Circulatory System Flashcards
(40 cards)
function of blood
transport:
- move respiratory gases (O2 to tissues, CO2 waste to lungs), nutrients, wastes, hormones, stem cells
protection:
- contains WBCs that destroy microorganisms and cancer cells, and produce antibodies that help fight infections
- platelets clot the blood if vessels have been injured to minimize blood loss.
regulation:
- capillaries help to stabilize fluid distribution in the body
- the blood contributes to optimal pH by buffering acids and bases
- shifts in blood flow regulate body temperature.
plasma
a complex clear, extracellular fluid of water, proteins, nutrients, electrolytes, hormones, and gases
- serum is what remains when solids are removed
- mostly water (92% by weight)
- proteins (most abundant plasma solute): albumin, globulins, and fibrinogen
- nutrients: glucose, amino acids, lactic acid, lipids, and others
- electrolytes: salts of Na, K, Mg, Ca, Cl, and others
- nitrogenous wastes: urea and others
- hormones
- gases: oxygen, carbon dioxide, and nitrogen
proteins in plasma
- albumin: most abundant and acts to transport solutes, buffer pH, and contributes to viscosity and osmolarity
- globulins play roles in transport, clotting, and immunity
- fibrinogen: (precursor of fibrin, a clotting protein) the liver produces all of the major blood proteins except gamma globulins, antibodies which come from plasma cells (descendants of B lymphocytes).
contents of blood
- plasma (55%): clear extracellular fluid (matrix)
- formed elements (45%): liquid connective tissue; cells and cell fragments ; they include erythrocytes (RBCs), platelets (fragments of bone barrow cells), and five kinds of leukocytes (WBCs).
erythrocytes
Function:
- hemoglobin (component of the RBC cytoplasm): transports nearly all of the O2 and some of the CO2 in the blood
Shape:
- discoid cells with a sunken center
- no nucleus, mitochondria, or organelles, but they do have a cytoskeleton of spectrin and actin that reinforces the plasma membrane
7 major formed elements
- erythrocytes: RBCs (transport gases)
- leukocytes (monocytes, lymphocytes, neutrohils, basophils, eosinophils): WBCs (immune responses)
- thrombocytes: platelets (initiates clotting)
formed elements: erythrocytes
- discoid cells with sunken center & no nucleus
- function mainly to transport O2 and CO2
- most abundant formed element
formed elements: monocytes
- 3-8%; nucleus ovoid/kidney shaped
- sparse nonspecific granules
- function to phagocytize
- differentiate into macrophages
- present antigens
WBC
formed elements: lymphocytes
- 25-33%; nucleus ovoid/round
- may be small or large
- function to destroy cancer cells, foreign, viral cells
- initiate an immune response
- secrete antibodies
WBC
formed elements: neutrophils
- 60-70% nucleus usually with 3-5 lobes
- red/violet granules
- function to phagocytize bacteria
- secrete antimicrobials
WBC
formed elements: eosinophils
- 2-4%; nucleus with 2 large lobes, connected by thin strand
- orange/pink granules
- function to phagocytize antigen-antibody complexes, allergens, and inflammatory chemicals, secrete enzymes to weaken & destroy parasites
WBC
formed elements: basophils
- <0.5%; nucleus large & irregular
- coarse, dark granules
- function to secrete histamine and heparin
WBC
formed elements: platelets
- fragments of bone marrow cells
- second most abundant formed element
- no nucleus, but do have other organelles
- function to form clots, dissolve clots, vasoconstrict, attract WBCs, destroy bacteria
hemostasis
“cessation of bleeding”
steps:
1. when a blood vessel is injured, platelets release serotonin, which triggers vasoconstrictor to minimize blood loss
2. the platelets then adhere to the vessel wall and each other, forming a platelet plug
3. the platelets release clotting factors that convert the protein fibrinogen to fibrin. together, the fibrin, platelets, and blood cells form a clot that seals the breach
4. once the leak is sealed, platelets secrete a growth factor that stimulates fibroblasts and smooth muscle to replace the damaged tissue
5. finally, platelets secrete factor XII that leads to the formation of plasmin, a fibrin-digesting enzyme that dissolves the old clot
thrombocytosis
condition in which there are too many platelets, resulting in abnormal clotting; abnormal clotting of an unbroken blood vessel (thrombosis)
B cells
- type of WBC created in the bone marrow for immune protection
- differentiate into plasma cells- secrete antibodies to fight infection
- some may become memory cells (like T cells) to confer long-lasting immunity
histamine
a vasodilator secreted by basophils which increases blood flow to an injured tissue, and makes blood vessels more permeable so that blood components can get in more quickly
white blood cells
types: monocytes, lymphocytes, neutrohils, basophils, eosinophils
function: immune responses
composition of the heart wall
- epicardium: serous memberane; thin outer layer that consists of simple squamous epithelium on top of areolar tissue also includes thick layer of adipose tissue in some places
- myocardium: thick middle layer of the heart; composed of cardiac muscle (cardiomyocytes), coil around the heart in a spiral (vortex pattern) ; also contains connective tissue framework (fibrous skeleton)
- endocardium: thin inner wall lines the interior of the heart and is continuous with inner lining of blood vessels; simple squamous epithelium overlying thin areolar tissue, but no adipose tissue
a drop of blood returning from the big toe would enter the heart through what vessel?
inferior vena cava
coronary arteries
blood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle (LCA & RCA)
left coronary artery (LCA)
travels through the coronary sulcus under the left auricle and divides into two branches: anterior interventricular branch and circumflex branch
- anterior interventricular branch: runs along the anterior interventricular sulcus; it supplies both ventricles and the anterior interventricular septum
- the circumflex branch: continues around the left side in the coronary sulcus and supplies the left atrium and the posterior wall of the left ventricle.
right coronary artery (RCA)
supplies the right atrium sinoatrial node (pacemaker) then continues along the coronary sulcus under the right auricle; gives off two branches: the right marginal branch and the posterior intervertebral branch
coronary circulation
circulation of blood through the coronary blood vessels to deliver oxygen and nutrients to the heart muscle tissue; most variable aspect of cardiac anatomy
