Cardiovascular System Flashcards
Cardiovascular System
includes the heart (cardio) and (vascular) arterial (supply) and venous (drainage) systems. The capillary bed connects this continuous tubular pathway.
Function: transportation of water, Oxygen, CO2, nutrients, waste products and hormones
3 important capillary beds
- body (systemic circulation)
- heart (coronary/cardiac circulation)
- lungs (pulmonary circulation)
Heart
positioned left centered to sternum in the thorax (thoracic cavity); cardio
-pericardium
4 chambers (2 atria-receive; 2 ventricles- discharge)
upper limit: near the sternal angle (anteriorly) right border (from the R 3rd costal cartilage to the R 6th costal cartilage)
intervertebral disc between T4/T5 vertebrae (posteriorly)
inferior extent: diaphragm (heart NOT stationary, during respiration organs in thoracic cavity move)
Space between posterior heart and vertebral bodies (blood vessels: thoracic aorta, also esophagus)
Blood vessels
= vasculature
- arteries (supply)
- veins (drainage)
MORE venous plexes than arterial
Blood
RBCs
WBCs
platelets
plasma
ausculatation
(listening for heart sounds)
important to define cardiac borders
Standard PA view: right cardiac border
(from the R 3rd costal cartilage to the R 6th costal cartilage)
the superior vena cava, right atrium and inferior vena cava
Standard PA view: left cardiac border
(2nd intercostal space to the apex of the heart at the 5th intercostal space – midclavicular line)
Aortic arch, pulmonary trunk and left ventricle
Standard PA view: the inferior border
(on the superior surface of the diaphragm) (from the sternal end of the R 6th costal cartilage to the 5th intercostal space at/near the midclavicular line.)
the right ventricle and the left ventricle (apex) together
The superior border of the heart is at the __ costal cartilage on the R of the sternum and the ___ intercostal space on the L of the sternum.
3rd costal cartilage on R sternum
2nd intercostal space on L sternum
inferior border
lies on the diaphragm.
*Remember that the diaphragm is moving as we breathe so there is a little change in this position.
Systole
contraction of the heart
Diastole
dilation or filling of heart
ventricular diastole
filling of ventricles
atrial diastole
filling of atria
Atria
2 chambers of heart that receive deoxygenated blood (regardless of where its coming from/which circuit its associated with)
Ventricles
2 chambers of heart that discharge or pump oxygenated blood out to all circuits
atrioventricular valves
2
-outflow of atria/inflow of ventricles (R = tricuspid & L = Mitral)
tricuspid valve
right atrioventricular valve
-outflow of atria/inflow of ventricles
heard just to the left of the lower part of the sternum near the 5th intercostal space
mitral valve
left atrioventricular valve
-outflow of atria/inflow of ventricles
heard over the apex of the heart in the L 5th intercostal space at the midclavicular line
Pulmonary valve
RV outflow
heard over the medial end of the L 2nd intercostal space.
Aortic valve
LV outflow
heard over the medial end of the R 2nd intercostal space.
R side of heart
Pump for Pulmonary Circuit (heart to lungs to heart)
Deoxygenated blood received
The RA (right side of sternum) receives deoxygenated blood and sends it to the lungs to be oxygenated – returning blood goes to the LA. RA – RV – lungs LA
L side of heart
Pump for Systemic Circuit (coronary and whole body)
Oxygenated
The LA receives oxygenated blood and sends it to the heart and body to be used – returning to the RA
LA – LV – body/heart – RA
arteries
carry blood away (artery > away) from heart
- systemic circulation: carries oxygenated blood away from heart
- pulmonary circulation: carries deoxygenated (oxygen poor) blood (not always oxygenated because its in an artery)
smallest artery is a arteriole.
capillaries
smallest of blood vessels; very thin wall
main role: allow exchange of materials between blood and body tissues.
veins
carry blood towards heart (VEINOUS RETURN: TO)
- systemic circulation: carries oxygen-poor blood
- pulmonary circulation: carries oxygenated blood
smallest vein is a venule.
Describe the flow of blood from the heart through blood vessels and back to the heart
♥ -> Arteries -> Arterioles -> Capillaries -> Venules -> Veins -> ♥
3 layers or tunics of walls of blood vessels
*smallest blood vessels do NOT have 3 tunics or layers in walls
1) Tunica interna or Tunica intima (in contact with blood: endothelium, basal lamina, subendothelial)
2) Tunica Media
3) Tunica Externa or Tunica Adventitia
Tunica interna (intima)
In contact with actual blood
Three Parts: a. endothelium (simple squamous) b. basal lamina c. subendothelial layer (internal elastic membrane/lamina – arteries and some arterioles)
Tunica Media
contains rings of smooth muscles cells responsible for vasoconstriction and vasodilation; can also contain sheets or lamellae or laminae of elastin
(external elastic membrane/lamina – arteries)
functional: constrict/dilate
MEDIA = MUSCLE
Tunica Externa (Adventitia)
outermost layer, will merge with outer connective tissue (continuous with next structure)
in larger vessels this tunic contains a vasa vasorum and a nervi vascularis (own blood supply and innervation)
What is the thickest layer of the vessel wall in arteries?
tunica media (muscle cells, pumping, force)
What is the thickest layer of the vessel wall in veins?
tunica externa
4 types of arteries
1) Elastic or Conducting arteries (Large arteries)
2) Muscular or Distributing arteries (Medium arteries)
3) Small arteries
4) Arterioles
Elastic or Conducting Arteries
(Large Arteries)
largest diameter arteries (diameter greater than 10mm)
Walls contain large amounts of elastic fibers (pressure reserve)
- allows arteries to expand/ recoil
- important vessels in helping propel blood onward while ventricles are relaxing
- act as pressure reserve
Muscular or Distributing Arteries
(Medium Arteries) MEDIUM: MUSCULAR
medium-sized arteries (2mm to 10mm diameter)
Walls contain large amounts of smooth muscle
- important in regulating the blood flow to specific body regions
- smooth muscle cells in circular orientation, responsible for vasoconstriction (i.e. reduction in lumen diameter) and vasodilation (i.e. increase in lumen diameter).
Small Arteries
0.1mm to 2mm in diameter
As many as eight layers of smooth muscle in their tunica media
Arterioles
smallest diameter artery; 10μm to 100μm diameter
Only one or two layers of smooth muscle in the tunica media
Capillaries
Smallest diameter of blood vessels: 4μm-10μm
Thin wall – endothelial cell and its basal lamina
Main role: allow the exchange of materials between blood and body tissues
4 types of veins
1) Venule
2) Small Veins
3) Medium Veins
4) Large Veins
Venule
smallest diameter veins (diameter of 10μm to 100 μm); receive blood from capillaries
Two types:
-Postcapillary Venule – endothelial cell with basal lamina and pericytes; no tunica media and no adventitia.
-Muscular Venule – possess a tunica media with one or two layers of smooth muscle and a thin tunica adventitia; typically no pericytes here.
Small veins
0.1mm to 1mm in diameter
Receive blood from muscular venule.
Medium veins
1mm to 10mm in diameter
All three layers present.
Large veins
larger than 10mm in diameter
All three layers present.
Most veins in limbs have valves which do what?
prevent backflow
thin folds of tunica intima – endothelial cells over a thin layer of connective tissue
the heart is located in which body cavity?
thoracic
True or false, there are more venous return pathways than arterial supply pathways?
TRUE, more venous plexuses (a lot, important for drainage) than arterial plexuses (a few)
Why is it important to know where the heart is located clinically?
AUSCULTATION
True or false, the heart is stationary, but during respiration organs in thoracic cavity move
FALSE heart and majority organs in thoracic cavity moving because of breathing
the systemic (body) circuit begins at the _____ and ends at _____
left side of heart (also coronary circuit)
left ventricle -> right atrium
oxygenated
beginning of pulmonary circuit is _____, which goes to the lungs, and returns to the ______
right side of heart
right ventricle -> left atrium
deoxygenated
pathway of blood through the heart
RA > right AV valve (tricuspid) > right ventricle > (TO LUNGS) pulmonary semilunar valve > pulmonary trunk > pulmonary arteries > pulmonary arterioles (TO HEART) > left atrium > bicuspid or mitral valve > left ventricle > aortic semilunar valve >
(TO BODY) ASCENDING aorta > arch > descending aorta (thoracic and abdominal aorta)
pathway of blood through the body
Left atrium > artery > arterioles > capillaries > venules > veins > Right atrium
2nd intercostal space has ____ auscultation points, corresponding to ____ valve(s)
2
AP: aortic and pulmonary
5th intercostal space contains the _____ auscultation point
tricuspid valve (just left of sternum)
apex of heart is in the ___intercostal space, near the _____ line, and is the point for auscultation of the ____ valve
5th, midclavicular, mitral valve
the smallest of blood vessels are
capillaries
THIN: EXCHANGE
describe the general schematic of blood vessels leaving the heart to the body and returning back to the heart
heart > ELASTIC (conducting, large) arteries (lots of pressure) > Muscular (distributing arteries, decreased pressure) > Arterioles (resistance vessels) > capillaries (exchange vessels) > venule > small veins > medium veins> large veins (diameter larger again, but pressure still low) > heart
internal elastic membrane
between the tunica intima and tunica media
fenestrated: allow passage of materials
arteries and some arterioles
vasa vasorum and a nervi vasculari
in tunica externa/adventitia
thickest layer in arteries
tunica MEDIA (think functional, pushing blood out, lots muscle, keep it open)
thickest layer in veins
tunica externa (outer layer: bind/support, returning blood is main job, just need to contain it)
capillaries contain a tunica media and tunica externa, true or false?
FALSE- gotten rid of these (remember, they are SMALL, and don’t have typical 3 layer structure)
-made of endothelial cell and basal lamina (INTIMA/INTERNA layer portions)
50,000/60,000 vessels
-Postcapillary Venule
endothelial cell with basal lamina and pericytes; no tunica media and no adventitia.
Muscular Venule
possess a tunica media with one or two layers of smooth muscle and a thin tunica adventitia; typically no pericytes here.
ALL 3 layers back
valves in limbs are made of
thin folds of tunica intima – endothelial cells over a thin layer of connective tissue
