BLOOD CARDIOVASCULAR SYSTEM PART 1

FUNCTIONS of BLOOD  transports substances & maintains homeostasis in the body

Hemo = blood  hemophobia: fear of blood  hemostasis: bleeding is under control  hematocyte: blood cell  hematemesis: vomiting blood  hematuria: bloody urine  hematopoiesis: formation of blood cells

Blood  is a type of CT made up of scattered cells & a liquid matrix

What’s in blood? 1. Cells (45%)  RBCs  WBCs  Platelets (plts) 2. Plasma (55%)  water, a.a., proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, cellular waste

Hematocrit  vol of blood cells in a sample of blood  blood centrifuged then % cells figured  normal levels:  Newborns: 55-68%  10 yr olds: 36-40%  Women: 38-46%  Men: 42-54%

RBCs  erythrocytes, hematocytes, corpuscles  formed in bone marrow  shape: biconcave disc  allows for optimal surface area for diffusion of O 2 & CO 2  5 million/mm3  no nucleus  so no cell division  live about 120 days  then phagocytosed in liver & spleen

RBCs Functions 1. transport O 2 thru out body (lungs  cells)  hemoglobin: (hgb) large protein that O 2 attaches to inside RBC 2. transports CO 2 thru out body (cells  lungs)

Hemoglobin

 oxyhemoglobin: plenty of oxygen being carried in RBCs, blood is bright red  deoxyhemoglobin: not carrying much oxygen, blood is burgundy-red

Iron  critical element needed to make hgb & normal RBCs  most of body’s Fe is in RBCs  in heme portion

Erythropoietin  hormone secreted by kidneys stimulates formation of more RBCs by bone marrow  requires: vit B12 & Folic Acid

White Blood Cells (WBCs)  leukocytes  general function: defend the body against pathogens

White Blood Cells TypeNameFunctionPicture GranulocytesNeutrophils aka PMNs polymorpho- neutrophils very active in phagocyting bacteria & are present in large #s in pus of wounds, most common of all types, normal= 60% of WBCs (granular cytoplasm) Eosinophilsattack parasites, control allergic reactions 2% of WBC count

White Blood Cells typeNameFunctionPicture Granulocytes continued Basophilsproduces heparin (prevents blood clots) & histamines (inflammatory reaction) 1% of WBC Agranulaocytes (lacking granular cytoplasm) Monocytesprecursors of macrophages; 6% of WBC Lymphocytesmain cell of immune system 30% of WBC

Platelets (plts)  thrombocytes  cell fragments formed from megakaryocyte, live ~4 days  help initiate formation of blood clots  release clotting factors

Plasma  92% water  Functions:  transport nutrients, gases, vitamins, hormones  maintain fluid & electrolyte balance  maintains normal pH

Plasma Proteins 1. Albumins  made in liver  maintain osmotic pressure & blood vol. 2. Globulins  α & β, from liver  transport lipids & fat-soluble vitamins 3. Fibrinogen  from liver, largest of plasma proteins  in blood clotting  fibrin

Hemostasis  process of stopping bleeding 1. blood vessel spasm  damaged vessel  smooth muscle to contract  slows or stops blood loss  plts release serotonin (vasoconstrictor) 2. plt plug forms  plts become sticky forming plug over damaged area 3. Coagulation  forms hematoma/fibrinogen  fibrin

Coagulation  when tissue damaged  damaged cells release prothrombin activator (with Ca++)  prothrombin  thrombin  thrombin acts as enzyme to cause fibrinogen  fibrin  fibrin traps plts & RBCs to form hematoma (blood clot w/in vessel)

Coagulation Pathway

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