Week 5, Lecture 3 Flashcards
If you place a stethoscope at the 2nd right intercostal space at the sternal border, what cardiac structure are you likely listening to?
A. The aortic valve
B. The pulmonic valve
C. The tricuspid valve
D. The mitral valve
A. The aortic valve
What structure brings oxygenated blood to the embryonic heart?
A. The cardinal vein
B. The umbilical artery
C. The dorsal aorta
D. The umbilical vein
D. The umbilical vein
What is the papillary muscle attached to?
A. The chordae tendinae of a semilunar valve
B. The chordae tendinae of an atrioventricular valve
C. Both the left and right aspects of the interventricular septum
D. Both the left and right aspects of the interatrial septum
B. The chordae tendinae of an atrioventricular valve
what is the mediastinum
the middle of the thorax
Between the mediastinal pleura
Posterior to the sternum
Anterior to the vertebrae
Superior to the diaphragm
Separates the two lateral pleural cavities
subdivisions of the mediastinum
Superior
Inferior
* Anterior
* Middle
* Posterior
where is the heart located
The heart and pericardial sac are approximately 2/3rd to the left and 1/3rd to the right of the median plane (middle mediastinum).
4 spots on the heart to listen to
aortic valve
pulmonary valve
tricuspid valve
mitral valve
in order from top to bottom where to listen on heart
APTM
aortic (upper middle)
pulmonary (upper left)
tricuspid (bottom middle)
mitral (bottom left)
mitral valve
(apex): 5th intercostal space at the midclavicular line.
tricuspid valve
lower left sternal border in the 4th/5th intercostal space.
aortic valve
2nd right intercostal space near the right sternal border.
pulmonic valve
2nd left intercostal space near the left sternal border.
pericardium function
Fibrous membrane that encloses the heart and the roots of the great vessels.
Anchors and protects the heart
Prevents overfilling
Allows it to work in a friction-free environment
2 layers of the pericardium
Outer fibrous pericardium (tough, inelastic CT)
Inner serous pericardium.
* Parietal layer (inner surface of the pericardium)
* Visceral layer (lines outer surface of the heart= epicardium)
what are the 2 parts of the inner serous pericardium? which is inner most layer of pericardium/outer layer of heart (epicardium)
parietal and visceral layer
visceral layer is inner most layer
pericardiophrenic ligament; the fibrous pericardium (outer layer) is continuous with what
the central tendon of the diaphragm
3 walls of the heart chamber from superficial to deep
- endocardium
- myocardium
- epicardium (outer most layer of heart, inner most layer or pericardium)
3 layers of heart chamber
- Endocardium: a thin internal layer (endothelium and subendothelial connective tissue) or lining membrane of the heart that also covers its valves
- Myocardium: a thick, helical middle layer composed of cardiac muscle
- Epicardium: a thin external layer (mesothelium) formed by the visceral layer of serous pericardium
epicardium is? what’s it made of?
is the outermost layer of the heart wall, also called the visceral layer of the serous pericardium
The serous pericardium is composed mainly of mesothelium.
what’s in the subepicardial layer
loose CT contains the coronary vessels, nerves and ganglia, also an area of fat storage of the heart
what type of cells are in the myocardium (hint contractile cells and conducting cells)
cardiomyocytes
purkinje fibers
cardiomyocytes
are the individual muscle cells that make up the myocardium.
* Striated, uninuclear, often with one or two branches * Full of myofibrils and mitochondria
purkinje fibers
are specialized cardiac muscle fibers that play a crucial role in the conduction of electrical signals within the heart.
- Glycogen-filled, large diameter fibres, gap junctions, few myofibrils or mitochondria
different between cardiomyocytes and purkinje fibers
cardiomyocytes have lots of mitochondria and myofibrils (for contraction)
purjinke fibers have glycogen and gap junctions (for conduction/ impulse generation)
3 components of myocardium
papillary muscles
pectinate muscles
trabecular carneae
papillary muscle found where? connect by?
located in the ventricles of the heart.
Connected to the AV valves by chordae tendineae.
pectinate muscles are found where? and help do what?
muscular structures found in the walls of the atria, particularly in the right atrium.
Contribute to the contraction of the atria.
trabecular carneae is found where and does what
irregular, mesh-like ridges or muscular columns found on
the inner walls of the ventricles.
Structural support for ventricles & maintain integrity of myocardium
intercalated discs in myocardium have
desmosomes and gap junctions and fascia adherents
Desmosomes: hold cells together; prevent cells
from separating during contraction
Gap junctions: directly connect the cytoplasm of 2 cells – allow ions to pass from cell to cell; electrically couple adjacent cells
* Allows heart to be a functional syncytium, a single coordinated unit
Fascia adherens: anchors actin filaments, helps to transmit contractile forces
endocardium forms the
lining of the atria and ventricles
endocardium is made up of what type of cell and what tissue
Simple squamous epithelium (endothelium)
Underlying layer of fibroelastic connective tissue with
scattered fibroblasts
Deeper layer of subendothelial fibroelastic CT.
- Contains: small blood vessels & nerves, Purkinje fibers
endocardial cells are found where
specialized cells that make up
the endocardium.
Form the inner lining of the AV and semilunar valves, ensuring they open and close efficiently during the cardiac cycle.
cardiac muscle cells
- how many nuclei?
-connected by?
-how many mitochondria?
-made of?
striated, short, branched, fat, interconnected
– Uninuclear cells
* Nucleus is situated at the center of the cell body
– Cells connected at intercalated discs
* Many gap junctions populate the intercalated discs
– Contain numerous large mitochondria (25–35% of cell volume) that
afford resistance to fatigue
– Rest of volume composed of sarcomeres
* Z discs, A bands, and I bands all present
– T tubules and cisternae present
* Sarcoplasmic Reticulum is simpler than in skeletal muscle
* T-tubules are larger
what are cardiac muscle fibers anchored to the heart by
fibrous skeleton
fibrous skeleton of the heart
-how many rings
This is a complex framework of dense collagen/fibroblastic tissue forming four fibrous rings that surround the orifices of the valves, a right and left fibrous
trigone (formed by connections between rings), and the membranous parts of the interatrial and interventricular septa.
trigones of the fibrous skeleton do what
Keeps the orifices of the AV and semilunar valves patent and
prevents them from being overly distended
(keep valves open so dont collapse)
function of fibrous skeleton
Provides attachments for the leaflets and cusps of the valves.
Provides attachment (origin and insertion) for the myocardium.
Forms an electrical “insulator” by separating the impulses of the atria and ventricles and by surrounding and providing passage for the initial part of the AV bundle of the conducting system of the heart.
CHART ON SLIDE 29
right side vs left side of myocardial walls
right side: More trabeculated, less muscle mass, thinner
left side: Less trabeculated, more muscle mass, thicker
left side vs right side AV valves
right: Tricuspid (3 leaflets, 3 sets of papillary muscles: anterior, posterior, septal)
left: Mitral/ Bicuspid (2 leaflets, 2 sets of papillary muscles: anterior and posterior)
conduction system on right side (none on left side)
where are the nodes found
SA node and AV nodes are in the right atrium
interatrail septum
Separates the right and left atria
Note: Fossa Ovalis
inter ventricular septum
Separates the right and left ventricles
Inferior: Large, muscular
Superior: Small,
membranous
Corresponds to the anterior and posterior IV sulcus.
auricles
Increase the capacity of the atrium and the volume of blood can be contained.
SA node is the what of the heart
pacemaker