Term
| Cardiovascular System Function: |
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Definition
*Perfusion
- provides oxygen to the tissues, transport nutrients and hormones and remove waste from tissues
*Temperature Regulation |
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| oxygenated blood moves through the arteries to small arteries (arterioles) to capillaries where exchange of gases occurs in the tissues |
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carry blood away from heart, in high pressure tubes.
* thick walled, elastic and deeper in the body |
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carry blood back to the heart, in low pressure tubes
* thinner walled, some more superficial |
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| exchange of gases, nutrients and waste products, precapillary sphincters contain smooth muscle |
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| heart is relaxing, heart fills, coronary arteries fill |
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| some veins have one-way valves to prevent backflow |
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| outer fibrous layer, middle layer of smooth muscle, elastic tissue and smooth inner lining of endothelium |
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single layer of squamous endothelium
- allows exchange of gases, nutrient and waste products, varying permeability |
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| Capillaries used by Sympathetic Nervous System |
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Definition
| vasoconstriction and vasodilation |
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| How the body vasoconstricts: |
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Definition
*Sympathetic stimulation
-a1 receptors on precapillary arterioles
-stimulation causes peripheral vasoconstriction, shunts blood away to the fight or flight tissues |
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| On the other side of the capillaries |
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Definition
| Blood enters venules -> veins -> back to heart |
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| Leakage occurs out of the capillaries |
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Definition
*fluid component of blood leaks into interstitial fluid=lymph
*drains into lymphatic vessels->lymph nodes->thoracic duct->back into the blood |
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| Where is the heart located? |
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Definition
*situated in the mediastinum- space between the two pleural cavities that contain the lungs.
*space between the lungs |
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| Mediastinum also contains: |
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Definition
| Esophagus, Trachea, Vessels (aorta, vena cava), and mediastinal lymph node |
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| heart sac, connective tissue, tough fibrous outer layer, loosely attached to diaphragm, 2 inner layers with lubricant between |
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| heart muscle, made of cardiac muscle and chambers lined with endocardium |
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| The chambers of the heart: |
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Definition
* 2 atria - receive blood and help fill ventricles
* 2 ventricles - pump blood to lungs (right) and to body (left) |
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Definition
| separate the heart into right and left sides |
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Definition
| A-V valves and semilunar valves, all are one-way valves, which prevent backflow (ensures one-way flow of blood) |
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Definition
Atrioventricular valves - located between atrium and ventricle
- ensures one-way flow from atrium to ventricle
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| cord-like extensions from valve flaps, they attach to inner heart wall (to papillary muscles) to hold the valve close |
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Definition
located between ventricles and the arteries exiting the heart
*aorta - left
*pulmonary artery - right
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| What do semilunar valves do? |
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Definition
| prevent backflow of blood from artery back into ventricle |
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- all have 3 cusps except left A-V (mitral/bicuspid)
- between left atrium and left ventricle |
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Definition
| - between right atrium and right ventricle |
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| -between the left ventricle and aorta |
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| Right semilunar: pulmonary/pulmonic |
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Definition
| - between right ventricle and pulmonary artery |
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| Blood draining from the body: |
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Definition
| Unoxygenated, returning from systemic circulation, goes to right atrium thru vena cava |
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Definition
drains cranial body
* head, neck, forelegs |
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Definition
- drains caudal body
*abdomen, rear legs |
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Definition
| blood passes from right atrium thru open tricuspid valve to the right ventricle |
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Definition
| when ventricle contracts (systole) tricuspid valve closes, blood passes from the right ventricle through pulmonary valve to pulmonary artery |
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Definition
| To keep blood from leaking back from Pulmonary Artery into the ventricle |
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Definition
| only depends on pressure in the vessel to close it , same with all valves |
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| divides into right and left pulmonary arteries to supply both sides of lungs, carries unoxygenated blood to the lungs |
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| In the lungs arteries continue to divide and ... |
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Definition
get smaller -> arterioles -> capillaries
- very thin walled and they surround alveoli |
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Definition
| from lungs goes through pulmonary vein to the left atrium |
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Definition
blood passes from left atrium through open mitral valve to the left ventricle.
-passive ventricular filling followed by atrial contraction |
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| When the Left Ventricle Contracts |
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Definition
| mitral valve closes, blood passes from left ventricle through open aortic valve into aorta |
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Definition
| aorta subdivides and supplies the entire body with oxygenated blood |
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Definition
| vena cavae ->right atrium -> tricuspid valve -> right ventricle -> pulmonic valve -> pulmonary arteries -> lungs ->pulmonary veins -> left atrium -> mitral valve -> left ventricle -> aortic valve and then aorta |
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Definition
| they supply the myocardium itself with oxygenated blood, can only fill between beats |
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Definition
| drain deoxygenated blood from capillary beds of the myocardium -> into right atrium |
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Definition
| Action potential comes down neuron-> neuromuscular junction->Ach into synapse->causes Action potential on muscle cell ->T-tubules-> calcium release -> muscle contraction |
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| Resting Membrane Potential |
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Definition
| "resting" phase :Na+ outside, K+ inside cell. Inside of cell is negative |
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Definition
| Na+ channels open, Na+ rushes in. Inside of cell becomes more positive |
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Definition
| Na+ channels close, K+ channels open, K+ rushes out, leave cell more negative. |
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Definition
| Restores ions to the proper side of the membrane, reestablishing membrane potential. (charging the battery) |
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| Heart muscles have action potentials too but... |
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Definition
| don't rely on a nerve to start it like skeletal muscle does |
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Definition
| Na+ slowly leaks in -> cells slowly becomes more positive until it reaches threshold and depolarizes |
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| Ca2+ from sarcoplasmic reticulum moves into cell cytoplasm |
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| Actively pumped back into sarcoplasmic reticulum, requires ATP |
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| Cardiac cells are connected via intercalated discs, has gap junction |
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Definition
| ions pass from cell to adjacent cell, causes a wave of depolarization to pass from cell to cell to cell... |
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Definition
| allows heart to depolarize in correct order, if it doesn't happen : fibrillation |
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Definition
| sinoatrial node depolarizes-> depolarization spreads through atria -> atrial contraction |
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Definition
| Impulse moves on to the AV node, where it pauses |
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| When the impulse moves on to the AV node and pauses it gives... |
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Definition
| the atria a chance to contract and fully fill the ventricles prior to ventricular depolarization |
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Definition
| where is meets muscle -> calcium release -> contraction will follow |
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Term
| What do Purkinje Fibers do? |
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Definition
| allows the blood to be pushed from the apex of the heart up to the great vessels |
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Term
| Absolute Refractory Period |
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Definition
| Period when no matter how strong the stimulus, the cell can't depolarize again, sodium channels are already open so there is no resting potential. |
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| Relative Refractory Period |
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Definition
| period when cell may be depolarize again if there is a strong enough stimulus |
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| Refractory periods are essential to... |
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Definition
| maintain proper sequence of depolarizations so that the heart will be effective as a pump |
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| If an area depolarizes out of sequence... |
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Definition
| much of the time, would not spread through myocardium due to cells being in their refractory periods |
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Definition
| sometimes spreads -> depolarizations out of order -> ineffective contractions |
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| What causes an Ectopic Focus? |
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Definition
| Some damage to cells has made them abnormally leaky to sodium -> reach threshold -> depolarize |
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Term
What if the Sinoatrial (SA) Node is late?
or for some reason the AP doesn't get through? |
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Definition
| All cardiac cells are leaky, escape beats |
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Term
Cardiac Muscle Contraction:
Systole |
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Definition
| As AP reaches individual cardiac muscle cells -> release of calcium -> actin and myosin bind -> contraction occurs |
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Term
Cardiac Muscle Contraction :
Diastole |
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Definition
| Calcium pumped back into Sinoatrial Node -> relaxation of muscle |
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Definition
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Definition
| closure of the AV valves at the beginning of ventricular systole |
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Definition
| closure of the semilunar valves at the beginning of ventricular diastole |
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Definition
| normally blood flow thru heart is silent, they are caused by turbulence in blood, usually as it flows thru valves |
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Definition
- damaged valve, lets blood go the wrong way and won't let blood thru easily
- thin blood (anemia) |
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Definition
| heart rate X stroke volume |
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Definition
| volume pumped with each stroke (systole) |
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| So the heart depolarizes all on its own due to... |
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Definition
- to permeability to sodium
-to intercalated discs/gap junctions
-But can be influenced by ANS |
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Definition
| provides neural and hormonal stimuli which speed or slow the heart from its normal automatic rate |
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| Sympathetic Nervous System |
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Definition
Speeds the heart through hormones
- epinephrine
-norepinephrine |
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Definition
| heart spends a grater proportion of the cycle in systole, less in diastole |
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| Why is tachycardia so dangerous? |
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Definition
| not only the heart working harder but the heart can't feed itself as well |
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| Parasympathetic Nervous System |
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Definition
| Slows the heart via neural influence |
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Definition
| detects action potentials as they pass thru the myocardium by P-wave, QRS complex and T-wave |
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Definition
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Definition
| ventricular depolarization |
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Definition
| ventricular repolarization |
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| What does a Electrocardiograph help determine? |
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Definition
- heart rate and rhythm, arrhythmias
- abnormal size of heart chambers
- abnormal electrical conduction |
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Definition
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| VPC / Ventricular premature complex |
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Definition
| abnormal electrical activity in the heart due to signal coming from an ectopic focus |
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| what is VPC also know as .. |
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Definition
| PVC / Premature ventricular contraction |
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Definition
| someone is leakier than the SA node, often an area of damaged myocardial cells -> leaks -> depolarization out of sequence |
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| Heart Block is also known as |
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Definition
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| Electrical impulse is being delayed more than normal at the AV node |
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| ECG just documents electrical activity of the heart not |
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Definition
| necessarily muscular contraction |
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| Electromechanical Dissociation |
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Definition
| what happens if the impulse does not pass from the conduction pathway into the muscle fibers themselves |
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| When does electromechanical dissociation happen? |
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Definition
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| Largest artery, leaves left ventricle and arches over heart |
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| come off before aorta leaves heart - supply myocardium |
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| What are the parts of the Thoracic Aorta? |
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Definition
| coronary arteries, brachiocephalic artery and subclavian arteries |
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| subclavian arteries supply? |
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Definition
| the blood for the head and front limbs |
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| Brachiocephalic Artery supplies |
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Definition
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| gives rise to carotid arteries - left and right, deep to jugular veins |
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| What does the Abdominal Aorta include? |
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Definition
| celiac artery, mesenteric artery, renal arteries, internal and external iliac arteries |
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| Celiac Artery branches into |
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Definition
- gastric artery
-splenic artery
- hepatic artery |
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| double fold of peritoneum supporting intestines |
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| supply kidneys themselves, also present large volume of blood to kidneys for filtration and purification |
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| Internal and External iliac arteries supply |
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Definition
| pelvis, hips, rear limbs and genitalia |
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Definition
run along with and have the same names as arteries (ie : renal veins)
-except for jugular veins, venae cavae (cranial and caudal) and portal vein and portal circulation |
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Definition
| drains head, neck, front limbs. thorax and empties into right atrium |
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| there are left and right, internal and external, drain head and neck then empty into cranial vena cava |
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| drains abdomen, caudal to body, empties into right atrium |
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| Portal Vein and Portal Circulation |
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Definition
| vein draining the stomach, spleen, intestines, pancreas come together to form the hepatic portal vein |
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Definition
| flow through an organ (a second capillary bed) on their way back to heart |
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| goes through the liver so the liver can rid the blood coming from the GI tract of toxins, excess glucose etc.. before that blood makes it to the rest of the body (systemic circulation) |
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| So how does the liver get oxygenated blood? |
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Definition
- hepatic artery branches off aorta
- dual blood supply *hepatic artery and hepatic portal vein
-blood leaves the liver via the hepatic vein -> vena cava ->heart |
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| is fetal tissue in contact with maternal uterus, where gas, nutrient and waste exchange takes place |
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Definition
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| is a bypass for blood through the fetal liver, since the fetal liver is mostly nonfunctional |
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| so the blood flows from the umbilical vein through the liver to |
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Definition
| caudal vena cava to right atrium |
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| Right atrium- a fetal blood has 3 paths it can follow |
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Definition
-normal adult pattern
- thru ductus arteriosus
-thru foramen ovale |
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Definition
| *right atrium -> right ventricle -> pulmonary artery -> lung ->pulmonary vein -> left atrium ->left ventricle -> aorta |
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Definition
| is a hole in the septum between the left and right atria, bypasses right ventricle and the lungs |
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Definition
Blood that doesn't go thru foramen ovale -> right atrium -> right ventricle
-> pulmonary artery -> ductus arteriosus -> aorta |
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| The purpose of Ductus Arteriosus |
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Definition
| bypass fetal lungs and liver, because they are nonfunctional. |
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| Persistence beyond birth is bad because... |
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Definition
is pathological
- patent foramen ovale
-patent ductus arteriosus
-patent ductus venosus |
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Term
Patent Ductus Arteriosus
aka: PDA |
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Definition
| bypass from pulmonary artery to aorta, blood bypasses lungs... muy mal! |
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| What sound does a Patent Ductus Arteriosus make and can it be repaired? |
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Definition
| "Machinery murmur" can be surgically repaired (ligated) |
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Definition
umbilical vein -> ductus venosus through liver -> caudal vena cava
- bypasses liver |
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