Structures and Functions of the Circulatory System Flashcards
What are the functions of the Circulatory System?
- Transports gasses and wastes
- Regulates internal temp, transports hormones
- Protects against blood loss from injury (platelets), provides immune response
The 3 major components of the Circulatory System are..
- Heart
- Blood Vessels
- Blood
Pumps blood through body, generates blood flow
Heart
- “Roadways” for blood
- Arteries, veins, and capillaries
Blood Vessels
Carries nutrients, O2, CO2, wastes, and other materials throughout the body.
Blood
Where is the heart located?
Slightly left of middle of chest
Two chambers at the top of the heart
Atria (singular = Atrium)
Two chambers at the bottom of the heart
Ventricles
Thick muscular wall that separates the heart from the middle
Septum
Fluid filled membrane surrounding the heart
Pericardium
Separates atria from ventricles
Atrioventricular (AV) Valves
Separates ventricles from arteries
Semilunar Valves
Why does the heart have one-way valves between atria, ventricles, aorta, and pulmonary arteries?
To ensure blood flows in the correct direction. (one direction)
What is deoxygenated blood?
- Shown on diagrams as blue (to separate from oxygenated blood)
- Blood returning from tissues
- Low O2 content (because its just delivered all its O2 to the tissues)
- Heading towards the heart & lungs to get more oxygen
What is Oxygenated blood?
- Blood leaving the lungs filled with O2
- Heading towards tissues to deliver O2
- O2 poor blood coming back from the body is pumped through the VENA CAVA (right side of heart) into the..
Right Atrium
- Blood flows from RIGHT ATRIUM to RIGHT VENTRICLE and then out the LEFT AND RIGHT…
Pulmonary ARTERIES
Pulmonary ARTERIES lead to the..
Lungs (for gas exchange)
- O2 rich blood from the LUNGS returns to the heart through LEFT AND RIGHT..
Pulmonary VEINS
- O2 rich blood enters the LEFT ATRIUM then the..
LEFT Ventricle
- O2 rich blood leaves the heart through the…
AORTA
The Aorta leads to..
the whole body
- Carries blood AWAY from the heart
- Highly Elastic walls
Arteries
DEOXYGENATED blood leaves the right side of the heart to the lungs via..
Pulmonary ARTERIES
OXYGENATED blood leaves the left side of the heart via..
AORTA
- Smallest blood vessels
- Walls are a single layer of cells
Capillaries
Site of gas, nutrient and waste exchange between blood and cells
Capillaries
- Carries blood TOWARDS the heart
- Not elastic, cannot contract to move blood back to the heart
- Relies on contraction from surrounding skeletal muscle
Veins
Has thinner walls than Arteries
Veins
Contains one-way valves to prevent back flow against gravity
Veins (unlike Arteries/except Arteries exiting the ventricles)
Deoxygenated blood returns to the RIGHT side of the heart via..
Vena Cava
Oxygenated blood returns to the LEFT side of the heart via..
Pulmonary Veins
Occurs when the leaflets of valves fail to close properly, causing blood to flow backwards and pool in the veins
Varicose Veins
Biggest Artery
Aorta
Small Arteries
Arterioles
Small Veins
Venuoles
The stimulus that triggers a heartbeat
An Electrical Signal
- Bundle of specialized nerves and muscle tissues.
- Acts as a pacemaker -sets rate of heartbeat (70bpm)-
Sinoatrial Node (SA Node)
Where is the SA Node located?
The wall of the right atrium.
Generates electrical signal that spreads over the two atria and them contract simultaneously
SA Node
Where is the AV Node located?
The bottom of the right atrium.
- Receives electrical signals from the SA Node
- Left and Right Ventricles contract simultaneously
Atrioventricular Node (AV Node)
AV Node transmits signal through the..
Bundle of His (Bundle of specialized nerve fibers)
The fibers in the AV Node relay signal through two branches of conducting fibers called..
Purkinjie Fibers
A device that records the electrical activity of the heart as it contracts and relaxes
Electrocardiogram (ECG)
What is the Electrocardiogram used for?
To diagnose certain heart problems. (looking at the graph and analyzing any abnormal line tracings).
Refers to heart relaxation (heart fills with blood)
Diastole
Refers to heart contraction (heart pumping blood out)
Systole
Sound produced when AV valves close. (When ventricles contract, blood is forced up and cause the AV valves to close).
Lubb
Sound produced when the Semi-lunar valves close
Dubb
What does the ECG wave part “P” mean?
Just before atrial contraction.
What does the ECG wave part “QRS” mean?
Electrical impulse that spreads through ventricles (ventricle contraction).
What does the ECG wave part “T” mean?
Ventricles recovering before next SA stimulation. (Atrial relaxation recovery/heart filling).
Where is the lubb sound heard on the ECG chart?
P to Q
Where is the dubb sound heard on the ECG chart?
S to T
What are the two measurements of blood pressure?
Systolic and Diastolic
Top, 120, Ventricles contract
Systolic
Bottom, 80, Ventricles relax
Diastolic
Pressure blood exerts during ventricular contraction.
Systolic blood pressure
Pressure blood exerts during Ventricular relaxation
Diastolic blood pressure
Amount of blood flowing from the heart each minute
Cardiac output
The quantity of blood pumped with each heartbeat (~70mL/beat)
Stroke Volume
Number of heart beats per minute (~70 beats per minute)
Heart Rate
When Cardiac Output is increased, is blood flow increased or decreased?
Increased
When Cardiac Output is decreased, is blood flow increased or decreased?
decreased
What are factors affecting cardiac output?
- Size of Individual
~Large mass = higher cardiac output Smaller mass = smaller cardiac output - Exercise
Vessels that carry blood to and from the lungs.
Pulmonary Circulation
Vessels that carry blood to and from the body.
Systemic Circulation
The heart’s separate blood supply that supplies cardiac muscles with O2 and other nutrients.
Coronary Pathway
Condition where there is a buildup of plaque (fatty deposits, calcium, and fibrous tissues) inside of the artery walls.
Narrowing = higher pressure which leads to angina, blood clots, shortness of breath, heart attack, and heart failure.
Atherosclerosis
How is Atherosclerosis treated?
- Aspirin - reduce formation of clots
- Clot busting medication
- Angioplasty (balloon inserted)
- Stent (permanent metal tube)
- Coronary bypass surgery (healthy artery creates a new pathway).
- Congenital (born with)
- Misflow of blood in the heart
- Valves not opening or closing properly
~Valve defects can be heard with a stethoscope - Problems in the walls of the chambers.
Heart Murmur
- High blood pressure: causes blood vessels to weaken or even rupture
- Results in build-up of connective tissue as body tries to repair, making arteries hard and less elastic
Hypertension
- Low blood pressure: reduces bodies ability to transport blood
- Problem for your brain because blood pressure has to work against the force of gravity to get up there
= dizzy spells
Hypotension
What is the relative velocity (speed) of the blood as it flows through the capillaries?
Slowest (single-file and time for gas exchange).
What happens to blood pressure as blood moves from the arteries to the veins?
The blood pressure lowers.
Why does the pressure change as blood moves from the arteries to the veins?
Arteries have muscular walls (higher pressure), Veins don’t have muscular walls.
What circulatory system organ is responsible for supplying the pressure for the blood?
The Heart
Which chambers are pumping chambers of the heart?
Atriums
Which chambers are the receiving chambers of the heart?
Ventricles
How do the walls of the atria compare with the walls of the ventricles and why are they different?
The walls of the atria are thinner than the ventricles because the ventricles use more power to pump blood throughout the body.
What is the purpose of heart valves?
So the blood doesn’t flow backwards (backflow).
Which artery is the largest and why?
The aorta because it carries O2 blood throughout the body.
Above what value is someone considered to have high blood pressure?
From a130/80 mm Hg or higher
From a medical perspective, what is the problem with having high blood pressure?
The chance of having a heart attack, and stroke are increased.
Below what value is someone considered to have a low blood pressure?
From 90/60 mm Hg or lower
From a medical perspective, what is the problem with having low blood pressure?
Some potential problems include dizziness, weakness, and fainting.