Cardiovascular and Circulatory System Flashcards
Give the functions of the circulatory system
Distribution of gases and other molecules
Chemical signalling
Thermoregulation
Mediates inflammation and the immune response
Name and describe the basics of the 2 main circulations of the cardiovascular system
Pulmonary Circuit:
Right ventricle –> Lungs –> left atrium
Systemic Circulation:
Left ventricle –> capillary beds –> right atrium
Give the terms for the contraction and relaxation of the heart
Contraction - Systole
Relaxation - Diastole
Describe the timing relationship between the contraction of both atria, and of both ventricles.
Both atria contract at the same time
Both ventricles contract at the same time
Name and describe the layers of the heart
Epicardium (external) - visceral serous pericardium
Myocardium (middle) - Cardiac muscle layer. thickest layer
Endocardium (internal) - continuous with the endothelium of the blood vessels connecting with the heart
Name the chambers of the heart
Right atrium
Left atrium
Right ventricle
Left ventricle
Name the great vessels of the heart, and name the chamber they flow into or out of
Superior vena cava - into the right atrium
Inferior vena cava - into the right atrium
Pulmonary veins - into the left atrium
Pulmonary trunk - out of the right ventricle
Aorta - out of the left ventricle
Name and give the location of the cardiac valves
Tricuspid valve - from right atrium to right ventricle
Pulmonary valve - from the right ventricle to the pulmonary trunk
Mitral (bicuspid) valve - from left atrium to left ventricle
Aortic valve - from left ventricle to the aorta
remember the tricuspid is before the bicuspid, as you “try before you buy”
What is the purpose of the cardiac valves?
To ensure uni-directional blood flow through the heart
Give the locations of the SA node, and the AV node
SA node - the top right of the right atrium
AV node - at the bottom of the interatrial septum
Describe the basic process of conduction in the heart
1: The impulse starts at the sino-atrial node. Causing both atria to contract
2: The impulse travels to the atrio-ventricular (AV) node
3: Travels down the right and left bundles in the interventricular septum
4: Spreads out to myocardium through conducting fibres. Causing both ventricles to contract
Name and describe the 3 layers most blood vessels are comprised of
Tunica intima - the innermost layer. Endothelium
Tunica media - the middle layer. Smooth muscle and elastic fibres
Tunica adventitia - the outermost layer. Connective tissue
What is the name of the interior of a blood vessel?
The lumen
Nerves, arteries and veins often are found in a together, name this grouping?
A neurovascular bundle
Define the terms “Birfurcation” and “Trifurcation”
Birfurcation - division of a vessel or nerve into 2 branches
Trifurcation - division of a vessel or nerve into 3 branches
Define vasoconstriction and vasodilation
Vasoconstriction - contraction of the smooth muscle of the arterioles (Not Arteries) to reduce blood flow
Vasodilation - dilation of the smooth muscle of the arterioles (Not Arteries) to increase blood flow
Define sympathetic tone
The low level, background, contraction of arteriolar smooth muscle due to tonic (continuous) stimulation by sympathetic nerves.
It maintains the normal diameter of the arterioles
Define anastomoses and give its purpose
Anastomoses - where arteries connect directly (with not capillary bed)
Their purpose is to provide alternative routes (collaterals) for blood to flow past an arterial occlusion
Define the term infarction
Irreversible cell death due to hypoxia, caused by he loss of arterial blood supply
Define the term terminal (end) artery, and give the consequence of its occlusion
Terminal (end) arteries - an artery that provides the only arterial blood supple to the area of the body (e.g. there are no collaterals)
The occlusion of a terminal artery can result in infarction
How does the aorta help to maintain peripheral flow during diastole?
Elastic recoil. Its elastic walls, which have expanded during systole, recoil, reducing its internal volume thus increasing pressure
Name the 4 parts of the aorta, and give their locations
The ascending aorta - as it leaves the heart
Arch of the aorta - as it arches round
Thoracic aorta - as it descends behind the heart
Abdominal aorta - as it descends through the abdomen
Name the branches of the arch of the aorta
As blood flows:
1: Brachiocephalic trunk
2: Left common carotid artery
3: Right subclavian artery
Name the artery that supplies the upper limb
Axillary artery
Describe the arteries that bifurcate from the abdominal aorta to supply the lower limb
-Abdominal aorta into - Common iliac arteries (x2) into -internal iliac arteries (x2) and external iliac arteries (x2)
Compare the lumens of arteries and veins
Arteries lumens are maintained in a circular shape
Veins lumens are not maintained in a circular shape and are collapsed when empty
Where in the body can veins with valves be found
In the limbs
Name and describe the 3 elements that important in allowing venous return
Venous valves - ensure uni-directional flow against gravity in the limbs
Skeletal muscle pump - the contraction of skeletal muscles (mainly in the lower limb) force blood to move through the valves
Accompanying veins - small veins usually run alongside an artery in a sheath. The pulsation of the artery pushes the venous blood along
Name and describe the 2 types of vein
Superficial veins - Smaller and run withing the superficial fascia
Deep veins - Larger and run deep to the deep fascia & in cavities. Often in neurovascular bundles
*superficial veins drain into deep veins
Name and describe the 2 main venous systems
Hepatic portal venous system - Drains blood from the absorptive parts of the GI tract and associated organs to the liver for “cleaning”
Systemic venous system - drains blood from all other organs and tissues
Describe the wall of a capillary
Its walls are made up of a single layer of endothelial cells
Describe the transition to different vessel types as blood circulates through the body
Arteries to Arterioles to Capillaries to Venules to Veins
What is the function of lymphatic capillaries?
To collect tissue fluid (fluid that leaks out when blood flows through a capillary bed)
Describe the flow of lymph through the lymphatic system
The lymphatic capillaries form lymphatic vessels
These superficial vessels drain into deep lymphatic vessels
These flow through lymph nodes
The lymph is returned into venous circulation at the venous angles in the root of the neck
Describe which regions of the body drain lymph into which duct
The lymphatics from the top right of the body drain into the right venous angle.
The lymphatics from the rest of the body drain in through the thoracic duct
