Pages 22-31 Flashcards
What makes up the caridovascular system?
Heart + all blood vessels
What is the order blood gets pumped through in the body? (vessel level)
Heart –> arteries –> arterioles –> capillaries –> venules –> veins
What does the pulmonary circuit do?
Transports oxygen-poor blood from the heart –> lungs –> heart
What is the systemic circuit?
Carries blood from heart to rest of the body
Mediastinum?
Area between the lungs
Where are the atria?
The upper chambers of the heart
Where are the ventricles?
Lower chambers of the heart and muscular pumps
Fibrous pericardium?
Outer, fibrous, supportive, protective layer that surrounds the heart
Pericardium?
Serous made up of 2 layers
-Parietal layer is deep to the fibrous pericardium
-Visceral layer is the inner layer of the serous membrane
What are the three layers of the heart?
Epicardium-outer layer/visceral pericardium
Myocardium-middle layer/cardiac muscle
Endocardium-inner layer
How does blood get pumped through the heart, lungs, and body?
Systemic circuit –> superior vena cava, inferior vena cava, coronary sinus –> right atrium –> tricuspid valve –> right ventricle –> pulmonary valve –> pulmonary trunk –> pulmonary arteries–> alveolar capillaries –> pulmonary veins –> left atrium –> mitral/bicuspid valve –> left ventricle –> aortic valve –> aorta –> systemic circuit
Coronary arteries?
Supply blood to tissues of the heart
What is the cardiac cycle?
The sequence of events that occurs during a single heartbeat
Systole?
Contraction
Diastole?
relaxation (expansion)
What occurs in atrial systole and ventricular diastole?
Ventricles relaxed –> valve opens –>70% of blood flows in while last 30% is pushed in via atrial systole
What does the heart sounds sound like?
Lubb-dubb
What causes the Lubb-dubb sound of the heart?
The closing of heart valves and the sudden changes in blood flow
What causes the Lubb sound?
1st heart sound
Ventricular systole
Atrioventricular (av) valves closing
What causes the Dubb sound?
2nd heart sound
Ventricular diastole
Pulmonary and aortic semilunar valves closing
What is a heart murmur of a valve?
Abnormal heart sound derived from incomplete closure of cusps of valves
What is a functional syncytium?
A mass of merging cells that function as a unit
What are the two types of syncytium in the heart?
Atrial and ventricular syncytium
What is the order of the cardiac conduction system?
SA node –> atrial syncytium –> junctional fibers –> AV node –> AV bundle –> bundle branches –> purkinje fibers –> ventricular syncytium
What is the primary pacemaker that initiates rhythmic contraction?
Sinoatrial (SA) node
What is an ECG?
EKG/electrocardiogram
A recording of the electrical changes that occur in myocardium during the cardiac cycle
What 4 factors influence heart rate?
Physical exercise
Body temperature
Fight-or-flight
Concentration of K+ and Ca2+ ions
Parasympathetic impulses via ____ ____ ____ heart rate?
Vagus nerve decrease
Sympathetic impulses via ____ ____ ____ heart rate?
Accelerator nerve increase
What provides sensory info in the aorta and carotid artery?
Baroreceptors
What area of the brain is the cardiac control center?
Medulla oblangata
Arteries?
Carry blood away from the ventricles of the heart
Arterioles?
Receive blood from arteries and carry them to capillaries
Capillaries?
Site where substances are exchanged between blood and body cells
Venules?
Take blood from capillaries to veins
Veins?
Recieve blood from venules and carry it back to the atria of the heart
What are the three layers of arteries?
Tunica interna: innermost layer
Tunica media: smooth muscle and elastic tissue
Tunica external: out layer of connective tissue
How does diffusion in capillaries occur?
Lipid-soluble substances diffuse thru the cell membrane (High concentration to low concentration)
Filtration?
Hydrostatic pressure forces molecules through the membrane
Osmosis?
Diffusion of water
Osmotic pressure?
Draws water into capillaries opposing filtration
What occurs at the arteriolar end of a capillary?
Water and other substances leave the capillary because hydrostatic pressure is greater than osmotic pressure
What occurs at the venular end of the capillary?
Water enters the capillary because osmotic pressure is greater than hydrostatic pressure