Cardiac Anatomy and Physiology 1 Flashcards by Faith Taws

What is the function of yellow epicardial fat?

protection

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Where is your heart located?

inside the medium steinum, sits on the diaphragm
2/3 left and 1/3 right

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what is the function of the pericardium?

-bag for life
-visceral, fiborous
-protects the heart from movement, heat, infection

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structure of endocardium

layer of simple squamous epithelial cells- cover the internal heart lining

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What is the function of the myocardium?

-contractile element
-fibres overlap, pull together to contract when they are stimulated

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CO equation?

Co (L/min) = HR (bpm) x SV (ml)

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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

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What’s ventricular depolarisation?

-QRS
-Purkinje fibres depolarise constituting ventricular depolarisation

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Describe ventricular repolarisation

T wave
-smaller in amplitude and slower than depolarisation

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What does the left bundle of his bifurcate into?

-anterior
-superior
-posterior
-inferior
-fasicles

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What does the PR interval on an ECG represnt?

AV node

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How does the heart depolarise?

inside out
endocardial to epicardial

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What’s special about the dense fibrous ring?

inert

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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

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What’s the P wave in the SA node?

atrial depolarisation

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What the unit of pressure?

mm of Hg

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What is the role of calmodulin?

a protein that regulates and activates downstream kinases involved in regulating calcium signalling

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What does automaticity mean?

elements in the heart can spontaneously depolarize

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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+

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Describe action potential phase 1

-incomplete beginning of repolarisation
-fast Na+ channels close
-a transient outward potassium current is activated

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What is the function of intercalated disks?

strength
interconnecting lattice

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Describe action potential phase 0

-depolarisation
-cell driven to threshold by stimulus
-rapid influx of Na+ via sodium channels
-produce rapid depolarisation

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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

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list the unique features of the cardiac muscle

-striated
-intercalated disks
gap junctions
-bi-nucleated

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does the LV have a moderator band?

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?

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?

Which is the most anterior valve?

Where is the ostia of the coronary sinus?

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?

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?

aWheres the cristae terminales?

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