introduction to the circulatory system Flashcards
what is the circulatory system made up of
the cardiovascular system and the lymphatic system
what is the cardio vascular system made up of
the arterial system, the heart, and the venous system
describe pulmonary circulation
right side of heart → lungs → left side of heart
describe systemic circulation
left side of heart → capillary beds of organs and tissues → right side of heart
name and describe the 3 layers of the heart
- epicardium is the outer layer of the heart, it is a visceral serous pericardium (a fibrous sac that encloses the heart and great vessels)
- myocardium is the middle cardiac muscle layer (does the pumping)
- endocardium is the internal layer of the heart which is continuous with the epithelium of blood vessels connecting with the heart
describe the four step conduct system of the heart
- electrical impulse starts at sinoatrial node (atrium contract)
- impulse travels to atrioventricular node at atrioventricular septum
- impulse travels doen left and right bundles to the bundle of His in the inter ventricular septum
- impulse spreads out to myocardium through conductive fibres (ventricles contract)
use pics in notes
what to arteries do
each artery (and its branches) carry blood to a territory
describe the three layered structure of a blood vessel
- tunica intima is the internal layer made up of a single layer of squamous endothelial cells supported by a basal membrane a thin layer of connective tissue
- tunics media is the middle layer made up of smooth muscle and elastic fibre, its thickness varies tremendously
- tunica adventitia is the external layer made up of connective tissue
what is sympathetic tone and where and why is it used
- background low level contraction of smooth muscle
- found in arterioles or some arteries called muscular arteries
- smooth muscle in the walls of arterioles can contract to narrow the vessels lumen (inner space)
how does sympathetic tone work
due to tonic (continuous) production of action potentials to arterioles by sympathetic nerves
what is an anastomoses
where arteries connect to eachother without an intervening capillary network
what does an anastomoses provide (2)
- provides alternative routes for blood flow to supply cells distal to an arterial occlusion (blockage?)
- each alternative route given by an anastomosis is called a collateral
what is an end artery
the only arterial supply to given area of the body
what is infarction
irreversible cell death due to hypoxia (when there is not sufficient oxygen available on a tissue level to maintain homeostasis) caused by loss of arterial blood supply
- this is the result of an untreated occlusion of an end artery
draw and name the four heart valves
- tricuspid valve is between right atrium and ventricle
- pulmonary valve is between right ventricle and pulmonary vein?
- mitral (bicuspid valve) is between the left atrium and ventricle
- the aortic valve is between the left ventricle and the aorta
draw all different areas and branches of the aorta
compare with ppt or notes
where do the left and right coronary arteries supply blood to
heart muscle
where do branches of the arch of the aorta supply blood to
upper limbs and head
where does the descending aorta supply blood to
the thorax and abdomen
within the abdomen, what does the abdominal aorta branch in to and what does this supply
in to the two common iliac arteries that provide blood to the pelvis and lower limbs
what does the venous system do
veins drain deoxygenated blood from a territory
how is venous blood pumped back towards the heart and what is this called
called venous return
- venous valves
- skeletal muscle pump
- accompanying veins
descried are superficial veins
smaller, run within superficial fascia and drain in to deep veins
describe deep veins
larger, run deep to the deep fascia in cavities, often in neuromuscular bundles
describe the hepatic portal venous system
drains venous blood from absorptive parts of the GI tract and associated organs for cleaning
describe the systemic venous system
drains venous blood from all of the organs and tissues in to the superior or inferior vena cava
what does the lymphatic system do
lymphatic capillaries collect tissue fluid (lymph)
describe lymphatic circulation
- lymphatics carry lymph through lymph nodes
- eventually lymph is returned in to the central veins in the root of the neck
a. lymph from superficial lymphatics -> deep lymphatics
b. lymph from right lymphatic duct -> right venous angle
c. lymph from thoracic duct (which is on the left and the only one large enough to be found in dissection) -> left venous angle
can lymph nodes usually be palpated
no as they are to small, however, lymph nodes fitting infection or being taken over by a spreading cancer usually enlarge and can be palpated or seen on a ct
describe the layers in-between each layer of the blood vessels
- the tunica intimate is separated by the tunica media by a layer of elastic tissue by called the internal elastic membrane
- the tunica media is separated from the tunica adventitia by a layer of elastic tissue called the external elastic membrane
