Introduction to the Circulatory System Flashcards
(30 cards)
What is the Circulatory System?
- Made up of the cardiovascular system and the lymphatic system (both carry fluid)
- Distributes gases and other molecules
- Chemical signalling
- Mediates inflammation and host defence response
- Carries waste products from cells
What are the 3 main components of the Cardiovascular System?
Arterial system
Arteries carry blood away from the heart
Heart
The pump of the system
Venous system
Veins carry blood towards the heart
What are the 2 main circulations of the CVS?
- pulmonary circulation
- systemic circulation
What are the 3 layers of the heart?
What are the 4 chambers of the heart?
What are the Great Vessels of the heart?
Superior Vena Cava
Inferior Vena Cava
Pulmonary trunk
Pulmonary veins
Aorta
What are the 4 main Cardiac Valves?
ensure uni-directional blood flow
Describe Conduction System of the Heart?
- Electrical impulse starts spontaneously at sinoatrial node- Causing both atria to contract
- Travels to atrioventricular (AV) node at atrioventricular septum
- Travels down right and left bundles in interventricular septum
- Spreads out to myocardium through conducting fibres
- Causing both ventricles to contract
7 Key principles of Arteries
- Usually part of neurovascular bundle (NVB)
- High pressure
- Usually deep location compared to veins
- Round lumen
- Pulsatile
- Carry oxygenated blood
- Often divide (bifurcate or trifurcate)
‘Common’ or ‘trunk’ indicates it will definitely divide!
Name the 4 parts to the aorta
Ascending
Arch
(Descending) Thoracic
(Descending) Abdominal
How does the aorta work?
- Arterial blood enters aorta first
- Receives blood at high pressure during systole
- Its elastic walls expand under this pressure
- Elastic recoil maintains peripheral flow during diastole
Name the Branches of the Arch of Aorta
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
Basic Upper Limb Blood Supply
Basic Lower Limb Blood Supply
6 Places to Feel Peripheral Pulses
- Carotid (bifurcation of common carotid artery)
- Brachial artery (anterior to elbow joint)
- Radial artery (radial side of palmar aspect of wrist)
- Femoral artery (continuation of external iliac artery)
- Popliteal artery (posterior to knee joint)
- Dorsalis pedis artery (dorsum of foot)
What is Anastomosis?
Communications between arteries
Alternative pathway (or collateral circulation) for blood flow to supply the tissues distal to an arterial occlusion
What is an end artery?
- The ONLY arterial blood supply to a given area
- Untreated occlusion of an end artery results in infarction of its territory
8 Key Principles of the Veins
- Usually part of neurovascular bundle (NVB)
- Low pressure
- Non- pulsatile
- Carry deoxygenated blood
- Drain blood away from a territory
- Often follow arteries
- Thin walls which collapse when empty
- Have valves
Describe 3 features aiding Venous Return
Venous blood flows back towards the heart, assisted by:
Venous valves
In limb veins, valves are present to ensure unidirectional flow back to the heart against gravity
Musculovenous pump
Contraction of skeletal muscles in the lower limb
Venae comitantes
Small veins run in pairs or more with an artery in a sheath
Arterial pulsation pushes venous blood along
Describe the 2 sets of veins
Superficial veins
Smaller and run in superficial fascia
Drain into deep veins
Deep veins
Larger and run deep to deep fascia and in cavities
Describe the 2 main Venous Systems
Portal venous system
Drains venous blood from the GI tract
And associated organs
To the liver
Systemic venous system
Drains venous blood from all other organs and tissues into the superior or inferior vena cava
Function of the Capillaries
- Form extensive vascular networks (Approx. 50,000 miles)
- Lined with single layer of endothelium
- Narrow lumen only allowing one red blood cell (erythrocyte) through at a time
- Allow for exchange of gases, metabolites and waste products
Describe Lymphatic Circulation
and lymph return
- Lymphatics carry lymph through lymph nodes
- Eventually lymph is returned into the central veins in the root of the neck
Lymph from superficial lymphatics → deep lymphatics
Lymph from right lymphatic duct → right venous angle
Lymph from thoracic duct → left venous angle
Where are landmarks for auscultation of the four cardiac valves?
Aortic Valve – Right 2nd intercostal space at sternal edge.
Pulmonary Valve – Left 2nd intercostal space at sternal edge.
Tricuspid Valve – Left 4th intercostal space at sternal edge.
Bicuspid (mitral) Valve – Left 5th intercostal space in mid-clavicular line
