Human Anatomy Lecture & Lab Notes PDF

LECTURE CHAPTER 1: Anatomy Study of external and internal structures of the body. Examines physical relationships between body parts. Physiology Study of how the body functions. Size of Anatomical Structures Variation: ○ Internal and external structures vary i...

LECTURE CHAPTER 1: Anatomy Study of external and internal structures of the body. Examines physical relationships between body parts. Physiology Study of how the body functions. Size of Anatomical Structures Variation: ○ Internal and external structures vary in size. Types of Anatomical Studies: ○ Microscopic Anatomy ○ Gross Anatomy (Macroscopic Anatomy) Microscopic Anatomy Definition: ○ Study of structures that require magnification to be seen. Subdivisions: ○ Cytology: Study of internal cell structures. ○ Histology: Study of tissues. Gross Anatomy (Macroscopic Anatomy) Definition: ○ Study of structures visible to the naked eye. Subdivisions: ○ Surface Anatomy: Study of superficial anatomical markings. ○ Regional Anatomy: Study of structures in a specific area. ○ Systemic Anatomy: Study of organ systems. Organ Systems of the Body Total: 11 organ systems. Focus: Anatomy and physiology of each system. Levels of Organization 1. Organ Systems: Combinations of various organs. 2. Organs: Combinations of different tissue types. 3. Tissues: Groups of cells. 4. Cells: Smallest living units in the body. The Language of Anatomy Anatomical Position: Standard position for describing anatomical structures. ○ Postural Requirements: Feet flat on the floor. Hands at the sides. Palms facing forward. Anatomical Landmarks Body Regions: ○ Head (11 superficial anatomical landmarks) 1. Cephalon: Head 2. Cranium: Skull 3. Facies: Face 4. Frons: Forehead 5. Nasus: Nose 6. Oculus: Eye 7. Auris: Ear 8. Bucca: Cheek 9. Cervicis: Neck 10. Oris: Mouth 11. Mentis: Chin ○ Trunk ( 7 superficial anatomical landmarks) 1. Thoracis: Chest 2. Mamma: Breast 3. Abdomen: Abdomen 4. Umbilicus: Navel 5. Pelvis: Pelvis 6. Dorsum: Back 7. Lumbus: Loin ○ Upper Limb (11 superficial anatomical landmarks) 1. Shoulder: Shoulder 2. Axilla: Armpit 3. Brachium: Arm 4. Antecubitis: Front of elbow 5. Antebrachium: Forearm 6. Carpus: Wrist 7. Palma: Palm 8. Manus: Hand 9. Pollex: Thumb 10. Digits: Fingers 11. Olecranon: Back of elbow ○ Lower Limb (14 superficial anatomical landmarks) 1. Inguen: Groin 2. Pubis: Pubis 3. Femur: Thigh 4. Patella: Kneecap 5. Crus: Leg 6. Tarsus: Ankle 7. Pes: Foot 8. Planta: Sole of foot 9. Hallux: Big toe 10. Digits: Toes 11. Gluteus: Buttock  12. Popliteus: Back of knee 13. Sura: Calf 14. Calcaneus: Heel of foot Anatomical Directions Right: Right side of the subject Left: Left side of the subject Lateral: Away from midline Medial: Toward midline Proximal: Toward attached base Distal: Away from attached base Superior: Above or toward head Inferior: Below or toward feet Superficial: Near body’s surface Deep: Toward body’s interior Cranial (Cephalic): Toward head Caudal: Toward the tail Posterior (Dorsal): Back Anterior (Ventral): Front Supine: Lying face up Prone: Lying face down Planes and Sections of the Body Plane: Flat, two-dimensional surface. Section: Two-dimensional slice of a three-dimensional structure. Types of Planes: ○ Frontal Plane (Coronal Plane): Separates body into anterior and posterior portions. ○ Sagittal Plane: Separates body into right and left portions.  Midsagittal Section: Divides body into equal right and left halves. Parasagittal Section: Divides body into unequal right and left portions. ○ Transverse Plane (Horizontal/Cross-Sectional Plane): Separates body into superior and inferior portions. LECTURE CHAPTER 2: Cells (fundamental Units of all living things) Types of Cells: ○ Sex Cells (Germ Cells or Reproductive Cells): Contain 23 chromosomes (one copy of each) Males: Sperm Females: Oocytes (eggs) ○ Somatic Cells: All other cells in the body Contain 46 chromosomes (two copies of each 23 chromosomes) Cellular Anatomy Typical Cell Structure: ○ Plasma Membrane: Surrounds the cell. ○ Cytoplasm: Inside the plasma membrane, consisting of: Cytosol: Intracellular fluid Organelles: Intracellular structures with specific functions Plasma Membrane (cell membrane or plasmalemma) Functions of Plasma Membrane: ○ Separates the cell's interior from surrounding extracellular fluid ○ Regulates ion and nutrient entry, waste elimination, and secretory product release ○ Contains receptors for sensing specific molecules and responding to environmental changes ○ Facilitates cell-to-cell communication via special connections Composition of the Plasma Membrane Main Components: ○ Phospholipids: Form a sandwich called the phospholipid bilayer with hydrophilic head and 2 hydrophobic tails. Dissolved ions and water-soluble compounds cannot cross the hydrophobic tails, making the phospholipid bilayer a great physical barrier. ○ Membrane Proteins: Peripheral Proteins: Attached to the inner or outer membrane surface Integral Proteins (Transmembrane Proteins): Embedded in the membrane, can form channels (pores) to allow water-soluble molecules to pass through the plasma membrane or gated channels that open or close to regulate the passage of materials. ○ Glycolipids: Embedded in the membrane, can facilitate cell recognition and communication, stabilize the membrane, and assist in signaling. ○ Sterols: Stabilize membrane structure and maintain fluidity (e.g., cholesterol) Glycoproteins ○ Carbohydrate and lipid components (hybrid molecule), often function as receptors on outer layer of the cell membrane Membrane Permeability Permeability: Ease at which dissolved materials can cross a membrane. ○ Permeability depends on how the lipids and proteins in the membrane are arranged and their specific properties. Selective Permeability: The plasma membrane allows some substances to pass freely while restricting others. Modes of Transport (2 modes) Passive Processes (No energy required): ○ Diffusion: Molecules move from high to low concentration until balanced. ○ Osmosis: Diffusion of water across a selectively permeable membrane, moving from lower to higher solute concentration. ○ Facilitated Diffusion: Solutes are transported across the plasma membrane via carrier proteins, moving along the concentration gradient just like in simple diffusion.  Active Processes (Require ATP or other energy sources): ○ Active Transport: Moves molecules against their concentration gradient using energy ○ Endocytosis: Process of cells engulfing external substances to bring them inside Pinocytosis: Cell drinking (engulfs liquid from its surrounding) Phagocytosis: Cell eating (engulfs large particles like debris or microorganisms) Receptor-Mediated Endocytosis: Specific molecule uptake ○ Exocytosis: Expulsion/ejection of materials from the cell Extensions of the Plasma Membrane Microvilli: extensions of plasma membrane. ○ Small, finger-shaped projections of the plasma membrane ○ Increase surface area for absorption. Found on cells that function to absorb. ○ Supported by the cytoskeleton Cytoplasm (general term for all material aka fluid found in the cell) Components: ○ Cytosol: Intracellular fluid ○ Organelles: Intracellular structures that have specific functions within the cell Nonmembranous Organelles (Not surrounded by membranes) Cytoskeleton: Internal framework of fibers that maintain cell structure, includes 4 components: ○ Microfilaments; thin strands ○ Intermediate Filaments; medium fibers ○ Thick Filaments; thick strands myosin ○ Microtubules; hollow tubes Centrioles: Organize microtubules in spindle to separate chromosomes during cell division  Cilia: Hair like structures that beat rhythmically to move fluids or secretions across the cell surface Flagella (sperm): Long projections for cell movement through the surrounding fluid Ribosomes: Protein manufacturing organelles ○ Free Ribosomes: Scattered in cytosol ○ Attached Ribosomes: attached to the endoplasmic reticulum Membranous Organelles (surrounded by membranes, separating contents from cytosol) Mitochondria: ○ Two membranes (inner and outer) ○ Produce ATP by breaking down glucose Nucleus: ○ Stores and controls genetic material (DNA) ○ Nuclear envelope: Double-membraned organelle surrounds the nucleus, contain channels called nuclear pores (small openings in the nuclear membrane that allow materials to move in and out of the nucleus) ○ Nucleoplasm: Jelly-like fluid inside nucleus ○ Nucleolus: Clear organelles that synthesizes ribosome components Endoplasmic Reticulum: ○ Network with or without ribosomes ○ Functions: Lipid (smooth), protein (rough), and carbohydrate synthesis; synthesized molecule storage; transport molecules within cells; detoxification of drugs and toxins. Golgi Apparatus: ○ Flattened membrane discs (cisternae) ○ Functions: Packages enzymes, renews/modifies plasma membrane, synthesizes and packages secretions. Lysosomes: ○ Vesicles formed from the Golgi apparatus. ○ Functions: Defend against microbes, activate enzymes for digestion. ○ Primary lysosomes contain inactive enzymes. Secondary lysosomes form when a primary lysosome fuses with another vesicle, activating the enzymes. Peroxisomes: ○ Vesicles smaller than lysosomes ○ Functions: Carry enzymes that remove & neutralize toxins Intercellular Attachments Cell Junctions: Parts of plasma membrane that link a cell to other cells or materials outside. ○ Gap Junctions: Narrow passageways for small molecules and ions. ○ Tight Junctions: Prevent fluid and solute passage between cells. ○ Desmosomes: Cell structures that join adjacent cells together, providing strength and stability to tissues. Can resist stretching and twisting. Spot Desmosomes: Connect cells with CAMs attached to intermediate filaments. Hemidesmosomes: Attach cells to extracellular filaments in the basement membrane. LAB 1 (CHAPTER 6): Bone Markings: Distinctive features on the bone surface. Types of Bone Markings 1. Process: A projection or bump on the bone. 2. Foramen: A passageway for blood vessels and nerves. Human Skeleton Adult human skeleton consists of 206 bones. It is divided into two main sections/divisions: 1. Axial Division 2. Appendicular Division Axial Division It’s composed of 80 bones. These bones are divided into 3 components: 1. Skull and Associated Bones (29) 2. Thoracic Cage (25) 3. Vertebral Column (26) Skull and Associated Bones The skull and associated bones consist of 29 bones in total. 1. Skull (Further divided into): Facial Bones (14 bones): 1. Maxillae: Upper jawbones 2. Palatine Bones 3. Nasal Bones 4. Inferior Nasal Conchae 5. Zygomatic Bones: Cheekbones 6. Lacrimal Bones: Small bones in the inner corner of the eyes 7. Vomer 8. Mandible: Lower jawbone Cranial/ Skull Bones (8 bones): 1. Occipital Bone: Bone at the back of the skull 2. Parietal Bones (2): Bones on the top and sides of the skull  3. Frontal Bone: Forehead bone 4. Temporal Bones (2): Bones on the sides of the skull 5. Sphenoid Bone: Bone at the base of the skull, in front of the temporal bones 6. Ethmoid Bone: Bone between the eyes, forming part of the nasal cavity 2. Associated Bones: Hyoid Bone (1): U-shaped bone in the neck that supports the tongue Auditory Ossicles (6): Tiny bones in the middle ear that help transmit sound from the eardrum to the inner ear. Facial Bones Maxillae: Forms the upper jaw. Zygomatic Bone: Forms the anterior portion of the cheekbones.  Lacrimal Bones: Contributes to the orbits of the eye. (before the ethmoid) Mandible: Forms the lower jaw. Cranial Bones (Skull) Occipital Bone: Creates the rounded posterior surface of the skull; forms the posterior, lateral, and inferior surfaces of the cranium. Parietal Bones (2): Form most of the superior and lateral surfaces of the cranium.  Frontal Bone: Forms the forehead. Temporal Bones (2): Located on the lateral sides of the skull; contribute to the cheekbones. Sphenoid Bone: Complex shape; comes into contact with all bones of the cranium.  Ethmoid Bone: Complex shape; part of the cranial structure. Associated Bones of the Skull Hyoid Bone: Located in the neck. Auditory Ossicles: Small bones in the middle ear. LAB 2 (CHAPTER 2&6) Cell and Organelle Sizes: Human Cells: ○ Diameter: 7 µm to 150 µm (micrometers) ○ Average Size: 10-15 µm ○ Not visible to the naked eye. Organelles: ○ Diameter: 20 nm to 10 µm ○ Not visible to the naked eye. Microscope Requirements: ○ Light Microscope: For structures in the mm to µm range. ○ Electron Microscope: For structures in the nm range. Light Microscope Parts: Ocular Lens (Eyepieces): Lenses you look through to see the specimen. Nosepiece: Holds and rotates the objective lenses. Objective Lens: Lenses with different magnifications that zoom in on the specimen. Observation Tube: The part you look through, which connects the ocular lens to objective lenses. Tube Clamping Screw: Holds the observation tube in place, can loosen or tighten to change. Stage: Platform where the specimen slide is placed. Stage Clip: Holds the slide in place on the stage. Iris Diaphragm: Adjusts the amount of light that reaches the specimen. Light Source: Provides illumination to view the specimen. Coarse Focus Knob: Adjusts the focus roughly to bring the specimen into view. Fine Focus Knob: Makes small adjustments to sharpen the focus. X-axis Stage Knob: Moves the slide left and right. Y-axis Stage Knob: Moves the slide up and down. Light Intensity Control Knob: Adjusts the brightness of the light source. Power Switch: Turns the microscope on or off. Magnification vs. Resolution: Magnification: Makes an object appear larger or smaller than its actual size, allowing more detail to be seen. Resolution: The ability of a microscope to distinguish details of a specimen. Vertebral Column Composed of 26 bones: ○ 24 Vertebrae: 7 Cervical Vertebrae 12 Thoracic Vertebrae 5 Lumbar Vertebrae ○ 1 Sacrum ○ 1 Coccyx Functions of the Vertebral Column Encloses and protects the spinal cord. Supports the skull. Supports the weight of the head, neck, and trunk. Transfers weight to the lower limbs. Helps maintain the upright position of the body. Vertebral Regions Cervical (C1 - C7) Thoracic (T1 - T12) Lumbar (L1 - L5) Sacral Coccygeal Typical Vertebral Anatomy Vertebral Body Spinous Process Vertebral Foramen Cervical Vertebrae (7) 7 cervical vertebrae. Support the weight of the head. 2 vertebrae have specific names: 1. C1 is the Atlas 2. C2 is the Axis  Atlas (C1) Characteristics: No vertebral body or spinous process; has largest vertebral foramen. Axis (C2): Has the dens, a projection formed from the fusion of the atlas and axis. Characteristics: ○ Vertebral body is small and oval-shaped. ○ Have a bifid top of their spinous process. ○ Have transverse foramina. ○ Have transverse processes that project laterally from the vertebral body. Thoracic Vertebrae 12 thoracic vertebrae. Connect to the ribs and support them. Characteristics: ○ No bifid tip on the spinous process. ○ Heart-shaped vertebral body. ○ Transverse processes project laterally from the anterior of the vertebral body. ○ Spinous process points inferiorly. ○ No transverse foramina. Lumbar Vertebrae 5 lumbar vertebrae. Support the weight of the torso. Characteristics: ○ Large vertebral body. ○ Broad tip on spinous process points posteriorly. ○ Smallest vertebral foramen. Sacrum and Coccyx Sacrum: one bone consisting of 5 fused vertebrae. ○ Coccyx: Consists of three to five fused vertebrae (difference between children and adults) ○ Adult male coccyx points anteriorly. ○ Adult female coccyx points inferiorly. LECTURE 3 (CHAPTER 3) Tissues Tissues are groups of specialized cells that work together to perform specific functions. Histology is the study of tissues. Four primary tissue types: ○ Epithelial tissue ○ Connective tissue ○ Muscle tissue ○ Nervous or neural tissue Epithelial Tissue Definition: Epithelial tissue (epithelia or epithelium) consists of sheets of cells that cover exposed body surfaces and line internal cavities and passageways. Functions: Protect surfaces Control permeability Provide sensation Produce specialized secretions Characteristics: Avascularity: Epithelial tissue lacks blood vessels. Stem Cell Regeneration: Stem cells work to continuously replace damaged or lost surface cells. Cell Arrangement (junctions): Cells are tightly bound by specialized junctions, with little/no intercellular space. Polarity: Has an exposed apical surface facing the exterior or internal space, and a basolateral (basal) surface attached to adjacent tissues. These surfaces caused cells to have polarity. Basement Membrane: Basolateral surface of the epithelial cells are bound to a thin basement membrane. It is composed of: ○ Basal Lamina: Restricts movement of large molecules into epithelial tissue. ○ Reticular Lamina: Anchors the basement membrane to underlying tissues. Structure: Epithelial tissue is organized in one or more layers of cells. Classification: Number of Layers: ○ Simple: Single layer of cells. ○ Stratified: Multiple layers of cells. Cell Shape: ○ Squamous: Thin, flat and irregular cells. Looks squashed like a plate/scale. ○ Cuboidal: Cube-shaped cells and appear square in typical sectional views. Each nuclei is centrally located. ○ Columnar: Tall and rectangular cells. Nuclei are typically located within the basal portion of the cells. Types of Epithelial Tissue: Simple Epithelium: ○ One cell layer attached to the basement membrane. ○ All cells have the same polarity, so the nuclei form a row at the same distance from the basement membrane. Stratified Squamous Epithelium: ○ Two or more cell layers. ○ The height and shape of the cells differ from layer to layer; therefore, we only use the shape of the most superficial layer for epithelium classification. Specialized Epithelial Tissue: Pseudostratified Ciliated Columnar Epithelium Transitional Epithelium Glandular Epithelial Tissue: Many epithelial tissues contain gland cells Gland cells are epithelial cells that produce secretions Types of Secretions: ○ Exocrine Glands: Release secretions onto epithelial surfaces through ducts. Serous glands: Watery, enzyme-containing secretion. Mucous glands: Viscous, mucin-containing secretion. Mixed Exocrine glands: Contains multiple types of gland cells. ○ Endocrine Glands: Ductless, release hormones directly into the bloodstream. Gland Structure: ○ Simple Glands: Non-branching or minimally branching. ○ Compound Glands: Repeatedly branching. Methods of Secretion: ○ Eccrine (Merocrine): Release via exocytosis without loss of cell material. ○ Apocrine: Release involves part of the cell; partial cell loss. ○ Holocrine: Release involves the entire cell; entire cell disintegration. Connective Tissue: Definition: Connective tissue is widespread in the body with various functions, including structural support, fluid transport, protection, and energy storage. Components: Specialized Cells Extracellular Protein Fibers Ground Substance: Fluid surrounding the cells, together with extracellular protein fibers forming the extracellular matrix. Functions: (no single category of connective tissue performs all functions) Structural framework for the body Transport fluids and dissolved materials throughout body Organ protection Support, surround, and interconnect other tissue types Energy storage, especially in the form of lipids Defense against microorganisms Classification of Connective Tissues Proper: Specialized Cells of Connective Tissue Proper: Fixed Cells: Stationary cells involved in local maintenance, repair, and energy storage. Examples include fibroblasts (produce and maintain extracellular matrix) and adipocytes (store fat). Wandering Cells: Mobile cells that assist in defending and repairing damaged tissues. Examples include macrophages (engulf and digest foreign particles) and mast cells (release histamine and other chemicals in inflammatory responses). Extracellular Fibers of Connective Tissue Proper Collagen Fibers: The strongest and most common type; long, straight, and unbranched. Reticular Fibers: Form a branching, interwoven network that supports the structure. Elastic Fibers: Branching and wavy, providing elasticity and flexibility. Ground Substance of Connective Tissue Proper Composition: Clear, colorless, and similar in consistency to maple syrup. It contains hyaluronan, proteoglycans, and glycoproteins. Function: Surrounds cellular and fibrous components. Connective Tissue Proper (2 types) Loose Connective Tissue: "packing material" of the body, filling spaces and providing cushioning. ○ Areolar Tissue: Contains various cells and fibers, with a loose framework allowing distortion without damage; supports & cushions organs. The nuclei in fibrocysts (fluid-filled sacs in the breast tissue) can appear larger and more irregular compared to normal cells. ○ Adipose Tissue: Composed primarily of adipocytes, with yellow/white fat (cushions and insulates) and brown fat (highly vascularized, generates heat); stores lipids and insulates body. ○ Reticular Tissue: Contains reticular fibers forming a supportive network (found in liver, kidney, spleen, lymph nodes, bone marrow) Dense Connective Tissue(collagenous tissue): ○ Dense Regular: Collagen fibers aligned parallel to direction that force is applied; found in tendons, aponeuroses, elastic tissue and ligaments.  ○ Dense Irregular: Collagen fibers form an interwoven network; supports areas subjected to multi-directional stress. Fluid Connective Tissue Blood: Contains cells, extracellular fibers, and a watery ground substance; contained in the cardiovascular system. Lymph: Similar to blood but lacks red blood cells and contains fewer proteins; contained in the lymphatic system. Supporting Connective Tissues Cartilage: Firm and rubbery matrix with chondroitin sulfates; cartilage cells are called chondrocytes. ○ Hyaline Cartilage: Most common, with closely packed collagen fibers (nose, trachea, larynx) ○ Elastic Cartilage: Contains elastic fibers, providing flexibility. ○ Fibrous Cartilage: Dominated by collagen fibers, with little ground substance.  Bone: Solid and crystalline matrix; matrix of collagen fibers and calcium salts ○ Spongy bone: Light and porous, found at the ends of long bones. ○ Compact bone: Dense and forms the outer layer of bones. Membranes Definition: Combinations of epithelial and connective tissues that protect other structures. Muscle Tissue Types: ○ Skeletal Muscle: Voluntary, striated muscle attached to bones. ○ Cardiac Muscle: Involuntary, striated muscle found in the heart. ○ Smooth Muscle: Involuntary, non-striated muscle found in walls of organs and vessels. Nervous (Neural) Tissue Types: ○ Neurons: Specialized cells for transmitting nerve impulses. ○ Neuroglia: Supportive cells that assist and protect neurons. LAB 3 - Histology and Thoracic Cage Thoracic Cage Components: ○ The adult vertebral column is made up of 25 bones: 1 sternum 24 ribs Functions: ○ Protects the heart, lungs, thymus, and other structures within the thoracic cavity. ○ Serves as the attachment site for muscles involved in: Respiration Positioning the vertebral column Movements of the pectoral girdle and upper limbs Sternum: ○ Forms the breastbone. ○ Has depressions on its lateral surface where the ribs connect. Ribs: 12 pairs (24 rib bones) ○ 3 Classifications: Vertebrosternal Ribs (1–7): Connect to the sternum via costal cartilages. Vertebrochondral Ribs (8–10): Connect indirectly to the sternum via costal cartilages. Vertebral Ribs (Floating Ribs) (11–12): No anterior cartilage attachment. LECTURE 4 (Integumentary System) Components of the Integumentary System The integumentary system consists of two major components: 1. Cutaneous Membrane ○ Epidermis ○ Dermis 2. Accessory Structures ○ Hair Follicles ○ Exocrine Glands ○ Nails Cutaneous Membrane The cutaneous membrane is composed of: 1. Epidermis 2. Dermis ○ Papillary Layer ○ Reticular Layer Epidermis (Cutaneous Membrane) Structure: Composed of stratified squamous epithelium. Cell Types: 1. Keratinocytes: Produce keratin. 2. Melanocytes: Produce melanin. 3. Merkel Cells: Sensory touch receptors. 4. Langerhans Cells: Immune response. Layers of the Epidermis: 1. Stratum Basale ○ Deepest epidermal layer ○ Single layer of cells. ○ Predominantly basal cells (stem cells). ○ Contains scattered melanocytes and Merkel cells amongst basal cells. 2. Stratum Spinosum ○ Several cell layers thick. ○ Basal cells divide and differentiate into keratinocytes. ○ Contains melanocytes and Langerhans cells. 3. Stratum Granulosum ○ Keratinocytes manufacture keratohyalin and keratin. 4. Stratum Lucidum ○ Cells lack organelles and nuclei. ○ Cells are flattened and densely packed. ○ Keratin filaments are oriented parallel to the surface of skin. 5. Stratum Corneum ○ Most superficial layer AND consists of numerous layers of flattened, dead cells. ○ Cells possess a thickened plasma membrane. ○ Epithelial cells with large amounts of keratin are called keratinized epithelium. Thin and Thick Skin Thin Skin: ○ Has only four epidermal layers (lacks the stratum lucidum). ○ The stratum corneum is thinner. Thick Skin: ○ Contains all five epidermal layers. ○ The stratum corneum can be up to 30 or more cell layers thick. Dermal Ridges Formed by the stratum basale. Dermis forms projections called dermal papillae that extend between adjacent ridges. Increases the area of contact between the epidermis and dermis, enhancing skin strength and resilience. Skin Color Determined By: 1. Circulation to the Dermis 2. Epidermal Pigments: Carotene: Contributes to yellowish hue. Melanin: Contributes to pigmentation ranging from yellow to brown to black. Dermis (Cutaneous Membrane) Location: Deep into the epidermis. Layers: 1. Papillary Layer: Loose connective tissue. 2. Reticular Layer: Dense irregular connective tissue. Surrounds accessory structures. Subcutaneous Layer (Hypodermis) Location: Deep under the dermis. Composition: Loose connective tissue with abundant adipocytes (fat cells). Accessory Structures 1. Hair Follicles ○ Extend deep into the dermis and often into the subcutaneous layer. ○ Connected to the arrector pili muscle, which raises the hair follicle when stimulated. 2. Exocrine Glands ○ Sebaceous Glands: Produce sebum (a waxy, oily lipid). Sebum coats hair shafts and the epidermis. Sebaceous follicles secrete sebum directly onto the skin. ○ Sweat Glands: Produce a watery solution. Contain myoepithelial cells that contract to squeeze the gland and release its secretions. Types: Apocrine Sweat Glands: Found in armpits, nipples, and groin. Release a viscous, cloudy, and potentially odorous secretion. Sweat serves as a nutrient source for bacteria, intensifying odor. May contain pheromones. Eccrine Sweat Glands: Smaller and do not extend as far into the dermis. Produce a clear secretion called sweat or sensible perspiration. LAB 4 (Integumentary System) & LAB 5 (Carpal bones, metacarpals, and phalanges) Histology of the Cutaneous Membrane Epidermis Type: Stratified squamous epithelium Dermis Papillary Layer: Loose connective tissue Reticular Layer: Dense irregular connective tissue Hypodermis (Subcutaneous Layer) Type: Loose connective tissue with abundant adipocytes Layers of the Epidermis 1. Stratum Basale Location: Deepest epidermal layer, rests on the basement membrane Composition: Single layer of large stem cells (basal cells) Cell Shape: Cuboidal or columnar 2. Stratum Spinosum Location: Superficial to the stratum basale Composition: Several cell layers thick Function: Basal cells divide and differentiate into keratinocytes, which migrate superficially 3. Stratum Granulosum Location: Superficial to the stratum spinosum Composition: Thin layer where cells become flatter and more irregular Function: Keratinocytes manufacture keratohyalin granules; cells stain dark purple or blue 4. Stratum Lucidum Location: Superficial to the stratum granulosum Composition: Cells lack organelles and nuclei, are flattened and irregular Function: Cells are densely packed with protein called eleidin 5. Stratum Corneum Location: Most superficial layer of the epidermis Composition: Numerous layers of flattened, dead cells Function: Cells contain large amounts of keratin Thin vs. Thick Skin Thin Skin Layers Present: Stratum corneum, stratum granulosum, stratum spinosum, stratum basale Stratum Corneum Thickness: Only a few cell layers thick Thick Skin Layers Present: All five epidermal layers including the stratum lucidum Stratum Corneum Thickness: 30 or more cell layers thick Histology of the Dermis Papillary Layer Type: Loose connective tissue Characteristics: Fibers create a loose and open framework Reticular Layer Type: Dense irregular connective tissue Characteristics: Fibers form an interwoven meshwork without a consistent pattern Histology of Hypodermis Type: Loose connective tissue with abundant adipocytes Histology of Accessory Structures Arrector Pili Muscle Location: Originates in the papillary layer of the dermis Function: Connects to hair follicle and raises the hair when stimulated Sebaceous Glands Association: Often connected with hair follicles Function: Produce sebum, which coats hair shafts and the epidermis Bone Markings Spine: Sharp, slender projection Fossa: Shallow depression or indentation Head: A type of process, expanded projection at the end of long bones Pectoral Girdle 1. Clavicle (Collarbone) 2. Scapula (Shoulder Blade) Upper Limb Bones 1. Humerus (Bone of the brachium aka. arm) 2. Radius and Ulna (Bones of the antebrachium aka. forearm) 3. Carpal Bones (small hand bones)  4. Metacarpals 5. Phalanges LECTURE 5 (Skeletal System) Skeletal System Overview Components: Bones Cartilages Ligaments Connective tissues stabilizing or interconnecting bones Functions: 1. Support: Provides structural framework for the body. 2. Mineral Storage: Stores calcium. 3. Blood Cell Production: Bone marrow houses stem cells that produce all blood cells. 4. Protection: Shields delicate organs. 5. Leverage: Bones act as levers for muscles to facilitate muscle contraction mechanics. Connective Tissue Components: 1. Specialized Cells 2. Extracellular Protein Fibers 3. Ground Substance: Extracellular fluid surrounding the cells. Extracellular Matrix: Consists of extracellular protein fibers and ground substance. Supporting Connective Tissue Categories of Supporting Connective Tissues: 1. Cartilage 2. Bone (Osseous Tissue) Specialized Bone Cells (4): Osteoprogenitor Cells: Stem cells differentiating into other bone cells. Osteocytes: Mature bone cells. Osteoblasts: Secrete osteoid (bone ground substance); responsible for new bone production. Osteoclasts: Large, multinucleate cells that erode bone (a process called osteolysis). Extracellular Matrix of Bone: Collagen Fibers: make up 1/3 of the matrix. Calcium Phosphate: make up 2/3 of the matrix; crystallizes to solidify the matrix. Types of Bone Compact Bone: Characteristics: Dense and solid. Functional Unit: Osteon ○ Concentric Lamellae: Form rings of mineralized collagen fibers and calcium salts. ○ Lacunae: Small spaces housing osteocytes. ○ Canaliculi: Interconnected junctions in extracellular matrix. ○ Central Canal: Channel for blood vessels. Other Structures: ○ Interstitial Lamellae: Collagen fibers and calcium salts that fill spaces between osteons. ○ Circumferential Lamellae: Mineralized collagen fibers and calcium salts found at external surfaces of bone. ○ Perforating Canals: Perpendicular canals for blood vessels supplying deeper osteons. Spongy Bone: Structure: Branching plates called trabeculae. Contains: Lamellae (mineralized collagen fibers and calcium salts) ○ Lamellae form osteons if there are enough layers. ○ Lamellae have lacunae where osteocytes reside. ○ Lacunae are connected by canaliculi. Function: Forms an open network, honeycomb-like. Anatomy of Long Bones Epiphysis: Ends of long bones. Diaphysis: Shaft of long bones. Metaphysis: Region between the epiphysis and diaphysis. Medullary Cavity: Cavity in the middle containing bone marrow. ○ Yellow Marrow: Adipocytes. ○ Red Marrow: Red and white blood cells, and stem cells producing them. Compact Bone: Lines the superficial layer and medullary cavity. Spongy Bone: Fills the epiphyses. Periosteum (the outer sheath of bones, providing blood, nerves, and growth-repair cells) Location: Covers the outer surface of bones. Exclusions: Not present where tendons, ligaments, joint capsules attach, or where bone surfaces are covered by cartilage. Periosteum consists of two layers: 1. Fibrous Layer: Dense connective tissue. 2. Osteogenic Layer: Contains osteoprogenitor cells. Endosteum (lines inner surfaces) Location: Lines the medullary cavity and inner surfaces of central and perforating canals. Characteristics: ○ One cell layer thick. ○ Incomplete cell layer. ○ Contains osteoprogenitor cells, osteoclasts, and osteoblasts. ○ Active during bone growth, repair and remodeling. Bone Development and Growth Osteogenesis: Process of bone formation and growth. Embryonic Development: Skeletal elements initially composed of mesenchyme or hyaline cartilage during embryonic development. Ossification: Replacement of mesenchyme or cartilage with bone once the embryo develops. 2 Types of Ossification: 1. Intramembranous Ossification (dermal ossification): bone develops from mesenchyme ○ Occurs in deeper layers of the dermis. ○ The bones that result are called membrane bones or dermal bones. ○ Examples: Frontal, parietal, occipital bones, mandible. ○ Mesenchymal tissue is replaced with bone in FOUR steps: Mesenchymal cells differentiate into osteoblasts. Osteoblasts aggregate and secrete osteoid.  Osteoid mineralizes and undergoes ossification. The location where ossification begins is called ossification center. Osteoblasts differentiate into osteocytes. Osteocytes become trapped in the lacunae in the bone matrix. Spicules (small projections) grow outward from ossification centers. Blood vessels get trapped in merging spicules. Spicules merge and form a bony plate that becomes a spongy bone. Spongy bone can be remodeled into compact bone. 2. Endochondral Ossification: bone develops from hyaline cartilage ○ Hyaline cartilage is replaced by bone. ○ Bones Formed: Limbs and other long bones. ○ Endochondral Ossification occurs in 7 Steps: (steps 1-4 initiates ossification of the developing bone and steps 5-7 increase the length of the developing bone) 1. Chondrocytes at the center increase in size, and the extracellular matrix calcifies. Chondrocytes deep in the tissue die of nutrient deprivation due to lack of blood supply. 2. Blood vessels grow around edge of cartilage; perichondrium becomes periosteum. Osteogenic layer of the periosteum forms a bone collar (thin layer of compact bone around the shaft of the cartilage). 3. Blood supply and osteoblasts migrate into the cartilage center (osteoblasts occupy spaces left by dead chondrocytes). Cartilaginous matrix is broken down, replaced with spongy bone by the osteoblasts.  Regions where bone is developed by osteoblasts is called primary ossification center. Bone is replaced from the middle of the shaft towards the ends of the cartilage. 4. Medullary (marrow) cavity formation as the shaft diameter increases. 5. Secondary ossification centers form in epiphyses by blood supply and osteoblasts. 6. Osteoblasts replace cartilage matrix in epiphyses (ends of bone) into spongy bone. Epiphysis (end) and diaphysis (shaft) are separated by narrow epiphyseal cartilage. As we grow, chondrocytes (cartilage cells) in the epiphyseal cartilage keep dividing and growing, moving toward the diaphysis. Chondrocytes start to degenerate and die as they migrate to the diaphysis. Osteoblasts (bone-forming cells) occupy lacunae and fill the spaces left by dying chondrocytes and replace cartilage with bone. 7. As we age, the growth of epiphyseal cartilage at the ends of bones slows down and bone-forming cells (osteoblasts) activity increases. Therefore, the epiphyseal cartilage gets narrower and narrower until it disappears in an event called epiphyseal closure. The former location of the epiphyseal cartilage becomes a distinct epiphyseal line that remains after growth has ended. The area where the cartilage used to be becomes a distinct epiphyseal line, marking the end of bone growth. Bone Growth (bones can grow in 2 distinct processes) Increase in Length: Continued growth of epiphyseal cartilage and replacement of degenerating chondrocytes. Increase in Diameter (Appositional Growth): Osteoprogenitor cells in the periosteum differentiate into osteoblasts, adding bone matrix to surface. At the same time, osteoclasts in the endosteum reabsorb bone matrix. This results in medullary cavity enlargement and increased bone diameter. LECTURE 6 - JOINTS Overview of the Skeletal System Comprises bones, cartilages, ligaments, joints, and other connective tissues that stabilize or connect bones. Joints (articulations) Definition: Junctions between two or more bones. Function: The anatomy of a joint determines its function and range of motion. Classification of Joints: Histological Structure Fibrous Joints: Bones attached by collagenous connective tissue. Cartilaginous Joints: Bones attached by hyaline or fibrous cartilage. Synovial Joints: Freely movable joints with a fluid-filled cavity to reduce friction. Range of Motion Synarthrosis: Immovable joints. Amphiarthrosis: Slightly movable joints. Diarthrosis: Freely movable joints. Types of Joints Fibrous Joints: Bones joined together by fibrous connective tissue. Types: 1. Sutures: Synarthroses located between skull bones; edges of the bone interlock and are bound by dense fibrous tissue called sutural ligament. 2. Gomphosis: Specialized synarthroses binding teeth to their bony sockets via the fibrous tissue called periodontal ligament. 3. Syndesmosis: Amphiarthroses are ligaments that connect bones together (e.g., radius and ulna). Cartilaginous Joints: Bones joined by cartilage or fibrous cartilage. Types: 1. Synchondrosis: Synarthroses made of hyaline cartilage; can be temporary (ossify into bone) or permanent (e.g., ribs to sternum). The hyaline cartilage of temporary synchondroses ossify into bone and are referred to as synostoses (e.g, epiphyseal line). 2. Symphysis: Amphiarthroses with a pad of fibrous cartilage (e.g., joint between hip bones). Synovial Joints: Diarthroses; main functional joints of the body. They can be found at the end of long bones of the upper and lower limbs. Basic components: 1. Joint capsule 2. Articular cartilage 3. Joint cavity filled with synovial fluid 4. Synovial membrane lining the joint capsule 5. Accessory structures (cartilage & fat pads, ligaments, tendons, bursae) Synovial Joint Classification Types: 1. Plane/Gliding Joint (allows sliding like wrist) 2. Pivot Joint (allows rotation like neck) 3. Saddle Joint (allows for opposition) 4. Hinge Joint (allows bending & straightening) 5. Condylar Joint (allows movement in 2 planes) 6. Ball-and-Socket Joint (allows multi-directions) Types of Movement Angular Motion Abduction: Movement away from the body. Adduction: Movement toward the body. Flexion: Decreases the angle between bones. Extension: Increases the angle between bones. Hyperextension: Extending beyond normal limits. Circumduction: Moving arm in a circular motion. Rotation Left/Right Head Rotation: Movement of head & limbs. Internal (medial) Rotation: Rotating the limb inward. External (lateral) Rotation: Rotating the limb outward. Pronation: palm-facing-front to palm-facing-back Supination: palm-facing-back to palm-facing-front Special Movements Eversion: Sole of the foot turns outward. Inversion: Sole of the foot turns inward. Dorsiflexion: Toes up, elevation of the distal portion of the foot and the toes. Plantarflexion: Toes down, elevation of the heel and proximal portion of the foot. Lateral Flexion: Bending the spine to the side. Protraction: Moving part of body anteriorly in horizontal plane (forward) Retraction: Moving part of the body posteriorly in the horizontal plane (backward) Opposition: Thumb touches other fingers. Reposition: Return thumb and fingers to their normal position. Elevation: Structure moves in a superior direction (up) Depression: Structure moves in an inferior direction (down) Notable Joints Glenohumeral Joint: Ball-and-socket joint between the head of humerus and glenoid fossa of scapula. Ligaments: Coracohumeral, coracoacromial, acromioclavicular, coracoclavicular, transverse humeral. Knee Joint: Complex joint between the femur, tibia, and patella. Supporting Ligaments: 1. Patellar ligament 2. Medial collateral ligament 3. Lateral collateral ligament 4. Popliteal ligaments 5. Anterior cruciate ligament (ACL) 6. Posterior cruciate ligament (PCL) LAB 6 (LOWER LIMBS) Appendicular Division 1. Pectoral Girdle 2. Upper Limbs 3. Pelvic Girdle 4. Lower Limbs Bone Markings Spine: Sharp, slender projection Fossa: Shallow depression or indentation Head: Expanded projection at the end of an epiphysis Linea: Subtle, long, narrow projection Pelvic Girdle Components: Hip Bone (Pelvis) Identifying Left vs. Right Hip Bone Acetabulum: Located laterally Posterior Superior Iliac Spine: Located posteriorly Positioning: ○ If the acetabulum is on the right, it's the right hip bone. ○ If the acetabulum is on the left, it's the left hip bone. Lower Limbs 1. Femur 2. Patella (Kneecap) 3. Tibia 4. Fibula 5. Tarsal Bones 6. Metatarsals 7. Phalanges Femur: The largest bone in the body (thigh bone) Identifying Position: ○ If the head is on the right, it's the left femur. ○ If the head is on the left, it's the right femur. Patella: The kneecap Tibia and Fibula: Bones of the crus (leg) Tibia: Medial bone Fibula: Lateral bone Tarsal Bones (Ankle Bones) Total Bones: 7 1. Talus 2. Calcaneus 3. Navicular 4. Medial Cuneiform 5. Intermediate Cuneiform 6. Lateral Cuneiform 7. Cuboid Metatarsals: Labeled with Roman numerals I-V. Phalanges (Toe Bones) Structure: Each phalanx has three phalanges (proximal, middle, distal), except for the hallux (big toe), which has two (proximal and distal).