitrogen base).

Cell Theory and Structure

• Cell Theory Principles:

  • All organisms are made of cells.

  • The cell is the simplest life unit.

  • Biogenesis: cells arise from existing cells.

  • Structure/function relate to cell activities.

• Cell Size/Resolution: Human eye ~0.1 mm.

• Cell Structure Components:

  • Plasma Membrane: Semipermeable barrier; lipid-based composition.

  • Cytoplasm: Fluid containing organelles.

  • Extracellular Fluid: Fluid outside cells.

Organelles and Their Functions

• Nucleus: Control center; stores DNA.

• Endoplasmic Reticulum (ER):

  • Rough ER: Produces proteins.

  • Smooth ER: Lipid metabolism/detoxification.

• Golgi Complex: Modifies, packages, ships proteins.

• Mitochondria: Powerhouse; produces ATP.

• Lysosome: Digestive enzymes for waste breakdown.

• Ribosomes: Protein synthesis.

• Peroxisomes: Detoxification.

• Cytoskeleton: Provides structure and movement.

• Centrosome/Centrioles: Cell division/microtubule organization.

Cell Cycle and Genetics

• The Cell Cycle:

  • G1 Phase: Cell growth.

  • S Phase: DNA replication.

  • G2 Phase: Growth/preparation for division.

  • M+C Phase: Mitosis and cytokinesis.

• Stem Cells: New cell production.

• Cancer-Related Genetics:

  • HER2: Stimulates growth; excess in breast cancer.

  • BRCA Genes: DNA repair; mutations increase cancer risk.

• Genetics and Inheritance:

  • Gametes: 23 chromosomes from each parent.

  • Alleles: Different gene versions.

  • Genome: Total gene collection (25,000–35,000).

  • Coding vs. Noncoding DNA: 2% coding, 98% noncoding (“junk” DNA).

DNA and RNA Structure

• DNA:

  • Diameter: 2 nm; double helix structure.

  • Nucleotides: Deoxyribose sugar, Phosphate, Nitrogenous bases.

  • Law of Complementary Base Pairing: A-T, C-G.

Chromatin:

• Filamentous DNA/protein structure; organized into nucleosomes.

RNA:

• Single-stranded; shorter than DNA; components: Ribose sugar, Phosphate, Nitrogenous bases (A, G, C, U).

• Types: mRNA, rRNA, tRNA.

Protein Synthesis Mechanics

• Central Dogma: DNA → mRNA → Protein.

• Transcription: DNA to mRNA in the nucleus.

• Translation: mRNA to proteins in the cytoplasm.

• Genetic Code:

  • Base Triplet: 3 nucleotides on DNA.

  • Codon: 3 nucleotides on mRNA coding for an amino acid.

  • Start Codon: AUG (Methionine).

  • Stop Codons: UAG, UGA, UAA.

• Ribosomal Sites: P (peptidyl), A (acceptor), E (exit).

Questions & Discussion (Genetics)

• Question: What’s the DNA sequence across from ATTGACTCG?

  • Answer: Complementary strand is TAACTGAGC.

• Question: DNA with 20% adenine, what’s cytosine percentage?

  • Answer: If A = 20%, then T = 20%. C + G = 60% (C = G); %C = 30%.

Integumentary System

• Components: Skin, nails, hair, glands.

• Functions: Protection, sensation, temperature regulation, Vitamin D synthesis.

• Skin Layers:

  • Epidermis: Superficial epithelial tissue.

  1. Stratum Corneum: Outermost layer.

  2. Stratum Lucidum: Only in thick skin.

  3. Stratum Granulosum: Start of keratin production.

  4. Stratum Spinosum.

  5. Stratum Basale: Bottom layer.

  • Dermis: Deeper connective tissue; includes papillary and reticular layers.

  • Hypodermis: Subcutaneous layer of fat.

• Cells of the Epidermis:

  • Keratinocytes: Produce keratin.

  • Melanocytes: Produce melanin.

  • Dendritic/Langerhans cells: Immune function.

  • Tactile/Merkel cells: Sensory function.

  • Stem cells: Regeneration.

• Temperature Regulation:

  • Vasodilation: Blood vessels widen to lose heat.

  • Vasoconstriction: Blood vessels shrink to conserve heat.

Glands:

• Merocrine: Standard sweat glands.

• Apocrine: Sweat with fatty acids; causes body odor.

• Sebaceous: Oil secretion.

• Ceruminous: Ear wax secretion.

• Mammary (Holocrine): Milk production.

Skin Cancer Types:

• Basal cell (most common), Squamous cell, Malignant melanoma (most deadly).

• ABCD Rules: Asymmetry, Border, Color, Diameter, Evolving.

Burns:

• Degree Measures:

  • 1st Degree: Epidermis only.

  • 2nd Degree: Dermis (partial thickness).

  • 3rd Degree: Tissue, muscle, bone (full thickness).

• Grafts: Autograft (self), Isograft (twin), Allograft (other human), Xenograft (other species).

Histology: The Study of Tissues

• Four Main Classes of Tissues:

  • Epithelial Tissue: Layers of closely adhering cells.

  • Connective Tissue (CT): Abundant, provides support, protection, energy storage.

  • Muscular Tissue: Facilitates movement.

  • Nervous Tissue: Conducts impulses.

• Embryonic Germ Layers:

  • Ectoderm: Epidermis and nervous system.

  • Endoderm: GI tract and respiratory lining.

  • Mesoderm: Muscle, bone, blood.

• Epithelial Types:

  • Simple Squamous: Flat; rapid diffusion.

  • Simple Cuboidal: Absorption, secretion.

  • Simple Columnar: Absorption and secretion.

  • Pseudostratified: Appears multilayered but is one layer.

  • Stratified Squamous: Keratinized vs. Nonkeratinized.

  • Transitional: Allows stretching.

Connective Tissue Elements:

• Ground substance: Components like GAGs, proteoglycans.

• Fibers: Collagen, Elastic, Reticular.

• Cells: Fibroblasts, WBCs, Macrophages, Plasma cells, Mast cells, Adipocytes.

• Cartilage Types: Hyaline (joint movement), Elastic (support), Fibrocartilage (shock absorption).

Osseous Tissue and the Skeletal System

• Osteology: Study of bone tissue.

• Bone Functions: Support, protection, movement, electrolyte balance, blood formation.

• Bone Classification: Long (humerus), Short (carpal), Flat (skull), Irregular (vertebrae).

• Long Bone Anatomy: Diaphysis (shaft), Epiphyses (heads), Articular cartilage, Medullary cavity, Periosteum.

• Osseous Histology:

  • Osteogenic Cells: Stem cells.

  • Osteoblasts: Bone-forming cells.

  • Osteocytes: mature bone cells

  • Osteoclasts: Bone-dissolving cells.

• Bone Matrix: 2/3 inorganic (e.g., Hydroxyapatite), 1/3 organic (collagen).

• Bone Structures: Osteon, Central canal, Trabeculae (in spongy bone).

• Mineral Disorders: Rickets (childhood), Osteomalacia (adults), Osteogenesis Imperfecta (collagen defect).

• Hormones in Calcium Homeostasis: Calcitriol (raises), Calcitonin (lowers), PTH (raises).

• Osteoporosis: Loss of bone mass; brittle bones.

Arthrology: The Study of Jointsbefore

• Functional Classification:

  • Synarthrosis: Little to no movement.

  • Amphiarthrosis: Slightly movable.

  • Diarthrosis: Freely movable.

• Structural Classification:

  • Bony Joints: Two fused bones.

  • Fibrous Joints: Held by collagen.

  • Cartilaginous Joints: Linked by cartilage.

  • Synovial Joints: Feature a joint cavity.

• Synovial Joint Types:

  1. Ball-and-Socket: Multiaxial (shoulder, hip).

  2. Condyloid: Biaxial (wrist).

  3. Saddle: Biaxial (thumb).

  4. Gliding/Plane: Biaxial (carpals).

  5. Hinge: Monaxial (elbow, knee).

  6. Pivot: Monaxial (neck).

Movement Terminology:

• Abduction (away), Adduction (toward), Flexion (decrease angle), Extension (increase angle), Supination, Pronation.

Muscular Tissue and Nerve Relationships

• Muscle Cells Characteristics: Responsiveness, Conductivity, Contractility, Extensibility, Elasticity.

• Skeletal Muscle Structure: Voluntary striated; fiber length $3$--$30$ cm; diameter $100 ext{ }oldsymbol{ ext{μ}}$m.

• Connective Tissue Envelopes: Endomysium, Perimysium, Epimysium.

• Myofilaments:

  • Thick Filaments: Myosin molecules.

  • Thin Filaments: Actin strands with regulatory proteins.

• Sarcomere: Contractile unit from Z disc to Z disc.

• Neuromuscular Junction (NMJ): Synapse between nerve and muscle; uses ACh.

• Contraction Mechanism:

  1. ACh release and excitation.

  2. Calcium release from SR.

  3. Calcium binds to troponin; tropomyosin shifts.

  4. Cross-bridge formation and power stroke.

• Rigor Mortis: Stiffening 3 to 4 hours post-death due to lack of ATP.

• Length-Tension Relationship: Optimal resting length yields highest force.

Body Fluid and Acid-Base Balance

• Body Fluid Distribution: Total Body Weight ($TBW$) is $60 ext{%}$ fluid; distribution: Intracellular ($16 ext{%}$), Extracellular ($4 ext{%}$), Interstitial ($40 ext{%}$).

• Water Exchange Factors: Capillary blood pressure, plasma colloid osmotic pressure, etc.

• Edema: Water accumulation.

• Water Regulation:

  • Intake: Hypothalamic osmoreceptors detect osmolarity.

  • Output: ADH promotes retention; ANF inhibits reabsorption.

• Electrolytes:

  • Sodium (Na+): Major extracellular cation; regulated by hormones.

  • Potassium (K+): Major intracellular cation; regulated by Aldosterone.

  • Calcium (Ca2+): Regulated by PTH, Calcitonin, Calcitriol.

• pH Buffers: Bicarbonate system, Phosphate system, Protein system.

• pH Disorders: Acidosis, Alkalosis.

Metabolism and Nutrition

• Appetite Regulation: Hypothalamic regions stimulate/suppress hunger.

• Appetite Hormones: Cholecystokinin, PYY, Ghrelin, Leptin.

• Metabolic Rate: Energy release rate (kcal/hr, kcal/day).

• Kilocalorie: Heat to raise $1$ kg of water by $1^{ ext{°C}}$.

• Energy Generation: 38 ATP per glucose via cellular respiration.

• Metabolic States: Absorptive State (post-meal; Insulin) vs. Postabsorptive State (uses stored fuel).

• Thermoregulation: Core temperature $37.2^{ ext{°C}}$–$37.6^{ ext{°C}}$; shell temperature $36.6^{ ext{°C}}$–$37.0^{ ext{°C}}$.

The Endocrine System

• Communication Methods: Gap Junctions, Neurotransmitters, Paracrine signals, Hormones.

• Hypothalamus Nuclei: Regulate thirst, temperature, appetite, biological clock, etc.

• Pituitary Gland: Secretes various hormones affecting multiple body systems.

• Thyroid Gland: Regulates metabolism; secretes T3/T4, Calcitonin.

• Adrenal Glands: Medulla (Epinephrine, Norepinephrine) and Cortex (Cortisol, Aldosterone).

• Pancreas: Regulates blood sugar via Glucagon and Insulin.

• Endocrine Disorders: Diabetes Insipidus, Cushing's Disease, Graves' Disease, Diabetes Mellitus.

  The endocrine system is responsible for the secretion of hormones that regulate various bodily functions.

  Important hormones discussed include:

  - ADH (Antidiuretic Hormone) - regulates fluid balance.

  - ANF (Atrial Natriuretic Factor) - regulates sodium balance.

  - Calcitonin and PTH (Parathyroid Hormone) - regulate calcium balance.

  Major Endocrine Glands and Organs

  Glands and Organs Involved:

  - Hypothalamus (brain)

  - Thyroid

  - Thymus

  - Pancreas (both digestive and endocrine functions)

  - Adrenal glands (located above kidneys)

  - Gonads (ovaries and testes)

  Other Organs with Endocrine Function:

  - Heart: produces ANF.

  - Stomach: produces ghrelin.

  Definition: If an organ produces a hormone, it is considered part of the endocrine system.

  Communication in the Endocrine System

  Role of Hormones:

  - Hormones serve as chemical messengers that facilitate communication between cells.

  - Keywords to differentiate between signaling systems:

  - Hormones: Travel through the bloodstream and affect distant cells (endocrine).

  - Paracrine Signals: Act locally within tissues but are not absorbed into the bloodstream.

  - Neurotransmitters: Used for direct communication between neurons and other cells.

  Types of Cellular Communication

  Gap Junctions:

  - Direct connections between neighboring cells that allow sharing of materials, common in cardiac muscle fibers.

  Chemical Signaling via Hormones:

  - Requires the hormone to be taken up into the bloodstream.

  Comparison of Endocrine and Nervous System:

  - Endocrine system uses hormones and is slower with a wider reach; the nervous system uses electrical signals and neurotransmitters and is faster but targets specific cells.

  Differences between the Endocrine and Nervous System

  Speed of Response:

  - Nervous system: actions can occur within milliseconds.

  - Endocrine system: responses can take hours, days, or longer.

  Adaptation:

  - Nervous system: adapts and becomes less responsive over time (e.g., muscle fatigue).

  - Endocrine system: responses persist as long as hormones are present until they are broken down or removed.

  Similarities of the Endocrine and Nervous System

  Overlap in chemical messengers:

  - Some substances act as neurotransmitters in one context and hormones in another, e.g., norepinephrine (noradrenaline) can act as both. (flight or flight response hormone)

  Neuroendocrine Cells:

  - Can function as both neurons and endocrine cells.

  Regulation of Each Other:

  - Systems attempt to balance and coordinate activities; e.g., the hypothalamus integrates signals related to hunger, thirst, and hormones.

  The Hypothalamus

  Function: Master control of the endocrine system, coordinating primitive behaviors (hunger, thirst).

  Structure: Funnel-shaped gland with well-mapped regions (nuclei) for specific behaviors and hormone production.

  Hypothalamic Hormones:

  - Control the anterior and posterior lobes of the pituitary gland.

  - Includes releasing and inhibiting hormones that regulate pituitary activity, e.g., somatostatin inhibits growth hormone secretion.

  The Pituitary Gland

  Location: Suspended from the hypothalamus, sitting in the sella turcica of the sphenoid bone.

  Lobes:

  - Anterior pituitary (adenohypophysis): produces its own hormones.

  - Posterior pituitary (neurohypophysis): stores and releases hormones produced by hypothalamic neurons.

  Pituitary Hormones:

  - Gonadotropins (FSH and LH) - act on gonads for gamete development and sex hormone production.

  - Somatotropins (growth hormone) - affects muscle and bone growth.

  - TSH (Thyroid Stimulating Hormone) - acts on the thyroid gland.

  - ACTH (Adrenocorticotropic hormone) - acts on adrenal glands.

  - Prolactin - stimulates mammary gland development.

  Posterior Pituitary and Hormones

  Hormones Stored and Released:

  - Oxytocin - involved in labor contractions and emotional bonding.

  - ADH - regulates water retention, targets the kidneys.

  Pineal Gland

  Location: Posterior to the hypothalamus.

  Functions:

  - Produces serotonin during the day and converts it to melatonin at night, regulating the sleep-wake cycle.

  - Melatonin helps with sleep and mood regulation.

  - High levels of melatonin associated with seasonal affective disorder (SAD).

  Thymus Gland

  Location: Above the heart, largest in early life.

  Function: Produces thymopoietin and thymosins, which attract T-cells from the bone marrow for immune defense.

  Thyroid Gland

  Location: Below the voice box in the neck.

  Hormones Produced:

  - T3 (Triiodothyronine) and T4 (Thyroxine): regulate metabolism, increase aerobic respiration, and generate heat.

  - Calcitonin: lowers blood calcium levels, promotes bone formation.

  Parathyroid Glands: Produce PTH which raises blood calcium levels, opposite to calcitonin.

  The Pancreas

  Location: Inferior to the stomach, primarily exocrine (98%), only 2% endocrine.

  Endocrine Functions: Produces insulin (lowers blood sugar) and glucagon (raises blood sugar).

  Cells in Pancreatic Islets:

  - Alpha cells: produce glucagon.

  - Beta cells: produce insulin.

  - Delta cells: produce somatostatin (acts against growth hormone).

  Diabetes Mellitus:

  - Type 1: immune system attacks beta cells, decreasing insulin production.

Reproductive Systems and Prenatal Development

• Male Reproductive System: Testes, Epididymis, Vas Deferens, seminal vesicles, prostate.

• Female Reproductive System: Ovaries, Uterine tubes, Uterus, Vagina.

• Reproductive Cycle: Ovarian Cycle (Follicular phase, Ovulation, Luteal phase) and Menstrual Cycle.

• Fertilization and Gestation: Gestation period is $40$ weeks; fertilization window; early development stages.

• Pathologies: Various cancers and developmental disorders.

  Last lecture focused on chromosomes and their role in gender determination.

  Gender Determination:

  - Presence of a Y chromosome leads to development of male (Y chromosome = male).

  - Absence of Y chromosome leads to development of female (default pathway = female).

  - Everyone must have at least one X chromosome, which carries genes beyond sex development.

  Overview of Reproductive Systems

  Characteristics of Reproductive Systems

  Organs:

  - Primary organs produce gametes (sperm and eggs).

  - Secondary organs support natural reproduction processes.

  Characteristics:

  - Developmental features produced during puberty (e.g., muscle and fat changes).

  Male Reproductive System (Chapter 27)

  Male Primary Sex Organs

  Testes:

  - Produce spermatozoa (sperm cells).

  - Structure: Seminiferous tubules.

  - Responsible for both sperm production and hormone production (notably testosterone).

  Sperm Development

  Sperm develops from stem cells within seminiferous tubules.

  Nurse Cells:

  - Assist germ cells in producing sperm.

  - Respond to follicle-stimulating hormone (FSH), which is critical for sperm production.

  Hormonal Regulation

  Gonadotropins:

  - Follicle-Stimulating Hormone (FSH): Involved in both sperm and egg production.

  - Luteinizing Hormone (LH): Stimulates interstitial cells (formerly Leydig cells) to produce testosterone.

  Anatomy of the Male Reproductive System

  Temperature Regulation

  Cremaster Muscle:

  - Suspends testes; regulates temperature by retracting to body or lowering them away for cooling.

  Testes are kept outside the body for optimal sperm production (requires lower temperature).

  Sperm Storage

  Epididymis:

  - Storage site for sperm (40-60 days).

  - After this period, unshed sperm are broken down and recycled.

  Ductus Deferens:

  - Allows sperm to exit epididymis; connects to ejaculatory duct.

  Vasectomy:

  - Procedure that involves cutting the vas deferens to block sperm exit.

  Seminal Fluid Composition

  Components of Seminal Fluid

  Sperm Cells

  - Produced by meiosis; haploid cells.

  - Meiosis results in genetic diversity through synapses (random alignment of chromosomes).

  Fructose:

  - Sugar produced by seminal vesicles, fuels sperm respiration.

  Clotting and Anticoagulants:

  - Help semen adhere to vaginal walls and later free sperm.

  Prostaglandins:

  - Stimulate muscle contractions in female system, aiding sperm transport.

  Spermine:

  - A base to neutralize vaginal acidity, protecting sperm.

  Vulvourethral Glands:

  - Produce lubricants (pre-ejaculatory fluid).

  Sperm Functionality

  Sperm cells have a head (nucleus), body (mitochondria), and tail (flagella for motility).

  Fertilization requires sperm introduction of chromosomes to the egg; nutrient provision by egg for zygote development.

  Sperm Count Trends:

  - Average sperm count has decreased from ≈100,000,000 (1940s) to ≈66,000,000 (1990s); concerns regarding fertility thresholds.

  Female Reproductive System

  Primary Sex Organ

  Ovaries:

  - Responsible for producing gametes (oocytes) through oogenesis.

  - Contain follicles that house developing egg cells.

  Follicle Development

  At Birth:

  - Approximately 2,000,000 primary follicles.

  Puberty:

  - About 400,000 follicles remain; only ~400 will ovulate by menopause.

  Hormonal Regulation of Female Reproductive System

  Follicle-Stimulating Hormone (FSH):

  - Stimulates follicle growth.

  Luteinizing Hormone (LH):

  - Triggers ovulation and acts on corpus luteum.

  Corpus Luteum:

  - Remnant follicle produces hormones (progesterone and estrogen).

  Atresia:

  - Most follicles undergo degeneration; only some complete development to ovulation.

  Egg Development

  Meiosis produces one viable egg and polar bodies (to eliminate extra DNA).

  Antral Fluid:

  - Released with egg; attracts uterine tube for potential fertilization.

  Journey of the Egg and Sperm

  Eggs can become lost without being collected by the uterine tube.

  Ectopic pregnancies can occur if fertilized outside the uterus.

  Sperm can also reach the wrong location, complicating fertilization.

  Sperm viable for approximately 2-10 days.

  Uterine Structure and Function

  Uterine Layers

  Endometrium:

  - Inner layer which thickens and sloughs off during menstrual cycles.

  Myometrium:

  - Muscular layer responsible for uterine contractions during childbirth.

  Menstrual Cycle Dynamics

  Uterine cycle correlated with hormonal changes from FSH and LH, linked to ovulation cycle.

  Endometrial layer buildup is driven by estrogen; its degradation leads to menstruation if no implantation occurs.