Module 13- Heart

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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


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