Cardiac Anatomy and Physiology 1 Flashcards
What is the function of yellow epicardial fat?
protection
Where is your heart located?
inside the medium steinum, sits on the diaphragm
2/3 left and 1/3 right
what is the function of the pericardium?
-bag for life
-visceral, fiborous
-protects the heart from movement, heat, infection
structure of endocardium
layer of simple squamous epithelial cells- cover the internal heart lining
What is the function of the myocardium?
-contractile element
-fibres overlap, pull together to contract when they are stimulated
CO equation?
Co (L/min) = HR (bpm) x SV (ml)
Describe the process that occurs during heart contraction
pulls in, down and twists
base descends to apex
LV and RV twists to squeeze blood out
What’s ventricular depolarisation?
-QRS
-Purkinje fibres depolarise constituting ventricular depolarisation
Describe ventricular repolarisation
- T wave
-smaller in amplitude and slower than depolarisation
What does the left bundle of his bifurcate into?
-anterior
-superior
-posterior
-inferior
-fasicles
What does the PR interval on an ECG represnt?
AV node
How does the heart depolarise?
inside out
endocardial to epicardial
What’s special about the dense fibrous ring?
inert
What does the bundle of his do?
-goes through the fibroskeleton thats electrically inert and comes down to the left and right bundles
bifurcates into left and right
What’s the P wave in the SA node?
atrial depolarisation
What the unit of pressure?
mm of Hg
What is the role of calmodulin?
a protein that regulates and activates downstream kinases involved in regulating calcium signalling
What does automaticity mean?
elements in the heart can spontaneously depolarize
Describe action potential phase 2 - plateau
-opening of slow ca2+ channels
-ca2+ moves in
-membrane permeability to k+ ions decreases
-for approx 250msec membrane potential stays close to 0mv as outflow of k+ balances inflow of ca2+
Describe action potential phase 1
-incomplete beginning of repolarisation
-fast Na+ channels close
-a transient outward potassium current is activated
What is the function of intercalated disks?
strength
interconnecting lattice
Describe action potential phase 0
-depolarisation
-cell driven to threshold by stimulus
-rapid influx of Na+ via sodium channels
-produce rapid depolarisation
What is the function of gap junctions?
-allow conduction ionic flow
-impulse in heart, gap junction provides a lower resistant pathway for ions to flow
list the unique features of the cardiac muscle
-striated
-intercalated disks
gap junctions
-bi-nucleated
does the LV have a moderator band?
No
What is the function of the moderator band?
- septum to free wall of RA
-stops Rv being overextended
-Carries conduction fibres
Name 4 types of shunts
-pathological
-physiological
-congenital
-aqquired
What is the function of the Fossa Ovalis/ pulmona valis?
allows blood to go across right to left atrium
What is the purpose of a shunt?
when we move blood form one side to the other side of the heart
Where are pectinate muscles found?
anterior portion of the right atrium
What does the coronary sinus do?
-found in the RA
-returns deoxygenated blood from the heart itself to the RA
How many pulmonary veins do we have?
4
Name the atrioventricular valves
-Tricuspid
-mitral
Name the semilunar valves
-aortic
-pulmonary
how long is the MPA (pulmonary trunk)?
4-5cm
What does bifurcates mean?
splitting
What do we call the aorta once it passes through the diaphragm?
abdominal aorta
(thoratic aorta before)
How thick are atrium walls?
1mm
How thick is he RV?
3mm
What does the myocardium mean?
heart muscle
Describe action potential phase 4
electrical diastole
heart rests
How thick are left ventricle myocardial walls?
13mm
Describe action potential phase 3
-late rapid repolarisation
-slow ca2+ channels close
-k+ channels open which increases the membrane permeability to k+ ions
-rapid diffusion of k+ due to concentration difference
What is the function of the sinus valsalva?
-first portion of aortic valve
support for aortic valve provides space behind valve leaflets when they are open
What function does the dog bone shape of the aorta serve?
cusps can’t close against the ostia
Define orifice/ostea
opening
what do we also call MV and TV?
parachute valves
name the 3 cusps in the aortic valves
-right coronary cusp
-left coronary cusp
-non coronary cusp
when leaflets in the mitral valve meet what are they called?
commisures
Name the leaflets in the mitral valve
anterior
posterior
Name the 3 leaflets in the TV
anterior
posterior
septal
how many cusps does the PV have?
3
anterior
left
right
Are MV and Tv cusps or leafletts?
leaflets
Are AV and PV cusps or leaflets?
Cusps
What does pericardial fluid do?
allows visceral and fibrous pericardium to slide over each other
-fluid dissipates heat
Intra, extra and RMP of Chloride
Intra-20
extra-10
Rmp-0
intra, extra and RMP of ca2+
intra-0.0001
extra-2.3
RMP-+120mv
intra, extra and RMP of K+
intra- 140
extra-4.5
Rmp-90MV
intra,extra,RMP of Na+
intra-10
extra-140
RMP- +67
define Stroke volume
volume of blood ejected from the heart per beat
units of intra, extra cells
mmol/litre
Which chamber has the lowest intracardiac pressure?
RA
Which is the most anterior valve?
PV
Where is the ostia of the coronary sinus?
RA
What shape is the LA?
cuboidal
What is the conduction velocity of the atrial fibres?
0.5m/s
What is the resting membrane potential of a non pacemaker cardiac cell?
-90mV
What is the most abundant intracellular ion?
k+
What is the most abundant extracellular ion?
Na+
What is the normal intracellular conc of k+?
150mmoles
What ion is responsible for activating the sarcoplasmic recticulum?
ca+
The SA node is innervated by?
SNS
What is the normal sequence of conduction?
SA
AV
HIS
BB (bundle branches)
PF (purkinje fibres)
What chamber has the pressure 5-10 mmHg?
LA
aWheres the cristae terminales?
RA
What pressure must the LV overcome to eject blood?
Afterload
What are the normal ranges for the P-R interval, QRS interval and the QT interval?
P-R - 0.12-.0.20
QRS-0.08-0.12
QT-0.25-0.45
Describe diastole stages
4
isovolume relaxation period- LV pressure drops, AV still closed
rapid inflow-AV opens, blood rushes into atria,
diastasis-filled up almost 75% of what its going to fill up to
nature contract and top up
isovolumetric contraction
Describe the events that occur in systole
-LV pressure increases
-MV shuts
-S1 heart sound- lub (contract,Av shuts)
-Semi lunar valves shut-dub
What happens during EDV?
blood left in the LV at the end of diastole
Whats afterload?
the resistancr the LV has to overcome to open the Aortic valvue
When does the valve open int he CS?
when the pressure in the LV is greater than the pressure in the Aorta