Gross anatomy of CVS Flashcards
What is the basic pathway of blood?
Blood enters the right atrium from the superior and inferior vena cava.
Blood enters into the right ventricle, then into the lungs by the pulmonary arteries for oxygenation.
Blood then enters the left atrium via pulmonary veins, and passes into the left ventricle.
Blood is then supplied to the rest of the body by the aorta.
Where is the heart?
In the thoracic cavity, protected by the ribcage, with the sternum in the centre.
More of the heart is found left of the sternum.
The apex of the heart (bottom) is located in the 5th intercostal space.
What is the mediastinum?
An area in the centre of the thorax that contains the heart and other structures.
What are the boundaries of the mediastinum?
Sagittal plane:
The sternum is the anterior boundary.
The vertebrae is the posterior boundary.
The superior boundary is the superior thoracic aperture.
The inferior boundary is the diaphragm.
What are the mediastinum subdivisions?
At the T4/5 vertebral layer the mediastinum divides into the superior and inferior mediastinum.
The inferior is subdivided into anterior, middle and posterior.
The middle is where the heart is.
The aorta passes into the superior mediastinum, then the posterior mediastinum.
What is lateral of the mediastinum?
Laterally are the right and left lungs.
The lungs have tissue called pleura.
What is the pericardium?
A sac structure that surrounds the heart.
Comprised of thin 2 layers that secretes fluid and fills the sac.
Peri - around
What are the functions of the pericardium?
Protects the heart
Holds the heart in place above the diaphragm
Provides lubrication by the fluid it secretes
What are the layers of the pericardium?
Inner layer is the visceral layer
The outer layer is the parietal layer
Visceral layer is separated from the parietal layer by the pericardial cavity
Cells in the layers secrete fluid into the cavity, lubricates the walls of the heart to prevent friction.
What is the orientation of the heart?
Posterior (back) of heart is laid down on the diaphragm.
Apex (tip) of heart points anteriorly - towards ribcage.
Base of heart projects towards the vertebrae posteriorly.
What are the divisions of the heart?
Interventricular septum divides the left and right ventricles
Interatrial septum divides the left and right atria
Coronary sulcus separates the atria from the ventricles.
Divisions are visible on the heart surface as grooves - interventricular sulcus
What is the right atrium?
Superior vena cava supplies deoxygenated blood from above.
Inferior vena cava supplies blood from below.
The pectinate muscle in the wall contracts and allows the heart to pump blood.
The tricuspid valve prevents backflow from the ventricle into the atria.
What is the sinoatrial node?
An electrical conductor.
Nervous tissue found in the wall of the right atrium that determines heart rate.
It is influenced by other nerves.
What is the coronary sinus?
Coronary arteries supply blood to the walls of the heart.
The coronary sinus is an opening where the blood from the coronary vessels can enter into the right atrium to go to the lungs.
What is the fossa ovalis?
A depression in the interatrial septum.
Remnant from the womb where oxygenated blood was supplied from the mother.
Used to bypass the lungs and go straight into left atria.
Closed upon birth.
What is the right ventricle?
The tricuspid valve prevents backflow into the atrium.
The chordae tendineae prevents the vale swinging backwards.
The trabeculae Carneae muscle in the wall pumps blood in the right ventricle.
Blood is then pumped into the pulmonary trunk, and the pulmonary valve prevents backflow into the ventricle.
What is the left atrium?
Blood enters left atrium from pulmonary veins, then goes to left ventricle.
Mitral valve prevents backflow from ventricle to atria.
Wall of left atrium is smoother than right atrium, there is less pectinate muscle.
What is the left ventricle?
Very thick wall, enough to generate force to pump blood around the whole body from aorta.
Mitral valve prevents backflow into atria.
Chordae tendineae, attaches to valves to prevent swinging by the flow of blood.
Papillary muscle is thick and attaches to tendineae.
What are the heart valves?
Tricuspid valve, between right atrium and right ventricle.
Pulmonary valve, between right ventricle and pulmonary trunk.
Mitral valve, between left atrium and left ventricle.
Aortic valve, between left ventricle and aorta.
What are the papillary muscles and chordae tendineae?
Tricuspid and mitral valve contain these.
When the left ventricle contracts, papillary muscle contract and pull on tendineae, creates tension, prevents valve cusps from opening backwards, so blood does not flow into atria, rather goes into aorta.
What are the coronary arteries?
Supply the walls of the heart.
Left and right arteries branch to supply the different chambers of the heart.
If blocked, heart is not oxygenated enough - myocardial infarction
Coronary bypass can prevent this.
What is the aortic valve?
Three cusps, no papillary muscles or chordae tendineae.
Cusps collect the blood that flows back, causes widening and the cusps come into contact to close the gap, stops backflow of blood into ventricle from the aorta
Two little openings for coronary arteries so that blood that flows back on next contraction is pumped into coronary arteries.
What are the cardiac veins?
Cardiac veins bring deoxygenated blood from the wall of the heart into right atrium.
Blood from veins drains into coronary sinus, which opens into right atrium, to go and become oxygenated in the lungs
What is the nervous innervation of the heart?
Heart is under influence from autonomic nervous system - no conscious control, has sympathetic and parasympathetic branches.
Sympathetic branch increase heart rate and force of contraction via the sinoatrial node.
What are the great vessels of the heart?
Superior and inferior vena cava bring blood to right atrium.
Pulmonary artery brings blood from right ventricle to lung.
Pulmonary vein brings blood from the lung into the left atrium - 4 pulmonary veins, 2 for each lung.
Aorta takes blood from left atrium to rest of body.
What are arteries?
Arteries supply oxygenated blood to tissues and organs.
Except for the pulmonary artery.
Arteries have branches, that subdivide into further branches.
What are veins?
Veins drain deoxygenated blood from tissues and organs.
Except for the pulmonary vein.
Veins have tributaries - different veins come together to form larger veins.
What is the aorta?
Aorta goes from left ventricle to the body.
Forms the arch aorta
Before the arch is ascending aorta.
After the arch is descending aorta, descends through thoracic cavity then into the abdominal cavity - thoracic aorta.
What are the branches off the aorta?
Brachiocephalic artery subdivides into right subclavian artery right common carotid artery.
Right subclavian artery supplies the upper limbs.
Carotid artery supplies the head and neck.
Left common carotid and left subclavian come directly off the aorta.
What is the abdominal aorta?
Abdominal aorta supplies the abdominal organs and pelvis.
It splits into two to form the two vessels which supply the lower limbs - the common iliac arteries.
What arteries branch from the abdominal aorta?
The renal arteries supply the kidneys, which filter blood and produce urine.
Gonadal arteries supply the testes and ovaries, and are very long.
What is the gastrointestinal tract blood supply?
Coeliac trunk supplies upper GIT - stomach and some of small intestine.
Superior mesenteric supplies rest of small intestine and some large intestine.
Inferior mesenteric artery supplies rest of large intestine and the rectum.
What else does the coeliac trunk supply?
Spleen and liver supplied from the coeliac trunk.
Spleen and liver filter dead RBCs.
What is the upper limb blood supply?
Subclavian artery majorly supplies the upper limb.
It passes into the armpit and forms auxiliary artery, then passes to brachial artery.
What is the blood supply of the lower arm?
Ulnar artery and radial arteries supply the forearm and hand.
Form palmar arch - collateral circulation - tissue is supplied by more than 1 blood vessel.
If one branch is blocked, can still have blood supply to the palmar arch.
What is the upper limb blood drainage?
Median cubital vein is superficial - for giving injections or taking blood samples as close to the skin.
Subclavian vein is pathway from the upper limb.
What is the lower limb blood supply?
Aorta bifurcates into two common iliac arteries.
Divides into external iliac artery and internal iliac artery.
External iliac passes out of pelvis, passes under ligament and becomes femoral artery - major blood supply to lower limb.
What is the lower limb drainage?
Deep veins - can’t see them at skin level, drain to femoral vein.
Superficial veins are the great saphenous and small saphenous vein, also drain to femoral vein.
These have valves to prevent backflow of blood, because it is at a lower pressure and against gravity.
What happens when valves in the legs stop working?
Valves can stop working properly, cause varicose veins, causes blood pooling in veins.
Caused by age or disease.
What are the pulse points?
Arteries of lower limb can be used for pulse.
Brachial artery often used to measure blood pressure.
Carotid pulse can be felt in the neck.
What is the head and neck blood supply?
Common carotid artery brings blood to head and neck, it divides into external and internal common carotid artery.
External carotid stays superficial - supplies face muscles and skin.
What is the internal carotid artery?
Brain is supplied by internal carotid artery and vertebral arteries, which branches from subclavian arteries, they go into the skull and supply the brain.
When arteries are cut off can cause stroke.
What is the vein drainage of the head and neck?
Internal jugular vein drains from brain to heart.
External jugular vein drains from superficial structures.
They go to superior vena cava and back to the heart.
