Cardivascular System - Lec 1 Flashcards
What’s the function of the circulatory system and name its subsections
Functions related to transport of blood and
the system consists of the heart and the blood vessels (conduction System)
The system achieves the function by being spilt into 2 part series, the pulmonary and systemic circulation (blood travels between these sections again and again and again)
Explain the mechanics of pulmonary circulation of blood
Function = transport blood through lungs.
Links the right side of heart (receives deoxygenated blood) with left (pumps oxygenated blood through the tissues)
The right side of the heart is the pump for the pulmonary circulation. Ie. the right side of the heart receives blood from the tissues that now lack oxygen and need to be reoxygenated (enters right side via IVC)
and so the deoxygenated blood passes through the lungs, and becomes loaded with oxygen and the CO2 is removed And then is distributed to the tissues via the systemic circulation
SOOOOO…blood comes through the systemic — pulmonary (right heart—L+R lungs) — back to the systemic (the left side of the heart)
What’s characteristic of the structures involved in pulmonary circulation
This is a low pressure system due to minimal resistance of the pulmonary vessels, and this suggests why the right ventricle has small muscle mass (as it does not develop high pressure)
- to maximise rate of diffusion between blood vessels and alveoli
- blood would go through the lungs too quickly if the pressure was too high and so might not be oxygenated efficiently
Explain the mechanics of systemic circulation of blood
Function = transport blood through to the tissues. Links the left side of heart (which pumps oxygenated blood) with right.
Left side of heart serves as a pump for systemic circulation and allows the blood to pass through tissues to unload oxygen and exchange it for CO2 (Produced due to metabolism)
SOOO… blood from pulmonary circuit (ie. oxygenated blood entering from lungs) — systemic circuit (enters the left heart and distributed to tissues around the body)
What’s characteristic of the structures involved in systemic circulation
System circuit is a High pressure system as the systemic blood vessels have high resistance and so the left ventricle has large muscle mass in order to withstand high pressure
THEREFORE LEFT SIDE OF HEART HAS HIGHER PRESSURE THAN RIGHT SIDE OF HEART
Explain the location of the Heart and the space it occupies
In mediastinum, anterior chest wall region behind sternum and suspended within the pericardial sac
1/3 lies to right of midline and the other 2/3 is found to the left
SO LESS THAN 50% OF THE CARDIAC SILHOUTTE OCCUPIES THE TRANSVERSE CHEST DIAMETER
Base of heart is at superior surface, and apex of heart is at inferior surface
- normal adult = 12.5 cm from base to apex
Name the borders of the heart with an PA view
Entire heart is rotated to left SO RIGHT SIDE IS ANTERIOR
- right atrium forms the right border in PA
- left ventricle forms left border in PA
- right and left atrium form superior border in PA
- right ventricle forms inferior border in PA
Discuss the projection done as a result of the hearts positioning in the human body
We do PA to minimise mag of heart, because the heart lies more anteriorly in thoracic cavity
CLOSER TO IR THE LESS MAG
Name the great vessels of the heart
Vessels that are located within the mediastinum and allow the DIRECT entrance and exit of the heart
Aorta Pulmonary trunk Superior Vena cava Inferior vena cava Pulmonary veins
Explain the functions of the aorta
Leaves the left ventricle
Divided into 3 parts
- ascending
- aortic arch (curves posterior over left lung - can be over to the right in a small minority)
- descending arch (slightly anterior and to left vertebral column (called thoracic aorta when in thorax and abdominal aorta when in abdomen)
Explain the functions of the pulmonary trunk
Leaves from the right ventricle
Origin of right and left pulmonary arteries
It’s attached to aortic arch by ligamentum arteriosum
Explain the functions of the superior vena cava
Enters into the right atrium
Formed by junction of brachiocephalic veins
Carries blood from thorax, head and neck
Located posterior to ascending aorta
Explain the functions of the IVC
Formed by junction of iliac veins
Ascends to the right side of the abdominal aorta
Passes through caval hiatus of diaphragm
Explain the functions of the pulmonary veins
Enter into the left atrium
It brings back blood from the lungs (the oxygenated blood)
What’s the pericardium
Made of 2 parts
- epicardium (Attaches to surface of heart)
- parietal pericardium (attaches to inner surface of pericardial sac)
These two surfaces are separated by the pericardial cavity where there’s 15-50ml of pericardial fluid
What is the pericardial sac made of?
Fibrous tissues
What’re the sulcus of the heart and name them
Sulci mark the boundaries between the atrium and ventricles and between the right and left ventricle
They contain many arteries and veins supplying myocardium (muscular tissue of heart ) and fat
- antriventricular sulcus = between atrium and ventricle
- anterior and posterior interventricular sulci = between ventricles
Name the chambers of the heart
Right atrium
Right ventricle
Lefts atrium
Left ventricle
Explain the function of the atrium
Recieve blood directly from great veins
- right atrium = receives deox blood
- left atrium = receives oxy blood
This blood flows directly through into the ventricle (most ventricular filling tends to be passive) where the contraction of the atrium allows this top up into the ventricle to occur.
The atrium are separated by the interatrial septum
There’s an extension of the atrium called the atrial appendage
What’s atrial fibrillation
The atrium isn’t contracting effectively
The effect isn’t drastic or significant
Explain what’re ventricles
Receive blood from atrium, and it pumps blood out of heart and into the arteries
Achieves this by generating pressure that is suffienct enough to overcome resistance in the blood vessels
Left v thicker than right
Name the external surfaces of the heart
Apex Base Sternocostal surface Diaphragmatic surface Pulmonary surface
Name the borders of the heart
Left border
Right border
Superior border
Inferior border
Name the regions of the atrium
Auricular walls (musculature pectinati)
Left atrial wall
Right atrial wall
Name the regions of the ventricle
Ventricular walls (trabeculae carneae)
Left and right atrioventricular valves
Chordae tendinae
Papillary muscles
Name the septa of the heart
Interventricualr septum
Interatrial septum (fossa ovalis)
Name the valves of the heart and their location and structure
Antrioventricualr valve - made of leaflets attached to papillary muscles by chordae tendinae (heart strings) that contract when closed and relax when open
- right one is called TRICUSPID
- left one is called BICUSPID
Semilunar valves (3 crescent shaped cusps, seperate ventricles from the great vessels)
- right pulmonary valve = separates right ventricle and pulmonary artery
- left aortic valve = separates left ventricle and aorta
Explain the significance of valves
They act as seals, and ensure that blood flow is unidirectional (backflow shouldn’t occur)
Thin leaflike structures that don’t contain muscle
They’re attached to walls
They open and close passively according to pressure gradients
Chordae tendinae and papillary muscles act as anchors to limit movement
What’s valvular disease?
Calcification if valves
Can lead to valve failure, therefore
- chamber of heart won’t empty properly
- chamber will contain excessive amounts of blood (causes enlarged contour)
- murmurs May be produced by regurgitation of blood through the failing of valve
Name the great vessels that enter the heart
SVC
IVF
Pulmonary veins
Name the great vessels that leave the heart
Aorta
- ascending aorta
- aortic arch and its three major branches
(brachiocephalic trunk, left common carotid artery, left subclavian artery)
- descending aorta
Pulmonary trunk
- right and left pulmonary arteries
