Complete Exam 2 Study Guide
Complete Exam 2 Study Guide BIOL 2220
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Clemson University Fall 2016 Human Anatomy and Physiology 1 Exam 2 Tissues Slide 1: Tissues Start with the chemical level of life that makes up cells Cells make up tissues Tissue: 2 of more cells that are either the same or different that function together for a common purpose or tasks Histology: Study of tissues Slide 2: Epithelial Tissue- Covering and lining All free body surfaces of the body are covered with covering and lining epithelial tissue Any part of the body that is exposed to the external environment also have covering and lining epithelial tissue - Mouth Entry to a hollow tube essentially This means that anything inside the tube is considered to be outside the body/external environment - Food that is chewed and swallowed is considered to be outside the body Therefore the hollow tube of the digestive tract will have covering and lining epithelial tissue - In addition to the hollow tube of the digestive tract, the reproductive, digestive, respiratory, and cardiovascular tracts also have covering and lining epithelium Slide 3: Epithelial Tissue- Glandular Glandular epithelial tissue makes up glands Ex: Adrenal gland (Sits on top of the kidney) *Covering and lining and glandular epithelial tissue both look different because they do different things due to their composition Slide 4: Functions of Epithelial Tissue Establish boundaries: - Covering and lining epithelial tissue separates the body from the external environment Protection: - The exterior boundary is a form of protection - Epithelial tissue is the first line of defense that functions in keeping pathogens out of the body Absorption: - Pathogens that do enter the body must be absorbed - Selective absorption occurs in the form of filtration, essential Filtration: - Basically a type of absorption based on size of substances o Smaller things can pass while larger things cannot pass Excretion: - Substances that get into our body have to pass through epithelial tissue - Therefore, substances that go out of the body also have to pass through epithelial tissue (Excretion) Secretion: - Sometimes epithelial tissue produces something to be released - Ex: Glandular epithelium produces secretions from glands Sensory reception: - Epithelial tissue has the ability to respond to stimuli from the environment - All body surfaces have epithelium on it and our bodies have to be able to respond to stimuli in the environment Slide 5: Boundaries of Epithelial Tissue Apical surface: - Free and exposed to the external environment - Superficial surface Basalsurface: - Deep portion - Away from the external environment - Attached to connective tissue underneath it (Why connective tissue is called connected tissue- Connects one thing to another) Tissues will look different based on what their function is (Simple, squamous, etc.) - A tissue in spot of the body can look different in another part of the body Slide 6: Basement Membrane There can be modifications to the plasma membrane - Tissues are composed of multiple cells and the cells have connections between them - Ex: Tight junctions, desmosomes Basal layer of epithelial tissue: - Before the connective tissue (In between the epithelial tissue and connective tissue) there is a basement membrane Basement membrane has 2 components: 1) Basallamina: - Portion just at the basal surface of the epithelium - Stained black and is the thin line - A non-cellular sheet of glycoproteins (Proteins with carbohydrates extending off) that can be used to attach to other things Basal lamina is an anchor/adhesive sheet of protein essential to hold the epithelial sitting on top of the connective tissue in place - Basal lamina also acts as a selective filter because the proteins could also be channel proteins Important because all living cells need to be supplied with blood but epithelial tissues are avascaular (Contain no blood vessels) o Important for the blood to be delivered to the basal cells of the epithelium in the connective tissue where it passes from the connective tissue out through the basal lamina to reach the epithelial tissue because: Blood is needed for glucose delivery, picking up waste such as carbon dioxide, etc. 2) Reticular lamina: - In the picture, it is where the arrow is located Blurry, yellow-orange region - The reticular lamina is a collection of collagen fibers - Collagen is the most abundant protein in the body (Connective tissues in general have a lot of fibers in them that could be collagen, reticular, etc.) o Collagen functions in providing strength to tissues o Elastic fibers function in providing stretch and flexibility o Reticular fibers: Function as a mesh network that holds things together - There are collagen fibers that strengthen the attachment between the epithelium and underlying reticular lamina - Overall: Reticular lamina is filled with collagen fibers for strength and attachment Slides 7-11: Covering and Lining Epithelium Can classify covering and lining epithelium based on the number of cells present in the tissue Simple epithelium: - Only have 1 layer of cells - Function in absorption and filtration - Does NOT really provide a lot of protection or other functions - Located in areas not exposed to a lot of wear and tear or friction Otherwise, simple epithelium would break apart Stratified epithelium: - More than 1 layer of cells - Major function is protection in areas exposed to a lot of wear and tear and friction - Located on the surface of the skin - Skin is thin on the head and thick on the feet due to how much pressure they’re exposed to - Name stratified epithelium based on the cells located at the apical surface Pseudostratified epithelium: - Only 1 cell layer thick but it looks like more than 1 layer due to the nuclei appearing as if they are everyone and not just located at the basal portion of the single cell layer - Found in parts not exposed to a lot of movement such as the lining of the respiratory tract Not a lot of friction or change in shape occurs here Can also define covering and lining epithelium based on the shape of the cells Squamous epithelium: - 1 cell layer of flat cells Cuboidal epithelium: - Box-like or cells that have the width the same as the height Columnar epithelium: - Column-shaped or cell that are taller than they are wide Transitional epithelium: - Cells are shaped like domes on the apical surface - Line hollow cavities such as the urinary bladder - When the bladder is empty, cells are dome-shaped, but as the bladder starts to fill up, the cells change to a flattened shape to allow more space in the cavity without changing the size of the cavity - As soon as stretch occur on the urinary bladder, a signal is sent to the brain for the bladder to empty itself, and the flattened cells transition back to the relaxed dome- shape again Slide 12: Glandular Epithelium Compose glands Gland: Cell or group of cells composed of glandular epithelium that secrete substances into ducts that takes the secretion to where it should be, onto surfaces of cells, or into the blood for it to travel elsewhere to do something Where they secrete their substances depends on the type of gland It is possible for there to be unicellular glands in the body Energy is required in order to make a secretory product and to secrete it (Via packaging the secretion up somehow and getting it out of the epithelium) Most glands produce a water-based secretion (Some will be fat-based though) Slides 13/14: Types of Glands Exocrine: - Glands that secrete into a duct - Secretion from the glandular epithelial tissue is secreted into a duct that moves from high to low concentration to have its effect somewhere else - Some exocrine glands secrete only onto the exterior cell surface where it collects o Ex: Goblet cells - Ex: Sweat glands and gallbladder Endocrine: - Glands that do not secrete into ducts - Secrete hormones that travel in the blood stream to go somewhere else - Ex: Thyroid gland and pancreas- Unique because it has exocrine (Duct delivers secretions to small intestine) and endocrine (Secretes hormones to regulate blood sugar in the blood stream) functions Slide 15/16: Structural Classification of Glands Unicellular: - Look at the number of cells that make up the gland—Some glands can be unicellular - Picture: o Goblet cells are part of the digestive system that are unicellular mucous glands o Goblet cells produce mucous o Mucous: Secretion of a mucous gland that secretes mucin protein o Mucous goes to the surface on the lining of the GI tract and prevents digestion of the body’s own digestive track - Respiratory tract: o Secretes mucous on the surface of cells o Any particles in the air will stick to the mucous and won’t reach the lungs *Both functions of mucous secretions are protective Multicellular: - Have more than 1 cell - Makes the difference between simple duct structure with no branches and the compound duct structure with branching o As a result, one can further classify multicellular glands into different groups Slides 17/18: Functional Classification Glands can also be based on how the cell releases its product and not just on where it goes Merocrine glands: - Cells produce secretory products that get packaged in the Golgi apparatus in a vesicle Secretory products get released from the vesicle and cell via exocytosis into the duct where it travels where it needs to go - Key points: o Merocrine gland cells are not damaged and still intact after the release of secretory products o Merocrine gland cells stay around to continue to produce more secretory products - Ex: Salivary glands, sweat glands, and the pancreas all use merocrine form of activity Holocrine glands: - Cells produce secretory products that get stored in an inclusion - Whole cell then sloughs off into the duct where it then bursts open to release its contents - Key point: o Holocrine gland cell dies in the process of releasing secretory products o Have to replace holocrine gland cell via mitosis as a result - Ex: Sebaceous glands (Oil glands associated with hair) use holocrine form of activity Slides 19/20: Connective Tissue All connective tissue is derived from the same embryonic tissue, the mesenchyme (Middle embryonic layer) although they don’t all look like each other 4 basic classes of connective tissue: a) Connective tissue proper: Areolar, dense regular, and elastic connective tissues b) Cartilage: Elastic cartilage, fibrocartilage, and hyaline cartilage c) Bone: Hardest tissue of the body d) Blood: Only liquid tissue of the body *All contain same structural elements Slide 21: Structural Elements All connective tissue classes have the same structural elements: a) Ground substance: - Background substance - Bone: Hard because it is calcified - Blood: Liquid due to the plasma portion of the blood b) Fibers: - Located in the background in the fiber matrix - Large collagen fibers provide strength - Reticular fibers allow stretch c) Cells: - All connective tissues have their own specific types of cells - Ex: Fibroblasts in areolar connective tissue Slide 22: Muscle Tissue Muscle tissue cells are modified for contraction All types of muscle respond to stimuli by getting shorter (contracting) Includes: Muscle tissue is found in the lining of the digestive tract, heart, smooth muscle, and skeletal muscle give local motion When muscle contracts, movement occurs - Ex: Heart muscle tissue: o Contraction of the heart makes blood move - Ex: Smooth muscle tissue: o Contraction pushes a meal through the digestive tract When muscle tissue contracts, heat is generated (Although mot heat that is generated is through metabolic action through the food consumed) - Specifically, shivering is an example that requires muscle tissue and contracts to generate heat All muscle tissue contains: - Sarcolemma: Plasma membrane of a muscle cell made up of a phospholipid bilayer - Sarcoplasm: Cytoplasm of a muscle cell Slides 24-27: Muscle Tissue Types Overall classification criteria used to differentiate one type of muscle from another: - Striations - Nervous control- Voluntary or involuntary - Number of nuclei SkeletalMuscle Tissue: - Striated - Each muscle fiber is a muscle cell that all run right next to each other very compactly and look like lanes on a highway - Multi-nucleated - Embryological development: o One cell emerges with another one then another one emerges so that eventually they all combine Nuclei in the muscle cells end up getting pushed towards the edges and are not located in the middle of the cell - Voluntary Human is able to determine when and how much skeletal muscle tissue contracts - Summary: Skeletal muscle tissue is striated, multi-nucleated, and voluntary Cardiac Muscle Tissue: - Striated - Uni-nucleated - Involuntary contraction and movement - Contain intercalated discs: o Communicating junctions that are located between neighboring cells o Specifically: Channel protein of one cell + channel protein of another cell fuse together to create a connexon, which ultimately creates a gap junction (Communicating junction) o Important because if the composition is changed in one of the neighboring cells, that certain component that was changed can also be put in the connected neighboring cells AKA all are linked together Ex: Muscle contracts when it is excited Stimuli that excites one cell is shared with the other connected cells down the line o Overall: Cardiac tissues contracts as a unit due to intercalated discs rather than just as individual cells Smooth Muscle Tissue: - Smooth and NOT striated - Uni-nucleated - Nuclei appear stretch in individual cells - Appears similar to dense regular connective tissue - Involuntary contraction and movement Slides 28-20: Nervous Tissue Neurons: - Allows the human body to detect stimuli - Turn stimulus energy into electrical energy that is then communicated throughout the body - 50% of nervous tissue is consisted of neurons (Cells) that create electrical impulses Neuroglia: - Rest of the nervous tissue in the background is made up of neuroglia, which means “nerve glue” - Cells that function in holding all the neurons together + function in support and protection (Protects the impulse created by the neurons) Slide 29: Summary of Tissue Types Epithelial Connective Muscle Nervous Membranes Slide 2: Membrane Membrum is Latin for “limb” Slide 3: Definition of Membrane Continuous multicellular sheets composed of at least 2 tissue types - Epithelium bound to underlying connective tissue - Exception is non-covering or non-lining membranes o Ex: Synovial membranes Found between bones at a joint Don’t have epithelial tissue Only have connective tissue Alternative explanation: - By definition, a membrane is an organ since it is composed of at least 2 or more tissue types - Usually 1 tissue is an epithelial tissue that is bound to an underlying connective tissue layer - Basement membrane: Epithelial tissue that is attached to a basement membrane is an example of a whole membrane - Exception: Slides 4-13: Covering and Lining Membranes Cutaneous membrane: - Skin located on the exterior surface of the body - Keratinized stratified squamous epithelium attached to dense irregular connective tissue o AKA squamous epithelium is modified to where it becomes keratinized - Exposed to air - Is dry - Living and dividing tissue of the skin is located at the stratum basale of the epidermis o When cells divide at the stratum basale, they produce keratin protein that accumulates in the cell o Eventually, the cell produces so much keratin that the cell is no longer able to do much else Nucleus and organelles are deleted as a result, and the keratinized cells are now dead cells o Keratin protein is a tough and thick protein that provides strength and protection for the cutaneous membrane (Physical barrier) - 80% of dust is composed of sloughed off keratinized epithelial cells - Overall: A thick layer of dead keratinized squamous epithelium makes up the surface of the cutaneous membrane that provide strength and protection to anything that lies underneath it Mucous membrane: - Mucous glands produce mucous therefore mucous membranes produce some sort of moisture - Most mucous membranes contain stratified squamous or simple columnar epithelium attached to areolar (Loose) connective tissues - Line internal body cavities that are open to the exterior o Found inside the stomach, esophagus, trachea, etc. These all are considered to be open to the exterior and are therefore outside the body - Mucous membranes function in absorption and secretion Serous membrane: - Everything inside the body appears moist - Composed of simple squamous epithelium resting on areolar (loose) connective tissue - Lines closed ventral body cavities - Moist Can see serous membranes on flesh, and when it is pulled away from the cavity, it is located on top of organs inside the cavity - Produces serous fluid: a) Moist fluid that comes in part from leakage of capillaries that run through connective tissue o Fluids from capillaries permeate out of the capillaries and collect at that point b) Simple squamous epithelium produces and secretes hyaluronic acid that is fluid and rich in carbohydrate that makes the fluid viscous (Slippery) *Both fluid from capillary leakage and hyaluronic acid make up serous fluid - Serous fluid is necessary so that the outside body can twist and not pull/tug on organs along with it Serous fluid functions in providing lubrication to allow movement - Serous membranes create a double layered membrane where one layer covers the cavity and the other layer covers the organs to allow movement through the serous fluid that is produced between the two membranes a) Parietal serous membrane: o Belongs to the cavity b) Visceral serous membrane: o Belongs to organs Serosae:Types of Serous Membranes - Named based on location 1. Pleura: - Serous membrane associated with the thoracic cavity - Parietal pleura: o Lines the thoracic cavity - Visceral pleura: o Makes up the outer covering of the lungs - Fluid between the parietal and visceral fluid is called the pleural fluid o This specific serous fluid is important in allowing us to breathe o When the chest changes shape, it pushes back and forth so the pleural fluid helps in preventing the lungs from being crushed o Pleural fluid also allows air to move in when the volume of the lungs changes 2. Pericardium: - Serous membrane that surrounds the heart - Parietal pericardium: o Cavity itself - Visceral pericardium: o Very outer lining of the heart - Fluid between the parietal and visceral pericardium is the pericardial fluid that functions in preventing friction when the heart beats 3. Peritoneum: - Serous membrane of the abdominal pelvic cavity - Parietal peritoneum: o Wall of the abdominal cavity - Visceral peritoneum: o Covering of abdominal organs Slide 14: Synovial Membranes Contains no epithelium Lines cavities of joints - Located where 2 bones come together Secretes synovial fluid in the cavities of joints - Functions in acting as a cushion to prevent bones from digging into each other as one bends and moves - Also lubricates joints so that 2 bones can pass over top of each other without friction Fluid leaking out of the cavity would lead to rubbing of the bone Slide 15: Tissue RelatedDefenses Mechanical barrier: - First defense of covering and lining epithelium - Prevents substances from getting out - Cutaneous membrane: o Prevents substances from getting through the skin - Mucous membrane: o Open to external environment o Prevents substances from getting into the body Cilia: - Function as traps - Ex: When breathing, small particles get trapped in the cilia that push them towards the throat to make you cough Chemical barriers: - Ex: Tissues that line the stomach o Produce acidic environments o Acid in stomach breaks down proteins, bacteria, and other pathogenic microbes - Ex: Female reproductive tract: o Vagina contains an acidic environment o Functions in protecting the uterus from bacteria If these barriers are breached, inflammation will occur Second level of defense - If there is enough breaching, specific immune defenses with B and T cells will come into play Slide 16: Tissue Repair If there is damage to the skin and the epidermis, deeper connective tissue and the blood vessels that run through the connective tissue, there is a series of events to allow healing process to occur Tissue repair will go through 2 processes: a) Regeneration: - Where the tissue damaged is replaced with the same kind of tissue - Cell division is stimulated in in-tact and living tissue that isn’t damaged—Related to many CPK’s,MPF’s etc. Undamaged cells continue to divide until contact inhibition shuts off cell division - Summary: Tissue produces copies of itself and regenerates b) Fibrosis: - Accumulation of fibrous proteins in the tissue - Because the tissue is damaged, the area is weak Fibrous proteins provide strength Fibrous connective tissue may develop in damaged tissue area - An over accumulation of fibrous connective Production of a scar (Where the damaged tissue is NOT replaced with the same tissue but is instead replaced by fibrous connective tissue) - Again: Natural part of healing Have to have an accumulation of the fibrous connective tissue at the site of damage to create a framework to allow the healing process to start, but if it continues and the other original tissue isn’t replaced, scar tissue develops that doesn’t have the same properties as the original tissue - Most tissues are resistant to overproduction of fibrous connective tissue but some tissues are poor at regeneration so most of what they do is the process of fibrosis - Ex: Damage to cardiac muscle Generally turns into scar tissue that doesn’t contract Weaker part of the heart Slide 17-20: Steps of Normal Healing Process 1. Inflammation: - Overview of steps: o Chemicals released by injured tissue cells, macrophages, and mast cells o Capillaries dilate and become permeable o White blood cells and plasma fluids leak into injured area o Clotting protein construct clot o Scab forms - Occurs membranes are breached, inflammation results - Damaged tissues release some chemicals that attract macrophages and mast cells that are circulating in the blood stream (Chemotaxis) Accumulation of macrophages (Phagocytic cells) and mast cells attack foreign substances - Damaged tissue causes the capillaries in that area to dilate so that they become more permeable and allow things like mass cells, macrophages, other white blood cells, and other proteins such as clotting proteins in the plasma to leak out of the capillaries better and provoke healing - Clotting proteins in the plasma cause the formation of a blood clot by sealing the hole + they function in preventing anything else foreign from getting into the damaged area - Blood clot will eventually dry up and become a scab - Beneath the scab a series of events occurs that allow it to be eventually released o Important not to pick at scabs because this will cause and promote the over production of fibrous connective tissue that will lead to scar tissue formation Vitamin E and time can help with the fading of scars since the process of tissue regeneration can take a while sometimes - Review: o Leakage of chemicals Inflammation Capillaries dilate + fluids leak + accumulation of cells at site of damage Swelling = Edema, which is an accumulation of those fluids o Blood clot stops the loss of blood and prevent other pathogens from getting past + holds edges of the cut in place (Harder to heal when if the damaged tissue is constantly moving) 2. Organization events: - When tissue is damaged, capillaries are destroyed and sometimes bigger vessels too so blood supply has to be restored to bring about repair - The blood clot that is in place is then replaced by granulation tissue o Appearance at this point: Granulation tissue looks light pink and looks different than the surrounding tissue o It contains many elements such as proteins and fibroblasts in it o With the granulation tissue present, next a lattice starts to form that can be used as a framework for building This is what ultimately becomes a scar if proper regeneration of the original tissue does not occur - Next, the new capillary bed is established - Fibroblasts of granulation tissue start to close the margins of the wound a) Fibroblasts (cells) secrete growth factors b) Fibroblasts produce specifically collage fibers here that attach to one another and pull the edges together - As the tissue is starting to grow and is present, it is next time to get rid of the blood clot through dissolving/digesting it via macrophages (Phagocytic cells) - More collagen gets deposited and continues to do so until the blood clot is completely replaced by granulation tissue This signals the end of the organization events Regeneration and fibrosis come next 3. Regeneration and fibrosis: - The framework has been created by granulation tissue - Now cells can divide and the granulation tissue can be replaced by regeneration tissue that is supposed to be there and not have a scar develop via excessive fibrosis Factors that mediate tissue repair: Nutrition - Have to intake enough protein to be able to produce the proteins that are used for production of collage fibers and other components o Eat protein Broken down to AA Used to build new templates for protein in cells - Vitamin A: Stimulates epithelial repair - Vitamin B: Stimulates tissue repair in the heart and nervous system o Pregnant females: Pre-natal vitamins are usually rich in vitamin B because good circulatory and nervous system development is necessary for the baby - Vitamin C: Connective tissue and blood vessel repair - Vitamin D: Bone repair - Vitamin E: Prevents scarring - Vitamin K: Blood clotting importance Slide 21: Embryonic Tissue Development All connective tissues have the same embryonic origin of the mesenchyme Fertilized egg Zygote Solid ball of cells that eventually becomes a hollow ball of cells known as a blastula Starts to invigilate via gastrulation to produce gastrula - Have an outer, middle, and inner layer of cells at this point in the embryo = 3 embryonic germ layer due to the pushed in part of the hollow blastula a) Ectoderm: Outer layer b) Mesoderm: Middle layer c) Endoderm: Inner layer - Epithelial tissues come from all 3 germ lays o Epithelial tissue that lines the inside and outside are produced by the middle layer (Mesoderm) to make glandular epithelium o Mucous membranes Endoderm (Inside of body) o Epidermis Ectoderm - Muscle tissue Mesoderm; Same origin as connective tissue but doesn’t have a matrix or cellular fibers - Nervous tissue Ectoderm; Ability to detect things around us + gives CNS Integumentary System Slide 2: Organ System Group of organs that operate collectively to perform specialized functions Review: - Organ systems are a group of organs that function together The functioning of the organ system is due to the organs that make it up - Function of the organ is dependent on the tissues - Function of tissues are due to cells that continue to perform their specialized tasks in the organ system Slides 3/5: Integumentary System Includes the skin + skin derivatives: Hair, nails, glands, and receptors Slide 6: Skin Factoids Skin covers the entire body and is the largest organ Cutaneous membrane: - Dry - Composed of epithelial tissue Skin is 7% of the weight of the average human/total body mass Weighs 9-11pounds Barrier that regulates the exchange from inside and outside the body - Has a surface area between 1.2-2.2 square meters (Actually is a relatively small surface area compared to others) Varies in thickness from 1.5-4.0mm Depends on how much friction the body part is exposed to - Thinnest on the head - Thickest on the soles of the feet Slide 7: Regions of the Integument Epidermis: - Portion of the skin - Made up of stratified squamous epithelial tissue - Major function is protection - Does not have any blood vessels—Blood supply is dependent on the vascularized dermis Dermis: - Portion of the skin - Deep to the epidermis - Made up of fibrous connective tissue Tissue that is composed of many fibers, meaning that the tissue could specifically be dense irregular connective tissue, areolar (loose) connective tissue, or any other connective tissue that is rich in fiber - The dermis is composed of at least 2 types of connective tissue - Vascularized and supplies the epidermis with blood (Also related to skin color) - Changes as aging occurs Amount of fibers (Protein that make up the fibers) get reduced, which lead to loss of elasticity in the skin Hypodermis: - NOT a portion of the skin - Technically beneath the skin - Made up of mostly adipose tissue - Helps with protection of things found underneath the skin (Doesn’t protect the skin itself) since adipose functions like a cushion - Technically hypodermis is superficial fascia Part that covers muscle underneath the skin - Especially changes as aging occurs (So does dermis) Hypodermis’ adipose tissue increases with age since more and more fat gets stored Slide 8: Epidermal Cells Stratified squamous epithelium makes up the epidermis Keratinocytes: - Cells that make up the majority of the epidermis - Undergo keratinization Start out as normal cells but they produce keratin that collects inside the cell and accumulates enough so that the cell loses the nucleus, cytoplasm, and organelles Cell dies All that’s left is the keratin that functions in physical protection - Germ cells are located at the bottom layer of the epithelium and epidermis at the basal layer Germ cells are actively dividing cells that go through mitosis and produce new cells (Yellow cells in the picture- Most cells in the epidermis) - As germ cells divide, the cells on top of the new cells get pushed upward o AKA: Deep cells replicate deeply and push more superficial cells to the surface - As germ cells reproduce Ultimately die and these dead cells located on top of the skin slough off and get replaced by the new cells - 2 weeks: Amount of time it takes cells to reproduce and produce new cells at the basal layer to when the cells are dead and are composed only of keratin and are sloughed off at the surface of the skin (Process of keratinization and loss of cell) - 25-45days: Amount of time for the epidermis to be entirely replaced Melanocytes: - Melanin producing cells (Gray in the picture) - Melanin is a pigment - Melanocytes are in the deep layers of the epidermis where melanin is stored in inclusions and causes darkening of the skin - Tanning: Melanin is produced by melanocytes and the skin gets darker - The darker the skin, the more melanin is produced - Functions in chemical protection Langerhan’s cells: - Produced in bone marrow o Bone marrow: Where blood and blood cells are produced; White blood cells function specifically in immune function - Migrate to the epidermis - Special cells that provide immune function for the skin - The skin is a phenomenal protective barrier that prevents foreign substances from getting into the body, but if there is a breach, the Langerhan’s cells are there to attack foreign substance and prevent them from getting into the body - In summary, Langerhan’s cells function in biological immune protection MerkelCells: - Located deep in the epidermis - At the very bottom layer of the epidermis at the border between the epidermis and the dermis, there are sensory receptor cells called Merkel cells that respond to light touch - Present due to an evolutionary perspective: Allows the body to feel crawling bugs Slide 9: Epidermal Layers (Thin Skin) Thin skin has 4 epidermal layers Stratum basale: - AKA stratum germinativum - Deepest epidermal layer (At the bottom of the epidermis of the skin) - Function: o Single layer of cells that are germ cells (Retain the ability to divide) that maintains the ability to go through mitosis and replicate o Basale cells divide and push everything forward towards the surface of the epidermis and eventually are sloughed off Replaced all over again Stratum spinosum: - Superficial to the stratum basale - Spinosum is Latin for “Prickly” - These cells are the ones that accumulate the keratin proteins + have a webbed-like system of intermediate filaments inside their cells that attach to desmosomes (Anchoring cells that function in resisting tension and friction Helpful when a force is applied overall to multiple cells - Spinosum cells shrink as they age Desmosomes stay attached as they shrink This is what makes the stratum spinosum look prickly Stratum granulosum: - Superficial to the spinosum - 3-5layers of cells that contain granules Granules mean that the cell has produced something and put it in a vesicle to be stored (A vesicle stored substance) - Represents the last of the living cells of the epidermal layers Anything superficial to the stratum granulosum is dead - Types of granules that can be contained in granulosum cells: 1) Kerato-hyaline granule: o Store keratin (Tough protein that protects everything underneath it) 2) Lamellated granule: o Contains glycolipids o Lipid portion: Stained darker than anything else; Accumulation of lipids is like a water proofer Doesn’t function in preventing water from getting in from the outside but instead it helps slow down water loss from the inside to the outside (Due to lipids’ hydrophobic properties) o Prevent us from desiccating and drying out through losing too much fluid Stratum corneum: - Horny layer - 20-30layers of dead cells that are stacked on top of each other Dead cells contain packets of thick keratin (Composition of the outside of a horn- Why it’s called the horny layer) - Provides protection Slide 10: Epidermal Layers (Thick Skin) In thick skin, there is an extra layer between the Stratum granulosum and the Stratum corneum called the Stratum lucidum Found on the palms of the hands, soles of the feet Generally in high friction areas In all, the epidermal layers from bottom to top are: 1. Stratum basale 2. Stratum Spinosum 3. Stratum lucidum 4. Stratum corneum Slide 11: Dermal Layers Located deep to the epidermis The epidermis does not make a very flat layer that goes evenly across the dermis It has an irregular surface that functions in helping to hold the epidermis and dermis together better so it won’t separate as easily Dermis is composed of 2 layers: 1. Papillary Layer: - Composed of areolar connective tissue that holds the epidermis together to the dermis Does so by the fibers reaching up and holding things in place 2. Reticular Layer: - Composed of dense irregular connective tissue that is deep to the papillary layer Dermis extends up into the margin of the bottom of the epidermis Extensions are referred to as dermal papillae (These are irregularities) Slide 12: Developof the Integument Epidermis: Ectoderm - Surface of the body - Derived from the ectoderm (Outer embryonic germ layer) Dermis: Mesoderm - Made up of areolar connective tissue (Areolate connective tissue) and dense irregular connective tissue (Reticular layer) Hypoderm: Mesoderm - Made up of adipose tissue *All connective tissues are derived from the mesoderm Slide 13: Skin Color is Determined by Pigments Melanin: Epidermal - Gives dark colors - Epidermal pigment produced by melanocytes that accumulates in the epidermis - Exposure to the sunlight can change the amount of melanin in the epidermis This is due to a reaction to melanocytes that respond to UV light by producing the melanin - Process: o UV radiation stimulates the melanocytes to produce tyrosinase enzyme o Tyrosinase catalyzes the conversion of tyrosine (AA) Melanin o If there is a genetic condition where tyrosinase can’t be produced No skin color Carotene: Dermal - Dermal pigment that results in a yellow-orange color that is predominantly seen in Asian populations Hemoglobin: - Blood pigment - Blood vessels are located in the dermis, and if there aren’t any other pigments found in the skin Hemoglobin will give the skin a pinkish-white color The color of any individual skin is due to the combination of multiple pigments that are produced (NOT due to a single gene trait) - Fair skin: Low in the production of pigments - Hispanics: Mix melanins - Native Americans: Reddish Slides 14/15: Surface Features Ridges: - Found on the surfaces of fingers and toes - On the epidermis are folds that actually occur in the dermis - Ridges are determine genetically No2 people have the same ridges on their fingers expect identical twins - Function in given fingers and toes better grip and increase friction - If fingers and toes were smooth, humans would not be able to grab things Provides better dexterity in grabbing things - Ridges hold oils that are located on the surface of the skin When you touch something, some of the oil is left behind, which leaves a fingerprint o Ridges, whirls, deltas Grooves: - Appear all over the surface of the body - Picture in slide was taken on the back of hand on the thumb and forefinger - Grooves are shown that make diamonds Surface of the skin is covered with diamonds - Areas where there is hair: o Hair grows out of the intersection of diamonds and not out of the middle - Groove explanation related to evolution: o Humans started out as dinosaurs that had scales all over their bodies o As evolution occurred, the grooves were left over from when there were scales on the body o The scales were made out of keratin that covered the outer surface of the body Slides 16-27: Skin Appendages Sudiferous glands: Sweat glands a) Eccrine: - Sweat glands that cover most of the outer surface of the body - Function throughout life Means babies can sweat - Main function is therefore thermoregulation Water vaporizes and the body temperature cools b) Apocrine: - Found only in high saturation areas under arms and between legs in high friction spots - NOT involved in thermoregulation - These sweat glands don’t begin functioning until around puberty (Require hormones to be triggered) - Lubrication is needed in preventing from skin rubbing and chaffing - Secretions from the apocrine sweat glands are odorless Smell is due to bacteria that feeds on the secretions and they produce an odor c) Ceruminous: - The production of cerumen (wax) occurs in the ear canal - Ceruminous sudiferous glands are only found in the ears - Modified apocrine gland - Cerumin functions in protecting the inner ear by trapping foreign things in order to prevent disruption of hearing - Cerumin can also function in being a sound deadener When the ear is exposed to loud voices, for example, cerumen production increases d) Mammary: - Modified apocrine gland - Produce milk AKA produced modified sweat that is rich with proteins, fat and some sugar (Lactose) Sebaceous glands: - Produce sebum that is a lipid-based secretion (An oil) called sebum - Typically associated with hair follicles o Sebaceous glands produce an oil that coats the hair to keep it supple and not brittle o Oil allows the hair to be bendable and pliable without snapping - Oil that is produced by the sebaceous glands also collects on the surface of the skin and acts as a lubricant and prevent water loss so the skin won’t become dehydrated - Oil gets trapped by pathogens and bacteria Functions in protection - Sebum (oil) has bactericidal properties Immunological function - Sebaceous glands respond to hormonal secretions like androgens and testosterones Therefore, a lot of sebum production is see when boys hit puberty Nails: - Scale-like modifications of the epidermis - Have them because they are hard and protect the ends of structures - Nail Parts a) Nail body: o Part that can be seen of the nail b) Free edge: o Distal portion of the nail o Part that gets clipped back when nails are trimmed c) Lanula: o Proximal end of the nail body o Generally, the white part at the base of the free edge d) Nail fold: o Skin that surrounds the nail o Have lateral, proximal, medial nail folds, etc. e) Nail bed: o Skin that is underneath the nail f) Nail matrix: o Where the fingernails grow from o Part of the skin under the proximal end o Undergoes cell division and pushes everything forward g) Eponychium: o Flesh, skin, and tissue that covers the nail matrix h) Hyponychium: o If pull backs on the tips of the fingernails at the free edge, the hyponychium is the attachment point under the free edge Hair: - Epidermal appendage - Scale-like appendage - Functions of hair: o Nerve endings at the base of the hair allow humans to sense when insects are growing on the body o Acts as a cushion and protection form physical trauma o Insulator Prevents heat loss o Works as a filter Protects against UV radiation that could cause cancerous skin production - Located in the nose and eyes and places that filter things around us - Hair structure: a) Shaft: o Above the surface of the skin where it can be seen o Shaft Layers: 1. Medulla: Middle portion Surrounded by the cortex Each dark circle represents an accumulation of pigment Melanin also causes humans to have dark colored hair Theomelanin causes red and blond hair 2. Cortex: Surrounds the medulla 3. Cuticle: Outer layer of dead stacked cells Needs to be kept moist so they won’t get bristly b) Root: o Part of the hair that can’t be seen o Located under the skin c) Follicle: o Skin part (Tissue) that surrounds the root o Mostly in the epidermal region but there is epidermal inward growth into the dermis that produces the hair o Structure of hair follicle: 1. External root sheath: Made up of connective tissue Means it is part of the dermis 2. Internal root sheath: Part that immediately surrounds the hair follicle In the epidermis Hair growth occurs from the internal root sheath that produces a matrix that makes up the middle of the hair and is the growing part Every other part is made from this 3. Bulb: As you follow down the hair follicle, it enlarges at the base known as the bulb in the dermis Root endings surround the bulb that are sensory receptors that make a root nerve plexus Functions in light touch sensitivity due to crawling bugs 4. Papilla: Indention in the bulb Located in the dermis 5. Arrector pili: Involuntary smooth muscle located at the base of each hair When cold, the arrector pili muscle contracts and pulls on the base of the hair follicle to cause it to stand up When the hair stands up, it functions in helping the body to lose less heat at the surface of the skin Also respond to excitement stimuli Slide 28: Functions of the Integument Protection: - Possesses mechanical, chemical, and biological protection Regulation of body temperature: - The skin itself contains sweat glands that cool down the body - Hair keeps the body warm Sensations: - 2 sensory components: a) Merkel’s discs Bottom between the epidermis and dermis b) Root hair plexus Surrounds the bulb Metabolic functions: - Skin will produce an inactive form of Vitamin D due to the exposure to sunlight - Vitamin D is necessary for calcium absorption and is important in normal immune function Maintains blood reservoir: - Capillaries in the skin and dermis allow the body to have extra blood - Ex: When working out, the blood vessels can be constricted to pump more blood to the heart Excretion: - Can get rid of nitrogenous wastes predominantly by the breakdown of proteins Excreted via sweat Slides 29-31: Tactile Sensors Merkel’s discs: Light touch - Sensory receptor located very deep in the stratum spinosum of the epidermis and are basically at the epidermis-dermis border - Epidermal receptor that responds to light touch Meissner’s corpuscles: Light touch - Located just on the other side of the border of the dermal side - Where the dermal papillae are located - Sensitive nerve endings that are activated by the stimuli of light touch Pacinian corpuscles: - Located deep in the dermis - Responds to deep pressure - Adapts very rapidly Continual exposure to a pressure stimulus leads to the shutting off of the signal that is being sent Root hair plexus: - Surrounds the base of the hair follicle - Responds to hair being moved Slides 32/33: Burn Brennen is German for “to consume by fire” Tissue damage caused by intense heat, electricity, radiation, or chemicals that results in protein denaturation - Collagen and elastin proteins, etc. can all be denatured If the burn is strong enough, it will lead to the death of cells Largest concern is dehydration and loss of electrolytes - The cutaneous membrane is a barrier Part of the barrier is to prevent water loss If part of the barrier is lost, fluid loss will occur along with electrolyte imbalance Decrease in urinary output due to kidney failure Burns can also lead to systemic consequences where a bacterial infection can result since the outer layer has been breached This is secondary to water loss Burns and ultimately destroy blood vessels in the dermis and underlying tissues This reduces blood flow and the dermis functions as a blood reserve Slides 34-36: Burn Classifications First-degree: - Any burn that results in redness, swelling, and pain - Only a partial thickness burn Only the superficial layer of the skin is burned - Pain will be experienced due to pain receptors of the skin that are activated and send lots of signals - Superficial layer will heal on its own without intervention in 2-3 days Refers to heat, steam, chemicals, etc. - Ex: Sunburn Second-degree: - Redness, swelling, pain + blisters - Still considered to be a partial thickness burn - Epidermis and parts of the dermis are burned but with most of the dermis still in tact - Heals on its own without intervention in 3-4weeks Third-degree: - Full thickness burns - Skin is charred - Skin has lost its entire function because it is completely damaged - Doesn’t have pain because of the sensory receptors in the skin are destroyed But edges have first and second-degree burns that still have pain receptors present - Will not heal on its own since the tissue is completely destroyed Must have tissue graft where skin is taken from another part of the body and it is grafted across so it grows there Slides 37-44: Skin Disorders Acne: - Androgens stimulate the sebaceous glands to produce oil (Sebum) that bacteria feeds on o Acne in most boys is due to oil production triggered by testosterone - AKA: Bacterial infection of the sebaceous glands - This is specifically a staphylococcus aureus infection Use antibiotics - MRSA is antibiotic resistant and is a concern Lupus: - Autoimmune disease of the skin where the body attacks part of its own body - Lupus is Latin for “Wolf” Often times the skin looks like a wolf bit someone - Main symptom is the butterfly rash that appears across the bridge of the nose and under the cheeks - Not contagious - Mostly occurs in post-pubescent females Psoriasis: - Itchy, scaly skin that is red - Possibly is an autoimmune disease - There are many triggers for psoriasis such as trauma to the skin Triggers the immune system o Other triggers could be infection, hormonal changes, and stress - Phototherapy is used—Person is put in sunlight - Can be genetic - Steroid treatment with Medrol dosepacks Steroid drugs that shut off the immune system so that it doesn’t have a way to attack the skin Decubitus ulcers: - Bedsores - Result of contact - Common in immobilized patients - Open sores that are due to a constant deficiency of blood Due to the pressure of sitting in the same spot Tissue becomes necrotic and gangrenous Rotting - Smells - Can also happen when a cast is applied to a broken bone that is too tight Vitiligo: - Pigmentation disorder that is the most common - Parts of the skin have an absence of melanocytes so melanin isn’t produced + there can be a patchy distribution of the absence of the melanocytes - Cause is probably due to an autoimmune disease where the body attacks the melanocytes in certain areas of the body - Appears as if a person has been burned and is healing - Can be born with the absence of pigments or can develop over time (Why it is thought to be an autoimmune disease since it manifests itself) Albinism: - Complete absence of pigmentation - Inherited genetic condition - Melanin can’t be produced due to the prevention of the production of tyrosinase where tyrosine can’t be converted to melanin - A person appears vey white but also pink due to the hemoglobin being the only pigment in the skin - Amount of pink changes are dependent on ambient temperature: o Dilation Pinker skin o Constriction Grossly white - Eyebrows, the iris of the eye, and eyelashes have no color Freckles: - Patchy distributions of melanin due to extra melanocytes - Seems to be linked to fair-skinned individuals - Often linked to red-heads and certain ethnicities—Think there is a genetic component to this Birthmarks: - Not sure what causes these - Baby is born with this pigmentation such as strawberry spots - Get a dense collection of dermal blood vessels in a certain portion of the body Strawberry colored pigmentation as a result Bone Slide 2: Skeletal Tissue Bone is composed primarily of bone and cartilage Skeleton starts out as cartilage Changes to bone via an ossification process Not all skeleton starts as cartilage though Some skeleton starts as fibrous connective tissue that then ossifies Humans are born without all of our bones (Ex: Knee caps) - Humans grow from the point of birth to at least adolescence As a result, bones have to change and reform Slide 4: Skeletal Cartilages Perichondrium: - Layer of dense irregular connective tissue that surrounds the outer part of cartilage - AKA: Outer covering of the cartilage - All cartilage has a layer of dense irregular connective tissue covering it - Cartilage is hard to heal since cartilage does not have blood vessels or nerves—Takes a long time to heal due to lack of circulation going to cartilage tissue - Perichondrium is therefore significant in the fact that it contains the blood supply and nerves necessary to supply the cartilage it surrounds Skeletal cartilages include: - Hyaline cartilage - Elastic cartilage - Fibrocartilage Slide 5: Hyaline Cartilage Most abundant cartilage Articulation: - When have 2 bones that come together - The ends of bones at an articulation are covered with hyaline cartilage - Means that hyaline cartilage is categorized as articular cartilage since it is at the ends of bones at joints Hyaline cartilage makes up: - Intercostal cartilage - Rings of cartilage in the trachea - Form the larynx - Nasal cartilage (External nose) Slide 6: Elastic Cartilage Elastic cartilage makes up: - External ear (Pinna) - Epiglottis: Flap that covers the trachea/windpipe when one swallows so food doesn’t go down into the respiratory tract Slide 7: Fibrocartilage Extra pads of cartilage called menisci Fibrocartilage is located between vertebra Found in areas where a lot of crushing force is experienced Slide 8: Growth of Cartilage Cartilage grows to produce more cartilage Sometimes the growth of cartilage ends up producing bone via calcification: - Deposition of calcium salts is important in the conversion from cartilage to bone Cartilage is able to grow: a) Appositionally: - Grows from the edges where the perichondrium cells secrete new matrix at the interstitial junction that expands the cartilage Chondrocytes develop b) Interstitially: - Instead of cartilage growing from the perichondrium, it grows due to the division of the chondrocytes inside the lacunae in the cartilage tissue Chondrocytes secrete the new cartilage matrix - Mastering HA&P: Interstitial growth occurs when chondrocytes divide and form new matrix, thereby expanding the cartilage tissue from within. This causes the cartilage to lengthen. All growth of cartilage stops at adolescence (Typically speaking Are able to get some repair of cartilage) Elderly tend to have larger ears and noses since some of the cartilage doesn’t stop growing Slide 9: SkeletonDivisions Axial Skeleton: - Roles are for support and protection - Consists of the skull, vertebrae, and ribs o Can see the rib cage that protects organs in the thoracic cavity Appendicular Skeleton: - Functions in local motion (Movement - Consists of all the bones of the upper and lower limbs attached to the axial skeleton + pectoral girdle of the should blades and collar bones + pelvic girdle Slide 11: Bone Classifications- Long Bones Bone is classified based on shape and texture Bones that are longer than they are wide All of the bones of our upper and lower limbs are classified as long bones - Ex: Humerus, femur, fibula, etc. - Exceptions: o Patella (Knee cap) o Bones that make up the wrist (Carpals) and ankles *Bones of fingers (Metacarpals and phalanges)/toes and hands/feet are long bones though Slides 12-14: Long Bone Structure Diaphysis: - Individual bones are consisted of 2 ends a middle region - The shaft part in the middle region is the diaphysis - Bones can be classified based on bone texture o The diaphysis of the shaft contains several layers of compact bone (Dense, tightly joined bone cells) that cover a layer of spongy bone o Furthermore, compact bone making up the diaphysis surrounds spongy bone that has a hollow central cavity called the medul
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