Heart and Circulation Flashcards
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What are the five functions of the circulatory system?
- Transport of O2 and CO2
- Regulate Temprature
- Transport of hormones
- Prevention of blood loss (closed system)
- Protection from disease-causing microbes and toxic substances (Pathogens)
Why is it important that the circulatory system remains a closed system?
- Maintain constant pressure
- Prevent blood loss
What is the difference between the pulmonary system and the systemic system?
The pulmonary system exists between the heart and lungs and the systemic system exists between the heart and body.
What three major components consist of the circulatory system?
- Heart
- Blood vessels (Arteries, Veins, Capillaries)
- Blood
What are the two major functions of the heart?
- Pumping blood - important for transport and filtering
- Keeping oxygenated blood from de-oxygenated blood - This way each cell gets oxygen-rich blood and de-oxygenated blood can become oxygenated
What is the purpose and location of the pericardium?
The pericardium is a membrane around the heart in between the heart and the lungs. This is to prevent friction between the heart and lungs.
What is the basic rundown of heart structures?
- 4 Chambers
a. Right Atrium
b. Right Ventricles
c. Left Atrium
d. Left Ventricle - Made up of specialized cardiac cells
Which side of the heart receives de-oxygenated blood and from where?
The right side receives the deoxygenated blood through the right atrium and then is transferred to the right atrium where through the pulmonary artery is pumped to the lungs. Blood is originally pumped into the right atrium through the superior and inferior vena cava. The superior vena cava brings blood from the head chest and arms whereas the inferior vena cava brings blood from the rest of the body.
Which side of the heart receives and distributes oxygenated blood?
The left side receives oxygenated blood from pulmonary veins into the left atrium, then is pumped by the left ventricle into the aorta.
What are the 5 different types of blood vessels and what are their functions?
- Arteries - Thick muscular blood vessels which take blood away from the heart.
- Veins - Blood vessels with one-way valves which prevent the backflow of blood. Contrary to arteries which rely on pulses from the heart to move blood, veins rely and suction in from the heart as well as the muscles around the veins. Take blood toward the heart.
- Cappilaries - Microscopic blood vessels that allow for the diffusion of Oxygen and Carbon Dioxide. Very low pressure and move slowly
- Arterioles - Small arteries which eventually turn into capillaries. Made of small muscles named precapillary sphincters which can regulate the flow of blood to the capillaries
- Venules - transition vessels between capillaries and veins
What is the difference between a vasodilator and Vasoconstrictor
Vasodilators are chemicals that are nerves that expand the width of vessels.
Vasoconstrictors however cause precappilary spincters to constrict.
Why is the ability to regulate the size of precapillary sphincters important?
Regulate blood pressure
What are the 3 types of valves found in the heart?
- Atrioventricular valves
composed of the tricuspid(right side) and bicuspid(left side). Regulate blood flow to ventricles from atriums and prevent backflow of blood into atrium during ventricular contraction. - Semilunar valves
Found at the entrance to major blood vessels. Smaller valves with no muscular attachments. Has THREE flaps.
What accessory structure is found at both atrioventricular valves?
Chordae tendinae - String-like structure that prevents blood backflow into the atrium during ventricular contraction.
What makes the “Lubb” “Dubb” sound in the heart?
The AV valves and semi-lunar valves closing make the “Lubb” and “Dubb” sound. When the AV valves close it makes the ‘lubb’ sound and when the semi-lunar valves close it makes the ‘dubb’ sound.
What initializes the heartbeat?
A bundle of specialized cells known as the sinoatrial node located in the right atrium initiates the heartbeat.
What effect do the sinoatrial node electrical impulses have?
The SA node’s electrical signals cause heart muscles to contract.
What are the steps involved in heart contraction?
- The SA node generates electrical impulses and causes both atriums to contract simultaneously
- As the atrium contracts the signal reaches the atrioventricular node (AV) node which transmits the signal through specialized cells called the bundle of HIS.
- The bundle of HIS divides into fast-conducting Purkinje fibers.
- As the signal reaches the Purkinje fibers the ventricles contract.
What is the difference between Systole and Diastole?
Systole is when the ventricles contract and Diastole is when the atriums relax and drain into the ventricles.
During Systole what do the AV valves do?
The AV valves close making the ‘lubb’ sound.
What happens during Diastole?
The Semi-lunar valves close and the AV valves open. The semi-lunar valve closing makes the ‘dubb’ sound.
How is heart rate set?
The SA node sets the heart rate.
What are Bradycardia and, Tachycardia examples of?
These two are examples of different resting heart rates both of which are the extremes on the spectrum.
What is bradycardia?
Bradycardia is when a resting heart rate is <50 beats per/minute this could be bad if the body doesn’t not receive enough blood flow.
What is tachycardia?
This is when the resting heart rate exceeds 100 beats per minute. This could be bad as it could mean that the chambers may not fully fill with blood.
How is heartrate changed?
The heart rate is regulated by a feedback system including a monitor which detects change, a control center which sends out orders, and a regulator which brings about a change.
What is the difference between sympathetic and parasympathetic nerves?
Sympathetic nerves increase heart rate whereas parasympathetic nerves decrease heart rate.
What are some other factors which could increase heart rate?
- An increase in temperature
- An increase in the hormone epinephrine(adrenaline)
- Different chemicals such as carbon monoxide and alcohol.
How does CO2 affect heart rate and how is detected and changed?
If an increased amount of CO2 is detected chemoreceptors(monitor)in the Aorta and carotid arteries detect the change and send a nerve signal to the medulla oblongata(control center). The medulla oblongata send out sympathetic nerve impulses causing the heart to increase heart rate. The inverse happens if CO2 levels drop.
What is the purpose of an ECG?
An ECG is used to measure the change in electrical impulses produced as the heart relaxes and contracts.