Cardiovascular System Flashcards
What is the function of the cardiovascular system?
Circulate and transport nutrients,oxygen, carbon dioxide, endocrine hormones and blood cells in the plasma. Helps in homeostasis with thermoregulation, pH and disease fighting.
Key components of the cardiovascular system are:
Heart
Blood
Blood vessels
Pulmonary loop for oxygenation and the systemic loop to give oxygenated blood to the body and remove deoxygenated blood.
Is the cardiovascular system open or closed?
Closed- we don’t want an open end, all the blood would leak out.
Why are erythrocytes bi-concave?
Allow oxygen transport on haemoglobin.
Need to be squishy to fit through small capillaries.
What is the circulating blood volume?
5 litres
How much of blood is plasma and how much is erythrocytes?
3L plasma
2L RBCs
What percentage of circulating blood is in the veins?
65%
What contains the smallest proportion of our blood?
Capillaries 5%- but surface area is absolutely huge
What percentage of blood is in heart and lungs?
20%
What carries 10% of blood volume?
Arteries
What to systems compete in a cut To maintain haemostasis?
Pro-coagulant
Anticoagulant
Which side of the heart is low pressure circulation and thus is more fragile?
The right
What is bridging on coronary arteries?
In systole the left anterior descending coronary artery gets squished but then recoiled 0.13 second later- thankfully or the heart it supplies would infarct if this artery didn’t have this flexibility.
What is an end artery?
Terminal artery supplying the blood to a part of the body with no alternative route.
Why does a heart attack hurt?
Blood supply interrupted -.> hypoxia -> nerve detect hypoxia and give pain to tell you it’s in trouble -> ischaemia
Give 4 examples of end arteries then give the absolute best example.
Splenic artery
Coronary artery
Cerebral artery
Renal Artery
Central retinal artery- no other supply, vision lost in classical form and its permanently lost.
What’s artery narrowing called?
Stenosis
What’s a thrombus?
A clot?
What’s an embolus?
Something in the circulatory system that may or may not be a derivative of blood that has moved in the circulation.
What do the heart valves prevent?
Regurgitation of the blood
What are the two main arteries that supply the heart and where is their route?
Route in aorta and split to left and right coronary arteries.
Compare side effects of disturbance of blood supply to the right and left side of the heart?
Right- electrical problems
Left- mechanical muscle issues
What is the natural pacemaker where is it found and what does it do?
SAN (Sino Atrial Node) in the right atria that starts the action potential in the heart.
Why is the atria ventricular node called what it is?
It’s positioned between the atria and ventricle bulging from the septum in the right atria.
Why do you need two nodes and pause between them firing?
What is the clinical condition when this communication and delay is stopped?
Stop contraction being simultaneous we need atria ventricular delay at the AV node.
Ventricular Fibrillation
Name the branches of the aortic arch.
The aortic arch which divides into:
- Brachiocephalic trunk which divides to the subclavian artery and the right common carotid artery.
- The left common carotid artery.
- The left subclavian artery
What is the pressure in the aorta in systole on average in a healthy young adult?
Systole- heart contracts and 120mmHg in aorta
Is the tunica media thicker in the arteries or veins?
Arteries- they need thick muscular walls
What is the pressure in the aorta in diastole and where does it come from if the heart is relaxed?
70-80mmHg
Aorta wall recoiled maintaining reassure on the blood and moving it toward heart and smaller BVS. Elastic arteries act as pressure reservoirs and are called capacitor vessels because they store elastic energy from systole and become auxiliary pumps in diastole.
Where is the natural weak point of the cardiovascular system that is prone to aneurysm?
Infrarenal abdominal aorta
How do blood vessels contract?
Tunica adventitia has fenestrations that receive the noradrenaline signalling and transport it to the external tunica media which depolarises some of the superficial smooth muscle. The gap junctions propagate this depolarisation through the tunica media smooth muscle.
A ring of smooth muscle fibres around a terminal arteriole at the junction with capillaries is called a?
Pre capillary sphincter - controls blood flow to capillary bed.
Where in the body needs a protective mechanism for blood supply?
The brain 750ml/min
What needs more blood in exercise?
Heart, Skin and skeletal muscle.
What makes a capillary?
Single layer of endothelium and a basement membrane.
How do you remember how the heart sits in the body?
I am RIGHT at the FRONT, I have been LEFT at the BACK
Right side of heart front left is at the back
Why are veins called capacitance vessels?
Ability of the blood vessel to increase the volume of blood it hold with out the pressure increasing. This is inversely proportional to elasticity.
What is the primary pump for venous blood return?
Skeletal muscle contraction from calf muscle contraction.
What is the secondary venous return pump?
Respiration, breath in gives negative throacic pressure causing blood to rush back to the right atrium in the thorax.
Venous hypertension form failure of the calf muscle pumps leads to?
Venous ulceration
What position requires venous pump pressure correction?
Standing up. Venous pressure would go up in the legs if the pumps didn’t take effect.
If the calf muscle doesn’t pump the blood back up you get too much of the circulating blood volume in the legs and the brain temporarily gets a bit starved. You faint at this point so to encourage venous report stay supine with legs slightly elevated.
