Unit 1 - Anatomy and physiology for health and exercise - the cardiovascular system Flashcards
What are the four chambers of the heart called?
- 2 upper chambers: atria (atrium in singular)
- 2 lower, larger chambers: ventricles
What is the name of the predominant tissue of the heart?
The cardiac muscle or myocardium
What do atrioventricular vales do?
The Atrioventricular valves are Mitral and Tricuspid valves located between the atrium and ventricles. Their main functions is to “prevent the backflow of blood from the ventricles into the atrium during the ventricular contraction (systole).
What is the function of the coronary arteries?
Coronary arteries supply blood to the heart muscle. Like all other tissues in the body, the heart muscle needs oxygen-rich blood to function. Also, oxygen-depleted blood must be carried away. The coronary arteries wrap around the outside of the heart.
What factors can lead to damage these coronary arteries and dysfunction and therefor limit blood flow to sections of the heart?
Mineral, protein and fatty deposits can build up in the walls of the arteries.
These hard mineral deposits reduce the elasticity of the arteries so they cant stretch in response to blood flow and increased blood pressure can result.
Sudden heart attack can often be a result of one of these deposits bursting, releasing their contents and initiating a rapid colouring process to stop the blood from escaping the artery.
What can a forming blood clot stop?
it can stop blood flow which results in oxygen deprivation to a section fo the heart.
The body responds with a rapid increase in heart rate to try and dislodge the blockage and re-establish blood flow.
This very rapid beating, oxygen-deprived heart, is what is experienced during a heart attack.
What is blood pressure?
A measure of the force that the blood applies to the walls of the arteries as it flows through them.
How is blood pressure measured (what unit measure is used)?
Blood pressure is measured in millimetres of mercury (mmHg), using two numbers.
What is the optimal blood pressure, with respect to cardiovascular risk?
Below 120 mmHg for systolic and 80 mmHg for diastolic pressure.
120/80
What is hypertension?
It’s the clinical term used to describe a high blood pressure of 140/90 mmHg or higher
What is the short-term effect of exercise on blood pressure?
It increases blood pressure.
What is a central element to the heart’s conduction system, by which it directs the course of electrical activity (action potential) through the tissues of the heart?
Two small bundles of fibres located in the right atrium:
- the sinoatrial (SA) node
- the atrioventricular (AV) node
What is the sinoatrial node?
The SA node is a collection of elf excitable cells; they require no neural input and are the site where cardiac action potentials begin.
Here, action potential spread across both atria and thus, they will contract first.
By what is the flow of action potentials to the ventricles controlled?
Via the AV node which is located at the base of the right atrium.
Its function is to slow down the action potential and give the atrial time to contract.
From here the action potential travels down a specialised nerve bundle before branching off into two bundles in the central wall of the heart (the septum).
What is the central wall of the heart called?
The septum
Describe the cardiac cycle.
The cardiac cycle describes all the activities of the heart through one complete heartbeat—that is, through one contraction and relaxation of both the atria and ventricles.
A contraction event (of either the atria or ventricles) is referred to as systole, and
a relaxation event is referred to as diastole.
Give a brief summary of the cardiac cycle.
- Relaxation (diastole): of the atria allows blood to refill them form the pulmonary veins and vena cava.
- Atrial systole (contraction): stimulation form the SA node causes the atria to contract and push any remaining blood into the ventricles.
- Ventricular systole (contraction): the ventricles contract causing a rise in pressure. This closes off the AV valves and directs the blood to be ejected from the heart via the pulmonary artery and aorta.
- Relaxation (diastole): the atria relax followed by the ventricles until all four chambers are in diastole and the cardiac cycle begins over again.
Apart from the SA node dictating the basic rhythm of the heartbeat, how else is the heart cycle regulated?
Regulation of the cardiac cycle is also achieved via the autonomic nervous system. This is primarily directed by the medulla oblongata of the brain.
The sympathetic and parasympathetic divisions of the autonomic system regulate heart rhythm by affecting the same intrinsic impulse conducting mechanisms that lie within the heart in opposing ways.
What is cardiac output?
It is the work done by the heart and is defined as the volume of blood pumped from the heart every minute.
The determinants of cardiac output are stroke volume (SV) and heart rate (HR).
What is stroke volume and heart rate?
The amount of blood ejected from the ventricles every beat and heart rate is the number of times the heart beats in a minute.
What is the formula to calculate cardiac output?
CO = SV x HR
(cardiac output = stroke volume x heart rate)
Name the 5 types of vessels in the circulatory system.
- arteries
- arterioles
- capillaries
- venules
- veins
What is the main feature of arteries?
They carry blood away from the heart.
The pressure exerted on them is considerably higher than in other vessels.
What are arterioles?
As the arteries branch and subdivide, they become smaller. The smallest of these arteries are the arterioles. Although microscopic, they still contain smooth muscle and elastic fibres, albeit in relatively small amounts.
