Exam 1 Flashcards

Question

medial

Answer 1

closer/toward or at midline of the body; on the inner side

Answer 2

Farther from the origin of the body part or point of attachment of limb to trunk of body

Answer 3

closer to the origin of the body part or point of attachment of limb to body trunk

Answer 4

toward to at the body surface

Answer 5

away from the body surface, more internal

Answer 6

Toward head end or upper part of a structure or the body

Answer 7

away from head end or toward lower part of a structure or the body

Answer 8

divides body into left and right -median/midsagittal plane divides body exactly in half

Answer 9

divides body into anterior and posterior

Answer 10

divides body in superior and inferior parts

Answer 11

most organs found in one of the body cavities -protects organs of the central nervous system --composed of cranial cavity

Answer 12

houses visceral organs composed of: -thoracic cavity: contains heart and lungs -abdominopelvic cavity: separated from thoracic cavity diaphragm

Answer 13

serous membrane (serosa): double-layered membrane

Answer 14

innermost layer covering the organ

Answer 15

outer lining the body wall of the cavity -these 2 layers of serosa are separated by small amount of serous fluid

Answer 16

1. Pericardium: serous membrane surrounding heart 2. Pleura: surrounding lungs 3. Peritoneum: surrounding most organs of abdominopelvic cavity

Answer 17

any substance containing 2 or more components physically intermixed `

Answer 18

homogeneous mixtures that can exist as a solid, liquid, or gas composed of very small particles that do not settle out

Answer 19

dissolving medium (usually in greater amounts) -water is bodys primary solvent

Answer 20

dissolved in solvent (do not settle out/don't float to bottom of solution and remain suspended)

Answer 21

heterogeneous mixture 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) --Ex: cytosol(the aqueous component of the cytoplasm of a cell, within which various organelles and particles are suspended) of cells changes consistency depending on certain cell activities (cellular division, changes in shape, etc)

Answer 22

heterogeneous mixture composed of large solute particles that DO settle out -Ex: blood contains a fluid portion (called plasma) with various cell types (red blood cells, white blood cells, and platelets) suspends it

Answer 23

occurs when bonds are formed, broken, or rearranged types: 1. Synthesis reaction 2. Decomposition reactions

Answer 24

formation of bonds between atoms or molecules from larger, more complex structures -Are endergonic→ contains MORE energy after formation --Ex: anabolic reactions in body

Answer 25

bonds are broken to create smaller molecules or individual atoms -Are mostly exergonic→ RELEASE energy when bond is broken --Ex: catabolic reactions in body

Answer 26

1. Water 2. Salts 3. Acids and Bases

Answer 27

A. universal solvent --Transport→ water carries nutrients, respiratory gasses, metabolic waste, etc. --Water can surround some charged structures (ex: large proteins) to prevent interactions with other charged particles Prevent negatively charged particles and shells it off from doing something it shouldn't be doing yet B. High heat capacity --Can absorb and release large amounts of heat with little charge to its own temperature by 1o C --Water needs to absorb a massive amount of heat to increase 1o C C. Protection --Water based body fluids provide a “cushion” for internal organs --Water takes blow to prevent damage from internal organs D. Heat of vaporization --Large amounts of heat must be absorbed to break bonds and cause evaporation --Important for body temperature but specifically for sweating and body cooling ---Sweat is very good and letting out a lot of heat and prevents internal temperature from getting too high E. reactive --Water is used in several chemical reaction in the body ---Hydrolysis reaction -----(adding water to compound to break bonds) -----AB + H2O → A-H + B-OH vs dehydration synthesis ---Remove water to form bonds

Answer 28

Dissociate in solution to form electrolytes -Importance: electrolytes Na+ and K+ allow for muscle contraction and transmission of nerve impulses, Fe+ used to carry out O2 -Iron-found in red blood cells and binds to oxygen in lungs -Na+ and K+ send nerve impulses and contribute to responsiveness and without them the nervous system won’t function as its should and muscle cells can contract as they should

Answer 29

Also from electrolytes -Acids: release H+ ions in solution --Cause pH to drop -Bases: release OH- ions in solution --Cause pH to increase -Optimal blood pH is 7.2-7.4 -If blood pH drops too low during acidosis or become to high during acolotise the chemical reactions stop or go at a speed that isn't able to sustain life -Potential problems: high/low pH disrupt cellular activity, hydrogen bonds --Solution? Buffers ---Weak acids release some H+ -----When blood pH is too high -----Strong acid release all H+ ions (SO NOT THIS) ---Weak bases tie up excess H+ when pH becomes too acidic ---Result: buffers prevent large changes in pH that could cause excessive damage in body

Answer 30

-All organic molecules contain carbon 1. Its electroneutral→ it neither gains nor loses electrons 2. Can form molecules of various shapes that all have specific functional in body --Long chains are tough --Rings found in lipids, carbohydrates, DNA -Macromolecules: polymers that are made up of several smaller, identical subunit called monomers --Carbohydrate, protein and fats are large complex molecules made up of monomers

Answer 31

Macromolecules sugar and startches Monomer: monosaccharide -Monosaccharides: glucose**(used for atp production), fructose, galactose -Monosaccharides can form disaccharides, polysaccharides --These 2 can't be used direclty for enery by body bc they are too large and complex -- Polysaccharides can be the external surface of cells and are different from everyone else. They increase efficiency of own body cells compared to something that could potentially be disease causing Major functions: -Fast, easy to use energy source -Cell cell interactions → carbohydrates attached to cell surface used to communicate

Answer 32

Macromolecule: monomerL fatty acids and glycerol Varieties -saturated→ contain only single covalent bonds, molecules packed close together --Ex: fat in meat products --Solid at room temp --Doctors recommend not eating too much because it can be solid in the body and potentially decrease blood flow to the body. Increase risk of heart attack -Unsaturated→ contain 1 or more double covalent bonds, molecules more spread out --Ex: most plant based oils --Can consume in higher amounts with less concerns -Trans fat→ oil fats that have a H added to sites of double bonds --Ex: doughnuts, cookies --Worst and unhealthiest of all the fats -Omega 3 fatty acids: oil fat found in cold water fish Ex: krill oil, fish oil capsules Healthiest of fats -Major functions: protection, insulation, fast and easily accessible energy storage -Triglycerides are stored in fat tissue and give us protection and can absorb shock (adipose tissue). This tissue is also insulation to prevent excessive heat loss. -Body can use triglycerols to produce atp if not enough glucose, but not as good bc doesn't produce as much atp

Answer 33

Macromolecule Modified triglycerides with 2 fatty acid chains and a phosphate group --Fatty acid chains are hydrophobic --Phosphate “head” is hydrophilic Major functions: used to build cell membranes (phospholipid bilayer)

Answer 34

Macromolecule Most important: cholesterol -Ingested in eggs, meat, cheese --Only need to ingest 15%, other 85% comes from liver -Liver produces cholesterol Major functions: structural components of cell membranes, is “base: used by body to form other steroids (steroid hormones-testosterone & estrogens, corticosteroids)

Answer 35

Macromolecule Monomers: amino acids -Specific amino acid sequences leads to large variety of protein functions Strucutre determines function

Answer 36

Form long strands that can link together to for long, stable structures -Function: provide mechanical support and tensile strength, some contractile ability -Contracting anf then going back into shape -Ex: collagen, muscle, tendons and ligaments

Answer 37

Compact, spherical in shape Chemically active Function: transport molecules, immune defenses, regulation of growth and development Making sure cells divide and stop when they should

Answer 38

Biological catalyst Function: catalyst lower activation energy of chemical reactions Varying degrees of specificity -Some only catalyze 1 reaction, others can catalyze multiple reactions Importance; without enzymes, most reactions would either not occur or would occur too slowly to sustain life

Answer 39

Adenosine triphosphate (ATP) is the energy transfer molecule of any body cell --Need electron transport chain and oxygen (glucose) ATP has triphosphate tail that has high bond energy -When phosphate tail is transferred to another molecule, that molecule temporarily has more energy to do work -atp molecule transferred tail to enzyme so the enzyme will temportaly by connected to tail and given energy to do work. Ince the tail breaks off, the enzyme does nothing until it gets another phosphate tail ---While doing the work, the molecule loses the phosphate group -ATP storage and release is similar to energy needed to drive most chemical reactions --A cell will only produce as much ATP as it needs at one time, nothing more --Storage ATP is wasted energy bc it takes ATP to produce ATP, so if you are producing it and let it sit and do nothing, so it produces what it needs (body doesn’t like excess waste) Importance: without ATP, chemical reactions stop, cell transport stops, muscle cannont contract→ death occurs

Answer 40

Prefix: Cyto (ex: cytoplasm) Suffix: cyte (ex: osteocyte) The cell is the smallest living unit of life * Different types of cells have different functions in the body * Loss of homeostasis in cells often leads to disease

Answer 41

1) Plasma membrane: outermost boundary, selectively permeable 2) Cytoplasm: intracellular fluid * Mostly water, but also contains salts and organic molecules 3) Nucleus*: controls cellular activities

Answer 42

The Fluid Mosaic Model describes the the general structure of the plasma membrane * Plasma membranes consist of a phospholipid bilayer with proteins randomly dispersed in it and maks up most of mass * phospholipid bilayer so thin it's almost fluid ---makes membrane more flexible and allows it not to tear * Importance: separates the intracellular fluid (ICF) from the extracellular fluid (ECF)

Answer 43

1. Lipids 2. Proteins 3. Carbohydrates

Answer 44

forms basic structure of membrane * Polar Phosphate head: hydrophilic portions contact intracellular or extracellular fluid * Nonpolar Fatty acid tails (2): hydrophobic portions that face the inside of the membrane * Aggregation of hydrophobic and hydrophilic regions leads to ability of cells to reseal when damaged/torn

Answer 45

provide structural support to “stiffen” the membrane-->increases membrane stability *stick it in the plasma membrane, it makes it tougher/stiffer--> reduces likelihood of plasma membrane tearing easily

Answer 46

Constitute most of the specialized membrane functions *categorized by location

Answer 47

Location *embedded in the plasma membrane * Transmembrane proteins span the entire width of the membrane-not all need to expand width * Major functions: transport, carriers, enzymes, receptors, cell- cell recognition, carry out chemical reactions, etc.

Answer 48

Location *loosely attached to integral protein * Are not found *in* the lipid bilayer * Major functions: enzymes, motor proteins, cell-cell attachment

Answer 49

Function protein move substances in and/or out of cells * Some proteins (left) form channels through which a particular solute can be selectively moved --*selective & transport certain substances depending on what substance is (ex. water, potassium) --* also selective on shape, some need to change shape) * Other proteins (right) actively pump substances across the membrane surface by using ATP *carrier proteins * tube straight through = channel proteins

Answer 50

Function protein *Can relay messages to cell interior when protein is bound to/exposed to certain chemical messengers * Specificity to chemical messengers can vary * some need to bind to several signals to change shape while some can only bind to one message * When bound to chemical messengerprotein changes shape, leading to series of changes inside the cell * Ex: receptor protein binds to hormonecellular activity changes

Answer 51

Function *proteins that catalyze chemical reactions * Some enzymes act alone, others may act as a “team” to catalyze sequential steps *vary in specificity (some carry out 1, some do more)

Answer 52

Function protein *allow body cells to recognize other body cells *bottom is glycoprotein; top is cell-cell recognition *immune system (ours vs outside body cells)

Answer 53

*helps hold some membrane proteins in place, maintains cell shape * Can be located inside of the cell or outside, depending on function *plasma membrane can contribute to structure of cell, shape, or hold

Answer 54

* some proteins are used to link cells together * Length of time to link cells varies --*movement of cells = millisecond binding --*long time bonding = tissue bonding * Major function: Assists with cell migration

Answer 55

*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 be used by immune cells to identify “self” cells from “non- self” cells * Can also contribute to structure/shape of cell membrane

Answer 56

*a class of proteins that provide contact or adhesion between two or more cells * Can be permanent or temporary

Answer 57

proteins in cell membranes of neighboring cells fuse together * Junction is impermeable --*nothing can pass through it --*Ex: prevent gastric juice from "leaking" due to tight junctions b/w epithelial cells of stomach * Ex: tight junctions between epithelial cells of stomach prevent gastric juice from “leaking out”

Answer 58

*anchoring junctions from one cell to another that prevents separation * Function: Bind cells together to form sheets that resist shearing forces when pulled/stretched * Components of a desmosome: --* Cadherins: protein filaments extend from cell surface and link to filaments on other cell surface --* Inside the cell, a plaque holds the cadherins in place --* Keratin filaments hold plaque in place to prevent excessive movement/shifting

Answer 59

*“communication” junctions * Intercellular channels between two cells * Hollow cylinders (formed by proteins) connect adjacent cells --* Different proteins used to create gap junctions = selective passage of molecules/substances through channels

Answer 60

*movement of molecules across the membrane down their concentration gradient (diffusion) with no ATP required * Driving force of diffusion: kinetic energy of molecules * In areas of high molecule concentrationmolecules collide & bounce off one another more frequently --*In areas of high concentration --> molecules collide/bounce off 1 another more frequently --*higher frequency = faster diffusion

Answer 61

1) Concentration: greater concentration difference between two areas leads to faster diffusion --*faster bc faster rate * 2) Molecular size: smaller molecules diffuse faster --*increase in KE = smaller molecules (move fast and diffuse faster) --*decrease in KE = larger molecules (move slower) * 3) Temperature: higher temperatures result in faster diffusion rates --*higher temp = higher KE= faster diffusion rate --* lower temp = lower KE=lower diffusion rate

Answer 62

*diffusion of substance directly through the lipid bilayer * Most molecules diffusing are small in size & nonpolar(fat soluble NOT water soluble) * -small size substances pass through -----Ex: gas, steroid hormones, fatty acids * Ex: most gases, steroid hormones, fatty acids

Answer 63

diffusion of molecules through the membrane with the use of a protein

Answer 64

*transmembrane proteins used to carry large molecules through the membrane * Protein changes shape while moving substance (open on one end and closed on other) * Limits: the cell can only move substances as fast as proteins become available to move them * 1 binding site = one substance

Answer 65

transmembrane proteins form water-filled channels through which molecules can pass * selective-->size of channel determines what ---Some transport just water and pottassium substance can/cannot pass through * Proteins can form leaky or gated channels *allows polar molecules through

Answer 66

*diffusion of water through a selectively permeable membrane * Movement of water across a semipermeable membrane from a less concentrated solution into a more concentrated solution until concentration is equal on both sides of the membrane * Can occur without proteins or with the use of aquaporin proteins *Low solute concentration to high soluble concentration and will continue until equilibrium is reached *can occur without proteins or w/ use of aquaporin proteins (channel proteins) *Water moves by osmosis until hydrostatic pressure (the pressure of water pushing on the inner cell wall) is equal to osmotic pressure (tendency of water to move into a cell by osmosis) * When the two pressures are equal-->no net movement of water is observed *Imbalances in osmosis cause body cells to swell or shrink (depending on total water volume inside cell)

Answer 67

*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 low osmolarity * One solute particle displaces one water molecule *solute with higher osmolarity = higher number of solute particles than solution w/ lower osmolarity

Answer 68

*Ability of a solution to change the shape of a cell by altering the cells 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!!!!

Answer 69

*have the same concentration of nonpenetrating solutes as those found inside the cell * No net loss or gain of water observed Ex: 0.9% NaCl solutions, extracellular fluid

Answer 70

*Have a higher concentration of solutes than inside the cell * Water moves out/cell lose water of the cell *Cell will “shrivel up” or crenate * Ex: 10% NaCl solutions

Answer 71

*have a lower concentration of solutes than inside the cell * Water moves into the cell/cell takes in water *Cell will ”swell up” until they burst (lyse) * Ex: distilled water

Answer 72

*Movement of molecules across the plasma membrane that requires energy input (use of ATP) *Molecules may be too big, too charged, insoluble in lipid membrane, or moving against their concentration gradient *Active transport requires transport proteins

Answer 73

*use of a transmembrane protein and ATP to move molecules across the plasma membrane against their concentration gradient * Two types of active transport: * 1) Primary active transport * 2) Secondary active transport

Answer 74

*energy required to do work comes directly from ATP hydrolysis by transport proteins called pumps * Hydrolysis of ATP leads to transfer of phosphate group from ATP to the pump * Phosphorylation of pump leads to a change in proteinshape--> allows protein to move molecule across the membrane * Important example: Sodium-potassium (Na+ - K+) pump * Uses enzyme Na+ - K+ ATPase enzyme

Answer 75

*Pumps Na+ and K+ against their gradients & in opposite directions across the membrane * For each ATP molecule, ATPase moves 3 Na+ ions, 2 K+ ions * Importance: ATPase pumps maintain electrochemical gradient necessary for function of muscle and nervous tissue

Answer 76

*indirectly uses energy stored in concentration gradients of ions created by primary active transport * Example: Moving Na+ out of cell creates concentration gradient * Cotransport protein pumps Na+ back into the cell, and carries another molecule with it --*cotransport drives glucose against its concentration gradient into the cell

Answer 77

movement of 2 transported substances in the same direction

Answer 78

movement of 2 transported substance in the opposite direction

Answer 79

Movement of one substance

Answer 80

*movement of fluids with large particle & macromolecules inside membranous sacs called vesicles Functions: 1) Endocytosis-movement of substances INTO the cell 2) Exocytosis-movement of substances OUT of the cell 3) Transcytosis-movement of substances into, across, then out of a cell 4) Vesicular trafficking-movement of a substance from one area of the cell to another

Answer 81

Vesicular transport used to bring substance INTo the cell from the ECF (extracellular fluid) *Begins with formation of infolding of plasma membrane

Answer 82

*cells engulfs large and/or solid material *Forms vesicle called phagosome --*Pseudopod formation involves receptors--> formation is specific * Phagosome usually fuses with lysosome, where contents are digested

Answer 83

*cell brings in a small volume of extracellular fluid containing small solute particle *no receptor use needed--> Endocytosis is NOT a specific process

Answer 84

*Allows endocytosis of SPECIFIC substance to occur *Extracellular substances bind to specific receptor proteins *Importance: Substances can be specifically concentrated in in vesicles & brought into cell *Fate of contents: A) Substance can be distributed through the cell B) Vesicle can fuse with lysozyme for digestion of concentrated substance

Answer 85

Vesicular transport used to REMOVE substances from cell to ECF

Answer 86

*Created around the substance to be removed * Secretory vesicle travels to plasma membrane, fuses with it, and dumps contents out of the cell * Functions: hormone secretion, neurotransmitter release, mucus secretion, waste removal, etc. etc

Answer 87

* Selective permeability of plasma membrane generates a membrane potential (voltage) across the membrane

Answer 88

*electrical potential energy resulting from separation of oppositely charged particles (ions)

Answer 89

*Voltage difference across cell membrane when cell is at rest *Average of -70mV All cells are electrically polarized -Negatively charged inside -Positively charged outside

Answer 90

* Creation of membrane potential involves an ion imbalance on either side of the plasma membrane * Ion concentrations of Na+ and K+ are different on either side of the membrane * -----Na+ concentration is higher outside the cell * -----K+ concentration is higher inside the cell * Potassium ions (K+) have a pivotal role in creating the resting membrane potential * -Plasma membranes are more permeable to K+ than to Na+ * -K+ “leaks” out of cell, proteins remain inside the cell * -The more K+ that leaves, the more (-) charged the inside of the cell becomes * -Some K+ ions will enter the cell--> prevents inside of cell from becoming too negative

Answer 91

* Active transport maintains electrochemical gradients to keep the cell in a steady state * What allows for the active transport? * Electro=charged * Chemical=ion concentration

Answer 92

*Cells can respond to both extracellular chemicals (hormones, neurotransmitter) and to other surrounding cells * --These interactions are used to maintain homeostatic balance in the body * Plasma membrane receptors are important for allowing a cell to interact with its environment

Answer 93

Integral proteins at the membrane surface serve as binding sites Main Functions: 1) Contact signaling 2) Chemical Signaling

Answer 94

*cellular recognition by physical contact between cells * Importance: normal cellular development and immunity rely on contact signaling

Answer 95

When a chemical messenger (called a 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 internal machinery (its structure & function), not the ligand itself * What does this mean about a ligand and its effect on different types of cells? * Example: G protein-coupled receptors

Answer 96

1) Ligand (1st messenger) bind to receptor. The receptor changes shape and activities 2) the activated receptor binds to a G protein and activates it. The G protein changes shape, causing it to release GDP and bind GTP (an energy source) 3) Activated G protein activates (or inactivates) an effector protein by causing its shape to change 4) Activated effector enzymes catalyze reactions that produce 2nd messengers in the cell 5) Second messengers activate other enzymes or ion channels. Cyclic AMP typically activates protein kinase enzymes 6) Kinase enzymes activate other enzymes. Kinase enzymes transfer phosphate groups from ATP to specific proteins and activate a series of other enzymes that trigger various metabolic and structural changes in cell.

Answer 97

*Any grouping of cells that are similar in structure and carry out a similar or common function *Benefit: cellular specialization allows the body to carry out complicated functions * Drawback: destruction of one cell type could be catastrophic

Answer 98

1) Nervous Tissue: control tissue 2) Muscle Tissue: movement tissue ---these 2 good w/ excitability & responsiveness 3) Epithelial Tissue: Covering tissue (bounding forming) 4) Connective tissue: support tissue (hold individual organs together)

Answer 99

*regulates & controls various body functions (send electrical impulses) --found in brain, spinal cord, and nervous system 2 cell types: -1)Neurons: capable of creating/transmitting electrical impulse -2)supporting cells: non-conducting cells ---function: protect, insulate, & support neurons -----dispose waste product

Answer 100

*Allows for mobility (voluntary & involuntary) *Microfilaments actin & myosin allow for muscle contraction/movement 3 types: 1)Skeletal muscle tissue: voluntary control w/ striations --attach to bones, use bones to produce movement (tendons) pills on bones 2) Cardiac muscle: involuntary control w/ striations --found only in walls of heart 3) smooth muscle: involuntary control w/o striations --found in walls of hallow organs to move substance through organs --cells look smooth -we dont control any of our smooth muscles --more stuff organ has, more frequently the muscle will contract

Answer 101

General function: *boundary forming: separates 1 area of body from another *substances received or given off by the body must pass through this tissue --small intestine through epithelium that lines it into the bloodstream 2 forms: 1) Covering: forms covering of all internal & external surfaces of body cavities & hallow organs 2) Glandular: makes up glands of body

Answer 102

*Apical - base polarity (boarders open space) --apical surface is "exposed" side--> faces the lumen or the outside of the body --many have microvilli--> used to increase surface are by adding extra plasma membrane --others may have cilia --> create current to propel substances through open space. *Basal surfaces: attaches to connective tissue (lies next to underlying connective tissue) --has attached basal lamina--> filters what can/cannot enter epithelial layer *connect between neighboring epithlial cells --Joined by tight junctions &/or desmosomes --E.T. forms sheets from all cell junctions--> prevents passage of material

Answer 103

*Basment membrane lines basal side of e.t. --lies b/w epithelial layer and connective tissue -function reinforces epithelial sheet to resist stretching/tearing and defines epithelial boundary *2 layers: 1) Basil Lamina 2) Reticular lamina: contains fibers that belong to connective tissue.

Answer 104

*Avascular--> no blood supply --e.t. receives nourishment by diffusion *Innervated--> supplied w/ nerve fibers --allows brain to receive info about e.t. *Increased capacity for regeneration --epi. layers get high levels of abrasion, hostile conditions (internal & external)

Answer 105

1) Thickness--> number of cell layers presnt in epithelia --A) Simple layer: contains one layer of cells ----usually seen where absorption, secretion, filtration, are desired --B) Stratified layer--> contains 2+ layers of cells ----seen where absorption & friction common (protects it from wasting through e.t. in short period of time) 2) Shape --A) Squamous cells--> "squishes" or flattened ----*nucleus also flattened --B) cuboidal cell-->cube shaped --C) Columnar cells --> column like, tall

Answer 106

*Simple Squamous epithelia --exponentially thin & permeable ----absorption, secretion, filtration 2 Designated names: -1) Mesothelium: epi. of pleura, pericardium, & peritoneum (covers abdominal organs) ----thin sheet -2) Endothelium: forms slick/slippery inner linings of vessels ----Ex: endothelium of blood vessels

Answer 107

Function: absorption & scretion Location: kidney tubles, ovary surfaces, & small glands looks like cheerio

Answer 108

*Absorption & secretion *Have microvilli or Cilia Locations: Digestive tract, gallbladder, small bronchi, uterine tubes

Answer 109

*False stratified *all cells in contact w/ basement membrane ---only some cells stretch from apical surface to basal surface *Function: secretion & absorption ---many types ciliated *Location: respiratory tract, male ducts, ducts of larger glands

Answer 110

*Regenerate from bottom up & good for protection

Answer 111

*Most Common *most widespread of any stratified layer *thick, forms good protective barrier w/o taking too much space *Basal cells almost constantly reproducing to replenish those rubbed off *Apical cells more poorly nourished--> may even be dead *locations: lining of mouth, esophagus, anal canal, Vagina, epidermis of skin

Answer 112

-Cuboidal: rare, usually 2 layers -Location: Most ducts of sweat glands & mammary glands -Columnar: Rare w/ 2 layers -only apical cells are columnar -location: male urethra, part of pharynx, some ducts

Answer 113

*Basal cells mostly cuboidal/columnar, apical cells varies *Location: urinary organs --Bc of location doesn't follow shape rules *constantly change zie and shape w/ bladder & not be damaged & return to original size once empty

Answer 114

*Glands 1 or more cells produce & secret particular product called secretion

Answer 115

*Liquid substances that produce by a body cell -*water base w/ proteins & other substances ---protein and substance components depend on cell type producing secretion -*manufactured from blood supply

Answer 116

1) Location of release -*Endocrine vs Exocrine 2) Number of cells that make up gland -*Unicellular vs multicellular

Answer 117

*Secretion directly into bloodstream via exocytosis from all *can form compact multicellular organs or diffuse (individual cells scattered across cells or in one organ) endocrine system --mostly multicellular *produce hormones--> via exocytosis ----hormones are chemical messengers--> target specific cells/organs

Answer 118

*Secretion released onto surface or into cavities *can be unicellular(Secretion via exocytosis) or multi (release secretion onto surface via duct) -EX: pancreas, liver, salivary glands, sweat glands, oil glands

Answer 119

Individual cells scattered through epithelia w/ other cells of different functions -EX: goblet cell (digestive system), mucous cells (respiratory system) ----Both produce & secrete mucin-dissolves in water to create mucus

Answer 120

2 Basic parts -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

Answer 121

1) Structure -* simple unbranched duct(s) -*compound branched duct(s) ----**Acinus can be tubular, alveolar, or tubuloalveolar 2) Mode of Secretion *Merocrine glands: secretion released via exocytosis from acini, cell remains unchanged when releasing secretion * Holocrine glands secretion released as result of cell rupture *Apocrine glands: similar to holocrine, but cells do not truly rupture ----can go back if small slit in pm made after everything leaks out so it heals itself

Answer 122

*most abundant & widespread *characteristics: ---*possess an extracellular matrix (ECM) ------ECM- nonliving matrix that separated living cells of tissue *origin: All connective tissue comes from embryonic tissue called mesenchyme

Answer 123

4 classes: -1) Connective Tissue proper -2)Cartilage -3) Bone -4) Blood Major Functions: *Support *Protection *Insulation *Storage *Transport

Answer 124

*Full space surrounding cells & contains fiber -Made of: 1) Interstitial fluid(ISF): allows nutrients to pass from blood --> cells 2) Cell adhesion protecting proteins acting like "glue"to hold living cells to ECM 3) Proteogylcans: give ground substances its consistency --consists of protein core w/ polysaccharide attachment --More proteoglycans = more viscous grand substances

Answer 125

Support structure of Connective Tissue

Answer 126

*Thick pink bands *strong, flexible *resist pulling forces (mechanical stress) *contains protein collagen *found in skin, muscle, bones, tendons, ligaments *Assemble & cross-link w/ other collagen fibers spontaniously

Answer 127

*Branching Networks *Long and thin *Contains elastin protein (body's rubber band) --easily stretch & return to normal shape after stretch removed & prevents parts of body from being stretch out (EX: lungs; inhale & exhale) --higher density in areas of body that are subjected to frequent stretching

Answer 128

*Shorter and finer *Extendinsibly branched to form networks *Continuous w/ collagen fibers - help connect & hold parts of body (support) *higher density in body areas in body where connective tissue attaches to another tissue

Answer 129

*genetic disorder that affects bodys c.t. *mutates in FBN1 gene, which codes production of fibrillin. It contributes to strength & elasticity of c.t. fibers *causes elastic fibers of connective tissue to lose flexibility and strength *Since c.t. is widespread in body shape, those affected have several body system affected --Bones/joints-gangly, thin, long toes/fingers --Heart/blood vessels-enlarged aortas & body has thinner cells --respiratory tract --Eyes-free flowing lense

Answer 130

*Cells found in c.t can be immature cells (-blast) or mature cells (-cyte) --"Blast" cells actively miotic, lay down ground substances/fibers** ----Ex: osteoblast cells in bone tissue ----"immature" produces more cells & produce/release grown substance --"Cyte" cells maintain what is/was laid down by -blast cells ----Ex: osteocyte cells in bone tissue ----"mature"- maintain fibers around

Answer 131

any connective tissue that is not bone, cartilage, or blood

Answer 132

*Areolar connective tissue (most common) -chief cell type = fibroblast -ground substance is thick (lot of proteoglycans when contributes to g.s consistency) -White blood cells can monitor through easily, immune system can use & get through -store stuff (water, Ions) * Adipose tissue (fat tissue) --Function, easy access energy/nutrient source --chief cell type is adipocyte --limited matrix --white space + triglycerides - shows nucleus to side of cell -- more body fat % = more triglycerides --excessive adipose tissue impairs organs *Reticular connective Tissue --forms stroma to support free blood cells in lymph nodes, spleen & bone marrow --not so wide spread - found where blood cells need to be held in place

Answer 133

*Dense Regular ct --Chief tissue type = fibroblast --collagen fibers run in same direction - higher resistance to tension however it can only be pulled in 1 direction (left/right) -Little ground substance -Location: found in tendons, aponeuroses, and ligaments *Dense Irregular ct --collagen fibers are thicker than dense regular; irregular arrangement of fibers -can withstand tension, and can be pulled in mutliple directions w/ less risk of breaking -Ex: skin *Elastic ct -Vary elastic-tissue recoils after stretch -return to og size & shape -found in long walls

Answer 134

*Composed of chondroblasts/chondrocytes *flexible, but still tough (stiffer type) *Avascular; no blood supply, no innervation *get what they need from diffusion-thin sheet *ground substance is very thick/firm ---still cintains large number of water 3 types: * Hyaline cartilage (A) * Elastic cartilage (B) * Fibrocartilage (C)

Answer 135

*found in bone --> tissue contains inorganic calcium salts that make it rigid *Contains osteoblasts and osteocytes --Bone salts deposited on/ within fibers *Highly vascularized, innervated *if blood cell produced in bone/bone marrow, need cells to let blood flow in

Answer 136

*develops from mesenchyme, cellular portion is blood cells, fluid matrix-plasma --most cells are erythrocytes *Fibers form only during blood clotting --> only form when blood vessels broken otherwise soluble in healthy blood vessels *doesn't provide support or physically connect tissue to another -- function: transport nutrients, waste, gases, etc.

Answer 137

*simple organs of human body *3 types: 1) Cutaneous (skin) --compose of keratinized stratified squamous epithelia-makes skin tougher --dry membrane-defense mechanism to prevent infection 2)Mucous membrane (mucosa) --Lines body cavity that lead in/out of body --Ex: mouth & epithelial tissue that lines digestive tract --wet/moist membrane --Epithelial cells attach to lamina propria (areolar ct) --function: absorption/secretion 3) Sereus Membrane (serosa) --line body cavities that closed to outside body --serous membrane maned according to what cavity they are in/ what they cling to --serous fluid produced & secreted by cells in serous membrane

Answer 138

*Response to invasion/injury = inflammatory or immune *Cells in & around injury site must divide & migrate in order for repair to take place ---repair can be regeneration or fibrosis -----*simple infection--> tissue regeneration -----*Severe infection--> scar tissue formation, clotting Steps: 1)Inflammation sets stage by releasing inflammation chemicals 2) organization restores blood supply-Increase in blood supply on skin from granulation tissue 3) Regeneration & fibrosis effect permanent repair

Answer 139

*Cancer is unregulated division of cells in body --results in mass of cells called a neoplasn--> benign or malignant ----malignant forms can become metastatic (can break free from tumor, implant in another tissue and cause 2nd tumor-due to genetic mutation) *primary cause of cancer is mutation in DNA that alters expression genes -Mutations --oncogenes (don't regulate cells division--tumor genes) vs proto-oncogenes (normal genes) --tumor suppression genes *most common forms: skin, colon, lungs, breast, prostate *Treatment-chemo & radiation

Answer 140

A) Chemical: -salts & oily secretion kills bacteria -melanin prevents damage caused by UV light. Dark colors absorb UV * protect DNA in cells from mutating B) physical: -skin prevents entrance of bacteria C) Biological -Dendritic cells patrol dermis to strop anything that passes through epidermis -macrophages destroy large sized "invaders" --can help clear out solid debris

Answer 141

*Insensible perspiartion: unnoticeable sweat loss during the day --sitting doing nothing. Makes tiny tweaks & changes *Sensible perspiration: noticeable sweat loss occurs when excess heat needs to be lost from body --when envi is too hot --physical exercise *when envi temps is cold, blood vessles in skin constrict --> pull blood away from skin --blood = mostly water, water absorbs body heat --heat goes from hight to low *Envi temp increases, flush skin w/ blood to prevent dramatic increase in visceral organ temp. body temp.

Answer 142

*Exteroceptors: Cutaneous sensory receptor -respond to external.outside the body stimuli -can be nociceptors, thermoreceptors, mechanoreceptors (touch, pressure)

Answer 143

*Involved in Vitamin D production --necessary for calcium to be absorbed from the digestive tract

Answer 144

*~5% of blood volume can be found in integument *can be "moved" by CNS

Answer 145

*Sweat allows for some elimination of certain nitrogenous waste (urea, ammonia, uric acid)

Answer 146

1) Epidermis *Unvascularized outermost portion *Stratisfied squaous epatehlia *Epithelia = avascular-no blood supply 2) Dermis *vascularized *much thicker *connective tissue *makes up most of integument by mass -adopose tissue-hypodermis below it Hypodermis (Not true integument) -Lies deep to dermis -Composed of adipose tissue -1) storage: easy to access energy source of body -2)protection/shock absorption: prevents physical trauma to internal organs -3) Insulation: prevents excessive heat loss -4)Anchor: hold skin to underlying muscle tissue

Answer 147

1) Keratinocytes: produce keratin (dry protein) --linked by desmosomes --increase in numbers - most common --reproduce mitotically in response to epidermis growth factor ----reproduces from bottom up. ----Millions of cells lost/daywe ”grow” a completely 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 melansomes --produce melting pigment, which is transfered to keratinoytes ------melanin migrates to "sunny side" of keratinocyte *found deeper in epidermis *brownish cells = karatinocyte 3) Dendritic cell (Langerhans cells) * Move to epidermis from bone marrow * “Presenting” cells-->help to activate the immune system --attatch themselves to pathogen then travel to parts of body w/ immune system cell to notify white blood cells that they can destroy pathogen 4) Tactile Cell (Merkle Cells) * Present in epidermal-dermal junction * Associated with nerve endings--> sensory receptor function

Answer 148

1) Stratum basare (base layer)-innermost layer -simple layer of stem cells attached to dermis ---rapid division of cells here -composed of mostly Keratinocytes ---10-25% cells are melanocytes 2) Stratum spinosum (Spiny layer) -stratified layer -cells contain pre-keratin protein--> thick bundles of filaments that resist tension -dendritic cells most abundant here 3) Stratum granulosum (granular layer) -Keratinization begins here -Accumulation of 2 granule types: ----Keratokyaline: helps w/ formation of keratin in upper layer of epidermis ----Lammelar granules: contain water-resistant glycolipid -cells here are tough & water resistant 4) Stratum lucidum (clear layer) -Cells at this layer are not living ---diffusion only works so far too much distance to cover for diffusion to occur -not found in thin skin (lips, tips of finger_-more sensitive 5)Stratum corneum (horny layer): outermost layer - Cells here are not living -Makes up most of epidermal thickness -Glycolipids between cells help to waterproof this layer -Keratin inside cells protects from friction/abrasion

Answer 149

*The "hide" of the body (leather) *made up of strong & flexible connective tissue (dense, irregular) --fibroblast & microphages dominate here --semifluid matrix --fibers abundant here

Answer 150

Thin areolar connective tissue * Fibers are thin so defensive cells can wander freely here * Has projections called dermal papillae * Can have pain receptors or tactile corpuscles * Projections indent the overlying epidermisforms friction ridges * Genetically determined feature *finger prints

Answer 151

*Lies deep to papillary dermis * Composed of dense irregular connective tissue * Forms cleavage lines in skin * Not visible externally * Lines formed by alternating dense & less dense regions of fibers --surgeons cut parallel to change lines to not to snip fibers * Forms flexure lines at/near joints * Dermis is tightly anchored at the flexure line—does not move as easily * Dermis is forced to fold, forming creases that are externally visible

Answer 152

3 pigments help determine color 1) melanin: polymer that comes in two forms (reddish yellow, brownish black) * Synthesized in cell by protein called tyrosinase * Skin pigmentations dependent on amount of melanin produced by melanocytes * DNA in cells is damaged by sun * Exposure to sun-->DNA in cells is damaged by sun, repair is first “signal” to produce melanin 2) Carotene: yellow-orange pigment * Accumulates in stratum corneum & 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 dermis

Answer 153

* Skin color can be affected by genetics, diet, drugs, illness, etc. * Illness: Jaundice (liver failure) * Genetic: Albinism/melanism (genetic mutations) * Illness: Cyanosis (hemoglobin) * Drugs: Argyria (silver)

Answer 154

Structures that grow and associated w/ Skin

Answer 155

* Grow from follicles Two regions of a hair: * 1) Root: part of hair embedded in skin * 2) Shaft: part of hair projecting out of skin Functions: * 1) Sensory structures: nerves associated with hair follicles * 2) Protection: scalp, eyes, nose * Consist of dead, hard-keratinized cells * Each hair has 3 layers: * A) Medulla: central core composed of large cells and air space --Absent in fine hairs of body * B) Cortex: several layers of flattened cells * C) Cuticle: outermost layer that is most heavily keratinized --Cells in layer are stacked like roof shingles--> prevents hair from sticking together --flat & slightly overlap one another --would form mats w/o stacking like shingles

Answer 156

A) Hair follicle: Results from fold extending from epidermal surface into dermis * Each follicle is composed of 3 layers: * 1) Peripheral sheath: outermost layer composed of dermis * 2) Glassy membrane: ”basement membrane” joining the peripheral sheath to the root sheath * 3) Root sheath: innermost layer derived from epidermis B) Root hair plexus found at base of hair follicle (hair bulb) * Contain nerve endings * allows us to know something on skin w/o looking at it * C) Dermal papilla provides capillaries to hair follicle * D) Arrector pili: smooth muscle cells attached to hair follicle * Contraction pulls hair follicle upright *gives us goose bumps *In animals its a defense mechanism

Answer 157

Shape of hair is dependent on hair follicle shape at skin surface: * Round = straight hair * Oval = wavy/slightly curly * Flattened = very curly/coiled * Color depends on melanin deposition to cortex 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

Answer 158

Hair Growth * Hair matrix composed of rapidly dividing cells from hair bulb of the hair follicle * New cells push old cells up and out * Most growth is cyclical: ----1) grow-laying doen nerve cells and growth occurs ----2) resting phase-nonactive hair matrix-just sitting there ----3) shedding pahse Types of Hair: * 1) Vellus hair: thin/fine hairs * 2) Terminal hair: thick/coarse hairs * Typically darker in color than fine hairs

Answer 159

* 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-->hairs become vellus, many are shed before emerging from the follicle * X chromosomes have genes for hair growth *female less prone to true baldness *no buffer from males *inherited from maternal side

Answer 160

*Found in distal portion of fingers & toes *contain hard Keratin (toughest structure) *composed of root (underneath skin), nail plate, free edge (white rim) *Nail matrix responsible for nail growth--? lays down for growth of new nail *Functions: protective covering fro distal portion of fingers & toes contributes to dexterity

Answer 161

*Cells in sweat glands are myoepithelial cells ---Specialized cells that will contract when stimulated * Secretory cells pull materials needed to produce sweat from blood * Mostly water, but also contains salts, metabolic wastes, etc. * Two types: (both merocrine in mode of secretion) * A) Eccrine glands * B) Apocrine Glands * where you begin to sweat depends on the circumstance

Answer 162

*Especially abundant on palms, soles of feet, forehead --more numerous of the 2 types * Simple tubular glands that open directly to skin surface at a pore * Sweat is mostly water * Function: body temperature regulation

Answer 163

located in axillary and anogenital areas * Empty into hair follicles, then released to skin * Same components as sweat from eccrine glands BUT has some fatty substances and proteins * But also has some fatty substances & proteins *Function: involved in emotional sweating due to stress, fear, pain, and sexual stimulation. *worse at armpit *modified version of this gland include ceruminous(earwax) gland & mammary glands (production of milk)

Answer 164

*Secretes sebum (oily substance) --Sebum is largely lipid-based with some cell components *The growing hair pulls the sebum up and onto the surface of the skin. * Functions: --Lubricant for skin/hair --Slows water loss from epidermal surface --Kills bacteria

Answer 165

* Skin exposed to excess amounts of UV light over time may have some cells become cancerous * This is *the* most common type of cancer * In US-->9,500 diagnosed with skin cancer **per day**

Answer 166

*Most common form, but least malignant --slow growing, metastasis rarely occurs --cells in stratum basal proliferate --found mostly on face, often colorless w/ "rolled" edges

Answer 167

*second common --fast growing --usually metastasizes if left untreated *Cancer of Keratinocytes of stratum spinosum *Appears as scaly, red lesion *found mostly on head & hands

Answer 168

*lowest amount of overall skin cancer cases, but causes the most deaths --metastasizes quickly & can be chemo-resistant *Cancer of melanocytes --can occur spontaneously --1/3 of cases come from pre-existing moles *Early detection = Key -- ABCD(E) rule -Asymmetry -Border -Color -Diameter -Evolving

Answer 169

* 1) 1st degree burn: painful, reddened skin, inflammation --No scarring/fibrosis involved in healing --Ex: sunburn * 2) 2nd degree burn: pain, redness, fluid-filled pouches (blisters) --Takes longer to heal than 1st degree burn --No scarring/fibrosis --Ex: sunburn, mild heat exposure, sometimes radiation * 3) 3rd degree burn: full thickness burns --Treatment usually requires IV fluids, skin grafts, heavy antibiotic use --Fibrosis occurs during healing of burns --Ex: extreme heat, severe chemical/radiation exposure --need to be pumped with fluids and calories if this occurs, especially at a high degree on body.

Answer 170

1) Support --holds up body --cradles organs 2)Protection --Central Nervous system ----skull protects brain ----vertebrae wrap around spinal cord --Visceral organs -----Rib cage wraps around organs in thorax & upper abdominal cavity 3) Attachment point --Skeletal muscle attaches to bone via tendons 4) storage --minerals --fat 5) blood cell formation --hematopoiesis--> formation of blood cells in red bone marrow 6) Hormone production --Osteocalcin--> regulated insulin, release, glucose hormones, & energy expenditure

Answer 171

Before the osseous skeleton forms in an embryo, the skeleton is composed of cartilage and connective tissue fibers

Answer 172

1) Strength & resilience * Cartilage can be compressed & return to original shape 2) Cartilage is mostly water * Contributes to flexibility 3) No nerve supply & is avascular 4) Surrounded externally by fibrous connective tissue called perichondrium * Contains blood vessels * Resists outward expansion of cartilage

Answer 173

* Chief cell type is chondrocyte 1) Hyaline: most abundant type * Chondrocytes are spherical * Contain collagen fibers * Examples: Articular cartilage, costal cartilage, respiratory cartilage, nasal cartilage *prevents lung from collapsing 2) Elastic * Similar to hyaline, but contains more elastic fibers * Examples: External ear, epiglottis *prevents food and liquid into lungs 3) Fibrocartilage * Contain rows of chondrocytes alternating with thick collagen bands * Most compressible, great tensile strength * Examples: Vertebral discs, knee, pubic symphysis *Can hold lots of weight -prevent discs rubbing against e/o -Knee wrapped in fibrocartilage bc lots of pressure on knee

Answer 174

1) Appositional: laying down new cartilage on old cartilage * Cells just under perichondrium deposit new matrix on top of “old” cartilage *Laying down brick * Occurs at surface of cartilage tissue *growth in width/thickness 2)Interstitial: "growth from within" *cells divide & secrete matrix in pre-existing cartilage *increased volume/ Length *occurs throughout cartilage tissue

Answer 175

1) Location * Axial skeleton: makes up long axis of body ----Skull, vertebral column, & ribs * Appendicular skeleton: makes up limbs (aka appendages) of body & the girdles ---Pectoral & pelvic girdles, arms & legs 2) Shape of Bone A) Long bones: longer than they are wide *Example: almost all limb bones B) Short bones: cube-shaped * Examples: bones in wrists & ankles * Sesamoid bones: bone that forms in a tendon --reduce tension/pressure on tendon --patella C) Flat bones: thin, flat, curved * Examples: sternum, scapulae, ribs, most cranial bones D) Irregular bones: anything that does not fit in an above category *Ex: Vertebrae, os coxa

Answer 176

All bones contain an outer layer of compact bone and an inner layer of spongy bone * Compact bonelooks smooth and solid * Spongy (trabecular) bonehas open spaces with needle-like pieces of bone called trabeculae --Open space is filled with red marrow or yellow marrow --Trabeculae found in greatest concentration along lines of stress -----pushed on more often (bear more weight)

Answer 177

* Thin plate of spongy bone covered by compact bone * No well-defined large cavities for bone marrow --All bone marrow found around trabeculae of spongy bone * Covered externally by bone membrane called periosteum

Answer 178

1) Diaphysis: bone shaft * Composed of compact bone “collar” with internal medullary cavity * Medullary cavity filled with yellow marrow in adults 2) Epiphysis: bone ends * Composed of compact bone externally, spongy bone internally * Forms joint surfaces-->ends are covered with hyaline cartilage --no periosteum 3) Membranes: periosteum & endosteum * Periosteum covers external bone surface, except at joints --Double-layeredoutermost layer is fibrous, inner layer composed of osteoprogenitor cells --Very well vascularized and innervated --External surface * Endosteum covers internal bone surface-->trabeculae in spongy bone, cavities in compact bone * Also contains osteoprogenitor cell 4) Vascularization & innervation * Nutrient artery and nutrient vein serve diaphysis * Epiphyseal artery and epiphyseal vein serve epiphyses * Nerves travel with blood vessels

Answer 179

Osteon: structural unit of compact bone * Function: help bone withstand pressure/stress * A single osteon is composed of several layers (called lamella) packed closely together * Collagen fibers run in one direction for a single lamella * Fibers always run in opposite directions in adjacent lamella ---arrangement reduced stress & don't ;et fibers twist easily and break bones * Bone salts found on and in between fibers ---calcium-salts stuck to fibers & make them more rigid * Central canals run through center of each osteon --Canal contains nerve and blood vessels --Perforating canals connect nerve/blood supply of marrow cavity to central canal * Interstitial lamellae: incomplete lamellae found in between complete osteons --Function: Fill gaps between osteons * Circumferential lamellae: found just deep to periosteum --Extend completely around circumference of diaphysis --Function: Resists twisting of long bone

Answer 180

* Found in both long bones and flat/irregular bones ---Flat/irregular bones: marrow found between trabeculae --Long bones: marrow found in marrow cavity of diaphysis * Red bone marrow (hematopoietic tissue) --In infants-->found in all spongy bone & marrow cavities of all diaphyses --In adultsfound around trabeculae of bones of skull, ribs, hips, sternum, clavicles, scapula, vertebrae, heads of femur and humerus --converts to yellow at end of growth (adult) * Yellow marrow** --In adultsfound in diaphysis of long bones --Contains more fat & less blood supply than red marrow --Can be converted back to red marrow -----severe hemorrhage--> yellow goes to red -----anemia

Answer 181

1) Osteoprogenitor (osteogenic) cells * Stem Cells * Mitotically active cells --Can remain as osteogenic cells or differentiate to form osteoblasts 2) Osteoblasts: bone-forming cells * Secrete unmineralized matrix (osteoid) that forms bone tissue * Activity of cell depends on shape --Cube-shaped: secreting matrix --Flattened/squamous: inactive * Only secrete matrix until surrounded 3) Osteocytes: mature bone cell * Monitor and maintain bone matrix * Osteocytes respond to: --Mechanical stress on bone -----Ex: weightlessness, bone loading --Chemical signals -----Ex: calcium levels in bone * Often have several projections of membrane surface 4) Osteoclasts: bone-degrading cells * Portion of cell contacts bone directly * Osteoclast cells produce degrading enzyme --Enzyme collagenase breaks down bone * Functions: --Maintains, repairs, and remodels bones --Important function in blood calcium homeostasis

Answer 182

Organic * Cells and osteoid * Sacrificial bonds in or between collagen molecules stretch & break easily Inorganic * Mineral salts-->mostly calcium phosphate packed around collagen fibers

Answer 183

Osteomalacia (adults) & Ricket’s (children) * Less mineral salts deposited in bone--> bone is weak/soft * Caused by: insufficient calcium in diet, vitamin D deficiency

Answer 184

There are two types of bone ossification: endochondral & intramembranous 1) Endochondral ossification * Formation of ossified bone by replacement of cartilage with bone tissue * Occurs in most bones below the skull * Hyaline cartilage used as a “blueprint” to form ossified bone --Remember: the early embryonic skeleton is made up of cartilage --As ossified bone is laid down, hyaline cartilage is broken 2) Intramembranous ossification: formation of bone from a fibrous membrane * Forms cranial bones of skull, clavicles (flat bones)

Answer 185

Step 1: Formation of a bone collar * Cells of perichondrium specialize into osteoblasts --Perichondrium replaced with periosteum * Osteoblasts lay down bone matrix against cartilage surface --bone collar forms around diaphysis of hyaline cartilage model * Formation of primary ossification center (POC) occurs after bone collar formation * POC is rigid & tough on outside *clump of hardened cells Step 2: Cavity forms in diaphysis center * Cartilage inside POC is calcified --Cells inside ossification center dies off ----matrix maintained by cells; no cells = nothing maintains, so it dies off * Matrix inside POC deteriorates * This creates a cavity inside the diaphysis * Cartilage outside cavity continues to grow-->elongates bone --without collar, the diaphysis would collapse-holds it in place Step 3: Formation of initial spongy bone in diaphysis * Periosteal bud invades cavity --Bud contains nutrient artery/vein, nerve fibers, red marrow elements, osteoprogenitor cells, osteoclasts --Osteoblasts secrete matrix around calcified cartilage inside cavity formed in step 2 -----Initial formation of spongy bone is bone-covered cartilage trabeculae -----Immature spongy bone bc needs to be remodeled Step 4: Formation of medullary (marrow) cavity & elongation of diaphysis * Initial spongy bone from step 3 broken down by osteoclasts * This forms the medullary cavity * Cartilage in diaphysis is calcified, broken down, replaced * Ossification “chases” cartilage formation Step 5: Secondary ossification begins in epiphyses * Steps similar to primary ossification * Except: spongy bone is retained in bone ends-->no medullary cavity formed * NOTICE: there are still some areas with actively growing cartilage --epiphyseal plate = important for bone growth

Answer 186

Step 1: Mesenchymal cells in membrane differentiate into osteoblasts to form the ossification center * Ossification center has osteoblasts that lay down osteoid Step 2: Matrix secreted by osteoblasts * Matrix is calcified after it is secreted * Osteoblasts trapped in calcified matrix form osteocytes Step 3: Formation of periosteum and immature spongy bone * Blood vessels invade area of calcified matrix ---Osteoid laid down around blood vessels-->creates trabeculae called “woven bone” * Mesenchyme at external surface of initial bone forms periosteum Step 4: Compact bone replaces some spongy bone, red marrow develops * Trabeculae just deep to periosteum replaced with compact bone * At center, immature spongy bone remodeled to mature spongy bone * Mature spongy bone fills with red marrow

Answer 187

Growth in Length: accomplished by interstitial growth * Occurs at epiphyseal plate --Cartilage plate that is found between the epiphysis and diaphysis of a bone --Active region = actively dividing/laying down matrix (found closer to epiphysis bone end) *overall process of growth in length 1) New cartilage laid down in epiphyseal plate * 2) Cartilage cells at center of epiphyseal plate enlarge, cartilage is calcified * cartilage near epiphyseal plates die off * 3) Calcified cartilage is broken down by osteoclasts & osteoblasts lay down new bone tissue *bone growth continues from infancy through adolescence * At the end of adolescence: --Chondrocytes divide less often ----New cartilage at epiphyseal plate is no longer produced --Replacement of existing cartilage continues-->epiphyseal plates eventually close -----Epiphyseal plate closure complete when bone of diaphysis and bone of epiphysis meet & fuse

Answer 188

accomplished by appositional growth * Occurs at same time as bone lengthening * Overall process of growth in width: 1) Osteoblasts secrete new matrix at the periosteum 2) Osteoclasts break down bone tissue at the endosteum -(have to lay down more bone than what is broken down)

Answer 189

Growth hormone controls activity at the epiphyseal plate *Released by anterior pituitary gland in brain --Hypersecretion of growth hormones--> gigantism --Hyposecretion of growth hormone--> dwarfism Sex Hormones *Estrogens --Causes growth spurt at puberty --In high levels (i.e., adults)induces epiphyseal plate closure --females stop growing at ~18; younger girls get growth spirits 1st/earlier but closes/stops earlier --Cause feminization of certain parts of skeleton * Testosterone: --Cause masculinization of certain parts of skeleton ----pelvic angle is less than 90 degrees ----mandible is thicker --male stops growing at ~21

Answer 190

Bone deposition and resorption(take old bone tissue, break down, recycle) involved in bone remodeling * New bone tissue continuously laid down, old bone tissue resorbed by body * Importance of bone remodeling: 1) Maintenance of Ca2+ homeostasis * Ca2+ is essential for excitability of body cells (especially neurons and muscle cells) * Without Ca2+neurons do not fire & muscle does not contract 2) Bone health * Mechanical/gravitational forces acting on bone tissue drive remodelingstrengthens bone exactly where it is needed

Answer 191

1) Parathyroid hormone (PTH) released in response to decreasing blood Ca2+ levels * Effects of increased PTH release: --1) Number of osteoclasts at bone increases --2) Osteoclasts begin to resorb more bone tissue * Once blood Ca2+ returns to normal, PTH release decreases --Osteoclast number and rate of activity decrease 2) Mechanical stress * Wolff’s Law: Bones are strongest where they are subject to higher pressure or greater stress (aka “bone loading”) * The more stress is placed on a bone or a certain region of a bone: --1) The more trabeculae will be found at the location of loading --2) The thicker the compact bone will be at the location of loading * Ex: Weightlifters vs. non-weightlifters * Ex: Astronauts

Answer 192

* Bone must be reduced (Line bone back up) for repair to begin * Repair proceeds as follows: 1)Hematone forms --> pool of blood resulting from blood vessels (bruises) 2)Fibrocartilaginous cells (body natural splint) forms --> macrophages clean out hematoma & cartilage cells (chondroblasts) come in to form Fibrocartilaginous cells 3) Bony callus forms 4) Bone remodeling occurs --> so it can withstand normal stress you put it through

Exam 1 Flashcards

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