Cardiovascular System Flashcards
Arteries
Carry blood away from heart
Arterioles
Are the smallest branches of arteries
Veins
Return blood to heart
Venules
Collect blood from capillaries
Capillaries
Small, thin-walled vessels between smallest arteries and veins
Vascular pathway of Blood flow
Arteries -> Arterioles -> Capillaries -> Venules -> Veins
Functions of cardiovascular system
1) Transport. Deliver oxygen and nutrients to cells and tissues. Remove carbon dioxide and other waste products from cells and tissues
2) Protection. Carries cells and chemicals of immune system
3) Regulation. Homeostatis
Location of the heart
Thorax, behind the sternum, behind the lungs in the inferior mediastinum, a space between the two pleural cavities.
Orientation of the heart
Pointed apex directed toward left hip
Base points toward right shoulder
Covering and walls of the heart
Pericardium which is a double-walled sac that surrounds the heart.
Serous membrane that surrounds the heart and lines the pericardial cavity has two parts
- Parietal pericardium
: outer layer, lines surface of the pericardial cavity - Visceral Pericardium (epicardium) : inner layer, covers the heart
Parietal pericardium
outer layer, lines the surface of the pericardial cavity
Visceral pericardium / Epicardium
inner layer, covers the heart
What fills the space between the layers of pericardium?
Pericardial fluid
inner layer, covers the heart
Visceral pericardium / Epicardium
outer layer, lines the surface of the pericardial cavity
Parietal pericardium
Space between the layers of pericardium
Pericardial fluid
Three layers of the heart wall
- Epicardium
- Myocardium
- Endocardium
Epicardium
Outside layer made of connective tissue
Myocardium
Middle layer. It mostly contains cardiac muscle
Endocardium / Endothelium
Inner layer known as endothelium
Four chambers of the heart
Left atrium, right atrium, left ventricle, right ventricle
Name of part that separates the two ventricles
Interventricular septum
Name of part that separates the two atria
Interatrial septum
Difference between right ventricle and left ventricle
Right ventricle- thinner myocardium/ wall Lower pressure system Pump blood only to lungs Left ventricle - Very thick myocardium/ wall Produces 4-6 times as much pressure than right Pumps blood to aorta and then to the whole body
Name the part of the hearts
.
Functions of heart valves
To prevent backflow of blood.
Atrioventricular valves
Between atria and ventricles
- Bicuspid valve/ mitral valve (left side of the heart)
- Triscupid valve (right of the side of the heart)
Open during heart relaxation and closed during ventricular contraction.
Bicuspid valve / mitral valve
Left side of the heart
Tricuspid valve
right side of the heart
Atrioventricular valves are anchored in place by
chordae tendineae
Semilunar valves
Between ventricle and artery
- pulmonary semilunar valve
- Aortic semilunar valve
Closed during heart relaxation but open during ventricular contraction.
Four Heart valves
- Biscupid/Mitral valve
- Tricuspid valve
- Pulmonary semilunar valve
- Aortic semilunar valve
How do the first heart sound “lubb” arrives?
Due to the AV valves closing
What causes the Second heart sound “dubb”
due to the semilunar valves closing
How does the third and fourth heart sounds arrive?
Due to the atrial contraction and blood flow into ventricles
Difference between pulmonary circulation and systematic circulation
Pulmonary circulation moves blood between the lungs and the heart while Systematic circulation moves blood between the heart and the rest of the body
Describe what happens during pulmonary circulation
From the right ventricle, blood leaves the heart as it passes the pulmonary semilunar valve into the pulmonary trunk
Pulmonary trunk splits into right and left pulmonary arteries, which carry blood to the lungs.
In the lungs, gaseous exchange occurs where blood picks up oxygen and drops off CO2
Oxygen-rich blood returns to the heart through the four pulmonary veins
Describe what happens during systematic circulation
Oxygen-rich blood returns to heart through the four pulmonary veins
Blood enters the left atrium and travels through the bicuspid valve into the left ventricle
From the left ventricle, blood leaves the heart via the aortic semilunar valve and aorta.
Substances move to and from the blood and tissue cells through the capillary walls
Deoxygenated blood will travel via the superior and inferior vena cava and reach the right atrium
The path of blood flow
Deoxygenated blood will travel via the superior and inferior vena cava and reach the right atrium
Blood enters the right atrium and travels through the tricuspid valve into the right ventricle
From the right ventricle, blood leaves the heart as it passes the pulmonary semilunar valve into the pulmonary trunk
Pulmonary trunk splits into right and left pulmonary arteries, which carry blood to the lungs.
In the lungs, gaseous exchange occurs where blood picks up oxygen and drops off CO2
Oxygen-rich blood returns to the heart through the four pulmonary veins
Blood enters the left atrium and travels through the bicuspid valve into the left ventricle
From the left ventricle, blood leaves the heart via the aortic semilunar valve and aorta.
Substances move to and from the blood and tissue cells through the capillary walls
The heart had its own nourishing circulatory system consisting of :
- Coronary arteries - branch from the aorta to supply the heart muscle with oxygenated blood
- Cardiac veins - drain the myocardium of deoygenated blood
- Coronary sinus- a large vein on the posterior of the heart, received blood from the cardiac veins
Blood empties into the right atrium via the coronary sinus.
Left and right coronary arteries originate at _______.
base of aorta
Branches of right coronary arteries
marginal and posterior interventricular arteries
Branches of left coronary arteries
Circumflex and anterior interventricular arteries (LAD - left anterior descending artery)
Anastomoses
Interconnections formed between artery. It is to provide alternate pathways for blood supply to cardiac muscle.
Two types of cardiac muscle cells
- Contractile cells
- Conducting system
How is cardiac muscle activity initiated?
Cardiac muscle activity is initiated and controlled by movements of ions across the cell membrane
Cardiac conduction system
Network of specialised cardiac muscle cells that initiated a stimulus to contract
Once SA node starts the heartbeat. Impulse spreads to the AV node. Then the atria contract.
At the AV node, the impulse passes through the AV bundle, bundle branches, and Purkinje fIbers
Blood is ejected from the ventricles to the aorta and pulmonary trunk as the ventricles contract.
heart’s pacemaker
Sinoatrial node (SA)
What is an Electrocardiogram (ECG/EKG)
Recording of heart’s electrical activities from body surface by placing electrodes.
P Wave
Represents atrial contraction. Impulse is generated at pacemaker SA Node
QRS Complex
Represents ventricular contraction
T WAVE
Represents ventricular relaxation
Systole
Contraction
Diastole
Relaxation
Contraction
Systole
Systole
Contraction
Cardiac cycle
Period between start of one heartbeat and the next
heart rate
Number of beats per minute
Sequence of contractions
Atria contract together first : atrial systole. Push blood into the ventricles. Ventricles relaxed.
Ventricles contract together next : Ventricular systole. Push blood into the pulmonary and systematic circuits. Atria are relaxed.
Typical cardiac cycle last
800 msec
Atria contract together first
atrial systole
Ventricle contract together next
ventricular systole
Stroke volume (SV)
Volume of blood pumped by each ventricle in one contraction
Cardiac output (CO)
Amount of blood pumped by each side ventricle of the heart in one minute
HR x SV
Cardiac output (CO)
CO =
HR x SV
Factors affecting heart rate
Autonomic innervation, hormones
Factors affecting stroke volume
End-diastolic volume, End-systolic volume
Regulation of cardiovascular functions
- Blood volume reflexes and auto regulation
- Hormones and ions
- Physical factors
- Neural controls
Blood volume reflexes
- Atrial reflexes
- Frank-Starling principle
Atrial reflexes
Adjusts HR in response to increase in venous return
An autonomic sympathetic response to wall stretch
Venous return
flow of blood back to the heart.
Frank- starling principle
Increase in venous returns leads to:
- Increase stretch on myocardial cells
- Cells responds by contracting harder, increasing cardiac output
Peacemaker cells - autonomous or no?
autonomous
Heart has dual innervation from the autonomic nervous system which has two parts :
- Sympathetic nervous system- releases Norepinephrine. Increases heart rate and stroke
volume
2.Parasympathetic nervous system releases Acetyl Choline -> slow heart rate and stroke volume
Cardioacceleratory center is sympathetic or parasympathetic
symphatetic
Cardioinhibitory center
parasymphatetic
Baroreceptor reflexes
Receptor monitor degree of stretch elicited by blood pressure.
Very sensitive to ensure adequate flow to and perfusion of brain
Receptors are located at
- aortic sinuses
- carotid sinuses
Neural controls consist of
Autonomic nervous system
- Sympathetic nervous system
- Parasympathetic nervous system
Baroreceptor
reflexes and chemoreceptor reflexes
Chemoreceptor reflexes
Receptors sensitive to changes in CO2, O2 and pH in blood and CSF and activates the cardiovascular regulatory center in mendulla oblongata
Where is chemoreceptor reflexes located at?
Located in carotid and aortic bodies and mendulla oblongata
Short-term
hormones and ions
Epinephrine and Norepinephrine cause rapid increase pf cardiac output and vasoconstriction
Long-term
hormones and ions
- Antidiuretic hormone (ADH), angiotensin - Raise BP when low
- Atrial Natriuretic peptide- lowers BP when too high
Systolic
Pressure at the peak of ventricular contraction
Diastolic
Pressure when ventricles relax
another word for High blood pressure
Hypertension
Hypertension can be treated with
diuretics
Atherosclerosis
A buildup of atherosclerotic plaque in the walls of the blood vessels .
Plaque narrow blood vessel diameter, decreasing blood supply to tissues
Can cause clots to form in the roughened walls of arteries
Names of clots caused by Atherosclerosis
- Thrombus
- Embolus
- Thromboembolism
thrombus
a clot that is stationary
Embolus
A clot that detaches and moves to distant sites
Thromboembolism
an embolus that had become lodged in a blood vessel.
Heart attack also known as
Myocardial Infarction
Heart attack is cause by
a blocked coronary artery.
angina pectoris
pain in the chest from a partially blocked coronary artery. It can be treated with drugs that dilate blood vessels.
Aneurysm
A ballooning of a blood vessel, most often the abdominal aorta or blood vessels in the brain
