*Anatomy -Circulatory System Flashcards
What are the great vessels?
Thos directly connected to the heart chambers
What structures are contained within a neurovascular bundle?
Nevre
Artery
Vein
What is a territory?
A body region/ organ supplied by an artery and its branches
Give an example of an artery that trifurcates?
the celiac trunk
What does the term “trunk” or “common” indicate about an artery?
That it will definitely divide again
what os the course of an artery?
The arteries journey from its origin to its termination
Why do arteries often run a tortuous course?
It helps to prevent over-stretching/ tearing
Why are arteries usually located deeper than veins?
Helps reduce the chance of a more serious haemorrhage
How can you limit blood loss from an artery?
By pressing on a pulse point proximal to the injury
What do the elastic fibres found in the walls of the largest, most proximal arteries do?
Permit expansion of the aorta to accommodate the blood forced into it during systolee
Help to maintain blood pressure during diastole via elastic recoil
Which arterial blood vessels contain smooth muscle?
Arterioles
Some arteries called “muscular arteries”
What happens when smooth muscle in walls of arterioles and muscular arteries contracts?
Vasoconstriction occurs which reduces blood flow to the organ/ tissue supplied
What is the opposite of vasoconstriction?
What causes this?
What does it do?
Vasodilation
Widens the lumen increasing the blood flow to the organ/ tissue supplied
Relaxation of smooth muscle
What does the arterioles and muscular arteries go into to to help reduce blood loss following an injury?
Spasm (smooth muscle contracts)
In terms of smooth muscle, what always exists in arteriolar smooth muscle?
What does this mean?
Called?
There is always a background low level of contraction of arteriolar smooth muscle
Arterioles are most often slightly narrowed compared to their maximum internal diameter
Sympathetic tone
What causes the sympathetic tone of arteriolar smooth muscle?
Tonic conduction of action potentials to arterioles by sympathetic nerves
What segments of the spinal cords have lateral horns?
T1 to L2 segments
How long is the sympathetic trunk?
Full length of the vertebral column
In the body wall what does the sympathetic fibres supply? (3)
Skin sweat glands
Skin arrestor muscles
ALL arterioles (sympathetic tone)
Via which nerves are the organs supplied with sympathetics?
Splanchnic nerves
What is the territory of the aorta?
The whole body
What are the 2 branches from the ascending aorta?
The right and left coronary arteries
What are the 3 branches from the arch of the aorta?
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
What does the brachiocephalic trunk bifurcate into?
the right common carotid and right subclavian arteries
What branches from the subclavian arteries which passes to the cranial cavity?
How does it travel to the cranial cavity?
The right vertebral artery
Passes through transverse foramina in cervical vertebrae then through foramen magnum
What does the common carotid arteries bifurcate into?
The external carotid arteries and the internal carotid arteries (one of each in each side e.g. right internal carotid artery)
Where does the external carotid arteries pass and to supply what?
Remains external to the cranial cavity to supply the face and scalp
Where does the internal carotid arteries pass and to supply what?
Becomes internal to the cranial cavity via the carotid canal to supply the brain
What is the circle of arteries called on the inferior aspect of the brain?
The circle of Willis
What do the right and left vertebral arteries joint to form (on the inferior aspect of the brain)?
Basilar artery
What does the basilar artery give off?
Right and left communicating arteries
What is the most proximal (usually dilated) part of the internal carotid artery called?
The carotid sinus
What level is the carotid sinus located?
At the level of the superior border of the thyroid cartilage
What innervates the carotid sinus and carotid body?
The glossopharyngeal nerve (CN IX)
What is the function of the glossopharyngeal nerve at the carotid sinus?
To detect stretching of the walls of the carotid sins (i.e. beat to beat changes in arterial blood pressure)
What does the carotid body monitor?
blood gas levels/ pH
What are present between the brain capillary endothelial cells?
Tight junctions
What surrounds the brain capillaries?
Astrocytes
What is the purpose of tight junctions between brain capillary endothelial cells and astrocytes surrounding the brain capillaries?
To prevent the diffusion of some substances from capillary into brain tissue e.g. antibiotics
What can diffuse through the blood brain barrier?
O2 and CO2 (and ethanol)
What is an anastomoses?
When arteries connect with each other without an intervening capillary network
How do anastomoses help if an artery occlusion occurs?
Provides an alternative route for blood to flow to supply the cells distal to an arterial occlusion
What is an alternative route of blood flow in any given anastomosis?
A collateral
What do collateral vessels around joints permit?
Flow to the limb peripheries no matter the position the joint is held in
What is an end artery?
The only arterial blood supply to a given area of the body (there are no collaterals)
What does treated occlusion of an end artery result in?
Infarction of its territory
What does infarction mean?
Irreversible cell death due to hypoxia caused by loss of arterial blood supply
What are the names of the arteries running through an upper limb?
Left subclavian artery becomes
Left axillary artery becomes
Left brachial arter bifurcates into
Left radial artery and let ulnar artery
What are the branches from the thoracic aroma’s anterior surface? (5)
Bronchial arteries (arterial supply for the lung tissue) Oesophageal arteries Mediastinal arteries Pericardial arteries Phrenic arteries (for the diaphragm)
What are the bilateral branches from the aorta?
Posterior intercostal arteries (supply the chest wall)
What does the abdominal aorta bifurcate to form?
The left and right common iliac arteries
What do the common iliac arteries bifurcate to form?
The external and internal iliac arteries
what does the external iliac arteries supply?
The lower limbs
What does the internal iliac arteries supply?
The pelvis and perineum
Where is the carotid pulse felt in terms of arteries?
At the bifurcation of the common carotid artery
Over what vessel is the femoral pulse felt?
At the continuation of the external iliac artery in the midpoint of the groin
Over what artery is the popliteal pulse felt?
The popliteal artery
Where is the posterior tibial pulse felt?
Over the posterior tibial artery posterior to the medial malleolus of the tibia
Where is the dorsalis pedis pulse felt?
Over the dorsalis pedis artery on the dorsum of the foot
Instead of branching, what do veins have?
Merging tributaries
How much of the circulating blood volume does veins contain?
About 60%
Do veins contain smooth muscle?
Why?
Yes (a thin layer)
walls can contract to reduce venous capacity and return blood to the arterial side of the circulation e.g. in haemorrhage
Are veins courses usually straight or torturous?
straight
What do veins appear like when they are not full of blood?
Collapsed flat
How is the venous blood pumped back towards the heart?
The contraction of skeletal muscles in the lower limbs (“skeletal muscle pumps”)
Chest cavity pressure changes associated with the movement of breathing
(venous pumps require venous valves in limb veins to ensure unidirectional flow back the heart against gravity)
Where are the superficial veins located?
What do these drain into?
Where are these located?
In the superficial fascia
Deep veins
Run deep to the deep fascia and in cavities often in NVB
What are the 2 main venous systems in the body?
The hepatic portal venous system
The systemic venous system
What doe lymphatic capillaries collect?
what is the fluid called once in these capillaries?
Tissue fluid
Lymph
What do lymphatic capillaries from tissues/ organs join together to form?
Lymphatics (lymphatic vessels)
What 2 main lymph vessels is lymph either drained into?
Thoracic duct (3/4 of body) Right lymphatic duct
Where does the thoracic duct drain lymph back into the venous system?
At the left venous angle
where does the right lymphatic duct drain lymph into?
The right venous angle
