Blood Vessels PDF

Blood Vessels roadneceler Artery Veins · carries blood away from G...

Blood Vessels roadneceler Artery Veins · carries blood away from G · carries blood towards &7 circuit · oxygenated except pulmonary · deoxygenated except pulmonary circuit 3 layers of Blood Vessel Wall T u n i c a i n t i m a interna · innermost layer intimate contact w/ blood basement membrane : framework of collagen fibers that connects provides tensile this layer to tunica media ; · surrounds lumen resilience , a recoil to vessel Strength, · very thin (1 or 2 cell layers) has few layers of connective tissue , containing elastic fibers · simple squamous epithelium · internal elastic membrane is in this layer in thick arteries ↳ aka endothelium endothelium epithelium that surrounds the lumen of a has only tunica intima simplesquamous · capillaries : T u n i c a m e d i a blood flow & pressure · thick layer for maintaining · middle layer w/ smooth muscle & elastics fibers · lined (sphincters) · external elastic membrane is in this layer Sphincter vessel diameter o t as Sympathetic contracts : striction = & bp & resistance vasomotor nerve bp a resistan see fibers controls these Vasodation: relaxes : T u n i c a e x t e r n a adventifia outer layer an · layer Vessels (aorta in system of tiny · blood vessels found externa contain vasa vasorum · may in larger vessels media intimate  3 Groups of Arteries Elastic Arteries · thick walled w/ large low resistance lumen ↳ aorta & major branches (aka conducting arteries be they conduct blood from D to medium-sized vessels) · in all 3 tunics , but mostly tunica media that expand & recoil as blood is ejected from 97 a ka pressure reservoir ↳ allows for continuous blood flow downstream Muscular Arteries · aka distributing arteries be they deliver blood to skeletal muscles & organs · has thickest tunica media but more smooth muscle · active in vasoconstriction Arterioles · smallest Control · flow into capillary bed via vasodilation & vasoconstriction of smooth muscle resistance · aka arteries be changing diameter changes resistance to blood flow resistance (friction) ↑ while diameter of vessel ↓ cut diameter in 12 = pressure y 4 T (x 16) > z" cm - resistance + -  Capillaries Function : exchange of gases , nutrients , wastes , hormones b/t blood & interstitial fluid process- diffusion & is fast be capillaries are thin continuous capillaries Types * Least leaky Location CNS muscle & Skin : , lungs , , Structure : endothelium layer forms continuous non-porous sheets G aps (intercellular clefts) b/t S endothelium cells ↓ Function : intercellular clefts allows water small , solutes , a lipid-soluble materials to ter diffuse into interstitial Fluid · rs all 2 - too narrow for blood cells a 100d plasma proteins to pass through inENS, epitheliadesareboud · ↑enestrated a Capillary ↑ have restricted permeability EX) choroid plexus of brain , blood vessels surrounding most endocrine organs (hypothalamus , pituitary gland thyroid , glands pineal glands) filtration sites in , , Kidneys Function : pores (fenestrations) allow rapid of h20a solutes exchange b/t blood Plasma & interstitial Fluid Kidneys : Filtration S Liver : absorbs nutrients fenestrated "Window " Sinusoids capillaries * leakiest EX) liver , spleen , bone marrow , adrenal gland solutes large as plasma Function hzo+ : Proteins pass freely but blood & interstitial fluids a in bone marrow : allows newly formed blood cells to enter circulation & in liver cells : allows plasma proteins to enter blood Calbumin & fibrinogen) clotting proteins Capillary: large sheets that drape over organs Capillary beds: interconnected network of vessels ↳ Metarteriole: main vessel that runs straight through the middle of a capillary bed. to other · connects the arteriole at one end of the capillary bed venule at the · ac ts as a vascular shunt Vascular shunt: can close off (vasoconstrict) its side channels so blood bypasses the capillary beds together Pre-capillary sphincters: bloods the beds · can constrict/dilate vessel , directing the flow a volume of entering autonomic control · under sympathetic Veins · classified by Size (smallest largest) venules - medium ve i n s large veins in Veins is /10 compared to arteries · thinner walls be blood pressure · 65 % total blood volume 35 % total blood volume , (blood reservoirs) · expand easily w/ pressure , have high capacitance (expand easily) · accommodate large changes in blood volume prevent blood from back · values thin flaps of tunica intima ; close to flowing down to the limbs Cardiac Output stroke volume CO = HR * SV Blood Flow CO in mL/min mL/min mL heart rate beats/min cardiac output : vol. of blood that circulates through stp vessels/min  Resistance measurement of amount of friction blood encounters w/ vessel walls (in peripheral/systemic circulation) 3 Factors 1 Blood viscosity · blood thickness · ↑ viscosity = thicker blood - ↑ resistance 2 Vessel Total Blood length ↑ resistance ↑ length = 3 Blood Vessel diameter ↓ diameter = ↑ resistance · resistance varies inversely w/4th power (n") of vessel radius · if radius = /2 resistance increases 16x , Blood Flow (f) is proportional to blood pressure gradient (UP) Apt = blood flow speeds up Blood flow (f) is inversely proportional to peripheral resistance (R) R & = blood flow decreases R is important be it's easily changed F = LP/R by changing blood vessel diameter Generation of Blood Pressure Systemic blood flow blood flow & pumping action of a generates a highest in aorta n lowest in arterioles  Arterial Blood Pressure Arterial blood flow 2 Factors E lasticity (compliance/distensibility) of arteries close to b vol. of blood forced into them & any time Pulsatile flow: bp near ; rises & falls w/ each beat Systolic pressure: pressure is used in aorta during ventricular contraction Diastolic pressure: lowest level of aortic pressure when a rest Pulse pressure: difference but systolic a diastolic pressure Mean arterial pressure (MAP): average pressure in arteries during 1 Cardiac cycle pressure Use 1/3 of pulse pressure diastolic pressure + a (mm Hg) BP is determined by total vol. of blood in cardiovascular system ↓ BV = 1 BP proportional ↑ BV = ↑ BP Capillary Blood Pressure Low pressure desired bc : Capillary , · ↑ BP ruptures fragile , thin wall capillaries for · it slows speed at which blood flows through capillaries , allowing more time gas exchange · some pressure is needed to force solutes out of bloodstream into interstitial space  Venous Blood Pressure 3 adaptations (help pump venous blood back to ) Muscular pump : contraction of Skeletal muscles "milks" blood back toward O : values prevent backflow changes during breathing more blood toward o by squeezing ab. Veins as thoracic Respiratory pump : pressure veins expand Sympathetic Venoconstriction : (sympathetic control) smooth muscles constrict , pushing blood back toward o Cardiovascular Center medulla oblongata of brain provides input to c v joints a muscles (p)ropiocepters= physical=joints & muscles Propioceptors : monitor movements of in pressure & stretch in blood Baroceptors : monitor changes vessel walls (B)aroceptors = blood pressure Chemoreceptors : monitor chemical concentrations in blood (CO2 , Ht , 02) (C)hemoreceptors = chemical concentration  Baroceptors Chemoreceptors · located in : · carotid Sinuses : expanded chambers at the base o f located in : internal carotid arteries · aortic arch · aortic arch of neck & thorax · walls of large artery of neck & thorax · walls of large artery cort 3 impulses to the · chemoreceptors transmits cardio acceleratory center , which a · chemoreceptors activate the vasomotor center , which causes reflex vasoconstriction ↑ blood pressure-returns blood to & lungs · Vasomotor center controls blood vessel diameter · makes 2 reflexes Carotid Sinus reflex : monitor ap to ensure enough blood to brain aortic reflex : maintains BP in systemic circuit  Cardiovascular Hormones & Effects Adrenal medulla hormones epinephrine a norepinephrine & coa vasoconstriction ↓ BP BV vasoconstriction & , , , Angiotensin II R Stimulates vasoconstriction ADH ↑ levels can cause vasoconstriction Atrial Natriuretic Peptide (ANP) ↓ BP (by antagonizing aldosterone) , ↓ bv , vasodilation & R  Lymphatic System Function Lymph : fluid in vessels · renamed when excess interstitial fluid enters lymphatic system - drains excess interstitial fluid ↳ Fluid b/t cells (initial lymphatic vessels) (connective tissue) · travels to lymphatic system by lymphatic capillaries · first formed in lymphatic capillaries * transport dietary lipids · ultimately drains to thoracic duct ↑ carries out immune responses Blood capillaries 2 (blood plasma ↑ Subclavian vein (blood plasma) interstitial space ↑ Fluid FlOW (interstitial Fluid) Sequence S thoracic duct (lymph) & lymphatic vessels (lymph) 2 Types of Lymphocytes B lymphocytes (cells) T lymphocytes (cells) for cell-mediated immunity & coordination · responsible · responsible for humoral immunity of immune response activites of other humoral immunity : a defense that involves production cells directly or control · · attack foreign lymphocytes of antibodies viruses figi cancer cells - distributed by blood & lymph > - antibodies attack foreign antigens , bacteria · effective against · activated B-cells = Plasma cells Synthesize & secrete antibodies plasma cells : · antigens for destruction · antibodies : mark ; anything that provoke immune response · antigens : anything your body sees as foreign T lymphocytes Macrophages : phagocytize foreign substances & help activate Dendritic cells : found in skin ; capture antigen o bring them back to lymph nodes "Trap" S  Lymphatic Tissue Functions · houses lymphocytes & allows them to increase rapidly (proliferate) · allows macrophages& lymphocytes an area to look for pathogens Primary lymphoid organ stem cells divide & become Where 1) lymphocyte "trained" immunocompetent > where - lymphocytes learn how to mount an immune response 2 examples (organs Red bone Marrow : Stem cells "give rise" to 2 types of lymphocytes (B + T lymphocytes) a Thymus : where T cells mature , proliferate , become immunocompetent decreases our ability to fight infections as we age Secondary lymphoid organ > - in tissues W here - most immune responses occur mature lymphocytes first meet activated > - where antigens & are ex) spleen , lymph nodes , lymphatic nodules => Primary lymphoid organenter Secondarorgan  Lymph Node Functions · cleanse lymph · act as lymph filters enter y a macrophagesremovedestroymicroorganisms/debris that · immune system activation · offer a place for lymphocytes to become activated & mount an attack against antigens "arrival" lymph enters this side of node Outer cortex contains B cells deeper cortex lacks nodules & has T cells "exit" exits here lymph has B cellsa plasma cells divides lymph node into many parts Spleen ucosa MALT protects pathogens trying to largest lymphoid organ · enter body Red pulp removes a recycles old ba peyer's patches appendix , · ex) tonsils , , sociated connective tissue of respiratory tract · white pulp has lymphatic tissue that has B + T cells · also allows intimate contact b/t blood & in ileum of small intestine Peyer's patches : lymphocytes ymphatic Tonsils · gather a remove pathogens in food/air issue  Immune System Pathogen: any microorganism (bacteria , virus , fungus etc) , that can cause a disease Antigen: something that involves an immune response (antibody generator) born WI Innate (nonspecific) Adaptive (specific) these defense system defense system 1st line of defense epithelium 3rd line of defense Surface barriers Humoral immunity · Skin · B cellS · mucuous membranes immunitya - 2 weeks for body to build immune army cellular · 1st exposure to disease particularforeignSubstance is · attacks 2nd line of defense connective tissue Internal defenses · phagocytes · natural killer cells · inflammation protein a · antimicrobial · inhibit spread of invaders · inflammation-important mechanism · faster · immune system is trained to respond Phagocytes: WBC's that ingesta digest foreign invaders 2 types Neutrophils : most abundant; die fighting ; become phagocytic on exposure to infectious material develop from monocytes Chief phagocytic cells ; most robust phagocytic cell Macrophages : ; · Free macrophages : Wander through tissue spaces mobile patrol ex) alveolar macrophages · Fixed macrophages : permanent residents of some of some organs bouncers ex) Stellate macrophages (liver) guard the door microglia (brain) 5 stages of phagocytosis > phagosattractedtopathogenbychemicalproductsa phagocyte has receptors on its cell sur face that attach to chemicals on membrane sur face of pathogen phagocyte engulfs microbe , surrounding it in a Sac (phagosome) lysosomes within cell fuse with phagosome to form phagolysosome , releasing digestive enzymes (lysozymes) that break down microbial cell wall digestive enzymes kill microbes  WBC Natural Killer(NK) cells: · can kill cancer & virus-infected body cells before the rest of the immune system is enlisted attack any target they consider foreign by reading the · antigens on pathogen's plasma membrane not phagocytic · police lymph a node · · kill by inducing aptosis in cancer virus infected cells & Inflammation: body's way of isolating keep it from spreading · a source of infection & · produces · Redness (t RBC) · Heat (blood- war m , 4 RBCs deliver RBC's to tissue , · SwellingWBRBIt on sensory nerves) STAGES : > - inflammatory chemical release · Chemicals are released to ECF by injured tissues/immune cells ex) histamine released by mast cells dilates blood vessel ↑ & vessel permeability (attracts monocytes/ neutrophils/macrophages) process = positive Chemotaxis : cells follow Chemical gradient) interstitial fluids - emigration of phagocytes to · neutrophils (in early stages) predominate infection a die rapidly monocytes help macrophages engulf damaged tissues · & invading microbes , then die gathering/accumulation of dead cells & fluids = pus > - phagocyte mobilization Interferon · antimicrobial protein viruses (sneaky microbes) replicate inside cells which escapes How they work · , detection from antibodies circulating released virus-infected lymphocytes microphages & by · , , fibroblasts · have indirect role in fighting cancer interferons travel & bind to membrane of nearby healthy cells · a type of Cytokine : chemical messenger that allow cells to coordinate their actions once bounded , healthy cells produces anti-viral proteins in Cytoplasm inter ferons will "interfere" virus replication if they enter cells later on , which prevents disease  Complement system · 20 diff. Plasma proteins in blood ; · When attached or "fixed" the complementary proteins becomes "activated" activation = releases inflammatory chemicals that amplify inflammatory processes complement= enhance actions of innate/adaptive defenses · cause microbes to burst (cytolysis) , promote phagocytosis , a did in inflammation How they work begin as inactive proteins (C) C - Ca When activated , they're split by enzymes into 2 Fragments (a + b) #s activated amplifies & effects on pathogens , promoting phagocytosis , Cytolysis , a inflammation Humoral immunity Cellular immunity · aka antibody-mediated immunity · aka cell-mediated immunity · antibodies float freely in blood & lymph vessels · T-cells cells attack · antibodies bind to extracellular pathogens · intracellular pathogens virus , bacteria > - marks them for destruction by phagocytes/complement , Fungi proteins Haptens Epitope (antigenic determinants) (incomplete antigens) (binding Sites) · Dangerous When combined w/ body's own. · part of antigen that antibody binds to proteins · each epitope induces production of a specific · adaptive immune system may recognize as antibody or activate a T cell foreign & attack ex) anything that causes allergic reaction · > - Poison ivy (toxin : urushiol) > - cosmetics  Clonal Selection forms: ~ lymphocytes divides via mitosis & differentiate (forms · effector cells ex) Plasma cells : attack & antigens specialized cells) in response to an antigen ↑ cells (helper & cytoxic) · memory cells : produce more if effector cells at faster rate returns ha she same antigen ; is - occurs in secondary lymphatic organs & tissues ex) memory B cells helper t cells & helper cytoxic cells Antigen-presenting cells (APC) · naive + cells that can only be activated by antigens w/ MHC proteins by APC 4) matured B + T cells that haven't been exposed to antigen · ex) dendritic cells macrophages B lymphocytes Primary response Secondary response 1. Antigen activate the appropriate B cells. Memory B cells are exposed to the 2. B cells differentiate into plasma cells & memory B same antigen a second time & divides cells. quickly, differentiating into plasma cells 3. Plasma cells secrete antibodies into the that secrete antibodies in large bloodstream: Immunoglobulin M, or IgM (first antibody quantities. to appear) IgG (more effective)  Antibodies (Immunoglobulins) · T-Y-shaped-each arm-antigen-binding site · antigen-binding site t right antigen-antigen-antibody complex · antigens bind to specific portion of antigen (antigenic determinant sites) & Inactivates them epitopes antigen-antibody complex tags antigen for destruction by other components of immune system 1st antibody released by primary immune response secreted by plasma cells How they work Neutralization Agglutination & Precipitation antibody binds to an antigen in a way antibodies bind similar antigens together, that prevents the antigen from causing them to clump or precipitate out of attaching to body cells. This blocks the solution, making them easier to eliminate. harmful effects of the pathogen. Activating the Complement System Attracting Phagocytes When an antibody binds to an antigen, it changes Antigens marked with antibodies attract shape, allowing complement molecules to latch on macrophages who phagocytize the and help destroy the threat.. The complement invaders. In opsonization, antibodies also system works alongside the antibody to weaken make it easier for macrophages to grab and ultimately destroy the pathogen. and engulf pathogens.  T cells I function (TH) · helps see & respond to antigens by binding to MHC-II (TH) - CRUCIAL for Helper T Cells to connect with other immune cells to identify & respond to external threats destroy cells that cells (TC) harbor anything foreign Major Histocompatibility Complex (MHC) located on the plasma membranes of all body cells except rbc not part of your body Function: help T cells recognize that an antigen is foreign MHC-I MHC-II like a “personal ID badge” like a “help signal” that only : every cell in the body wears to antigen-presenting cells show show it’s part of the body’s team. when these cells (macrophages, dendritic cells, B cells) encounter This marker identifies each cell a pathogen, they capture it, as “self” and healthy. process it, and present part of it on their MHC-II. if a cell is infected, it displays a bit of the pathogen on its MHC-I, Then calls Helper T cells over to alerting Cytotoxic T cells to come initiate a full immune response destroy it.