BloodCardiovascular System - 1

for student copying

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 O2 & CO2

• 5 million/mm3• no nucleus– so no cell division

• live about 120 days– then phagocytosed in liver & spleen

RBCs Functions

1. transport O2 thru out body (lungs cells)– hemoglobin: (hgb) large protein that O2

attaches to inside RBC

2. transports CO2 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 CellsType Name Function Picture

Granulocytes Neutrophils aka

PMNspolymorpho-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)

Eosinophils attack parasites, control allergic reactions2% of WBC count

White Blood Cellstype Name Function Picture

Granulocytes continued

Basophils produces heparin (prevents blood clots) &

histamines (inflammatory reaction)

1% of WBCAgranulaocytes (lacking granular cytoplasm)

Monocytes precursors of macrophages;

6% of WBC

Lymphocytes main 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 Proteins1. 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 bleeding1. 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)