Lecture 11 Flashcards
What are the arteries located at the base of the heart (top)?
Right and left common carotid artery, right and left subclavian artery and brachiocephalic artery
What does the brachiocephalic artery split into?
The right subclavian artery - takes blood to the arms
Where does the carotid artery take blood to?
Takes blood to the head
What are the two main coronary arteries?
Right coronary and left coronary artery
What do the coronary arteries supply?
Supply the heart with oxygenated blood
Where do coronary arteries come off at the heart?
They come off at distinct positions on the aorta
What is coronary artery disease also called?
Ischaemic heart disease
What is the most common cause of cardiovascular disease?
Coronary artery disease
What is a myocardial infarction?
Heart attack
What is atherosclerosis?
Causes a reduction of blood flow, get a blockage, arteries become stiffer and plaque forms in narrowing the arteries. Some point the plaque will rupture and there will be complete blockage.
What happens when there is complete blockage in the arteries?
Cardiomyocytes die as no oxygen its getting to the muscle and a scar is formed.
What is the right coronary artery related to?
Related to the brachiocephalic artery
What are the carotid arteries susceptible to?
Arteriosclerosis
What is a common cause of arteriosclerosis in the carotid arteries?
Cerebral stroke, as there is not enough blood flow to the head if there is blockage in the carotid arteries
What are baroreceptors?
Are mechanism-receptors located in the carotid sinus and in the aortic arch
What do baroreceptors do?
Responds to a change in blood pressure, changes the tension of the arterial wall
Is the baroreceptor reflex fast to slow?
It is a fast response to changes in blood pressure
What does an increase in blood pressure cause?
Causes the walls of the aortic arch and carotid sinuses to stretch which increases the frequency of action potentials
What does the action potentials connect to?
The vasomotor and cardiac control centres in the medulla which then signals to the heart and vascular smooth muscle to decrease cardiac output and peripheral resistance
What is the baroreceptor pathway for low blood pressure?
Low blood pressure - baroreceptor firing rate decreases and increases heart rate to maintain homeostasis
Where are the subclavian arteries found?
Under the clavicles, take blood to the arms
What arteries come of the subclavian arteries?
Vertebral arteries
What is an anomalous right subclavian artery
Starts from the aortic arch more distally and transverses the midline behind the trachea and oesophagus
What is symptoms are from anomalous right subclavian artery?
Sometimes can be asymptomatic, but it can cause dysphagia lusoria (difficulty swallowing), due to the artery pressing on the oesophagus
What do the pulmonary arteries do?
Deliver deoxygenated blood from the right ventricles to the lungs
What are some problems that can affect the pulmonary arteries?
Stenosis - which restricts blood to the lungs
What is pulmonary stenosis?
A narrowing that occurs in the pulmonary artery. The narrowing could occur in the left or right pulmonary artery branches
What are the causes from pulmonary artery stenosis?
It is a congenial cardiovascular defect (can be part of the Tetralogy of Fallot), and increases blood pressure in the right side of the heart
What is the aorta?
Largest blood vessel in the body
What does the aorta do?
Takes oxygenated blood from the left ventricle to be distributed around the body. The aortic arteries arise from the aortic arch
What is not continuous with the aortic arch? In the condition ‘interruption of the aortic arch’
The descending aorta - it is interrupted
Describe the interruption of the aortic arch
Very rare 3 per 1 million births, serious condition, oxygenated blood will be able to leave the heart and go to the head and right arm but not the rest of the body.
What are the symptoms of the interruption of the aortic arch?
Closure of the arterial duct which results in an haemodynamic collapse and death within hours
Why is the interruption of the aortic so dangerous after birth?
Because as soon as the foetal shunt turns off after birth - no oxygenated blood will reach the rest of the body
What is the interruption of the aortic heart related to?
The 22q11 deletion syndrome
What are the three types of interruptions?
Type A B and C, most common is B
What is coarctation?
Defined as narrowing of a section of the aorta that will restrict the flow of blood from the heart
What are the symptoms for the coarctation?
Heart murmur, hypertension beyond infancy and congestive heart failure
What is the descending aorta?
Is the part of the aorta that runs down through the chest and the abdomen
Where does the descending aorta start?
Starts after the aortic arch and ends by splitting into the common iliac arteries that go to the legs
What is an aortic aneurysm?
It is an abnormal bulge that occurs in the wall of the aorta and may be tube-shaped (fusiform) or round (saccular)
What does an aortic aneurysm increase?
Increases the risk of developing an aortic dissection
What is an aortic dissection?
Is a serious condition in which the inner layer of the aorta (the intima) tears.
What happens when the intima tears?
Blood surges through the tear, causing the inner and middle laters of the aorta to separate (dissect)
What are the symptoms of the aortic dissection?
Depend on location and length of dissection, most cases result in death
What are the aortic arch arteries derived from?
Pharyngeal arch arteries
What are the pharyngeal arches?
Bulges that you find on the lateral surface of the developing embryo
What will the top of the embryo form?
The jaw
What will the bottom of the embryo cause?
Contributes to the formation of the thymus glands and nerves that innervates the facial part of the body
what is derived from each arch?
A cartilage, a muscle, a nerve and an artery
What are the pharyngeal arch arteries initially?
Symmetrical and paired
What do the pharyngeal arteries remodel to form?
Asymmetrical aortic arch arteries
What is the foetal duct?
Arterial ducts that takes blood away from the aorta
What do the aortic arch arteries stretch up until?
Stretches until it meets the little vessel to make the subclavian artery
What is the pharyngeal arch artery development like in humans?
Relatively rapid process occurring at a time of a rapid embryonic growth
What is the transcription factor for digeorge syndrome?
TBX1
What are the types of inherited arch artery malformations?
Interrupted aortic arch, aberrant right subclavian artery, patent ductus arteriosus, coarctation
What is the 22q11 deletion syndrome also known as?
Digeorge syndrome
What is the most common micro-deletion syndrome in humans?
The 22q11 (DiGEORGE) syndrome
What do patients with DiGeorge syndrome suffer with?
Cardiovascular, thymus and parathyroid abnormalities
What are the symptoms of DiGeorge syndrome?
Cleft plate, hypocalcaemia, immunodeficiency, renal abnormalities and increased risk of psychiatric disorders
Describe 22q11DS?
Interstitial deletion of chromosome 22, usually 3Mb but may be 1.5Mb. The transcription factor TBX1 is often found in the middle of the chromosomes on the small arm around 35 proteins genes
What does 30-40% of the patients who have 22q11DS have?
Common arterial trunk
What can be used to enable the study of genetics behind congenital cardiovascular malformations?
Transgenic mouse models
