Circulatory system basics Flashcards
What are the 4 main functions of the circulatory system?
Distribution of gases and other molecules for nutrition, growth and repair; Chemical signalling; thermoregulation and mediation of inflammation and host defence response
What are the 2 systems that make up the circulatory system?
The cardiovascular system and the lymphatic system
What are the 3 main components of the cardiovascular system?
The arterial system, the heart and the venous system
What are the 4 chambers of the heart?
The left and right atrium
The left and right ventricle
What are the 2 phases of the double muscular pump?
Systole (atrial and ventricular) and diastole
What carries deoxygenated blood from the heart to the lungs?
The pulmonary trunk
What is the pulmonary trunk comprised of?
2 pulmonary arteries
What carries oxygenated blood from the lungs to the heart?
4 pulmonary veins
What carries deoxygenated blood from the body to the heart?
The inferior and superior vena cava
What carries oxygenated blood from the heart to the body?
The aorta
What are the 3 layers of the heart wall?
The epicardium, the myocardium and the endocardium
What is the epicardium an example of?
Visceral serous pericardium
What are the 2 atrioventricular valve?
The mitral valve and the tricuspid valve
On which side of the heart is the mitral found in?
The left
On which side of the heart is the tricuspid valve found?
The right
What are the 2 types of semilunar valve?
The aortic and the pulmonary
Where in the heart does the electrical impulse start?
The sinoatrial node
Describe the path that the electrical impulse travels down in the heart
The impulse starts at the sinoatrial node, before passing down to the atrioventricular node. It then passes down the right and left bundle of His in the inter ventricular septum, before spreading out to the myocardium via purkyne fibres.
What is the average pressure within an artery?
120/80 mmHg
What is the definition of bifurcate?
Splits into 2 branches
What is the definition of trifurcate?
Splits into 3 branches
What do the terms common and trunk indicate?
They indicate that the artery will definitely divide again
What occurs during vasodilation?
Smooth muscle in the tunica media relaxes, so the arterial lumen widens to increase blood flow to the organ or tissue
What occurs during vasoconstriction?
Smooth muscle in the tunica media contracts to reduce blood flow to the organ or tissue
What occurs when a vessel is in spasm?
The arteriolar smooth muscle contrast to help reduce blood loss following injury
What is anastomosis?
Arteries connect with each other without an intervening capillary network
What are the advantages of an anastomosis?
They provide alternative routes for blood to flow to supply the cells distal to an arterial occlusion
What is an occlusion?
A blockage
What is the Circle of Willis?
An arterial anastomosis of the brain
What are the advantages of the Circle of Willis in the brain?
May help to prevent a cerebrovascular accident (CVA/stroke)
What is collateral circulation?
A network of vessels that prevent damage from ischaemia
What is a disadvantage of an anastomosis?
They bleed from both sides of a cut so haemorrhage can be worse
What artery forms the scalp anastomosis?
The external carotid artery
What is an end artery?
An artery that provides the only arterial blood supply to a given area
What can an untreated occlusion of an end artery lead to?
Infarction of its territory
What is infarction?
Irreversible cell dead due to hypoxia
What is hypoxia?
Lack of oxygen
What is a myocardial infarction?
Occlusion of a coronary artery
What is a retinal infarction?
Occlusion of the central retinal artery
What is a fingertip infarction?
Occlusion of a digital artery branch
What does a myocardial infarction lead to?
A heart attack or death
What does a retinal infarction lead to?
Monocular blindness
What does a fingertip infraction lead to?
Amputation
What are the 4 parts of the aorta?
Ascending aorta, the arch of the aorta, the thoracic aorta and the abdominal aorta
What are the 2 branches of the ascending aorta?
Left and right coronary artery
How many branches of the arch of the aorta are there?
3
What are the components of the abdominal aorta?
3 unpaired midline branches and several paired, bilateral branches
What are the 3 branches of the arch of the aorta?
Brachiocephalic trunk, the left common carotid artery and the left subclavian artery
What are the 2 branches of the brachiocephalic trunk?
The right common carotid artery and the right subclavian artery
What does the subclavian artery become after it has reached the axilla?
The axillary artery
What does the axillary artery become when it reaches the arm?
The brachial artery
What are the 2 branches of the brachial artery?
The ulnar and radial artery
What are the 2 branches of the abdominal aorta?
The common iliac arteries
Where do the common iliac arteries supply blood to?
The pelvis, perineum and lower limbs
What are the 2 branches of the common iliac arteries?
The internal and external iliac arteries
What does the external iliac artery become when it reaches the hip?
The femoral artery
What does the femoral artery become when it reaches the knee joint?
The popliteal artery
What artery is found in the dorsal of the foot?
The dorsalis pedis artery
What is the area in which 2 veins merge known as?
A tributary
What 3 things assist the return of blood to the heart?
Venous valves to prevent back flow; skeletal muscle pump due to contraction of lower limb muscles and venue comitantes
What are vena comitans?
Small veins that run in pairs or more around an artery and use arterial pulsation to move blood back to the heart
What are the two general sets of veins?
Deep and superficial
What are the characteristics of a superficial vein?
Smaller and run into the superior fascia and then drain into deep veins
What are the characteristics of a deep vein?
Larger and run in deep fascia and in cavities
What are the 2 main venous systems?
Hepatic portal venous system and systemic venous system
What is the function of the hepatic portal venous system?
Drains venous blood from absorptive parts of the GI tract and associated organs to the liver for cleaning
What is the function of the systemic venous system?
Drains venous blood from all other organs and tissues into the superior and inferior vena cava
What do lymphatic capillaries collect?
Tissue fluid
What is the term given to the tissue fluid within the lymphatic capillaries?
Lymph
What is the function of the lymph nodes?
They contain white blood vessels to filter foreign particles and fight infection and cancer
Where is the lymph returned to?
The central veins in the root of the neck
Where does the right lymphatic duct drain into?
The right venous angle
What are the 2 lymphatic ducts?
The thoracic duct and the right lymphatic duct
Where does the thoracic duct drain lymph into?
The left venous angle
When can lymph nodes be palpated?
When they are fighting infection or taken over by a spreading cancer
What is the function of the papillary muscles?
They are attached to atrioventricular valves by chordae tendineae and prevent the opening of valves in the wrong direction
What is the structure and function of the trabecular carneae?
They are muscular columns that project in the ventricles of the heart to prevent suction that would occur between the flat surfaces
