5 Flashcards
How many heart valves
4
2 on each side (paired)
Valves on left side of heart
Atrioventricular valve - between atrium and ventrical
Semilunar valve - controls flow from ventricular chambers to the outflow artery (aorta)
Atrioventricular AV valves function:
Prevent blood returning to atria during ventricular contraction (when pressure goes up in ventricular chamber)
- can only go from atria to ventricle
We refer the the atrioventricular (AV) valves on the right side as
Tricuspid valve ( has 3 distinct flaps)
We refer the the atrioventricular (AV) valves on the left side as
Bicuspid (mitral) valve
Location of the 4 valves and how they look in sysitle and diastole
-pumpunary + tricuspid RIGHT
-aorta + bicuspid LEFT
Leaflets also show which one’
AV ones are bigger
Why does left chamber look smaller
Due to the rotation within the chest cavity
Operation of atrioventricular valves (Diastole and systole)
DIASTOLE
Filling phase - blood flows through valves
- blood fills chambers
- heart is pulsitile pump
- AV valve is open
SYSTOLE (ventricular)
- AV valve is close (pushed shut from the pressure so blood not pushed back the way it came)
- ventricles are contracting
- pulmonary valve (semilunar valve) is then opened
Va;ves are opened and closed during…
Different phases of the cardiac cycle
Function of semilunar valves
Prevent blood returning to ventricles, once ejected, during filling (diastole)
- once ventricles constrict and push blood into arteries - semilunar valves stop blood from flowing back after the heart relaxes
Semilunar valveless on the right side are revered to as
- pulmonary valve, 3 cusps
(Valves that opens to the pulmonary circulation)
Pushed open during ventricular systole (blood flows out of heart)
Semilunar valve on the left side is called
Aortic valve - 3 cusps
Pushed open during ventricular systole (as blood flows out of heart)
Closed as blood starts to flow back
Intraventricular septum
Seperates left and right ventricle
Papillary muscles and chordate tendineae and AV valve leaflet attachment
- papillary muscle is attached to chordate tendineae
- chordate tendineae is attached to AV valve leaflet
- papillary muscle dont pull leaflet open, they control the rate at which they close
ONLY IN AV
Why do semilunar valve not need chordate tendineae
- aortic and pulmonary valve done need them because leaflets are smaller and dint get exposed to as much pressure - support themselves
First supply path of the Cardiac circulation (ALL TLAKING)
- coronary arteries (comes from a branch of the ascending aorta, runs over pericardial layer, within a grove between the right atrium and right ventricle and run around groove into posterior of heart that will branch along the way over the epicardium and smooth branches will go down into ventricle
- heart has lots of muscle in myocardial layer - needs lots of blood supply - first branches on systemic system come back and bring oxygenated blood from aorta straight back to heart
Arteries of cardiac circulation (talking?)
- first supple is coronary arteries
- left coronary artery branches to form two big coronary arteries
1 - circumflex artery (circumflexes around to left lateral margin)
2 - anterior interventricular artery (runs over interventricular septum)
3 coronary arteries
- circumflex artery and anterior interventricular artery branch from left coronary artery
Left and right coronary are
- first branches of aorta
Small cardiac vein…
..drains terirtories supplied by right coronary artery
Great cardiac vein…
…Drains all the territories supplied by the anterior interventricular artery and the circumflex artery
Great cardiac vein and small cardiac vein drain back to…
…coronary sinus
Cardiac muscle in lingnatudanal section
Striated muscle type
Cardiac muscle - transverse section
- lumen only allows one redblood cell
Cardiac muscle
Myocardium
Features of myocardium (cardiac muscle) - in relation to other muscle types
- features of both smooth and skeletal muscle as well as cardiac muscle specific specialisations
Function of of cardiac muscle
Beating of the heart
Cardiac muscle tissue structure
- striated
- short, branched cells
- one (or occasionally 2) nuclei per cell
- central (oval shaped) nucleus
- cytoplasmic organeels packed at the poles of the nucleus
- interconnected with neighbouring cells via intercalated disks (ICDs)
Cardiac muscle - longnatudanal section
Skeletal muscle - longnatudanal
Cardiac muscle in transverse
Can’t see striations
Mitochondria in cardiac cell
- mitochondria are 20%of the volume of the cell
- very aerobic
- mitochondria tells you about aerobic dependent oxygen metabolism - tells us cardiac muscle is
- allows it o burn any fuel source - can keep beating
- irregularly branched sarcomeres
- 2% in skeletal muscle
Cardiomyocytes
Intercollated discs
Intercellular junctions - 3 different intercellular junction
3 different intercellular junctions
- Adhesion belts (linking actin to actin) ~ vertical portion (functional connection to generate force - shortening)
- Desmosomes (linking cytokeratin with cytokeratin) - stop cells pulling away during contraction
- Gap junction (electrochemical communication) ~ horizontal portion
Physically propergate by adhesion bels
Electrochemiclally propergate via gap junction
Conduction system of the heart
- its actions greatly increases the effeicny of heart pumping
- this system is responsible for the co-ordination of heart contraction and of atrioventricular valve action
- autonomic nerves alter the rate of conduction impulse generation - not nervous tissues but under nervous tone
Yap-Agee
SA node produces conduction potentials under its own tone, AV increase or decrease tone.
- spreads conduction through chambers through intermodal pathways
- internal deal pathways come back together to a unifying structure called the AV node (gate way node) - controls conduction path to the ventricles - AV node is gaitway pathway and allows the filling of cardiac cycle before sending stimulation down to muscle in ventricular stud tube for ventricular systole
- AV bundle splits onto R and L bundle branches going to R and L ventricles respectively before they end up in terminal fibres called the perkenjie fibres
- these conduction pathways are not nervous tissue but are modified cardiac muscle
Conduction vs contractile cells - transverse
Conduction cells are bloated - still have oeriferal myofibrils - used to be contractile but they differentiated
Conducation cells features
- some peripheral myofibrils
- central nucleus
- mitochondria
- glycogen
- lots of gap junctions (cos communication cells) - more abundance then desmosomes and discs as no longer contraction
- some desmosomes and few adhesion belts
- make up 1% of cardiac cells
