Cardiovascular System Flashcards
double-layered sac that anchors and
protects heart
Pericardium
membrane around heart’s cavity
Parietal pericardium
membrane on heart’s surface
Visceral pericardium
space around heart
Pericardial cavity
surface of heart (outside)
Epicardium
thick, middle layer
composed of cardiac
muscle
Myocardium
smooth, inner surface or
endothelium
Endocardium
- 1 centrally located nucleus • Branching cells • Rich in mitochondria • Striated (actin and myosin) • Ca2+ and ATP used for contractions • Intercalated disks connect cells
Cardiac Muscle
4 Chambers
- left atrium (LA)
- right atrium (RA)
- left ventricle (LV)
- right ventricle (RV)
separates atria from
ventricles
Coronary sulcus
Upper portion • Holding chambers • Small, thin walled • Contract minimally to push blood into ventricles
atria
separates right and left atria
Interatrial septum
- Lower portion • Pumping chambers • Thick, strong walled • Contract forcefully to propel blood out of hear
Ventricles
separates right and left
ventricles
Interventricular septum
between atria and ventricles
Atrioventricular valves (AV)
- AV valve between RA and RV
- 3 cusps
Tricuspid valve
- AV valve between LA and LV
- 2 cusps
Bicuspid valve (mitral)
Semilunar valves:
pulmonary
aortic
base of pulmonary trunk
pulmonary
base of aorta
aortic
- Anchored the cusps in place by chordae tendineae to the walls of the ventricles
– Open during heart relaxation, when blood passively fills the chambers
– Closed during ventricular contraction
• AV valves
– Closed during heart relaxation
– Open during ventricular contraction
semilunar valves
- carries blood from heart to lungs
- blood is O2
poor, CO2
rich
pulmonary circuit
• Right Atrium:
- receives blood from 3 places:
superior vena cava
inferior vena cava
coronary sinus
receives blood from 3 places: superior
and inferior vena cava and coronary sinus
Right Atrium
drains blood above diaphragm (head,
neck, thorax, upper limbs)
Superior vena cava
drains blood below diaphragm
abdominopelvic cavity and lower limbs
Inferior vena cava
drains blood from myocardium
coronary sinus
- opens into pulmonary trunk
Right Ventricle
splits into right and left pulmonary
arteries
Pulmonary trunk
carry blood away from heart to lungs
Pulmonary arteries
- carries blood from heart to body
- blood is O2
rich, CO2
poor
systemic circuit
4 openings (pulmonary veins) that receive blood from lungs
left atrium
- opens into aorta
- thicker, contracts more forcefully,
higher blood pressure than right
ventricle has to get to body
left ventricle
carries blood from LV to body
aorta
The heart has its own nourishing circulatory system
consisting 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
Cardiac veins
a large vein on the posterior of
the heart; receives blood from cardiac veins
Coronary sinus
- supply blood to heart wall
- originate from base of aorta (above aortic semilunar valve)
Coronary arteries
- originates on right side of aorta
- supply blood to right ventricle
Right coronary artery
- has 3 branches
- supply blood to anterior
heart wall and left ventricle
Left coronary artery
Atrial cells beat times per minute
beat 60 times per minute
Ventricular cells beat times per minute
beat 20-40 times per minute
Need a unifying control system
the intrinsic conduction system (nodal system)
Two systems regulate heart activity
•Autonomic nervous system
•Intrinsic conduction system, or the nodal
system
Path of Action Potential through Heart
1 Sinoatrial node (SA node): 2 Atrioventricular (AV) Node 3 Bundle of His 4 Right and Left bundle branches 5 Purkinje fibers
rapid heart rate,
over 100 beats per minute
Tachycardia
slow heart rate,
less than 60 beats per minutes
Bradycardia
Heart is 2 side by side pumps
right and left
primers for pumps
atria
power pumps
ventricles
repetitive pumping action which includes contraction and relaxation
refers to one complete heartbeat, in which both atria and ventricles
contract and then relax
cardiac cycle
contraction of atria
• Atrial systole
contraction of
ventricles
Ventricular systole
relaxation of atria
Atrial diastole
relaxation of ventricles
ventricular diastole
Average heart rate is approximately beats per minute
75 beats per minute
Cardiac cycle length is normally second
0.8 seconds
longer, louder heart sound caused by the closing of the AV valves
Lub
short, sharp heart sound caused by the closing of the semilunar
valves at the end of ventricular systole
Dupp
• Factors modifying basic heart rate
1 neural (ans) controls
2 hormones and ions
3 physical factors
•Sympathetic nervous system speeds heart rate
•Parasympathetic nervous system, primarily vagus nerve
fibers, slow and steady the heart rate
neural (ans) control
•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
