Ann Senisi Scott & Elizabeth Fong: Body Structures & Functions 11 th Edition

Transcription

1 Chapter 12: Bld Thery Lecture Outline Objectives 1. List the imprtant cmpnents f bld 2. Describe the functin f each cmpnent 3. Recgnize the significance f the varius bld types 4. Describe sme disrders f the bld 5. Define the key wrds that relate t this chapter Intrductin The bdy cnsists f active cells that need a cntinuus supply f nutrients and xygen. Metablic waste prducts need t be remved frm the cells t maintain a stable cellular envirnment. Bld is the primary transprt medium that is respnsible fr meeting these cellular demands. A central pump, the heart, prvides the frce t mve the bld thrugh a system f vessels that extend thrughut the bdy. The average adult s bdy has 8-10 pints f bld. Bld Average adult bdy has 8-10 pints f bld Functin f the bld a. Transprt 1. Transprting xygen frm the lungs t the tissues and carbn dixide frm the tissues t lungs 2. Transprting nutrient mlecules (glucse, amin acids, fatty acids and glycerl) frm the small intestine r strage site t the cells f the bdy 3. Transprting waste prducts (lactic acid, urea and creatinine) frm the cells t kidneys and sweat glands fr excretin b. Regulatry 1. Regulates hrmnes and ther chemicals that cntrl the functining f rgans and systems 2. Helps t regulate the bdy ph thrugh buffers and amin acids that it carries; ph f bld is Regulates bdy temperature by circulating excess heat t the bdy surfaces and lungs 4. Regulates the water cntent f cells thrugh its disslved sdium in, thus playing a rle in smsis c. Prtectin 1. Circulates antibdies and defensive cells t cmbat infectin and disease 2. Prduces clts t prevent excessive lss f bld Bld Cmpsitin When a sample f bld is spun in a centrifuge, the cells and cell fragments are separated frm the liquid part f the bld Plasma liquid prtin f bld withut its cellular elements Serum name given t plasma after a bld clt is frmed Cellular elements (frmed elements) a. Erythrcytes r red bld cells b. Leukcytes r white bld cells c. Thrmbcytes r platelets Bld Plasma Straw clred Cmprises abut 55% f the bld vlume Cntains the fllwing 6 substances Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin

2 Water 92% f the ttal vlume f plasma Maintained by the kidneys and by water intake and utput Plasma prteins a. Fibringen necessary fr bld cltting and synthesized in the liver b. Albumin mst abundant f all the plasma prteins prduced in the liver and help t maintain the bld s smtic pressure and vlume c. Glbulin frmed in the liver and the lymphatic system 1. Gamma glbulin helps synthesis f antibdies 2. Prthrmbin helps bld t cagulate with the aid f vitamin K Nutrients glucse, fatty acids, chlesterl and amin acids absrbed frm the digestive tract Electrlytes mst abundant electrlytes are sdium chlride and ptassium chlride Hrmnes, vitamins, and enzymes fund in small amunts and help cntrl chemical reactins in the bdy Metablic waste prducts all bdy cells are actively engaged in chemical reactins t maintain hmestasis and as a result waste prducts are frmed and subsequently carried t varius excretry rgans Frmatin f Bld Cells Red Bld Cells (RBCs) Hematpiesis is the frmatin f all bld cells a. Occurs in the red bne marrw b. Certain lymphatic tissue prduces sme white bld cells (i.e. spleen, tnsils and lymph ndes) c. Develp frm stem cells undifferentiated precursr cells r hematcytblasts Erythrpiesis a. The manufacture f red bld cells (RBCs) ccurs in the Red bne marrw f essentially all bnes 1. Erythrcytes cme frm stem cells in the red bne marrw called hemcytblasts 2. As the hemcytblast matures int an erythrcyte, it lses its nucleus and cytplasmic rganelles 3. The hemcytblast als becmes smaller, gains hemglbin and develps a bicncave shape b. RBCs live abut 120 days During this time they travel thusands f miles as they circulate thrughut the bdy. Nrmally the erythrcytes have a flexible cell membrane that allws them t bend and squeeze thrugh the capillaries. As they age, hwever, their membrane lses its elasticity and becmes fragile. When they are defective r wrn ut, macrphages, which are phagcytic cells in the spleen and liver, remve them frm circulatin, and they are replaced by an equal number f new cells. Under typical cnditins, mre than 2 millin erythrcytes are destryed and replaced every secnd. c. Prcess f develpment and breakdwn When RBCs are destryed, the Hemglbin is separated int its heme and glbin cmpnents. The prtein prtin f the hemglbin in the erythrcyte is brken dwn int its cnstituent amin acids, which are added t the supply f amin acids that are available in the bdy. The heme prtin f the mlecule is brken dwn int an irn cmpund and bilirubin, a yellw bile pigment. The liver then recycles the irn and sends it t the bne marrw fr new hemglbin. Bilirubin becmes part f the bile, which is secreted by the liver, and is carried in the bile duct t the small intestine. d. Nrmal ranges Red Bld Cells 1. Females 4.2 t 5.4 millin/µl 2. Males 4.5 t 6.2 millin/µl Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin

3 Hemglbin Erythrcytes cntain a red pigment called hemglbin Made f prtein mlecule called glbin and an irn cmpund called heme Functin f RBCs Helps t transprt xygen t the tissues and sme carbn dixide away frm the tissues a. Oxyhemglbin xygen carrying erythrcytes b. Carbaminhemglbin ccurs when erythrcytes release xygen int tissues and pick up carbn dixide. The carbn dixide that is frmed in the cells is picked up by the plasma as a bicarbnate; which is respnsible fr the dark, reddish-blue clr characteristic f venus bld Nrmal ranges a. Females g/100ml b. Males g/100ml Hemlysis a rupture r bursting f the red bld cell which smetimes ccurs as a result f a bld transfusin reactin r ther disease prcesses White Bld Cells (WBCs) Called leukcytes Larger than erythrcytes but fewer in number and are manufactured in bth red bne marrw and lymphatic tissue Natural defense against injury and disease This is achieved thrugh: a. Phagcytsis and destructin f bacteria b. Synthesis f antibdy mlecules c. Cleaning up f cellular remnants at the site f inflammatin d. Walling ff f the infected area Even thugh leukcytes are cnsidered t be bld cells, they d mst f their wrk in the tissues; they use the bld as a transprt medium Types f leukcytes Because WBCs are clear and clrless*, they must be stained first with an apprpriate dye usually Wright s stain befre they can be identified under the micrscpe. *lack f hemglbin gives the cell a whitish appearance Classificatin is due t the presence f cytplasmic granules, nuclear structure and reactins t stains (Table 12-3 pg. 245) 1. Granulcytes Cells develp granules in the cytplasm Made in red bne marrw frm cells called myelblasts Mst granulcytes live nly a few days 2. Agranulcytes Thse that d nt have granules Lifespan ranges frm a few days t several years Diapedesis Prcess that allws leukcytes t mve thrugh the capillary walls int the tissue spaces which prvides a defense against rganisms that cause disease Nrmal ranges Average 3,200 t 9,800/µl Types f WBCs Granulcytes Made frm cells called myelblasts Three types a. Neutrphils 1. Phagcytize bacteria with lyssmal enzymes Phagcytsis is a prcess that surrunds, engulfs and digests harmful bacteria Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin

4 2. Mst cmmn type f leukcyte b. Esinphils 1. Phagcytize the remains f antibdy-antigen reactins 2. Increase in number in allergic cnditins (neutralize histamine), malaria and parasite r wrm infestatins c. Basphils 1. Activated during an allergic reactin r inflammatin 2. Prduce histamine, a vasdilatr that increases bld flw t damaged tissues, and heparin, an anticagulant that inhibits bld clt frmatin Types f WBCs Agranulcytes Lymphcytes a. Subdivided int: 1. B-lymphcytes synthesized in the bne marrw 2. T-lymphcytes synthesized in the thymus gland b. Help the bdy by synthesizing and releasing antibdy mlecules and by prtecting against the frmatin f cancer cells Mncytes a. Frmed in bne marrw and the spleen b. Assist in phagcytsis c. During inflammatin, they help t wall ff and islate the infected area Inflammatin Occurs when living tissue is damaged in any way Signs and symptms a. Redness b. Lcal heat c. Swelling d. Pain The inflammatry prcess Figure 12-2 pg. 246 a. Mast cell is irritated causing histamine t be released 1. Increases bld flw and capillary permeability t the injury 2. The damaged area is walled ff as a result f the cltting actin f fibringen n the damaged tissue and macrphage (cell that remves dead rganisms and freign substances by phagcytsis) actin b. Cellular respnse 1. Neutrphils and mncytes are stimulated 2. Neutrphils mve quickly int damaged area by diapedesis 3. Neutrphils begin phagcytsis f the pathgenic micrrganisms 4. Neutrphil death and pus frmatin Pus is a cmbinatin f dead tissue, dead and living bacteria, dead leukcytes and bld plasma 5. Macrphage invasin and cleanup c. Vascular respnse 1. Vasdilatin which leads t hyperemia (increased bld t an area) Capillaries bulge causing redness and heat 2. Vascular permeability endthelial cells spread apart 3. Bld serum and white bld cells leak int tissue causing swelling 4. Increased edema in the tissues puts pressure n nerves causing severe pain 5. Area is prtected, causing lss f functin Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin

5 Thrmbcytes (Bld Platelets) Smallest f the slid cmpnents f bld; thrmbcytes are nt cells but fragments f the megakarycytes cytplasm Functin in the initiatin f the bld-cltting prcess a. When a bld vessel is damaged, the platelets are stimulated t prduce sticky prjecting structures, allwing them t stick t the cllagen fibers b. This reactin ccurs cuntless times, creating a platelet plug t stp the bleeding c. Platelets secrete a chemical called sertin (sertnin) which causes the bld vessel t spasm and narrw and a decrease in bld lss until the clt frms Nrmal ranges 250,000 t 450,00 per cubic millimeter f bld Old platelets eventually disintegrate in the bne marrw Cagulatin Figure 12-3 pg. 248 Bld cltting r cagulatin is a cmplicated and essential prcess which depends in large part n thrmbcytes Injury leads t release f sertnin and thrmbplastin a. Thrmbplastin is a cmplex substance that can nly cause cagulatin if calcium ins and prthrmbin are present b. Prthrmbin is a plasma prtein synthesized in the liver Prthrmbin cnverts t thrmbin Thrmbplastin and calcium ins act as enzymes in a reactin that cnverts prthrmbin int thrmbin Fibringen cnverts t fibrin Clt Thrmbin acts as an enzyme, changing fibringen a plasma prtein int fibrin The fibrin threads layer themselves ver the cut, creating a fine, mesh-like netwrk that entraps the red bld cells, platelets and plasma creating a bld clt Cltting time nrms The cltting time fr humans is frm 5 t 15 minutes Bld Types There are fur majr grups r types f bld: A, B, AB and O Types a. A b. B c. AB d. O Antigens and antibdies a. ABO bld grups are based n the presence f absence f certain antigens n the surface f the RBC membrane b. These antigens, A and B, are inherited; cnsequently, bld types are als inherited 1. Type A bld has type A antigen 2. Type B bld has type B antigen 3. Type AB bld has bth A and B antigens 4. Type O bld has neither type A nr type B antigens c. Certain bld antibdies develp in the plasma shrtly after birth 1. Type A bld develps B antibdies 2. Type B bld develps A antibdies 3. Type AB bld develps neither A r B antibdies 4. Type O bld develps bth A and B antibdies Test knwn as type and crssmatch is dne befre receiving a bld transfusin t determine bld type Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin

6 Agglutinatin a. Antibdies react with the antigens f the same type, causing the red bld cells t clump tgether b. The clumping f bld, a prcess knwn as agglutinatin clgs the bld vessels, impeding circulatin which culd cause death c. Example: Type B bld culd nt receive Type A bld because the Antigen B wuld clump with the B Antibdies f Type A bld Rh factrs a. Human red bld cells, in additin t cntaining antigens A and B, als cntain the Rh antigen 1. Peple pssessing the Rh factr are said t be Rh psitive Abut 85% f Nrth Americans 2. Peple withut the Rh factr are Rh negative Abut 15% f Nrth Americans b. Nrmally, neither Rh+ nr Rh- individuals have Rh antibdies 1. If an Rh- persn is expsed t Rh+ bld, either thrugh a bld transfusin r by transfer f bld between a mther and fetus, the Rh- individual develps Rh antibdies 2. If that individual is expsed t Rh+ bld a secnd time, a transfusin reactin results (agglutinatin) 3. RHO Gam, a special preparatin f immune glbin, is given t Rh- mthers with Rh+ fetus s within 72 hurs after delivery f each baby Antibdies in RHO Gam destry any Rh+ cells f the baby s which may have entered the mther s bldstream Prevents the mther s immune system frm prducing Rh antibdies Recipient and dnr matching Table 12-4 pg. 249 a. When transfusins are given, it is necessary t match bth the Rh type and the ABO type b. Universal recipient 1. Type AB+ 2. May receive any type f bld Universal dnrs a. Type O Rhb. May dnate t all types f bld Bld Nrms Tests have been devised t use physilgical bld nrms in diagnsing and fllwing the curse f certain diseases Bleeding time 1 t 3 minutes Cagulatin time 5 t 15 minutes Hemglbin cunt a. Female 12 t 16 gm/dl b. Male 14 t 18 gm/dl Platelet cunt 150,000 t 350,000/mm 3 Prthrmbin time a. 9.5 t 11 secnds b. Dsage f medicatin is based n cltting times Sedimentatin rate a. Time required fr erythrcytes t settle t the bttm f an upright tube at rm temperature b. Elevated ESR indicates whether disease is present and is valuable in bserving the prgressin f inflammatry cnditins c. Female 0 t 20 mm/hur d. Male 0 t 10 mm/hur Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin

7 Red bld cell cunt a. Female 4.2 t 5.4 millin/µl b. Male 4.5 t 6.2 millin/µl White bld cell cunt 3,200 t 9,800/µl Chlesterl level belw 200 mg/dl Disrders f the Bld Anemia a. A deficiency in the number and/r percentage f RBCs and the amunt f hemglbin in the bld b. Characterized by varying degrees f dyspnea, pallr, palpitatin and fatigue Irn-deficiency anemia a. Caused by a deficiency f adequate amunts f irn in the diet b. Alleviate cnditin by ingestin f irn supplements and green, leafy vegetables that cntain the mineral irn Pernicius anemia a. Deficiency f vitamin B 12 and/r lack f the intrinsic factr necessary fr the absrptin and utilizatin f vitamin B 12 b. characterized by dyspnea, pallr and fatigue as well as specific neurlgic changes Aplastic anemia Disease caused by the suppressin f the bne marrw Sickle cell anemia a. Chrnic bld disease inherited frm bth parents b. Causes RBCs t frm in the abnrmal crescent shape c. Mst prevalent in African-Americans Cley s anemia (Thalassemia) a. Bld disease caused by a defect in hemglbin frmatin b. There is n natural way fr the bdy t eliminate irn leading t irn verlad and rgan failure Plycythemia a. A cnditin in which t many RBCs are frmed b. Treat with phlebtmy r drug therapy Emblism Where a freign substance (air, clt, cancer cells, fat, bacterial clumps) r emblus is carried by the bldstream until it reaches an artery t small fr passage Thrmbsis Hematma Frmatin f a bld clt r thrmbus in a bld vessel caused by unusually slw bld circulatin, immbility r decrease in mbility Lcalized cltted mass f bld fund in an rgan, tissue r space caused by a traumatic injury Hemphilia Hereditary disease in which the bld clts slwly r abnrmally Thmbcytpenia Bld disease in which there is a decrease in the number f platelets resulting in bld that will nt clt prperly Leukemia Septicemia Cancerus r malignant cnditin in which there is a great increase in the number f white bld cells which replace the erythrcytes, thus interfering with the transprt f xygen t the tissues and hinder the synthesis f new red bld cells frm bne marrw Describes the presence f pathgenic (disease-prducing) rganisms r txins in the bld Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin

8 Multiple myelma Cnditin where plasma cells r B-lymphcytes multiply abnrmally in the bne marrw, causing weakness in the bne leading t pathlgic fractures and bne pain Bne Marrw Transplants A prcedure that transplants healthy bne marrw int a patient whse bne marrw is nt functining prperly Used t treat leukemia, aplastic anemia, sickle cell anemia and t replace the bne marrw and restre nrmal functin after high dses f radiatin that are given t treat malignancies Different types f bne marrw transplants: a. Autlgus bne marrw transplant The dnr is the patient him/herself b. Allgenic bne marrw transplant Dnr shares the same genetic type as the patient 1. Identical twin 2. Parent 3. Unrelated 4. Umbilical crd Bne marrw transplant prcedure a. High dses f chemtherapy r radiatin are included in the preparatin t effectively treat a malignancy and make rm in the bne marrw fr new cells t grw Therapy is called ablative because it stps the prcess f bld cell prductin and the marrw becmes empty b. Marrw transplant is administered thrugh a central venus catheter c. The stem cells find their way int the bne marrw and reprduce healthy new cells Engraftment Perid f time fllwing the transplant Marrw begins reprducing new bld cells, usually between the 15 and 30 th day Ann Senisi Sctt & Elizabeth Fng: Bdy Structures & Functins 11 th Editin