TOPIC 1: funtional anatomy of the heart

roles of circulatory system

immunity, temp regulation, hormonal role

what are the heart chambers seperated by

atria -interatrial septum

ventricle- interventricular septum

what are the heart valves called (connective tissue covered with endocardium

atrio valve- ventricular valve 1. mitral valve 2. tricuspid

semilunar valve - 1. aortic valve 2. pulomary valve - right

polumary - right

LOWER pressure - 25/8 blood flowing to and from the lungs

systemic circuit - left

higher pressure - 120/80 blood flowing to and from the tissues

key heart locations - base and apex

heart is located in mediastium

base is in line with the second rib

apex is in line with fifth intercostal space

layers of the heart

outer - fibrous pericardium - connective tissue, major artaries

parietal layer - serous pericardium - two surfaces act as lube

heart wall - epicardium, myocardium endocardium - epithelial cells, prevent blood clotting

role of cardiac skeleton

1. limits AP to specific pathways

2. reinforces myocardium

what are symptoms, cause and treatment for pericarditis - inflamation

symptom - chest pain. friction rub, cough

causes - infection, idiopathic - no cause

treatment - antibiotic, non sterile antiflamitaries

what are symptoms, cause and treatment for myocarditis

symptoms - chest pain, heart failure, arithmeas - abdormal heart

causes - infection, autoimune reaction

treatment - antiviral, antibiotic, posutve ve unotropes, diuretics

what are symptoms, cause and treatment for endocarditis

symptoms - leaky valves, heart failure, blood clotting

causes - infection and noninfection endocarditis

treatment - antibiotics or surgery

how do atrioventricular valves open

pressure gradients

coronary circulation

heart nourishment

originate at the base of the aorta

vary between individuals

corony sinus drains into right atrium

coron disease

angina pectoris

myocardial infarction

coronary arteries

left: anterior ventricular artery - interventricular sepctum and ant walls

circumflex artery - left atrium, posterior walls of left ventricle

right: right marginal artery - myocardium

posterior interventricular artery - posterior wall

sequence of AP propergation through heart

1. SA nodes generate AP

2. impulses pause at intraventricular node

3. Av bundle connects atria to ventricle

4. conduct impulse through interventricular septum

5. subendocadial conducting network depolarises contractile cells of both ventricles

how do pacemaker cells initate AP

intrinsic cardiac conducting system

pace maker potential = special properties of ion channels in sarcolema - depolarisation, Ca channels open producing AP - repolarisation - Ca channels inactivate open k channel

how are pace maker cells modulated by NTs

vagus - decrease AP, high K low Ca

sympathetic nerve - activate contractile cells of myocardium - increase AP high Na and Ca

what is normal heart rythme and names for unordinary

sinus rythme - 75BPM

bradycardio - under 60

thachycardio - over 100

how and what does an ECG measure

sum of all ap by all cells

heart rhythme, heart rate, hypothrophy, atrophy, abdormal patterns

what does p wave measure

atrial depolarisation, initated by the SA node

what causes the QRS complex

ventricular depolarisation begins at apex, then atrial repolarisation

what causes T wave

ventricular repolarisation begins at apex

3 ways cardiac muscle is different to skeletal

1. how contraction is initiated - pacemaker cells

2. how force of contraction is changed - functional synaptium

3. length of refractory period

5 stages of mechanical events during cardiac cycle

1. ventricular filling

2. atrial contraction

3. isovolumatric contraction phase - pressure on ventricle shut atria

4. ventricular ejaction phase - semilunar - into major arteries

5. isovolumetric relaxation

describe foetal vascular shunts and their funtion

ductus artirosis - plumary trunk to aorta

ductus venosus - bypass liver added to venus blood

right atrium to left through foramen ovale

name 2 spetal defects

1. atrial septal defects - ‘hole in heart’ - caused by foramen ovale not closing

2. ventricular septal defect - hole between ventricle

whats the difference between heart sounds and murmurs

heart sounds 1. closing of atrioventricular valve 2. closing of semilunar valve

heart murmurs - abdomonal - leaky or narrow valve

how are semilunar anf atrioventricular structually different

AV valves are closed by backflow of blood

semilunar valves - during ventricular diostole leaflets are fille with backflowing blod and valves close

Name the two types of cardiac myocytes found in cardiac muscle

1. pacemaker cells - autoarrythmia 1% (noncontractile, spontanteously depolarise)

2. contractile myocytes - contractile cells 99% (main responsible for hearts pumping)

what is arrythmia

abnormal heart rate

which structures contract slightly before ventricular contraction

where is the exit of the coronary sinus

right aorta

where to coronary arteries originate

base of the aorta, distal to semilunar valve

where is primary pacemaker cell loacated

in right atrium

what is the inherent heart rate of SA node AV node and ventricular pace maker

100, 50,30

resting systolic pressure of pulomary circuit is

25

Which structure delay transmission of the normal pacemaker signal in the heart prior

to it’s transmission to the ventricles?

Av node

The atria and ventricles are in electrical contact via…

Av node an AV bundle

describe microscopic anatomy

interculated discs, funtional syntium, gap juntions

describe the sinoatrial node

hearts pacemaker and sinus rythme determines HR, impulses 75X per min

describe artioventricular node

impulses is delayed 0.1 second

describe subendocardial conducting network

‘pjunke fibres’ long strands of barrel fibres with few myofibrils - depolarise the the contracile cells of both ventricles

what are extrinsic innervations of the heart:

what mechanical event lines up with peak of t wave

aortic valve shuts

3 shunts in fetal circulation

ductus venosus, foramen ovale, ductus arteriosus

What two vessels are connected together by the ductus venosus?

umbilical vein, inferior vena cava

names for altered shunts after birth

ligamentum venosum, fossa ovalis, ligamentum arteriosum

name for when bloodflow is stopped to area of heart causing ischaemia

myocardial infarction

what is it called when pericardial cavity fills w too much fluid

cardiac tamponade

Attachment sites between the transverse lines between cardiac muscle cells

intercalated discs

two features of intercalated discs

desmosomes, gap junction

how is force of contraction changed

calcium concentrations

how do you ensure heart muscle doesnt go into tentanus (remain contracted)

length of absolute refractory period

what cells are attached to SA node

pacemaker cells

all veins carry deoxygenated blood expect … all arteries carry oxygenated blood excet …

pulmonary vein/artery

what structure slightly contracts before ventricular contraction in the heart

papillary muscles

during dystole …% of ventricular filling occurs before atrial contraction

80%

how are distributing arteries subject to extrinsic control

• nerual (sympathetic nerve) or hormonal (ADH, angiotensin II, adrenaline, noradrenaline)

does atherosclerosis decrease or increase BP

increase resistance = increase resting blood pressure

what is angina

chest pain caused by poor blood flow to heart muscle

how much blood does veins store

60%