Term 3: Internal Transport Flashcards
What is pulmonary circulation?
De-oxygenated blood from the tissues flows through the heart to the lungs in order to pick up oxygen. The oxygenated blood is then returned to the heart.
What is systemic circulation?
Oxygenated blood from the lungs flows through the heart to the tissues and rest of the body. The de-oxygenated blood then returns to the heart.
Pulmonary circulation occurs in the two left chambers of the heart. True or False?
False. It occurs in the two right chambers.
What are the four chambers of the heart called?
Left atrium, right atrium, left ventricle and right ventricle.
Systemic circulation occurs in which two chambers of the heart?
The left atrium and left ventricle
Name the four valves in the heart.
Where are each of them?
- The mitral or bicuspid valve between the left atrium and left ventricle.
- The tricuspid valve between the right atrium and right ventricle.
- The aortic valve between the left ventricle and the aorta.
- The pulmonary valve between the right ventricle and the pulmonary artery.
What is the main function of the valves in the heart?
To ensure the flow of blood in one direction and to prevent back flow into the chambers of the heart.
The four valves are known as what?
The atrioventricular (AV) valves and semi lunar valves (pulmonary and aortic semilunar)
How does blood flow?
It flows in response to a change in pressure from one area to another eg. from the atrium to the ventricle or the ventricle to the aorta. As pressure occurs blood moves, from an area of high concentration to an area of low.
In systemic circulation what do oxygen and carbon dioxide do?
O2 leaves the blood capillaries and diffuses into the capillaries surrounding the tissues.
CO2 diffuses from the tissues capillary beds into the blood capillaries
What are the two major vessels that return de-oxygenated blood to the heart?
The superior and inferior vena cava
The bicuspid or mitral valve is where?
Between the left atrium and left ventricle
Which two chambers of the heart pump oxygenated blood?
The left atrium and left ventricle
What does systole mean?
It is the contraction phase of the cardiac cycle
What is the cardiac cycle?
It is the series of events from the beginning of one heartbeat to the beginning of the next heartbeat. It involves two distinct actions systole (contraction) and diastole (relaxation).
What is the relaxation phase of the cardiac cycle called?
Diastole
What do the atrioventricular valves do?
Prevents back flow of blood into the atria
What brings the de-originated blood to the lungs?
The pulmonary trunk which then splits into separate arteries called the pulmonary arteries.
What separates the left and right atria?
The interatrial septum
What do the semilunar valves do?
Prevents back flow of blood into the ventricles
During relaxation the blood enters the left atrium via…?
The pulmonary vein
Describe the shape and size of the heart?
A hollow cone shape. About the size of your fist .
What is the name of the gradient that controls the flow of blood?
A pressure gradient
Pressure is created by what?
Pressure is created by blood being forced into a compartment and other muscle that surrounds the compartment. Eg. Before blood can move into the ventricle the valves close the chambers off so blood only flows into the atria. As the blood fills the atria, pressure will increase. When the pressure in the atria is higher than in the ventricle, blood then forces the valves open and blood flows into the ventricle.
What are the three layers of muscle in and around the heart?
The endocardium, myocardium and the epicardium
What does the myocardium consist of?
Myo-centre. This thick layer of cardiac muscle is the layer of the heart in which the majority of work occurs. It contains cardiac muscle tissue, blood vessels and nerves.
Where does the heart lie?
It lies in the pervasive sac, between the lungs, anterior to the vertebra and posterior to the sternum.
The heart is on a slight angle, it’s points towards the right shoulder and the apex points towards the left hip.
The pericardium consists of what?
It consists of 2 layers: the fibrous and serous pericardium.
The outer layer of the pericardium is called the fibrous layer. True or False?
True.
The outer layer: fibrous layer attaches the heart to the diaphragm and sternum
What does the inner serous layer form?
A double membrane. The two layers form a space called the pericardium cavity and secrete fluid that permits the layers to brush or move over each other as the heart contracts/beats.
What are the three events of the cardiac cycle?
- Atrial systole: atria contract/ventricle relax and blood is ready to be pushed into the ventricles.
- Ventricle systole: ventricle begin contraction/atria are relaxed, pressure begins to build in the ventricles pushing the semilunar valves open and blood is forced into circulation.
- Complete diastole: is the point where the whole heart is relaxed and the cardiac cycle starts again
What is the endocardium?
Endo-inner. The inner layer of muscle that lines each of the 4 chambers of the heart including valves to ensure blood flows through the chambers of the heart.
The epicardium is the outer layers. True or false?
True.
Epi-outer. This visceral layer of the pericardium consists of connective tissue (CT) that is attached to the myocardium.
What is the importance of the serous fluid?
It ensures the heats beats without friction of resistance. Without this serous fluid, friction will occur and the heart will have difficulty in its ability as a pump.
Also the loss of serous fluids can result in inflammation of the pericardium called pericarditis.
How is cardiac muscle similar to skeletal muscle?
Cardiac muscle cells are unique but share some similarity with skeletal muscle - including a striated appearance and think/thin filaments.