BI231 Midterm Study Guide: Anatomy & Physiology Essentials

Orientation to Anatomy & Physiology

Anatomy vs. Physiology

Anatomy and physiology are foundational sciences for understanding the human body. Anatomy focuses on the structure, while physiology examines function.

• Anatomy: Study of body structure, including organs, tissues, and systems.

• Physiology: Study of body function, explaining how anatomical structures work.

Levels of Structural Organization

The human body is organized hierarchically from simple to complex structures.

• Chemical: Atoms and molecules (e.g., water, proteins).

• Cellular: Cells, the basic unit of life.

• Tissue: Groups of similar cells performing a function.

• Organ: Structures composed of multiple tissue types.

• Organ System: Groups of organs working together (e.g., digestive system).

• Organism: The complete living individual.

Homeostasis

Homeostasis is the maintenance of a stable internal environment.

• Negative feedback: Reverses a change to maintain stability (e.g., body temperature regulation).

• Positive feedback: Amplifies a change until an endpoint is reached (e.g., blood clotting).

Language of Anatomy

Standardized terms describe locations and positions in the body.

• Anatomical position: Standing upright, feet forward, arms at sides, palms forward.

• Directional terms: Superior/inferior, anterior/posterior, medial/lateral, proximal/distal, superficial/deep.

Body Planes

• Sagittal: Divides body into left and right.

• Frontal (coronal): Divides body into anterior and posterior.

• Transverse: Divides body into superior and inferior.

Body Cavities

Body cavities house organs and provide protection.

• Dorsal cavity: Includes cranial (brain) and spinal (spinal cord) cavities.

• Ventral cavity: Includes thoracic and abdominopelvic cavities, separated by the diaphragm.

Serous Membranes (Ventral Body Cavity)

• Parietal layer: Lines cavity wall.

• Visceral layer: Covers organ.

• Pericardium: Heart.

• Pleura: Lungs.

• Peritoneum: Intestines.

Tissues

Four Types of Tissue (C-MEN)

The body is composed of four primary tissue types, each with distinct functions.

• Connective

• Muscle

• Epithelial

• Nervous

Connective Tissue

Connective tissue supports, protects, and binds other tissues.

• Characteristics: Matrix, cells, fibers; usually vascular (except cartilage).

• Connective Tissue Proper:

  • Loose CT: Areolar, Adipose, Reticular

  • Dense CT: Dense regular, Dense irregular, Elastic

• Cell Types: Fibroblasts, fibrocytes

• Cartilage: Hyaline, Elastic, Fibrocartilage; cells: chondroblasts, chondrocytes

• Bone: Compact, Spongy; cells: osteogenic cells, osteoblasts, osteocytes, osteoclasts

• Blood: Cells: RBCs, WBCs, platelets

Muscle Tissue

Muscle tissue enables movement through contraction.

• Skeletal: Voluntary, striated

• Cardiac: Involuntary, striated

• Smooth: Involuntary, non-striated

Epithelial Tissue

Epithelial tissue covers surfaces and lines cavities.

• Cell Shapes: Squamous, cuboidal, columnar

• Arrangements:

  • Simple: squamous, cuboidal, columnar, pseudostratified

  • Stratified: squamous, cuboidal, columnar, transitional

Membranes, Glands & Nervous Tissue

Membranes

Membranes are sheets of tissue that cover surfaces or line cavities.

• Mucous: Lines body cavities open to exterior

• Serous: Lines ventral cavities

• Cutaneous: Skin

Glands

Glands secrete substances for various functions.

• Endocrine: Secrete hormones into blood

• Exocrine: Secrete products into ducts

• Modes of secretion: Merocrine, apocrine, holocrine

Nervous Tissue

Nervous tissue is specialized for communication.

• Neurons: Transmit electrical signals

• Neuroglia: Support, protect, insulate neurons

Integumentary System

Epidermis (Deep → Superficial)

The epidermis is the outermost layer of skin, composed of several strata.

• Stratum basale (germinativum)

• Stratum spinosum

• Stratum granulosum

• Stratum lucidum (thick skin only)

• Stratum corneum

• Keratinocytes: Produce keratin for protection

• Melanocytes: Produce melanin for skin color & UV protection

• UV light: Stimulates Vitamin D synthesis, essential for calcium absorption and bone health

Dermis

The dermis provides structural support and houses appendages.

• Papillary layer (20%): Contains dermal papillae

• Reticular layer (80%): Dense irregular connective tissue

Skin Color Factors

• Melanin

• Carotene

• Hemoglobin

• Albinism: Lack of melanin

Skin Appendages

• Hair: Arrector pili muscle causes hair to stand

• Nails

• Glands:

  • Eccrine sweat: Thermoregulation; simple coiled tubular

  • Apocrine sweat: Axillary/anogenital; body odor

  • Ceruminous: Earwax

  • Sebaceous (oil): Connected to hair follicles; acne

  • Mammary: Modified sweat glands

Bone Tissue

Functions

Bones provide structural support and serve several vital functions.

• Support

• Protection

• Movement

• Mineral storage

• Hemopoiesis (blood cell formation)

Bone Classification

• Long

• Short

• Flat

• Irregular

Long Bone Anatomy

• Diaphysis: Shaft

• Medullary cavity: Contains yellow marrow

• Endosteum: Lines medullary cavity

• Periosteum: Outer fibrous layer, inner osteogenic layer, Sharpey’s fibers

• Epiphysis: Contains red marrow; articular cartilage

• Epiphyseal plate: Growth region

• Epiphyseal line: Remnant of plate

Epiphyseal Plate Zones

• Reserved cartilage

• Proliferating cartilage

• Hypertrophic cartilage

• Calcification/ossification

• Resorption

Compact Bone

• Osteon (Haversian system): Structural unit

• Haversian canal: Contains blood vessels

• Lacunae: Spaces with osteocytes

• Canaliculi: Channels for nutrient/waste exchange

• Volkmann canals: Connect osteons

• Lamellae: Interstitial & circumferential layers

Spongy Bone

• Trabeculae: Lattice-like structures

Bone Composition

• Organic: Collagen fibers for flexibility

• Inorganic: Calcium salts for hardness

Bone Development

• Intramembranous: Direct formation from embryonic fibers

• Endochondral: Indirect formation via hyaline cartilage model

Hormones & Nutrition

• Growth hormone

• Thyroid hormones (T3, T4)

• Sex hormones

• Vitamins & minerals (Ca++, Vit D)

Homeostatic Imbalances

• Osteoporosis: Decreased bone density

• Osteomalacia: Softening of bones in adults

• Rickets: Softening of bones in children

Articulations (Joints)

Joint Classification

Joints are classified by structure and function.

• By Structure (Material): Fibrous, Cartilaginous, Synovial

• By Function (Movement – SAD):

  • Synarthroses (immovable)

  • Amphiarthroses (slightly movable)

  • Diarthroses (freely movable)

Structural Types

• Fibrous: Sutures, syndesmosis, gomphoses

• Cartilaginous: Synchondroses, symphysis

• Synovial: Joint cavity present

Synovial Joint Features

• Articular cartilage

• Synovial cavity

• Synovial capsule (fibrous + synovial membrane)

• Synovial fluid

Associated Structures

• Ligaments

• Menisci

• Bursae

• Tendons

• Tendon sheaths

• Weeping lubrication

Joint Movements

• Nonaxial, uniaxial, biaxial, multiaxial

• Examples: hinge, pivot, ball-and-socket

Angular Movements

• Flexion

• Extension

• Circumduction

• Rotation

Joint Stability Factors

• Ligament strength

• Bone fit

• Muscle tone

Homeostatic Imbalances

• Sprains

• Strains

• Dislocations

• Herniated discs

• Arthritis:

  • Osteoarthritis

  • Rheumatoid arthritis

  • Gouty arthritis

Study tip: Focus on definitions, structures, functions, and comparisons. Diagrams and repetition will help reinforce these concepts for the midterm.