Lecture 4: ANATOMY OF THE HEART, PART 1 Flashcards
What is the cardiovascular system made up of?
Organs
What organs is the cardiovascular system made up of?
The heart, arteries, veins/lymphatics and capillaries
What is the role of the heart?
Pump
What is the role of the arteries?
Supply
What is the role of the veins/lymphatics?
Drainage
What is the role of the capillaries?
Exchange
What are the organs made up of?
Vascular tissue
What is vascular tissue made up of?
Connective tissues and cells
What do the cells consist of?
Epithelia and muscle
What do veins do?
Carry blood away from the capillaries
What do capillaries do?
They are thin and exchange nutrients and gases in the blood to the target tissues
What systems make up the cardiovascular system?
The blood vascular system and the lymphatic (vascular) system
How is the blood vascular system described?
A closed supply and drainage system (continuous loop)
How is the lymphatic (vascular) system described?
An open entry drainage system (one way)
What are the two circulations in the blood and lymph vascular systems?
The pulmonary circulation and the systemic circulation
What happens in the pulmonary circulation?
The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs for reoxygenation
What happens in the systemic circulation?
The left side of the heart receives oxygenated blood from the lungs and pumps it to the rest of the body
What happens with lymph?
Lymph which has left the capillaries and accumulated goes into the lymphatics and is returned to the vascular system. It passes lymph nodes which air present for immune surveillance
What is the supply path?
Arteries only
Where are major arteries situated?
To avoid damage (deep in the trunk, on flexor aspects of the limbs)
What do important structures often receive?
Supply from two sources - two separate arteries (hands and brain)
When do arteries change their name?
At each major branch
What is found in the exchange network?
Capillaries of varying degrees of permeability
What are the three types of capillaries?
Continuous, fenestrated and sinusoidal
How permeable are continuous capillaries?
Controlled (tight)
How permeable are fenestrated capillaries?
Leaky
How permeable are sinusoidal capillaries?
Very leaky
What are the 3 pathways for drainage?
Deep veins, superficial veins and lymphatics
What do deep veins typically have the same name as?
Arteries beside them
Where are superficial veins found?
Just below the dermis
How do veins pump blood?
At low pressure and low velocity
How do arteries pump blood?
At high pressure and high velocity
How does the cross-sectional area of veins and arteries compare?
The cross-sectional area of veins is at least twice that of arteries
Why is the cross-sectional area of veins twice arteries?
So the same volume of blood can be shifted per second. Supply = drainage
What is the shape of the heart?
It is a blunt, cone shaped organ
What is at the inferior end of the heart?
The apex
How is the apex described?
Pointed
What is at the superior end of the heart?
The base
How is the base described?
Broad
What does the heart sit in?
The mediastinum
How is the heart positioned?
It is rotated to the left and the base tilted posteriorly to bring the right side of the heart to the anterior and the left side of the heart posterior
How much of the heart sits to the left of the midline?
Two thirds
Where is the base of the heart positioned?
Between ribs 2 and 3
Where does a line from the middle of the clavicle (midclavicular line) reach?
The apex between ribs 5 and 6
Where can the point of maximal impulse (PMI)/apex beat be measured?
Where the midclavicular line meets the apex
What is the size of the heart?
Approximately the same as a closed fist
What does the superior vena cava do?
Brings deoxygenated blood from the head, neck, chest and upper limbs to the right atrium
What does the inferior vena cava do?
Bring deoxygenated blood from everywhere below the diaphragm to the right atrium
What enters the right atrium through the coronary sinus?
Venous blood from drainage of the heart
What do valves do?
Stop blood travelling backwards and insure unidirectional flow
How many pulmonary veins are there?
4 (2 left and 2 right)
What do the pulmonary veins do?
Bring oxygenated blood from the lungs to the left atrium
What are atria?
Thin walled receiving chambers
What does each side of the heart have?
An atrium and a ventricle
What are the methods of entry into the right atrium?
Superior vena cava, inferior vena cava and coronary sinus
What valve is between the right atrium and ventricle?
Tricuspid valve
What is between the right and left ventricles?
The inter ventricular septum
What is the first blood vessel in the systemic circulation?
The aorta
What valve is between the left ventricle and the aorta?
The aortic (semilunar) valve
What are the layers of the heart?
Endocardium, myocardium and epicardium + pericardium
What is the endocardium?
The layer within the heart
What is the myocardium?
The muscle within the heart
What is the epicardium?
The layer upon the heart
What is the pericardium?
The sac the heart sits in for pumping without damage
What makes up most of the heart walls thickness?
The myocardium
What part of the endocardium lines the border with the heart chamber?
The squamous epithelium (endothelium)
What does the squamous epithelium (endothelium) do?
It is thin flat cells which forms exchange surfaces and prevents blood clotting
What is also in the endocardium?
Loose irregular fibrous connective tissue (FCT), small blood vessels and purkinje fibres
What does the loose fibrous connective tissue (FCT) do in the endocardium?
Support the endothelium
What is the thickness of the left ventricle?
1.5cm
What is the thickness of the right ventricle?
0.5cm
Why is the right ventricle much thinner than the left ventricle?
Because it is a much shorter journey to the lungs than to the rest of the body
What does the left ventricle need to do?
Produce more force which requires more muscle (myocardium)
The volume of blood pumped from each ventricle is…
still the same per contraction
What makes up the epicardium?
The visceral pericardium which is at the border of the pericardial space, large blood vessels and loose irregular FCT (adipose)
What does the pericardium provide?
A protective layer
The pericardium is …
non-stick for pumping without damage
Where is the visceral layer of the pericardium?
Touching the heart
Where is the parietal layer of the pericardium?
Outside
What is between the visceral and parietal layers of the pericardium?
The pericardial space which has fluid within it for lubrication
What is the pericardium described as?
A serous membrane (continuous)
What does the pericardium consist of?
Fibrous pericardium, parietal layer, pericardial cavity and visceral layer
What is the visceral layer part of?
The pericardium and the heart wall
