Anatomy of the Cardiovascular System Flashcards
Cardiovascular system
Transports fluids, nutrients, waste products, gases, hormones
Exchanges materials between blood, cells, extracellular fluid
- immune response, blood pressure, regulation of body temperature
Heart, blood vessels, capillary beds, blood
Function of the Heart
- generates blood pressure by moving blood through vessels
- Routing blood: separates pulmonary and systemic circulations
- Ensures one-way blood flow
- Regulates blood supply
- Changes to match need
Location of the heart
thoracic cavity in mediastinum
Characteristics of the heart
- size of a closed fist
Apex - blunt rounded point of cone
Base - flat part at opposite end
Pericardium
Fibrous and serious pericardium
Fibrous pericardium
tough fibrous outer layer
Serous pericardium
thin, transparent, inner layer, simple squamous epithelium
Heart Wall
- Epicardium
- Myocardium
- Endocardium
Epicardium
Serous membrane; smooth outer surface of heart
Myocardium
middle layer composed of cardiac muscle cells - contractability
Endocardium
smooth inner surface of heart chambers
Pectinate muscles
muscular ridges in auricles and right atrial wall
Trabeculae muscles
muscular ridges and columns on inside walls of ventricles
Right atrium
three major openings to receive blood returning from the body
Left atrium
four openings that receive blood from pulmonary veins
Atrioventricular canals
openings between atria and respective ventricles
Right ventricle
opens to pulmonary trunk
Left ventricle
opens to aorta; very muscular wall
Interventricular septum
between two ventricles
Great vessels: into heart
Right atrium - superior, inferior vena cava
Left atrium - left, right pulmonary veins
Great vessels; out of heart
Right ventricle - pulmonary trunk
Left ventricle - aorta
Atrioventricular valves
Cusps attached to papillary muscles by chordae tendineae Right - tricuspid Left - bicuspid - valve open: blood flows A to V - valve closed: blood exits ventricle
Semi-lunar valves
Right - pulmonary
Left - aortic
Valve closes when cusps are filled - stops backflow
Valves are open when cusps are empty - blood exits the heart
Arteries
elastic, muscular, aterioles
Take blood away from the heart
Contain blood under pressure
Capillaries
site of exchange with tissues (interstitial fluid)
Veins
large, medium, small, venules
Takes blood to the heart
Thinner walls than arteries, contain less elastic tissue, less smooth muscle
Valves to prevent backflow
Tunica intima
endothelium
Tunica media
smooth muscle cells arranged circularly around the blood vessel
- vasoconstriction: smooth muscle contract, decrease in blood flow
- vasodilation: smooth muscles relax, increase in blood flow
Tunica externa (adventitia)
connective tissue
Capillaries
Capillary beds - extensive networks for exchange
Wall consists of endothelial cells (simple squamous), basement membrane and delicate layer of C.T
Substances move through by diffusion
Functions of blood
Transport - gases, nutrients, waste products, processed molecules, hormones, enzymes pH and osmosis regulation (pH 7.4) Maintenance of body temperature Protection against foreign substances Clot formation
Red Blood Cells
- No nucleus and biconcave shape to increase SA (oxygen carrying capacity)
- Oxygen - 98.5% haemoglobin, 1.5% dissolved in plasma
