Chapter 22 - The Heart Flashcards
Purpose of the heart
propels blood through 100 000km of vessels and about 5L per minute
Cardiology
Study of the heart
Location of the heart
-center of the cardiovascular system
Arteries
carry blood away from the heart
Veins
carry blood back to the heart
Great Vessels
arteries and veins entering and leaving the heart
Heart Valves Purpose
ensure blood flow is unidirectional
Heart Structure
two side-by-side pumps that work at the same rate and pump the same volume of blood
Pumps
one goes to the lungs (pick up oxygen) and one goes to body tissue (deliver oxygen)
Blood Pressure
-heart generates BP through alternate cycles of contraction and relaxation
-the force of blood pushing against the inside walls of blood vessels
Pulmonary Circulation
-starts with the right side of the heart pumping deoxy blood through pulmonary arteries
Pulmonary Veins
carry blood to left side of the heart after O2 pickup and CO2 release
Systemic Circulation
left side of the heart pumps blood oxygenated blood through systemic arteries to bodys cells
Systemic Veins
carry blood back to the right side of the heart after waste/gas exchange
Pattern of blood flow
R side of heart-> lungs-> L side of heart-> systemic cells
Position of the Heart
-located slightly left of the midline
-deep to sternum
Mediastinum
Space that holds the heart
Right Border
located more anteriorly
Left Border
located more posteriorly
The base of the heart
-poserosuperior surface
-mainly the left atrium
The superior border of the heart
formed by the great arterial vessels and the superior vena cava
Apex
-located on diaphragm
-inferior conical end
Inferior Border
formed by the right ventricle
Pericardium
-double serous membrane that encloses the heart
-restricts movement slightly in the thorax
-2 parts:
Fibrous Pericardium
tough outer sac
Serous Pericardium
-composed of parietal and visceral layers
-free (not attached)
Pericardial Cavity
thin space between layers of serous pericardium containing serous fluid
Functions of Fibrous Pericardium
-made of dense irregular connective tissue
-prevents overstretching of the heart
-provides protection
-anchors heart to mediastinum
-**attached to thoracic cavity
Layers of Serous Pericardium
-outer: partietal
-serous fluid
-inner: visceral
Epicardium
-visceral layer of serous pericardium and areolar connective tissue
-most superficial layer
Myocardium
-cardiac muscle
-middle layer
-thickest layer
-responsible for beating and contraction
Endocardium
-internal surface of heart chambers
-simple squamous epithelium and areolar connective tissue
-deepest layer of the heart wall
Cardiac Muscle Intercellular Junctions
-intercalculated discs
=desmosomes (flexibility) + gap junctions (electrical signal)
4 Heart Chambers
-2 superior and smaller atria
-2 inferior and larger ventricles
Auricle
formed by the anterior part of each atrium
Blood Flow through heart
-R atrium to R ventricle, pulmonary trunk, pulmonary circulation
-L atrium to L ventricle, aorta, systemic circulaton
Heart Markings
-3 major surface markings, or grooves, called sulci
Sulci
-coronary blood vessels and fat
-mark the boundary between the two chambers of the heart
Coronary Sulcus
-marks boundary between atrium and ventricle
Anterior Interventricular Sulcus
-separates left and right ventricles
-anterior interventricular artery
Posterior Interventricular Sulcus
-separates ventricles on posterior side of the heart
-posterior interventricular artery
Right Atrium
forms the right border of the heart
Where Right Atrium received deoxy blood from
-superior vena cava
-inferior vena cava
-coronary sinus (from heart surface)
Pectinate Muscles
internal smooth muscle ridges on the atrial wall that expand to account for blood volume
Interatrial Septum
-contains fossa ovalis
-separates R and L ventricles
Fossa Ovalis
Tricuspid Valve
-right atrioventricular valve
-separates R atrium form right ventricle
Right Ventricle
-forms most of the anterior surface
-recieved deoxy blood from R atrium
Trabeculae Carneae
raised bundles of smooth muscular ridges
Papillary Muscle
-cone shaped muscular projections
-control valve
Chordae Tendineae
-strands of collagen fibers
-attaches to AV walls and papillary muscle
-open/close of valve w papillary muscle
Septomarginal Trabecula
secures papillary muscles to the interventricular septum
Pulmonary Valve
-separates R ventricle from pulmonary artery (deoxy blood to lungs)
Interventricular Septum
muscular wall that divides the hearts ventricles into the L and R halves
Pulmonary Trunk
-artery that transports deoxy blood from heart to lungs
Left Atrium
-forms most of the base of the heart (posterior part)
-receives oxygenated blood from the lungs
Pulmonary Veins
-two from each lung
-bring oxygenated blood into heart from the lungs
Bicuspid Valve
-aka mitral or Left AV valve
-separates chambers on L side of the heart
Left Ventricle
-thickest part of the heart
-forms the apex of the heart
-contains same trabeculae carneae and chordae tendineae
Conus Arteriosus
-smooth wall conical region
-cone shaped outflow tract of the ventricle
-lack trabeculeae
Aorta
-blood flows here from the left ventricle
Atria Characteristics
-thinner
-generate less pressure
-deliver blood a short distance
Ventricle Characteristics
-3x thicker
-generate more pressure
-L is thicker than R
Fibrous Skeleton
-dense irregular connective tissue in the heart wall
Functions of the Fibrous Skeleton
-prevent overstretching of the valves
-secure valves to heart wall
-point of insertion for bundles of muscle fibres
-electrical insulation between atria and ventricles
Purpose of Valves
-prevent backflow into the heart
Tricuspid Valve
-3 flaps
-aka Right AV Valve
Bicuspid Valve
-2 flaps
-aka Left AV Valve
Semilunar Valves
-allow ejection of blood from the ventricles
-prevent back flow back into heart
Pulmonary Valve
-between right ventricle and pulmonary artery
Aortic Valve
-separates left ventricle from aorta
Coronary Circulation (Arteries)
-coronary vessels pick up blood in the aorta and supply it to the two branches
Right Coronary Branches
- Right marginal artery
- Posterior interventricular artery
Right Marginal Artery
supplies the right border of the heart
Posterior Interventricular Artery
supplies posterior surfaces of the left and right ventricles
Left Coronary Artery Branches
- Anterior Interventricular Artery
- Circumflex Artery
Anterior Interventricular Artery
-aka left anterior descending artery
-supplies the anterior surface of both ventricles and most of the interventricular septum
Circumflex Artery
-supplies left atrium and ventricle
Cardiac Conduction System
-the power station
-specialized cells that start and propagate electrical impulses to contractile cells
Autorhythmic Cells
-1%
SinoAtrial Noden
-group of autorhythmic cardiac muscle fibers
-pacemaker
-Na+K+ channels are always open
Atrioventricular Node
Contractile Cells
-99%
Role of the Nervous System
-can alter the pace of contractions (along with certain hormones)
-does not initiate contractions
Autorhythmicity
-initiates its own heartbeats
Bundle of His
Purkinje Fibers