Anatomy & Physiology I: Study Guide – Homeostasis, Organization, Tissues, Integument, and Skeletal System

Homeostasis, Levels of Organization, and Introduction to Anatomy

Key Concepts and Definitions

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of the body and its parts.

• Microscopic Anatomy: Study of structures too small to be seen with the naked eye (e.g., cells, tissues).

• Gross Anatomy: Study of large, visible structures (e.g., organs, organ systems).

• Homeostasis: The maintenance of a stable internal environment despite external changes.

Levels of Organization

• Chemical Level: Atoms and molecules.

• Cellular Level: Cells and their organelles.

• Tissue Level: Groups of similar cells performing a common function.

• Organ Level: Contains two or more types of tissues.

• Organ System Level: Organs that work closely together.

• Organismal Level: All organ systems combined to make the whole organism.

Body Planes and Sections

• Transverse (Horizontal) Plane: Divides the body into superior and inferior parts.

• Frontal (Coronal) Plane: Divides the body into anterior and posterior parts.

• Sagittal Plane: Divides the body into right and left parts. A midsagittal plane divides the body into equal halves.

• Longitudinal Section: A cut along the long axis of a structure.

Directional Terms

• Anterior (ventral): Toward the front of the body.

• Posterior (dorsal): Toward the back of the body.

• Superior: Toward the head or upper part of a structure.

• Inferior: Away from the head or toward the lower part of a structure.

• Medial: Toward the midline of the body.

• Lateral: Away from the midline of the body.

• Proximal: Closer to the origin of the body part or point of attachment.

• Distal: Farther from the origin of a body part or point of attachment.

• Superficial: Toward or at the body surface.

• Deep: Away from the body surface; more internal.

Body Cavities and Membranes

• Major Body Cavities: Cranial, vertebral, thoracic, abdominal, pelvic.

• Serous Membranes: Thin, double-layered membranes that cover surfaces in the ventral body cavity. Includes visceral (covers organs) and parietal (lines cavity walls) layers.

• Pleura: Serous membrane surrounding the lungs.

• Pericardium: Serous membrane surrounding the heart.

• Peritoneum: Serous membrane lining the abdominal cavity and covering abdominal organs.

Abdominal Quadrants and Regions

• Quadrants: Right Upper (RUQ), Left Upper (LUQ), Right Lower (RLQ), Left Lower (LLQ).

• Regions: Epigastric, umbilical, hypogastric, right/left hypochondriac, right/left lumbar, right/left iliac.

Tissues and Histology

Germ Layers

• Ectoderm: Forms skin and nervous system.

• Mesoderm: Forms muscles, bones, and connective tissue.

• Endoderm: Forms lining of digestive and respiratory tracts.

Types of Tissues

• Epithelial Tissue: Covers body surfaces, lines cavities, forms glands.

• Connective Tissue: Supports, protects, and binds other tissues.

• Muscle Tissue: Responsible for movement (skeletal, cardiac, smooth).

• Nervous Tissue: Initiates and transmits electrical impulses.

Epithelial Tissue

• Features: Cellularity, polarity, attachment, avascularity, regeneration.

• Cell Junctions: Tight junctions, desmosomes, gap junctions.

• Classifications: Simple (one layer), stratified (multiple layers), squamous, cuboidal, columnar.

• Specializations: Cilia, microvilli, keratinization.

Connective Tissue

• Components: Cells (fibroblasts, macrophages, adipocytes), fibers (collagen, elastic, reticular), ground substance.

• Types: Loose (areolar, adipose, reticular), dense (regular, irregular, elastic), cartilage (hyaline, elastic, fibrocartilage), bone, blood.

Muscle and Nervous Tissue

• Muscle Types: Skeletal (voluntary, striated), cardiac (involuntary, striated, intercalated discs), smooth (involuntary, non-striated).

• Nervous Tissue: Neurons (transmit impulses), neuroglia (support cells).

Integumentary System

Skin Structure

• Epidermis: Stratified squamous epithelium; layers include stratum basale, spinosum, granulosum, lucidum (in thick skin), corneum.

• Dermis: Papillary (areolar connective tissue) and reticular (dense irregular connective tissue) layers.

• Hypodermis: Subcutaneous layer, mostly adipose tissue.

Functions of the Integument

• Protection, temperature regulation, sensation, metabolic functions, blood reservoir, excretion.

Accessory Structures

• Hair, nails, sweat glands (eccrine, apocrine), sebaceous glands.

Fascia and Membranes

Membrane Types

• Cutaneous Membrane: The skin.

• Mucous Membranes: Line body cavities open to the exterior.

• Serous Membranes: Line closed ventral body cavities.

• Synovial Membranes: Line joint cavities.

Glandular Epithelium

• Exocrine Glands: Secrete products into ducts (e.g., sweat, oil glands).

• Endocrine Glands: Secrete hormones directly into the bloodstream.

• Modes of Secretion: Merocrine (exocytosis), apocrine (pinched off), holocrine (cell rupture).

Bones and Articulations

Bone Structure and Function

• Functions: Support, protection, movement, mineral storage, blood cell formation, triglyceride storage.

• Types of Bones: Long, short, flat, irregular, sesamoid.

• Bone Tissue: Compact (dense) and spongy (cancellous).

• Cells: Osteogenic cells, osteoblasts, osteocytes, osteoclasts.

• Matrix: Collagen fibers, hydroxyapatite (calcium phosphate crystals).

Bone Development and Growth

• Ossification: Endochondral (from cartilage) and intramembranous (from mesenchyme) processes.

• Epiphyseal Plate: Site of bone lengthening during growth.

Bone Markings and Features

• Processes, tuberosities, trochanters, crests, lines, spines, condyles, epicondyles, facets, fossae, sulci, foramina, canals, sinuses.

Joints (Articulations)

• Types: Synarthroses (immovable), amphiarthroses (slightly movable), diarthroses (freely movable).

• Structural Types: Fibrous, cartilaginous, synovial.

• Synovial Joints: Have a joint cavity, articular cartilage, synovial fluid, joint capsule.

• Movements: Flexion, extension, abduction, adduction, rotation, pronation, supination, etc.

Axial and Appendicular Skeleton

Axial Skeleton

• Skull: Cranial and facial bones (frontal, parietal, temporal, occipital, sphenoid, ethmoid, mandible, maxilla, zygomatic, nasal, lacrimal, vomer, palatine, inferior nasal concha).

• Vertebral Column: Cervical (C1–C7), thoracic (T1–T12), lumbar (L1–L5), sacrum, coccyx.

• Thoracic Cage: Sternum, ribs, costal cartilages.

Appendicular Skeleton

• Pectoral Girdle: Clavicle, scapula.

• Upper Limb: Humerus, radius, ulna, carpals, metacarpals, phalanges.

• Pelvic Girdle: Ilium, ischium, pubis, sacrum, coccyx.

• Lower Limb: Femur, patella, tibia, fibula, tarsals, metatarsals, phalanges.

Pelvis and Sexual Dimorphism

• Differences between male and female pelvises (e.g., shape, size, angle of pubic arch).

Sample Table: Types of Epithelial Tissue

Type	Layers	Shape	Location	Function
Simple Squamous	1	Flat	Alveoli, blood vessels	Diffusion, filtration
Simple Cuboidal	1	Cube-like	Kidney tubules, glands	Secretion, absorption
Simple Columnar	1	Tall, column	Digestive tract lining	Absorption, secretion
Stratified Squamous	Multiple	Flat	Skin, mouth, esophagus	Protection
Pseudostratified Columnar	1 (appears multi)	Column	Respiratory tract	Secretion, movement of mucus

Key Formulas and Equations

• Wolff's Law: Bone grows and remodels in response to the forces placed upon it.

• Osmosis (for cell transport):

$J = -P (C_2 - C_1)$

• Where J is the flux, P is the permeability, and C_2 - C_1 is the concentration gradient.

Additional info:

• This study guide is based on a syllabus/term list for an introductory Anatomy & Physiology I course, covering major topics for exam preparation. Students should refer to their textbook and lecture notes for detailed explanations and diagrams.