Anatomy & Physiology Lab Practical Study Guide

Microscopy

Introduction to the Microscope

The microscope is an essential tool in anatomy and physiology for observing cells, tissues, and microorganisms. Understanding its parts and functions is crucial for accurate laboratory work.

• Ocular lens (eyepiece): The lens you look through, typically with 10x magnification.

• Revolving nosepiece (nosepiece): Holds and rotates the objective lenses.

• Objective lens (objective): Lenses of varying magnification (e.g., 4x, 10x, 40x, 100x) that further magnify the specimen.

• Mechanical stage (stage): Platform where the slide is placed; can be moved to position the specimen.

• Diaphragm adjustment lever: Controls the amount of light passing through the specimen.

• Base: The bottom support structure of the microscope.

• Light switch: Turns the microscope's light source on or off.

• Mechanical stage adjustment knobs: Move the stage left/right and forward/backward.

• Variable light control: Adjusts the intensity of the light source.

• Stage aperture: Opening in the stage that allows light to pass through the specimen.

• Condenser: Focuses light onto the specimen.

• Condenser height adjustment knob: Raises or lowers the condenser to adjust light focus.

• Light source: Provides illumination for viewing specimens.

• Coarse focus knob: Moves the stage up and down for general focusing.

• Fine focus knob: Allows for precise focusing.

• Arm: Supports the body tube and connects it to the base.

• Field of view: The visible area seen through the microscope (not a physical part).

• Total magnification: Calculated by multiplying the ocular lens magnification by the objective lens magnification.

Formula for Total Magnification:

$\text{Total Magnification} = \text{Ocular Magnification} \times \text{Objective Magnification}$

Example: If the ocular lens is 10x and the objective lens is 40x, total magnification is $10 \times 40 = 400x$.

Cell Structure

Basic Cell Components

Cells are the fundamental units of life. Understanding their structure is foundational in anatomy and physiology.

• Nucleus: Contains genetic material (DNA) and controls cellular activities.

• Nucleolus: Site of ribosome synthesis within the nucleus.

• Cytoplasm: Gel-like substance where cellular organelles are suspended.

• Plasma membrane: Semi-permeable membrane that surrounds the cell, controlling entry and exit of substances.

Epithelia

Types of Epithelial Tissue

Epithelial tissues line body surfaces and cavities, providing protection, absorption, and secretion. They are classified by cell shape and number of layers.

• Simple squamous epithelium: Single layer of flat cells; found in areas of diffusion (e.g., alveoli, capillaries).

  • Lumen: The inside space of a tubular structure.

  • Apical surface: The surface facing the lumen or outside.

  • Basal surface: The surface attached to the basement membrane.

• Simple cuboidal epithelium: Single layer of cube-shaped cells; found in glands and kidney tubules.

  • Lumen, apical surface, basal surface

• Simple columnar epithelium: Single layer of tall, column-like cells; lines digestive tract.

  • Lumen, apical surface, basal surface

  • Brush border: Composed of microvilli for absorption.

  • Goblet cell: Secretes mucus.

• Pseudostratified ciliated columnar epithelium: Appears layered but all cells touch the basement membrane; found in respiratory tract.

  • Lumen, apical surface, basal surface, basement membrane, goblet cell

• Stratified squamous epithelium: Multiple layers of flat cells; protects against abrasion (e.g., skin, mouth).

  • Lumen, apical surface, basal surface, basement membrane, basal layer of cells, apical layer (superficial layer) of cells

• Transitional epithelium: Multiple layers; can stretch (e.g., urinary bladder).

  • Lumen, apical surface, basal surface, basement membrane, basal layer of cells, apical layer (superficial layer) of cells

Connective Tissues

Types and Functions

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

• Areolar connective tissue: Loose arrangement of fibers; provides support and flexibility.

  • Fibroblast, extracellular matrix, ground substance, collagen fiber, elastic fiber

• Adipose tissue: Stores fat for energy and insulation.

  • Adipocyte, fat vacuole

• Dense regular connective tissue: Parallel collagen fibers; found in tendons and ligaments.

  • Fibroblast, extracellular matrix, ground substance, collagen fiber

• Dense irregular connective tissue: Irregularly arranged collagen fibers; provides strength in multiple directions (e.g., dermis).

  • Fibroblast, collagen fiber, ground substance

• Hyaline cartilage: Smooth, glassy cartilage; found in joints, nose, trachea.

  • Chondrocyte, lacuna, extracellular matrix, perichondrium

• Elastic cartilage: Flexible cartilage; found in ear, epiglottis.

  • Chondrocyte, lacuna, extracellular matrix, ground substance, elastic fiber, perichondrium

• Fibrocartilage: Tough, shock-absorbing cartilage; found in intervertebral discs.

  • Chondrocyte, lacuna, extracellular matrix, ground substance, collagen fiber

• Bone: Rigid connective tissue; supports and protects organs.

  • Osteocyte, lacuna, canaliculus, extracellular matrix, osteon, central canal

• Blood: Fluid connective tissue; transports gases, nutrients, and wastes.

  • Erythrocyte (red blood cell), leukocyte (white blood cell), thrombocyte (platelet)

Additional info: For blood, identification of specific leukocyte types is not required for the first lab exam.

Nervous Tissue

Structure and Function

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

• Neuron: The primary cell type; transmits nerve impulses.

  • Cell body, nucleus, nucleolus

• Glia (neuroglial cells): Support, protect, and nourish neurons.

Muscle Tissues

Types of Muscle Tissue

Muscle tissues are responsible for movement and force generation. There are three main types:

• Skeletal muscle: Voluntary, striated muscle attached to bones.

  • Sarcolemma (plasma membrane), sarcoplasm (cytoplasm), striations

• Cardiac muscle: Involuntary, striated muscle found in the heart.

  • Sarcolemma, sarcoplasm, striations, intercalated discs

• Smooth muscle: Involuntary, non-striated muscle found in walls of hollow organs.

  • Sarcolemma, sarcoplasm

Skin and Hypodermis

Layers of the Skin

The skin is composed of multiple layers, each with distinct functions and structures.

• Epidermis: Outermost layer; provides protection.

  • Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

• Dermis: Middle layer; provides strength and elasticity.

  • Papillary layer (areolar connective tissue), dermal papilla, reticular layer (dense irregular connective tissue)

• Hypodermis: Subcutaneous layer; stores fat and anchors skin.

Organ Systems Overview

Major Organs and Structures

Understanding the major organs and their locations is essential for gross anatomy.

• Respiratory System: trachea, lung, parietal pleura, visceral pleura, diaphragm

• Cardiovascular System: heart, aorta, vena cava, visceral pericardium

• Urinary System: kidney, ureter, urinary bladder

• Digestive System: esophagus, stomach, small intestine, large intestine, liver, visceral peritoneum

• Lymphatic System: lymph nodes, spleen

• Nervous System: brain, spinal cord

Additional info: For practical exams, be able to identify these organs and structures on models or images.