Cardiovascular system anatomy Flashcards
Name the 3 circulations in the cardiovascular system
Systemic, pulmonary & coronary
Describe the function of the systemic circulation
Systemic circulation refers to blood being delivered to the whole body. It is a longer pathway with five times more friction than the pulmonary pathway.
LV wall contains more myocardium to generate enough pressure to push blood all around the body, this circulation receives blood from the lungs via the pulmonary vein and is pumped out via aortic trunk
Describe the function of the pulmonary circulation
Pulmonary circulation refers to blood being pumped to the lungs and then back to the heart, a much shorter circuit which occurs under lower pressure
Oxygen poor blood returns to RA from the body, carried in 2 pulmonary arteries to the lungs
Describe the function of the coronary circulation
Coronary circulation supplies the heart with oxygenated blood itself when the heart is relaxed, delivering O2, F.A’s and glucose etc, this is the shortest form of circulation. It consists of 2 left and right arteries.
Order and explain the layers of heart tissue
The heart is surrounded by pericardium
1. Fibrous pericardium a tough and dense layer, involved in the protection of the heart, anchors the heart in place and to surrounding BV’s, prevents heart from overfilling with blood
2. serous pericardium (visceral & parietal) The serous parietal pericardium & visceral produces pericardial fluid to lubricate the heart, into the pericardial cavity, found between the parietal & visceral layer, parietal also covers the roots of large BV’s & allows large arteries to exit. The visceral layer
3. pericardial cavity, a fluid-filled space between parietal and visceral, fluid reduces surface tension/ friction, providing lubrication
4. epicardium, outer most layer of the heart, acts as protection & involved in signaling, made of connective tissue, part of the pericardium (visceral layer), made of a single layer of cells
5. Myocardium, a thick & muscular layer, made of cardiac muscle fibres that contract together, so the heart contracts as a unit due to the bundle arrangement of fibres. Allows force to be generated and maintains high BP
6. endocardium, inner most layer of the heart, made of a thin layer of
squamous endothelium, lines 4 chambers, provides a physical barrier, protective, covers fibrous skeleton of valves, involved in signaling
7. the cardiac skeleton is a dense network of connective tissue that reinforces myocardium & anchors cardiac fibres, allows APS to spread along specific pathways
Describe the positioning of the heart
The heart lies to the left, lies in the mediastinum, the apex of the heart points to the left hip. found between the lungs, 2/3 to the midline
Define the fossal ovalis
a shallow depression in the interatrial septum signifies spot where the foramen ovale once was, closed during the baby’s first breath
What is the function of blood vessels
To transport nutrients to respiring tissues e.g., glucose, oxygen etc
To transport heat in the blood to maintain body temperature for efficient enzyme activity
To remove waste products from tissues and deliver to excretory organs e.g., CO2 to lungs
Name the differences between the right and left chambers of the heart
Left chamber is thicker than right chambers. In LV there is more myocardium to generate a greater force to push blood around the body, not needed in RV as a shorter circuit. the valve between the right chambers is known as the tricuspid valve, whereas the left chambers the valve is the mitral valve
What are the 4 valves and their positioning in the heart
Tricuspid RA-RV
Mitral LA-LV
Pulmonary valve RV-Pul vein
Aortic Valve-LV to aortic trunk
describe the structure and function of arteries
consists of 3 layers: tunica externa, tunica media & tunica intima
Tunica intima contains thin flat layer of endothelium which are smooth to reduce friction as blood flows
Tunica media consists of elastic fibres and smooth muscle, enabling stretch and recoil of arteries as well as vasoconstriction and vasodilation, regulates blood flow, elastic fibres prevent arteries from bursting under high BP, creates extra surges in pressure
Tunica externa: provides strucutural support and mechanical strength to BV, made of collagen fibres, prevents bursting under high BP & maintains shape
small lumen, impermable, rapid flow, high BP, can constrict
describe the structure and function of veins
Veins have much thinner walls, blood flows slower & at lower pressure, less elastic fibres, and smooth muscle, and no need for contraction. They have a wider lumen than arteries
tough outer layer of collagen fibres to provide strength, and prevent bursting from external pressures.
Contains veins to prevent the backflow of blood, which flows down the pressure gradient
Impermeable, cannot constrict, transports blood at low BP, wide lumen larger volume of blood carried
describe the structure and function of capillaries
Capillaries are involved of exchanging of substances between blood & cells, they link arteries and veins together.
Single layer of endothelial cells providing a short diffusion distance. They are highly branched forming a complex network, contain capillary beds which provide a large SA for diffusion
Narrow diameter to ensure RBC are squeezed when passing, speeding up transfer of O2, Gaps between endothelium allow passage of substances into surrounding cells
describe the structure and function of the aorta
Aorta is dog-bone shaped to allows cusps to open due to pressure difference, allows cusps to never close,
The aorta is divided into four sections: ascending aorta, aortic arch, descending thoracic aorta, and abdominal aorta.
Transports oxygenated blood away from the heart and to the rest of the body
Name the 2 divisions of the left coronary artery
The left arteries: run down the L side of the heart & split into the anterior interventricular artery which follows the sulcus and supplies blood to LV wall & septum and the circumflex artery which supplies LA and Posterior walls of LV
Name the 2 divisions of the right coronary artery
Right arteries: run down the R side of the heart and bifurcate into marginal artery & post Intrv artery
Right marginal supplies myocardium & lateral side
Post intrv A: runs down to the apex and post ventricular walls, it merges with the anterior intrv artery. delivers to RA and most of RV
What is the total blood volume at rest and during exercise
Just below 6 litres
Closer to 17000-17500ml
Describe the structure and function of the coronary sinus
It collects the blood draining from the myocardium which is deoxygenated and drains it into the RA, largest vein in the heart
Name the 3 divisions of the cardiac sinus (coronary veins)
Composed of 3 veins
great cardiac vein: found in anterior intrv sulcus
middle cardaic vein: found in post intrv sulcus
small cardiac vein: empties into RA
Describe the adaptions of veins
Valves have valves to prevent the blood from flowing backwards, this allows blood to flow in one direction
Large veins found between muscles, this allows them to be squeezed during muscle contraction, this forces blood back towards the heart
Breathing squeezes veins, the chest acting as a pump, pushing the blood back to the heart
Describe the structure of the pulmonary valve
The pulmoary valve has 3 cusps, left, right & anterior
Describe the structure of the tricuspid valve
Tricuspide valves hs 3 leaflets, anterior, posterior and septal leaflet. Incomplete fibrous ring surrounding valve
Describe the structure of the mitral valve
Contains the biggest opening, contains an anterior and posterior leaflet, has a fibrous ring around the valve, ring is incomplete to accommodate movement
Describe the cause of a stitch
digestion cannot occur effectively once exercise occurs, eating too close to exercise causes a stitch, as blood flow is diverted to muscles rather than organs involved in digestion
Describe the function of chordae tendinae and papillary muscles
Chordae tendinae are the heartstrings which hold the valves in place, preventing inversion
Papillary muscles contract during systole to prevent prolapse or inversion of valves
connects to valves via chordae tendinae, prevent opening of valves during diastole
How is blood returned to the heart
Valves- preventing backflow of blood
pressure-veins flow back to the heart at low pressure, is slightly higher than pressure in right side of heart, flow down pressure gradient
skeletal pump-veins are housed between muscles, squeezes veins to generate pressure to push blood in veins back to the heart
respiratory pump- rising and falling of chest squeezes veins, to force blood in veins back to the heart
Explain the pulse
is the pressure felt in a artery that lies close to the body’s surface, it is a result of systolic pressure, can be counted from femoral artery, radial artery, brachial artery
Describe the structure and function of auricles
They are protruding appendages, The Right auricle increases arterial volume & capacity. Left auricle aids in pumping blood out of heart
How does the circulation in an infant differ from the circulation in an adult
Blood is oxygenated in the placenta and not the lungs, receives oxygen via mum. Infants have a foramen ovale, gap between chambers, allows blood to bypass the lungs
describe the structure and function of arterioles
They link arteries to capillaries, contain smooth muscle with less elastic fibres, capable of constriction.
During constriction, blood flow is prevented from entering the capillary bed.
During relaxation blood flows freely into capillary bed.
describe the structure and function of venules
Link capillaries to veins, they have very thin walls with little smooth muscle, venules merge to form a vein
Define the coronary sulcus
The hearts ‘grooves’ found on the surface of heart, shaped like a crown
Define pectinate muscles
This is a bundle of fibres that forms ridges on walls of RA, looks like needles, In LA pectinate muscle only found in auricle. They increase the contractile force of the heart without increasing mass of heart
Define the crista terminalis
A c-shaped ridge that divided the RA into anterior and posterior regions
Define trabeculae corneae
irregular ridges of muscles that mark the ventricular chambers
