The Heart Flashcards
3 types of blood vessels
Arteries- carry blood away from heart
Veins- carry blood to heart
Capillaries- site of exchange between blood and tissue
Systemic circuit
Carries blood to and from the body
Right atrium and left ventricle
Pulmonary circuit
Carries blood to and from the lungs
Right ventricle and left atrium
Coronary sulcus
Divide atria and ventricles
Anterior and posterior interventricular sulcus
Separate left and right ventricles
And contain blood vessels of cardiac muscle
Layers of heart
Epicardium—outer visceral pericardium
Myocardium— muscle wall cardiac muscle tissue
Endocardium- simple squamous epithelium
Characteristics of cardiac muscle cells
Small size
Single central nucleus
Branching connections between cells
Intercalated discs
Foramen ovale
Before birth is an opening through interatrial septum
Connects two atria
Seals off at birth forming fossa ovalis
The right atrium receives blood via
Superior vena cava— head, neck, upper limbs, and chest
Inferior vena cava—trunk, lower limbs and viscera
Coronary sinus—cardiac veins return blood to coronary sinus and it opens into right atrium
The right atrium has what type of muscles
Pectinate muscles that are muscle ridges on anterior atrial wall and inner surface of right auricle
Chordate tendineae attaches to papillary muscles of right ventricle
This prevents backflow
Right artioventricular AV valve
Tricuspid valve— opens from right atrium to right ventricle
3 cusps
Prevents backflow during systole(contraction)
Pulmonary trunk divides into?
And has what type of valve
Left and right pulmonary arteries
Has pulmonary valve (semilunar valve)
The left atrium receives blood from?
What valve does it pass through?
Right and left pulmonary veins
Passes through bicuspid valve
Blood leaves left ventricle through?
Ascending Aorta , that turns into aortic arch and turns into descending aorta
Blood supply to heart
Coronary circulation
Blood to muscle tissue of heart
Coronary arteries and cardiac veins
Right coronary artery
Supplies blood to right atrium and both ventricles
Marginal arteries and posterior interventricular artery
Two main branches of left coronary artery
Circumflex artery
Anterior interventricular artery
Arterial anastomoses
Connect posterior and anterior interventricular arteries
So that 02 and blood get to cardiac muscle
Cardiac veins
Great cardiac vein
Anterior and posterior cardiac veins
Coronary ischemia
Reduced circulatory of O2 from complete or partial blockage of coronary arteries
The cardiac cycle begins
With electrical stimuli at SA node in right atrium transmitted through conducting system
What is the conducting system and how does it contract?
A system of specialized cardiac muscle cells that initiate and distribute the electrical impulses stimulating contraction
They contract automatically due to pacemaker cells
Structures of conducting system
Sinoatrial (SA) node
Atrioventricular (AV) node
Conducting cells- throughout myocardium
P wave
Atria depolarize
QRS complex
Ventricle depolarization
T wave
Ventricle repolarization
Absolute refractory period
Long, cardiac muscles can’t responds because calcium is going into cell
Relative refractory period
Short and cell can respond to stimuli
The cardiac cycle
Period between the start of one heart beat and the beginning of the next
Includes contraction and relaxation
End-diastolic volume
EDV
Largest amount of blood volume in chamber.
Atrial systole ends
Stroke volume
SV
The amount of blood ejected by ventricle into blood vessels
EDV-ESV=SV
End-systolic volume
ESV
Smallest volume of blood in chamber
Because of ventricle systole
S1 sounds
Heard when tricuspid and bicuspid valves close
S2 sounds
Heard when aortic and pulmonary semilunar valves close
Factors that affect cardiac output
Heart rate and stroke volume
Factors the affect your heart rate
Hormones and autonomic nervous system
Factors that affect your SV
EDV and ESV
Cardioacceleratory center
Sympathetic neurons control this. Increases heart rate
Cardioinhibitory center
Parasympathetic control. Slows heart rate
Atrial reflex
Bainbridge reflex
Adjust heart rate in response to venous return
When stretch reaches a certain level atria will contract
Preload
The degree of stretching during ventricle diastole
Directly proportional to EDV
Frank starling principle
As EDV increases, SV increases
