The Cardio Vascular System Flashcards
Vasodilation
widening of blood vessels as a result of the relaxation of the blood vessel’s muscular walls.
Vasodilation is a mechanism to enhance blood flow to areas of the body that are lacking oxygen and/or nutrients.
vasoconstriction
is the narrowing (constriction) of blood vessels by small muscles in their walls. When blood vessels constrict, blood flow is slowed or blocked.
Vasoconstriction may be slight or severe. It may result from disease, drugs, or psychological conditions
How Blood Clots -Haemostasis
Vasoconstriction
Platelets become sticky and adhere to the damaged wall
Platelet Plug formation
Platelets clump together attracting more platelets forming a temporary seal
Coagulation ( Blood Clotting)
Clotting factors activate each other in a specific order
Fibrinolysis
This is the process of healing the damaged blood vessel
Tunica Adventitia
outer layer, fibrous tissue, supports and protects the blood vessel.
Tunica Media
middle layer of smooth muscle and elastic tissue.
Tunica Intima – or endothelium.
Smooth lining, one cell in thickness.
What does anastomosis mean?
Joining of 2 tubes (ulnar and radius arties do this)
What vertebrae does the thoracic aorta become the abdominal aorta
T12
Arteries for upper limbs?
Ascending aorta -> Arch of aorta -> brachiocephalic trunk -> Subclavian artery -> axillary artery -> brachia artery -> Radial artery/ulna artery -> palmer arch
Arteries for abdominal
Ascending aorta -> Arch of aorta -> Descending thoracic aorta -> abdominal aorta -> Coeliac axis/trunk and Superior Mesenteric Artery and Inferior Mesenteric Artery
What vertebrae is the coeliac trunk at?
T12
What vertebrae is the Superior Mesenteric Artery at?
L1 and L2
What vertebrae is the Inferior Mesenteric Artery at?
L3
Organs and their arteries
Diaphragm – phrenic artery Stomach – Gastric artery Liver - Hepatic artery Pancreas – Pancreatic artery Spleen - Splenic artery Suprarenal / adrenal glands Kidneys - Renal arteries Gonads - Uterine or testicular arteries Lumbar (usually 4 pairs)
Arteries for the lower limb?
At the end of the aorta it divides into 2 common iliac arteries (internal iliac artery for organs in the pelvis) and external iliac artery -> femoral artery -> popliteal artery/fossa -> Anterior/posterior tibial artery and peroneal artery -> plantar arch
What vertebra is the common iliac artery at? wherein the pelvis?
L4, in front of the SIJs
Arteries for head
Ascending aorta -> Arch of aorta -> brachiocephalic trunk -> common carotid artery (internal skull/external face) // Subclavian artery -> Vertebral arteries (to the brain)
Interior of Heart
Divided into Right and Left sides by a septum
Each side is divided by an atrioventricular valve into an upper atrium and a lower ventricle
What side is the tricuspid valve?
Right
What side is the Bicuspid valve or Mitral Valve?
Left
What holds the valves
Flaps of the valves are held by chordae tendineae, which fasten to the papillary muscles.
The papillary muscles are tiny extensions from the inner wall of the heart.
Pericardium has 2 sacs 2 sacs
Fibrous pericardium
Serous pericardium
What does each do
Fibrous pericardium
Continuous with the tunica adventitia.
Attached to diaphragm
Protects and prevents over distention of the heart
Serous pericardium
Folded double layer around the heart – like the pleura in the lungs.
Inner layer is firmly attached to the myocardium.
Outer layer is attached to the fibrous pericardium.
20mls of pericardial fluid in between – lubricates the space, so the heart doesn’t rub against the fibrous sac.
Myocardium facts?
Striated muscle, not under voluntary control
Cells are arranged in a continuous sheet, allowing the whole heart to contract in a co-ordinated and efficient manner
Network of fibres run between that transmits the hearts electric signals
Thickest at the apex, thins towards the base
Thickest in the left ventricle as this has to push the blood around the whole body.
Endocardium facts?
Lines the chambers and valves
Flattened epithelial cells that are continuous with the lining of the blood vessels
Blood flow in the heart
2 largest veins – superior vena cava (SVC) and inferior vena cava (IVC) flow into the Right Atrium (RA)
This increases pressure in the RA – opening the tricuspid valve
Blood enters the Right Ventricle (RV)
The pressure in the RV increases, the tricuspid valve shuts, the ventricle contacts and pushes blood out into the Pulmonary Trunk, which divides into the Right and Left Pulmonary Arteries
The exit is guarded by the pulmonary valve
Pulmonary Circulation
Blood goes to the lungs, where gaseous exchange happens.
CO2 is removed and O2 in taken in.
2 Pulmonary Veins then carry blood back to the Left Atrium (LA)
This increases pressure in the LA – opening the Bicuspid valve
Blood enters the Left Ventricle (LV)
Pressure in the LV increases, the Bicuspid valve shuts
The Blood Supply to the Heart
Heart is supplied by Right and Left Coronary Arteries -which arises immediately off the aorta as it leaves the left ventricle.
5% of the blood pumped from the heart, goes to these arteries.
Drained by coronary sinus that empties into the right atrium.
The Conducting System
The heart generates its own electrical impulses.
Its is supplied with both sympathetic and parasympathetic nerve fibres which can increase and decease the heart rate respectively
It also responds to certain hormones, including adrenaline and thyroxine.
Sinoatrial node
Sinoatrial node (SA node) is a small collection of specialised cells
Found in wall of the RA near the opening of SVC
It generates an electrical impulse faster that any other part and is known as the pacemaker of the heart
60 – 90 times per minute
The impulse from the SA arrives at the atrioventricular node at 0.1 secs later
Atrioventricular node
The atrioventricular node (AV node) is a small mass of neuromuscular tissue in the wall of the atrial septum near the atrioventricular valves
It transmits the electrical signals from the atria to the ventricles.
40 – 60 beats per minute
This takes 0.1 seconds – allowing the atria to finishing contacting before the ventricles do.
Atrioventricular Bundle
Atrioventricular Bundle (AV Bundle or Bundle of His) is a mass of specialised fibres that come from the AV node. They pass through to the ventricles and divided into right and left branches Within the ventricular myocardium they divided into the Purkinje Fibres
The AV bundle, bundle branches and Purkinje fibres transmit the electrical impulses from the AV node to the apex of the heart, where the wave of ventricular contraction begins, sweeping upwards and outwards pumping blood into the pulmonary trunk and the aorta.
What is ischemic heart disease?
It’s the term given to heart problems caused by narrowed heart arteries. When arteries are narrowed, less blood and oxygen reaches the heart muscle. This is also called coronary artery disease and coronary heart disease.
What is angina?
Angina is a type of chest pain caused by reduced blood flow to the heart. Angina is a symptom of coronary artery disease. Angina, also called angina pectoris, is often described as squeezing, pressure, heaviness, tightness or pain in your chest.
Myocardial infarction (MI)?
Myocardial infarction (MI) refers to tissue death (infarction) of the heart muscle (myocardium) caused by ischaemia.
Congestive heart failure (CHF)
Heart failure is where the heart is unable to pump blood around the body properly and needs treatment to help it work.
Atheroma
Atheroma is the medical term for the buildup of materials that adhere to arteries. Among others, these include: fat. cholesterol.
Sclerosis
Sclerosis is the stiffening of a tissue or anatomical feature, usually caused by a replacement of the normal organ-specific tissue with connective tissue.
A thrombus
A thrombus is a blood clot that forms in a vessel and remains there. An embolism is a clot that travels from the site where it formed to another location in the body
Aneurysm
An aneurysm is a bulge in a blood vessel caused by a weakness in the blood vessel wall, usually where it branches. As blood passes through the weakened blood vessel, the blood pressure causes a small area to bulge outwards like a balloon.
Embolism
What is an embolism?
A blood clot that forms in a blood vessel in one area of the body, breaks off, and travels to another area of the body in the blood is called an embolus. An embolus can lodge itself in a blood vessel. This can block the blood supply to a particular organ.
DVT
Deep vein thrombosis (DVT) is a medical condition that occurs when a blood clot forms in a deep vein. These clots usually develop in the lower leg, thigh, or pelvis, but they can also occur in the arm.
Varicose vein
Varicose veins are caused by increased blood pressure in the veins. Varicose veins happen in the veins near the surface of the skin (superficial). The blood moves towards the heart by one-way valves in the veins. When the valves become weakened or damaged, blood can collect in the veins.
