Week Two: Cardiovascular System Flashcards
What is the pericardium?
Outer layer of the heart
Protects the heart
Loosely attaches the heart to the diaphragm (at base of the heart)
When is there positive and negative pressure on the heart?
Positive: exhaling
Negative: inhaling
What are the layers of the inner serous pericardium?
Parietal and visceral
What is the parietal layer of the pericardium?
Directly adjacent to fibrous pericardium (on the outside)
What is the visceral layer of the pericardium?
Deep to fibrous pericardium, also known as epicardium
Directly on the heart
What is the myocardium?
Thickest layer of heart tissue, located inside the sac formed by the pericardium
What is the endocardium?
Membranous lining between myocardium and chambers of the heart, lines vessels and chamber
What do veins do?
Collect deoxygenated blood from the tissues and RETURNS blood to the heart
Where does the vena cavea empty to?
Right atrium
Blood passes through the ___________ into right ventricle of the heart
Right atrioventricular valve (tricuspid valve)
During _______, right ventricle constricts and tricuspid valve closes
Systole
Blood is ejected from the right ventricle through the _______ into the pulmonary arteries
Pulmonary valve
What do arteries do?
Take oxygenated blood AWAY from the heart
What is systole?
Contraction of heart chamber
The right side of the heart is always what? (Oxygenated or deoxygenated)
Deoxygenated
The left side of the heart is always what?
Oxygenated or deoxygenated
Oxygenated
From the pulmonary arteries, blood passes through branching vessels to the pulmonary capillaries of the alveoli, where __________ takes place
Oxygen exchange
Where do pulmonary veins take blood to?
Is the blood oxygenated or deoxygenated
Left atrium
Oxygenated
Where does the blood flow after it goes from the left atrium through left atrioventricular valve (mitral valve)
Left ventricle
During systole,mitral valve ________, left ventricle ______, and blood enters ______ and aorta through aortic valve
snaps shut, contracts, coronary arteries
Describe what happens when blood travels through arterial branches (from aorta) to tissue capillaries
Oxygen and nutrient exchange occur, deoxygenated blood travels back to the heart
What are auricles?
Largest and most visible parts of the atria (these are little sacs on side of heart)
What is the left ventricle?
Long and narrow, thick walled, terminates at apex of heart (thickest muscle of heart)
What is an apex?
Pointy/ most ventral part of heart
What is the right ventricle?
Broader surface area; wraps around left ventricle (more flabby to touch)
What are the borders of ventricles separated by?
Interventricular sulci
What does the interventricular sulci contain?
Fat and blood vessels that are part of the coronary circulation of the heart
Where do the cranial and caudal vena cavae join?
Coronary sinus (common vena cavae or coronary junction), this collects blood from coronary circulation
What is the pulmonary trunk?
Where the pulmonary artery emerges from the right ventricle
Quickly divides into left and right pulmonary arteries traveling to each lung
(larger than the vena cavae)
What is the largest artery in the body?
Aorta
The walls of the aorta are the _______ of any blood vessel
Thickest
What is the aortic arch?
Where the aorta emerges from the left ventricle
What is the atrioventricular valve (tricuspid valve)
- Has three flaps
- Flaps originate from fibrous ring of the valve
- Increased blood pressure in the atrium during contraction forces flap to open
- One way valve
Where does the chordae tendinae connect to?
Papillary muscles
Where do papillary muscles attach to?
Interventricular septum (separates right and left ventricles)
What is the moderator band?
Tissue present in the right ventricle; originates at interventricular septum
- Not attached to flaps of tricuspid valve
- Provides additional structural support to the wall of the right ventricle
Explain the left atrioventricular valve(mitral valve) (bicuspid valve)
- Has two flaps
- Outer edges of flaps attached to the fibrous ring, inner edges attached to papillary muscles by chordae tendinae
- No moderator band in left ventricle
What are the semilunar valves?
Aortic and pulmonic valves, three flaps attached at their outer edges to a fibrous ring
What is a systole?
Heart muscle contracts, blood is ejected from the atria to the ventricles then from the ventricles to the arteries
(Peak blood pressure)
What is diastole?
Heart relaxes and refills with blood to be ejected during the next systolic contraction
(Lowest blood pressure)
What is the sinoatrial node? (SA node)
Natural pace maker (makes heart beat), occurs in right atrium
What is depolarization?
Process of generating electrical impulse from the SA node
Results from movement of cations (Na, K, Ca) into SA node cells
Systole
What is polarization?
Cations are pumped out of the cell
Results in the outside of the cell having a more positive charge than the inside of the cell
Diastole
What does an ECG/EKG do?
Measures waves of electrical activity
What are the Bundle of His?
Fibers in the ventricles
Electrical impulses travel down the interventricular septum to the bottom of the ventricles
What do purkinje fibers do?
Carry impulses from the Bundle of His up into the ventricular myocardium
Atria begin diastole while the ventricles are still….
Contracting
The fetus receives oxygen from the mother through the what?
Placenta
What is the foramen ovale?
Blocks blood flow from lungs, connects both atriums
Most of the blood from the right atrium flows directly into the left atrium through this
What is the ductus arteriousus?
Blood from the pulmonary artery flows into the lungs or through this directly into the aorta, but bypasses the lungs
What is “lub”
S1
- Closure of the mitral and tricuspid valves (AV valves) at the beginning of ventricular systole
- Mitral valve is loudest on the left side of the chest
- Tricuspid valve is best heard on the right
What is “dub”
S2
- Closure of the semilunar valves at the beginning of ventricular diastole
- Easiest to hear on the left side of the chest
What is different about large animals heart beats?
Sometime have S3 (rapid ventricular filling) and S4 (contraction of the atria)
Sounds like lub-dub-dub or lub-da-dub (gallop rhythm)
What is the cardiac output?
Amount of blood that leaves the heart
Depends on stroke volume and heart rate
What is the stroke volume?
Amount of blood ejected with each cardiac contraction
What is heart rate?
Frequency of heart contractions
What is the equation for cardiac output?
CO (Cardiac Output)=SV (Stroke Volume)X HR (Heart rate)
What increases cardiac output?
Vigorous exercise results in increased contractility, increased stroke volume, and increased heart rate (anything that increases heart rate like drugs, atropine, anger, ect.)
What is Starling’s Law
Increasedfilling of the heart results in increased force of cardiac contraction and increased stroke volume (over fill chamber, increase contractions, better stroke volume)
What is reduced blood pressure?
Less pressure to fill the heart, decreased stroke volume (less stretchy, less volume out)
Heart rate increases to compensate for decreased stroke volume
What is the “fight or flight” response?
Sympathetic nervous system releases epinephrine; stroke volume and heart rate increase (increased cardiac output)
What is general anesthesia?
Parasympathetic nervous system releases acetylcholine; stroke volume and heart rate decrease (decreases cardiac output)
What is an electrocardiograph?
Instrument with graph paper that moves under a stylus
What is the P wave?
Depolarization of the atria
What is QRS complex?
Waves created by ventricular depolarization
What is the T wave?
Repolarization of the ventricles
Blood in the systemic circulation is under _______ higher pressure than blood in the pulmonary or coronary circulation
Higher
What are subclavian arteries?
Branch off the aorta and travel toward the thoracic limbs?
What are carotid arteries?
Branch off one or both subclavian arteries
Go straight to brain and kills the animal if you inject here
Directly under the jugular
What are the three important arteries that branch off the aorta?
Renal, ovarian, and testicular
Main trunk of the aorta splits at the hind limbs into the what?
Iliac arteries
Where do coccygeal arteries emerge?
Caudal aorta
Where is oxygen exchanged?
Through capillaries
Venous blood is under _______ pressure than arterial blood
Lower
Veins have _______ walls than arteries
Thinner
What is the cephalic vein?
Most common for dogs and cats
Craniomedial aspect of forelimb
What is the femoral vein?
Medial aspect of hind limb
Most techs like this for cats
What is the saphenous?
Lateral aspect of hind limb
Tibia/fibula region in dogs
What is the vein usually referred to as the milk vein?
Caudal epigastric vein
