Overview & Anatomy Flashcards
What are the functions of the CV system?
- distributes dissolved gases & nutrients.
- removes metabolic waste
- contributes to systemic homeostasis (controlling temp, O2 supply, pH, ionic composition, nutrient supply)
- quickly adapts to changes in conditions and metabolic demands
T or F: right & left heart arranged “in series”
True
T or F: Systemic circulation is primarily arranged “in parallel.”
True, oxygenated blood visits only one organ system before returning to pulmonary circulation (Exception: hepatic circulation)
T or F: Changes in metabolic demand or blood flow in one organ significantly affect other organs
False, due to the “parallel” arrangement of systemic circulation, other organs are not significantly affected.
List the 3 major layers of the heart
- epicardium (outer membrane = connective tissue & fat)
- myocardium (thick muscle layer)
- endocardium(inner membrane= endothelial cells, as in vessels).
What is the function of the pericardium?
Stiff & non-compliant, resists sudden distension of chambers. fluid-filled membranous sac, not connected to walls of heart
What are the 4 chambers of the heart?
- 2 atria (supply ventricles with blood)
- 2 ventricles (Left is bigger, supplies higher pressure to systemic circulation)
What are the 4 vessels of the heart?
- Vena cavae (superior & inferior): inlet vessel(s) into right atrium
- Pulmonary Artery – outlet vessel from right ventricle
- Pulmonary Vein – inlet vessel into left atrium
- Aorta – outlet from left ventricle
What are the 4 valves of the heart?
- Tricuspid valve – between right atrium & right ventricle
- Pulmonic valve – between right ventricle & pulmonary artery
- Mitral valve – between left atrium & left ventricle
- Aortic valve – between left ventricle & aorta
What are the atrioventricular valves?
Tricuspid & mitral valves, between atria & ventricles
What are the semilunar valves?
Pulmonic & aortic valves, between ventricles and great arteries
What are chordae tendonae?
tendon-like attachments that prevent valves from prolapsing into atria during ventricular
contraction.
Which valve only has 2 cusps?
Mitral has two cusps (bicuspid), others have three
What 2 structures initiate the heart beat and coordinate contraction?
- Sinoatrial Node (SA)
- Atrioventricular Node (AV)
Where is the SA node located?
R. Atrium (highly regulated by autonomic nervous system and many humoral factors)
What is the function of the AV node?
between atria and ventricles, slows conduction to allow atrial contraction to precede ventricular contraction
What is the His-Purkinje system?
specialized cells that rapidly conduct depolarization to trigger coordinated ventricular contraction.
T or F: The cardiac cells have more time for perfusion at high HR
False, less time for perfusion at higher heart rates since most coronary blood flow occur during diastole
Coronary veins drain into what structure?
Coronary sinus
This structure bifurcates to left anterior descending (LAD) artery and circumflex artery
left main coronary artery, primary blood supply to left atrium and left ventricle
This structure is the primary blood supply to right atrium and right ventricle, as well as posterior
part of left ventricle
right coronary artery
Describe blood flow through the heart starting with deoxygenated blood as it enters the heart.
superior & inferior venae cavae -> right atrium -> Right atrium contracts, increased pressure pushes open tricuspid valve ->blood enters right ventricle, Right ventricle contracts ->pushes open pulmonic valve -> blood enters pulmonary circulation via pulmonary arteries ->Oyxgenated blood returning from lungs in pulmonary veins enters ->left atrium, Left atrium contracts ->pushes open mitral valve -> blood enters left ventricle, Left ventricle contracts -> pushes open aortic valve ->blood enters systemic circulation via aorta.
Diameter of Aorta
25 mm
Characteristics of Arteries
- thick walled, resist expansion
- diameter ~ 0.2-6.0 mm,
- distribute blood to different organs
Characteristics of Arterioles
- relatively thicker walls (more vascular smooth muscle)
- diameter ~ 10-70 um
- highly innervated by autonomic nerves, circulating hormones, and local metabolites
- primary site of regulation of vascular resistance, via changes in diameter
Characteristics of capillaries
- smallest vessels (walls just single layer of epithelial cells, no smooth muscle)
- diameter <10 um; huge total surface area
- primary site of gas & nutrient exchange with interstitial fluid
Characteristics of Venules/veins
- thin walls relative to diameter compared to equivalent-sized arteries (but still some
smooth muscle), not much elasticity - diameter ~ 20 um – 0.5 cm
- Primary capacitance vessels of the body (most of blood volume)
- one-way valves compensate for lower pressure in venous system to ensure blood flows only in the correct direction
Diameter of Vena cavae
25-30 mm
List the 3 layers of arterial walls
- Tunica adventitia (outer layer, mostly connective tissue)
- Tunica media (middle, mostly innervated vasculars mooth muscle)
- Tunica intima (inner layer of vessel lined with vascular endothelium)
T or F: Tunica media is present in capillaries
False
Where is the site of atherosclerotic plaque formation?
Tunica intima
describe the histology of blood vessels
Just kidding hehe
Define microcirculation
vasculature from the first-order arterioles to the venules
What is the function of capillaries
siteofgas,nutrient,andwasteexchange.
What governs movement of substances between capillaries and tissue?
concentration and pressure gradients (highly
regulated via constriction/dilation of arterioles & precapillary sphincters)
What are precapillary sphincters?
smooth muscle bands at junction of arteriole and
capillaries
