BIOL 1161 Anatomy Lab Notes: Introduction to Anatomy, Microscopes, and Embryology

Welcome to BIOL 1161 Anatomy Lab

Instructor Information

• Instructor: Dr. Dalfrey

Daily Agenda

Today's session in BIOL 1161 Anatomy Lab will cover:

• Review of the course syllabus, instructor policies, and related administrative details.
• Discussion of the hierarchy of organization in Anatomy.
• Introduction to the parts and usage of the Compound Light Microscope.
• Introduction to embryological germ layers.

Organization in Anatomy & Physiology

Basic Units

• The simplest body structure considered alive is a Cell.
• A group of cells with a similar function is a Tissue.

Hierarchy of Organization (Most Complex to Simplest / Simplest to Most Complex)

• Organism: A complete living being.
• Organ System: A group of organs working together to perform major functions (e.g., Circulatory System, Nervous System).
• Organ: A structure made of two or more tissues working together to perform a specific function (e.g., Brain, Heart, Liver).
• Tissue: A group of similar cells working together to perform a specific function.
• Cell: The basic structural and functional unit of all known organisms.

Anatomy of a Cell (Key Organelles)

The following are major components seen within a typical cell:

• Plasma Membrane: The outer boundary of the cell.
• Nucleus: Contains the cell's genetic material.
  • Nuclear Envelope: The double membrane surrounding the nucleus.
  • Nucleolus: Involved in ribosome synthesis.
  • Chromatin: DNA and proteins that form chromosomes.
  • Nuclear Pore: Regulates the passage of molecules into and out of the nucleus.
• Cytoplasm: The material or protoplasm within a living cell, excluding the nucleus.
• Mitochondrion: Powerhouse of the cell, responsible for ATP synthesis.
• Rough Endoplasmic Reticulum (RER): Involved in protein synthesis and modification, often studded with ribosomes.
• Ribosomes: Sites of protein synthesis, found free in the cytoplasm or attached to the RER.
• Peroxisome: Involved in metabolic processes, including fatty acid breakdown.
• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
• Secretory Vesicle: Transports substances from the Golgi apparatus to the cell exterior for secretion.
• Lysosome: Contains digestive enzymes to break down waste materials and cellular debris.
• Centrioles: Involved in cell division in animal cells.
• Microtubule: Component of the cytoskeleton, involved in cell shape and transport.
• Smooth Endoplasmic Reticulum (SER): Involved in lipid synthesis, detoxification, and calcium storage.

Cells Mentioned

• Brain cells
• Liver cells
• Muscle cells
• Blood cells
• Intestinal cells

Tissue Types

• Nerve tissue
• Connective tissue
  • Blood
  • Adipose
  • Cartilage
  • Loose connective
  • Bone
  • Dense
• Epithelial tissue
  • Pseudostratified ciliated columnar
  • Simple squamous
  • Simple cuboidal
  • Simple columnar
  • Stratified squamous
• Muscle tissue
  • Cardiac
  • Smooth
  • Skeletal

Microbial Notes: Types of Microscopes

Different Microscope Types

• Light Microscope
• Fluorescence Microscope
• Electron Microscope
• Stereo Microscope
• Confocal Microscope
• Atomic Force Microscope
• Inverted Microscope
• Retinal Imaging Microscope

Scale of Observation

Objects observable by different instruments, from macroscopic to atomic:

• Human Eye:
  • Child: 1 ext{ m} to 10^1 ext{ m}
  • Hand: 10 ext{ cm}
  • Fingerprint: 1 ext{ mm}
  • Strand of hair: 100 ext{ extmu m}
• Light Microscope:
  • Bacteria: 1 ext{ extmu m}
  • Nerve / Micro Processor: 10 ext{ extmu m}
• Electron Microscope:
  • Virus: 100 ext{ nm}
  • DNA / Transistor Gate Length: 10 ext{ nm}
  • Atom: 1 ext{ ext{
    ormalfont Å}} (Angstrom) or 0.1 ext{ nm}

Compound Light Microscope Parts and Functions

Calculating Magnification

Total Magnification is calculated by multiplying the objective lens magnification by the ocular lens magnification.

• Scanning Power: (Scanning Objective Lens Magnification) imes (Ocular Lens Magnification)
• Low Power: (Low Power Objective Lens Magnification) imes (Ocular Lens Magnification)
• High Power: (High Power Objective Lens Magnification) imes (Ocular Lens Magnification)

Parfocal Feature

• Definition: A parfocal microscope allows the image to remain in focus (or nearly in focus) when switching between objective lenses after initially focusing at one magnification (e.g., scanning power).
• Practice Observations:
  • Image Orientation: When looking through the eyepiece, the image appears inverted and reversed compared to its actual orientation on the slide.
  • Image Movement: If the slide is moved to the right, the image observed through the ocular appears to move to the left. If the slide is moved to the left, the image appears to move to the right.

Embryonic Development

Overview of Development

• Development: A series of orderly, precise steps that transform a zygote into a multicellular embryo during the early stage of development of a multicellular organism.
• Includes:
  1. Cell Division: Rapid increase in cell number.
  2. Cell Growth: Increase in cell size.
  3. Cell Differentiation: The process by which unspecialized embryonic cells change into specialized cells, tissues, and organs.

Early Embryonic Development: Cleavage

• Phase Description: Cleavage is the first major phase of embryonic development.
• Process: It involves a rapid succession of mitotic cell divisions.
• Outcome: Creates a multicellular embryo from the zygote.
• Key Characteristic: There is NO growth during cleavage; the overall size of the embryo does not increase, only the number of cells.
• Stages:
  1. Zygote: A single fertilized egg cell.
  2. 2-cell stage, 4-cell stage, 8-cell stage: Successive divisions of the zygote.
  3. Morula: A solid ball of cells (many cells).
  4. Blastula: A single layer of cells surrounding a fluid-filled cavity called the blastocoel (a hollow ball).

Embryonic Development: Gastrulation

• Phase Description: Gastrulation is the second major phase of embryonic development, occurring after cleavage.
• Process: Cells at one end of the blastula move inward.
• Outcome: Adds more cells to the embryo and sorts all cells into three distinct cell layers.
• Transformation: The embryo is transformed from the blastula into the gastrula.

Formation of Tissues and Organs

• Mechanisms: Changes in cell shape, cell migration, and programmed cell death (apoptosis) give form to the developing animal.
• Tissues and organs take shape as a result of:
  • Cell shape changes
  • Cell migration

Embryonic Germ Layers

After gastrulation, the embryo consists of three primary germ layers, which differentiate into specific tissues and organ systems:

• Ectoderm Cells: Eventually develop into the skin (epidermis) and nervous tissue (brain, spinal cord, nerves) of the animal.
• Endoderm Cells: Develop into the lining of the animal’s digestive tract and into organs associated with digestion (e.g., liver, pancreas).
• Mesoderm Cells: Develop into the muscles, circulatory system, excretory system, and, in some animals, the respiratory system (e.g., lungs).

Organ Formation

• Organs begin to form after gastrulation is complete.
• The embryonic tissue layers (germ layers) start to differentiate into specific tissues and organ systems.

Reminders for Today and Course Success

• Stay on Pace: Keep up with the course material and assignments.
• Submit on Time: Ensure all assignments are submitted by their deadlines.
• Attend Each Class Session: Regular attendance is crucial for understanding the material.
• Take Advantage of Office Hours: Utilize office hours for questions and additional help.
• Participate in Class and Ask Questions: Active engagement enhances learning and comprehension.