cardiovascular system 🫀 Flashcards
How much blood dose the heath put out daily?
7,000L
You become unconscious of the heart stops for ….
And death in /…..
10s
4min
How much dose the heart weight?
300g
What can the valves of the heart withstand
100,000closures per day for 70-80 years
Blood volume in the pulmonary circulation
9%
% of blood in the systemic circulation
84%
How much blood is in the coronary circulation
7%
A persons blood in L is
5L
Output of blood for one pump is
5L per min
Pressure in RA
5mmhg
Pressure in RV
27mmhg
Pressure LA
8mmHG
Pressure LV
120mmhg
Peak pressure ratio LV RV
1:5
Wall thickness ration ventricles
1:3
How much of the heart lies to the right of the midline
1/3
How much of the heart lies to the left of the midline
2/3
Orientation of then apex
Points inferior and anterior to the left
What forms the right border of the heart
RA
What forms the inferior border of the heart
RV
What forms the left border of the heart
LV and partly LA and auricle
The base of the heart is
The superior border = blood vessels
What fills the pericardial space
Serous fluid
Layers of the pericardium (out to in)
Fibrous pericardium
Parietal pericardium
Pericardial space
Epicardium/visceral pericardium
Layers of the heart wall (outside it in)
Epicardium/visceral pericardium
Myocardium
Endocardium
In ventricular=blood
Aortic stenosis
Aortic stenosis is a narrowing of the aortic valve opening.
What is hypertrophy
Left ventricular hypertrophy is enlargement and thickening
Restriction of blood flow
Rheumatic heart disease is
a condition in which the heart valves have been permanently damaged by rheumatic fever.
What valves have a full ring of cartilage
Mitral and aortic valves
As both are associated with high pressure
The tricuspid ring is…
And the pulmonary ring is ….
T= incomplete ring
P= no ring
As these are associated with low pressure
However fatty ct is still present in places where rings are absent or incomplete
what does the fibrous skeleton of the heart do
provides electrical insulation at the and fibrous continuity for the leaflets of the mitral, aortic, and tricuspid valves.
Sinoatrial node SA is the
Pacemaker of the heart
SA - Atrial muscle
And speed
= atrial contraction
Speed= 0.5ms slow
Atrioventricular node
speed
= 100m/s delay so A can top up V
Speed = 0.05m/s very slow
AV bundle - purkinje fibres
Sped
- complicate and even contraction of ventricles - systole
Speed= fast 5m/s
Septum two sections =
Intra atric
And intra ventricular
Systemic Blood Circuit
84% of blood
High pressure and resistance
Drop in pressure is great across this circuit
Pulmonary Blood Circuit
9% of blood
Medium pressure and resistance
Veins carry oxygenated and arteries carry deoxygenated blood 🩸
Blood leaving the gut does not go directly back to the heart (as is the norm in the systemic circuit).
T or f
True
student was asked to explain how the outlet valves work
Following ventricular ejection, isovolumetric ventricular relaxation occurs. The pressure inside the ventricles starts to decrease. Once the pressure in the great arteries of the heart is greater than the pressure in the ventricles, blood tends to flow back towards the ventricles. As it does so, the blood fills up the semi-lunar valves (like water filling the pockets of your jeans). The valve flaps are forced together and create a seal, preventing blood from returning to the ventricles.
Elastic artery
.Many thin sheets of elastin in the tunic media
.during systole they expand and store the blood leaving the ventricle, then during diastole they push the blood out of the arterial tree by elastic recoil.
Thus they smother the pulsatilla flow of blood leaving the ventricles
Muscles artery
Lots of smooth muscle in the tunica media
Distraction of blood around the body at high pressure rate of blood flow is adjusted by using the smooth muscle to vary the radius of the Vessel
Arteriole
They have a thick muscular wall relative to size between 1-3 layers of smooth muscle.
Control blood flow into the capillary.
Constriction determines total peripheral pressure resistance
Capillary
Thin walled vessels, single layer of endothelium with external basement membrane diameter of one red blood cell,
Gas exchange
Venue
Small made of endothelium and ct larger ones have 1 layer of smooth muscle.
White blood cells leave the blood here
Veins
Thin walled and not a lot of ct have valves to stop back flow,
Stores blood
Low pressure
Cardiac Output can be calculated as:
CO = HR x SV
Stroke volume can be calculated as
SV = EDV - ESV
Preload
is a term which describes the stretch applied to cardiac muscle fibres prior to contraction.
When we sit still, the venous return to our heart increases because the relaxed muscles no longer resist the return of blood to the heart”
F/t
False
Cardiac reserve
is the heart’s ability to increase cardiac output to meet metabolic requirements during exercise
Afterload
is a measure of the amount of pressure that must be overcome before the aortic valve can open. An increase in afterload causes stroke volume to decrease.
Factors affecting inotropy
HR
Afterload
Sympathetic activation
Parasympathetic activation
The Frank-Starling law of the heart can be summed up by saying:
The more ventricular muscle cells are stretched, the more forcefully they contract
Sylvia makes a resolution to begin an exercise program after a few years of being physically inactive. She tells you that she wants to make her heart “beat as fast as it can” during exercise. Why is this potentially a bad idea for Sylvia?
At very high heart rates, stroke volume is decreased, this can result in a decrease in cardiac output.
what function does the heart serve?
Demand Supply →
Oxygen use Oxygen demand
→
Cardiac output (CO)
the volume of blood ejected into the aorta per minute (mL.min-1)
The more blood that returns to the heart during diastole, the more blood is ejected during the next systole.
:)
2 types of mechanisms by which the stroke volume is regulated.
instrinsic regulation= degree of stretch at end of diastole.
extrinsic regulation= activity of the autonomic nervous system and the circulating levels of various hormones.
Increased stretch of cardiac muscle =
more forceful contraction.
stroke work
work done = change in pressure x change in volume,
work performed by the heart each time it beats is given by the area of the pressure-volume curve for ventricular contraction.
Contractility
the stroke volume increase when a postive inotropic agent is present. These agents often promote Ca2+ inlow during cardiac action potentials, which strengthens the force of the subsequent muscle ibre contraction.
What are the valves in veins called
Bicuspid
How much blood 🩸 vol is in the systemic
And how much is in veins and artery
A= 13% V= 64%
Tissue fluid
extracellular fluid which bathes the cells of most tissues, arriving via blood capillaries and being removed via the lymphatic vessels.
arteriosclerosis
Arteriosclerosis occurs when the blood vessels that carry oxygen and nutrients from your heart to the rest of your body (arteries) become thick and stiff — sometimes restricting blood flow to your organs and tissue
coronary artery is narrowed to about 20% myocardium supplied by the diseased artery runs low on oxygen
Causes (ischemia) causing chest pain (angina)
. Severe ischemia results in death (infarction) of a local area of myocardium.
anastomoses
artery-to-artery junctions
Blood from coronary vines drain into..
RA
