LECTURE 5 cardiovascular system Flashcards
functions of cardiovascular system
bulk flow of blood, exchange with tissue
components of cardiovascular system
blood, heart, blood vessels
location of the heart
thoracic cavity, in middle mediastinum, surrounded by pericardium
orientation of the heart
oblique position within mediastinum, midline is angled, apex of heart projects to left of midline and anterior to the rest of the heart
superior right of heart
3rd costal cartilage, 1” right midsternum
superior left of heart
2nd costal cartilage, 1” left midsternum
inferior right of heart
6th costal cartilage, 1” right midsternum
inferior left of heart
5th intercostal space at midclavicular line
pericardium
partly covers great vessels, modified serous membrane
layers of pericardium
fibrous pericardium, parietal serosa, visceral serosa (epicardium)
pericardial cavity
between layers of serous pericardium, contains serous fluid, lubricates the heart while it beats
external features of the heart
interventricular sulcus (midline), coronary sulcus, coronary vessels (run along sulci), auricles of atria, apex, base
great vessels and major branches of heart
aorta, pulmonary trunk, inferior and superior vena cava
aorta branches
ascending aorta, aortic arch, descending aorta
ascending aorta branches
2 coronary arteries
aortic arch branches
brachiocephalic trunk, left common carotid artery, left subclavian artery
brachiocephalic trunk branches
right common carotid artery, right subclavian artery
descending aorta branches
many small branches to organs
pulmonary trunk branches
2 pulmonary arteries into lungs
layers of heart wall
epicardium (superficial): visceral serosa; myocardium (middle layer): cardiac muscle, contracts; endocardium (deepest/lining): simple squamous endothelium on CT, lines the heart, creates the valves
structure of fibrous skeleton of heart
made of dense CT, 4 rings and 2 trigone
functions of fibrous skeleton of heart
insertion for cardiac muscle, anchors valve cusps, prevents valves from opening too much, block electrical impulses from atria to venricles, contains arterioventricular node
heart chambers (4)
right atrium, right ventricle, left atrium, left ventricle
2 receiving chambers of heart
right atrium, left atrium
2 pumping chambers of heart
right ventricle, left ventricle
orientation of chambers of heart
atria superior to ventricles, arrangement is oblique (not linear), left atrium is posterior (base of heart)
pumps of heart (2)
right heart chambers = pulmonary pump, left heart chambers = systematic pump
right atrium receives
oxygen poor blood from body via superior and inferior vena cava and coronary sinus
features of right atrium
fossa ovalis: visible on interatrial septum (remnant of foramen ovale - prenatal), ventral wall contains pectinate muscles
right ventricle receives
oxygen poor blood from right atrium through tricuspid (right atrioventricular) valve
features of right ventricle
chordae tendinae: fibrous cords connecting valve cusps and papillary muscles, papillary muscles (3 groups): cone-shaped muscles with ventricles to which cordae tendinae are anchored, trabeculae carnae: muscle ridges along ventral surface, moderator band: muscular band connecting anterior papillary muscle to interventricular septum
right ventricle pumps
blood into pulmonary trunk via pulmonary semilunar valve
left atrium receives
oxygen rich blood from 4 pulmonary veins
features of left atrium
pectinate muscles: line only the auricle
left ventricle receives
blood from left atrium through bicuspid (left atrioventriuclar) valve
features of left ventricle
same structures as right ventricle, no moderator band, 2 groups of papillary muscles
left ventricle pumps
blood into aorta via aortic semilunar valve
heartbeat LUB
tricuspid valve and bicuspid valve close together
tricuspid valve
function to prevent backflow of blood into right atrium, 3 cusps made of endocardium and CT, flow of blood pushes cusps open, when ventricle is relaxed cusps hang in ventricle, ventricular contraction increases pressure and forces cusps closed
bicuspid valve
function to prevent backflow of blood into left atrium, 2 cusps made of endocardium and CT
heartbeat DUB
pulmonary semilunar valve and aortic semilunar valve close together
pulmonary semilunar valve
function to prevent backflow of blood from pulmonary trunk into right ventricle, made of 3 half moon cusps, when ventricle contracts, blood rushes past the cusps flattening them against artery wall and opening valve, after ventricular contraction blood refills the artery pulling cusps back into their cusp shaped position and closing valve
aortic semilunar valve
function to prevent backflow of blood from aorta into left ventricle, made of three half moon cusps, works same as pulmonary semilunar valve
flow of blood
oxygen poor blood enters RA from SVC, IVC and coronary sinus; travels through tricuspid valve into right ventricle; pumped out through pulmonary semilunar valve into pulmonary trunk and to lungs; after circulating through lungs oxygen rich blood returns to left atrium of heart through 4 pulmonary veins; oxygen rich blood travels through bicuspid valve into left ventricle; pumped out through aortic semilunar valve into aorta to be distributed to rest of body
external innervation of heart
cardiac plexus, changes rate of heart’s contractions, vagus nerve (parasympathetic innervation), sympathetic trunk (sympathetic innervation)
description of blood vessels
powered by the heart through ventricular contractions, carry blood to and from heart
types of blood vessels (3)
arteries (carry blood away from heart), capillaries (allow for gas exchange), veins (carry blood into the heart)
anatomy of arteries and veins
lumen, tunica intima (innermost layer), tunic media (middle layer), tunica externa (outermost layer)
tunica intima
thin innermost layer of blood vessels, endothelium, minimize friction
tunica media
middle layer of blood vessels, circular smooth muscle, collagen and elastic fibers
tunica externa
outermost layer of blood vessels, CT with elastic and collagen fibers, vaso vasorum, protects, strengthens, anchors
arteries in pulmonary circuit carry
oxygen poor blood away from heart
arteries in systematic circuit carry
oxygen rich blood away from heart
veins in pulmonary circuit carry
oxygen rich blood in to heart
veins in systematic circuit carry
oxygen poor blood in to heart
vessel walls in arteries vs. veins
thicker in arteries, arterial blood is under much higher pressure, tunica media is thicker in arteries, tunica externa is thicker in veins, veins have larger lumen, veins have valves and can use body movement to propel blood
description of capillaries
smallest blood vessel, don’t have all 3 layers (only one endothelial cell layer surrounded by basal lamina)
function of capillaries
exchange of oxygen, nutrients, hormones from blood to tissues, removes waste from tissues
capillary beds
network of capillaries with sphincters
portal system
special vascular circulation where blood goes through 2 capillary beds before returning to the heart to achieve 2nd function
vascular anastomoses
vessels that unite and connect, important if there were an obstruction
fetal circulation differences
fetus must supply blood to placenta, lungs do not need all of body’s blood sent to them because they do not function in gas exchange
umbilical vessels
2 umbilical arteries: carry blood away from fetus to placenta, 1 umbilical vein: carries blood in to fetus from placenta
foramen ovale
hole in the inter-arterial septum, allows blood to flow from RA to LA, bypasses RV because no gas exchange with lungs, becomes fossa ovalis postnatally
ductus arteriosus
carries blood from pulmonary trunk to aortic arch, allows heart and brain to receive the most highly oxygenated blood, bypasses lungs, becomes ligamentum arteriosum postnatally
cardiac conduction
intrinsic system initiating and coordinating contraction of heart muscles
sinoatrial node
“pacemaker”, initiates contraction of atria
atrioventricular node
impulse quickly pauses before spreading to atrioventricular bundle
atrioventricular bundle
splits into right and left bundles to conduct signals to apex of heart
purkinje fibers
subendocardial plexus, cause ventricular contraction cranially to push blood towards arteries
blood flow to supply the heart because
heart wall too thick for diffusion of nutrients
vessels for blood supply of heart
R & L coronary arteries, cardiac veins
