Midterm 1 Tissues PDF

4.1 Introduction to Tissues Tissue—........ Histology—The study of the normal structure of tissues All tissues share 2 basic components: – A discrete population of cells that are related in structure and function – The surrounding material, called Extracellular Matrix (EC M),...

4.1 Introduction to Tissues Tissue—........ Histology—The study of the normal structure of tissues All tissues share 2 basic components: – A discrete population of cells that are related in structure and function – The surrounding material, called Extracellular Matrix (EC M), which does differ in composition in each tissue type 4.1 Types of Tissues There are 4 Primary Tissue Types 1..... Tissues—Sheets of tightly packed cells with little EC M; Covers and lines body surfaces and cavities and form parts of glands 2..... Tissues—Connect all other tissues together; Cells are scattered through the EC M; Bind, support, protect, and allow transport of substances 3..... Tissues—Cells contract and generate force; Little EC M 4...... Tissues—Cells (Neurons) generate, send, and receive messages; Includes cells that support the neurons with some EC M Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.1 Extracellular Matrix (1 of 4) Extracellular Matrix —Composed of substances surrounding the cells in a tissue that function to: Provide the tissue with strength to resist tensile (stretching) and compressive forces Direct cells to their proper places within a tissue Regulate the development, mitotic activity, and survival of cells Hold cells in their proper positions EC M has 2 main components: Ground Substance and Protein Fibers Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.1 Extracellular Matrix (2 of 4) Ground Substance—Gel-like substance that contains extracellular fluid (EC F) with water, ions, nutrients, and other solutes, and 3 families of macromolecules: Glycosaminoglycans (G AG s) —are carbohydrate polymers that attract water and form a gel-like substance in the ECM, providing hydration and cushioning (ex. Hyaluronic Acid). Proteoglycans—large molecules with GAG chains attached to a core protein, contributing to tissue structure, cell signaling, and ECM organization. Act as a barrier to diffusion of substances through the EC M (ex. Aggrecan). Glycoproteins—are proteins with carbohydrate chains that play roles in cell adhesion, matrix formation, and signaling (ex. Fibronectin). Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.1 Extracellular Matrix (3 of 4) Protein Fibers—Entwined fibrous protein subunits that provide tensile strength; Three types are found in the EC M: Collagen Fibers—At least 20 different types of collagen fibers are made in the body; Make up 20-25% of all protein in the body; Resemble entwined pieces of a steel cable; Very resistant to tension and pressure Elastic Fibers—Made of elastin protein surrounded by glycoproteins; May stretch to ½ times their resting length without breaking (distensibility) and then return to their original length (elasticity) Reticular Fibers—Type of collagen fiber that is thinner and shorter than regular collagen; Interweaves to form a scaffold that supports the cells and ground substance of tissues; Form “webs” in some organs to trap foreign cells Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.1 Extracellular Matrix (4 of 4) Figure 4.1 Extracellular matrix. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.1 Marfan Syndrome Marfan Syndrome results from defects in the gene that codes for the glycoprotein fibrillin-1 With defective fibrillin-1, elastic fibers cannot function properly because they are incorrectly anchored in the EC M Signs and symptoms include tall stature, long limbs and fingers, multiple skeletal abnormalities, joint dislocations, abnormalities of heart valves and lens of the eyes Most lethal complication is dilation of the largest artery in the body, the aorta, which may lead to aortic rupture and fatal blood loss if not treated immediately Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.1 Cell Junctions Cell Junctions—Connections of neighboring cells in a tissue linked to one another by integral proteins Tight (Occluding) Junctions—Junctions composed of integral “locking” proteins in adjacent plasma membranes; Prevents passage of macromolecules, although some are leaky and don’t provide a complete seal Desmosomes—Junctions composed of integral “linker” proteins in adjacent plasma membranes; Distribute mechanical stress Gap Junctions—Small pores made of protein channels in adjacent plasma membranes; Allow small substances to pass freely Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Let’s Talk Tissues: Epithelial Tissues Epithelial Tissue—Found on every external and internal body surface, so acts as a barrier between the body and the environment Functions of Epithelial Tissue:...—Continuous surface that shields underlying tissue from mechanical and thermal injury; Produce hard protein keratin; Undergoes mitosis rapidly and frequently...—Cells of the immune system are scattered throughout epithelial tissues...—Form glands that produce substances such as sweat, oil and hormones...—Selectively permeable barriers that allow certain substances to pass by passive or active transport....—Most epithelia are supplied with nerves that detect changes in the internal and external environments; Specialized epithelial cells are responsible for some sensations Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  4.2 Components and Classification of Epithelia (2 of 4) Components of Epithelia: Basement Membrane: anchors the Figure 4.3 Structure epithelial tissue to the underlying connective of epithelial tissue. tissue and has 2 components: Basal Lamina—This is the EC M of the epithelial tissue; Consists of collagen fibers and ground substance Reticular Lamina—Manufactured by the connective tissue deep to the epithelial tissue; Consists of reticular fibers and ground substance Epithelial cells have 1 side in contact with the extracellular space (... Surface), and 1 in contact with deeper cells or the basal lamina (... Surface) Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  4.2 Components and Classification of Epithelia (3 of 4) Classification of Epithelia: Number of Cell Layers – Simple Epithelia—Single layer of cells – Stratified Epithelia—More than one layer of cells – Pseudostratified Epithelia—Single layer of cells that appears to be multilayered Shape of the Cells – Squamous Cells—Flattened cells – Cuboidal Cells—Short cells – Columnar Cells—Tall and elongated cells Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (1 of 15) Simple Epithelia—One cell layer thick, Does not work for protection; Lines hollow organs and surfaces where diffusion or transport occurs; Includes: – Simple Squamous – Simple Cuboidal – Simple Columnar – Pseudostratified Columnar Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (2 of 15) Simple Squamous Epithelia—Single layer of flat cells; Resemble fried eggs that fit together like floor tiles; Diffusion occurs quickly across cells; Found in air sacs of lungs, serous membranes, and lining of blood vessels Figure 4.5a Structure of simple epithelia. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (3 of 15) Simple Cuboidal Epithelia—Single layer of roughly cube- shaped cells; Appear square with a large, central nucleus; Diffusion occurs and some secrete substances; Found in kidney tubules and glands Figure 4.5b Structure of simple epithelia. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  4.2 Covering and Lining Epithelia (4 of 15) Simple Columnar Epithelia—Single layer of tall cells; Appear rectangular in a section; Some have folds of the apical surface (microvilli); Some have cilia, which move something along the apical surface; Some produce secretions; Found in small intestine, uterine tube, kidney tubules and glands Figure 4.5c Structure of simple epithelia. Why is cilia helpful in the uterine tube? Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (5 of 15) Pseudostratified Columnar Epithelia—Single layer of cells that appears to be stratified; Looks this way because nuclei are at different heights and some cells are shorter; Most are ciliated; Include goblet cells that secrete mucus; Found in respiratory passages and nasal cavities for protection Figure 4.5d Structure of simple epithelia. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  4.2 Covering and Lining Epithelia (8 of 15) Stratified Epithelia—Thicker than simple epithelia; Effective protective barriers, so common in areas of high stress; Cell shape changes throughout the thickness of the tissue, so named according to the shape in their apical layers; Includes: – Stratified Squamous Epithelia (keratinized and nonkeratinized); Keratinized – Stratified Cuboidal Epithelia – Stratified Columnar Epithelia – Transitional Epithelia What is Keratin? atin is a protein that helps form hair, nails and your skin's outer layer (epidermis) Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (9 of 15) Stratified Squamous Epithelia—Nonkeratinized stratified squamous epithelia has distinct nucleated cells on the apical surface; Found in epithelium of mouth, pharynx, esophagus, anus, and vagina Figure 4.7a Structure of stratified epithelia. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (10 of 15) Stratified Cuboidal Epithelia—Rare in the human body; Two layers of cuboidal cells; Lines the ducts of sweat glands Figure 4.7b Structure of stratified epithelia. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (11 of 15) Stratified Columnar Epithelia—Rare in the human body; Few layers of cells that are columnar in apical layers and cuboidal in basal layers; Found in ducts of salivary glands; parts of male urethra, and the conjunctiva (membrane lining the surface of the eye) Figure 4.7c Structure of stratified epithelia. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (12 of 15) Transitional Epithelia—Cells in the basal layer are cuboidal and apical cells are dome-shaped when the tissue is relaxed; When stretched, apical cells appear squamous; Found in lining of kidneys, ureters, urinary bladder, and urethra Figure 4.7d Structure of stratified epithelia. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (14 of 15) Figure 4.8 Summary of epithelial tissues. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.2 Covering and Lining Epithelia (15 of 15) Figure 4.8 Summary of epithelial tissues. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Connective Tissues (1 of 2) Connective Tissue Functions:....—Bind tissue layers together in organs and anchor organs in place and to one another....—Certain connective tissues, such as bone and cartilage, support the weight of the body......—Bone protects internal organs; Cartilage and fat tissue provide shock absorption; Elements of the immune system are found within connective tissues....—Blood, which is the main transport medium in the body, is a type of connective tissue Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Connective Tissues (2 of 2) Classification of Connective Tissue: General Connective Tissue also known as Connective Tissue Proper— Widely distributed in the body, where it connects tissues and organs to one another and forms part of the internal architecture; Includes: – loose – dense – reticular – adipose tissues Specialized Connective Tissues—Class that includes – cartilage – bone – blood Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Cells that form Connective Tissue Proper (1 of 3) Fibroblasts—Produce protein fibers, ground substance, and other EC M elements; Usually lie close to collagen fibers that they produce Adipocytes—Fat cells with single large inclusion that contains lipids with organelles pushed to the perimeter Figure 4.12ab Cells of connective tissue proper. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Cells of Connective Tissue Proper (2 of 3) Mast Cells—Cells of the immune system with cytosolic inclusions (or granules) containing inflammatory mediators such as histamine Phagocytes—Immune cells that phagocytize foreign substances, microorganisms, and dead and damaged cells; Includes macrophages and neutrophils Other Immune Cells—Other cells of the immune system can move in and out of connective tissues depending on the needs of the body Figure 4.12cd Cells of connective tissue proper. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Types of Connective Tissue Proper (1 of 7) Loose (Areolar) Connective Tissue—Ground substance with all 3 types of protein fibers, fibroblasts, and other cells including immune cells; Jelly-like consistency; Found deep to the epithelium of the skin and in membranes; Supports and houses blood vessels Figure 4.13 Structure of loose connective tissue. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Types of Connective Tissue Proper (2 of 7) Dense Irregular Connective Tissue—Composed of protein fibers with mostly collagen fibers that are arranged haphazardly; Strong tissue that resists tension in all 3 planes; Found in dermis and around organs and joints Figure 4.14a Structure of dense connective tissue. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Types of Connective Tissue Proper (3 of 7) Dense Regular Collagenous Connective Tissue— Contains thick collagen fibers arranged in parallel bundles; Resist tension in one direction; Found in tendons (which join muscle to bone) and ligaments (which join bone to bone) Figure 4.14b Structure of dense connective tissue. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Types of Connective Tissue Proper (4 of 7) Dense Regular Elastic Connective Tissue—Also known as “elastic tissue;” Consists of mostly parallel elastic fibers with randomly oriented collagen fibers; Allow organs to stretch; Found in the lining of the large blood vessels and some ligaments Figure 4.14c Structure of dense connective tissue. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Types of Connective Tissue Proper (5 of 7) Reticular Tissue—Includes numerous reticular fibers(typically collagenous fibers) produced by surrounding fibroblasts; Form fine, meshlike networks for support and weblike nets that trap foreign cells; Forms part of basement membrane Figure 4.15 Structure of reticular tissue. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Types of Connective Tissue Proper (6 of 7) Adipose Tissue—Fat tissue consisting of adipocytes and surrounding fibroblasts and ECM; Adipocytes can increase in size; Functions in insulation, warmth, shock absorption, protection, and energy reserve Figure 4.16 Structure of adipose tissue. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Special Connective Tissues Cartilage Tough, flexible tissue that absorbs shock and is resistant to tension, compression, and shearing forces EC M is solid and gel-like with glycosaminoglycans, proteoglycans, collagen fibers, and elastic fibers Chondroblasts—Immature cartilage cells Chondrocytes—Mature cartilage cells, which live in small cavities called..... Surrounded by an outer sheath of dense irregular connective tissue called the....., which supplies blood to the cartilage Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Special Connective Tissues Bone Supports the body, protects vital organs, provides attachment sites for muscles, stores calcium salts, and houses bone marrow, which produces our red blood cells and stores fat Bone Cells – Osteo....—Carry out bone deposition – Osteo.....—Mature osteoblasts that are surrounded by EC M; Produce substances for bone maintenance – Osteo....—Multinucleated cells that carry out bone resorption (break down) Bone Remodeling—Bone deposition and bone resorption are constantly occurring in healthy bone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.3 Special Connective Tissues Blood EC M is fluid and is called Plasma, with water, dissolved solutes, and globular proteins Cells are..... (red blood cells), which carry oxygen,.... (white blood cells), which function in immunity, and cell fragments called....., which function in blood clotting Figure 4.19 Components of blood. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.4 Muscle Tissues Muscle Cells (Myocytes)—Excitable cells that respond to electrical or chemical stimulation; Cytoplasm is filled with bundles of proteins called Myofilaments; Surrounded by a small amount of EC M called Endomysium Striated Muscle Cells—Myofilaments are organized into regions that produce dark and light areas called “bands;” Alternating light-dark bands are called Striations Smooth Muscle Cells—Myofilaments are in irregular bundles scattered in the cytoplasm so no striations are visible Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.4 Types of Muscle Tissue (1 of 4) Skeletal Muscle—Found attached to the skeleton to produce body movement; Controlled by the nervous system; Typically voluntary movements; Formed by the fusion of embryonic myoblasts resulting in large, multinucleate cells (also called Muscle Fibers) Figure 4.21a Structure of muscle tissues. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.4 Types of Muscle Tissue (2 of 4) Cardiac Muscle—Found only in the heart; Involuntary contractions; Shorter than skeletal muscle cells with branches and a single nucleus; Intercalated discs, which contain gap junctions and tight junctions, are found between cells and permit heart muscle to contract as a unit Figure 4.21b Structure of muscle tissues. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.4 Types of Muscle Tissue (3 of 4) Smooth Muscle—Found in the walls of hollow organs, walls of blood vessels, the eyes, the skin, and the ducts of some glands; Involuntary contractions; Cells are flattened, with a single nucleus; Gap junctions in the plasma membrane connect cells to other smooth muscle cells Figure 4.21c Structure of muscle tissues. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.5 Nervous Tissue (1 of 2) Nervous Tissue—Makes up majority of the brain, spinal cord, and nerves; EC M is different from other tissues and contains few protein fibers but is mostly ground substance with unique proteoglycans Cells include Neurons and Neuroglial Cells Neuroglial Cells—Supportive cells that anchor neurons and blood vessels in place, speed up the rate of nerve impulse transmission, and circulate fluid around the brain and spinal cord Neuroglial cells can divide by mitosis Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.5 Nervous Tissue (2 of 2) Neurons—Generate, Figure 4.22 Structure of conduct, and receive nerve nervous tissue. impulses (electrical signals); Include 3 main parts: –...—Large center with the nucleus and organelles –...—Moves impulse to the target cell –....—Arms that receive messages – Neurons are amitotic Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.8 Tissue Repair (1 of 2) Tissue Repair—Process of wound healing; Occurs differently in different tissues and is dependent on the tissues ability to regenerate....—Damaged or dead cells are replaced with cells of the same type.....—Fibroblasts divide by mitosis and produce collagen to fill in the defect left by the injury; Results in Scar Tissue, which is dense irregular connective tissue Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  Conditions Favoring......: Conditions Leading to.....: Cell Type: Tissues with high regenerative Severe Injury: Extensive damage to capacity, such as epithelial tissues (skin, tissue structure and the ECM can gastrointestinal lining) and some make regeneration difficult, leading to connective tissues (liver, bone), are more fibrosis. likely to regenerate. Chronic Inflammation: Prolonged or Extent of Damage: Regeneration is more chronic inflammation can lead to likely when the damage is not extensive excessive deposition of collagen and and the tissue architecture is minimally other ECM components, resulting in disrupted. fibrosis. Presence of Stem Cells: Tissues with Lack of Regenerative abundant stem cells or progenitor cells can Capacity: Some tissues, such as regenerate effectively. For example, skin cardiac muscle or nervous tissue, have and liver tissues have significant limited regenerative capacity and are regenerative potential due to their stem cell more prone to fibrosis following injury. populations. Disruption of ECM: Significant Minimal Scarring: When the underlying damage to the ECM can interfere with extracellular matrix (ECM) is intact and not the ability of tissues to regenerate excessively damaged, regeneration can normally, favoring scar formation occur with less fibrosis. instead. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 4.8 Tissue Repair (2 of 2) Figure 4.26 Tissue repair by regeneration or fibrosis. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved Human Anatomy and Physiology Third Edition Chapter 05 The Integumentary System Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Skin Structure (1 of 3) The Integumentary System—Consists of the Skin and its accessory structures, including....,...., and..... The Skin (Cutaneous Membrane) —Largest organ in the body, making up 10-15% of our total body weight and has 2 main components Superficial Epidermis—Consists of keratinized stratified squamous epithelium resting on a basement membrane Deep Dermis—Consists of loose connective tissue and dense irregular connective tissue Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Skin Structure (2 of 3) The Skin (continued) Accessory structures include the......, and oil-producing..... Skin includes sensory neurons and receptors, and arrector pili muscles that attach to hair The epidermis is avascular, so the superficial layers consist of dead cells while the dermis is vascularized Below the dermis is the.... (Superficial Fascia or Subcutaneous Tissue) which is NOT part of the skin; Includes loose connective and adipose tissue and is highly vascularized Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Skin Structure (3 of 3) Figure 5.1 Basic anatomy of the skin. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Cellulite Cellulite—Term used to describe the dimpled, or “orange peel” appearance of the skin when the collagen bands form around adipose tissue in the hypodermis Tends to develop in thighs, hips, and gluteal area Influenced by genetics, sex, amount and distribution of adipose tissue, and age Considered to be a normal condition Diet and exercise minimize cellulite, but generally do not erase it altogether This is little evidence that products which claim to “cure” cellulite actually work Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Functions of the Integumentary System (1 of 5) Functions of the Integumentary System—Vital to maintaining homeostasis Protection Sensation Thermoregulation Excretion Synthesis of Vitamin D Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Functions of the Integumentary System (2 of 5) Protection—Protects underlying tissue from damage Mechanical Trauma—Such as stretching, pressure, or abrasion Pathogens—Disease-causing microorganisms Environment—Protects against environmental threats Skin absorbs ultraviolet (U V) radiation from the sun before it damages underlying tissues; Secretes lipid-based chemicals that repel water and salts which prevents water entering or leaving the body through the skin Sensation—Sensory receptors in the skin are perceived as sensations by the nervous system Detects potentially harmful stimuli which is crucial to homeostasis Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Functions of the Integumentary System (3 of 5) Thermoregulation—Maintenance of a stable internal body temperature through negative feedback loops Example 1: Body temperature rises above normal range – Stimulus—Body temperature increases – Receptor—Thermoreceptors in the brain detect the increased body temperature – Control Center—The heat-loss center in the hypothalamus of the brain receives the signal – Effector/Response—Neurons stimulate sweating and dilation of blood vessels in the skin to release heat – Return to Normal Range—Heat-loss center stops the response when body temperature returns to normal Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Functions of the Integumentary System (4 of 5) Figure 5.2 Maintaining homeostasis: The integumentary negative feedback loop activated in response to rising body temperature Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.1 Functions of the Integumentary System (5 of 5) Excretion—Small amounts of metabolic waste products, including lactic acid and urea, are eliminated in sweat Small but significant contribution Vitamin D (Calcitriol) Synthesis—Required for calcium absorption, which is needed for nerve and muscle function, bone building and maintenance, and other processes Precursor compound of Vitamin D is in the deep cells of the epidermis When exposed to U V radiation, this compound is converted to Cholecalciferol, which enters the bloodstream Modified by the liver, then kidneys to form Calcitriol Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.2 The Epidermis Epidermis—Superficial part of the skin; Composed of several cells types and up to 5 layers or Strata.....—Make up approximately 95% of cells in the epidermis; Provide strength to the epidermis Manufacture Keratin, which is a fibrous protein that makes tissue strong and resistant to mechanical stress, aids in waterproofing, immune response, barrier formation. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.2 Topical Medications The lipid-based substance that coats the epidermis is useful therapeutically Some medications are toxic if swallowed, but are safe when applied to the skin if they are polar compounds that cannot pass through the epidermis to reach blood vessels (ex. Hydrocortisone Cream or antibiotic ointments) However, hydrophobic or nonpolar substances cross the epidermis and provide a convenient route of administration for certain medications (such as hormones in birth control patches retinoid creams) Unfortunately, many poisons and toxins are also nonpolar and may cross the epidermis Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.2 Other Cells of the Epidermis Other Cells of the Epidermis Dendritic (Langerhans) Cells— Phagocytes of the immune system that protect the skin and deeper tissues Tactile (Merkel) Cells— Sensory receptors that detect light touch and differentiate shapes and textures; Numerous in fingertips, lips, and the base of hairs Melanocytes— Produce...., which is an orange-red to brown-black pigment (discussed in Module 5.4) Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.2 Thick and Thin Skin (1 of 2) Thick and Thin Skin (only refers to epidermis) Thick Skin—Found on locations subject to more mechanical stress, including the palms of the hands, palmar surfaces of fingers, soles of the feet, and plantar surfaces of toes – Contains all 5 strata and a very thick stratum corneum – Lacks hair follicles, but has numerous sweat glands Thin Skin—Found on remainder of body – No stratum lucidum and thinner stratum corneum – Includes hair follicles, sweat and sebaceous glands Callus—Additional layers of stratum corneum; Forms in response to repeated pressure Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.2 Thick and Thin Skin (2 of 2) Figure 5.5 Thick and thin skin Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.3 The Dermis (1 of 4) The Dermis—Deep part of the skin; Houses the blood supply of the epidermis; Contains sensory receptors; Anchors the epidermis in place; Divided into 2 layers Papillary Layer—Superficial layer of the dermis Makes up about 20% of the depth of the dermis Made of loose connective tissue At the dermis-epidermis junction, special collagen fibers extend into the basement membrane to anchor the epidermis; Repetitive trauma disrupts these fibers and causes a fluid-filled pocket called a blister The surface of the papillary layer folds into projections that push into the epidermis called Dermal Papillae Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.3 The Dermis (2 of 4) Dermal Papillae: – Provide blood supply to the epidermis – House Tactile (Meissner) Corpuscles, which respond to light touch, and distinguish shape and texture of objects; Numerous in fingertips, lips, face, and external genitalia Reticular Layer—Deep layer of the dermis Made of dense irregular connective tissue, which strengthens the dermis and allows it to stretch, and house Blood vessels, sweat glands, hairs, sebaceous glands, and sensory receptors. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.3 Skin Markings Skin Markings—Interactions between the epidermis and dermis are visible as small lines in the epidermis Most obvious are on the thick skin; Dermal papillae are prominent and arrange into Dermal Ridges The epidermis then indents to produce...... that occur in patterns unique to each individual; Sweat pores open along these ridges and leave a...... on surfaces Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.3 Skin Markings Figure 5.8 Importance of Skin Markings (continued) tension lines for surgical Gaps between collagen incisions bundles in the reticular layer form Tension, or.... Lines Run in a circular pattern in the neck and trunk and longitudinally in the head and limbs.... are deep creases found on areas such as the palms Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.3 Skin Wrinkles (1 of 2) Wrinkles—Result from age-related decreases in collagen and elastic fibers, proteoglycans, and adipose tissue in the dermis Exposure to U V radiation and cigarette smoking accelerate formation of wrinkles The appearance of wrinkles can be diminished by: Botox ® contains a bacterial toxin that paralyzes facial muscles for 4-6 months, causing the overlying skin to appear smoother Fillers containing adipose tissue, collagen, and/or proteoglycans are injected into wrinkles to temporarily “fill” them Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.3 Skin Wrinkles (2 of 2) The appearance of wrinkle can be diminished by: (continued) Peels use lasers, chemicals, or abrasion to remove the epidermis and superficial dermis to cause formation of new, hopefully firmer, skin Topical creams contain ingredients that claim to reduce the appearance of wrinkles; however, most creams, particularly nonprescription products, have little effect on wrinkles Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  5.4 Melanin (1 of 4) Melanin—Produced in vesicles called Melanosomes, in melanocytes The enzyme Tyrosinase joins 2 molecules of the amino acid tyrosine to form melanin Melanosomes migrate to the tips of the melanocyte and are taken into the keratinocyte by phagocytosis Melanin is transported to the area superficial to the nucleus, where it shields the DN A from U V radiation, although it is not complete protection – Melanin degrades after a few days, so it must be replaced Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.4 Melanin (3 of 4) Melanin (continued) Melanin synthesis increases on exposure to U V radiation – Immediate Effects—Oxidize the melanin, which darken – Secondary Effects—Damage DN A of melanocytes, which increases melanin production Melanin also decreases the synthesis of vitamin D to control the amount and keep it within a specific range – Individuals living in Africa have darker skin to prevent excess vitamin D production, while people in northern Europe have lighter skin to synthesize more vitamin D Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.4 Melanin (4 of 4) Melanin (continued) Common variations of pigmentation: – Freckle—Small area of increased melanin production in a local spot – Mole (Nevus) —Area of increased pigmentation, caused by local proliferation of melanocytes – Albinism—Melanocytes fail to manufacture tyrosinase; Results in lack of skin pigmentation and greatly increased the risk of keratinocyte DN A damage from U V radiation Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.3 Pseudoscience Exposed: Tanning and a “Healthy Tan” Tanning is a $5-billion-a-year business in United States alone where salons promote the notion of a “healthy tan” But is there such a thing as a healthy tan? While UV A rays are linked with tanning and UV B rays are linked with burning, the mechanism of increased melanin production is the same for both types of rays—oxidative damage to existing melanin and DN A damage to melanocytes that can lead to skin cancer Any amount of tanning damages melanocytes and other skin elements, ages skin prematurely, and increases risk of skin cancer Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Accessory Structures of the Integument: Hair, Nails, and Glands Accessory Structures or Appendages of the Integument All are derived primarily from the epithelium Each structure assists the integument in performing overall functions Includes: – Hair – Nails – Sweat Glands – Sebaceous Glands Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Hair Hair or Pili—Small, filamentous structures that project from all surfaces of the skin except the regions with thick skin, the lips, and parts of the genitalia Consists of squamous keratinized epithelial cells Function in protection – For example, hair around the eyes and in the nose keep out foreign objects and hair on the head protects against U V radiation Function in sensation – Sensory neurons associated with hair detect environmental changes Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Hair Hair Structure—Hair is composed of the following parts: Hair Shaft—Projects from the skin’s surface – Columns of dead keratinized epithelial cells – Each strand has 3 regions ▪......—Present in thick hairs only; Includes soft keratin in the core, similar to that in the epidermis ▪.....—Several layers of keratinocytes with hard keratin ▪......—Single layer of keratinocytes with hard keratin; Wears over time producing “split ends” Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Hair Hair Structure (continued).....—Portion embedded in the dermis – Arrector Pili Muscles attach to the dermal root sheath and contract causing Piloerection, which causes “goosebumps” Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Hair Hair Structure (continued) Hair Root (continued) – Hair Bulb—Enlarged area at the base of the root with a projection called the Hair Papilla, which supplies capillaries to the root Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Hair Hair Growth—Hair grows at different rates for different individuals, but averages about 1-1.5 cm per month Growth Stage Resting Stage Growth and resting stages vary among individuals and hair types and determine maximal hair length Alopecia—Baldness caused by the death of hair follicles Male and Female Pattern Baldness—Baldness caused by hormones, particularly testosterone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Hair Hair Pigment and Texture Lanugo—Nonpigmented hair that covers the body in a fetus; Falls out after birth... Hair—Thick, coarser, and pigmented hair found on the scalp and around the eyes... (peach fuzz)—Thin, nonpigmented hair found on the rest of the body; After puberty, much of the vellus hair is replaced by terminal hair but the amount differs by sex: – In males, about 90% of the vellus hair is replaced – In females, about 35% of the vellus hair is replaced Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Hair Hair Pigment and Texture (continued) Hair Color—Determined primarily by the amount of melanin produced by melanocytes – Blonde hair melanocytes produce... melanin – Black hair melanocytes produce.... melanin Red Hair has a special reddish pigment that contains..... Age—Melanocytes in hair produce less melanin as we age, turning the hair gray or white Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Nails Nails—Hard structures located at the end of digits; Safeguard fingertips and act as tools Consist of stratified squamous epithelium and hard keratin Nail Plate—Portion of the nail that sits on top of the epidermal Nail Bed and divides into: – Nail Body—Visible portion of the nail plate – Nail Root—Portion of the nail plate under the skin with the Nail Matrix with actively dividing cells Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Nails Nail Growth—Growth is continuous with fingernails growing about 0.5 mm per week, while toenails grow more slowly Keratinocytes die as they move away from the matrix Nail Pigment—Nails contain no melanocytes, so they are translucent with an opaque half-moon shaped region near the proximal nail fold called the Lunula, which has accumulated more keratin Nail beds are pinkish is a well-oxygenated individual and bluish (cyanotic) in a poorly-oxygenated individual Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Glands (1 of 5) Sweat (Sudoriferous) Glands—All 4 types of sweat glands release their various products by exocytosis, a type of secretion called Merocrine Secretion Eccrine Sweat Glands—Most prevalent sweat gland – Sweat exits through a duct with a sweat pore in the epidermis – Eccrine sweat is 99% water with small amounts of electrolytes and waste products – Primary function is..... Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Glands (2 of 5) Sweat (Sudoriferous) Glands (continued) Apocrine Sweat Glands—Large glands in the dermis, but found only in the axillae (armpits), anal area, and areolae (darkened area around the nipples) – Sweat exits onto a hair follicle rather than through a pore – Apocrine sweat is thick and rich in proteins – When secreted, the sweat is odorless, but when metabolized by bacteria, it produces odor – Secretion begins at puberty with influence from...... Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Glands (3 of 5) Sweat (Sudoriferous) Glands (continued) Ceruminous Glands—Modified apocrine glands that secrete thick Cerumen (.....) – Secreted onto hair follicles to protect and lubricate the tympanic membrane, or eardrum, of the ear Mammary Glands—Highly specialized sweat glands that produce a modified sweat called..... – Milk contains proteins, lipids, sugars, and other substances to nourish a newborn infant Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Glands (4 of 5) Sebaceous Glands—Branched glands with clusters of secretory cells call Acini that surround small ducts that usually empty onto a hair follicle Numerous in face and scalp Produce Sebum, a waxy, oily lipid mixture Secretion increases at puberty with influence from sex hormones, particularly testosterone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.5 Acne Acne Vulgaris or Acne—As many as 96% of teenagers and young adults experience some degree of acne Caused by an accumulation of sebum and dead cells within the sebaceous glands producing a Comedone, or Blackhead If these become infected with the bacterium Propionibacterium acnes, inflammation and formation of a Pustule, or Pimple may occur and may lead to scars Male sex hormones contribute strongly to the development of acne and is more pronounced in males entering puberty Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.6 Wounds Wound—Common skin pathology defined as any disruption in the skin’s integrity Wounds may involve the epidermis, the dermis, and occasionally deeper tissues Includes: – Lacerations—A cut or tear in the skin; Typically repaired with sutures, or stitches – Burns – Cancers Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.6 Burns Burns—Skin wound caused by agents such as heat, extreme cold, electricity, chemicals, and radiation Grouped based on extent and depth of tissue damage......—Superficial burns – Only epidermis is damaged – Erythema and minor pain are present but no blisters or permanent damage occur – No treatment is usually required......— Partial thickness burns Epidermis and part of the dermis are damaged Significant pain, blistering, and possibly scarring occur Treatment is usually required Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.6 Burns Burns (continued).....—Full thickness burns – Epidermis, dermis, hypodermis, and possibly deeper tissues are damaged – Not painful initially because of nerve damage, but major tissue damage and significant scarring occur – Problems with dehydration due to massive fluid loss and infection are serious complications – Treatment may require extensive skin grafting, which involves transplanting skin from another part of the body onto the wound Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.6 Burns Figure 5.13 The three classes of burns Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.6 Burns Burns (continued) Second and third-degree burns can be described by estimating the percentage of body surface they affect using the.... – Divides the body into 11 areas, each representing 9% of the total body surface area (genital area is 1%) – For example, a burn involving the entire right lower limb covers 18% of the body – Used to estimate how much fluid to give burn patients – Must be modified if body proportions are different (i.e. infants or obese individuals) Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.6 Burns Figure 5.14 Rule of nines: Estimating the extent of a burn Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 5.6 Skin Cancer Cancer—One of the most common diseases in the world that claims millions of lives each year Mutations in a cell’s DN A induce the cell to lose control over the cell cycle resulting in a Tumor, or cluster of undifferentiated cells Cancerous tumors prevent the tissue from functioning normally, and can Metastasize, or spread to other tissues Skin Cancer—Linked to exposure to U V radiation, and other cancer causing agents, called Carcinogens Three common skin cancers include: Basal Cell Carcinoma, Squamous Cell Carcinoma, and Malignant Melanoma Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved Human Anatomy and Physiology BIOL3306 Fall 2024 Week 2: Bones & Bone Tissue Professor: Nour Nissan Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved The Skeletal System The Skeletal System—Includes the bones, joints, and other supporting tissues Bones—Main organs of the system; Adults typically have............. bones – Each bone includes: ▪ Bone (Osseous) Tissue ▪ Dense regular collagenous tissue ▪ Dense irregular connective tissue ▪ A tissue called Bone Marrow Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Functions of the Skeletal System Functions of the Skeletal System.......................—Bones such as the skull, sternum, and ribs protect underlying organs............................................................—Bone stores minerals including calcium, phosphorus, and magnesium salts; These minerals are electrolytes, acids, and bases in the blood, and are critical for electrolyte and acid-base maintenance......................................—Red Bone Marrow in bones is the site of............................., or formation of blood cells........................—Yellow Bone Marrow in bones contains adipocytes with stored triglycerides.......................—Bones are the sites of attachment for most skeletal muscles; When muscles contract, they pull the bones which generates movement around a joint.......................—The skeleton supports the weight of the body and provides its structural framework Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Functions of the Skeletal System Figure 6.1 Functions of the skeletal system. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Bone Structure (1 of 6) Classification of Bone by Shape Long Bones—Longer than wide; Examples include bones of the limbs; Some long bones are very small Short Bones—About as long as wide or roughly cube- shaped; Examples include the wrist and ankle bones Flat Bones—Thin and broad; Examples include most of the skull bones and bones of the pelvis Irregular Bones—Irregular shapes; Examples include the vertebrae Sesamoid Bones—Small, flat, oval-shaped bones located within tendons; An example is the kneecap Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Bone Structure (2 of 6) Figure 6.2 Classification of bones by shape. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  6.1 Bone Structure (3 of 6) Structure of a Long Bone Periosteum—Outer dense irregular connective tissue membrane with blood vessels and nerves Perforating Fibers—Collagen anchors that penetrate into bone matrix to attach the periosteum Diaphysis—Shaft of the bone with a....................................... lined by the Endosteum (A membrane lining the inner surface of the bony wall) and filled with marrow Epiphyses—Ends of a long bone (filled with Red Marrow) covered with Articular Cartilage, which is composed of hyaline cartilage Compact Bone—Hard, dense outer bone that resists linear compression and twisting forces Spongy (Cancellous) Bone—Inner, honeycomb- like bone framework that resists forces in many directions and provides a place for bone marrow to reside Epiphyseal Lines—Remnants of an Epiphyseal (Growth) Plate, which is a line of hyaline cartilage actively growing in children and adolescents Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Bone Structure (4 of 6) Structure of Short, Flat, Irregular, and Sesamoid Bones Share similarities with long bones, but have fewer structures In flat bones, the spongy bone is called Diploe, and in some flat and irregular bones of the skull, there are air-filled spaces called sinuses to make the bones lighter Figure 6.4 Structure of short, flat, irregular, and sesamoid bones. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Bone Structure (5 of 6) Blood and Nerve Supply to Bone Bones are well supplied with blood vessels and many sensory fibers – Blood supply to long bones is from the periosteum and 1 or 2 Nutrient Arteries that enter through a small hole in the diaphysis called the............................... to supply the internal structures of the long bone – Blood supply to short, flat, irregular, and sesamoid bones is provided mostly by vessels in periosteum that penetrate bone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Bone Structure (6 of 6) Red and Yellow Marrow Yellow Bone Marrow—Consists mostly of blood vessels and adipocytes. (Can make.................,................., or during life threatening emergencies can turn to red bone marrow to produce blood cells) Red Bone Marrow—Network of reticular fibers supporting islands of hematopoietic cells (where.................. ,.......................... and......................... form) – Infants and young children have mostly red bone marrow because of their rapid growth rate, which begins to change to yellow marrow at about age 5-7 – Adults have mostly yellow marrow with red marrow found mostly in flat bones such as the hip bone, sternum, skull, vertebrae, ribs, shoulder blades and ends of long bones. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.1 Bone Marrow Transplantation Leukemia, sickle-cell anemia, and aplastic anemic patients have improperly functioning hematopoietic cells and may benefit from Bone Marrow Transplantation A needle is inserted into the pelvic bone of a matching donor, called a Bone Marrow Harvest, and up to 2 quarts of red marrow is withdrawn Recipient’s marrow is destroyed with chemotherapy and/or radiation and donor marrow is given intravenously so that cells can travel to the recipient’s marrow cavities If successful, new blood cells will be produced in 2–4 weeks, but infection and transplant rejection are possible Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 The Extracellular Matrix of Bone (1 of 3) The Extracellular Matrix of Bone (Bone Matrix) Inorganic Matrix—About 65% of bones total weight Consists mostly of calcium salts and phosphorus as part of a large mineral called..................................... [Ca10 (PO4 )6 (OH)2 ] which gives bone its hardness and ability to resist compression and bending Bicarbonate (HCO3  ), potassium, magnesium, and sodium salts are also in the inorganic matrix Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 The Extracellular Matrix of Bone (2 of 3) The Extracellular Matrix of Bone (continued) Organic Matrix (Osteiod)—About 35% of bones total weight – Consists of protein fibers (mostly collagen), proteoglycans, glycosaminoglycans, glycoproteins, and bone-specific proteins such as Osteocalcin – Collagen helps bone resist torsion (twisting) and tensile (pulling or stretching) forces that would cause breaks in bones, and aligns with hydroxyapatite crystals to enhance bone hardness Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 The Extracellular Matrix of Bone (3 of 3) Figure 6.5 The importance of bone matrices. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 Bone Cells Bone is dynamic tissue Figure 6.6 Types of bone cells. because new bone is continually being formed as older bone is broken down Osteoblasts build bone and matures into; Osteocytes which maintain bone Osteoclasts break down bone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 Osteopetrosis Osteopetrosis or “Marble Bone Disease” occurs when defective osteoclasts do not properly degrade bone Bone mass increases, but the bone is weak and brittle and appears stonelike (petra = “rock”) Infantile Osteopetrosis—Predominantly inherited, more severe form; Skull openings fail to enlarge trapping nerves resulting in blindness and deafness; Medullary cavities in all bones fail to enlarge, decreases red bone marrow which can prove fatal; Drugs are used to stimulate osteoclasts and bone marrow Adult Osteopetrosis— Inherited; Symptoms include bone pain, recurrent fractures, nerve trapping, and joint pain Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 Histology of Bone (1 of 3) Histology of Bone Compact Bone—Hard, dense, outer shell that is able to resist a great amount of stress that would typically strain or deform an object – Units are called.................... or Haversion Systems Spongy Bone—Resists forces from many directions and forms a protective framework for the bone marrow although not weight bearing – Organized into branching “ribs” of bone called....................... ▪ Trabeculae—Covered with endosteum; Contain concentric lamellae, houses osteocytes; Access blood supply from blood vessels in bone marrow Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 Histology of Bone (2 of 3) Compact Bone Osteon Structure – Lamellae (Concentric Lamellae) —Rings of very thin layers of bone; Osteons contain 4 to 20 lamellae; Collagen fibers of adjacent lamellae run in opposite directions which resists twisting and bending forces – Central (Haversian) Canal—Contains blood vessels and nerves; Lined by endosteum – Lacunae—Small cavities between lamellae filled with E C F; About 20,000–30,000 osteocytes and lacunae are found in each cubic millimeter of bone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.2 Histology of Bone (3 of 3) Figure 6.9 Structure of compact bone. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.3 Osteoporosis and Healthy Bone Tissue (1 of 2) Osteoporosis—Bone disease caused by inadequate inorganic matrix in the EC M Makes bone brittle and increases the risk of fractures, which also heal more slowly Note the differences in healthy versus osteoporotic bone (right) Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.3 Osteoporosis and Healthy Bone Tissue (2 of 2) Causes of Osteoporosis—Dietary factors, such as calcium ion and vitamin D deficiency; Female sex; Advanced age; Lack of exercise; Hormonal factors, such as lack of protective estrogen in postmenopausal women; Genetic factors; Diseases of the skin, digestive and urinary systems Preventative Measures and Treatments—Ensure adequate intake of calcium and vitamin D; Engage in weight-bearing exercises; Replace estrogen, if appropriate; Use drugs that inhibit osteoclasts or stimulate osteoblasts Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  6.4 Bone Growth in Length (1 of 5) Longitudinal Growth—Lengthening of long bones when chondrocytes divide at the Epiphyseal Plate The Epiphyseal Plate has 5 Different Zones of Cells: 1) Zone of Reserve Cartilage—Cells are not directly involved in bone growth, but can divide if needed 2) Zone of Proliferation—Chondrocytes are...............................................;........................................................ 3) Zone of Hypertrophy and Maturation—Contains................................. 4) Zone of Calcification—Contains..............................., matrix becomes calcified; Far from blood supply 5) Zone of Ossification—Contains calcified chondrocytes and osteoblasts to build bone Zones 2–5 are actively involved in longitudinal growth, and as cells divide, the cells “above” them progressively become part of the next zones Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  6.4 Bone Growth in Length (2 of 5) Figure 6.13 Structure of the epiphyseal plate. Bone growth Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.4 Bone Growth in Length (3 of 5) Steps of Longitudinal Growth 1) Chondrocytes divide in the zone of proliferation 2) Chondrocytes that reach the next zone enlarge and mature Lacunae surrounding the chondrocytes are larger here 3) Chondrocytes die and their matrix calcifies 4) Calcified cartilage is replaced with bone In the zone of ossification, osteoblasts invade the calcified cartilage and lay down bone; Osteoclasts resorb the calcified cartilage/bone which is replaced by bone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.4 Bone Growth in Length (4 of 5) Figure 6.14 Growth at the epiphyseal plate. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.4 Bone Growth in Length (5 of 5) Longitudinal growth continues at the epiphyseal plate as long as mitosis is happening in the zone of proliferation At about 12–15 years of age, the rate of mitosis slows, but ossification in steps 3 and 4 continues which causes the epiphyseal plate to shrink until the zone of proliferation is overtaken by the zones of calcification and ossification When the zone of proliferation completely ossifies (between ages 13 up to 21), the plate is said to be “closed” and leaves a remnant called the....................................... Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.4 Bone Growth in Width Appositional Growth—Growth of all bones in width; May continue after bone growth in length ceases Osteoblasts between the periosteum and the bone surface lay down new bone Begins with the formation of new circumferential lamellae; As new lamellae are added, the deeper circumferential lamellae are removed or incorporated into osteons Primarily thickens the compact bone of the diaphysis; Osteoclasts in the medullary cavity digest the inner circumferential lamellae so as bones increase in width, their medullary cavities enlarge as well Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.4 Gigantism and Acromegaly Gigantism—Excess growth hormone is secreted in childhood before the closure of the epiphyseal plates Excessive longitudinal and appositional growth occurs Acromegaly—Excess growth hormone is secreted after closure of the epiphyseal plates Results in enlarged bones of the skull, face, hands and feet, and soft tissues such as the tongue Can cause heart and kidney malfunction and diabetes mellitus Both gigantism and acromegaly are generally treated by removing a tumor that secretes growth hormone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Remodeling (1 of 5) Bone Remodeling—The continual process of bone formation, by Bone Deposition, and bone loss, by Bone Resorption Occurs for many reasons: – Maintenance of calcium ion homeostasis – Bone repair – Replacement of primary bone with secondary bone – Replacement of older, brittle bone, with newer bone – Bone adaptation to tension and stresses Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Remodeling (2 of 5) Bone Remodeling (continued) In healthy adult bone, bone formation and bone loss occur simultaneously by osteoblasts and osteoclasts, respectively In children, bone formation outweighs bone loss Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Remodeling (3 of 5) Bone Remodeling in Response to Tension and Stress The heavier the load a bone carries, the more bone tissue is deposited in that bone – Tension—Stretching force; Stimulates bone............... – Pressure—Application of a continuous downward force; Stimulates bone.................. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Remodeling (4 of 5) Other Factors Influencing Bone Remodeling Hormones – Testosterone strongly promotes bone deposition, while estrogen depresses osteoclast activity Age – Hormone levels decline with advancing age, such as growth hormone, which causes a reduction in protein synthesis, and estrogen, which reduces the protective effects of the hormone on bone remodeling Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Remodeling (5 of 5) Other Factors Influencing Bone Remodeling (continued) Nutrient Intake – Calcium Ion Intake—Required for bone deposition – Vitamin D Intake—Promotes calcium ion absorption in the intestines and prevents calcium loss in the urine; Inadequate amounts in children causes Rickets, which results in bone deformities, fractures, and muscle weakness – Vitamin K Intake—Required for osteocalcin to bind to calcium ions; Promotes proliferation of osteoblasts, increases their lifespan, and causes them to deposit more matrix; Inhibits osteoclast division and activity Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Calcium Ion Intake and Fracture Risk National Academy of Sciences—Recommends a very high amount— 1,000 mg/day for adults ages 19–50 and 1,200 mg/day for adults over age 50 However, long-term studies have shown that high calcium ion intakes do not result in lower fracture rates in the U.S., and that lower calcium ion intakes in some other countries does not correlate with high fracture rates Also, high calcium ion intakes have been linked to prostate cancer in men Most data suggest that 700 mg/day with adequate vitamin D and K intakes are appropriate for most people Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Repair (1 of 5) Bone Repair: Steps of Fracture Healing 1) A hematoma fills the gap between the bone fragments Hematoma—Ruptured blood vessels that bleed into the injured site. 2) Fibroblasts and chrondroblasts infiltrate the hematoma, and a............................ forms Fibroblasts form dense irregular connective tissue and chondroblasts secrete hyaline cartilage; These 2 components produce the soft callus Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Repair (2 of 5) Figure 6.17 The process of fracture repair. 1 A hematoma fills the gap between the bone fragments. 2 Fibroblasts and chondroblasts infiltrate the hematoma, and a soft callus forms. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Repair (3 of 5) Bone Repair: Steps of Fracture Healing (continued) 3) Osteoblasts build a................................ Over several weeks, osteoblasts from the periosteum lay down a collar of primary bone called a bone callus 4) The bone callus is remodeled and primary bone is replaced with secondary bone Over several months, the primary bone is resorbed and replaced with secondary bone; The bone callus often remains visible following full healing of the injury Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Repair (4 of 5) Figure 6.17 The process of fracture repair. 3 Osteoblasts build a bone callus. 4 The bone callus is remodeled and primary bone is replaced with secondary bone. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 6.5 Bone Repair (5 of 5) Classes of Fractures Simple (Closed) Fractures—Skin and surrounding tissue remain intact Compound (Open) Fractures—Damage around the fracture Treatment of Fractures—Stabilization of the fracture, followed by immobilization for about 6 weeks Closed Reduction—Bone ends are brought into contact Open Reduction—Fracture is surgically fixated with plates, wires, and/or screws Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved Human Anatomy and Physiology BIOL3306 Fall 2024 Week 2: The Skeletal System Professor: Nour Nissan Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.1 Structure of the Skeleton and Skeletal Cartilages (1 of 4) The Skeleton—Includes approximately........... bones and associated skeletal cartilages Skull—The skeleton’s most complex structure with 22 bones;............. cranial bones encase the brain;.............. facial bones form the framework for the face Vertebral Column—Includes....... vertebrae; The top....... vertebrae encase the spinal cord; The inferior bones, the sacrum and coccyx, are made of fused vertebrae Thoracic (Rib) Cage—Includes......... pairs of ribs, the sternum, part of the vertebral column; Protect the structures in the thoracic cavity Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.1 Structure of the Skeleton and Skeletal Cartilages (2 of 4) The Skeleton (continued) Pectoral Girdle—Includes the clavicle and scapula; Supports the upper limb and anchors it to the trunk Upper Limb—The arm includes the humerus; The forearm includes the radius and ulna; The wrist includes the carpals; The hand and fingers include the metacarpals and phalanges Pelvic Girdle—Includes pelvic bones and the sacrum; Each pelvic bone is composed of an ilium, ischium, and pubis; Supports the lower limb and anchors it to the trunk Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.1 Structure of the Skeleton and Skeletal Cartilages (3 of 4) The Skeleton (continued) Lower Limb—The thigh includes the femur; The leg includes the tibia and fibula; The ankle includes the tarsals; The foot includes the metatarsals and phalanges Structural Divisions of the Skeleton Axial Skeleton—Longitudinal axis of the body; Structured for protection –...............,........................,................... Appendicular Skeleton—Structured for motion –............................................. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.1 Structure of the Skeleton and Skeletal Cartilages (4 of 4) Figure 7.1 Divisions of the skeletal system. The axial skeleton is shaded orange; the appendicular skeleton is shaded tan. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (1 of 18) Skull Bones—All skull bones are united in adults by immoveable joints called Sutures, except the mandible (lower jaw bone) Cranial Bones (Cranium) (.....) Single Bones—Frontal, Occipital, Ethmoid, Sphenoid Paired Bones—Temporal, Parietal Facial Bones (......) Single Bones—Mandible, Vomer Paired Bones—Maxilla, Zygomatic, Nasal, Lacrimal, Palatine, Inferior Nasal Concha Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (2 of 18) Figure 7.2 Basic structure of the skull: anterolateral view of the cranial and facial bones. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (5 of 18) Table 7.2 Cranial Bones Frontal-Occipital Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (6 of 18) Table 7.2 Cranial Bones Temporal Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (7 of 18) Table 7.2 Cranial Bones Sphenoid-Ethmoid Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (8 of 18) Table 7.2 Facial Bones Nasal-Mandible Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (9 of 18) Table 7.2 Facial Bones Maxillae-Vomer Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (10 of 18) Figure 7.5 Anterior view of the skull. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (11 of 18) Figure 7.5 Anterior view of the skull. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (12 of 18) Figure 7.6 Lateral view of the skull. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (13 of 18) Figure 7.6 Lateral view of the skull. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Overview of Skull Structure (18 of 18) Figure 7.9 Internal view of the skull. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Concept Boost: Understanding How Skull Bones Relate to One Another To see individual skull Figure 7.10 Disarticulated skull. bones and how they fit together, look at the disarticulated or “exploded” skull to the right Think of the skull as a 3-dimensional jigsaw puzzle Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Cavities of the Skull (1 of 6)................—Houses the Figure 7.11 The orbit. eyeball, its associated blood vessels, muscles, and nerves, and the lacrimal gland, which produces tears Formed by 7 bones: Frontal, Maxilla, Zygomatic, Sphenoid, Ethmoid, Lacrimal, Palatine Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Cavities of the Skull (5 of 6) Paranasal Sinuses—Found Figure 7.13 Paranasal sinuses within the frontal, sphenoid, ethmoid, and maxillary bones Lined with mucous membranes and connect to the nasal cavity Lighten the skull and enhance voice resonance Infections result in sinusitis Oral Cavity—Houses the teeth, the tongue, and some salivary glands; First part of the gastrointestinal tract of the digestive system Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.2 Hyoid Bone Figure 7.15 Structure of the hyoid bone. Hyoid Bone—Small, C- shaped bone suspended in the superior neck by muscles and ligaments Attachment point for muscles involved in swallowing and speech Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Overview of the Vertebral Column (1 of 5) Vertebral Column (Spine) —Average of 33 Vertebrae 7 Cervical— (C1  C7 ) located in the neck 12 Thoracic— (T1  T12 ) articulate with the ribs 5 Lumbar— (L1 –L5 ) located in the lower back 5 fused Sacral (Sacrum)—Articulate with the pelvic bones 3–5 fused Coccygeal (Coccyx)—Located at the most inferior end of the vertebral column Spinal Curvatures Primary (Thoracic and Sacral)—Present during fetal period Secondary (Cervical and Lumbar) —Develop after fetal period Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Overview of the Vertebral Column (2 of 5) Spinal Curvatures (continued) Figure 7.16 The vertebral Cervical Curvature column and normal spinal curvatures. – Concave; (C2  T2 ) Thoracic Curvature – Convex; (T2  T12 ) Lumbar Curvature – Concave; (T12  L5 ) Sacral Curvature – Convex; Lumbosacral junction-Coccyx Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Overview of the Vertebral Column (3 of 5) Thoracic Vertebrae—Larger than................................... Lumbar Vertebrae—............................... Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Overview of the Vertebral Column (4 of 5) Abnormal Spinal Curvatures Scoliosis—Lateral curvatures that appear C or S shaped; May be congenital (deformities present at birth), neuromuscular (resulting from trauma to the nerves and muscles), or idiopathic (unknown cause) – Mild cases may cause no symptoms and require no treatment; Severe cases may require back braces, physical therapy, or surgery Abnormal Spinal Curvatures (continued) Kyphosis—Gives a “humpback” appearance; Exaggerated thoracic curvature; Caused by arthritis, osteoporosis, vertebral fractures, and developmental abnormalities – Mild cases generally require no treatment; Severe cases can be debilitating, causing heart and lung dysfunction, nerve compression, and significant pain, and usually require surgery Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Overview of the Vertebral Column (5 of 5) Figure 7.17 examples of abnormal spinal curvatures. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Structure of the Vertebrae (12 of 18) Table 7.3 Comparison of Cervical, Thoracic, and Lumbar Vertebrae Characteristic Cervical Vertebrae Thoracic Vertebrae Lumbar Vertebrae Body shape Small and oval; a body; Larger and heart- Largest and kidney- and size the dens on the superior shaped; contain costal shaped surface of facets its body Vertebral Triangular Circular Flattened triangular foramen shape Transverse Contain transverse Long; contain articular Short with no facets or processes foramina facets for ribs foramina Spinous Most are fork-shaped; Long; point inferiorly Thick; point posteriorly processes lacks a spinous process Appearance (superior view) A schematic illustration shows the superior view of a typical cervical vertebra that has a small, oval body, a triangular vertebral foramen, transverse processes containing transverse foramina, and a spinous process. A schematic illustration shows the superior view of a typical thoracic vertebra with a large heart-shaped body, a circular vertebral foramen, long transverse processes containing articular facets, and a long, pointed spinous process located inferiorly. A schematic illustration shows the superior view of a typical lumbar vertebra with the largest kidney-shaped body, a flat triangular vertebral foramen, short transverse processes with no facets, and a thick, pointed spinous process located posteriorly. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Structure of the Vertebrae (13 of 18) Sacrum— S1  S5 form the posterior wall of the pelvic cavity; Fuse by ages 20–25 Coccyx—Generally composed of 4 vertebrae; Fuse about age 25 Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 Herniated Disc Herniated (Slipped) Disc— Results from trauma, injuries from lifting, or longer-term damage from repeated motions Nerve compression can cause significant pain, numbness, tingling, and muscle weakness Treatments include physical therapy, anti-inflammatory steroid injections, and surgery Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 The Thoracic Cage (2 of 5) Thoracic Cage (continued) Ribs—Includes 12 pairs of ribs and Costal Cartilages, made of hyaline cartilage which provides flexibility; Spaces between ribs are the Intercostal Spaces – Ribs 1–7—...........................................; Attach to the sternum via their own costal cartilage – Ribs 8–12—..................; Do not attach to the sternum directly ▪ Ribs 8–10—.................................—Costal cartilages attach to the cartilage of rib 7 as the Costal Margin ▪ Ribs 11–12—.................................—Do not attach to the sternum Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 The Thoracic Cage (3 of 5) Figure 7.24 The thoracic cage, anterior view. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.3 The Sternum and CP R Cardiopulmonary Resuscitation (CP R) —Life-saving technique administered when an individual’s heart has stopped functional contractions and/or breathing has stopped CP R may restore circulation to the body by the application of repeated compressions to the chest over the sternum Hands must be placed over the center of the sternum, and not over the xiphoid process, which may break and damage underlying organs, particularly the liver CP R may still break the sternum and ribs, especially in elderly individuals with low bone mass Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 The Pectoral Girdle (1 of 5) Pectoral Girdle—Consists of two bones, the Clavicle and Scapula, that support the upper limb Clavicle—S-shaped bone; – Functions like a brace for the upper limb so that it rests laterally to the trunk Scapula—Sits on the posterosuperior rib cage; – Injuries to the A C joint are common and are referred to as a separated shoulder Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 The Humerus (3 of 3) Figure 7.29 The humerus. Humerus—Only bone of the arm (brachium) Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 Bones of the Forearm: The Radius and Ulna (1 of 4) Forearm (Antebrachium) —Consists of a lateral Radius and a medial Ulna Radius—Proximal epiphysis is the Radial Head that articulates with the capitulum as part of the elbow joint and with the ulna to form the proximal radioulnar joint; Forearm (continued) Ulna—Proximal epiphysis The proximal radius and ulna fit with the distal humerus to form the elbow joint Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 Bones of the Forearm: The Radius and Ulna (3 of 4) Figure 7.30 The bones of the forearm: the radius and ulna. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 Bones of the Forearm: The Radius and Ulna (4 of 4) Figure 7.31 The elbow joint. Crossing of the radius and ulna Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 Wrist Fractures (1 of 2) Wrist Fractures—Usually occurs from direct trauma or an attempt to stop a fall with an outstretched arm Commonly involve the distal radius and ulna and possibly the carpals, particularly the scaphoid Fracture to the right is a Colles fracture of the distal radius Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 Wrist Fractures (2 of 2) Wrist Fractures (continued) Common in children and adults ages 60–69 Incidence declines with advanced age while incidence of other fractures, such as hip fractures, increases; May result when people fail to catch themselves Present with pain and swelling over the injured area Some wrist fractures are treated with simple casting while others require surgical intervention Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.4 Bones of the Hand and Fingers: Metacarpals and Phalanges Manus (Hand) —Includes the metacarpals..................... are I V numbered Fingers—Includes 14 total................ Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.5 The Pelvis and Bones of the Pelvic Girdle (1 of 11) Pelvis—Consists of two pelvic bones, the sacrum, which form the oval-shaped Pelvic Inlet with the surrounding bony ridge called the Pelvic Brim, and the coccyx – Pelvic Bone—Composed of three bones that fuse during childhood;................,..............., and................; Symphysis pubis dysfunctio n (SPD) ? Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.5 The Pelvis and Bones of the Pelvic Girdle (9 of 11) Female and Male Pelvis – Female pelvis is generally wider, shallower, lighter, and less robust than the male pelvis Shape of Greater Pelvis – Wide in females and anterior superior iliac spines are far apart with flared iliac crests; Narrow in males, anterior superior iliac spines are close together, iliac crests are straight Coccyx and Sacrum – Male sacrum is longer and narrower than the female sacrum; Female coccyx is situated more posteriorly and is more moveable than the male coccyx Pelvic Inlet and Outlet – Female pelvic inlet is wide and oval; Male pelvic inlet is narrow and heart-shaped; The male pelvic outlet is narrower than that of the female Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.5 The Pelvis and Bones of the Pelvic Girdle (11 of 11) Figure 7.36 Differences between the female and male pelves. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.5 Bones of the Thigh: The Femur and Patella (1 of 3) Femur – Only bone of the thigh Largest and strongest bone in the body Patella – Sesamoid bone Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.5 Bones of the Leg: The Tibia and Fibula (1 of 3) Leg – Consists of a medial Tibia and a lateral Fibula held together by an Interosseous Membrane Tibia – Second strongest bone in the body Fibula The knee joint consists of two articulations – tibiofemoral and patellofemoral. The joint surfaces are lined with hyaline cartilage and are enclosed within a single joint cavity Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 7.5 Bones of the Ankle and Foot: The Tarsals, Metatarsals, and Phalanges (2 of 8) Foot – Includes the Tarsals (7).................... (I-V) Toes – Includes 14 total Phalanges Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved Human Anatomy and Physiology BIOL3306 Fall 2024 Week 3: Muscle Tissue Professor: Nour Nissan Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.1 Overview of Muscle Tissue Muscle Tension—Generation of force by all muscle tissue; creates movement, maintains posture, stabilizes joints, generates heat, and regulates the flow of materials through hollow organs Muscle tissue consists of Muscle Cells (Myocytes) and the surrounding extracellular matrix called Endomysium, which holds the muscle cells together and transmits tension to neighboring cells Muscle types include................,..............., and............... (myo=muscle) (sarco=flesh) Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.1 Types of Muscle Tissue Figure 10.1 Three types of muscle tissue Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.1 Properties of Muscle Cells Contractility is the ability to contract where proteins in the cell draw closer together Excitability (Responsivity) is the ability to respond to a stimulus (chemical, mechanical or electrical) Conductivity is the ability to conduct electrical charges across the plasma membrane Distensibility is the ability of a cell to be stretched without being ruptured Elasticity is the ability of a cell to return to its original length after it has been stretched Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved  9.1 Structure of Skeletal Muscles Gross Anatomy of a Skeletal Muscle Skeletal muscle cells are called Skeletal Muscle Fibers (muscle cell fibers or myocytes) because of their long, thin shape; surrounded by a thin layer of extracellular matrix called.................. Between 10 and 100 muscle cell fibers are bundled together into a group called a Fascicle, which is surrounded by connective tissue called..................... All the fascicles in a muscle are surrounded by another layer of connective tissue called.................... Epimysium is continuous with the most superficial connective tissue sheath, known as the Fascia Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.1 Structure of Muscle Cells Muscle cells have most of the same organelles as other cells, but there are structural differences:....................—The muscle cell’s cytoplasm....................—The muscle cell’s plasma membrane....................—Bundles of specialized proteins, including those involved in muscle contraction..........................................(......) is a modified smooth endoplasmic reticulum that forms a weblike network surrounding each myofibril Figure 10.2 A generalized cell (left) compared with a generic muscle cell (right). Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.2 Structure of the Myofibril Myofibril—Composed of hundreds to thousands of protein bundles called Myofilaments. Many myofibrils come together to make up a myocytes, Myofibril consist of: Contractile Proteins—Produce tension Regulatory Proteins—Control when the muscle fiber can contract Structural Proteins—Hold the myofilaments in their proper places and ensure the stability of the muscle fiber There are three types of myofilaments: Thick Filaments, Thin Filaments, and Elastic Filaments Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.2 Structure of the Myofibril Thick Filaments—Largest diameter; composed of the contractile protein.................... Includes two globular “heads” and two intertwining chains making up a “tail”; the head protrudes from the myosin tail Thin Filaments—Made up of contractile, regulatory, and structural proteins....................—Bead-shaped protein with an Active Site that can bind to a myosin head...........................—Long, ropelike regulatory protein that spirals around the two actin strands so that, at rest, it covers the active sites on actin.....................—Small, globular regulatory protein that consists of subunits that hold the tropomyosin in place; together tropomyosin and troponin help to switch on and off muscle contraction Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.2 Structure of the Myofibril Elastic Filaments—Thinnest filaments; composed of a single massive structural protein called.............., which is shaped like a spring Uncoils when stretched and recoils when the stretching force is removed. Also resist excessive stretching and provide elasticity to the muscle fiber to help it “spring” back to its original length after it is stretched Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.2 Structure of the Myofibril Figure 10.5 Structure of myofilaments. Z-Lines: attachment points for sarcomeres A sarcomere is a segment of myofibril extending from one Z-line to the next Z line Z line Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved 10.4 Skeletal Muscle Contraction Phases of skeletal muscle contraction Excitation Phase—The sarcolemma of a muscle fiber must be stimulated by AC h from a motor neuron to have an action potential Excitation-Contraction Coupling Phase—Transmits the excitation to the parts of the fiber that produce the contraction, the myofilaments, via calcium ions from the SR Contraction Phase—Sliding-filament mechanism occurs and the sarcomere contracts Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved Individual Muscle Cells Contract and Relax Muscle contraction: each sarcomere shortens a little Basic process of contraction 1. Skeletal muscle must be activated by a.................. 2................. activation increases the concentration of...........................in the vicinity of the contractile proteins 3. Presence of..................... enables contractions 4. When................. stimulation stops, contraction stops Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved Nerves Activate Skeletal Muscles Motor neurons stimulate muscle contraction. Acetylcholine (neurotransmitter) is released from motor neuron at neuromuscular junction. Acetylcholine diffuses across neuromuscular junction to muscle cell receptors. Binding of acetylcholine to muscle cell receptors generates electrical impulse within muscle cell. Electrical impulse is transmitted through the cytoplasm. Copyright © 2025, 2019, 2016 Pearson Education, Inc. All Rights Reserved Activation Releases Calcium Electrical impulse triggers calcium ion release. Calcium (Ca ) is released from sarcoplasmic reticulum. Ca initiates chain of events that cause contraction when it contacts the myofibrils. Copyright © 2025, 2019, 2016 Pearso