Body Systems L7 Flashcards
Characteristics of the heart?
- Cone shaped
- Muscular pump.
Location of the heart?
- Thorax -> mediastinum (between lungs)
- Protected -> rib cage -> between ribs 2-5
- Behind the sternum
- Left of midline
- Apex -> 5th intercostal space, midclavicular line.
What 2 structures work alongside heart?
- Fibrous Pericardium
* Serous pericardium
Functions of the Fibrous pericardium?
- Prevents overfilling of heart
- Anchors position
Characteristics of the fibrous pericardium?
- Inelastic sac -> dense tissue
- Inferior fusion -> diaphragm
- Superior infusion -> large vessels
Functions of the Serous pericardium?
Prevents friction.
Characteristics of the Serous pericardium?
- Double-layered serous membrane
- Lies -> deep within -> fibrous pericardium
What are the three components of the serous pericardium?
- Parietal pericardium
- Visceral pericardium
- Pericardial cavity
Characteristics of the Parietal pericardium?
Lines inner surface -> fibrous pericardium
Characteristics of the Visceral pericardium?
Tightly adhered -> surface of heart
Characteristics of the Pericardial cavity?
Space between parietal & visceral layers
-> Contains tissue fluid.
What are the names of the three layers of the heart, and what are they composed of?
i) Endocardium: Inner layer -> Endothelium ii) Myocardium: Middle layer -> Cardiac muscle iii) Epicardium: Outer layer -> Visceral pericardium
Outline Blood flow through heart.
- Deoxygenated blood from body tissues
- > Superior & Inferior vena cava -> right atrium
2. Right atrium
- > Tricuspid (right atrioventricular) valve -> right ventricle.
3. Right ventricle
- > Pulmonary semilunar valve -> pulmonary trunk & arteries.
4. Pulmonary trunk & arteries
- > Lungs -> Oxygenated -> Pulmonary veins.
5. Pulmonary veins
- > Left atrium
6. Left atrium
- > Bicuspid (mitral/left atrioventricular valve) -> Left ventricle
7. Left ventricle
- > Aortic semilunar valve -> aorta.
8. Aorta
- > Body tissues.
What is the ventricular septum?
Muscular tissue -> dividing heart -> right & left ventricles
What is the apex?
Pointed end of heart
State the differing characteristic between the left & right ventricles. Explain why this difference occurs.
• Left ventricular walls
Much thicker than right ventricular walls
Requires strong muscular walls -> sufficient pressure -> pump blood around body.
What is the fibrous skeleton, what is it’s function and where is it located?
• Fibrous Skeleton:
- Bands -> fibrous connective tissue -> Between atria and ventricles.
- Electrically separates atria & ventricles.
- Surrounds pulmonary trunk, semilunar & atrioventricular valves.
What is the function of heart valves?
Prevent backflow of blood
Name the atrioventricular valves
- Tricuspid (Right AV) valve
- Bicuspid/mitral (Left AV) valve
Name the semilunar valves
- Pulmonary
- Aortic
Describe the AV valves
Atrioventricular:
- Tricuspid (Right AV) valve
- Bicuspid/mitral (Left AV) valve
Between atria & ventricles
Open -> blood flow -> atria to ventricles
Anchored -> Chordae tendinae to papillary muscles.
When ventricular pressure < atrial pressure
Valve opens -> loose chordae tendinae
When ventricular pressure > atrial pressure
Valve begins to close -> pulls chordae tendinae -> papillary muscle contracts -> prevents inversion of valve -> backflow of blood.
Describe the Semilunar valves
Guard entrances -> aorta & pulmonary trunk
Open -> force of blood -> contraction of ventricles
Bloodflow -> backwards -> aorta & pulmonary trunk -> ventricular relaxation
Accumulates in cusps -> shut.
Prevent backflow of blood -> ventricles.
Where is the blood of coronary circulation delivered to in the heart? Describe what must occur for this.
- 250ml/min blood
Delivered -> myocardium -> ventricular relaxation
Name the types of
Left coronary artery (LCA)
Anterior interventricular
Circumflex
Name the types of
Right coronary artery (RCA)
Marginal artery
Posterior interventricular
Where do most cardiac veins drain & where does this empty?
- Most cardiac veins -> drain -> coronary sinus
Empties -> right atrium
What are the other types of cardiac vein (besides most common) and where do they empty?
- Anterior cardiac veins -> drain directly -> right atrium.
What is angiography?
- Medical imaging technique
Examines patency (diameter length) of vessels.
What is the function of the conducting system & what is it comprised of?
What are the function of each of these components & where are they found?
Sinoatrial (SA) node
Atrioventricular (AV) node
AV bundle (Bundle of His)
Purkinje fibres
What is an electrocardiogram?
• Electrocardiogram (ECG)
- Records electrical activity -> heart.
Where does the placenta obtain oxygen & nutrients from?
Umbilical vein
Why are there 3 shortcuts in foetal cardiac cycles? Name each of these shortcuts.
- Bypasses non-functional lungs 3 shortcuts: i) Ductus venosus ii) Foramen ovale iii) Ductus arteriosus .
What is the Ductus venosus?
A shortcut in the foetal circulatory system between
Umbilical vein -> inferior vena cava
What is the Foramen ovale?
A shortcut in the foetal circulatory system between
Right -> left atria
What is the Ductus arteriosus
A shortcut in the foetal circulatory system between
Pulmonary trunk -> arch of aorta.
Outline the cardiac cycle of a placental foetus?
. Superior & Inferior vena cava -> right atrium
2. Right atrium
-> Tricuspid (right atrioventricular) valve -> right ventricle.
&
-> Foramen ovale -> left atria
3. Right ventricle
-> Pulmonary semilunar valve -> pulmonary trunk & arteries.
4. Pulmonary trunk & arteries
-> Lungs -> Pulmonary veins.
&
-> Ductus arteriosus -> arch of aorta
5. Pulmonary veins
-> Left atrium
6. Left atrium
-> Bicuspid (mitral/left atrioventricular valve) -> Left ventricle
7. Left ventricle
-> Aortic semilunar valve -> aorta.
8. Aorta
-> Body tissues.
What changes occur during birth of placental foetus regarding the circulatory system?
What happens as a result of these changes?
- Newborn takes 1st breath
- Lungs expand
Blood rushes into pulmonary circulation
O2 levels rise
Constricts ductus arteriosus
Less blood from pulmonary trunk -> aorta
» Ductus arteriosus -> Ligamentum arteriosum
- Pressure -> Left atrium -> incr.
Foramen ovale closes
Fossa ovalis
» Foramen ovale -> Fossa ovalis - Umbilical cord tied
Umbilical vessels close
Ductus venosus fibrosis.
» Ductus venosus -> Ligamentum venosum.
State the 3 changes in structure that occur between a foetal placenta and adult mammal in regards to circulatory system,
Ductus arteriosus -> Ligamentum arteriosum
Foramen ovale -> Fossa ovalis
Ductus venosus -> Ligamentum venosum.
