The cardiac system Flashcards
Where is the heart located in most veterinary species?
In the chest cavity
What is the function of the cardiovascular system?
To continuously pump blood around the animals body and as such allow blood to fulfill its functions
Name the 4 main chambers of the heart
The left atrium, the left ventricle, the right atrium and the right ventricle.
What is the name of the heart muscle
The myocardium
Starting at the lungs describe the order in which the blood flows through the chambers of the heart
Lungs -> Left Atrium -> Left Ventricle -> Body and Brain -> Right Atrium -> Right Ventricle -> Lungs.
What is the area in the heart that controls heart rate?
The sinoatrial node
What is the name of the part of the cardiac conduction system that slows conduction of electrical signals to the ventricles to allow atrial contraction to be completed?
The atrioventricular node
In which direction, apex to base or base to apex do the ventricles contract? Why?
Apex to base. Contraction occurs in this direction because it is the direction in which the blood must be pushed to leave the ventricles and enter the aorta or the pulmonary artery.
What is the name for the period during the cardiac cycle when the myocardium is working?
Systole
What is the name for the period during the cardiac cycle when the myocardium is relaxing?
Diastole
What is the role of the cardiac muscle cell in the SA node?
To automatically generate the electrical impulses that trigger each heartbeat.
What microscopic structures allow cardiac muscle cells to transmit electrical impulses to neighboring cells?
Gap junctions
What anatomical structures create the heart sounds?
The heart valves
What 2 abnormalities in heart valves create heart murmurs?
Insufficiency or an inability to close properly and stenosis or an abnormal narrowing.
What features of heart murmurs are used when describing them?
Their intensity, their timing during the cardiac cycle and the location of their point of maximum intensity.
What is the definition of cardiac output (CO)?
The volume of blood ejected from the left ventricle in a set period of time usually 1 minute.
What determines cardiac output?
Stroke volume (SV) multiplied by heart rate (HR).
What is stroke volume?
The volume of blood ejected from the left ventricle during one contraction or systole
What factors determine stroke volume?
The volume of blood received from atrium into the ventricles or preload & the physical resistance by the artery the ventricle is ejecting blood into or afterload.
Describe the function of the heart valves
They prevent blood from flowing back where it has come from.
Describe the features of arteries.
Arteries are blood vessels that originate in the heart and deliver blood either to the lungs to be oxygenated or to tissues to deliver oxygen and nutrients. The blood they contain is under high pressure.
Describe the features of veins
Veins are blood vessels that originate in tissues and return blood to the heart. The blood they contain is under low pressure.
What are the roles of capillaries?
They are the location of the delivery of oxygen and nutrients to tissues and the removal of carbon dioxide and waste products from the tissues.
Which area of the heart is formed by the ventricles?
The apex
Starting at the vena cava describe blood flow through the heart and body.
Vena cava -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> left ventricle -> Aorta -> peripheral circulation -> vena cava.
What is the function of the cardiac valves?
They ensure that blood flow goes in one direction (unidirectional) by stopping it from flowing back where it came from.
What is the name of the heart valve located between the right atrium and right ventricle?
The tricuspid valve.
What is the name of the heart valve located between the left atrium and left ventricle?
The mitral valve.
What is the name of the valve that prevents blood from flowing back from the pulmonary artery into the right ventricle?
The pulmonic valve.
What is the name of the valve that prevents blood from flowing back from the aorta into the left ventricle?
The aortic valve.
What is the name of the blood vessels that supply blood to the heart muscle?
Coronary arteries.
True or False. The heart needs stimulation from the nervous system to beat.
No. The heart beats spontaneously but the rate at which it beats can be influenced from messages from the nervous system.
True or false. Oxygen in the fetus comes from the fetal lungs?
False. Oxygen in the fetus comes from the mothers’ lungs via the umbilicus.
Wat 2 structures allow most fetal blood to bypass the fetal lungs.
The foramen ovale allows blood in the right atrium to pass directly into the left atrium. The ductus arteriosus allows blood that enters the pulmonary trunk to pass straight into the aorta.
What creates a pulse in an animal (or human)?
It is the stretching and recoiling of the elastic fibres in the wall of arteries in response to the ejection of blood from the left ventricle during a heart beat.
What is the most common artery used to palpate a pulse in a dog or a cat?
The femoral arteries that are located on the medial aspect of the hind legs.
When measuring blood pressure what is the name of the higher of the 2 values?
The systolic blood pressure.
Name 3 methods of monitoring the heart
Auscultation of the thorax, peripheral artery palpation, arterial blood pressure evaluation,thoracic radiography, electrocardiography & echocardiography.
What does an electrocardiogram trace represent?
The electrical activity of the heart.
What activities in the heart does the QRS complex represent?
Ventricular depolarization which occurs during contraction.
What is echocardiography?
Ultrasound examination of the heart.
What does Doppler echocardiography look at?
Flow of blood through the heart.
What is the most common venipuncture site in the horse?
The jugular vein.
What are the most common venipuncture sites in the dog and cat?
Dog and Cat - Jugular vein & cephalic vein.
Dog - lateral saphenous vein.
Cat - Medial saphenous vein(?correct).
