C-1 Flashcards
VASCULAR SYSTEM
Consists of:
Forms two circuits:
no loss of blood considered normal
Consists of:
ARTERIES- blood vessels that take blood away from the heart.
VEINS-taking blood toward the heart.
Two circuits:
PULMONARY- from the heart to the Lungs and back.
( refers to oxygenation- NO TRANSPORT)
SYSTEMIC- from the heart to the body and back. (Transports to all tissues of the bodies)
STRUCTURE OF THE HEART
Location
Size
Orientation
Location: thoracic cavity
Average adult size: Ht: 14cm, Wt: 9cm
Orientation:
Base=superior aspect situated at 2nd rib. ( location of the great vessels, Aorta &;pulmonary)
name based on function
Apex= inferior aspect, situated at approx the 5th &6th ribs
Structure of the heart
PERICARDIUM and layers.
-Also refers to the pericardial sac
-Consists of 3 layers
1- outer FIBROUS layer- mostly DENSE IRREGULARS CONNECTIVE tissue *protective
2-Parietal layer- SEROUS MEMBRANE, adherent to the inside of the Outer Fibrous layer. Produces a thin watery fluid.
3-Visceral layer- SEROUS MEMBRANE, adherent to the external of the heart. Produces a thin watery fluid.
Serous layer=simple squamous
Heart structure
PERICARDIAL CAVITY
- Space between the parietal and visceral layers
- contains a small amount of serous fluid
- helps reduce friction as the heart moved
- heart never stops contracting until you die; start 4 was after conception
Heart structure
WALL OF THE HEART
Epicardium=visceral pericardium (outer layer) serous membrane covering the heart
Myocardium= middle layer. Cardiac muscular tissue.
Endocardium= inner layer, lines the internal surfaces
- epithelium with underlying connective tissue
>smooth with various structures
Structure of heart
CHAMBERS
Basic info
Heart is two separate pumps working in parallel.
»systemic: left side
»pulmonary: right side. Both sides are not connected
- no connection between sides except in fetal development
- each side consists of two chambers working in SERIES
» left side: atrium then ventricle =systemic
» right side: atrium then ventricle = pulmonary
Heart structure
CHAMBERS continued
Left side (systemic circulation)
-Atrium receives blood from the lungs (just oxygenated)
- Ventricle receives blood from the Left Atrium
(Pumps blood to the body) oxygenated-> body
Right side ( pulmonary circulation)
- atrium receives blood from the body
- ventricle receives blood from the Right atrium
»pumps blood to the lungs
Heart structure
Heart Valves found between:
- chambers of each side of the heart
- chambers and large vessels leaving the heart
- Atrioventricular valves (AV)- between atria & ventricles
- Semilunar- leaves heart
Aorta
Pulmonary
Heart structure
Atrioventricular (AV) heart valves
Right side
Left side
Atrioventricular
>unidirectional
> composed cusps (leaflets) - flap on inferior side
> CHORDAE TENDINAE
Strong fibrous strings attached to the inferior sides of the cusps to keep them from prolapsing (opening in opposite direction)
> PAPPILARY MUSCLES - cardiac tissue where the CHORDAE TENDINAE originate from - make taut when the muscle contracts
Right side: tricuspid
Left side: bicuspid
> also cakes the mitral valve
> left side fails the most
Heart structure
SEMILUNAR VALVES
- unidirectional
- found at the base of the great vessels leaving the heart
> Aorta
> pulmonary trunk - valves
> 3 cusps - shape resembles half moon
> NO CHORDAE TENDINAE
> NO attachment to PAPPILARY muscles
Heart structure
Heart Sounds - Valves
- created by the vibrations of the valves moving - i.e. Closing of valves
- normally the heart has two sounds
1. AV valves closing (bicuspid/tricuspid) - occurs when ventricles contract»_space; blood pushes valves closed
- Pulmonary & aortic valves closing - occurs when the ventricles relax
» pressure in the ventricles decreases
» blood tries to return to the ventricles closing the valves
Heart sounds
Where they can be heard
- AV valves
- bicuspid - heard:5th intercostal space at nipple line in left
- tricuspid- heard: 5th intercostal space just to the right of the sternum - Pulmonary & Aortic valves
- pulmonary valve: heard: 2nd intercostal space just to the left of the sternum
- aortic valve: heard: intercostal space just to the right of the sternum
Blood flow of the Heart
10
- Enter the right atrium from the body
- Passes thru tricuspid valve
- Enters right ventricle
- Passes through the pulmonary valve
- Enters pulmonary arteries then to lungs
- Returns to the left atrium via pulmonary vein
- Passes thru the bicuspid valve
- Enters the left ventricle
- Passes thru the aortic valve
- Enters the aortic arch to the body
Left and right happening. At the same time !!
Heart structure
Blood supply to the cardiac tissue
-the blood that supplies the heart tissue it’s nutrients does NOT come from the blood that is moving thru the heart.
- CORONARY ARTERIES- vessels for the hearts own blood supply i.e. Oxygen
- first two branches off the aorta as it leaves the left ventricle
>R coronary artery
> L coronary artery
Right coronary artery branches off to
Anterior: marginal artery-right atrium and ventricle
Posterior: posterior interventricular artery- ventricles
Left coronary artery branches off to
Anterior: anterior inter ventricular artery (LAD)-ventricles
Posterior: circumflex artery- left atrium and ventricle
Systole:
Diastole:
Systole: contraction of a heart chamber ( atrium or ventricle)
Diastole: non- contracting state, relaxation of a heart chamber (atrium or ventricle)
Cardiac cycles two perspectives
Mechanical: generation of force
Electrical: movement of ions s
Work together
Cardiac cycle is the:
Repeating pattern of contraction and relaxation
- Atrial systole (contraction) - moving blood to ventricles
- Atrial diastole (relaxation)
- Ventricular systole (contraction)
- Ventricular diastole (relaxation) & atrial diastole (relaxation)
Always in this sequence, specific timing
Whenever there is a variation= heart disease
Cardiac cycle - MECHANICAL :
- Atria fills with blood from venous system - occurs during relaxation (diastole) of both atria and both ventricles
- As volume in atria increases, pressure in the atria increases
- Causes bicuspid/tricuspid to open before the atria contract *70% of the volume filling the ventricles occurs BEFORE atrial systole (contraction)
- valves always open as they are relaxed - Atria then contract to add the last additional 30% “top off ventricles” ventricles have been in diastole the entire time
- Atria relax (diastole) and the ventricles contract (systole). - ventricles pump out 2/3 of their volume , 1/3 of the volume remain in the ventricles
- Ventricles then relax (diastole), atria are still in (diastole)
- Sequence starts over as atria begin to fill
One sequence= one cardiac cycle = heartbeat = pulse
- FACTS of the heart
- FUNCTION of the heart
FACTS
-muscular pump
-average blood volume male:5liters; women: 4liters
- moves the total blood volume thru entire system male: 1400 times
Woman: 1750 times
FUNCTION: transport, to get the body’s essential substances to the body’s tissue (creates the force)
