Cardiovascular System Flashcards
Closed system of heart and blood vessels
Cardiovascular system
Functions of the cardiovascular system
Transport oxygen, nutrients, cell wastes, hormones to and from cells
Main function of Cardiovascular system
Transportation
Allows blood to circulate to all parts of the body
Blood vessels
Transport vehicle of the cardiovascular system
Blood
Only fluid connective tissue in the body
Blood
Where can the heart be found?
Medial of lungs, specifically in the lower mediastinum; blood vessels starts at the 2nd rib until upper level of diaphragm
Position of the heart
Only in the anterior position of the body, posterior has the spine
Orientation of the heart
Tilted to the left side with apex/left ventricle facing the left
- Double-walled sac
- Keeps heart in place
- Made up of 3 layers
Pericardium
- Fibrous pericardium is loose and superficial
- Anchors heart to surrounding structure
Outer fibrous later
- Deep to the fibrous pericardium
- Slippery, two-layered
Inner serous membrane pair
Two layers of inner serous membrane pair
- Parietal pericardium
- Visceral pericardium
- Lines the interior of fibrous pericardium
- External
Parietal pericardium
- Internal, innermost layer of the pericardium; outermost layer of the heart wall
- Part of the heart wall
- Also known as epicardium
Visceral pericardium
Between parietal and visceral pericardium, contains the serous fluid
Pericardial activity
Produced by the serous pericardial membranes and collects in the pericardial activity
Lubricating serous fluid
What does the lubricating serous fluid do?
Allows the heart to beat easily in a relatively frictionless environment
Outside layer; aka visceral pericardium
Epicardium
- Middle layer
- Mostly cardiac muscle
- Skeleton of the heart
Myocardium
- Inner layer
- Creates smooth inner lining to allow smooth flow of blood within the heart
Endocardium
Inner layer of endocardium is also known as?
Endothelium
Thickest layer of the heart
Myocardium
Lines each chamber
Endocardium
Four hollow cavities of the heart
2 atria, 2 ventricle
Separates two atria longitudinally
Interatrial septum
Separates two ventricles longitudinally
Interventricular septum
Separates upper from lower portion
Coronary sulcus
Heart functions as a
Double pump
Primarily receiving chambers
Superior atria
Not important in pumping activity of the heart
Superior atria
Superior atria assist in filling the?
Ventricles
Inferior, thick-walled ventricles are the?
Discharging chambers or actual pumps of the heart
Allows blood to flow in only one direction and prevents backflow
Heart valves
Valve in between the atria and ventricle
Atrioventricular valve
Prevent backflow into the atria when the ventricles contract
AV Valves
Consists of two flaps, or cusps, of endocardium
Left AV valve, also known as the bicuspid valve or mitral valve
Has three cusps
Right AV valve, also known as tricuspid valve
Anchor the cusps to the walls of the ventricle
Chordae tendineae
When do the AV valves close and open?
Open during heart relaxation, closed during ventricular contraction
When do the semilunar valves close and open?
Closed during heart relaxation, open during ventricular contraction
Between ventricle and artery
Semilunar valve
Does the blood in the heart chambers nourish the myocardium?
No
It has its own nourishing circulatory system
Heart
What does the nourishing circulatory system of the heart consist of?
- Coronary arteries
- Cardiac veins
- Coronary sinus
Branch from the aorta to supply the heart muscle with oxygenated blood
Coronary arteries
Drain the myocardium of blood, collects deoxygenated blood
Cardiac veins
Large vein on the posterior of the heart; receives blood from cardiac veins, drains the blood from heart walls to atrium
Coronary sinus
Blood empties into the right atrium via the?
Coronary sinus
Functional blood supply that oxygenates and nourishes the myocardium is provided by the?
Right and left coronary arteries
Compressed when the ventricles are contracting and fill when the heart is relaxed
Coronary arteries and their major branches
Cardiac veins drains myocardium then empties into the?
Coronary sinus
Coronary sinus receives blood form cardiac veins and drains the blood from the heart walls to?
Right atrium
Contracts spontaneously and independently of nerve impulses
Cardiac muscle
How do spontaneous contractions occur?
In a regular and continuous way
Atrial cells beat faster because?
Small chamber
Ventricular cells beat smaller because?
Bigger chamber
Two systems that act to regulate heart activity
- Autonomic nervous system
- Intrinsic conduction system or nodal system
Beats per minute of atrial cells
60 beats per minute
Female: 60-83 beats per minute
Male: 70-90 beats per minute
Ventricular cells beats per minute
Beat 20-40 times per minute
Unifying control system
Intrinsic conduction system
System that involves involuntary movement
Autonomic Nervous System
- Sets the heart rhythm
- Composed of special nervous tissue
- Ensures heart muscle depolarization
- Regulate and monitor blood pressure
Intrinsic conduction system
Direction of heart muscle depolarization of the Intrinsic conduction systrm
Atria to ventricles
Heart rate of Intrinsic conduction system
Enforces a heart rate of 75 beats per minute
Starts each heartbeat (pacemaker)
Sinoatrial node
Rapid heart rate, over 100 beats per minute
Tachycardia
Slow heart rate, less than 60 beats per minute
Bradycardia
Prolonged tachycardia may progress to?
Fibrillation
Cardiac cycle refers to _______ heartbeat
1 complete heartbeat
Diastole means?
Relaxation
Systole means?
Contraction
Diastole and systole refers to?
It refers to contraction and relaxation of ventricles, unless other wise stated. This is because most pumping work is done by the ventricles.
Average heart beats
Approximately 75 times per. minute
Length of cardiac cycle
0.8 seconds
- Heart is relaxed
- Pressure in the heart is low - AV valves are open
- Blood is flowing passively through the atria into the ventricles
- Semilunar valves are closed
Atrial diastole (ventricular filling)
- Ventricles remain in diastole
- Atria contract
- Blood is forced into the ventricles to complete ventricular filling
Atrial systole
- Atrial systole ends, ventricular systole begins
- Initial rise in intraventricular pressure closes AV valves, prevents backflow of blood into atria
- For a moment, ventricles are completely closed chambers
Isovolumetric contraction
- Ventricles continue to contract
- Intraventricular pressure to surpass the pressure in the major arteries leaving the heart
- Causes the semilunar valves to open and blood to be ejected from the ventricles
- During this phase, the atria are again relaxed and filling with blood
Ventricular systole (ejection phase)
- Ventricular diastole begins
- Pressure in the ventricles falls below that in the major arteries
- Semilunar valves close to prevent backflow into the ventricles
- For another moment, the ventricles are completely closed chambers and intraventricular pressure continues to decrease
- Atria have been in diastole, filling with blood
- When ventricular pressure falls below atrial pressure, the AV valves open, and the cycle repeats
Isovolumetric relaxation
- Longer, louder heart sound
- Caused by closing of AV valves
Lub
- Short, sharp heart sound, snapping sound
- Caused by the closing of semilunar valves at the end of the ventricular system
Dup
Amount of blood pumped out by each side of the heart in 1 minute
Cardiac output
Volume of blood pumped out by a ventricle with each heartbeat
Stroke volume
Product of the heart rate and stroke volume
Cardiac output
Higher stroke volume, ________ heart rate
Lower
Lower stroke volume, ________ heart rate
Higher
Heart rate is typically how many beats per minute?
75 beats per minute
Stroke volume: The more the heart is stretched, the more ________ is being received by the chamber
Blood
Stroke volume: The more blood the chamber has, the stronger ________ is needed
Pump mechanism
About _______ is pumped out of the left ventricle with each heartbeat
70 mL of blood
Important factor influencing the stretch of heart muscle
Venous return
The critical factor controlling stroke volume is how much the cardiac muscle cells are stretched by the filling of the chambers just before they contract
Preload
Frank-starling law of the heart: The more the muscle cells are stretched, the ________ the contraction, and the ________ the stroke volume.
Stronger; higher
Two things influencing preload
- Amount of venous return (blood returning to the heart)
- Length of time the ventricles are relaxed and filling (determined by heart rate)
Three factors influencing stroke volume
- Preload
- Contractility
- Afterload
Low venous return, such as might result from __________ or an __________, decreases stroke volume
Sever blood loss; abnormally rapid heart rate
Anything that __________ the volume or speed of venous return also _________ stroke volume and force of contraction
Increases; increases
- Ability of cardiac muscles to generate tension
- Influenced by factors other than stretch, including the amount of calcium ions present, sympathetic nervous stimulation, and hormones such as epinephrine and thyroxine
Contractility
As contractility _________, stroke volume _________
Increases; increases
- Amount of pressure ventricles must overcome to eject blood
- Determined by the blood pressure in the pulmonary trunk and aorta pressing back on the semilunar valves
Afterload
If afterload ________, it will be more difficult for the ventricles to pump blood, and stroke volume will ________
Increases; decrease
- Sympathetic nervous system speeds heart rate
- Parasympathetic nervous system, primarily vagus nerve fibers, slow and steady heart rate
Neural (ANS) controls
- Epinephrine and thyroxine speed heart rate
- Excess or lack of calcium, sodium, and potassium ions also modify heart activity
Hormones and ions
Age, gender, exercise, body temperature influence heart rate
Physical factors
Resting heart rate is fastest in?
Fetus (140-160bpm)
Resting heart rate for male and female
Female: 72-80 bpm
Male: 64-72 bpm