cardiovascular system Flashcards
main characteristics of arteries
- thick muscular walls
- lumen changes in size
- no valves
- carries blood away from heart
why does the lumen change size in arteries?
to maintain blood pressure
main characteristics of veins
- contains valves
- thinner walls
- located closer to the surface of body
- carries blood back to the heart
heart structure
4 chambers
top chambers - atria
bottom chambers - ventricles
right hand side- deoxygenated blood to the lungs
left hand side- oxygenated blood around the body
3 layers of tissue: epicardium, myocardium + endocardium
blood pressure definition
force applied to a unit area of blood vessel wall by its contained blood. It has a systolic and diastolic
normal blood pressure of a healthy adult
120/80
normal resting heart rate range of an adult
60-80 bpm
atherosclerosis
arteries become marked, hardened and thickened, losing elasticity.
myocardial infarction
the death of an area due to interrupted blood supply. the lack of oxygen is so severe the tissue dies.
angiography
how we diagnose and treat narrowing vessels
coronary angiography
1.determine location and severity of blocked coronary artery
2. contrast media is injected (+ clot dissolving medication) through a catheter in the femoral artery up to the coronary artery
3. X-ray is used to create images of the blocked vessels so can be treated or bypassed with the use of a stent
angioplasty
procedure used to dilate artery and restore blood flow, also used to determine location of stenosis
pacemakers
sends electrical impulses to the heart to ensure correct rhythm, then follow up x-rays are performed post insertion to check positioning of leads
bradycardia
pacemaker for people with a slow heart rate
tachycardia
pacemaker for people with a fast heart rate
pulmonary embolism
prevents blood flow to the lungs
Aneurysms
thick, weakened section of arterial or venous wall that bulges out. Ultrasounds are used to determine positioning and size of aneurysm
Types of aneurysms
Saccular- one side of arterial wall
fusiform- bulging in the entire circumference
Embolization
Treatment that stops the blood flow to an abnormal vessel
Haemostasis
The process of the stoppage of bleeding
cardiomegaly
an enlarged heart
dextrocardia
a congenital condition where the heart is on the right side instead of the left
cardiac output
amount of blood pumped out by ventricles in one minute
what should the CTR be?
2:1
systole
the phase of heartbeat where muscle contracts
diastole
periods of relaxation
intrinsic control (cardiac cycle)
spreading events are coordinated by specialised myocytes that have unstable membrane potentials
what is the most unstable membrane potential?
sinoatrial node
sinoatrial node function
initiates the start of the cardiac cycle
what is the primary sensory receptor in the cardiac cycle?
baroreceptors
baroreceptors function
maintains pressure within our body, respond to the stretch of blood vessel
chemoreceptors function
help to match cardiac output to rate of ventilation
receptors for hormonal control
adrenalin and noradrenalin
where is adrenalin released in the cardiac cycle?
from the blood
where is noradrenalin released in the cardiac cycle?
from the nerve endings
what are the two measures of outputs in the cardiac cycle?
stroke volume and cardiac output
stroke volume definition
the volume of blood leaving the heart each beat
cardiac output definition
the volume of blood leaving the heart per minute ( 5L at rest)
eq: cardiac output = heart rate x stroke volume
preload definition
degree of stretch on the ventricles before they contract from blood returning to the heart
afterload definition
degree of stretch of the ventricles before they contract from blood leaving the heart
what factors affect contractility?
- alignment of actin and myosin
- removing tropomyosin
names of the atrioventricular valves of the heart
tricuspid (right) + bicuspid (left)
how do valves prevent the back flow of blood?
papillary muscles contract and pull on the heart strings, this prevents valves folding back into the atria under high pressure
chordae tendineae function
prevents the eversion of the bicuspid and tricuspid valves during ventricular contraction
papillary muscle function
can resist the pressure of blood forcing valves to turn inside out when ventricles contract
what is the coronary circulation?
the chambers of the heart own blood circulation
why does the chambers of the heart need its own blood supply?
as the heart muscle is too thick to allow diffusion
why are mycoses relation on diastole for oxygen and nutrients?
as the contraction of the heart muscle during systole reduces blood flow therefore unable to remove any further oxygen and nutrients.
