Heart Flashcards
Delivers blood to and from the lungs where it is oxygenated
Pulmonary circulation
send blood to all the tissues in the body, thus bringing oxygen to all the cells of the body and removing carbon dioxide
Systemic circulation
Position of the heart: In the \_\_\_\_ cavity \_\_\_ of midline \_\_\_ to sternum \_\_\_\_ to diaphragm Base of heart is around rib\_\_\_
Thoracic Left Posterior Superior Two
Region of the thoracic cavity between the lungs
Mediastinum
The posteriosuperior region of the heart is flat and called the____
Base
The inferior pointed end of the heart is called the ___
Apex
Heart is contained within a fibrous sac called the____
pericardium
Functions of the pericardium
- Anchors the heart inferiorly to the diaphragm and superiorly to the great vessels
- Restricts heart movement within thorax while allowing expansion and contraction
- Isolation from other thoracic organs
Two parts of the pericardium and associated tissue types:
- Outer fibrous pericardium (dense irregular connective tissue)
- Inner serous pericardium (simple squamous epithelium+thin layer of connective tissue)
Fibrous pericardium is attached
- Superiorly to the _____
- Inferiorly to the ____
- Large vessels exiting the heart
2. Diaphragm
The serous pericardium is divided into two layers (or really one layer folded onto itself). What are the two layers?
Parietal layer (lines the surface of the fibrous pericardium) Visceral layer (lines the surface of the heart)
The space between the parietal layer and visceral layer of the serous pericardium is?
Pericardial cavity
A thin _____lubricates the layers (parietal and visceral) so they move without friction
Percardial fluid
What layer of the serous pericardium lines the surface of the heart?
The visceral layer
Three layers of the wall of the heart:
- Epicardium
- Myocardium
- Endocardium
Layer made op of visceral layer of pericardium + accumulated fat
Epicaridium
Muscle layer of the wall of the heart (cardiac muscle)
Myocardium
Cardiac muscle cells:
Cardiocytes or myocytes
In wall of the heart -inner layer of simple squamous epithelium (called endothelium) + thin layer of connective tissue
Endocardium
Each atrium has an anterior flap-like extension called an _____
auricle (because it looks like an ear)
What does the auricle do for the atria?
It increases the volumn of the atria
On the external heart, the ____ separates the atria from the ventricles
coronary sulcus
On the external heart, the ______ separate the ventricles from each other (posterior and anterior)
interventricular sulci
Coronary arteries, on the external heart, vascularize the heart itself and originate from the ____
Aorta
Collagenous/elastic fibers found between each chamber of the heart. Offers structural support, anchors cardiocytes, anchors valves, acts as an electrical insulator
Fibrous skeleton
Valves are dense connective tissue “doors” that are lined by ____. Valves allow ____blood flow, prevents ____.
Endocardium
Unidirectional
Backflow
Atrioventricular (AV) valves close when ventricles ____
Contract
Two atrioventricular (AV) values:
- Right AV (tricuspid) valve
2. Left AV (formerly “bicuspid”) valve or mitral valve
Tendinous chords tether AV valves to ____.
Papillary muscles
Semilunar valves close when ventricles ___.
Relax
Two semilumar valves:
- Pulmonary valve – at exit of right ventricle
2. Aortic valve – at exit of left ventricle
3 vessels empty into the right atria:
superior vena cava, inferior vena cava, and the coronary sinus
The_____ is the thin wall between the atria
Interatrial septum
The interatrial septum has a depression called ____-a hole from the fetal period that closed.
fossa ovalis
Blood leaves the right atria through the atrioventricular (AV) opening when the _____opens.
AV valve (tricuspid valve)
The posterior wall of the right atrium is _____
The anterior wall is lined by ridges called _____
Smooth
Pectinate muscles
The _____ is a thick wall between the right and left ventricles
Intraventricular septum
The internal surface of both ventricles have large, smooth muscle ridges called _____
Trabeculae carne (meaty beams)
The AV valve is anchored to the ventricle walls by fibrous cords called _____
The_____ attach inferiorly to muscle projections called papillary muscles
Tendinous cords
The purpose of anchoring the valve flaps is to keep them from:
flipping backwards when the ventricle contracts
When the right ventricle contracts, it forces the blood upwards, through the ____, into the pulmonary trunk
The pulmonary trunk splits into pulmonary ____ that bring ____ blood to the lungs for gas exchange
Pulmonary semilunar valve
Pulmonary arteries
deoxygenated
The AV valve on the left is sometimes called the ___ or ___
Bicuspid or mitral valve
The wall of the_____ is the strongest and thickest of the 4 chambers. Usually 3x thicker than the other side
Left ventricle
___ pulmonary arties carry blood to the lungs. ___pulpmary viens carry blood to the heart.
Two
Four
The time from the start of one heartbeat to the start of the next
The cardiac cycle
The contraction of a heart chamber is ____. During systole, the cardiac muscle contracts, squeezing blood out of the chamber and into the next chamber or vessel.
Systole
The relaxation of the heart is called ____. During diastole the chambers relax and fill with blood
Diastole
Electrical events measured by ____
Electrocardiogram (ECG)
The ___ and ____ exit the aorta and feed the cardiac muscle itself.
They branch into progressively smaller blood vessels
left and right coronary arteries
_____return deoxygenated blood that ultimately merges into coronary sinus
Cardiac veins
Cardiocytes are joined at ends by ______
intercalated discs
Cardiac muscle component that resembles egg cartons
Interdigitating folds
Gap junctions: allow flow of electrical stimuli
Electrical junctions
Desmosomes provide mechanical adhesion for ____in cardiac muscle
Mechanical junctions
Triggered to contract by Ca2+ entering the sarcoplasm
Cardiac muscle tissue
Ca2+ entering the sarcoplasm of cardiac muscle tissue signals sarcoplasmic reticulum to release Ca2+ ions
Ions diffuse into sarcomeres
Trigger _____
sliding filament mechanism
In the conduction system, ____tie the cardiac muscle cells together physically, contain gap junctions that allow electrical signals to pass, therefore muscle impulses can therefore pass from one cell to the next instantly
Intercalated discs
Heart exhibits _____(heart itself, not external nerves initiates muscle impulses)
autorhythmicity
Specialized heart muscle cells initiate muscle impulses,
the rest of the muscle cells just pass along the impulse
These initiation cells make up the _____
conduction system
Electric muscle impulses travel throughout the cardiac muscle tissue by way of the _____
intercalated discs
Muscle impulses are initiated at the _____ in the posterior of the right atria (pacemaker).
Sinoatrial (SA) node
The impulse is carried to a node at the inferior border of the right atria called the ______
Atrioventricular (AV) node
The impulse is carried from the atrioventricular node down the ____
AV bundle (bundle of His)
The branches of the Bundle of His, called the ____, carry the impulse throughout the walls of the ventricles
Purkinje fibers
Heart rate is set by SA node but rate is altered by extrinsic and neural controls such as:
Visceral sensory fibers
Parasympathetic fibers
Branches of vagus nerve. Decrease heart rate
Restricted to SA node, AV node, coronary arteries
Parasympathetic fibers
Travel to heart from cervical and upper thoracic chain ganglia (Innervate SA node, AV node, coronary arteries and cardiac musculature throughout heart)
Increase heart rate and strength of contraction
Sympathetic nerves
____ is controlled by cardiac centers in reticular formation of medulla
Autonomic input
Cardiac centers in the retricular formation of the medulla. The ___ center influences parasympathetic neurons. The ___ center influences sympathetic neurons
Cardioinhibitory
Cardioacceleratory
