Vasculature Flashcards
1
Q
What are the 4 principle divisions of the aorta?
A
- ascending aorta coming off of the L ventricle and has emergence of L and R coronary arteries
- arch of aorta branching over the pulmonary trunk- brachiocephalic trunk which will then branch into R carotid and R subclavian, left subclavian, and left carotid
- descending aorta- thoracic and abdominal regions
- diaphragm divides the thoracic from abdominal
- thoracic will supply pericardium, esophagus, bronchi, diaphragm, intercostal and chest muscles, mammary gland, skin, vertebrae, and spinal cord
- abdominal will supply abdominal and pelvic viscera, lower extremities
2
Q
What are the unpaired branches off of the abdominal aorta?
A
- celiac trunk, superior mesenteric, inferior mesenteric
- celiac has 3 main branches; common hepatic artery which supplies the liver, other vessels that supply the stomach, spleen, pancreas, and duodenum
- superior mesenteric supplies pancreas, small intestine, and part of large intestine
- inferior mesenteric supplies other part of large intestine
3
Q
What are the paired arteries off of the abdominal aorta?
A
- suprarenal supplying adrenal glands
- renal arteries supply kidneys
- gonadal arteries supply the gonads
- gonadal arteries are longer in men
- 4 pairs of lumbar arteries and last pair is the common iliac
4
Q
What do the SVC, IVC, and coronary sinus drain?
A
- SVC: head, neck, chest, upper limbs
- IVC: abdomen, pelvis, and lower limbs
- coronary sinus: great cardiac vein, middle cardiac vein, small cardiac vein
5
Q
What happens at the hepatic portal vein?
A
- venous blood moving from GI organs and spleen passes through the liver before going back to the heart
- make sure there is processing of the blood before it returns to the heart
- superior and inferior mesenteric veins drain into hepatic portal vein to the liver where blood is filtered and modified/stored/detoxified
6
Q
What is a conduit vessel?
A
- transport blood to and from regions of the body
- eg. aorta, vena cavae
7
Q
Describe arteries, capillaries, and veins
A
- arteries move blood away from the heart
- arteries-arterioles-capillaries
- capillaries: site of gas and nutrient exchange, waste removal
- veins: return blood to heart
- capillaries-venules-veins
8
Q
Describe the structural characteristics of an artery
A
- pressure vessels
- tunica intima: endothelium, basement membrane, internal elastic lamina
- endothelium: smooth non-thrombogenic layer where blood flows by as it moves through the lumen
- internal elastic lamina: has fenestrae, allows diffusion across membrane, gives rise to some stretch of vessel
- tunica media: smooth muscle cells, elastic fibres, external elastic lamina
- histology section of vessel wall in tunica media, a layering is visible of smooth muscle cells and elastic tissue, extent of this layering depends on size of artery
- tunica externa/adventitia: elastic and collagen fibres, vasa vasorum, helps adhere vessels to surrounding tissues
- vasa vasorum: small network of vessels which supply the outer portions of large vessels with their metabolic requirements
9
Q
Describe the structural characteristics of veins
A
- volume reservoirs (2/3 blood volume resides here)
- presence of valves
- ensure one way flow
- tunica intima: endothelium, basement membrane
- tunica media: smooth muscle cells, some sources will say elastic tissue is present but regardless this tissue does not form elastic sheet and layering as is observed in an artery
- tunica externa: elastic and collagen fibres, vasa vasorum
10
Q
Describe the primary differences between arteries and veins
A
Anatomically:
- veins have a much thinner muscular layer and tunica externa
- veins have no elastic layers but they do have valves
Physiologically:
- veins have almost no blood pressure to resist which means the vessel wall can be much thinner and weaker
- valves are necessary to prevent backflow and assist in venous blood return
11
Q
Describe elastic arteries
A
- biggest arteries (eg. aorta), pressure reservoir
- same thickness as muscular arteries but 3x or more in diameter
- predominantly elastic tissue and smooth muscle cells
- conduct blood to muscular arteries
- must resist pressure of contractions of the heart (systole) and provide pressure between heart beats (diastole)
- tunica media is full of elastic fibres and connective tissue
- expand when BP increases and recoil when BP decreases evening out the pulse pressure
- recoil ensures continuous flow of blood
12
Q
Describe muscular arteries
A
- smaller in diameter
- predominantly smooth muscle cells
- more smooth muscle than elastic fibres
- smooth muscle responsible for vasodilation and vasoconstriction
- walls are relatively thick
- direct blood flow
- multiple branching arteries
- brachial and radial artery
- femoral and tibial artery
13
Q
Describe characteristics of arterioles
A
- resistance vessels
- arteriole is mostly smooth muscle cells because of its role in vasodilation/constriction
- contribute to resistance in system
14
Q
Describe capillaries
A
- very small (about the size of a red blood cell)
- exchange vessels, microscopic
- act as “u turn” where we go from arteries to veins
- mostly endothelial cells
15
Q
What tissue types have greater capillary networks?
A
- active tissue
- more metabolically active tissue requires more oxygen and nutrients and it produces more CO2 and waste products
- brain, heart, liver
16
Q
Describe the parts of the microvascular bed and vasomotion
A
- at terminal end of arteriole, there is a metarteriole with precapillary sphincters
- when precapillary sphincters are open, it allows blood flow through capillary bed
- at other side, there is postcapillary venule
- vasomotion allows redirection of blood from all of the capillaries to get it to the venous system quicker
- precapillary sphincters close so that not all capillaries are supplied and blood goes through a thoroughfare channel instead
18
Q
A
19
Q
Describe fenestrated capillaries
A
- fenestrations in addition to clefts
- additional areas for molecules to move through
- kidney, choroid plexus
20
Q
What is a continuous capillary?
A
- brain, lungs, muscle
- endothelial cell layer is continuous
- presence of intercellular clefts and tight junctions
- no large openings
21
Q
Describe sinusoid capillaries
A
- incomplete basement membrane
- large intercellular clefts
- larger substances need to move through these capillaries
- found in red bone marrow, liver
23
Q
What is transcytosis?
A
- vesicular transport (endo and exocytosis)
- substances enclosed by pinocytic vesicles
- large, lipid insoluble molecules
24
Q
What is bulk flow?
A
- regulation of relative volumes of blood and interstitial fluid
- pressure gradient: movement from high to low pressure
- filtration: from blood capillaries to interstitial fluid
- reabsorption: from interstitial fluid to blood capillaries (85% reabsorbed)
- passive process
27
Q
Where is protein concentration highest in the capillary? How does this affect the pressures?
A
- presence of protein doesn’t change at venous or arterial end
- oncotic pressure is essentially the same at each end
- protein of importance is albumin
- HP>OP net flow out of capillary at arterial end
- HP<op></op>
<p>-larger molecules can't move through into the interstitial space so they stay in the blood</p>
</op>
28
Q
Describe characteristics of the venules
A
- smallest of the veins
- endothelial, smooth muscle, and fibrous tissue
29
Q
Describe characteristics of the veins
A
- larger diameter and thickness compared to venule
- more smooth muscle and fibrous tissue
- some elastic tissue
30
Q
What components aid venous return?
A
- skeletal muscle pump: contraction of muscle compresses veins and pushes blood back towards the heart
- respiratory pump: inhale- diaphragm moves down, increases pressure in abdomen, compresses abdominal vessels, blood forced back to heart
31
Q
How is blood volume distributed throughout the body?
A
- systemic veins and venules contain 60% at rest
- blood can be diverted from here in times of need
- 15% of blood volume is in arteries and arterioles
