Introduction to Microscopes, Cells, Tissues & Blood – Key Vocabulary

Vocabulary flashcards covering microscope components, cell structure, tissue types, and blood composition for exam review.

Eyepiece (Ocular) Lens

Top lens of a microscope, usually 10× magnification; can be monocular or binocular.

Tube (Body Tube)

Connects the eyepiece lens to the objective lenses on a microscope.

Arm (Microscope)

Curved structure that supports the tube and connects it to the base; used to carry the microscope.

Base (Microscope)

Bottom support structure of a microscope, providing stability.

Illuminator

Built-in light source located in the base of a microscope.

Stage

Flat platform where microscope slides are placed; usually fitted with stage clips.

Stage Clips

Metal clips that hold a microscope slide securely on the stage.

Revolving Nosepiece (Turret)

Rotating disk that houses objective lenses and allows switching between magnifications.

Objective Lens

Microscope lenses providing 4×, 10×, 40×, or 100× magnification; 100× used with immersion oil.

Rack Stop

Mechanical stop preventing the high-power objective from crashing into and breaking the slide.

Iris Diaphragm

Rotating disk beneath the stage that adjusts light intensity and image contrast.

Coarse Adjustment Knob

Large focus knob used ONLY with low-power objectives to bring the image into rough focus.

Total Magnification

Product of objective lens magnification × eyepiece magnification (e.g., 40× objective ×10 = 400×).

Scientific Drawing Rules

Use sharp pencil, no shading, provide title, draw in ruled box, label parts, state magnification, add scale.

Cell

Smallest unit capable of performing all life functions; all organisms are composed of cells.

Cell Membrane

Phospholipid bilayer with proteins; regulates entry and exit of substances in the cell.

Cytoplasm

Jelly-like material inside the cell membrane that contains cytosol and organelles.

Cytosol

Liquid component of cytoplasm (75–90 % water); site of many metabolic reactions.

Nucleus

Largest organelle containing DNA; enclosed by double nuclear envelope with pores.

Ribosome

Small spherical structure (free or on ER) where proteins are synthesized.

Endoplasmic Reticulum (ER)

Membranous network continuous with nucleus; rough ER makes proteins, smooth ER makes lipids & detoxifies.

Golgi Body (Apparatus)

Stack of flattened membranes that modify, package, and form vesicles for protein secretion.

Lysosome

Membrane-bound vesicle containing digestive enzymes that break down waste and old organelles.

Mitochondrion

Double-membraned organelle with folded inner membrane; site of cellular respiration and ATP production.

Cytoskeleton

Network of protein fibres providing cell shape, internal support, and intracellular transport.

Cilia

Short, numerous surface projections that move substances over the cell.

Flagellum

Long, single projection that propels the cell (e.g., human sperm).

Inclusions

Non-living chemicals in cytoplasm (e.g., hemoglobin, melanin) not considered organelles.

Tissue

Group of similar cells working together for a specific function.

Epithelial Tissue

Closely joined cells forming coverings and linings of organs and body surfaces.

Connective Tissue

Tissue type that supports, connects, or separates different body parts; cells embedded in matrix.

Cartilage

Connective tissue that cushions joints.

Tendons

Dense connective tissue that connects muscle to bone.

Ligaments

Dense connective tissue that connects bone to bone.

Adipose Tissue

Connective tissue specialized for fat storage and insulation.

Bone (Osseous Tissue)

Rigid connective tissue providing support and protection; stores minerals.

Muscle Tissue

Contractile tissue; types include skeletal, smooth, and cardiac.

Skeletal Muscle

Voluntary muscle attached to bones, producing body movement.

Smooth Muscle

Involuntary muscle found in walls of organs and blood vessels.

Cardiac Muscle

Involuntary, striated muscle forming the heart wall; contracts to pump blood.

Nervous Tissue

Tissue composed mainly of neurons; found in brain, spinal cord, and nerves.

Cardiovascular System

Organ system that transports blood, nutrients, gases, and wastes via heart and vessels.

Plasma

Liquid portion of blood (~55 %), mostly water with dissolved nutrients, wastes, hormones, proteins, antibodies.

Formed Elements

Cellular components of blood (~45 %): erythrocytes, leukocytes, and thrombocytes.

Erythrocyte (Red Blood Cell)

Biconcave, anucleate cell containing hemoglobin; transports oxygen; lifespan ≈120 days.

Hemoglobin

Iron-containing protein in RBCs that binds oxygen to form oxyhemoglobin.

Oxyhemoglobin

Hemoglobin bound to oxygen; carries ~97 % of transported O₂.

Leukocyte (White Blood Cell)

Immunological cells (~1 % of blood) that defend against infection; include neutrophils, etc.

Neutrophil

Most common leukocyte containing enzymes that engulf and digest pathogens.

Thrombocyte (Platelet)

Small cytoplasmic fragment from megakaryocytes; vital for blood clotting; lifespan 7-10 days.

Carbaminohemoglobin

Compound formed when CO₂ binds to hemoglobin (~22 % of CO₂ transport).

Bicarbonate Ion (HCO₃⁻)

Major form (≈70 %) in which carbon dioxide is transported in plasma.