anatomy- heart and lungs Flashcards
circulatory and cardiovascular
circulatory- organ system transporting oxygen carbon dioxide, nutrients
cardiovascular system- heart, blood vessels, blood, lymphatic system
pulmonary circulation (lungs)
- oxygen depleted blood
- passes from heart to lungs
- returns oxygenated blood to heart
systemic circulation (rest of body)
- oxygen rich blood
-passes from heart to rest of body - returns deoxygenated blood to heart
mediastinum
super mediastinum
- upper portion T1 posteriorly- superior aspect
- lower portion- sternal angle- landmark for 2nd rib
inferior mediastinum
- anterior (fat and thymus)
- middle (heart)
- posterior (aorta, oesophages)
heart- structure, pericardium
pericardium- 2 layers
fibrous (tough outer layer which anchors heart to diaphragm). it prevents rapid over-filling of the heart but can also restrict if there is an accumulation of fluid (pericardial effusion) compressing the heart, especially its right side and reducing the cardiac output
- pericardial space, has a small amount of lubricating serous fluid which reduced friction of the layers during beating of the heart
heart structure- serous
- has 2 layers
- outer visceral layer and inner parietal
heart strucutre- cava and trunk
superior vena cava- SVC, deoxygenated blood from head and neck and upper limbs
inferior vena cava IVC- deoxygenated blood from below level of heart eg, abdomen, pelvis, lower limbs
pulmonary trunk- pulmonary arteries L/R and on to lungs
aorta
- coronary arteries
- brachiocephalic trunk (right common carotid artery (head and neck))
- left common carotid artery (head and neck)
- left subclavian artery (upper limb)
foetal circulation
- ducts venosus: allows blood to bypass liver (30% of maternal blood) to the inferior vena case, at birth this closes and becomes the ligament venosum
- foramen ovate: allows blood to flow from the right atrium to the left atrium
systemic circulation of the foetus
if blood passes into the right ventricle rather than it going to the non-functioning and breathing lungs in utero, the ducts arteriousus links the pulmonary trunk with the aorta. This allows blood to flow into the systemic circulation of the foetus
- umbilical arteries carry deoxygenated blood back to the placenta
fossa ovalis
- embryonically remnant of the patient foramen ovale in foetal life.
- this used to allow blood to flow between the right atrium and the left atrium
aortic sinuses
- dilatations just above the aortic valve. there are 3 of these and from 2 arise the left and right coronary arteries
right partial appendage
-additional part of the right atrium. this is typically used as the site for an external pacemaker to be positioned
crista terminalis
- at the opening of the right atrial appendage and is the site of origin of the pectinate muscles
musculi pectinati
allows for stretch and improve the volume of the right atrium
orifice (opening) of coronary sinus
- where the venous blood from the heart enters
pulmonary veins
2 on left and 2 on right carrying oxygenated blood to the left atrium
left ventricle
- approx 3x thicker than the right as it has to pump blood into the systemic circulation
- the right is smaller and less powerful as it pumps blood to the lungs only
heart chambers- septal defects ASD/VSD
Atrial septal defect/ventricular septal defect: present at birth. Small holes sometimes close themselves and larger one will compromise the lungs and heart due to increased blood pressure
AVSD- atrioventricular septal defect
- require surgery as it will compromise the patient leading to problems with breathing, racing heart, weak pulse and cyanosed and tiring easily.
heart valves
posterior- tricuspid (3 leaflets) and mitral (2 leaflets)
anterior- aortic and pulmonary valve
chordae tendinae
- heart strings that connect to the papillary muscles and prevent the mitral and tricuspid valves flipping back into the atria during ventricular contractions (systole)
atrioventricular valve open
1) blood returning to the heart fills atria, putting pressure against atrioventricular valves, atrioventricular valves forced open.
2) as ventricles fill, atrioventricular valve flaps hang limply into ventricles
3) atria contracts, forcing additional blood into ventricles
atrioventricular valve closed
1) ventricles contract, forcing blood against atrioventricular valve cusps
2) atrioventricular valves close
3) papillary mulches contract and chordae tendineae tighten, preventing valve flaps from everting into atria
semilunar valve
- half moon shaped structures and these are the aortic and pulmonary valves.
- these do not have chordae tendinae unlike the mitral and tricuspid valves.
- they hold the blood here to prevent back flow into the right and left ventricles
semilunar valve open
as ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open
semilunar valve closed
- as ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close
end arteries
only supply oxygenated blood to a specific portion of tissue. these vessels exist in the spleen (splenic artery), liver, intestines, ends of digits, ears, nose and penis
- in the heart, it can result in ischaemia causing collateral circulation to develop. this is new blood vessels growth to pass around the area of reduced blood supply.
conducting sysytem
sinoatrial node generates electrical signals and is the pacemaker of the heart (controls heart rate)
moderator band- allows for more rapid conduction across to the anterior papillary muscle and helps with conduction times.
purkinje fibres specialised conducting fibres, bigger than cardiac myocytes and create a synchronised contraction across the ventricles, thus maintaing our regular heart rate.
respiratory tract
function
- conduction if air
- respiration
- protection against pathogens
structure of respiratory tract
upper -nasal cavity
pharynx
larynx
lower- trachea
primary bronchi
lungs
upper respiratory tract
nasopharynx- base of skull to soft palate
oropharynx- soft palate to epiglottis (elastic cartilage)
laryngopharynx- epiglottis to where the bifurcation occurs to the oesophagus and the trachea
lower respiratory tract
right bronchus- vertical, greater diameter and shorter than left main bronchus
foreign bodes more likely to go to right broncos
- bronchi: superior and inferior lobe bronchus in both left and right lungs and in the right lung there is also the middle lobe bronchus
respiratory epithelium
- pseudostratified ciliated columnar epithelium with goblet cells
surfactant
secreted by the type II pneuomocytes and increases lung compliance and prevents collapse, or atelectasis of the lungs at the end of expiration
- produced from week 24-28, and enough production occurs by week 34 out of 40 week gestation
