Module 13- Heart
Brachiocephalic trunk branches
- Right common carotid artery: ascends to supply right side of head, neck and brain - Right subclavian artery: travels laterally to deep clavicle to supply right upper extremity
When the ventricles are in systole, the atria are in diastole
- The AV valves will be closed - The semilunar valves will be opened to allow blood to flow into the aorta and pulmonary trunk
Both atria and ventricles undergo systole and diastole
- The AV valves will be opened to allow blood to flow from the atria into the ventricles - Semilunar valves are closed to prevent blood in aorta and pulmonary trunk from flowing backwards
Gap junctions and intercalated discs of myocytes
- allow signal to propagate easily and quickly from cell to cell, so myocytes contract synchronously
Aortic semilunar valve
- at the base of aorta o Prevents backflow from the aorta o Composed of three flaps o When ventricle relaxes, the blood flowing backwards from the aorta will fill the cusps of the valve causing it to close
Left atrioventricular (mitral or bicuspid) valve
- between the left atrium and left ventricle o Has two cusps, compared to three cusps on the tricuspid valve o Two cusps are attached by chordae tendineae to two papillary muscles
Superior vena cava
- drains blood from regions superior to the diaphragm - Head, neck, upper limbs and thoracic region
what two structures on the heart close after birth and why
- ductus arterioles and foramen ovale - both close as a change of pressure due to the air from the lungs - closing ensures blood travels to lung for oxygenation
Aorta
- largest artery in body and arises from left ventricle
The muscle of the left ventricle is
- much thicker and better developed than the right - In order to pump blood to systemic circuit, the left ventricle must generate a great amount of pressure
Aortic arch
- runs inferiorly and becomes the descending aorta
Right AV valve is attached to
- strong strands of connective tissue called the chorea tendineae - They connect each of the flaps to a papillary muscle and create tension - This prevents backflow of blood into the atria
Auricle
- superficial extension of the atria near the superior surface of the heart
fibrous pericardium
- tough, outer layer made of dense connective - prevents heart from over expanding and over filling - protects the heart and maintains its position in the thorax
endocardium
-inner layer of epithelium - simple squamous epithelium - lines the internal surface of heart chambers and external surface of heart valves
Inferior vena cava
-travels alongside descending aorta and drains blood from areas inferior to the diaphragm -§ Lower limbs and abdominopelvic region of the body
lub
AV valves closing
veins
Carry deoxygenated blood from the heart wall muscle to the right atrium
heart sounds
Lub-dub sound of heart beat is the sound of valves closing
autonomic innervation affect on heart rate
does not initiate a heartbeat but can increase/decrease heart rate
parasympathetic innervation of HR
during rest lowers heart rate no influence on heart muscle (strength of contraction) o Being at vagus nerve (X) and travel to cardiac plexus near base of heart o Fibers travel to SA and AV node and cause heart rate to decrease
cardiomegaly
abnormal enlargement of the heart due to heart disease, high blood pressure, heart failure
superior border of heart
aorta and superior vena cava
pressure highest to lowest
aorta, arteries, arterioles, capillaries, venules, veins, venae cava blood pressure drops as you move farther from heart
what happens on day 20 of cardiovascular development
endothelial tubes begin to fuse
heart wall structure
epicardium (outer layer) myocardium endocardium
In the pulmonary circuit, __________.
arteries carry deoxygenated blood to the lungs
pericardial effusion
excess fluid within the pericardial cavity takes up space and limits how much blood the heart can take in
cardiovascular system
first major organ to become functional
blood pressure
force of blood pushing against the inside walls of blood vessels changes with each stage of heart beat blood pressure is essential to circulate throughout body
The right ventricle ________.
has thinner muscular walls than does the left ventricle
LVAD
artificial left ventricle patients with heart failure need to use this
what happens on day 35 of cardiovascular development
bending is complete heart has ductus arterioles and foramen ovale
Pulmonary semilunar valve
between right ventricle and base of pulmonary trunk o Has three small flaps of endothelium reinforced with connective tissue o When ventricle relaxes, the pressure difference causes the pulmonary semilunar valve to close o No papillary muscles or chorea tendineae associated
Right atrioventricular (tricuspid) valve
between the right atrium and right ventricle o Has three flaps made of endocardium reinforced with connective tissue o Flaps are connected by chordae tendineae to the papillary muscles, which control the opening and closing of the valves
Interventricular septum
between the ventricles, thicker than the interatrial septum because ventricles generate more pressure when they contract
parietal pericardium
between visceral and fibrous layers
foramen ovale
blood goes from right atrium-->left atrium--> systemic circulation turns into the fossa ovalis is an adult
Heart autorhythmicity
capable of initiating its own heartbeat independent of external nerves
pericardial effusion and constrictive pericarditis both cause
cardiac tamponade (rapid heart beat and low blood pressure)
Pulmonary trunk, arteries and their branches are the only arteries that
carry deoxygenated blood (carry blood the lungs)
descending aorta branches
celiac trunk superior mesenteric artery right and left renal artery right and left gonadal artery inferior mesenteric
Papillary muscles
connect to the chord tendinae and contract to help prevent AV valves from prolapsing
all of the veins drain into
coronary sinus which runs in poster part of coronary sulcus and empties into right atrium
what happens on day 24 of cardiovascular development
heart continues to bend and elongate
what happens on day 22 of cardiovascular development
heart starts pumping
sympathetic innervation of HR
increase heart rate and causes hart muscle to increase strength of contraction o Begin at T1-T5 levels and flow to cardiac plexus near base of heart o Fibers travel to the SA and AV node and cause heart rate to increase
serous pericardium
inner layer formed by 2 continuous layers (visceral and parietal pericardium)
Circumflex artery supplies
left atrium and ventricle
Which chamber of the heart can generate the greatest pressure because it can contract with the most strength?
left ventricle
what is the purpose of the delay in the conducting system
makes sure atria contracts before the ventricles
male and female gonadal arteries
male= testicular artery female= ovarian artery
myocardium
middle layer of the heart thickest layer made of cardiac muscle contraction of the myocardium pumps blood through the heart into the major arteries
Ascending aorta
moves superior direction and then reverses direction forming aortic arch
Purkinje fibers
myocardial conductive fibers that spread the impulse to the myocardial contractile cells in the ventricles
Heart formation
o Heart begins as two separate tubes that fuse to form a single tube o Primitive heart tube elongates and begins to fold o Forms an S shape which places chambers and vessels into alignment
visceral pericardium
on surface of heart (touching organ) It forms part of the heart wall, called the epicardium
epicardium
outer visceral layer of serous pericardium
the SA node is the
pacemaker of the heart
Pectinate muscles
parallel muscular ridges in the right atrium
apex
pointy part of heart left of midline
posterior inter ventricular artery supplies
posterior surface of left and right ventricles
systole
pressure against walls of arteries when ventricles contract period of contraction that the heart undergoes while it pumps blood into circulation
Right coronary artery
proceeds along coronary sulcus and supplies blood to right atrium, both ventricles and heart conduction system
Trabeculae carneae
ridges of cardiac muscle covered by endocardium located in the walls of ventricles
ascending aorta branches
right and left coronary arteries
coronary circulation
right and left coronary arteries - travel within the coronary sulcus - supply the heart wall muscle with oxygen and nutrients - only branches off the ascending aorta
aortic arch branches
right and left subclavian right and left common carotid
A blockage in the pulmonary trunk would cause a back-up of blood and limit blood from leaving which chamber of the heart?
right ventricle
inferior border of heart
right ventricle
middle cardiac vein
runs with posterior interventricular artery
dub
semilunar valves closing
Superior mesenteric artery
single artery that supplies blood to midgut organs
position of the heart
slightly left of midline, deep to the sternum
pericardial cavity
space between visceral and parietal pericardium has pericardial fluid that prevents fiction
to decrease strength of heart beat
stop sending sympathetic innervation it will NOT decrease due to parasympathetic innervation but lack of sympathetic
Anterior interventricular artery supplies
supplies anterior surface of both ventricles and inter ventricular septum
Left coronary artery
supplies blood the left side of heart, left atrium and ventricle and interventricular septum
right marginal artery supplies
supplies the right border of the heart
Blood that is transported to and from all of the tissues of the body (with the EXCEPTION of the lungs) is in the ________.
systemic circuit
constrictive pericarditis
thickening/fibrosis of the parietal pericardium restricts heart so it can't fill as much
What is the purpose of the chordae tendineae?
to keep the atrioventricular valves from prolapsing, preventing regurgitation of blood back into the atria
Both of the ventricles are lined with
trabeculae carineae, ridges of cardiac muscle covered by endocardium
Systemic circulation
transport oxygenated blood to all the tissues of the body and returns deoxygenated blood and carbon dioxide to the heart to be sent back to pulmonary circulation
Pulmonary circulation
transports blood to and from the lungs, where it picks up oxygen and delivers carbon dioxide for exhalation
small cardiac vein
travels close to the marginal artery
great cardiac vein
travels with the anterior interventricular artery
left coronary artery branches into
1. Anterior interventricular artery 2. Circumflex artery
conducting system of heart
1. SA node generates impulses 2. impulses pause (delay) at the AV node 3. AV bundle connects atria to the ventricles 4. bundle branches conduct impulses through interventricular septum 5. conducting network stimulates contractile cells of both ventricles
the cardiac cycle
1. atria systole: atria contracting and blood flow to relaxes ventricles, AV valves open, semilunar valves closed 2. ventricles systole: ventricles contract, AV valves closed, semilunar valves open as blood goes into pulmonary trunk and aorta 3. atrial diastole 4. ventricular diastole
order of blood flow
1. inferior and superior vena cava 2. right atrium 3. right AV valve (tricuspid) 4. right ventricle 5. pulmonary semilunar valve 6. pulmonary trunk 7. pulmonary arteries 8. lungs for oxygenation 9. pulmonary veins 10. left atrium 11. left AV valve (bicuspid) 12. left ventricle 13. aortic semilunar valve 14. aorta 15. systemic circuit (body tissues
right coronary arteries branches into
1. right marginal artery 2. posterior inter ventricular artery
pericardium
Double-layered membrane surrounding the heart **the heart is surrounded but the pericardium, but not in it**
ductus arteriosus
Ensures that only a small volume of oxygenated blood passes through pulmonary circuit becomes ligaments arteriosum in an adult
Inferior mesenteric artery
Inferior mesenteric artery: superior to the common iliac arteries and supplies blood to hindgut organs
heart rate is set by
SA node at 70-80 bpm
diastole
ventricular relaxation, blood pressure lower occurs as chambers fill with blood
Interatrial septum
wall of heart muscle tissue between the right and left atria, contains the fossa ovalis
hypertrophic cardiomyopathy
walls of left ventricle and inter ventricular septum are abnormally thick consequences 1. lumen of left ventricle reduced 2. increased pressure in let atrium because less blood would be able to flow into left ventricle