Cardiovascular System Flashcards
A closed system of the heart and blood vessels
cardiovascular system
allow blood to circulate to all parts of the body
blood vessels
pumps blood
heart
Functions of the cardiovascular system
Transport:
oxygen
nutrients
cell wastes
hormones to and from cells
heart size
human fist
heart weight
less than a pound
location of heart
thoracic cavity, between the lungs in the inferior mediastinum
orientation of apex
- directed toward left hip
- rests on the diaphragm
orientation of base
- points toward right shoulder
- at level of 2nd rib
coverings of the heart
pericardium (parietal and visceral)
a double-walled sac
pericardium
is loose and superficial
Fibrous pericardium
deep to the fibrous pericardium and composed of two layers
Serous membrane
serous membranes
parietal pericardium
visceral pericardium
serous fluid
outside layer that lines the inner surface of the fibrous pericardium
parietal pericardium
next to heart; also known as the epicardium
visceral pericardium
fills the space between the layers of pericardium, called the pericardial cavity
serous fluid
Functions of pericardium
- Keeps the heart contained within the chest cavity
- Prevents the heart from over expanding when blood volume increases
- Limits heart motion
- Reduces friction between the heart and surrounding tissues
- Protects the heart against infection
Walls of the Heart
- epicardium (pericardium)
- myocardium
- endocardium
Outside layer; the visceral pericardium
epicardium
Middle layer; thickest layer of the heart
myocardium
myocardium is mostly what
cardiac muscle
the layer of the heart that contracts
myocardium
Inner layer known as endothelium
endocardium
Lines the inner heart chambers, covers heart valves and continuous with the endothelium of large blood vessels
endocardium
Four Chambers of the Heart
Atria
Ventricles
Receiving chambers
atria
Assist with filling the ventricles
atria
in the atria, blood enters through?
low pressure
Discharging chambers
ventricles
Thick-walled pumps of the heart
ventricles
in the ventricles, during ????, blood is propelled into circulation
contraction
Separates the two atria longitudinally
interatrial septum
Separates the two ventricles longitudinally
interventricular septum
Heart functions as a ??? pump
double
carry blood away from the heart
Arteries
carry blood toward the heart
Veins
Double pump
○ Right side works as the?
pulmonary circuit pump
Double pump
○ Left side works as the?
systemic circuit pump
- Blood flows from the right side of the heart to the lungs and back to the left side of the heart
○ Blood is pumped out of right side through the pulmonary trunk, which splits into pulmonary arteries and takes oxygen-poor blood to lungs
Oxygen-rich blood returns to the heart from the lungs via pulmonary veins
pulmonary circulation
carries oxygenated blood
arteries
carries unoxygenated blood
veins
serves as protection in backflow (catches blood)
valves in veins
major veins
superior and inferior vena cava
vein that receives blood from upper proximities
superior vena cava
vein that receives blood from lower proximities and lines the back
inferior vena cava
left or right?
receives unoxygenated blood
right atrium & ventricle
left or right?
receives oxygenated blood
left atrium/ventricle
valve between right atrium and right ventricle
tricuspid valve
pulmonary circulation (11)
- unoxygenated blood from superior & inferior vena cava
- right atrium
- tricuspid valve
- right ventricle
- pulmonic valve
- pulmonic artery
- lungs
- oxygenated blood to pulmonary vein
- left atrium
- bicuspid valve
- left ventricle
since arteries usually carry oxygenated blood and veins carry deoxygenated blood, in what circumstance is this reversed?
in the pulmonary artery and vein
systemic circulation (4)
- left ventricle
- aortic valve
- aorta
- different parts of the body
major artery
aorta
coronary circulation
from left ventricle, it has blood flow throughout the heart
Oxygen-rich blood returned to the left side of the heart is pumped out into the aorta
systemic circulation
has thicker walls because it pumps blood to the body through the systemic circuit
Left ventricle
in systemic circulation, Oxygen-poor blood returns to the right atrium via ???, which empty blood into the superior or inferior vena cava
systemic veins
Allow blood to flow in only one direction, to prevent backflow
heart valves
Valves open and close in response to ?
pressure changes in the heart
valves between atria and ventricles
atrioventricular valves
2 atrioventricular valves
bicuspid and tricuspid valve
Left AV valve:
bicuspid (mitral) valve
also known as mitral valve
bicuspid valve
Right AV valve:
tricuspid valve
Functions of AV valves
□ Anchored the cusps in place by chordae tendineae to the walls of the ventricles
AV valves open during
heart relaxation, when blood passively fills the chambers
AV valves closes during
ventricular contraction
valves between ventricle and artery
Semilunar valves
2 semilunar valves
§ Pulmonary semilunar valve
§ Aortic semilunar valve
SV valves close and open during?
□ Closed during heart relaxation
□ Open during ventricular contraction
Blood in the heart chambers does not nourish the ?
myocardium
- The heart has its own nourishing circulatory system consisting of: (3)
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
cardiac veins
a large vein on the posterior of the heart; receives blood from cardiac veins
coronary sinus
in cardiac circulation, Blood empties into the right atrium via the ?
coronary sinus
What makes the heart beat?
Intrinsic conduction system (nodal system) of the heart
○ Built into the heart tissue and sets its basic rhythm
○ Composed of specialized tissue
intrinsic conduction system
Causes heart muscle depolarization in one direction only (atria to ventricles)
intrinsic conduction system
intrinsic conduction system: Heart rate
75 beats per minute
contracts spontaneously and independently of nerve impulses
Cardiac muscle
contractions that occur in a regular and continuous way
Spontaneous contractions
spontaneous contractions: Atrial cells beat ??? times per minute
60
spontaneous contractions: Ventricular cells beat ??? times per minute
20−40
Intrinsic conduction system of the heart components include (4)
- sinoatrial node
- atrioventricular node
- atrioventricular bundle (bundle of His)
- purkinje fibers
[intrinsic conduction system]
□ Located in the right atrium
□ Serves as the heart’s pacemaker
sinoatrial node
[intrinsic conduction system]
is at the junction of the atria and ventricles
Atrioventricular (AV) node
Atrioventricular (AV) bundle is also known as
bundle of his
[intrinsic conduction system]
??? and bundle branches are in the interventricular septum
Atrioventricular (AV) bundle (bundle of His)
[intrinsic conduction system] spread within the ventricle wall muscles
Purkinje fibers
Intrinsic conduction system of the heart pathway
○ The sinoatrial node (SA node) starts each heartbeat
○ Impulse spreads through the atria to the AV node
○ Atria contract
○ At the AV node, the impulse is delayed briefly
○ Impulse travels through the AV bundle, bundle branches, and Purkinje fibers
○ Ventricles contract; blood is ejected from the heart
damage to AV node causes ventricles to beat at their own rate, which is much slower, some or all of the time
heart block
can be installed if there’s damage to SA node
artificial pacemakers
lack of adequate blood supply to the heart muscles
ischemia
rapid, uncoordinated quivering of the ventricles; makes the heart unable to pump blood
fibrillation
major cause of death from heart attacks in adult
fibrillation
rapid heart rate, over 100 beats per minute
tachycardia
slow heart rate, less than 60 beats per minutes
bradycardia
Normal heart rate=
60-100 bpm
refers to one complete heartbeat, in which both atria and ventricles contract and then relax
The cardiac cycle
systole
contraction
Diastole
relaxation
Average heart rate is approximately
75 beats per minute
Cardiac cycle length is normally
0.8 second
longer, louder heart sound caused by the closing of the AV valves
§ S1 (sound 1)
lub
short, sharp heart sound caused by the closing of the semilunar valves at the end of ventricular systole
§ S2
dup
sounds during heartbeat cycle (whooshing or swishing) made by turbulent blood in or near your heart
§ Not a disease but may/can indicate an underlying heart problem
§ S3 (usually not normal)
heart murmurs
Amount of blood pumped by each side (ventricle) of the heart in 1 minute
cardiac output (CO)
Volume of blood pumped by each ventricle in one contraction (each heartbeat)
stroke volume (SV)
About ?? ml of blood is pumped out of the left ventricle with each heartbeat
70
CO =
HR x SV
?? percent of blood in ventricles (about 70 ml/2 ounces) is pumped with each heartbeat
60
○ The critical factor controlling SV is how much cardiac muscle is stretched
○ The more the cardiac muscle is stretched, the stronger the contraction
starling’s law of the heart
is the important factor influencing the stretch of heart muscle
Venous return
plays a major role in increasing the venous return
Muscular pump
factors modifying basic heart rate (3)
neural (ANS) controls
hormones and ions
physical factors
Neural (ANS) controls: speeds heart rate
sympathetic nervous system
Neural (ANS) controls: primarily vagus nerve fibers, slow and steady the heart rate
parasympathetic nervous system
Hormones and ions: Epinephrine and thyroxine ?? heart rate
speeds
Hormones and ions: Excess or lack of (3) ions also modify heart activity
calcium, sodium, and potassium
Physical factors:
(4) influence heart rate
Age, gender, exercise, body temperature
Resting heart rate in fetus
140 – 160 beats per minute
Ave. heart rate adult females (???); male (???)
72 – 80;
64 – 72
???: heart and respiratory rate (increase)
Fever
form a closed vascular system that transports blood to the tissues and back to the heart
Blood vessels
Vessels that carry blood away from the heart
Arteries and arterioles
Vessels that play a role in exchanges between tissues and blood
Capillary beds
Vessels that return blood toward the heart
Venules and veins
layers (???) in blood vessels (except the capillaries)
tunics
Three layers (tunics) in blood vessels (except the capillaries)
tunica intima
tunica media
tunica externa
tunic: forms a friction-reducing lining
○ Endothelium
Tunica intima
tunic:
○ Smooth muscle and elastic tissue
○ Controlled by sympathetic nervous system
tunica media
tunic: forms protective outermost covering
○ Mostly fibrous connective tissue
○ Supports and protects the vessel
tunica externa
have a heavier, stronger, stretchier tunica media than veins to withstand changes in pressure
arteries
have a thinner tunica media than arteries and operate under low pressure
veins
??? of veins is larger than that of arteries
Lumen
“milks” blood in veins toward the heart
Skeletal muscle
○ Only one cell layer thick (tunica intima)
○ Allow for exchanges between blood and tissue
capillaries
capillaries form networks called capillary beds that consist of: (2)
A vascular shunt
True capillaries
Blood flow through a capillary bed is known as
microcirculation
Branch off a terminal arteriole
true capillaries
true capillaries empty directly into a
postcapillary venule
Entrances to capillary beds are guarded by
precapillary sphincters
Largest artery in the body
aorta
Leaves from the left ventricle of the heart
aorta
regions of aorta: leaves the left ventricle
Ascending aorta
regions of aorta: arches to the left
Aortic arch
regions of aorta: travels downward through the thorax
Thoracic aorta
regions of aorta: passes through the diaphragm into the abdominopelvic cavity
Abdominal aorta
Arterial branches of the ascending aorta: serve the heart
Right and left coronary arteries
vein that drains the head and arms
superior vena cava
vein that drains the lower body
inferior vena cava
Measurements of arterial pulse, blood pressure, respiratory rate, and body temperature
vital signs
Alternate expansion and recoil of a blood vessel wall (the pressure wave) that occurs as the heart beats
arterial pulse
Monitored at pressure points in superficial arteries, where pulse is easily palpated
arterial pulse
in superficial arteries, where pulse is easily palpated
pressure points
Pulse averages ? to ? beats per minute at rest, in a healthy person
70 to 76
Body sites where the pulse is most easily palpated
[artery]
- superficial temporal
- facial
- common carotid
- brachial
- radial
- apical
- femoral
- popliteal
- posterior tibial
- dorsalis pedis
The force that causes blood to continue to flow in the blood vessels
blood pressure
The pressure the blood exerts against the inner walls of the blood vessels
blood pressure
Two arterial blood pressures are measured
systolic, diastolic
pressure in the arteries at the peak of ventricular contraction
Systolic
pressure when ventricles relax
Diastolic
blood pressure is expressed as?
systolic pressure over diastolic pressure in millimeters of mercury (mm Hg)
normal blood pressure
120/80 mm Hg
is an indirect method of measuring systemic arterial blood pressure, most often in the brachial artery
Auscultatory method
is directly related to cardiac output and peripheral resistance
Arterial blood pressure (BP)
the amount of blood pumped out of the left ventricle per minute
Cardiac output CO
the amount of friction blood encounters as it flows through vessels
Peripheral resistance, PR
neural factors: has little to no effect on blood pressure
parasympathetic nervous system
neural factors: promotes vasoconstriction (narrowing of vessels), which increases blood pressure
Sympathetic nervous system
regulate blood pressure by altering blood volume
kidneys
If blood pressure is too high, the kidneys release ??? in the urine
water
If blood pressure is too low, the kidneys release ??? to trigger formation of angiotensin II, a vasoconstrictor
renin
Commonly believed that a diet low in salt, saturated fats, and cholesterol prevents what
hypertension (high blood pressure)
○ Low systolic (below 100 mm Hg)
○ Often associated with illness
○ Acute hypotension is a warning sign for circulatory shock
hypotension
○ Sustained elevated arterial pressure of 140/90 mm Hg
○ Warns of increased peripheral resistance
hypertension
fluid that is found between cells
Interstitial fluid (tissue fluid)
Substances move to and from the blood and tissue cells through
capillary walls
in an embryo: The heart develops as a simple tube and pumps blood by
week 4 of pregnancy
in an embryo: The heart becomes a four-chambered organ capable of acting as a double pump when?
over the next 3 weeks (after week 4 of pregnancy)
heartbeat is heard in an embryo when?
1 month of pregnancy
Carries nutrients and oxygen from maternal blood to fetal blood
umbilical cord
Fetal wastes move from and to?
fetal blood to maternal blood
umbilical cord houses: (2)
1 umbilical vein
2 umbilical arteries
carries nutrient- and oxygen-rich blood to the fetus
One umbilical vein
carry wastes and carbon dioxide–rich blood from the fetus to placenta
umbilical arteries
Age-related problems associated with the cardiovascular system include: (5)
- Weakening of venous valves
- Varicose veins
- Progressive arteriosclerosis
- Hypertension from loss of elasticity of vessels
- Coronary artery disease from fatty, calcified deposits in the vessels
