CV system and its anatomy Flashcards
what is a CV system used for?
transport of O2, of CO2, of hormones and of heat
varies with tissues needs
What can peripheral vascular disease cause?
it is a peripheral artery disease and due to vasospasm and atherosclerosis inflammation
causes ischaemia
how does CVD prevalence change with age?
as you get older you have a higher prevalence of CVD
what does cardiac output depend on and how can you figure it out?
depends on
- heart rate
- stroke volume; volume pumped per beat
CO = HR x SV
what does it mean by systole and diastole?
systole is the pumping phase of the heart
-> muscle expands
diastole is the relaxing part of the cycle
-> muscle recoils
how would systolic and diastolic pressure be seen on a graph and what does this show?
systolic is the peak of the curve and diastolic is the trough
at diastolic this is when the blood is pumped out
there is a pressure gradient from arteries (ABP) to veins (CVP)
what is the relationship between cardiac output and venous return?
venous return = cardiac output
- if this is not true the system is out of balance
what does the mean ABP depend on?
- volume of blood pumped out per min
- resistance of circulation
how can you calculate the systemic and pulmonary mean ABP? how do you calculate the TPR using PVR
systemic mean ABP = TPR x CO
-> should be around 90mmHg (narrower vessels so higher pressure)
pulmonary mean ABP = PVR x CO
-> should be around 12-15 mmHg
to find TPR = 7 x PVR
what can constriction arterioles cause?
this causes the ABP to increase as ABP = CO x TPR and as arterioles constrict the TPR increases so ABP increases also
what happens when arterioles in the tissue constrict? and what occurs when they dilate?
when tissue arterioles constrict, the local resistance increases and so the total blood flow will decrease; causing pressure in capillaries to decrease
when they dilate, the local resistance decreases, total blood flow increase and capillary pressure increases
what are the types of vessels and their elastic functions?
- elastic arteries; for strength and have elastic recoil
- muscular arteries; for distribution
- capillaries; for exchange of nutrients, gases etc.
- arterioles; have varying resistance to affect ABP and the total blood flow
what is the role of venues/veins?
- determine filling of ventricles
- venues increase vein pressure causing pressure in capillary to increase => oedema
- has a reservoir function
what are the functional parts of the CVS?
- conducting part ; arteries and veins
- exchange part ; capillary bed
what is the structure of the vessel wall?
- tunica externa; collagen
- tunica media ; thick smooth muscle
- > thickest layer - tunica intima ; endothelium
- > can have valves
why does arterioles have elastic tissue?
need it to expand and recoil due to the high blood pressure in the arterioles
what is capillary beds made up of?
endothelial cell layer
-> one cell thick wall; allows diffusion to cells though the extracellular space
how can arterioles control blood pressure to allow blood flow into capillary beds?
they will constrict the pre-capillary sphincters to control BP
where does the descending aorta emerge and where does it bifurcate?
emerges from the diaphragm at T12
and bifurcates at L4; where common iliac arteries are
what are the three GI tract branches?
- superior mesenteric
- inferior mesenteric
- coeliac trunk
where do each of the GI tract artery branches lead to?
- coeliac trunk leads to the foregut
- superior mesenteric artery leads to the midgut where the colon is
- inferior mesenteric artery leads to the hindgut; up to rectum and upper anal canal
what does the GI tract hepatic portal vein split up into?
it leads to liver but splits up into inferior mesenteric -> leads to rectum splenic vein -> leads to spleen superior mesenteric vein
what does the internal artery become? and where do these branches go to?
the internal iliac artery leads to the pelvic organs and it branches off into the superior gluteal artery, the obturator artery and the inferior gluteal artery
what does the external iliac artery branch off to become?
it becomes the femoral artery which leads to the inguinal ligament ; bands that connect abdomen to pelvis deep in the groin
what are the major arteries within the upper limb?
proximally you have the subclavian, axillary and brachial arteries
distally you have the radial and ulnar arteries
what are the major arteries within the lower limb?
proximally you have the femoral and popliteal arteries
distally you have the tibial arteries and the fibular artery
what are the major veins within the upper limb?
in the upper limb
superficially; cephalic vein, basilica vein which drains into the axillary
deep veins are the ulnar and radial vein and the brachial and axillary
what are the major veins in the lower limbs?
superficially; the great and small saphenous vein
deep veins are the anterior and posterior tibial and popliteal vein
these veins all drain into the femoral vein
what are deep veins?
they are vena comitantes; accompanying veins
surround the peripheral arteries
the contraction of the arteries helps with vein drainage
-> have valves
what are subcutaneous veins?
they have valves and are important in coronary bypasses
what do the internal and external carotid arteries supply?
internal carotid supplies the brain via the carotid canal
the external carotid supplies the neck and face
where do the common carotid arteries bifurcate?
they will bifurcate at superior border of thyroid cartilage
so at C3/C4 vertebrae
what is the carotid pulse lateral to?
the cricoid cartilage
C5/C6
what is the cerebral arterial circle made up of?
it is made up of the vertebral arteries and the internal carotid arteries
where do the dural venous sinuses drain?
the dural venous sinuses drain via the internal jugular vein
what is the external jugular superficial to?
the sternocleidomastoid
what does the carotid sheath contain?
it carries the internal jugular vein, the common carotid artery and the vagus nerve
the sheath drains into the brachiocephalic vein
how to know if someone is having a stroke?
if it is more than 24 hours then it is a stroke
a TIA will resolve itself within 24 hours
can lead to death
look for FAST symptoms; Face, Arm, Speech, Time
how can you find out if a patient has a stroke? what happens if they do?
CT scan
look at medical history
give an anticoagulant medication if history is clear
- if so give 300mg aspirin stat
if patient has had a stroke and has hyperlipidaemia, what medication should be given?
alteplase can be given
a secondary prevention is aspirin 300mg for 14 days
then add statins on
for patients who have had a stroke, what is the next step for treatment after aspirin and alteplase?
use aspirin and then clopidogrel 75mg after 2 weeks of aspirin 300mg indefinitely
what other treatment measures can you take for a patient having a stroke?
- oxygen therapy
- keep blood sugar at 4-11 mmol/litre
- nutrition
- rehabilitation
how to manage dysphagia and nutrition?
use SALT assessment for initial management
then rehabilitation as soon as patient can tolerate it
- help them sit up
what is the treatment for patients with TIA?
- clopidogrel 300mg loading
then clopidogrel 75mg daily and atorvastatin 20-80mg starting immediately
