A&P 1 (Midterm (Chapters 1-8)
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Questions and Answers

What characterizes the mastery stage of learning?

  • Practice and teaching the material (correct)
  • Initial exposure through storytelling
  • Repetitive exposure to material
  • Understanding through group discussions

    • Which learning stage involves strategies such as rewriting notes and using flashcards?

  • Foreign
  • Sequential
  • Familiar (correct)
  • Mastery

    • What does the study of anatomy primarily focus on?

  • The balance of the internal environment
  • The body's chemical reactions
  • The functions of body systems
  • The structure of the body (correct)

    • What is the final level of organization in the human body?

    <p>Organism</p> Signup and view all the answers

    What critical function does the control center serve in homeostasis?

    <p>It determines necessary changes in the body.</p> Signup and view all the answers

    Which layer of the serous membrane directly covers the organs?

    <p>Visceral layer</p> Signup and view all the answers

    What is the primary use of X-rays in medical imaging?

    <p>Viewing teeth and bone</p> Signup and view all the answers

    Which type of bond is characterized by the sharing of electrons between atoms?

    <p>Covalent bond</p> Signup and view all the answers

    Which of the following is true regarding isotopes?

    <p>They are forms of an element with different mass numbers</p> Signup and view all the answers

    What is the function of serous membranes in the body?

    <p>To reduce friction between internal organs</p> Signup and view all the answers

    In which cavity would you find the urinary bladder?

    <p>Abdominopelvic cavity</p> Signup and view all the answers

    Which structure is NOT part of the cranial cavity?

    <p>Spinal cord</p> Signup and view all the answers

    What is the main function of medical imaging?

    <p>To provide internal views of the body for diagnosis</p> Signup and view all the answers

    What type of reaction occurs when larger molecules are broken down into smaller molecules?

    <p>Decomposition reaction</p> Signup and view all the answers

    Which of the following best describes exergonic reactions?

    <p>Reactions that release energy</p> Signup and view all the answers

    What is the primary function of enzymes in chemical reactions?

    <p>Lower activation energy</p> Signup and view all the answers

    What type of molecule is formed when a nutrient is dissolved in water?

    <p>Solution</p> Signup and view all the answers

    Which macromolecule is primarily made up of amino acids?

    <p>Proteins</p> Signup and view all the answers

    What type of lipids are crucial for forming cellular membranes?

    <p>Phospholipids</p> Signup and view all the answers

    Which statement is true regarding the pH scale?

    <p>The pH scale ranges from 0 to 14</p> Signup and view all the answers

    What is the primary function of triglycerides?

    <p>Provide insulation and energy</p> Signup and view all the answers

    What are monomers in the context of organic molecules?

    <p>Individual units that connect to form polymers</p> Signup and view all the answers

    What is the primary function of enzymes in biological reactions?

    <p>Speed up the rate of chemical reactions</p> Signup and view all the answers

    Which of the following best describes the structure of DNA?

    <p>Double-stranded, helical molecule</p> Signup and view all the answers

    During which phase of the cell cycle does DNA replication occur?

    <p>S phase</p> Signup and view all the answers

    What is the role of transcription factors in cellular differentiation?

    <p>They activate specific genes</p> Signup and view all the answers

    What process begins the synthesis of proteins in the cell?

    <p>Transcription of mRNA</p> Signup and view all the answers

    What are sister chromatids?

    <p>Duplicated chromosomes attached at a centromere</p> Signup and view all the answers

    What does ribosomal RNA (rRNA) do during translation?

    <p>Acts as a structural component of ribosomes</p> Signup and view all the answers

    What occurs during the anaphase stage of mitosis?

    <p>Chromatids separate and move to opposite sides</p> Signup and view all the answers

    What term describes cells that have not yet specialized into specific types?

    <p>Undifferentiated cells</p> Signup and view all the answers

    What represents the final stage of mitosis?

    <p>Telophase</p> Signup and view all the answers

    Which part of the sternum is the superior broad section?

    <p>Manubrium</p> Signup and view all the answers

    What is the main difference between true ribs and false ribs?

    <p>True ribs directly attach to the sternum via costal cartilage, while false ribs do not.</p> Signup and view all the answers

    Which of the following statements about floating ribs is correct?

    <p>They have no costal cartilage and do not attach to the sternum.</p> Signup and view all the answers

    At what age does the xiphoid process typically become completely calcified?

    <p>60 years</p> Signup and view all the answers

    What characteristic is true for costal cartilage in relation to the ribs?

    <p>Only true ribs have costal cartilage directly attached to the sternum.</p> Signup and view all the answers

    What is the primary function of cilia in epithelial cells?

    <p>Sweeping materials off the surface</p> Signup and view all the answers

    How do nutrients typically reach the outermost layers of epithelial tissue, given its avascular nature?

    <p>Diffusion from underlying connective tissue</p> Signup and view all the answers

    Epithelial tissue is primarily known for its role in which of the following?

    <p>Secretion and protection</p> Signup and view all the answers

    Which type of gland secretes substances directly into the bloodstream?

    <p>Endocrine gland</p> Signup and view all the answers

    What is the typical characteristic of connective tissue compared to epithelial tissue?

    <p>Contains abundant extracellular matrix</p> Signup and view all the answers

    What primarily composes the cell membrane?

    <p>Lipids, proteins, carbohydrates</p> Signup and view all the answers

    Which type of connective tissue serves the function of connecting bones to muscles?

    <p>Tendons</p> Signup and view all the answers

    Which statement correctly describes phospholipids?

    <p>They are hydrophobic molecules.</p> Signup and view all the answers

    Which cell type is primarily responsible for the immune response within connective tissue?

    <p>Macrophages</p> Signup and view all the answers

    What do microvilli do on the surface of epithelial cells?

    <p>Increase surface area for absorption</p> Signup and view all the answers

    What is facilitated diffusion?

    <p>Movement of molecules from high to low concentration through membrane proteins</p> Signup and view all the answers

    What is the primary role of mitochondria?

    <p>Energy production through aerobic respiration</p> Signup and view all the answers

    What is the main function of adipocytes in connective tissue?

    <p>Store lipids and energy</p> Signup and view all the answers

    What is a key function of the Golgi apparatus?

    <p>Sorting and modifying products for transport</p> Signup and view all the answers

    Which type of cell junction allows no movement between cells?

    <p>Tight junctions</p> Signup and view all the answers

    What describes the cytoskeleton's role in a cell?

    <p>It maintains the cell's structure and organization.</p> Signup and view all the answers

    Which option describes a feature typical of epithelial tissue?

    <p>Highly cellular with minimal extracellular matrix</p> Signup and view all the answers

    What happens in a hypertonic solution regarding water movement?

    <p>Water leaves the cells</p> Signup and view all the answers

    What characterizes peripheral proteins associated with the cell membrane?

    <p>They are attached to either the interior or exterior of the membrane.</p> Signup and view all the answers

    Which type of sweat gland is primarily involved in thermoregulation?

    <p>Eccrine sweat glands</p> Signup and view all the answers

    What is the primary role of sebaceous glands?

    <p>Producing an oily substance called sebum</p> Signup and view all the answers

    Which layer of the skin is primarily responsible for sensation?

    <p>Dermis</p> Signup and view all the answers

    Which of the following injuries affects only the epidermis?

    <p>First-degree burns</p> Signup and view all the answers

    What classification do patella bones belong to?

    <p>Sesamoid bones</p> Signup and view all the answers

    Which function is NOT performed by the skin?

    <p>Production of red blood cells</p> Signup and view all the answers

    Which of these markings indicates a rounded articulating surface?

    <p>Head</p> Signup and view all the answers

    Which of the following is a function of the skin's sweat glands?

    <p>Aiding in thermoregulation</p> Signup and view all the answers

    What defines a long bone?

    <p>It is cylindrical and longer than wide</p> Signup and view all the answers

    Which structure is found at the end of a long bone?

    <p>Epiphysis</p> Signup and view all the answers

    What type of joint movement do Meissner's corpuscles primarily detect?

    <p>Pressure</p> Signup and view all the answers

    Which type of burn affects all layers of the skin, including deeper tissues?

    <p>Third-degree burns</p> Signup and view all the answers

    Which bone cell type is responsible for breaking down bone?

    <p>Osteoclasts</p> Signup and view all the answers

    During which ossification process do mesenchymal cells differentiate into osteoblasts to form flat bones?

    <p>Intramembranous ossification</p> Signup and view all the answers

    Which layer of thick skin is not present in thin skin?

    <p>Stratum Lucidum</p> Signup and view all the answers

    What primarily occurs at the epiphyseal plate to allow bones to grow in length?

    <p>Chondrocytes undergo mitosis</p> Signup and view all the answers

    What type of cells in the stratum basale are responsible for detecting light touch?

    <p>Merkel cells</p> Signup and view all the answers

    What is the role of osteoblasts in bone formation?

    <p>To form the new bone matrix</p> Signup and view all the answers

    What characteristic is associated with the stratum spinosum?

    <p>Football-shaped keratinocytes with spiny projections</p> Signup and view all the answers

    What type of growth allows cartilage to increase in width?

    <p>Appositional growth</p> Signup and view all the answers

    What substance produced in the stratum granulosum contributes to the skin's waterproof barrier?

    <p>Eleidin</p> Signup and view all the answers

    How does exercise affect bone tissue?

    <p>It makes bones thicker and denser</p> Signup and view all the answers

    Which layer of the dermis contains the majority of the skin's blood vessels?

    <p>Reticular layer</p> Signup and view all the answers

    Which structure is NOT part of the axial skeleton?

    <p>Clavicle</p> Signup and view all the answers

    What is a hematoma's role in bone repair?

    <p>It prevents blood loss</p> Signup and view all the answers

    What is the primary component of hair?

    <p>Keratin</p> Signup and view all the answers

    Which hormone stimulates osteoclast activity to increase blood calcium levels?

    <p>Parathyroid hormone (PTH)</p> Signup and view all the answers

    What structure is responsible for oil secretion in the skin?

    <p>Sebaceous glands</p> Signup and view all the answers

    Which layer of the skin is primarily responsible for sensation due to its nerve endings?

    <p>Papillary layer of the dermis</p> Signup and view all the answers

    What is the primary structural unit of compact bone?

    <p>Osteon</p> Signup and view all the answers

    How thick can the stratum corneum be in the epidermis?

    <p>15 to 30 layers</p> Signup and view all the answers

    What is the primary role of Langerhans cells in the skin?

    <p>Assist in immune protection</p> Signup and view all the answers

    Which facial bone is known for forming the lower jaw?

    <p>Mandible</p> Signup and view all the answers

    What is the primary function of paranasal sinuses?

    <p>Add volume without adding weight</p> Signup and view all the answers

    Which cranial bone forms the forehead?

    <p>Frontal</p> Signup and view all the answers

    What is the primary component found in the intervertebral discs?

    <p>Water</p> Signup and view all the answers

    Which bones make up the orbit of the eye?

    <p>Frontal, zygomatic, lacrimal</p> Signup and view all the answers

    What is a bony marking of the occipital bone?

    <p>Foramen magnum</p> Signup and view all the answers

    Which bone is recognized as the only movable bone in the skull?

    <p>Mandible</p> Signup and view all the answers

    What structure allows for the passage of the optic nerve?

    <p>Optic canal</p> Signup and view all the answers

    Which cranial bone contains the external acoustic meatus?

    <p>Temporal bone</p> Signup and view all the answers

    What bony marking is found on the maxillary bone?

    <p>Infraorbital foramen</p> Signup and view all the answers

    Which structure divides the nasal cavity?

    <p>Nasal septum</p> Signup and view all the answers

    Which vertebra allows the head to move in a 'yes' motion?

    <p>Atlas</p> Signup and view all the answers

    Study Notes

    Cell Membrane Structure

    • Separates the cell’s internal environment from the external environment
    • Regulates the movement of materials into and out of the cell
    • Composed of phospholipids, cholesterol, carbohydrates, and proteins
    • Flexible, dynamic structure

    Phospholipids

    • Major structural component of the cell membrane
    • Amphipathic molecules
    • Hydrophilic (“water-loving”) phosphate heads
    • Hydrophobic (“water-fearing”) fatty acid tails
    • Arranged into a bilayer (two layers)
    • Phosphate heads face internal and external environments
    • Fatty acid tails create hydrophobic region within bilayer

    Membrane Proteins

    • Proteins associated with cell membrane add functionality
    • Serve as channel proteins, receptors, enzymes, and in cell–cell recognition
    • Transmembrane, or integral, proteins
    • Span the entire width of the cell membrane
    • Peripheral proteins
    • Do not span the membrane
    • Attached to the interior or exterior of the membrane

    Passive Transport

    • Movement does not require energy
    • Requires a concentration gradient
    • Two forms:
      • Simple diffusion: molecules move from high to low concentration without the use of membrane proteins
      • Facilitated diffusion: molecules move from high to low concentration through membrane proteins

    Active Transport

    • Requires energy to move molecules against their concentration gradient
    • From areas of low concentration to areas of high concentration
    • Primary active transport—uses ATP
    • Secondary active transport—uses electrochemical gradient as energy source
    • Symporters—move two molecules in the same direction
    • Antiporters—move two molecules in opposite directions

    Osmosis

    • The movement of water across the cell membrane
    • Water moves from areas of low solute to high solute concentration
    • Hypotonic solution—less solute outside of cell
    • Water enters cells in hypotonic solutions
    • Hypertonic solution—more solute outside of cell
    • Water will leave cells in hypertonic solutions

    Endocytosis

    • A form of active transport
    • Uses the cell membrane to engulf materials
    • Cell membrane pinches off to form a vesicle and material enters cell
    • Three forms of endocytosis:
      • Phagocytosis
      • Pinocytosis
      • Receptor-mediated endocytosis

    Exocytosis

    • The process of a cell exporting material, or cell secretion
    • Vesicle fuses with cell membrane
    • Contents are released
    • Hormones and digestive enzymes secreted this way

    Internal Components of Cells

    • Major components of the inside of cells include:
      • Cytoplasm—the fluid-like interior of cells
      • Organelles—membrane-bound structures that perform a specific function
      • Cytosol – the gel-like substance within the cytoplasm
        • Contains organelles and molecules needed by cell

    Endoplasmic Reticulum (ER)

    • Endoplasmic Reticulum (ER)—series of channels continuous with the nuclear membrane
    • Rough ER—contains ribosomes
      • Involved in protein synthesis
    • Smooth ER—lacks ribosomes
      • Involved in lipid synthesis

    Golgi Apparatus

    • The Golgi Apparatus—series of flattened sacs
      • Sorts and modifies products from rough ER for transport

    Membranous Organelles for Detoxification and Energy Production

    • Lysosomes—membrane-bound vesicles that contain digestive enzymes
      • Used to breakdown wastes within cell
    • Peroxisomes—contain enzymes used to produce hydrogen peroxide
      • used for detoxification
    • Mitochondria—site of aerobic respiration
      • Responsible for ATP production

    The Cytoskeleton

    • Helps maintain the structure of the cell
    • Organizes cytoplasm of cell
    • Aids in separation during cellular division
    • Composed of protein filaments that provide support
      • Microtubules—made of tubulin
      • Intermediate filaments—made of keratin
      • Microfilaments—made of actin

    Organization of the Nucleus

    • Nucleus houses the DNA of the cell.
    • Most human cells have a single nucleus.
    • Nucleus is surrounded by a nuclear envelope.
    • Nuclear pores allow small molecules to move into and out of nucleus.
    • Nucleolus within nucleus is involved in ribosome production.

    Nucleotide Bases of DNA

    • DNA has a double-helix structure formed by bonds between nucleotide bases.
    • The four nucleotide bases of DNA are:
      • Adenine (A)
      • Thymine (T)
      • Cytosine (C) and
      • Guanine (G)
    • Adenine forms a double bond with thymine.
    • Cytosine forms a triple bond with guanine.

    Histology

    • The study of tissues

    Four types of tissues in the body (location and function):

    • Epithelial tissue—form coverings, linings, and glands
    • Connective tissue—protection and support
    • Muscle tissue—provides movement
    • Nervous tissue—allows communication

    ECM (Extra Cellular Matrix)

    • Is ECM homogenous (the same) all through the body? NO

    Common components of ECM:

    • Collagen: tough, protective protein fibers
    • Proteoglycans: negatively charged protein/carbohydrate molecules

    Cellular connections—attachments between cells

    • Tight junctions—allows no movement between cells
    • Desmosomes—flexible connections that allow some movement between cells
    • Gap junctions—passageways that allow movement between the cells

    Study of tissues via microscopy:

    • Stains used:
      • Hematoxylin binds to DNA and shows up in purple (color)
      • Eosin binds to proteins found in cytoplasm and shows up in pink color

    Epithelial tissue:

    • Difference between epithelium and endothelium
    • Features of epithelial tissue
      • Is it highly cellular? YES
      • Is there ECM present between the cells? LITTLE
      • Can this tissue be considered to be polar? YES
      • What are the two sides of epithelia called? Apical and Basal
      • What is the specialized ECM that makes up the basal epithelium called? Basal Lamina
      • Is epithelial tissue avascular (no blood vessels) or vascular (with blood vessels)? AVASCULAR
      • nutrients reach the outermost layers of the epithelial tissue through diffusion from blood vessels in the underlying connective tissue.
      • Are epithelial cells regenerative? YES
      • Why? Because the cells are constantly being shed and replaced.
      • What are enclosed spaces that are lined by epithelia known as? LUMEN
      • The apical surface of epithelia may have structures called cilia or microvilli on them.
        • The function of cilia is to sweep materials off the apical surface.
        • The function of microvilli is to increase the surface area of the cell.

    Functions of Epithelial Tissue

    • They are the body’s first line of defense from physical, biological and chemical wear and tear.
    • They act as gatekeepers of the body.
      • How do they control permeability and selective transfer?
        • By regulating the passage of substances through their cell junctions.
        • Examples: absorption of nutrients in the small intestine, filtration of waste products in the kidneys.
    • Secretion:
      • The epithelia secrete mucus and specific chemical substances like enzymes.
    • Epithelial cell structure is suited to its function.
      • Epithelial cells that are found in locations with a high degree of diffusion—for example, between the air-filled sacs of the lungs and the blood—are thin and flat to enable diffusion to occur rapidly.
      • Epithelial cells in locations of more friction and intracellular transport are considerably larger, often tall and narrow like a column.
      • Shapes of epithelia:
        • Squamous: thin and flattened
        • Cuboidal: cube-shaped
        • Columnar: tall and narrow

    Glands:

    • A gland is a structure that synthesizes and secretes chemicals.
      • Exocrine gland
        • secretes chemicals onto an epithelium to the outside of the body
        • Often have a duct through which the gland’s secretions reach the epithelium
        • Examples :Sweat glands and the glands of the digestive system
      • Endocrine gland
        • secretes chemicals within the body and bloodstream
        • Always ductless
        • Examples: pituitary, thyroid
      • Structure of glands:
        • Epithelium that surrounds a lumen (the cavity within the gland)
        • cells that secrete the chemicals
        • a duct that carries the secretions away from the gland (for exocrine glands)
      • Mechanisms of exocrine secretions:
        • Merocrine secretion: product is released at the apical surface of the cell via exocytosis
        • Apocrine secretion: a portion of the apical cytoplasm is pinched off and released with the product
        • Holocrine secretion: the entire cell is ruptured and released, along with the product

    Connective Tissues

    • They typically have three common characteristic components: collagen, large amounts of ground substance, and protein fibers
    • Unlike epithelial tissue, which is composed of cells that are closely packed with little or no e_________ space in between them, connective tissue cells are rarely found touching each other and are widely dispersed in the extracellular matrix (ECM).
    • The ECM plays a major role in the functioning of this tissue
    • The major component of the matrix, called the ground substance, is the fluid or material between the cells and protein fibers.
      • Tendons connect Two different tissue types.
      • Ligaments connect one Lone type of tissue.

    Functions of Connective Tissue

    • Connection
      • To connect tissues and organs
    • Protection
      • Specialized cells in connective tissue defend the body from microbes that enter the body
    • Transport of n____, fluids, w______ and chemical m___________
    • Storage: A__________ cells store e________ and help with t________ in_________________ of the body

    Types of connective tissue:

    • Semisolid, flexible connective tissues are typically grouped together in a category known as connective tissue proper
    • Structural connective tissues—bone and cartilage—are grouped together in a category called supportive connective tissue
    • Liquid connective tissues (blood and lymph) are grouped together in the category called fluid connective tissue

    Connective tissue proper:

    • Fibroblasts are fiber makers ; they are responsible for creating the fibers that weave together to form the structure of connective tissue proper
    • Adipocytes are cells that store lipids as droplets that fill most of the cytoplasm
    • Macrophages are large immune cells that wander through tissues searching for waste, debris, or unwanted visitors such as bacteria.
      • When stimulated, macrophages release cytokines, small proteins that act as chemical messengers.
        • Cytokines recruit other cells of the immune system to infected sites and stimulate their activities.
    • Mast cells are immune cells that secrete chemicals in order to activate immune responses.
      • Example histamine.
    • Collagen fibers are flexible but also have great tensile strength, resist stretching, and give ligaments and tendons their characteristic resilience and strength.
      • Hold connective tissues together.
    • Elastic Fibers
      • Contain the protein elastin along with lesser amounts of other proteins and glycoproteins.
      • The main property of elastin is that after being stretched, compressed, or twisted it will return to its original shape.
      • Found in skin and vertebral column
    • Reticular fibers are formed from the same protein subunits as collagen fibers; however, reticular fibers remain narrow in a branching network.
      • They are found throughout the body but are most abundant in the reticular tissue of soft organs, such as liver and spleen, where they anchor and provide structural support to the cells, blood vessels, and nerves of the organ.

    Supportive connective tissue:

    • Cartilage is a semisolid material that is able to offer support and protection to the body while maintaining some flexibility.
      • Chondrocytes are responsible for generating the chondroitin sulfates and other components of the cartilage matrix.
      • Chondrocytes sit within small spaces in the otherwise solid matrix.
        • These spaces are called lacunae (singular = lacuna).

    Fluid connective tissue:

    • In the fluid connective tissues—blood and lymph—cells circulate in a liquid extracellular matrix called plasma.
    • All elements circulating in blood are derived from hematopoietic stem cells located in bone marrow
    • Erythrocytes (red blood cells) transport oxygen and other gasses, increasing the efficiency of carrying gasses in a liquid
    • Leukocytes (white blood cells) are immune cells, defending against potentially harmful microorganisms in the tissues.
      • Platelets are cell fragments involved in blood clotting.
    • Lymph and blood are the two forms of fluid connective tissue.
    • In contrast to blood, lymph is mostly acellular (no cells).

    Membranes

    • The four categories of tissue membranes in the body are
      • Mucus membranes line cavities that open to the external environment.
      • Serous membranes double-layered membranes that surround some organs such as the heart.
        • Help in lubrication and protection from friction.
      • Cutaneous membrane (the skin) helps in preventing desiccation (dryness) and protection from microorganisms.
      • Synovial membranes line joints and contain synovial fluid.

    Tissues of all types are vulnerable to injury and aging.

    • Inflammation is the standard, initial response of the body to injury.
      • Inflammation can be of two types.
        • Acute, or short-term inflammation resolves over time by healing of tissue.
        • However, inflammation that goes on too long, becomes chronic and can have devastating effects on homeostasis.

    Integumentary System

    • The integumentary system is comprised of:
      • Skin
      • Hair
      • Nails
      • Associated Exocrine glands

    Layers of the skin:

    • Epidermis
    • Dermis
    • Hypodermis

    Fascia connect skin to underlying muscles

    EPIDERMIS:

    • Most superficial layer of skin.
    • Made of Keratin squamous epithelial Tissue
    • Avascular (no blood vessels)
    • Contains 4 or 5 layers based on location.
      • Thick skin (5 layers) found in soles of feet and palms of hand
      • Thin skin (4 layers) found in all other places
    • Cells migrate from deepest layer to the superficial layer.
    • Mature cells are called keratinocytes
    • Keratin makes cells tough and water-resistant.

    What are the layers of thin skin?

    • Stratum Corneum
    • Stratum Granulosum
    • Stratum Spinosum
    • Stratum Basale

    What are the layers of thick skin?

    • Stratum Corneum
    • Stratum Lucidum
    • Stratum Granulosum
    • Stratum Spinosum
    • Stratum Basale

    STRATUM BASALE:

    • It is the deepest layer of the epidermis
    • Number of layers:-1
    • Cells actively divide to replace cells in superficial layers
    • Additional cells found in stratum basale:
      • Merkel cells—sensory receptors used for discriminatory touch
      • Melanocytes—produce melanin to protect cells from UV radiation

    STRATUM SPINOSUM

    • Number of layers:8 to 10
    • Keratinocytes are shaped like footballs
      • What gives rise to the name “spinosum”? Pointed ends that look like spines
    • Cells are continually pushed toward the stratum granulosum
    • Langerhans (dendritic) cells provide immune protection

    STRATUM GRANULOSUM

    • Named for its granular appearance
    • Cells begin to flatten and accumulate more keratin
    • Melanin can travel to cells within this layer
    • Cells begin to die at the most superficial layers of the stratum granulosum

    STRATUM LUCIDUM

    • Only found in thick skin
    • Located in palms of hand and soles of feet
    • Composed of tightly packed, dead keratinocytes
    • Cells contain eleidin
      • Eleidin protein functions as a water barrier

    STRATUM CORNEUM

    • Most superficial layer of the epidermis
    • Number of layers: 15 to 30 of dead keratinocytes
    • Cells are shed and lost due to mechanical forces
    • Cells are replaced by cells in deeper layers migrating into the stratum corneum

    DERMIS

    • Forms projections that extend into the epidermis
    • Composed mainly of cconnectivetissue. Also contains:
      • Blood vessels
      • Hair follicles
      • Glands
    • Supports the epidermis with nutrients, strength, and elasticity

    LAYERS OF THE DERMIS

    • Collagen fibers provide strength and structure
    • Elastic fibers provide elasticity
    • The dermis has two layers:
      • Papillary layer (superficial layer)
      • Reticular layer (deep layer)

    Papillary Layer

    • Composed of loose areolar connective tissue
    • Contains dermal papillae that project up into the epidermal layer, the stratum
      • Basale
    • Dermal papillae contain:
      • Blood vessels
      • Nerve fibers
      • Tactile (Meissner’s) corpuscles (Used to detect light pressure)

    Reticular Layer

    • Deepest layer of the dermis
    • Much thicker than papillary layer
    • Made of dense irregular connective tissue
    • Contains
      • hair follicles
      • blood vessels
      • nerves
      • Pascinian corpuscles—cells that sense deep pressure

    Hypodermis

    • Also known as the subcutaneous layer
    • Extends to the dermis
    • Composed of adipose and loose areolar connective tissue
    • Provides insulation and cushioning
    • Highly vascularized

    Accessory structures of the skin include:

    - Hair
- Nails
- Sweat glands
- Sebaceous glands

    Hair

    • Found on most body surfaces except palms of hand and soles of feet (thin skin)
    • Composed of dead, keratinized cells from epidermis
    • Structures associated with hair:
      • Sebaceous (oil) glands—secrete sebum
      • Arrector pili muscle—contract to make hair “stand up

    Anatomy of Hair

    • Components of hair from deep to superficial:
      • Hair papilla—supply blood to hair follicle
      • Hair bulb—deepest portion of follicle
      • Hair root—found between bulb and shaft
      • Hair shaft—visible portion above skin
      • Medulla—c of hair shaft
      • Cortex—surrounds medulla
      • Cuticle—surrounds cortex

    HAIR GROWTH

    • Growth is not continuos
    • Follicles alternate between growth and rest cycles.
      • New growth pushes old hair out of follicle.

    NAILS

    • Composed of keratinized epithelial cells
    • Nail bed
    • Nail body
    • Nail Root
    • Nail cuticle (eponychium)
    • Lunula

    Sweat Glands (Sudoriferous glands)

    • Produce sweat (perspiration) to aid in thermoregulation
    • Two types of sweat glands:
      • Eccrine sweat glands
        • Found all over body
        • Less viscous sweat involved in thermoregulation
      • Apocrine sweat glands
        • Found in groin and axilla (armpit)
        • More viscous secretions
        • May be involved in pheromone release

    SEBACEOUS GLANDS

    • Usually associated with hair follicles
    • Secretes an oily mixture called sebum
    • Lubricates and waterproofs skin
    • Secretion stimulated by hormones released during puberty

    FUNCTIONS OF THE SKIN:

    • Protection
      • Keratin, sebum, and lipids protect against water loss
      • Acidic sweat and macrophages (immune cells) protect against microbes
      • Melanin protects against UV radiation
    • Sensory function:
      • The skin contains different types of sensory receptors found in various layers
      • Meissner’s corpuscles and Pascinian corpuscles—tactile sensations (Touch, pressure, vibration, tickle)
      • Thermoregulation—warm, cool
      • Nociceptors—pain (n_________ en__________)

    Thermoregulation:

    • Sweat helps keep the body cool
    • Increased blood flow to the skin cools body

    Vitamin D Synthesis

    • Ultraviolet (UV) rays activate the precursor molecule to initiate vitamin D synthesis
    • Vitamin D aids in the absorption of calcium from foods in the gastrointestinal tract
    • Necessary for bone growth and immune function

    Skin Injuries

    • Skin is highly vulnerable to injury (abrasions, cuts, burns)
    • Skin is highly regenerative
    • Wound healing may lead to scar
    • Loss of accessory structures (hair, glands)
    • Different consistency to tissue after repair

    Burns

    • Occur when damage is caused by heat, radiation, electricity, or chemicals
    • Skin cells die and can be replaced (regeneration)
    • Different categories of burns:
      • First-degree burns—only affect epidermis
      • Second-degree burns—affect epidermis and dermis
      • Third-degree burns—affect epidermis, dermis, and hypodermic

    Wound Healing (Figure 6.15)

    • Is a multi-step process:
      • Blood clotting
      • Fibroblasts produce new
      • Collagen (granulation tissue)

    Regeneration of Epidermis

    • The epidermis, the outermost layer of skin, can regenerate after injury.
    • Scar tissue may form after healing, depending on the severity of the injury.

    The Skeletal System

    • Composed of bone and cartilage.
    • Bone is a solid connective tissue.

    Bone Functions

    • Provides a rigid support framework for the body.
    • Allows movement through muscle contractions.
    • Protects internal organs.
    • Stores minerals in the Extra Cellular Matrix (ECM).
    • Stores energy in the form of adipose in yellow bone marrow.
    • Produces blood cells through hematopoiesis.

    Bone Classification by Shape

    • Long bones: longer than they are wide.
    • Short bones: approximately equal in length, width, and thickness.
    • Flat bones: thin and curved.
    • Irregular bones: complex shapes that don't fit other classifications.
    • Sesamoid bones: small, rounded bones within tendons or ligaments.

    Long Bone Structures

    • Epiphysis: ends of the bone.
    • Diaphysis: shaft of the bone.
    • Metaphysis: region between the epiphysis and diaphysis.
    • Medullary cavity: hollow space within the diaphysis.
    • Epiphyseal line: remnant of the epiphyseal plate (growth plate).
    • Periosteum: dense irregular connective tissue covering the bone surface.
    • Endosteum: dense irregular connective tissue lining the medullary cavity.
    • Articular cartilage: hyaline cartilage covering joint surfaces, reducing friction.

    Short Bones

    • Examples: carpal bones of the wrist and tarsal bones of the ankle.
    • Provide stability and support.

    Sesamoid Bones

    • Examples: patella (kneecap).
    • Protect tendons from compressive forces.

    Flat Bones

    • Examples: cranial bones (skull), sternum, ribs, and scapula.
    • Protect internal organs.

    Irregular Bones

    • Examples: vertebrae and facial bones.
    • Have complex shapes.

    Bone Markings

    • Distinguishing features on bone surfaces.
    • Articulating surfaces: where two bones meet.
    • Depressions: sunken portions of a bone.
    • Projections: features projecting above the bone surface.
    • Holes and spaces: openings or grooves in the bone.

    Articulating Surfaces

    • Condyle: rounded surface.
    • Facet: flat surface.
    • Head: prominent, rounded surface.
    • Trochlea: rounded, pulley-like surface.

    Projections

    • Crest: ridge.
    • Epicondyle: projection off a condyle.
    • Line: slight, elongated ridge.
    • Process: prominent feature.
    • Ramus: long projection (branch).
    • Spine: sharp process.
    • Trochanter: large, rough, rounded projection.
    • Tubercle: small, rounded process.
    • Tuberosity: rough surface.

    Holes and Spaces

    • Canal: passage within a bone.
    • Fissure: slit through a bone.
    • Foramen: hole through a bone.
    • Meatus: opening into a canal.
    • Sinus: air-filled space within a bone.

    Importance of Bone Markings

    • Identifying bones and their locations.
    • Understanding how bones interact with other body parts.
    • Locating other structures relative to bones.
    • Determining the forces exerted on a bone based on its size and shape.

    Cartilage Tissue

    • Semi-solid connective tissue.
    • Avascular (lacks blood vessels).
    • Covered by perichondrium (dense irregular connective tissue).
    • Perichondrium delivers nutrients to the cartilage through its blood vessels.

    Compact Bone

    • Dense, solid connective tissue.
    • Provides support and protection.

    Bone Cells

    • Osteogenic cells: stem cells that differentiate into osteoblasts.
    • Osteoblasts: bone-forming cells.
    • Osteocytes: mature osteoblasts surrounded by matrix, located in lacunae.
    • Osteoclasts: bone-resorbing cells.

    Compact Bone Structure (Microscopic View)

    • Osteon: structural unit of compact bone.
    • Concentric lamellae: rings of matrix surrounding central canal.
    • Central canal: contains blood vessels and nerves.
    • Perforating canals: connect the central canal to the periosteum.

    Spongy Bone

    • Contains interconnected spaces filled with red bone marrow.
    • Provides strength and houses blood cell production.

    Bone Formation (Ossification)

    • The process of forming new bone tissue.

    • Occurs on a cartilage or membrane template.

    • Intramembranous ossification: bone formation on a connective tissue membrane.

    • Endochondral ossification: bone formation on a hyaline cartilage template.

    Intramembranous Ossification

    • Forms the flat bones of the cranium and face.
    • Process:
      • Mesenchymal cells differentiate into osteoblasts.
      • Osteoblasts secrete osteoid (unmineralized bone matrix).
      • Trabeculae (lattice of bone) and periosteum form.
      • Compact bone surrounds trabecular bone.

    Endochondral Ossification

    • Forms most long bones.
    • Process:
      • Cartilage cells differentiate into osteoblasts.
      • Minerals deposit on collagen fibers at the diaphysis.
      • Perichondrium becomes periosteum.
      • Blood vessels penetrate the periosteum, forming the primary ossification center.
      • Cartilage remains at the epiphyseal plate for longitudinal growth.

    Cartilage Growth

    • Interstitial growth: cartilage grows longer from within due to chondrocyte replication.
    • Appositional growth: cartilage grows wider due to chondroblasts in the perichondrium depositing matrix.

    Bone Growth in Length (Longitudinal Growth)

    • Occurs at the epiphyseal plate.
    • Cartilage on the diaphysis side of the plate is replaced by bone.
    • The process continues as long as cartilage is present at the epiphyseal plate.

    Bone Growth in Diameter (Appositional Growth)

    • Occurs through osteoblast activity at the periosteum.
    • Osteoblasts secrete matrix, increasing bone diameter.
    • Osteoclasts resorb bone lining the medullary cavity, maintaining a balanced growth.

    Bone Remodeling

    • Continuous process of bone breakdown and new bone formation.
    • Key for:
      • Maintaining mineral homeostasis.
      • Adapting bone strength to stress and injury.
      • Repairing fractures.

    Bone Repair

    • Process:
      • Hematoma formation: blood clot at the fracture site.
      • Cartilage callus formation: cartilage template for bone growth.
      • Bony callus formation: cartilage callus is replaced by bone.
      • Bone remodeling: compact bone forms around the fracture site.

    Nutrition and Bone Tissue

    • Calcium: critical for bone strength, stored in the bone ECM.
    • Hypocalcemia: low blood calcium.
    • Hypercalcemia: high blood calcium.
    • Parathyroid hormone (PTH): stimulates osteoclasts, increasing blood calcium.
    • Calcitonin (CT): inhibits osteoclasts, reducing blood calcium.

    Exercise and Bone Tissue

    • Exercise and physical stress strengthen bones.
    • Increased exercise leads to thicker, denser bones.
    • Lack of exercise leads to weaker, lighter bones, increasing fracture risk.

    Directional Terms

    • Superior: towards the head.
    • Inferior: towards the feet.
    • Anterior: towards the front.
    • Posterior: towards the back.
    • Ventral: belly side.
    • Dorsal: back side.
    • Medial: towards the midline.
    • Lateral: away from the midline.
    • Cranial: towards the head.
    • Caudal: towards the tail.
    • Proximal: closer to the origin.
    • Distal: further from the origin.
    • Superficial: near the surface.
    • Deep: farther from the surface.

    Axial Skeleton

    • Forms the central axis of the body.
    • Protects internal organs.
    • Allows movement of the head, neck, back, and respiratory muscles.
    • Consists of 80 bones:
      • Skull
      • Vertebral column
      • Ribs
      • Sternum

    Appendicular Skeleton

    • Forms the upper and lower extremities.
    • Consists of 126 bones.
    • Includes bones that attach the extremities to the axial skeleton.

    The Skull

    • Composed of 22 bones.
    • Divided into:
      • Cranial bones: surround and protect the brain.
      • Facial bones: form the face, nasal cavity, mouth, and orbit.
    • Forms cavities that:
      • Contain soft organs.
      • Reduce the skull's weight.

    Bones of the Skull: Cranial Bones

    • Frontal bone (1): forms the forehead.
    • Parietal bones (2): form the superior, lateral sides of the skull.
    • Occipital bone (1): forms the posterior skull and base of the cranial cavity.
    • Temporal bones (2): form the lateral sides of the skull.
    • Sphenoid Bone (1): forms much of the base of the central skull and parts of the temples.
    • Ethmoid bone (1): forms part of the orbit and nasal cavity.

    Bones or the Skull: Facial Bones

    • Mandible (1): forms the lower jaw.
    • Maxillae (2): form the upper jaw, roof of the mouth, part of the orbit, lateral base of the nose.
    • Lacrimal bones (2): form part of the orbit and house lacrimal glands.
    • Nasal bones (2): form the bony bridge and lateral walls of the nose.
    • Palatine bones (2): form the posterior portion of the hard palate, the medial part of the orbit, and the vertical section of the nasal cavity.
    • Zygomatic bones (2): known as cheekbones, form the lateral part of the orbit.
    • Inferior nasal conchae (2): project into the nasal cavity.
    • Vomer (1): forms part of the nasal septum.

    Cranial Bone Markings

    • Frontal bone: Glabella (space between eyebrows), Supraorbital margin, Supraorbital foramen.
    • Parietal bone: None of note.
    • Occipital bone: External occipital protuberance, Superior nuchal line, Foramen magnum, Occipital condyles.
    • Temporal bone: Squamous portion, Zygomatic process, Mastoid process, External acoustic meatus, Mandibular fossa, Articular tuberculae, Styloid process.
    • Sphenoid bone: Greater and lesser wings, Sella turcica (Turkish saddle), Medial and lateral ptergoid processes.
    • Ethmoid bone: Perpendicular plate, Superior and middle nasal conchae, Crista Galli, Cribriform plate (with olfactory foramina).

    Facial Bone Markings

    • Mandible: Body (central part), Ramus (vertical branch), Angle (junction of body and ramus), Coronoid process, Condylar process, Mandibular notch, Mental foramina, Mental protuberance.
    • Maxilla: Alveolar processes (contain tooth sockets), Infraorbital foramen.
    • Lacrimal Bone: None of note.
    • Nasal bone: None of note.
    • Palatine bone: None of note.
    • Zygomatic bone: Temporal process.
    • Inferior nasal concha: None of note.
    • Vomer: None of note.

    Sutures

    • Immovable joints between cranial bones, filled with dense fibrous connective tissue.
    • Sagittal suture: connects the two parietal bones.
    • Coronal suture: connects the frontal bone to the parietal bones.
    • Lambdoid suture: connects the parietal bones to the occipital bone.
    • Squamous suture: connects the parietal bone to the temporal bone.

    The Orbit

    • Bony cavity that protects the eye and its associated muscles.
    • Contributing bones: frontal, zygomatic, maxilla, ethmoid, lacrimal, palatine, sphenoid.
    • Optic canal: allows entry of the optic nerve.
    • Superior orbital fissure: allows entry of blood supply and nerves to the eyeball.

    The Nasal Cavity, Septum, and Conchae

    • Nasal septum: divides the nasal cavity.
    • Formed by:
      • Perpendicular plate of the ethmoid bone.
      • Vomer.
      • Septal cartilage.
    • Nasal conchae: bony projections covered by mucus membranes.
    • Function: warm, filter, and moisten inhaled air.

    Bones Associated with the Skull

    • Hyoid bone: U-shaped bone in the upper anterior neck, suspended by muscles.

      • Does not articulate with other bones.
      • Coordinates tongue, larynx, and pharynx movements for speaking and swallowing.

    • Ossicles (malleus, incus, stapes): three tiny bones within the temporal bones. Part of the ear.

    Paranasal Sinuses

    • Air-filled cavities within:
      • Frontal bone
      • Maxillary bone
      • Sphenoid bone
      • Ethmoid bone
    • Connect to the nasal cavity.
    • Functions:*
      • Reduce skull weight.
      • Contribute to voice resonance.

    Base of the Skull

    • Anterior cranial fossa: contains the crista galli and cribriform plates.
    • Middle cranial fossa: contains openings for blood vessels and nerves.
    • Posterior cranial fossa: contains the internal acoustic meatus, hypoglossal canal, and jugular foramen.

    Middle Cranial Fossa Openings

    • Superior orbital fissure: passage for nerves to the eyeball, associated muscles, and sensory nerves to the forehead.
    • Foramen rotundum: exit for a major sensory nerve to the face.
    • Foramen ovale: exit for a major sensory nerve to the face.
    • Foraman spinosum: entry for blood supply into the cranial cavity.
    • Stylomastoid foramen: exit for a nerve that controls facial muscles.
    • Carotid canal: entry for blood supply to the brain.
    • Foramen lacerum: no structures pass through this opening.

    Development and Aging of the Skull

    • Skull bones are not fused at birth.
    • Fontanelles ("soft spots"):
      • Allow for skull shape changes during birth.
      • Enable rapid brain growth during infancy.
    • Skull bones fuse by adulthood.

    Vertebral Column

    • Consists of 33 vertebrae, often grouped into five regions:
      • Cervical (7): neck.
      • Thoracic (12): chest region.
      • Lumbar (5): lower back.
      • Sacral (5): fused into the sacrum.
      • Coccygeal (4): fused into the coccyx.

    Vertebral Column Curvatures

    • Four curvatures increase strength, flexibility, and shock absorption.
      • Cervical curve: slight forward bend.
      • Thoracic curve: backward bend.
      • Lumbar curve: forward bend.
      • Sacrococcygeal curve: backward bend.

    General Structure of a Vertebra

    • Vertebral body: main, weight-bearing portion.
    • Vertebral arch: bony arch that encloses the vertebral foramen.
    • Pedicles: bony projections connecting the vertebral arch to the vertebral body.
    • Lamina: bony plates that form the posterior portion of the vertebral arch.
    • Vertebral foramen: opening within the vertebral arch, protects the spinal cord.
    • Transverse processes: projections extending laterally from the vertebral arch.
    • Spinous process: projection extending posteriorly (backwards) from the vertebral arch.
    • Articular processes: projections that articulate with adjacent vertebrae.
    • Intervertebral foramen: openings between vertebrae, allowing passage for spinal nerves.

    Cervical Vertebrae

    • 7 cervical vertebrae:
      • Small vertebral bodies.
      • Transverse foramina for vertebral arteries.
      • Bifid spinous processes (except for C1 and C7).

    Atlas (C1) and Axis (C2)

    • Atlas (C1): first cervical vertebra, ring-shaped.
      • Allows head to move in a "yes" motion.
    • Axis (C2): second cervical vertebra, contains the dens (conical process).
      • Allows head to move in a "no" motion.

    Thoracic Vertebrae

    • 12 thoracic vertebrae:
      • Vertebral bodies increase in size as you go down the column.
      • Long, downward angled spinous processes.
      • Articulate with ribs.

    Lumbar Vertebrae

    • 5 lumbar vertebrae:
      • Largest vertebral bodies.
      • Short, blunt spinous processes.

    Intervertebral Discs

    • Fibrocartilage pads: between vertebrae.
    • Functions:
      • Anchor vertebrae.
      • Cushion vertebrae.
      • Allow movement.
    • Anulus fibrosus: outer ring of densely packed collagen fibers.
    • Nucleus pulposus: inner ring of the disc, composed of water, collagen, and prostaglandins. Acts as a shock absorber.

    Sternum

    • Parts:
      • Manubrium: superior, broad part.
      • Body: medial, long part.
      • Xiphoid process: triangular, distal (lower) part. Remains cartilaginous until age 40, becoming completely calcified around 60.

    Ribs

    • 12 pairs of curved flat bones:
      • Costal cartilage: connects some ribs to the sternum anteriorly.
      • Bony features: head, neck, body, tubercle (small projection), and angle.
      • Costal groove: passage for nerves and vessels.

    Types of Ribs

    • True ribs (1-7): costal cartilage directly attaches to the sternum.
    • False ribs (8-12): costal cartilage does not attach directly to the sternum.
    • Floating ribs (11-12): do not have costal cartilage.

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