A&P Exam 1 (1).pdf

Chapter 1 - The Human Body Anatomy vs Physiology Anatomy - the various structures of the body and their relationship to one another, what does it attach to? - Gross anatomy: the structures visible to the naked eye, describe physical shape and relationship - Regional vs. syste...

Chapter 1 - The Human Body Anatomy vs Physiology Anatomy - the various structures of the body and their relationship to one another, what does it attach to? - Gross anatomy: the structures visible to the naked eye, describe physical shape and relationship - Regional vs. systematic anatomy - Microscopic anatomy: structures that are microscopic Physiology: how these individual body parts work (or function) on a normal level - Cytology - study of cell - Most often considered at the cellular/molecular level Principle of Complementarity of Structure and Function - What structures can do is dependent on its form - Ex: the stomach is responsible for breaking down food, 3 layers of muscle that break down food to make it easier - Changing structure can change function Structural Organization of the Human Body - Chemical level (basic level) - Atoms combine to form molecules - Cellular Level - The smallest unit of life because they can carry out functions - Grow, reproduce, respond to hormone/stimuli - Different types of cells do different things - Tissue Level - Aggregations (cluster) of living cells that carry out similar function (not every cell is the same in that aggregation but carry out similar functions) - Four basic types: muscle, epithelial, nervous, and connective - Organ Level - Two (or more) tissues operate together to perform a certain function - What is the difference between a tissue and an organ - Organs are more complex in their function, tend to be more specific - Organ system level - Multiple organs work together to accomplish a purpose (chain) - What is the difference between an organ and an organ system? - More complex, can carry out a greater number of functions - Organismal Level - All organ systems work together to keep the organism alive - Respiratory system helps organisms breathe, if the respiratory system doesn’t work, organism will die Necessary Life Functions - Maintaining boundaries - At the cellular level and at the organismal level  - At the cellular level, the plasma membrane, is an example of maintaining boundaries, it regulates what enters and leaves the cell - At the organismal level, the integumentary system (skin) serve as the body’s outer layer preventing things like pathogens and toxins from damaging internal organs - Movement - must occur for life - Cooperation of skeletal and muscular systems to coordinate actions - Can be conscious movements, or not - Skeletal muscles (voluntary) - When you decide to chew - Smooth muscle (involuntary) - Walls of hollow organs - Digestive system, urinary - Cardiac muscle tissue (involuntary) - No control of when these muscles contract, saves brain energy - Responsiveness - Sensing environmental changes and responding to them both external/internal - The nervous system is primarily involved with excitability, particularly through the neurons - Neurons can detect changes (stimuli) and send electrical signals (impulses) throughout the body to trigger an appropriate response - Ex: touching a hot stove - Sensory neurons send rapid signals to the CNS where the brain processes and sends them back via motor neurons - Signals can also reach muscle tissue allowing hand to pull away from the heat - Digestion - Food is broken down into simple molecules to be absorbed to blood and delivered to various tissues - Metabolism - The sum of all chemical reactions in the body that takes place in the cell - Catabolism (taking large molecules and breaking down into individual amino acids) - Anabolism - building larger molecules from smaller ones - Cellular respirations (all chemical reactions used to produce ATP - What is an example of this life function? - Electron transport chain (produces >50% ATP) - Excretion - Removal of waste produced during digestive and metabolic functions - Kill cell, interfere with cellular functions - Carbon dioxide is a waste product - Nitrogenous waste: ammonia through the urinary system  - Growth - Increase in the number of body cells, or increase in size of individual cells themselves - Building must occur faster than breakdown in the body - Anabolic reactions must be more than catabolic reactions Survival need in order to carry out life functions - Nutrients - Brought into the body by ingestion - Include carbohydrates, fats, and proteins along with vitamins and minerals - Macronutrients - Carbs, fats, proteins - Micronutrients - Vitamins (used in chemical fractions) and minerals (structurally important used to build things) - Oxygen - Cells can only survive a few minutes without oxygen - Will run out of ATP, and die - Water - Provides an environment for chemical reactions and serves as a fluid base for secretions and excretion - Primary solvent, used for various chemical reactions - Produces digestive fluids (>50%) - Endothermy - Generates body heat - Body temperature must be maintained for chemical processes to occur - Speeding up chemical reactions - Excretion: waste disposal - Secretion: process in which body cell removes something they produced - Salivary gland produces saliva - Atmospheric Pressure - Breathing and gas exchange occur at an appropriate atmospheric pressure altitude sickness Homeostasis - Maintenance of the internal condition of the body despite a constantly changing external environment - This maintenance is not a static state (not completely unchanging) - Accomplished by the work of all virtually all organ systems - Mostly concerned with central nervous system (brain sends signals) and endocrine system (series of organs scattered throughout body that produce and release hormones) - Chemical signals that causes change in body - Control of homeostasis - Variable: what organ or function is being controlled or regulated - Three parts (or mechanisms) involved in variable control/regulation - 1) Receptor - cell type that receives information about variable  - Thermal regulation in body temperature, receptor will send information to the control center - 2) Control center (brain/spinal cord) - receive message and figures out what message means and sends out a response message - 3) Effector - part of the body that carries out the response - Body temperature is too low, and needs to be increased, sends a message to skeletal muscle (effector) and the body will shiver - Too warm, sweat glands become effector - **Effector changes based on the brain** - Homeostasis is controlled by negative feedback mechanisms or positive feedback mechanisms - Negative feedback mechanisms: cause the variable to change in a direction that is opposite of the initial change - **good for making changes around our optimal** - Ex: thermoregulation, most hormones - - The optimal temperature environment is 98.6 degrees - Positive feedback mechanism: causes the original change of the variable to be enhanced (i.e accelerates the change) - Different from the negative feedback mechanism because we want to produce a very large change, want the variable to be enhanced - Explosion - variable increased - Blocking - variable decreased - Do not control events that require frequent small adjustments, not constant like a negative feedback mechanism - Prevalent in emergency situations - Ex: labor and blood clotting - Negative feedback mechanism is used more often in the body - Imbalances in homeostasis - Aging leads to homeostatic imbalance - Control systems become less efficient, making us more susceptible to disease  - Cascade of events caused by positive feedback mechanisms can overpower negative feedback mechanisms - Ex: autoimmune disorder, immune system destroys own body cells - Imbalance in homeostasis leads to all known diseases/sickness Anatomical Terms - Reference point: anatomical position - Directional terms: help us explain one body part in relation to the others - Dorsal (posterior)- back side vs. ventral (anterior) – belly side - Lateral (far from midline) vs. medial (mid line) - Distal vs. proximal – relative to point of origin - Deep vs. superficial – relative to surface of body - Superior vs. inferior – top vs bottom - Head is superior to neck - Body Planes - Sagittal: divides body into left and right - median/midsagittal plane divides the body exactly in half - Frontal: divides body into anterior and posterior - Transverse: divides body into superior and inferior part - Body Cavities - Most organs are found in one of the body cavities - Dorsal body cavity: protects organs of the central nervous system (CNS) - Composed of the cranial cavity (empty space in the brain) and spinal cavity (space created by vertical column) - Ventral body cavity: found on front side, houses visceral organs - Composed of: divided by diaphragm - Thoracic cavity: contains heart and lungs - Chest cavity - Abdominopelvic cavity: separated from thoracic cavity by diaphragm - Membranes of the Ventral Body Cavity - Serous membrane (serosa): double-layered membrane that surrounds all organs preventing them from rubbing against each other - Visceral serosa: innermost layer covering the organ - Parietal serosa: outer layer lining the body wall of the cavity - These layers are separated by a small amount of serous fluid - Oily texture, important because we don’t want these layers to touch - Serous membranes are named according to their location - 1) Pericardium: serous membranes surrounding the heart, allows for separation of the chamber - 2) Pleura: serous membrane surrounding the lungs - 3) Peritoneum: serous membranes surrounding most organs of the abdominopelvic cavity - **Esophagus and kidneys don’t have serosa** Chapter 2 - Chemistry Mixtures: any substance containing two or more components physically intermixed - Types of mixtures - body fluids, can come in solids and gases - 1) Solutions: homogeneous mixtures that can exist as a solid, liquid, or gas composed of very small particles that do not settle out - Solvent is the dissolving medium - Water is the body’s primary solvent - Solute is dissolved in a solvent, does not settle out of solution, remains suspended, evenly distributed throughout solvent - Ex: saline solution (water + NaCl) - Concentration of a solution can be described using: - A) Percent Solution: amount of solute dissolved is expressed as a percentage of the total solution volume - B) Molarity (mol/L): the number of moles of a substance per liter of solution - **a mole of any element or compound is equal to its molecular weight - 2) Colloids: heterogeneous mixtures composed of large solute particles that do not settle out - Can undergo sol-gel transformation → mixture can change from a fluid state to more solid state (and back again!) depending on what's needed by colloids - Ex: cytosol of cells changes consistency depending on certain cell activities (cellular division, change in shape, etc.) - 3) Suspensions: heterogeneous mixture composed of large solute particles that do settle out of solution, tend to be larger particles compared to colloids - Ex: Blood contains a fluid portion (called plasma) with various cell types (red blood cells, white blood cells, & platelets) suspended in it Chemical Reactions - Occur when chemical bonds are formed, broken, or rearranged - Chemical bonds are stored energy, energy is released when these bonds are formed, broken, or rearranged - Types of reactions: - 1) Synthesis reaction: formation of bonds between atoms or molecules to form larger, more complex structures - Are endergonic - contains more energy after formation - Ex: anabolic reactions in the body - 2) Decomposition reactions: bonds are broken to create smaller molecules or individual atoms - Can be endergonic but are (mostly) exergonic - release energy when bond is broken (spontaneity of energy) - Ex: catabolic reactions in the body Inorganic Compounds & Their Role in Homeostasis - Water: makes up most of the total body mass and most of the volume of individual cells - Importance in homeostasis - A) Universal solvent  - Transport → water carries nutrients, respiratory gasses, metabolic waste, etc - Water can surround some charge structures to prevent interactions with other charged particles - B) High heat capacity - the amount of heat that a substance needs to absorb in order to raise its own temperature by 1 degree Celsius - Water has the highest heat capacity - Can absorb a large amount of heat with little change to its own temperature (important for homeostasis) - C) Protection - water-based fluids provide a “cushion” for internal organs - D) Heat of vaporization is high - the amount of heat that water needs to absorb to break the bonds and vaporize - Large amount of heat must be absorbed to break bonds & cause evaporation - Important to homeostasis because when our internal body temperature increases we produce and release sweat, surface sweat absorbs heat and vaporizes so it releases heat - E) Reactive - Water is used in several chemical reactions in the body - Hydrolysis reaction (breaking bond with water) AB + H20 → A-H +B-OH vs. dehydration synthesis (removing water to build) AB +H20 ← A-H +B-OH - Cannot breakdown carbohydrates that we consume without water - Salts: dissociate in solution to form electrolytes - Importance: electrolytes Na+ and K+ allow for muscle contraction and transmission of nerve impulses, Fe+ found in red blood cells used to carry O2 - Acids & Bases: also form electrolytes, influences pH, especially blood pH - Acids: releases H+ ions in solution - Causes pH to drop - Bases: release OH- ions in solution - Causes pH to increase - The optimal blood pH is 7.2-7.4 - Alkalosis - when blood pH is above 7.45 - Acidosis - when blood pH is below 7.35 - Problem: high/low pH disrupts cellular activity, hydrogen bonds, etc - Solution? Buffers! - Strong acids: completely dissociate in water, they release all their hydrogen ions (H+) into the solution - Weak acids: partially dissociate, they only release some hydrogen ions - Occurs when blood pH becomes too basic, releasing more H+ will help lower the pH - Weak bases - tie up excess H+ when pH becomes too acidic  - Used when blood pH becomes too basic, will tie up excess H+, helps increase pH - Result: buffers prevent large changes in pH that could cause excessive damage to the body Organic Compounds & Homeostasis - All organic molecules found in the body contain carbon - WHY? - It is electroneutral → it neither gains nor loses electrons, shares them equally - Can form molecules of various shapes (long chains, rings, etc) that all have specific functions in the body - Long strands of carbon - help build fiber in connective tissue - Ring-like structures - DNA - Macromolecules: polymers that are made up of several small, identical subunits called monomers - 1) Carbohydrates: sugars and starches - Monomer: monosaccharide - Monosaccharides: glucose**, fructose, galactose - Glucose is used to produce ATP - Monosaccharides can form disaccharides, polysaccharides - Monosaccharides can be used directly by the body but not for energy production - Only glucose can be used for ATP production - Polysaccharides are important for cell-to-cell interactions - Sitting on body cells surface - used to help with identification - Major functions: - Fast, easy-to-use energy source - Cell-cell interactions → Carbohydrates attached to the cell surface, used to communicate - 2) Lipids - 3 types of lipids - A) Triglycerides - stored in adipose tissue - Monomer: fatty acids and glycerol - Varieties of triglycerides: - Saturated → contain only single covalent bonds, molecules packed closely together - Fat found in meat products (tend to be solid at room temp) - Unsaturated → contain 1 or more double covalent bonds, molecules more spread out - Ex: most plant-based oils, avocados - Trans fat → oil fats that have an H added at sites of double bonds, also tend to be sold at room temperature - Ex: donuts, cookies → the worst for you  - Omega-3 fatty acids → oil fat found in cold water fish (healthiest) - Ex: salmon, krill oil, fish oil capsules - **Major Functions: protection, insulation, fast & easily accessible energy storage - Tend to be subcutaneous, sits under the skin - B) Phospholipids - Modified triglycerides with fatty acid chains and phosphate group - Fatty acid chains are hydrophobic - don’t like water - Phosphate “head” is hydrophilic - **Major function: used to build cell membranes (phospholipid bilayer) - C) Steroids - Most important steroid for life is cholesterol - Ingested in eggs, meat, cheese - Liver produces cholesterol (85% of the body’s requirement) - ** Major functions: structural component of cell membranes, is “base” used by body to form other steroids (steroid hormones - testosterone & estrogens, corticosteroids) - help plasma membrane from breaking/tearing easily - 3) Proteins - Monomer: amino acids - Specific amino acid sequence leads to a variety of protein functions - Individualized form and function - Structure determines function! - A) Fibrous protein → forms long strands that can link together to form long, stable structures - functions(s): provides mechanical support & tensile strength, some contractile ability - Can return to original length after being stretched - Ex: collagen (main), muscle - B) Globular proteins → compact, spherical in shape - Chemically active - Function(s): transport molecules, immune defenses, regulation of growth & development - C) Enzymes: biological catalysts - Function: catalyst lower the activation energy of chemical reactions - Vary degrees of specificity - Some only catalyze 1 reaction, others can catalyze multiple reactions - Importance: without enzyme, most reactions in the body would either not occur or would occur too slowly to sustain life - ATP & cellular energy  - Adenosine triphosphate (ATP) is *the* energy transferring molecule of any body cell - OXYGEN is required to produce ATP - ATP has a triphosphate tail that has high bond energy - a little unstable - When a phosphate tail is transferred to another molecule, that molecule temporarily has more energy to do work - While doing work, the molecule loses the phosphate group - ATP storage & release is similar to energy needed to drive most chemical reactions - What does this mean? - Very little ATP storage, cell only produces as much ATP as they need in the moment - ATP sitting around doing nothing = wasted energy - ATP is required to produce ATP - **without ATP, chemical reactions stop, cell transport stops, muscle cannot contract → death occurs** Chapter 3 - Cells, Plasma Membrane The Cell - Prefix: “cyto-” (ex: cytoplasm) - Suffix: “-ctye” (ex: osteocyte) indicates a specific cell type - The cell is the smallest living unit of life - Different types of cells have different functions in the body - What allows cells to have different functions? - ATP is needed for cell function, microscopic anatomy results in different functions, different organelles = different specialized functions - Loss of homeostasis in cells often leads to disease - Result of different cells losing function - Despite the differences in function, every cell has 3 basic parts - 1) Plasma membrane: outermost boundary, selectively permeable, allow things to pass from its external environment, others will not be able to pass - 2) Cytoplasm: intracellular fluid - Mostly water, but also contains salts and organic molecules - 3) Nucleus: controls cellular activities, contains all genetic information, codes for certain proteins to be produced - **not all our body cells have a nucleus - Ex: red blood cells, etc. bc they have short lifespan Plasma Membrane - Fluid Mosaic Model describes the general structure of the plasma membrane - Plasma membranes consist of a phospholipid bilayer with proteins randomly dispersed in it - Largely impereable to water soluble molecules  - **separates the intracellular fluid (ICF) - inside cell from the extracellular fluid (ECF) - outside the cell Chemical Composition of Cell Membranes - 1) Lipids - A) Phospholipids: forms basic structure of membrane - Polar Phosphate head: hydrophilic portions contact intracellular or extracellular fluid - Nonpolar Fatty acid tails (2): hydrophobic portions that face inwards which prevents polar molecules from easily passing through - **aggregation of hydrophobic and hydrophilic regions leads to ability of cells to reseal when damaged/torn - B) Cholesterol: provide structural support to “stiffen” the membrane, still flexible but not as easily damaged → increase membrane stability - 2) Proteins - Constitute most of the cells specialized membrane functions - 2 types of membrane proteins by location: - A) Integral proteins: embedded in the plasma membrane - Transmembrane proteins span the entire width of the membrane - **Major functions: transport, carriers enzymes, receptors, cell-cell recognition, etc - B) Peripheral proteins: loosely attached to integral proteins - Are not found *in* the lipid bilayer - Major functions: enzymes, motor proteins, cell-cell attachment - - 6 types of proteins by function: - A) Transport proteins: move substances in and/or out of cells, and around inside of cell - Carrier proteins and motor proteins - Different structures, move proteins differently - Some proteins form channels through which a particular solute can be selectively moved  - Other proteins activity pump substances across the membrane surface by using ATP - Ex: sodium-potassium ATPase pump - Must have conformation change for transport to occur - B) Receptor proteins: can relay messages to cell interior when protein is bound to/exposed to certain chemical messengers - Ex: hormone - Specificity to chemical messengers can vary, some can only bind to one specific messenger, others will need to bind to multiple simultaneously - When bound to specific chemical messengers → protein changes shape, leading to series of changes inside the cell - Ex: receptor protein binds to hormone → cellular activity changes - C) Enzymes: proteins that catalyze chemical reactions - Some enzymes act alone, others may act as a “team” to catalyze sequential steps - Lower chemical energy needed for reactions to occur - D) Cell-cell recognition proteins: allow body cells to recognize other body cells - Immune system, we all create our own glycoproteins, since we're all individuals - It allows us to tell our own body cells from nonbody cells - E) Attachment proteins: help hold some membrane proteins in place, maintains cell shape - Can be located inside of the cell or outside, depending on function - Holding from outside of cell helps maintain cell shape - F) Intercellular junctions: some proteins are used to link cells together - Length of time to link cells varies - Major function: assists with cell migration - 3) Carbohydrates - Extracellular surface is dotted with short-branching carbohydrates - Can be attached to membrane lipids (glycolipids) or proteins (glycoproteins) - Glycolipids and glycoproteins create the glycocalyx - Different cell types have different arrangements → allows for identification of cell types by other body cells - Can also identify one tissue from another tissue - Can think of as sugar-coating - Can also contribute to structure/shape of cell membrane (minor extent), allows plasma membrane to be less fluid in nature Junctions - Cell junctions: a class of proteins that provide contact or adhesion between two or more cells  - Can be permanent or temporary - Types of junctions: - 1) Tight junction: proteins in cell membranes of neighboring cells fuse together. Tend to be permanent - Junction is impermeable → nothing passes - Ex: tight junctions between epithelial cells of the stomach prevent gastric juices from “leaking out” - Inner lining of stomach secrete hydrochloric acid, must keep material where it is - 2) Desmosomes: anchoring junctions from one cell to another that prevents separation - Cellular velcro - Found in places that stretch - Ex: skin - Function: bind cells together to form sheets that resist shearing forces when pulled/stretched - Components of a desmosome: - Cadherins: protein filaments extend from the cell surface and link to filaments on other cell surfaces - Inside the cell, a plaque holds the cadherins in place - Keratin filaments hold a plaque in place to prevent excessive movement/shifting - If any of these things didn’t exist, everything would start moving - 3) Gap Junctions: “communication” junctions - Intercellular channels between two cells - Channels line up with each other that creates a gap junction - Allows cells to pass material on to each other - **Big function → ion exchange - Hollow cylinders (formed by proteins) connect adjacent cells - Different proteins used to create gap junctions/substances through channels - Membrane Transport: Passive - Definition: movement of molecules across the membrane down their concentration gradient (diffusion) with no ATP required - High to low concentration → diffusion - Driving force of diffusion: kinetic energy of molecules - In areas of high molecule concentration → molecules collide and bounce off one another more frequently - Faster rate of collision = faster diffusion - Diffusion speed determined by 3 factors: - 1) Concentration: greater concentration difference between two areas leads to faster diffusion  - Water molecules will move to areas of higher concentration to reach equilibrium - 2) Molecular size: smaller molecules diffuse faster - Larger molecules travel slower - 3) Temperature: higher temperatures results in faster diffusion rates - Higher temperature = higher kinetic energy, increase collision, speeds up diffusion - Types of Diffusion (Passive Transport) - 1) Simple Diffusion: diffusion of a substance directly through the lipid bilayer - Does not require a protein to get through membrane - **Most molecules diffusing are small in size & non-polar - Small molecules can squeeze between lipids, also tend to be lipid soluble and non polar - Water soluble molecules can just pass through because fatty acid tails are hydrophobic - Ex: most gasses, steroid hormones, fatty acids, etc. - 2) Facilitated diffusion: diffusion of molecules through the membrane with the use of a protein - Types of facilitated diffusion - A) Carrier-mediated: transmembrane proteins used to carry large molecules through the membrane - Protein changes shape while moving substance - Limits: the cell can only move substances as fast as proteins become available to move them - Some carrier proteins can carry more substances - Channel-mediated: transmembrane proteins form water-filled channels through which molecules can pass - Selective → size of channel determines what substance can/cannot pass through - Good for water-soluble proteins, ions, and some larger size - Some will sort molecules by charge - Proteins can form leaky or gated channels - What is meant by “leaky” and “gated”? - Leaky - not being able to close off channel, protein is transported consistently - Gated - can open or close, can stop movement if needed - 3) Osmosis: diffusion of water through a selectively permeable membrane - Water loves to follow solute, will move from low solute concentration to high solute concentration until a side a balanced - Can occur without proteins or with the use of aquaporin proteins - Specific to moving water, does not require energy - Osmolarity: the total concentration of all solute particles in a solution - A solution with a high osmolarity will have a greater number of solute particles than a solution with a low osmolarity - Can cause water to move based on where the solute is - Water moves by osmosis until hydrostatic pressure (the pressure of water pushing on the inner cell wall) is equal to the osmotic pressure (tendency of water to move into a cell by osmosis) - Osmosis will determine how much water is in the cell - When the two pressures are equal → no net movement of water is observed - If one water molecule moves in the cell, one must leave - Our bodies have semipermeable membranes - Water is allowed to cross but solutes cannot - Water will move to the higher concentrated area to reach equilibrium which will cause a volume change - We DO NOT want this happening to our body cells - Imbalances in osmosis cause body cells to swell or shrink depending on total water volume inside cell - Tonicity: the ability of a solution to change the shape of a cell by altering the cell's internal water volume - Water will follow solutes → A change in solute concentration on either side of a membrane will also cause a change in water concentration - **Tonicity always refers to the solution that a cell is submerged in!** - The effect of solutions of varying tonicities on cell size/shape - 1) Isotonic solutions have the same concentration of nonpenetrating solutes as those found inside the cell - No net loss or gain of water observed - Nothing will change in cell size/shape  - 0.9% NaCl solutions, extracellular fluid - Anything above 0.9 is hypertonic - 2) Hypertonic solutions have a higher concentration of solutes than inside the cell - Water moves out of the cell because the concentration outside of the cell is higher - Cell will “shrivel up” or crenate - Ex: 10% NaCl solution - 3) Hypotonic have a lower concentration of solutes than inside the cell - Water moves into the cell because higher concentration is now inside the cell - Cell will “swell up” until they burst (lyse) - Ex: distilled water - No solute in it - Active forms of Membrane Transport - Movement of molecules across the plasma membrane that requires energy input (use of ATP) - Used when molecules are too big, too changed, insoluble in lipid membrane, or moving against their concentration gradient (low to high concentration) - Active transport requires → transport proteins - Types of active transport - 1) Active transport - Use of a transmembrane protein and ATP to move molecules across the plasma membrane against their concentration gradient - 1) Primary active transport: energy required to do work comes directly from ATP hydrolysis by transport proteins called pumps - Phosphorylation of pump leads to a change in protein shape → allows protein to move molecule across the membrane - Sodium - Potassium pump - Uses enzyme Na+ - K+ ATPase enzyme - Pumps Na+ and K+ against their concentration gradient in opposite directions across the membrane - For each ATP molecule, ATPase moves 3 Na+ ions and 2 K+ ions - Sodium (Na+) is pumped out of the cell - Potassium (K+) is pumped into the cell - This helps create that responsiveness of cells like muscle and nervous cells - Phosphate tail of ATP provides energy needed  - **ATPase pumps must maintain electrochemical gradient necessary for function of muscle and nervous cells** - 2) Secondary active transport: indirectly uses energy stored in electrochemical concentration gradients of ions created by primary active transport - Ex: moving Na+ out of cell creates a concentration gradient - Cotransport protein pumps Na+ back into the cell and carries another molecule (glucose with it) - **we don't have phosphate tail directly attached - Molecule that moves against concentration gradient is called the driven molecule - Active transport system: Number of Solutes Moved and Direction of Solute Movement - 1) Symporter: movement of two transported substances in the same direction - 2) Antiporter: movement of two transported substances in the opposite direction - 3) Uniporter: movement of one substance - 2) Vesicular transport: movement of fluids with large particles & macromolecules inside membranous sacs called vesicles made of plasma membrane - Funticions - 1) Endocytosis - movement of a substance into the cell from ECF - 1) Phagocytosis: cells engulfs large and/or solid material - Forms a vesicle called a phagosome - Pseudopod formation involves receptors → formation is specific - Phagosome usually fuses with lysosome (produces digestive enzymes), where contents are digested - 2) Pinocytosis: cell brings in a small volume of extracellular fluid containing small solute particles. They are sampling their environment so they know what’s going on around them - Cell membrane is forming small vesicles - No receptor use needed → not a specific process - **know when ions are balanced, warning messages can also be brought in by neighboring cells - 3) Receptor-mediated endocytosis: allow endocytosis of specific substances to occur  - Extracellular substances bind specific receptor proteins - **Substances can be specifically concentrated in vesicles & brought into cell - Are smaller so that can be brought in at a faster rate - A) Contents can be distributed through the cell - B) Vesicle can fuse with lysosome for digestion of concentrated substance - 2) Exocytosis - movement of substance out of the cell - Secretory vesicles created around the substance to be removed - Travels to plasma membrane, fuses with it, and dumps contents out of the cell - Balances endocytosis because you are continually taking away from the plasma membrane, fusing allows the plasma membrane to be regenerated - Functions: hormone secretion, neurotransmitter release, mucus secretion, waste removal, etc - 3) Transcytosis - movement of substance into, across, then out of a cell, allows for passage through tissues - 4) Vesicular trafficking - movement of a substance from one area of the cell to another, nothing ever leaving - Membrane Potential - Selective permeability of plasma membrane regenerates a membrane potential (voltage) across the membrane - Voltage → electrical potential energy resulting from separation of oppositely charged particles (ions) - All cells have a resting membrane potential → voltage difference across membrane when cell is at rest - Average of -70 mV - All cells are electrically polarized because cells have different charges inside/outside - Negatively charged inside - Positively charged outside - Creation of membrane potential involves an ion imbalance on either side of the plasma membrane - Sodium does not play a role in creating or maintaining a cells resting membrane potential, only charges it - Ion concentrations of Na+ is higher outside the cell and K+ is higher inside the cell - Potasssion ion (K+) are important in creating the resting membrane potential  - Plasma membrane are more permeable to K+ than Na+ because K+ has more leaky channels - K+ leaks out, making the cell more negative preventing proteins from leaving, while some K+ re-enters, balancing the charge and preventing the inside from becoming too negative - Active transport maintains electrochemical gradients to keep cell in a steady state - Electro means charge difference across the membrane - Inside is more negative - Chemical means ion concentration gradient - More Na+ outside and more K+ inside the cell - Small amount of Na+ that leaks into the cell is countered by the active removal of Na+ keeping that balance - Plasma membrane Receptors - Receptors are important for allowing a cell to interact with its environment - Integral proteins at membrane surface serve as binding sites - Main functions: - 1) Contact signaling: cellular recognition by physical contact between cells - Importance: normal cellular development in particular to normal growth and immunity relies on contact signalling - 2) Chemical signaling: when a chemical messenger (ligand) binds a specific receptor and initiates a response - Overall process: ligand binds to receptor → receptor structure changes → cell proteins are altered - The specific response is linked to the cell’s structure and function, not the ligand itself - 1 ligand can produce a large amount of product which is energy saving Chapter 4 - Tissues Tissues: any grouping of cells that are similar (not identical) in structure and carry out a similar or common function - Organs must ave more than one tissue - Benefit: Tissues are more complex than individual cells which allows body to carry out complicated functions - Drawback: Destruction of one cell tissue cell will lead to the destruction of all 4 types of tissue - Nervous: control tissue - Muscle: movement tissue - Epithelial: covering tissue - Connective: support tissue Nervous Tissue - Control tissue: regulates and controls various body functions - Found in the brain (does most of the work), spinal cord, and nerves - Two cell types - 1) Neurons: capable of creating/transmitting electrical impulses through the entire body & can respond to various stimuli - Able to control resting membrane potential - Generating electrical impulse to rest of body - 2) Supporting cells: nonconducting cells → don’t produce electrical impulses - Function: protect, insulate, and support neurons Muscle Tissue - Movement tissue: allows for mobility (voluntary & involuntary) - Microfilaments actin and myosin filaments allow for muscle contraction/movement - 3 types of muscle tissue  - 1) Skeletal muscle: voluntary control with striations - Attached to bone via tendon, uses bone to produce movement - 2) Cardiac muscle: involuntary control with striations - Found only in the walls of the heart - 3) Smooth muscle: involuntary control without striations - Found in walls of hollow organs to move substances through organ - Rate determined by how full hollow organ is (stretch) Epithelial tissue AKA epithelium - General functions: - Boundary forming: separates one area/region of the body from another - Substances received or given off by the body must pass though this tiise - Two forms: - 1) Covering Epithelium: forms the covering of all internal and external surfaces of the body, lines body cavities & hollow organs - 2) Glandular Epithelium: makes up the glands of the body - Characteristics of Epithelial Tissue - Apical surface: borders open space. “Exposed side” → faces lumen or outside of body - Many have microvilli → used to increase surface area and absorption - Others have cilia → create current to propel substances through open space - Basal Surface: lies next to underlying connective tissue - Has attached basal lamina → filters out what can/cannot enter epithelial layer - Contact between neighboring epithelial cells - Joined by tight junctions (anchors cells together) and/or desmosomes (cellular velco, prevent epithelial cells from pulling apart) - Epithelial tissue forms sheets from cell junctions → prevents passage of material between cells & resists mechanical stress - Support for epithelium - Basement membrane lines the basal side of epithelial tissue - Lies between epithelial layer and connective tissue - Functions: reinforces epithelial sheet to resist stretching/tearing & defines epithelial boundary - Two layers: - 1) Basal lamina → sits closer to epithelium - 2) Reticular lamina → contains fibers that belong to connective tissue → helps further anker epithelial sheet in place - Avasucular → has no blood supply - Epithelial tissue recieves nourishment by diffusion - Innervated → supplied with nerve fibers - Helps control how much is secreted - High capacity for rregeneration  - Epithelial layers subject to high levels of abrasion (internal and external) - When epithelial tissue (skin cells) is damaged → cell reproduction begins quickly Classification of Epithelial Tissues - Based on 2 factors - 1) Thickness → number of layers - Simple Layer → only 1 layer of cells - **usually seen where absorption, secretion, filtration are desired - All these places require movement from point A→B - One layer → faster and more efficient - Stratified Layer → contains 2+ layers - Usually seen in areas of high abrasion - 2) Shape of cells - A) Squamous cells → “squashed” or “flattend” - B) Cubodial cells → cube - shaped - C) Columnar cells → tall, column-shaped - Simple squamous epithelium - Exceptionally thin and permeable - Function: absorption, secretion, filtration - Mesothelium: epithelium of pleura, pericardium, and peritoenum - Endothelium: forms stick/slippery lining of vessels - Ex: endothelium of blood vessels, allows blood to slide, less work for the heart - Simple cubodial epithelium - Tends to arrange itself in rings - Functions: absorption and secretion - Location: kidney tubules, ovary surfacem and some small glands - Simple columnar epithelium - Functions: absorption and secretion - Many have microvilli or cilia - Location: digestive tract, gallbladder, small bronchi, uterine tubes, parts of uterus - Pseudostratified columnr epitheliium - “False” stratified → nucleus lay is displaced, makes it look like multiple layers - All cells are in contact with the basement membrane - Only some cells stretch from the apical surface to basal surface - Function: secretion and absorption - **many type ciliated - Locations: respiratory tract, male ducts, ducts of large glands - Epithelial Class: Stratified Epithelia - General Characteristics → generates from the bottom up & good for protection - Starts from basal and pushes up to apical  - Stratified Squamous Epithelium → most come stratified layer - Thick, forms good protectictive barrier without being too thick - Basal cells almost constantly reproducing to replenish those that are rubbed off - Apical cells more poorly nourished → may even be dead - Locations: lining of mouth (chewing food scraping mouth), esophasgus, anal canal (waste leaving), and vagina; epidermis of skin - Stratified columnar & cubodial epitheium → rare because if too thick, nothing can pass through - Cubodial: rare, usually consist of just 2 layers - Locations: mostly ducts of sweat glands and mammary glands - Columnar: also rare with 2 layers - Only apical cells are columar → basal layer more cubodial - Locations: male urethra, part of pharynx, and some ducts - Transitional epithelium - Basal cells are mostly cubodial/columnar, apical cells vary - Location: mostly unirnary organs - Beneficial because urinary organs are changing shape constantly - Good at returning to original size and shape - Glandular Epithelia - Glands: one or more cells that produce and secrete a particular product called a secretion - Secretion: liquid substance that is produced by a body cell - Water base with proteins & other substances - Protein and substance components depend on cell type producing the secretion - Manufactured from the blood supply - Have to have vascularization to an extent - Classifed 2 ways: - 1) Location of releaase - Endocrine vs. exocrine - 2) Number of cells that makes up gland - Unicellular vs multicellular - Endocrine glands (ductless glands) - Secretion released directly into blood stream - Can form compact multicellular organs or diffuse endocrine systems - Mostly multicellular - Produce hormones → released via exocytosis - Hormones are chemical messengers → target specific cells/organs - Exocrine gland - Secretion released onto surfaces or into cavities - Ex: sweat glands goes through duct to be release to skin - Can be unicellular or multicellular  - Unicellular release secretion on surface via exocytosis - Multicellular release secretion onto surface via a duct - Ex: liver, pancreas, salivary glands, sweat glands, oil glands - Unicellular exocrine glands → not that many of them - Individual cells that are scattered through epithelia with other cells of different functions - Consist of a single cell that releases secretions - Ex: goblet cells (digestive system), mucous cells (respiratory system) - Both produce & secrete mucin → dissolves water to create mucus - Multicellular exocrine gland → more complex - Two basic parts of multicellular exocrine glands - 1) Acinus (acini) → secretory unit made up of cells that produce a secretion - 2) Duct → “tube” formed by cells of epithelium that allows secretion to be released to a surface - Classification of muliticellular exocrine glands: - 1) Structure - Simple: unbranched duct(s) - Compound: branched duct(s) - **Acinus can be tubular, alveolar, or tubuloalverlar → based on shape - 2) Mode of secretion - Merocrine glands: secretion entirely released via exocytosis from acini, cell remains unchanged when releasing secretion - Holocrine glands: secretion released as a result of cell rupture - Do not use exocytosis, produce and release substance, will continue to build until it burst - Oil glands → sebacous glands - Apocrine glands: similar to holocrine, but cells do not truly rupture - Will also fill until they tear open - Difference is that secretion just leaks out - Little damage and will repair Connective tissue - Most abundant and widespread of all tissues - Found in all organs & organ systems - Skin had alot of connective tissue - Nervous system does not have alot because it slows down nerve signals - Holds things in place - Characteristics - Possesses an extracellular matrix (ECM) - ECM is a nonliving matriz that separates living cells of the tissue  - All connective tissue arises from embryonic tissue called mesenchyme - Major functions of connective tissue: - Support - Protection - Insulation - Storage - Transport - All classes of connective tissues have 3 components** - 1) Ground substance: fills space surrounding cells & contains fibers - Made of - 1) Interstitial fluid (ISF): allows nutrients to pass from blood to cells (makes up most of ground substance) - 2) Cell Adhesion proteins: proteins acting like “glue” to hold living cells to ECM - 3) Proteoglycans: proteins that give ground substance it’s consistency - Consist of protein core with polysaccaride attachments - More proteoglycans = more viscous ground substance (thick) - Can make fluid, thinner or thicker - 2) Fibers: supportive structure of connective tissue - Types of fibers: - A) Collagen fibers - Assemble and cross-link with other collagen fibers spontaneously - Contain protein collagen - Strong, flexible - Resist pulling forces - Skin, tendons, ligaments - B) Elastic fibers: form branching networks - Long and thin - Contains protein elastin - Easily stretch, can return to normal shape - High density in areas of body that are subjected to frequent stretching - Skin and lungs (inhale ↑, exhale↓) - C) Reticular fibers - Shorter and finer than other fibers - Extensively branched to form fine networks - Continuous with collagen fibers  - High density in areas of body where connective tissue attaches to another tissue → good for holding things in place - Homeostasis Imbalance: Connective Tissue Fibers - Marfan Syndrome is a genetic disorder that affects the body’s connective tissue and causes an imbalance - Results from a mutation in the FBN1 gene, which codes the production of fibrillin. This protein contributes to strength and elasticity of connective tissue fibers - Fibrillin is important for production of elastic tissue - Causes elastic fibers of connective tissue to lose flexibility and strength - Since connective tissue is so widespread in the body, those affected by Marfan syndrome have several body systems affected like: - Bones/joints - Heart/blood vessels - Respiratory tract - Eyes - 3) Cells - Cells found in connective tissue can be immature cells (-blast) or mature cells (-cyte) - “-Blast” cells actively mitotic, lay down ground substance/fibers** - Ex: osteoblast cells in bone tissue - “-Cyte” cells maintain what is/was laid down by -blast cells - Ex: osteocytes cells in bone tissue - Makes sure theres not too much or too little connective tissue Types of Connective Tissue (4) - 1) Connective tissue proper: any connective tissue that is not bone, cartilage, or blood - A) Loose connective tissues (3 specific forms): - Areolar connective tissue: - Functions: supports/binds, nourishes, defends, stores - Chief cell type is the fibroblast - Ground substance is thick (more proteoglycans) - Location: almost everywhere - Adipose tissue: store alot of lipid, easily accessible to produce ATP - Function: easy-to access energy/nutrient source - High metabolic activity - Prevents heat loss - Subcutaneous → directly under skin - Chief cell type is the adipocyte - Limited matrix in adipose tissue - Reticular Connective Tissue - Forms stroma (supporting network of weeding tissues) to support free blood cells in lymph nodes, spleen, and bone marrow (all hold alot of cells)  - B) Dense connective tissue → fibers packed closely together - Dense regular connective tissue - Chief cell type is fibroblast - Collagen fibers run in same direction - High resistance to tension - Little ground substance - Location: found in tendons, aponeuroses, and ligaments - Dense irregular connective tissue - Collagen fibers are thicker than dense regular, irregular arrangement of fibers - Can also withstand tension - Can be pulled in different directions w/o it breaking - C) Elastic Connective tissue - Very elastic → tissue recoils easily after stretching - 2) Cartilage - Composed of chondroblast/chondrocytes - Flexible but still tough - Avascular, no innervation - No blood supply to cartilage, no nerve system supply - Get nuteints via diffusion - Ground substance is very thick/firm - Still contains large amount of water - 3 types: - Hyaline cartilage (most abundant) - Elastic cartilage (found where you need to stretch) → ear - Fibrocartilage (tightly pack → good for stability & withstanding pressure + knee) - 3) Osseous (bone) tissue - Found in bone → tissue contains inorganic calcium salts that make it rigid - Contains osteoblast and osteocytes - Bone salts deposit on/within fibers - Highly vascularized, innervated - Need required nutrients: oxygen, glucose, calcium etc. for sufficient bone growth and remodeling - 4) Blood (only fluid form of connective tissue) - Develops from mesenchyme, cellular portion is blood cells, fluid matrix is called plasma - Most cells are erthrocytes - Fibers form only during blood clotting - Fibers allow blood to stick, allowing clotting - Does NOT provide support or physically connect one tissue to another - Function: transport nutrients, waste, gases, etc. Covering and Lining Membranes - Simple organs of the human body  - Three types of covering & lining membranes - 1) Cutaneous (skin) - Composed of keratinzed stratified squamous epithelia - Dry membrane - Bacteria and etc. don’t survive on dry membrane - 2) Mucous membranes (mucosa) - Lines any body cavity that leads into/out the body - Ex: epithelial tissue that lines the digestive tract - Wet moist membrane - Epithelial cells attached to lamina propria (areolaar connective tissue) - Function: absorption/secretion - 3) Serous membranes (serosa) - Lines body cavities that are closed to the outside of the body - Remember serous membranes are named according to what cavity they are cling to - Serous fluid produced and secreted by cells in serous membrane Tissue Repair/Regeneration - Responses to invasion/injury can be inflammatory (localized) or immune (severe infection) - Cells in & around injury side must divide and migrate in order for repair to take place - Simple infection → tissue regeneration - Severe infection → scar tissue formation, clotting Homeostatic Imbalance of Tissues: Cancer - Cancer is the unregulated division of cells in the body - Results in a mass of cells called neoplasm (tumors) → benign or malignant - Malignant forms can become metastatic - Cells will break free & travel to another part of body & develop secondary cancer - Primary cause of cancer is a mutation in DNA that alters expression of multiple genes - Mutation causes by: lots of things - Oncogenes (mutated proto-oncogenes, uncontrolled cell proliferation, leads to cancer) vs. proto-oncogenes (completely normal genes, promote cell division, prone to mutation) - Tumer suppressor genes: suppress tumor growth by supporting cell division - Most common forms of cancer: skin, colon, lung, breast, prostate - Treatment: chemo (can also kill off healthy cells) and radiation (kills off malignent cells) Chapter 5 - Integument Pirmary Functions of the Skin - 1) Protection - A) Chemical - Sweat & oily secretions kill bacteria - Sweat is acidic so it can kill organisms on the skin - Melanin prevents damage caused by UV light - B) Physical - Skin prevents entrance of bacteria - C) Biological - Dendritic cells patrol dermis to stop anything that passes through epidermis - Macrophages destroy large-sized “invaders” - Specialize in phagocytosis (digesting large pathogens/debris) - Clear out debris so it can be replaced - 2) Temperature regulation - Insensible perspiration: unnoticeable sweat loss during the day - Important for temperature regulation (smaller changes) negative feedback mechanism - Sensible perspiration: noticeable sweat loss that occurs when excess heat needs to be lost by body - On warmer day, physical activity when you need to make larger changes to regulate temperature - When environmental temperature is cold, blood vessels in skin contrict → pulls blood away from the skin - Blood is mostly water and water absorbs heat - If external temp is low, blood will go to deep body tissues, and keep visceral organs warm (heart, liver, kidneys) - Process will help preserve internal body heat and keep visceral organs working - 3) Sensation - Exteroceptors: cutaneous sensory receptors - Respond to stimuli arising outside the body - Mechanoreceptors: respond to mechanical stress: touch, pressure etc. - Thermoreceptors: tells you when it’s warm or cold - Nociceptors: gives you a response of pain - 4) Metabolic functions - Involved in vitamin D production - Have to be exposed to sunlight to produce vitamin D - Important for calcium absorption - Helps with neurotransmitter release - Important for health of skeleton - 5) Blood Reservoir - ~5% of total blood volume can be found in integument  - Can be “moved” by central nervous system - Contrict or dilation of blood vessels so body temp is regulated - 6) Excretion/waste elimination - Sweat allows for some elimination of certain nitrogenous wastes (urea, ammonia, uric acid) Integument (Skin) - Two layers present in skin: - 1) Epidermis - Unvascularized, outermost portion - Made up of stratified squamous epithelia, 40-50 layers - 2) Dermis (thicker layer) - Vascularized - Makes up most of integument by mass - Hypodermis: made mostly of fat cells (adipose tissue) - Subcutaneous - Lies deep to the the dermis, but → not a true structure of the integument - Composed mostly of adipose tissue - Important functions: - 1) Storage: easy-to-access energy source for the body - Short on glucose can pull from adipose to make ATP - 2) Protection/shock absorption: prevents physical trauma to internal organs - 3) Insulation: prevents excessive heat loss - Serves thermal regulation function - 4) Anchor: holds skin to underlying muscle tissue - Is still flexible!! - Epidermis - Cell types found in the epidermis - 1) Keratinocytes: produce keratin protein - Keratin is a dry protein - why our skin is dry - Keratin is a tough protein - why our skin is tough - Linked by desmosomes (with some tight junctions) - Helps with preventing water loss - Reproduce mitotically in response to epidermal growth factor - Keep some of the keratinocytes active - Reproduce from the bottom up - Millions of cells lost/day → we “grow” new epidermis every 25-45 days - Persistent friction in certain areas of body = callus formation - Function: gives epidermis its protective qualities (tough & dry) - 2) Melanocytes  - Contain melanosomes - Produce melanin pigment, which is transferred to keratinocytes - Melanin migrates to the “sunny side” of keratinocytes - Which protects nucleus from sunlight - Melanocytes don’t keep the melanin they produce, they ship it off to keratinocytes - 3) Dendritic cells (Langerhans cells) - Immune system cells - Move to epidermis from bone marrow - “Presenting” cells → patrols the integument - If it comes in contact with some type of pathogen, it will bund to it and show it to other immune cells and tell them to kill off this pathogen if they see it - 4) Tactile cells (Merkel cells) - Present in epidermal - dermal junction - Tactile - in reference to touch - Associated with nerve endings → sensory receptor function - **can perceive light touch and vibration - Layers of the Epidermis - 1) Statum Basale (base layer): innermost layer - Simple layer of stem cells attached to dermis (single layer) - Rapid division of cells seen here - Regenerates from the bottom up, helps maintain the thickness of skin - Composed mostly of keratinocytes - 10-25% of cells are melanocytes - 2) Stratum Spinosum (spiny layer) - Stratified layer - Cells look spiny - Cells contain pre-keratin protein → thick bundles of filaments that resist tension - Pre-keratin not as strong as keratin - Dendritic cells are most abundant here - Desmonses here provide stong intercellular adhesion to have resist mechanical stress - 3) Stratum granulosum (granular layer) - Keratinization begins at this layer - Accumulation of two granule types in cells of this layer - Kertohyaline: helps with the formation of keratin in the upper layers of epidermis - responsible for binding keratin together to make tissue stronger - Lamellar granules: contains water- resistant glycolipid  - Glycolipids help prevent water loss from the skin (prevents dehydration) - Cells here are especially tough, and water resistant - 4) Stratum lucidum (cell layer) - Cells at this layer are not living - Avascular, rely on diffusion from underlying tissues to keep them alive - Dead but still joined together, preventing them from falling apart - Not found in thin skin - Skin on fingertips - 5) Stratum corneum (horny layer): outermost layer (30-40 layers) - Cells here are not living - Makes up most of the epidermal thickness - Heavily keratinized (super tough) - Glycolipids between cells help to waterproof this layer - Keratin inside cells protects from friction/abrasion - Melanin only deposited in the first 3 layers - Cells are dead and melanin only needs to protect the outside Dermis - The “hide” of the body - Made up of strong & flexible connective tissue - Fibroblasts & macrophages dominate here - Semifluid matrix - Makes dermis mobile - Fibers are abundant here - 2 layers make up the dermis: - 1) Papillary dermis - Thin areolar connective tissue - Fibers are thine so defensive cells can wander freely here - The papillary dermis forms peaks and valleys - Has projections called dermal papillae - Can have pain receptors or tactile corpuscles (sensory receptors) - Projections indent the overlaying epidermis → forms friction ridges - Genetically determined feature → fingerprint - 2) Reticular dermis - Lies deep to papillary dermis - Composed of dense irregular connective tissue - Lots of fibers - Forms cleavage lines in skin - Not visible externally - Lines formed by alternating dense & less dense regions of fibers - Surgeons will cut parallel to the cleavage lines - Forms flexure lines at/near joints  - Also called skin folds - Dermis is tightly anchored at the flexure line - and does not move as easily - Dermis is forced to fold, forming creases that are visible externally - Ex: palms of hands Skin Color - 3 pigments will determine skin color: melanin, carotene, & hemogloblin - 1) Melanin: polymer that comes in two forms (reddish yellow, brownish black) - Synthesized by protein called tyrosinase - Skin pigment is dependent on amount of melanin produced by melanocytes - Everyone has the same amount of melanocytes - Skin gets darker with exposure to sunlight - Keratinocytes release chemical to activate melanocytes - Tells melanocytes that they are damaged causing more melanin to be produced - 2) Carotene: yellow-orange pigment - accumulation of stratum cornem & adipose tissue - Can be used by body to produce vitamin A → used for vision, epidermal health - 3) Hemoglobin: pink/red pigment - Oxygenated pigment → color comes from blood supply to the dermis - Not a true skin pigment - Substance in blood that carries oxygen to your tissues - Melanin and carotene is darker in color so it can overpower the reddish-pink tint of hemoglobin - Homeostatic Imbalances of Skin Color - Skin color can be affected by genetics, diet, drugs, illness, etc. - Illness: Jaundice (liver failure) - Genetic: Albanism/melanism - Albinism eyes tend to be red because you can only see blood supply - Drugs: Argyria (silver) → consumption of silver turns you blue Skin Appendages - Are structures that are associated with skin (without actually being the skin itself) - 1) Hair (pili) - Grow from follicles - Two regions of a hair: - 1) Root: part of hair embedded in skin - prevent s hair from being shed or lost - 2) Shaft: part of hair projecting out of skin - Functions: - 1) Sensory structures: nerves associated with hair follicles - If something brushes against you - 2) Protection: scalp, eye, nose (filters bugs, dirt, etc.)  - Protects scalp from sun damage - Consist of dead, hard-keratinized cells - Keratin makes hair tougher - Hair has 3 layers: - A) Medulla: central core composed of large cells and air space - Absent in thin hair - Innermost region - B) Cortex: several layers of flatten cells - Individuals unable to stick to each other well, prevents hair from getting too thick - C) Cuticle: outermost layer that is most heavily keratinized - Cells in layer are stacked like roof shingles - Structures associated with hair: - A) Hair Follicle: Results from fold extending from epidermal surface into dermis - Each follicle is composed of 3 layers - 1) Peripheral sheath: outermost later composed of dermis - Gives hair it’s shape - 2) Glassy membrane: “basement membrane” joining the peripheral sheath to the root sheath - Root sheath could potentially turn outwards without a glassy membrane - 3) Root Sheath: innermost later derived from epidermis - B) Root hair plexus (refers to nervous system) found at base of hair follicle (hair bulb) - Contains nerve ending - Gives hair sensation, allows us to know what’s happening in the external environment - C) Dermal papilla: provides capillaries to hair follicle - You need blood supply in order to have hair growth - D) Arrector pili: smooth muscle cells attached to hair follicle - Contraction pulls hair follicles upright - Is what gives you goosebumps → no function in humans - Shape and color of hair - Shape of hair is dependent on hair follicle shape at skin surface: - Round = straight hair - Oval = wavy/slighty curly - Flattened = very curly/coiled - Color dependent on melanin deposition to cortex (outermost layer) of hair - Heavy deposition = darker hair - Exceptions: - Red hair results from pheomelanin - Gray/white hair: melanin production decreases with age, cortex fills with air bubbles instead  -Hair growth - Hair matrix: composed of rapidly dividing cells from hair bulb of the hair follicle - New cells push oil cells up and out - Most growth is cyclical → our hair goes through phases - Growth phase: hair making new cells and new cells pushes the old cells up - Resting phase: hair matrix is not active, hair is just sitting in follicle - Shedding phase: hair root physically detaches - Then will go back to growth phase - **all hair is not at the same phase → or we’d be bald - Types of Hair: - 1) Vellus hair: thin/fine hairs - Amount dependent on age and sex - Infants and children tend to have more vellus - Tend to only find vellus hair in females - 2) Terminal hair: thick/coarse hairs - Typically darker in color than fine hairs - More common on adults, particularly males (beard hair) - Hair loss/balding - Hair thinning is experienced by most people at older ages → hair loss exceeds hair replacement - True baldness is usually influenced by the sex chromosomes and genetically determined (“male-pattern baldness”) - Hair follicles respond to androgen hormones differently with time → hair become vellus (thinner) may shed before emerging from the follicle - **Males are more likely to be bald because they only have one X chromosome, so they have nothing to buffer it - 2) Nails - Found on distal portions of fingers and toes → made up of dead cells - Contain hard keratin → what makes them so tough - Composed of root, nail plate, free edge - Nail matrix responsible for nail growth - Function: protective covering for distal portions of fingers and toes, contributes to dexterity Skin Glands - 1) Sweat Glands - Cells in sweat glands are myoepithelial cells - Myo - muscle → able to contract - Specialized cells that will contract when stimulated - Squeezing sweat to the surface - Secretory cells pull materials needed to produce sweat from blood - Mostly water, but also contains salts, metabolic wastes, etc.  - Two types: (both merocrine in the mode of secretion) → release sweat via exocytosis - A) Eccrine Glands: especially abundant on palms, soles of feet, forehead - More common, mostly found on your forehead - Simple tubular glands that open directly to skin surface at a pore - Simple coiled tubes - Sweat is mostly water - Function: body temperature regulation, when sweat evaporates it takes heat with it - B) Apocrine Glands: located in axillary (armpit) and anogenital area - Empty into hair follicles, then released to the skin - Eccrine empties straight to skin, apocrine has to be released via hair - Same components as sweat from eccrine glands - Some also have some fatty substances (lipids) & proteins - Function: ??? is unknown - Based on other animals its a sexual sex gland - Modified versions of this gland include ceruminous glands and mammary glands - Ceruminous glands found in ear canals (ear wax) - Prevents insects from crawling into ear - Mammary glands only active and present in females during pregnancy and shortly after birth - Fun fact: where you begin to sweat depends on the circumstance! - 2) Sebaceous glands (oil glands) - Secretes sebum (oily substance) - Sebum is largely lipid-based with some cell components and is released to the skin’s surface - Function: - Lubricant for skin/hair - Prevents skin and hair from drying out - Slows water loss from the epidermal surface - Kills bacteria ​→ prevents infection - Homeostatic Imbalance of Skin: - Skin Cancer - Skin exposed to excess amounts of UV light overtime may have some cells become cancerous - This is *the* most common type of cancer - In US → 9,500 diagnosed with cancer **per day** - 3 major forms of skin cancer - 1) Basal cell carcinoma - Most common form, but least malignant - Slow-growing, metastasis rarely occurs  - Cells in stratum basale proliferate - Found mostly on face, often colorless with “rolled” edges - 2) Squamous cell carcinoma - Second most common - Fast growing - Will usually metastasize if left untreated - Cancer of keratinocytes of stratum spinosum - Appears as flat, a scaly, red lesion on skin - Looks like wound that never heals - Found mostly on head (not facial area) and hands - Behind ears, scalp - 3) Melanoma - Lowest amount of overall skin cancer cases, but causes the most skin-cancer related deaths - Metastasizes quickly & can be chemo-resistant - Early detection is key - Use the ABCD(E) rule - A - asymmetry - difference in color - B - border - any jagged borders - C - color - cancerous moles are brown, black, blue, red, etc. - D - diameter - any spot that is greater than 6mm thats cancer! - E - evolving - rapid change in short period of time, if it changes color/size = abnormal growth - Burns - Types of burns: Refers to exposure caused by heat or chemicals - 1) 1st degree burns: painful, reddened skin, inflammation - No scarring/fibrosis involved in health - Skin not actually broken - Ex: sunburn → peeling is from the burned skin but there is new epidermis under it - 2) 2nd degree burns: pain, redness, fluid pouches (blisters) - Fluid separates the epidermis and underlying dermis - Blister allows a new layer of episdermis to be laid down - Unroofing = peeling blister before it’s ready - Takes longer to heal compared to 1st degree burn - No scarring/fibrosis → if not picked at - 3) 3rd degree burn: full thickness burns - Haven burnt away epidermis as well as dermis - Lose their glands and sensory fibers in that area so they can’t feel pain there - Treatment usually requires IV fluids, skin grafts, heavy antibiotic use - Fibrosis occurs during healing of burns → has to occur  - Any burn more than 10% is considered critical condition - Skin graft (epidermis and dermis) doctors don’t want to mismatch thin and thick skin - Ex: extreme heat, severe chemical/radiation exposure - **number one cause of death is dehydaration → lose fluid in body Chapter 6 - Bones and Skelatal Tissuey - Chondr- “cartilage” - Osteo- “bone” Functions of Bones - 1) Support - Holds up the body - Cradles organs → ex: hip bone - 2) Protection - Central nervous system - The skull protects the brain - Vertebrae wraps around spinal cord - Visceral organs - Rib cage wraps around organs in thorax & upper abdominal cavity - Protects heart and lungs - 3) Attachment point - Skelatal muscles attaches to bone via tendons - Tendons are dense regular tissue - Each time muscle contracts its going to pull a bone which is going to allow movement - 4) Storage - Minerals - calcium and phosphate - Calcium gives bone that hard texture - Fat (adipose tissue) - Yellow marrow in bones of adults - Called yellow because adipose tissue has yellow in it - 5) Blood cell formation - Hematopoiesis → formation of blood cells in red bone marrow - Includes red and white blood cells as well as platelets - 6) Hormone production - Osteocalcin → regulates insulin release, glucose homeostasis & energy expenditure - End result: increased insulin secretion from the pancreas, improved glucose regulation, enhanced energy expenditure Types of Cartilage - All 3 types of cartilage have 2 basic components - Chief cell type is chondrocyte - Types of cartilage  - 1) Hyaline: most abundant type - Chondrocytes are spherical - Contain collagen fibers - Ex: Articular (ends of long bone like knees, hips, elbows), costal (ribs to sternum), respiratory (larynx, trachea, brochi), nasal (nose) - 2) Elastic - Similar to hyaline, but contains more elastic fibers - Ex: external ear, epiglottis - 3) Fibrocartilage - Contain rows of chondrocytes alternating with thick collagen brands - Most compressible, great tensile strength - Ex: vertebral discs, knee, pubic symphysis - Types of Growth - 1) Appositional: laying down new cartilage on old cartilage - Cells just under perichondrium deposit new matrix on top of “old” cartilage - Occurs at surface of cartilage tissue - 2) Interstitial: “growth from within” - Cells divide and secrete matrix in pre-exisiting cartilage - O