Cardiovascular system and anatomy of the heart Flashcards
Components of the cardiovascular system
Organs
- Heart
- Arteries
- Veins
- Capillaries
- Lymphatic system
What are organs made of
Vascular tissue i.e connective and cells
the Cells are made of epithelia and muscle
Heart…
Is the the pump
Arteries
Carry pressurized blood away from the heart
Capillaries
Facilitate the exchange of nutrients between tissues and is the reason why the system exists
Veins
Take deoxygenated and nutrient exhausted blood back to heart
Lymphatic
Where the fluid from the blood is drained and then redrained (idk a word for this)
Blood vascular system
A continuous system i.e a closed supply and drainage system
Lymphatic system
A one way system i.e an open -entry drainage system
It drains the fluid that scapes the caps, joins larger vessels and reunites with the blood again in the heart
Structure of the lymphatic system
Porous set of capillaries that surround the blood caps that drains fluid and redrains it to prevent the tissues from swelling up
Pulmonary circulation
Deox blood from RHS –> lungs –> reox –> LHS
Lymphatic system also drains on RHS and rejoins with veins on RHS of heart
Systemic circulation
LHS –> to the body tissues where Gas exchange occurs –> RHS
What is the only supply path?
Arteries
Why are major arteries situated deeply?
A is v pressurised so situated deep in the trunk, back of knee, flexor aspects of limbs, to protect them
Why do major structures have more than one supply?
eg the head has 4 so that if one is compromised, the others will continue the supply
What are the 3 degrees of the exchange network aka capillaries?
Capillaries of varying degrees of permeability
* Continuous (controlled ~ tight)
* Fenestrated (leaky)
* Sinusoidal (very leaky)
Why are there diff degrees of leakyness
Depends on how the tissue wants to manage its supply by changing the lining of the epitheleum
Where is the pressure the highest?
The supply path i.e the arteries
Where does the pressure and velocity first drop for a good exchange?
The capillaries
Where is the pressure the lowest and the CSA twice that of the arteries?
In the drainage system
Drainage system
- Deep veins
- Superficial veins
- Lymphatic system
Deep veins
Run alongside the supply arteries and is also deep, runs in the opp direction
Superficial veins
Eg the hands, big veins with low pressure so no risk of bleeding out if cut
The hands have small arteries
Lymphatic system
Captures any fluid that leaves the caps and redrains it
Shape of the heart
A blunt cone
What is the broad end of the heart called?
The base
What is the pointed end of the heart called?
The Apex
Where does the heart lie?
In the midiastinum (cavity between the two pleural cavities)
Size of the heart
Loosely closed fist on the sternum
Where is the base of the heart
At the 2nd/3rd rib
Where is the Apex
In the intercostal space between the 5th and 6th rib after going to the midclavicular line
Where is the heart the loudest?
At the Apex peak, can also see the heart moving and pushed fully against the chest wall in a lean individual
Position of heart from a transverse slice
- 2/3 to the left from the midline
- Pushed against the pleural cavity
- Base is tilted posteriorly to the left
- Apex points anteriorly
Right pump
From systemic circuit –> right atrium (receiving space of deox blood) –> right ventricle –> pulm circuit
Left pump
From pulm circuit –> left atrium (receiving space of ox blood) –> left ventricle –> systemic circuit
How does deox blood travel?
- Superior vena cava - from head, upper limbs, chest, neck
- Inferior vena cava - Below the diaphragm
- Coronary sinus brings blood that supplies the heat itself
- Right atrium –> tricuspid valve –> right ventricle –> pulmonary valve –> pulmonary artery
How does ox blood travel?
Left and right pulm veins + 2 more veins (4 pulm veins in total) –> valve –> left atrium –> bicuspid valve –> left ventricle –> Aorta
The atria are…
Thin walled as they do not do a lot of work, just receive the blood
3 layers of the heart
Endo
Myo
Epi cardium
What is the pericardium
Around the heart, a bag of connective + epithelial tissue
What is the function of the pericardium
- Provide an oily surface that the heart beats againts i.e lubricated to prevent abraision
- Protects from external injury
What does the endocardium consist of
- Squamous epithelium (endothelium)
- Loose irregular fibrous connective tissue (FCT)
- (small) Blood vessels
- Purkinje fibres
What does endothelium do?
-Lines all structures of the cadiovas system
- Prevents the blood from hitting tissues and clotting i.e it provides a smooth surface
What are Purkinje fibres
Electrical pathways of the heart (NOT nervous tissue)
Diff in myocardial thickness
Left is 1.5cm - thicker to pump the blood around the body
Right is 0.5cm - to pump blood to the lungs
Parts of the epicardium
- Visceral serous pericardium i.e part of both epi + peri
- Blood vessels
- loose regular FCT, adipose tissue
How does the percardium form
During embryo development, serous mem is formed around the heart
- Like a balloon, the mem adhering to the heart is the visceral mem and to the cavity is the parietal mem, connected to fibrous pericardium like a tough leathery bag
- the space in between is the pericardium cavity with pericardial fluid
What does the loose Irregular FCT do
Scaffold for the blood vessels to run through in the epicardium
What is the fibrous pericardium
A tough leathery bag that is thin but v strong and made of lots of collagen
