CARDIOLOGY - Anatomy & Mechanical Physiology (Week 1) Flashcards
Main organs of cardiopulmonary system
heart and lungs
Blood supplies body with ___________ and _________, and carries away ________ and _________.
oxygen, nutrients
carbon dioxide, waste products
Heart
A hollow muscular organ producing a pumping action causing pressure changes that circulate blood throughout body
Base vs apex of heart
Base: more flat, broad
Apex: more conical, blunt

Heart acts as a double sided pump. What does this mean?
Means that pumping occurs on L and R side, which happens when muscular walls of each heart chamber contract (squuze) causing blood to be forced out of the chambers
Heart has ___ chambers. They are:
4
Right atrium
Left atrium
Right ventricle
Left ventricle
In individuals of average height and weight, what is the size/weight/shape of the heart?
Weight: ~453g (1 lb)
Size: ~an adult’s fist (12cm long x 9 cm wide x 6 cm deep)
Shape: blunt cone
Shape of heart in taller, thinner individuals?
Shape of heart in shorter, stalkier people?
taller, thinner ppl: elongated hearts
short people: heart is of greater width
Location of the heart
- lies obliquely (slanted) in the mediastinum
- anterior to the esophagus and vertebra
- posterior to the sternum
- approx 2/3 of heart’s mass is L of midline (sternum)
- approx 1/3 of heart’s mass is R of midline
- base is directed poserior and slightly superior; lies just below 2nd rib (2nd intercostal space)
- apex is directed anterio and slightly inferior; lies just below the 5th rib (5th intercostal space) ⇒ pointed downwards towards the left

Mediastinum
place between the lungs in thoracic cavity & extends from vertebral column to sternum
How many layers make up the heart wall? list from outer layer to inner layer
1) epicardium
2) myocardium
3) endocardium
Pericardium/pericardial sac
- Loose-fitting inextensible membrane sac which encases the heart
- sac made of white firbous tissue, but lined with a smooth membrane (which has parietal and visceral layer)
Pericardium contains 2 parts. What are they?
1) Fibrous pericardium - tough, loose-fitting and inelastic sac
2) Serous pericardium (space) - thinner and has 2 layers
- Parietal layer - lining inside of fibrous pericardium
- Visceral layer - aka the EPICARDIUM - adheres to outside of the heart

Between the parietal and visceral layer of the pericardial sac contains what?
small amount of pericardial/serous fluid (10-30mL)
Function of pericardial fluid
to act as a lubricant, reducing change of friction and allowing the heart to move within the pericardial save as it beats
there is no danger of irritation as long as serous membrane remains undamaged and produces serous fluid
Epicardium
- translates to “above heart”
- outer layer of the heart
- also the same as the visceral layer of the serous pericardium

Myocardium
- literally translates to “muscle heart”
- thick middle layer of the heart
- consists of contractile cells (non-autorhythmic) and pacemaker cells (autorhythmic)
- has striated involuntary cardiac muscle cells (myocytes) joined into a continuous mass by end-to-end gap junctions (basically creating tunnels) called intercalated discs

Function of myocardium
contracts rhythmically and continuously thus providing pumping action in order for blood to circulate systemically throughout the body
What is the unique feature about intercalated discs?
These end-to-end gap junctions form discs that are electrically coupled into a single functional unit called syncytium (meaning if one feels it, they all feel it)
syncytium allows action potential (electrical impulse) to pass from cell to cell along the entire heart wall thus stimulating heart contractions

Endocardium
- translates to “within heart”
- inner layer of the heart
- made of delicate lining, endothelial tissue
- also covers the inside of the myocardium

Label all the chambers and blood vessels


Upper chambers/receiving chambers are also known as
atria
Atria are separated by
interatrial septum
Myocardial walls of each atrium are not that thick. Why is this?
Because thick walls are not required as the blood is travelling a very short distance to the ventricles
















