Anatomy & Physiology Lab Study Guide: Microscopy, Histology, and Organ Systems

Study Guide - Smart Notes

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Microscopy

Compound Light Microscope Structure and Function

The compound light microscope is a fundamental tool in anatomy and physiology labs, used to observe cells and tissues at high magnification. Understanding its components and how to calculate total magnification is essential.

Ocular lens: The lens you look through, typically 10x magnification.
Revolving nosepiece: Holds objective lenses and allows switching between them.
Objective lenses: Usually 4x, 10x, 40x, and 100x magnification.
Mechanical stage: Platform where the slide is placed.
Diaphragm adjustment lever: Controls the amount of light passing through the specimen.
Base: Supports the microscope.
Light switch: Turns the illumination on or off.
Stage adjustment controls: Move the slide horizontally and vertically.
Variable light control: Adjusts light intensity.
Stage aperture: Opening in the stage for light to pass through.
Condenser: Focuses light onto the specimen.
Condenser height adjustment knob: Raises or lowers the condenser.
Filter holder: Holds filters for contrast enhancement.
Coarse focus knob: For large adjustments in focus.
Fine focus knob: For precise focusing.
Arm: Used to carry the microscope.

Field of view: The visible area when looking through the microscope. Not a physical part, but important for microscopy.

Total Magnification Formula:

Example: If the ocular lens is 10x and the objective lens is 40x, total magnification is .

Histology

General Cell Structures

Cells have common structures that can be identified in most tissue samples.

Nucleus: Contains genetic material; visible in most cells.
Cytoplasm: The area outside the nucleus, containing organelles (not always labeled in PAL Histology).

Epithelial Tissue

Epithelial tissues line surfaces and cavities of organs. They are classified by cell shape and number of layers.

Apical surface: The free surface of epithelial cells (not always labeled).
Basal surface: The surface attached to the basement membrane.
Basement membrane: Thin layer anchoring epithelium to underlying tissue.

Types of Epithelia

Simple squamous epithelium: Single layer of flat cells; found in lung alveoli, blood vessels.
Simple cuboidal epithelium: Single layer of cube-shaped cells; found in kidney tubules.
Simple columnar epithelium: Single layer of tall, column-like cells; found in digestive tract.
Pseudostratified columnar epithelium: Appears layered but all cells touch the basement membrane; found in trachea.
Stratified squamous epithelium: Multiple layers; protects against abrasion; found in skin, mouth.
Transitional epithelium: Multiple layers; cells change shape; found in urinary bladder.

Connective Tissues

Connective tissues support, bind, and protect organs. They vary in cell type, matrix composition, and function.

Areolar connective tissue: Loose arrangement of fibers; found under epithelia.
Adipose tissue: Stores fat; insulates and cushions organs.
Dense regular connective tissue: Parallel collagen fibers; found in tendons and ligaments.
Dense irregular connective tissue: Irregularly arranged fibers; found in dermis of skin.

Cartilage Types

Hyaline cartilage: Most common; found in nose, trachea, ends of long bones.
Elastic cartilage: Flexible; found in ear, epiglottis.
Fibrocartilage: Tough; found in intervertebral discs, pubic symphysis.

Bone Tissue

Osteocyte: Mature bone cell, found in lacunae.
Lacuna: Small cavity housing osteocyte.
Canaliculi: Tiny channels connecting osteocytes.
Central canal: Contains blood vessels and nerves.

Blood Tissue

Erythrocytes: Red blood cells; carry oxygen.
Leukocytes: White blood cells; immune function.
Platelets: Cell fragments; involved in clotting.

Nervous Tissue

Nervous tissue is specialized for communication via electrical and chemical signals.

Neuron: Main cell type; transmits impulses.
Neuron process: Includes axons and dendrites.
Neuroglia: Supporting cells; maintain neuron health.

Muscle Tissues

Muscle tissues are responsible for movement and force generation.

Skeletal muscle: Voluntary; striated; attached to bones.
Cardiac muscle: Involuntary; striated; found in heart; contains intercalated discs.
Smooth muscle: Involuntary; non-striated; found in walls of hollow organs.

Skin and Hypodermis

The skin is composed of multiple layers, providing protection and sensation.

Epidermis: Outer layer; contains stratified squamous epithelium.
Dermis: Middle layer; contains connective tissue, blood vessels, nerves.
Hypodermis: Deepest layer; contains adipose tissue.

Organ Systems and Key Structures

Identification of major organs and structures is essential for understanding human anatomy.

Respiratory System

Trachea: Windpipe; conducts air to lungs.
Lung: Main organ of respiration.
Parietal pleura: Outer membrane lining thoracic cavity.
Visceral pleura: Inner membrane covering lungs.
Diaphragm: Muscle for breathing.

Cardiovascular System

Heart: Pumps blood throughout the body.
Aorta: Main artery leaving the heart.

Urinary System

Kidney: Filters blood, produces urine.
Ureter: Transports urine from kidney to bladder.
Urinary bladder: Stores urine.

Digestive System

Esophagus: Transports food to stomach.
Stomach: Digests food.
Small intestine: Absorbs nutrients.
Colon: Absorbs water, forms feces.
Liver: Processes nutrients, detoxifies.

Lymphatic System

Axillary nodes: Lymph nodes in armpit.
Inguinal nodes: Lymph nodes in groin.
Spleen: Filters blood, immune function.

Nervous System

Brain: Central organ of nervous system.
Spinal cord: Transmits signals between brain and body.

Summary Table: Epithelial Tissue Types

Type	Cell Shape	Layers	Location
Simple squamous	Flat	1	Alveoli, blood vessels
Simple cuboidal	Cube-shaped	1	Kidney tubules
Simple columnar	Tall, column-like	1	Digestive tract
Pseudostratified columnar	Varied	1 (appears layered)	Trachea
Stratified squamous	Flat	Multiple	Skin, mouth
Transitional	Varied	Multiple	Urinary bladder

Summary Table: Connective Tissue Types

Type	Main Cells	Matrix/Fibers	Location
Areolar	Fibroblasts	Collagen, elastic, reticular	Under epithelia
Adipose	Adipocytes	Few fibers	Hypodermis, around organs
Dense regular	Fibroblasts	Parallel collagen	Tendons, ligaments
Dense irregular	Fibroblasts	Irregular collagen	Dermis
Hyaline cartilage	Chondrocytes	Matrix, collagen	Nose, trachea, ends of bones
Elastic cartilage	Chondrocytes	Elastic fibers	Ear, epiglottis
Fibrocartilage	Chondrocytes	Collagen fibers	Intervertebral discs
Bone	Osteocytes	Collagen, mineralized matrix	Skeletal system
Blood	Erythrocytes, leukocytes, platelets	Plasma	Blood vessels

Additional info: Some details, such as the function of certain cell types and tissue locations, have been inferred for completeness and clarity.