Lecture 1: Intro lecture Flashcards
What three things are involved in the heart acting as a pump?
excitation
contraction
relaxation
What are the two types of things that control how the heart works as a pump?
intrinsic and extrinsic factors
What are the four intrinsic things that affect the heart acting as a pump?
heart rate
Frank-Starling
Wall stress
Contractility
What are the two extrinsic things that affect the heart acting as a pump?
Hormones
Nervous system
What are the different vessels?
Arteries
capillaries
veins
What happens at the capillaries?
tissue perfusion
What are the two types of things that control the blood vessels?
intrinsic and extrinsic factors
What are the three intrinsic factors affecting the blood vessels?
endothelium
myogenic response
metabolic factors
What are the two extrinsic factors affecting blood vessel?
Barroreflex
haemorrhage
What are the different types of blood vessels in order away from the heart?
Arteries Arterioles Capillaries Venules Veins
How much blood is there circulating around the body?
4-6L blood
What are the three purposes of the cardiovascular system?
- to have adequate supply of oxygen and nutrients
- to remove unwanted metabolic by-products (CO2 and H+)
- transport of substances such as drugs and hormones and heat
Why is diffusion not good enough?
Because it is too slow
When is diffusion necessary?
over short distances such as when exchanging in the lungs and tissue
When do we need bulk flow of blood?
to get it around the body
The cardiovascular system is two loops in _________
series
What is the purpose of the series loop of the system?
quick delivery to the capillaries
optimal exchange at the capillaries
quick return to the lungs
What are the names of the two circuits that make up the cardiovascular system and what do these each contain?
- pulmonary system which contains the heart and lungs
- the systemic circuit which goes to the rest of the body
What surrounds the heart and what is the purpose of this?
- the pericardium
- this contains water which protects the heart by cushioning it and also stops it sticking to other organs
In each of the systemic and pulmonary circuits there is a _________ loop
parallel
What is the heart made of?
cardiac muscle cells (myocardium)
Which has thicker walls, the ventricles or the atria?
the ventricles
Which is at the bottom of the heart the atria or the ventricles?
the ventricles
Which is thicker, the right or left ventricle?
left (on the right in diagrams)
__________ rings contain valves
fibrocartilaginous
What are the two types of valves and where are these located?
The atrioventricular valves which go from the atria to the ventricles and the semilunar valves which go from the ventricles exit the heart
What are the two types of atrioventricular valves called and where are these located?
- mitral/bicuspid valve on the left side of the heart
- tricuspid valve on the right side of the heart
What are the two types of semilunar valves and where are they located?
the aortic valve which goes from the left ventricle to the aorta
and the pulmonary valve which goes from the right ventricle to the pulmonary artery
What is the purpose of the valves?
uni-directional blood flow
The opening/closing of valves is _________ and is dependent on what?
passive
pressure
Describe a cardiac muscle cell (5)
- striated due to lots of sarcomeres
- T-tubules are invaginations of the cell membrane
- sarcoplasmic reticulum for Ca2+ store
- multi nucleated
- mitochondria for ATP for contraction
How is the cardiac muscle attached together?
they are tightly coupled together via gap junctions within intercalated discs
What is the purpose of the cells being held together by gap junctions?
for electrical coupling so there can be rapid movement of ions so that all the cells can contract at once
What are the two physiological factors of the CVS?
cardiac output and peripheral resistance
What are the two physical factors of the CVS?
arterial blood volume and arterial compliance
What do these two types of factors affect?
arterial blood pressure
MAP =
CO x TPR
mmHG =
Lmin-1 x (mmHg/L/min)
What is CO?
amount of blood leaving the heart per minute
The same amount of blood leaves what?
the left and right side of the heart (but the pressure is not the same)
What is TPR?
How difficult it is for the blood to move around the body
CO =
SV x HR
What is SV?
the volume of blood ejected from either ventricle
What affects the TPR?
the raduis of the blood vessels
When is the pressure in the heart low?
when it is filling
Where is there the most extreme fluctuations in pressure?
in the ventricles
When is the pressure in the ventricles really high?
when they are contracting
There is a highly pulsatile change in the pressure in the ________-
heart
When the blood is ejected into the blood and aorta and arteries, the pressure at diastole is
much higher
The pulsatile wave dissipates going into the
arterioles and pressure decreases
Where is the pressure low and non-pulsatile?
in the capillaries, venules and veins
How do the arteries reduce pulsatile pressure?
Because of their elastic nature:
when the blood is pumped into the arteries, the elastic walls stretch and store energy and then during diastole (relax), and the arterioles control and push the blood away
