Lecture 4- Cardiovascular system, anatomy of the heart, part 1 Flashcards
What organs does the cardiovascular system consist of? What is the basic role of each?
Heart= pump Arteries= supply take blood to target tissues from heart Veins/lymphatics= drainage, veins (blood), lymphatics (lymph fluid back into circulatory system) Capillaries= exchange between tissues and blood, take nutrients to and waste away
What are organs of the cardiovascular system made of?
Vascular tissue
What is vascular tissue made of?
- connective tissue
- cells
How does the connective tissue making up vascular tissue vary?
Varies according to where it is/ function:
- More collagen makes it strong +resistant
- More elastin makes it stretchy
What specific cell types make up vascular tissue?
- epithelia (form barriers between environments)
- Muscle
What two types of muscle are involved in the cardiovascular system?
- Cardiac for the heart walls
- Smooth for involuntary movements found in blood vessels and walls of lymphatics
What is the lymphatic system?
- It is part of the cardiovascular system
- A network of tissues, vessels and organs that work together to move a colorless, watery fluid called lymph back into your circulatory system (your bloodstream).
- It is known as a open-entry drainage system and is one way
The blood vascular system is…
- A closed supply and drainage system
- It works in a continuous loop to bring blood from heart to the target tissue and back
In a diagram red=
- Vessels that carry oxygenated blood
- This is not necessarily all arties as the vein from the lung to the left side of the heart carries oxygenated blood
In a diagram blue=
- Vessels that carry deoxygenated blood
- This is not necessarily all veins as the artery from the right side of the heart to the lungs carries deoxygenated blood (it going to get oxygenated)
How many pumps does the cardiovascular system consist of? What are their functions?
2 pumps that work in series the right side of the heart send to lungs (to be oxygenated). The left side then pumps to the rest of the body.
In a diagram green=
-Vessels transporting lymph fluid back to veins close to the heart (carrying blood back)
What are the two circulations within the cardiovascular system?
- Pulmonary circulation (heart and lungs)
- Systemic circulation (out to body)
What circulation reverses the rules of what you would typically think in terms of what vessels are carrying oxygenated and deoxygenated blood?
Pulmonary circulation. Arteries carry deoxygenated, Veins carrying oxygenated.
What vessel is associated with the supply side of the cardiovascular system?
Arteries are the only supply path go away from the heart out to organs.
How are arteries situated and what is this to avoid?
Major arteries are situated to avoid damage
eg: deep in the trunk; on flexor aspect of limbs
What is special about important structures in terms of supply?
Important structures often receive supply from two sources (two separate arteries)
eg: hand
Do arteries keep the same name at each branch?
No, change
What makes up the exchange network of the cardiovascular system?
Capillaries of varying degrees of permeability:
- Continuous (controlled ~ tight)
- Fenestrated (leaky)
- Sinusoidal (very leaky i.e. has lots of openings)
What are the three pathways for drainage in the cardiovascular system?
- Deep veins
- Superficial veins
- Lymphatics
(deep and superficial are part of the blood vascular, lymphatics are part of the lymphatic system)
Why can veins be found close to the skin surface?
They are not as vulnerable to hemorrhage compared to arteries
How does the cross-sectional area of arteries compare to veins and why?
Cross-sectional area of veins is at least twice that of arteries. This is because veins are not as pressurized so need this to shift the same volume of blood / second.
(The volume of blood arriving and leaving the heart needs to be the same)
What direction in relation to the heart do veins always carry blood in?
Towards
What direction in relation to the heart do arteries always carry blood in?
Away
What is the shape of the heart like?
Blunt, cone shaped
Pointed end - Apex (sits against diaphragm)
Broad end - Base (Towards neck)
How big is the heart approximately?
Size approximately that of a closed fist
How is the heart positioned in the chest?
- Rotated to left and titled
- This results in the base sitting at the second and third ribs. Apex is pointing outwards to mid of the left side of the chest (midclavicular line) between ribs 5 +6.
What is the PMI?(point of maximal impulse)
Where Apex points out between ribs 5+6. Bangs against that space and as a result hear the loudest heart sounds here (Apex beat)
What proportion of the heart sits on the left side of the chest?
2/3
In the heart what are the receiving chambers?
Right and Left atrium
What side of the heart receives all the deoxygenated blood?
Right
What is the general role of the left and right ventricles?
Pumping chambers
What is the interventricular septum?
Is a wall separating the left and right sides of the heart
What veins carry blood into the right atrium?
- Superior vena cava= carries blood from the head, neck chest and upper limbs
- Inferior vena cava= carries blood from below the diaphragm
- Coronary sinus= heart venous drainage
(this is all deoxygenated blood)
What is general role of heart valves?
Ensure unidirectional flow
What are the names/ functions of the heart valves on the right side of the body?
-Tricuspid valve= ensures blood only goes from atrium to ventricular chamber (can’t go back
in opposite direction)
-Pulmonary (semilunar valve)= ensures blood only goes from right ventricle to lungs can’t go back in through here
What is the flow of blood on the right side of the heart?
- In through superior vena cava, inferior vena cava, coronary sinus (deoxygenated)
- right atrium
- right ventricle
- out through pulmonary trunk (artery) to the lungs (to be oxygenated)
How many openings are there into the left atrium?
4, they are the pulmonary veins
What is the flow of blood on the left side of the heart?
- In through left pulmonary veins (oxygenated)
- Left atrium
- Left ventricle
- Out through Aorta which pumps to rest of body
Why are the atriums thin walled?
They are receiving chambers do not do much pumping themselves therefore do not require much muscle
What are the three layers of the heart wall?
- Endocardium (inner layer)
- Myocardium (muscle-makes most of the heart wall)
- Epicardium (outer layer)
What does the heart sit within? What are the two functions of this structure?
Pericardium
- Is a protective and supportive leathery sack
- Has 2 layers of serous membrane with lubricant in between. This means when the surfaces rub against each other (when heart contracts) there is no abrasion.
What layer of the heart wall are thickest?
Myocardium as pump is driven by muscle, epi and endocardium are thin.
What is the endocardium made of?
- Squamous epithelium (endothelium)
- Loose irregular fibrous connective tissue (FCT)
- (small) Blood vessels
- Purkinje fibers
What is the function of the Squamous epithelium (endothelium) found in the endocardium?
Single layer, flat cells. If blood didn’t have them it would just set (damage to them causes blood clots)
Which ventricle has the thickest myocardial layer?
The left ventricle is 3 times thicker than the right as it is pumping to entire body whereas right is just pumping to the lungs (short journey).
What is the epicardium made of?
- Visceral pericardium
- Blood vessels (large)
- Loose irregular FCT, Adipose
When looking at a diagram of an epicardium how do you tell which is an artery and which is a vein?
- Arteries have thicker walls as have high pressure
- Veins have thin walls as have low pressure
Describe the structure of the pericardium?
Folded in a U shape
- Visceral pericardium=inner part (also part of the epicardium cause on this surface)
- Pericardial cavity (potential space) with pericardial fluid = in-between
- Parietal pericardium= outermost
How many times does the blood go through the heart in a complete circuit?
Twice
What chamber is directly behind the sternum?
Right ventricle
What is the fibrous pericardium?
Heart sits on diaphragm, extra covering adheres to parietal pericardium and is called the fibrous pericardium
