principles of cardiorespiratory system Flashcards
What are the 3 layers of the heart wall (outside to inside)?
- epicardium
- myocardium
- endocardium
Describe the myocardium microstructure?
- striated appearance
- intercalated discs
- branching pattern
- 1/2 nuclei per cell
Describe smooth muscle?
- not striated
- one central nucleus per cell
Describe the left lung
- 2 lobes
- oblique fissure
Describe the right lung
- 3 lobes
- horizontal and oblique fissures
What are the functions of smooth muscle?
- regulates diameter
- propels liquids and solids
- expels contents
What are the layers of blood vessels?
- tunica intima
- tunica media
- tunica externa (adventitia)
Describe the tunica intima layer of blood vessels
- lined by endothelium
- connective tissue
What is the function of the tunica intima layer of blood vessels?
reduces friction for blood flow
Describe the tunica media layer of blood vessels
- primarily smooth muscle
- connective tissue (elastic and collagen fibres)
What is the function of the tunica media layer of blood vessels?
controls size and shape of artery
Describe the tunica externa layer of blood vessels
- outer connective tissue layer (primarily collagenous)
- can contain nerves and vessels
What is the function of the tunica externa layer of blood vessels?
connects artery to surrounding structures
What is the main feature of the large elastic arteries?
tunica media contains many layers of elastin
What is the main function of the large elastic arteries?
accommodates surges in blood
Describe the large elastic arteries and some examples
- large diameter (over 10mm)
- only includes arteries closest to the heart (aorta, subclavian, common carotid arteries)
Describe the medium muscular arteries
- smaller diameter (0.5-10mm)
- most other named arteries (femoral and popliteal arteries)
What is the main feature of the medium muscular arteries?
tunica media contains a thick layer of smooth muscle
What is the main function of the medium muscular arteries?
vasoconstriction and vasodilation
Describe the small arteries and arterioles?
- small arteries = 0.3mm-0.5mm
- small arterioles = microscopic
- decreased thickness of all layers
- not normally named
What is the main feature of small arteries and arterioles?
- tunica media predominantly smooth muscle
- 1-2 cell layers in thickness
What is the main function of the small arteries and arterioles?
tonus dictates degree of filling of capillary beds
What is the main feature of capillaries?
endothelial layer only (no tunica media or externa)
What is the main function of the capillaries?
allow exchange between blood and extracellular fluid
What are the two types of capillaries?
- continuous
- fenestrated
Describe the continuous capillaries?
- uninterrupted endothelium
- most common
Describe the fenestrated capillaries?
- has pores (fenestrae)
What are the main features of veins?
- tunica media thinner
- large veins have well developed tunica externa
Describe the venous valves?
- inward projection of intima
- strengthened by collagen and elastic fibres
Where are the venous valves absent?
thorax and abdoment
What is the name of the circulation that goes to just the lungs and heart?
pulmonary circulation
What is the name of the circulation that goes between the heart and the rest of the body
systemic circulation
Describe the intercalated discs in myocardium microstructure
- have fascia adherens and desmosomes (act as anchors)
- have gap junctions (free flow of ions for APs)
Give examples of medium muscular arteries
femoral and popliteal arteries
Which veins do I need to know?
- femoral
- popliteal
- great saphenous
What factors aid the return of blood against gravity?
- valves
- arteriovenous pump
- respiratory pump
- musculovenous pump
What is anastomosis?
vein connected to vein or artery connected to artery
What are arteries with no anastomosis called?
end arteries
What are the 2 types of end arteries?
- anatomic (true)
- functional (potential)
