Lectures 20, 21 - Circulatory System I, II Flashcards
How many times does the heart beat per year?
35 million ! 👅
What are the important anatomical relationships involving the heart?
Anterior - Sternocostal surface
- Sternum + Costal cartilages
Inferior - Diaphragmatic surface
List the 3 kinds of circulations and their general pathways
☆ - S, P, C
- Systemic Circulation
Heart -> Body Tissues -> Heart - Pulmonary Circulation
Heart -> Lungs -> Heart - Coronary Circulation
Heart -> Heart muscle -> Heart
List the layers of the pericardium in order (superficial to deep)
- Fibrous
I - fused - Serous
- Parietal
- Pericardial cavity
- Visceral
- Heart wall
What are the three branches of the aortic arch from left to right?
- Brachiocephalic Trunk
- Right common carotid
- RIght subclavian - Left Common carotid artery
- Left subclavian
What are the three layers of heart tissue
- Epicardium: Same as visceral pericardium
- Myocardium: Heart muscle tissue
- Endocardium: Smoothin, thin lining of the heart chambers, minimizes surface friction
Explain the cardiac conduction pathway
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- Bundle of His
- RIght and left bundle branches
- Purkinje fibres
List the functions of blood vessels (5)
- Transports blood
- Transport nutrients and oxygen
- Removes waste like CO2
- Fight disease (WBC transportation)
What are the three major layers of blood vessels?
- Tunica externa
- Tunica media
- Tunica intima
What are the two main functions of tunica intima?
- Helps blood flow (reduces friction, direct contact with blood)
- Secrete mediators that influence constriction
What kind of tissue is the endothelium of tunica intima?
Simple squamous epithelium
List the three main layers of tunica intima from deep to superficial
- Endothelium
- Basal lamina
- Internal Elastic Lamina (IEL)
What unique feature does the basement membrane of tunica intima have that allows for stretch and recoil
- Collagen fibres that provide support, allow for stretch and recoil
Function and features of the internal elastic lamina
- Thin sheet of elastic fibres
- Facilitates diffusion into tunica media
What kind of tissues make up the tunica media?
Smooth muscle and connective tissue
What is the main function of the tunica media? How does it carry out this function?
- Site of vasodilation and vasoconstriction
- Regulates diameter of lumen
to regulate blood flow. - Produces elastic fibres for
stretch and recoil
- Regulates diameter of lumen
What is the most superficial layer of the tunica media (separates it from tunica externa)
External Elastic Lamina (EEL)
What make up the tunica externa (adventitia)?
Elastic and collagen fibres
Describe features of the tunica externa (3)
- Thickness ranges depending on where in the body
- Contains nerves and blood vessels (vasa vasorum)
- Anchors vessels to surrounding tissues
What are the 5 types of circulatory vessels?
- Arteries
- Arterioles
- Veins
- Venules
- Capillaries
Describe features of elastic arteries (5) give examples (3)
“Conducting Arteries”
- Largest in size and diameter
- Defined IEL and EEL
- Tunica media made mostly of elastic fibres
- Walls stretch to accommodate blood surges
- Aorta, pulmonary trunk, aortic branches
Describe features of muscular arteries (5) and give examples (2)
“Distributing Arteries”
- Medium sized with thick walls
- Defined IEL and weak EEL
- Tunica media made mostly of smooth muscle
- Greater capacity for constriction and dilation
- Thick tunica externa
- Brachial artery, splenic
Describe features of arterioles (5)
- Microscopic
- Thin tunica intima and IEL
- Pores in tunica intima
- 1-2 smooth muscle layers make up the tunica media
- Functions to control blood flow into capillaries
Describe features of capillaries (4)
“Exchange Vessels”
- Smallest blood vessels
- Connects arterial and venous supply
- No tunica media or tunica externa
- Functions in substance exchange
