Human Anatomy and Physiology 1: Chemistry and Cell Structures

Course Introduction and Instructor Background

• Instructor Profile: The course is led by Doctor Yates, a chiropractor who has been in clinical practice since 2008.

• Teaching Experience: Doctor Yates has been teaching in both online and in-person environments since 2011.

• Clinical Background: Experience includes working in medical offices, chiropractic offices, and collaborating with nurse practitioners, medical doctors, and orthopedic specialists. The experience is primarily in outpatient settings rather than hospitals.

• Course Navigation and Expectations:

  • Feeling overwhelmed during the first two weeks is considered a normal part of the learning process for new and experienced students alike.

  • Students are encouraged to check weekly announcements, which contain comprehensive lists of due dates, curriculum coverage, and specific tasks.

  • Course modules are designed to be intuitive; however, the instructor provided a cell phone number in both the syllabus and announcements for direct contact via call or text.

Course Policies and Academic Integrity

• Late Assignment Policy:

  • There is a grace period for the first couple of weeks while students acclimate.

  • After the initial two weeks, a strict "no late assignments" policy is enforced.

  • This policy follows college standards and is intended to manage instructor workload (e.g., preventing scenarios where an instructor must grade 11 late papers for a single student on a Friday night).

• Generative AI Policy:

  • Copying and pasting AI-generated content directly into assignments is a violation of the honor code.

  • Students must become experts on the topics to identify when AI provides incorrect or superficial information.

  • Common AI errors: The instructor noted that many students using similar prompts produced papers with the exact same incorrect information.

  • AI is viewed as a powerful tool for digging deeper and enhancing work, but not as a replacement for individual effort.

  • Developing a working knowledge of how to use AI properly is identified as a highly sought-after professional skill.

Assignment and Grading Structure

• Weekly Deliverables (Five Main Tasks):

  • Homeostasis Paper: One written assignment per week focusing on a specific body system and how it maintains homeostasis. This must be submitted as a Word document or a PDF. Formats like Google Pages are not supported.

  • Lecture Keywords: Students must provide two keywords for the lecture to verify participation. Summaries are not required.

  • Lab Keywords: Two keywords for the lab section.

  • Lecture Quiz: A content-based assessment on the week's lecture.

  • Lab Quiz: An assessment based on lab content, often featuring graphics and pictures similar to an in-person lab environment.

• Submission Rules:

  • Assignments must be submitted via the Dropbox; emailed assignments are not accepted for record-keeping purposes.

  • Submissions are only possible while the specific module is active.

• Discussions: There are no discussion board assignments in this course; they are replaced by written assignments.

• Grading Timeline: Grades are posted no later than the Friday following the submission deadline. Early submissions are encouraged to allow the instructor more time to provide quality feedback.

Basic Chemistry and Elements of Life

• Matter: Defined as anything that has mass and takes up space.

• Elements: There are $92$ naturally occurring elements on the periodic table.

• Atomic Structure:

  • Nucleus: Contains Protons (positive charge) and Neutrons (neutral/no charge).

  • Electrons: Have a negative charge and orbit the nucleus in shells.

  • Stability: In a stable element, the number of protons and electrons are always equal.

• The $2, 8, 8$ Rule (Electron Shells):

  • The first shell has a maximum capacity of $2$ electrons.

  • The second shell has a maximum capacity of $8$ electrons.

  • The third shell prefers $8$ electrons but can technically hold up to $18$.

  • The fourth shell has a maximum of $32$ electrons.

  • For healthcare board exams, the instructor emphasizes remembering the $2, 8, 8$ sequence for stability.

pH and Chemical Compounds

• pH Scale: A measure of the concentration of Hydrogen ions ($H^+$).

  • Neutral: A pH of $7$ is neutral.

  • Acidic: pH levels below $7$ (e.g., wine, citrus, Coca-Cola).

  • Basic (Alkaline): pH levels between $7$ and $14$ (e.g., bleach, soaps, kale).

  • Blood pH: Normal range is between $7.35$ and $7.45$. Staying outside this range for too long prevents homeostasis and is incompatible with life.

• Classification of Compounds:

  • Organic Compounds: Must contain both carbon and hydrogen (e.g., "carbon-based life forms").

  • Inorganic Compounds: Do not contain both carbon and hydrogen concurrently (e.g., Water ($H_2O$) or Hydrochloric acid ($HCl$)).

Biological Molecules (Macromolecules)

• Carbohydrates: The primary source of fuel/energy for the body, particularly the heart and brain.

  • Monosaccharides: Single sugar molecules; the easiest to break down for immediate energy.

  • Disaccharides: Two sugar molecules linked together.

  • Polysaccharides: Complex structures with multiple sugar pieces; they take longer to digest.

  • Clinical Application: Triathletes use energy gels containing a mix of all three to provide immediate and sustained energy releases.

• Lipids: Stored form of energy.

  • Phospholipids: Form the "phospholipid bilayer" which is the outer covering of every cell in the body.

  • Functions: Used in steroid hormones and as protective coverings for the nervous system (brain, spinal cord, and nerves).

• Proteins: The structural building blocks of the body, including enzymes and membrane receptors.

  • Amino Acids: The building blocks of proteins. Examples include phenylalanine, isoleucine, and leucine.

  • Protein Structure:

    1. Primary Structure: The sequence of amino acids.

    2. Alpha Helix: A curling secondary structure.

    3. Tertiary Structure: The chain bends back on itself, forming polypeptide chains based on positive/negative attractions.

    4. Quaternary Structure: A complex, modular protein formed by multiple attracted chains.

• Nucleic Acids: The genetic blueprints.

  • DNA (Deoxyribonucleic acid): Double-stranded; contains Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). Nitrogenous bases pair as $A-T$ and $C-G$.

  • RNA (Ribonucleic acid): Single-stranded copy used for protein synthesis; replaces Thymine with Uracil (U).

• ATP (Adenosine Triphosphate): The primary energy currency of the cell.

Cell Structure and Organelles

• Plasma Membrane (Phospholipid Bilayer): Separates the exterior of the cell from the interior.

  • Phosphoric Head: Hydrophilic (water-liking); faces the fluid environment inside and outside the cell.

  • Lipid Tail: Hydrophobic (water-fearing); points inward away from water.

  • Fluid Mosaic Model: Includes integral/transmembrane proteins and carbohydrate chains used for signaling and docking.

• Cytoplasm: A gel-like substance (compared to "ectoplasm") filling the space between the organelles.

• The Nucleus: The control center.

  • Nucleolus: The inner part containing the highest concentration of chromatin.

  • Nuclear Pores: Openings that allow RNA (the copy of the blueprint) to move out of the nucleus to the ribosomes.

• Endoplasmic Reticulum (ER):

  • Rough ER: Covered in ribosomes; responsible for protein synthesis.

  • Smooth ER: No ribosomes; responsible for producing phospholipids and other lipids.

• Ribosomes: Sites of amino acid assembly. Can be attached to the Rough ER or exist as "free ribosomes."

• Golgi Apparatus (Golgi Complex): Acts like a "Post Office" or "UPS Store." It packages, labels, and ships molecules to their destination, often located closer to the cell membrane.

• Mitochondria: The powerhouse of the cell; produces ATP through aerobic respiration. They uniquely contain their own DNA separate from the nucleus.

• Lysosomes and Peroxisomes: Act as the "stomach" or "garbage can" of the cell, breaking down old parts or harmful substances to be excreted.

• Cytoskeleton: Provides structural support via microfilaments and microtubules.

• Centrioles: Cylindrical structures involved only in cell replication/division, where they help split DNA.

Cell Extensions and Tissues

• Cell Extensions:

  • Cilia: Whip-like extensions on the surface that move substances (e.g., clearing dust or debris from the lungs).

  • Microvilli: Finger-like projections that increase surface area for better absorption in the digestive tract.

  • Flagella: A singular long extension used for movement; found only in sperm cells in humans.

• Main Tissue Types:

  • Epithelial Tissue: Covers inner and outer surfaces and organs.

    • Squamous: Flat or "squashed" cells.

    • Cuboidal: Cube-shaped cells.

    • Columnar: Rectangular, column-shaped cells.

    • Simple: A single layer of cells.

    • Stratified: Multiple layers of cells.

    • Pseudostratified: Appears layered due to nuclei misalignment but is actually a single layer (often ciliated columnar epithelial).

  • Connective Tissue: Supports and binds structures together.

    • Fibers: Collagen (strength), Elastic (stretch and return), Reticular (supporting mesh).

    • Types: Adipose (fat), Fibrous (tendons/ligaments), Cartilage (Hyaline, Elastic, and Fibrocartilage found in the spine), Bone (Spongy and Compact).

    • Blood: Historically and clinically classified as a connective tissue.

  • Muscle Tissue:

    • Skeletal: Voluntary control; looks like "train tracks" (striated); can be multinucleated.

    • Cardiac: Found only in the heart; involuntary; has branching Y-shapes and intercalated discs.

    • Smooth: Found in arteries, veins, and the digestive system; involuntary; manages diameter changes.

  • Nervous Tissue: Found in the brain, spinal cord, and nerves.

    • Neurons: Conduct electrical signals via axons to neuromuscular junctions.

    • Neuroglia: Support cells for the neurons.

Homeostasis and Feedback Loops

• Homeostasis: The dynamic equilibrium required to maintain life by responding to internal and external changes.

• Clinical Examples:

  • Blood Sugar Regulation: High blood sugar triggers insulin release from the pancreas to move glucose into cells. Low blood sugar triggers glucagon to release stored glucose from the liver.

  • Body Temperature: The body works to stay near $98.6$ degrees Fahrenheit. Deviations can lead to conditions like hypothermia (even in relatively mild $78$-degree water over a long duration).

• Feedback Loops:

  • Negative Feedback Loop: The most common type; it reverses a change to bring the body back to a neutral set point (e.g., temperature and blood sugar regulation).

  • Positive Feedback Loop: Triggers an escalating reaction that moves away from the starting point (e.g., childbirth, where initial contractions trigger hormones leading to stronger and faster contractions).

• Three Components of a Feedback Loop:

  1. Receptor: Measures the specific variable (e.g., blood sugar level).

  2. Control Center: Contains the "set point" and decides if action is needed.

  3. Effector: Executes the response to the change.

Questions & Discussion

• Question: A student asked about the general lecture and lab requirements.

• Answer: Dr. Yates clarified that the course includes weekly written homeostasis papers, keywords for both lecture and lab to track participation, and two quizzes (one for lecture content and one for lab graphics). It was noted that there are no discussion assignments, and all work must be in PDF or Word format submitted to the Dropbox. If students encounter issues, they are encouraged to call or text the instructor's cell phone listed in the syllabus.