Cardiovascular Heart Flashcards
Components of Cardiac Muscle Cell?
*Has similar cell components as skeletal muscle cell (T tubule, sarcomeres, sarcoplasmic reticulum, etc.)
*1 nucleus
*Branched
Cardiac Muscle
*Some of the muscle cells are adapted to conduct an impulse instead of
contracting
Components of Intercalated Disc?
The intercalated discs are made of
* Gap junctions: allow for quick communication between cells for a coordinated contraction
* Fascia adherens: desmosome-like connections;
tension is distributed between cells
Components of the Cardiovascular System?
*Heart
- Pumps blood
*Arteries
- Carry blood awayfrom heart
*Veins
- Carries blood towardheart
*Blood
- Transports nutrients, wastes, etc.
What is the Pulmonary Circuit?
*Route between heart and lungs
*Allows blood to pick up oxygen
*Right ventricle →pulmonary
trunk→pulmonary arteries →
lungs →pulmonary veins →left
atrium
What is the Pulmonary Circuit?
*Route between heart and lungs
*Allows blood to pick up oxygen
*Right ventricle →pulmonary
trunk→pulmonary arteries →
lungs →pulmonary veins →left
atrium
What is the Systemic Circuit?
*Route between heart and body
tissues (other than lungs)
*Brings oxygen to cells
*Left ventricle →Aorta →Cells of
body →Veins →Right atrium
What are the basic components of the heart?
*Heart pumps ~1800 gallons/day through 60,000 miles of blood vessels
*Approximately fist-sized
*Sits to the left of midline, on top of diaphragm
*4 distinct chambers
What is the Pericardium?
The pericardium is a triple-layered sac that
encloses the heart
* Outer layer = fibrous pericardium
* Inner layers = serous pericardium
The tough, fibrous pericardium
* Anchors heart
* Prevents overfilling
* Dense irregular CT
What are the components of Pericardium?
The serous pericardium (deep to fibrous pericardium), is made of
* Visceral pericardium
* Pericardial cavity with pericardial fluid
- Fluid reduces friction between contracting heart and outer wall of pericardial sac
* Parietal pericardium
What is Cardiac Tamponade?
Cardiac Tamponade
* Occurs when there is excess pericardial fluid
- Also called a pericardial effusion
What are the Layers of Pericardium and Heart Wall?
*Epicardium
- = visceral pericardium
*Myocardium
- Cardiac muscle tissue
*Endocardium
- Simple squamous
Parts of the heart?
https://surgmedia.com/anatomy-of-the-human-heart/
What are the Ventricle Features of the heart?
Papillary muscles (both ventricles)
* Nipple-shaped projections of cardiac muscle
* Are attached to atrioventricular valves via chordae tendineae
- “heart strings”
- Dense regular CT
The left ventricular myocardium is thicker than right’s
* Strong to pump blood to whole body
What are the Heart Valves: Atrioventricular?
The atrioventricular (AV) valves are located
between atria and ventricles
* Tricuspid (right)
* Bicuspid (left)
- Also called mitral valve
* Cusps are formed by endocardium and reinforced with dense CT
Are designed to keep blood flowing one direction
(atria →ventricles)
* Chordae tendineae (and papillary muscles) prevent valves from inverting into atria with ventricular contractions
What are the Heart Valves: Semilunar?
The semilunar valves keep blood moving
one direction
* Prevent blood from flowing backwards
towards ventricles
* When ventricles relax, blood fills cusps, forcing
valves to close
Pulmonary semilunar
* Between right ventricle and pulmonary trunk
Aortic semilunar (partially shown in top
image)
* Between left ventricle and aorta
What happens when semilunar valves open?
As ventricles contract and intraventricular pressure rises blood is pushed up against semilunar valves, forcing them open.
What happens when semilunar valves close?
As ventricles relax and intraventricular pressure falls, blood flows back from arteries filing the cusps of semilunar valves and forcing them to close.
What are Heart Sounds?
*“Lub dub”
*Sounds are due to closing of heart
valves
- Lub = closing of AV valves
- Dub = closing of semilunar valves
What is a Heart Murmur?
With a murmur, a sound (“Whooshing” or clicking) can be heard as blood flows backward into chamber
* Due to an incompetent valve
* Mitral valve prolapse
- Most common, weakness in collagen of valve or chordae tendineae
*Stenosis
- Narrowed opening between valves
- May be caused by calcium deposits or illness
What are the characteristics of Cardiac Muscle Cells?
Cardiac muscle cell characteristics:
* Striated
* Branched
* Most are uninucleate
* Intercalated discs (= “inserted between”) are between cells
Some cells contract, others conduct
electrical impulse through heart
(more later)
What is the fibrous skeleton?
- Fibrous skeleton →barrier between atria and ventricles that prevents an electrical impulse from passing
- Only ONE pathway from atria to ventricles →AV NODE
What is the Cardiac Conduction System?
- Cardiac muscle cells have autorhythmicity
- Do not depend on extrinsic stimulation
*Nodes and bundles in cardiac muscle conduct electrical impulses through heart - = Cardiac conduction system
What is the pathway for the Cardiac Conduction System?
Pathway:
* Sinoatrial (SA) node (pacemaker)
- In right atrium
- Initiates electrical impulse; inherent rhythmicity
- Stimulates atria and via internodal pathway, stimulates atrioventricular (AV) node
* Atrioventricular (AV) node
- Delays impulse , then stimulates
* Atrioventricular (AV) bundle, then
* Right and left bundle branches, then
* Purkinje fibers
What is the contraction of the Cardiac Conduction System?
*Atria contract top to bottom
(simultaneously)
*Ventricles contract bottom to top
(simultaneously)
What is the cardiac cycle?
- Cardiac Cycle = 1 cycle of contraction/relaxation of heart (1 heartbeat)
- Systole = contraction (forcing blood out)
- Diastole = relaxation (filling w/ blood)
What is the blood supply to the heart?
*Heart needs and external blood supply
(branches off of ascending aorta)
- Right coronary artery and branches
- Left coronary artery and branches
* Cardiac veins
- Drain blood to coronary sinus →empties into right atrium
What is Atherosclerosis?
- Buildup of plaque in arteries
- Cause narrowing, making blood flow more difficult
*It is the most common cause of arteriosclerosis (= hardening of the
arteries)
*Causes - Damage to inner surface (endothelium)
– Caused by inflammatory response due to smoking, diabetes, high blood pressure, etc. - Cholesterol, calcium, and lipids attach to damaged lining and harden into
plaques
What happens in a Myocardial Infarction = Heart Attack?
- Result of blood not reaching cardiac muscle tissue
- Can be caused by a Thrombus →stationary blood clot
- Results in Ischemia →restriction in blood supply resulting in oxygen and glucose deprivation of tissues
