Cardiovascular & Respiratory System Test Review Flashcards
Components and Function of Cardiovascular System
Composed of:
- Heart, blood vessels, blood
Functions:
- Delivery of O2, fuel, and nutrients, to the tissues of the body
- Removal of CO2 and waste products from the tissues
- Maintenance of a constant body temperature (thermoregulation)
- Prevention of infection (immune function)
Layers of the Heart
- Pericardium (protective sac)
- Epicardium (lies against pericardium)
- Myocardium (below epicardium, muscle layer)
- Endocardium (tissue inside)
What is the heart considered to be?
“Double pump.” Divided into the right and left heart; separated by the interventricular septum
Right Heart (Main Function)
Pumps deoxygenated blood (darker red) from the body to the lungs (pulmonary circulation)
Left Heart (Main Function)
Delivers oxygenated blood (bright red) from the lungs to the rest of the body (systemic circulation)
Heart Valves
4 valves in the heart ensure that blood flows along the proper path;
- Opening and closing the 4 chambers
- Consist of unidirectional flaps (AKA cusps or leaflets) that cause blood to flow in 1 direction only, preventing back flow
- From the atria into the ventricles, and out the ventricles through the vessels of systemic or pulmonary circulation
- Attached to the special muscular extensions of the ventricle walls (papillary muscles) by strands of tissue called the chordae tendinae
Pulmonary Semilunar Valve
Tricuspid, found between the right ventricle & pulmonary artery, prevents back flow from the PA into the RV
Aortic Semilunar Valve
Tricuspid, found between left ventricle & aorta, prevents back flow from the A into the LV
AV Bicuspid (Mitral) Valve
Bicuspid, found between the left atrium and left ventricle, prevents back flow from the LV to the LA
AV Tricuspid Valve
Tricuspid, found between the right atrium and right ventricle, prevents back flow from the RA into the RV
Pathway of Blood through the Heart
Superior and Inferior Vena Cava
Right Atrium
Tricuspid Valve
Right Ventricle
Pulmonary Semilunar Valve
Pulmonary Artery
Lungs
Pulmonary Veins
Left Atrium
Bicuspid (mitral) Valve
Left Ventricle
Aortic Semilunar Valve
Aorta
Arteries
Arterioles
Capillaries
Venules
Veins
Path of Electrical signal through the Heart
- SA node
- Atria
- Bottom of atria to the AV node
- Down ventricular septum
- Bundle of His
- Right and Left bundles
- Purkinje fibers
- Myocardium
SA Node
Region of tissue found in the right atrium. Heart’s “pacemaker” because it is the location where electrical signals are initiated
Internodel Pathways
What the electrical signal travels through in the atria
AV Node
Located at the bottom of the atria which transmits the signal into the ventricles.
Bundle of His
Region of tissue that separates the 2 ventricles and spilts to form the right and left bundle branches
Purkinje Fibres
Branched fibres that carry the electrical signal to the ventricles
Arteries
Blood vessels that carry blood away from the heart. In systemic circulation, arteries carry oxygenated blood from the left side of the heart towards body tissues. In pulmonary circulation, arteries carry deoxygenated blood from the right side of the heart towards the lungs.
Arterioles
The vessels in the blood circulation system that branch out from arteries to capillaries, where gas exchange occurs. Surrounded by smooth muscle, arterioles are the primary site of vascular resistance (smaller than arteries)
Capillaries
The smallest of the blood vessels and help to enable the exchange of water, oxygen, carbon dioxide, and other nutrients and waste substances between blood and the tissues.
Venules
Small thin-walled extensions of the capillaries that lead into the veins, which return blood to the heart from another trip throughout the vascular system.
Veins
Blood vessels that carry blood toward the heart. In systemic circulation, veins carry deoxygenated blood towards the right side of the heart from body tissues. In pulmonary circulation, veins carry oxygenated blood toward the left side of the heart from the lungs.
Pathway of the Vascular System
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
3 Ways: Skeletal Muscle Pump
- The first system used to assist in the return of blood in the veins to the heart.
- A general term used to describe how, with each contraction of skeletal muscle, blood is pushed or massaged that muscle.
- Occurs because of the one-way valves found in the veins. Each contraction of a muscle compresses the veins within or around the muscle, increasing pressure within that vein. The increase in pressure moves the blood along, and because of the one-way valves, the only direction the blood can travel is back toward the heart
3 Ways: Thoracic Pump
- The second system used to assist in the return of blood in the veins to the heart.
- Related to breathing. With each breath taken by the respiratory system, pressure in the chest cavity is very low for a few short seconds, while the pressure in the abdominal cavity increases.
- Creates a difference in pressure between the veins in these 2 body cavities, and pushes blood from the veins in the abdominal cavity into the veins in the thoracic cavity, because of the one-way valves found in the veins.
3 Ways: The Nervous System
- The final system used to assist in the return of blood in the veins to the heart.
- At times when cardiac output needs to be increased, such as during exercise, the nervous system sends a signal to the veins, causing them to slightly constrict (this response is known as vasoconstriction). The slight constriction helps to return more blood to the heart.