Intro to CV system Flashcards
What is the circulatory system?
The circulatory system transports fluid throughout the body.
It consists of :
- Cardiovascular system
- Lymphatic system
What are the different types of blood vessels?
Arteries : Thick wall vessel that distribute blood and nutrients to tissues
Arterioles : final distributing vessels that deliver oxygen rich blood to the capillaries
Capillaries : (form capillary beds) site of exchange for oxygen, nutrients, waste products and other substances with the extracellular fluid.
Venules : where blood from the capillaries passes to ; drain into small veins that open into larger veins.
Veins : large vessels that transport back blood from capillaries to the heart.
Describe the aorta and its role.
The aorta is the main arterial trunk beginning from the left ventricule. It supplies oxygen rich blood to all parts of the body.
It has 3 parts.
- Ascending aorta (arise from left ventricule ; feeds coronary circulation i.e. myocardium by right & left coronary arteries).
- Arch of aorta (continuation of ascending aorta which feeds upper limbs, head, neck and face regions)
- Descending aorta (continuation of arch of aorta and feeds the thorax, abdomen, pelvis and lower limbs)
What are the respective roles of arteries and veins?
Arteries and its branches distribute blood to the body.
Veins and their tributaries bring blood from the body to the heart.
Briefly describe the lymphatic system and its role.
The lymphatic system is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphatic or lymphoid organs, and lymphoid tissues. The vessels carry a clear fluid called lymph back towards the heart, for re-circulation.
Unlike the circulatory system that is a closed system, the lymphatic system is open. The human circulatory system processes an average of 20 litres of blood per day through capillary filtration, which removes plasma from the blood. Roughly 17 litres of the filtered blood is reabsorbed directly into the blood vessels, while the remaining three litres are left in the interstitial fluid. One of the main functions of the lymphatic system is to provide an accessory return route to the blood for the surplus.
Fluid from circulating blood leaks into the tissues of the body by capillary action, carrying nutrients to the cells. The fluid bathes the tissues as interstitial fluid, collecting waste products, bacteria, and damaged cells, and then drains as lymph into the lymphatic capillaries and lymphatic vessels. These vessels carry the lymph throughout the body, passing through numerous lymph nodes which filter out unwanted materials such as bacteria and damaged cells. Lymph then passes into much larger lymph vessels known as lymph ducts. The right lymphatic duct drains the right side of the region and the much larger left lymphatic duct, known as the thoracic duct, drains the left side of the body. The ducts empty into the subclavian veins to return to the blood circulation.
The heart consists of 2 muscular pumps, adjacently located, dividing the circulation into two components. What are these 2 components ? Describe both.
- Pulmonary circulation (10%): Begins from the right ventricle to the lungs and back to the left atrium. The right ventricle pumps the blood to the right and left lungs through the pulmonary trunk and then through the right and left pulmonary arteries. Oxygenated blood then returns to the left atrium via the 4 pulmonary veins (2 from each right and left lung)
- Systemic circulation (85%): Begins from the left ventricle and supplies oxygen-rich blood to all the body systems via the aorta which delivers blood to all the systemic arteries, arterioles and finally into the capillaries (gaseous and nutrient exchanges occurs) and finally returns deoxygenated blood which is drained by venules and systemic veins into the superior and inferior venae cava which open to the right atrium of the heart.
Explained this image.
Define the following type of circulation.
This image represents portal circulation.
Normal blood flow goes from the arteries to capillary beds, then to veins and back to the heart.
The blood that passes through a portal system, passes 2 sets of capillaries.
Therefore, it goes : capillary – vein – capillary – vein.
Eg. Hepatic portal system, hypophysial portal system (pituitary) and renal portal system (in kidney nephrons)
Explain how the right and left common carotid arteries divide.
Each divide into external carotid artery for t_he face & neck_ and internal carotid artery for the brain. This division occurs near the angular mandible.
Explain how the subclavian arteries divide to supply the brain.
The subclavian arteries divide into right and left vertebral arteries to supply the brain.
What is the main artery of the upper limb?
The subclavian is the main artery of the upper limb.
At the outer border of the 1st rib, the subclavian artery becomes :
The axillary artery.
This artery supplies the shoulder region.
What is the main blood supply of the upper arm ?
Brachial artery.
It is a continuation of the axillary artery.
At the cubital fossa, it divides into radial (lateral)* and *ulnar (medial) arteries.
Radial and ulnar arteries supply the forearm.
The hand is irrigated by ?
The palmar arches.
(From radial and ulnar arteries)
Describe the abdominal aorta.
The descending thoracic aorta becomes the abdominal aorta when it crosses the diaphragm.
The abdominal aorta terminates at L4 and then divides into 2 common iliac arteries.
It gives off 3 unpaired and 5 paired branches along the way.
Name the unpaired arteries arising from the abdominal aorta.
- Celiac trunk (supply of foregut & spleen - level T12)
- Superior mesenteric (supply of midgut)
- Inferior mesenteric (supply of hindgut)
UNPAIRED ARTERIES SUPPLY THE GASTRO-INTESTINAL TRACT.
Name the different paired arteries that arise from the abdominal aorta (5).
- Inferior phrenic arteries
- Suprarenal arteries
- Renal arteries
- Gonadal arteries
- Lumbar arteries
What are the terminal branches of the abdominal aorta ?
Common iliac arteries.
The common iliac arteries divide into internal & external iliac arteries.
What does the internal iliac artery supplies ?
- Pelvic muscles
- Visceral structures
The external iliac artery is a direct continuation of the common iliac artery. What does the external iliac supply?
The lower limb.
At the mid-ingunial point, the external iliac becomes the femoral artery.
The deep femoral artery (profunda femoris) runs as a single trunk from the inguinal ligament to the lower third of the thigh. At the back of the knee it becomes :
The popliteal artery.
What does the popliteal artery supply ? What does it split into?
It supplies the knee and the structures around the popliteal fossa.
At the lower border of the popliteus muscle, the popliteal artery divides into :
Anterior tibial & posterior tibial.
What is the major blood supply of the leg?
Anterior and posterior tibial arteries.
The anterior tibial continues to the dorsum of the foot as dorsalis pedis artery.
The posterior tibial runs to the sole of the foot as lateral and medial plantar arches.
Overview of the systemic arterial system.
Name and briefly describe the 3 layers of the blood vessels (Tunics/Coats)
- Tunica intima - inner most layer consisting of a single layer of flattened epithelial cells (endothelium), supported by delicate connective tissue. (Capillaries consists of this tunic)
- Tunica media - middle layer consisting primarily of smooth muscle.
- Tunica adventitia - outer connective tissue or sheath.
What are end arteries ? Give examples.
End arteries DO NOT form anastomoses.
They are only one route arteries.
E.g. Renal and splenic arteries.
The right & left brachiocephalic veins are formed on each side by the union of ____ and ______.
Jugular veins
&
Subclavian veins
The inferior vena cava returns blood from all structures below the _______ to the right atrium.
Diaphragm.
The inferior vena cava ascends through the posterior abdominal region anterior the the vertebral colon immediately to the right of the ________ .
Abdominal aorta.
The superior vena cava begins posterior to the right __________, where the rights and left brachiocephalic veins join, and terminates at the lower edge of the right______, where it joins the right atrium.
1 costal cartilage
3rd costal cartilage
Briefly describe the difference between continuous, fenestrated and discontinuous capillaries.
Continuous : complete basal lamina, continuous endothelial lining.
Fenestrated : complete basal lamina, fenestrated endothelial lining.
Discontinuous : incomplete basal lamina, fenestrated endothelial lining.
Briefly describe lymphatic circulation.
Interstitial fluid — lymph capillaries — afferent lymphatic vessels — lymph nodes – efferent lymphatic vessels – lymphatic trunks – lymphatic duct — venous system.
