Cardiovascular system Flashcards
What are the three primary structural components of the cardiovascular system?
- Blood vessels
- Heart
- Blood
Name the three types of blood vessels
Arteries
Capillaries
Veins
What do arteries do?
carry blood AWAY from the heart (mostly carry oxygenated blood)
What do capillaries do?
supply blood cells with nutrients and oxygen and take waste products away
What do veins do?
Return blood to the heart (mostly carry deoxygenated blood)
What separates the two sides of the heart?
the septum - a muscular wall
What is the mediastinum?
The space located between the sternum, the vertebral column, the lungs and the diaphragm
What is the pericardium?
Triple-layered sac that encloses the heart
What is the fibrous pericardium
Outer, strong layer of dense connective tissue. Attached to diaphragm inferiorly and vessels of heart superiorly
What are the three components of the serous pericardium?
2a. Parietal layer - outer
2b. Visceral layer (epicardium) - directly covers the heart
Pericardial cavity - between the 2 layers and contains fluid film to reduce friction
Name the 3 layers of the heart
Epicardium
Myocardium
Endocardium
What is the epicardium?
Consists of visceral serous pericardium (“upon”)
What is the myocardium?
Cardiac muscle tissue, contractile layer
- Cardiac cells are interconnected at junctions called intercalated discs.
- spontaneously contracts - without neural input
- innervated by autonomic nervous system
What is the endocardium
Deep to myocardium, sheet of simple squamous epithelium on a thin layer connective tissue (lines chambers and valves)
How are the atria separated?
Interatrial septa
How are the ventricles separated?
Interventricular septa
What three functions does the fibrous skeleton have?
- Anchors heart valves by forming supportive rings (prevents over–opening)
- Provides a rigid framework for the attachment of cardiac muscle tissue in atria and ventricles
- Electrical insulation between atria and ventricles; ensures that muscle impulses are timed properly
What are the four valves in the heart?
- Pulmonary semilunar valve
- Right atrioventricular valve (tricuspid)
- Aortic semilunar valve
- Left atrioventricular valve (bicuspid)
What prevents the valves from being pushed back to the atria?
Papillary muscles and chordae tendineae
When are the papillary muscles relaxed and chordae tendineae slack?
bicuspid and tricuspid valves are open
When are the papillary muscles contracted and chordae tendineae taut?
bicuspid and tricuspid valves are closed
List four important features of the right atrium
- receives deoxygenated blood from systemic circulation via 3 blood vessels)
- Conveys blood into the right ventricle through the tricuspid valve (3 cusps)
- Contains the SA and AV nodes (parts of the heart conduction system)
- Important internal features: fossa ovalis
What three blood vessels go to the right atrium?
- Coronary sinus
- Superior vena cava
- Inferior vena cava
List to important features of the right ventricle
- Receives deoxygenated blood from the right atrium and pumps it into the pulmonary circuit
- important internal features: trabeculae carnae line the walls of both ventricles
How does deoxygenated blood reach the right ventricle?
Through the pulmonary trunk via the pulmonary semilunar valve
List three important features of the left atrium
- receives oxygenated blood from pulmonary circulation via 4 pulmonary veins (2 left and 2 right)
- separated from the left ventricle by bicuspid (mitral) valve (2 cusps)
- Important internal features: auricle contains pectinate muscles (musculi pectinati)
List two important features of the left ventricle
- forms the apex of the heart
- pumps blood into the systemic circuit through the aortic semilunar valve into the aorta
Approximately how thick are the ventricular walls?
Right: 3mm
Left: 13mm
Describe the flow of blood through the pulmonary circuit
Pumps blood from the right side of the heart through pulmonary vessels, to the lungs, and back to the left side of the heart.
Describe the flow of blood through the systemic circuit
Pumps blood from the left side of the heart, through systemic vessels in peripheral tissues, and back to the right side of the heart.
What do the sulci do and what are the 3 major ones
Sulci separate the four chambers, and major coronary blood vessels occupy these sulci
- Atrioventricular (coronary) sulcus - separates atria from ventricles
- Aterior interventricular sulcus - separates ventricles
- Posterior interventricular sulcus - separates ventricles
Where do the coronary arteries originated from and what do they supply?
- coronary arteries originate from the base of the aorta (superior to the aortic valve)
- Coronary arteries supply oxygen and nutrients to the heart muscle and coronary veins drain the blood
What does the coronary sinus do?
It is the biggest cardiac vein which ultimately collects the blood from all cardiac veins and drains the blood into the right atrium
Where are the coronary sinus and great and small cardiac veins located?
In the coronary (atrioventricular) groove
Where is the middle cardiac vein located?
in the posterior interventricular groove
What is the role of the three cardiac veins
Great cardiac vein: primarily drains the left heart (left atrium and ventricle)
Small cardiac vein: drains the right heart (right atrium and ventricle)
Middle cardiac vein: drains the interventricular septum
Describe the five steps of the cardiac conduction system
- SINOATRIAL (SA) node (the pacemaker): initiation of heartbeat
- SA node signal travels to the ATRIOVENTRICULAR (AV) node - AV node slows down the activation allowing time for atria to contract
- From the AV node the signal travels along the BUNDLE BRANCHES
- From the AV bundle the signal travels to the ventricles via the PURKINJE FIBRES
- Purkinje fibres spread signal to allow for rapid contraction of ventricles
How does innervation of the vagus nerve effect the heart?
PARASYMPATHETIC
- decreases heart rate
- No effect on contraction
Innervates the SA, AV nodes and coronary arteries.
How does innervation of the sympathetic trunk effect the heart?
SYMPATHETIC
- increases heart rate
- increases strength of cardiac contraction
Innervate the SA, AV nodes, coronary arteries and cardiac musculature
Describe tunica intima
inner simple squamous epithelium forming smooth surface of lumen
Describe tunica media
middle, circularly arranged smooth muscle cells. Contraction/relaxation changes vessel diameter (thickest layer)
Describe tunica externa
Outer protective connective tissue layer, strengthens and anchors
What parts of the artery does blood consecutively travel through
From elastic arteries to muscular arteries to arterioles
Describe an elastic artery
CONDUCTING
- largest, low resistance, near the heart
- high in elastin (tunica media)
- allows large pressure surges from the heart
E.g. pulmonary trunk, aorta, common carotid arteries
Describe a muscular artery
DISTRIBUTING
- distal, supply groups of organs
- tunica media is thicker relative to lumen
- smooth muscle sandwiched b/w 2 elastin layers
- muscular layer regulates blood flow to organ
E.g. external carotid arteries, arteries of the limbs
Describe the arteriole
- smallest arteries, lead to capillary beds
- thin tunica media of smooth muscle cells
- contraction/ relaxation regulated via local signals OR sympathetic nervous system
Describe the structure of the capillary
- smallest blood vessels (diameter with single blood cells)
- Single layer of endothelial cells
What are the three types of capillaries
Continuous - most common, least permeable
Fenestrated - have pores for high exchange rates
Sinusoid - very leaky for high exchange of large molecules
How do veins get blood back to the heart?
- infolds of the tunica intima create valves to allow for unidirectional flow of blood
- valves are opened by blood flow to heart and closed by backflow
- most abundant in limbs
What three arteries originate from the aortic arch?
- brachiocephalic trunk
- left common carotid artery
- left subclavian artery
What are the two divisions of the brachiocephalic trunk?
- right common carotid artery
- right subclavian artery
Where do the branches of the aortic arch supply with blood
the head, neck, upper limbs and superior thoracic wall
What are the 4 pairs of arteries that serve the head and neck
- common carotid artery
- vertebral artery
- thyrocervical trunk
- costocervical trunk
What blood vessels supply the brain?
Branches of the left and right internal carotids and the left and right vertebral arteries.
What is the Circle of Willis?
CEREBRAL ARTERIAL CIRCLE
an arterial anastomosis that provides alternate routes for blood to reach brain areas if occlusion
What are the blood vessels in the circle of willis from posterior to anterior?
Left and right vertebral a. -> basilar a. -> posterior cerebral a. -> posterior communicating a. -> middle cerebral a. -> anterior cerebral a. -> anterior communicating a.
Where do the branches of the thoracic aorta go?
- numerous small branches to thoracic viscera and posterolateral wall
- the anterior and upper abdominal wall are supplied by branches of the subclavian arteries: internal thoracic arteries
ALSO: - pericardium
- lungs and bronchi
- esophagus
What three unparied arteries supply the gastrointestinal tract and spleen
- Celiac artery
- superior mesentric a.
- Inferior mesentric artery
What are the 3 paired arteries off the abdominal aorta
- (middle) suprerenal arteries
- Renal arteries
- Gonadal arteries
The abdominal aorta ends by dividing into 2 common illiac arteries, which divide into what?
- internal iliac arteries (pelvic organs, genitals)
- External illiac arteries (lower limbs)
What is the flow of blood through the upper limbs?
Upper limbs arteries arise from the subcalvian a. -> (under clavicle) axillary a. -> brachial a. -> radial and ulnar arteries.
What is the flow of blood through the arteries in the lower limb?
Lower limb arteries arise from the external iliac artery -> femoral artery -> popliteal artery -> anterior and posterior tibial arteries
What artery supplies blood to the hip joint and thigh muscles?
Femoral artery
What artery supplies blood to the knee?
The popliteal artery
Where does the anterior tibial artery supply with blood?
Branches to the DORSALIS PEDIS ARTERY (form plantar arch) and DIGITAL ARTERIES extend from plantar arch and supply the toes
Where does the posterior tibial artery supply with blood?
Branches to the FIBULAR ARTEERY (lateral compartment leg muscles) and MEDIAL AND LATERAL PLANTAR ARTERIES
What are the three veins that systemic blood returns to the heart through
- superior vena cava
- inferior vena cava
- coronary sinus
What are the three main veins of the head and neck?
- internal jugular
- external jugular
- vertebral veins
Where does the internal jugular receive blood from?
The dural venous sinuses (and most of the brain)
Where does the external jugular receive blood from?
From posterior and lateral scalp and some of the face
Where does the vertebral veins receive blood from?
From the cervical vertebrae and spinal cord, superior neck muscles
What veins drain into the radial and ulnar veins?
The digital veins; superficial and deep palmar venous arches
What do the radial and ulnar veins merge to form?
A pair of brachial veins
What two veins merge to form the axillary vein?
The brachial veins and the basilic vein
How is the axillary vein renamed?
The subclavian vein (first ribs)
Where is the basilic vein?
SUPERFICIAL - runs adjacent to the medial surface of the upper limb and eventually helps form the axillary vein
Where is the cephalic vein
SUPERFICIAL - runs alongside the lateral aspect of the upper limb and drains into the axillary vein
Where is the median cubital vein?
interconnects the basilic and cephalic veins
What vein drains the abdominal wall, the gonads, the liver, the kidneys and the suprarenals glands and the diaphragm?
Inferior vena cava
What vein drains the visceral organs within the abdominal cavity?
The hepatic portal vein
What are the 6 major veins from the abdominal portion which the inferior vena cava collects? (superior to posterior)
- phrenic veins
- hepatic veins
- suprarenal veins
- renal veins
- gonadal veins
- lumbar veins
What are two blood supplies the liver recieves?
- the “hepatic portal vein”
- The “hepatic artery proper”
What kind of blood goes through the hepatic portal vein
oxygen poor, but nutrient rich blood, drains only unpaired organs
What kind of blood does the hepatic artery proper contain?
Oxygen rich blood
What does the inferior mesentric vein do?
drains the distal part of the large intestine; receives blood from the superior rectal vein, sigmoid veins and left colic vein
What does the splenic vein do?
Drains the spleen: received blood from pancreatic veins, short gastric veins, and the right gastroepoploic vein
What does the superior mesentric vein do?
Drains the small intestine and part of the large intestine; receives blood from the intestinal veins, pancreaticoduodenal veins, ileicolic vein, and right and middle colic veins
List the deep veins of the lower limb and where they drain to
- medial and lateral plantar veins drain into posterior tibial veins
- fibular veins drain into the posterior tibial veins
- tibial veins merge to from the popliteal vein which becomes the femoral vein and then the external iliac vein (superior to the inguinal ligament)
- external and internal iliac veins unite into the common iliac vein
- The common iliac veins merge to form the inferior vena cava
List the superficial veins of the lower limb and where they drain to
- dorsal venous arch drains into the great saphenous veins and small saphenous vein
- Great saphenous vein drains into the femoral vein
- small sephanous drains into popliteal vein
What are the three functions of the lymphatic system?
- return lymph to the systemic venous system, to maintain blood volume and fluid levels and return leaked proteins back to the blood
- carry absorbed fat from the intestine to the blood
- lymph nodes act as filters to check for foreign or pathological materials, thus fighting infection by foreign bodies via lymphocytes
What are the 5 lymphoid organs and what do they do
- red bone marrow - produces lymphocytes
- Thymus - maturation of T-lymphocytes
- Spleen - monitors blood
- Lymph nodes - monitors lymph, destroy pathogens
- Tonsils - destroy pathogens
What are the features of lymphatic capillaries?
- vessels that receive lymph
- components of blood plasma filter through blood capillaries = interstitial fluid
- lymphatic capillaries are highly permeable (more permeable than blood capillaries)
- Excess interstitial fluid flows into lymphatic capillaries
What is the one way flow of lymph?
lymphatic capillaries -> lymphatic vessels -> lymphatic trunks -> lymph ducts
What are the primary lymphoid organs?
red bone marrow
thymus
What are the secondary lymphoid organs?
lymph nodes
spleen
tonsils
What are the five ways in which the lymphatic and cardiovascular systems work together?
- continual recycling of fluid from bood to tissue fluid to lymph and back to the blood
- blood capillaries lose fluid to tissue spaces, picked up by lymphatic system, returned to bloodstream
- lymph flows from lymphatic capillaries through collective vessels, lymphatic trucks, collective ducts and is filtered through multiple lymph nodes before re entering the bloodstream at the subclavian veins
- the lymphatic system flows at lower pressure and speed then the venous blood
- the valves of the lymphatic vessels, like those of the veins, prevent the fluid from flowing back
