Cardiovascular System - Heart as a Pump & Blood Composition Flashcards
what is the cardiovascular system
- transport system that brings nutrients and oxygen to the tissues and removes waste materials from the tissues
- filters: kidney, skin, digestive system…
- blood is medium of transport
location of heart (general/base/apex)
- thoracic cavity and oriented obliquely
- base of heart: directly superiorly, posteriorly, and to the right
- apex of heart: directed inferiorly, anteriorly, and to the left
apex beat
can be felt in the 5th intercostal space
4 types of inspection
- inspection
- palpation
- percussion
- auscultation
coverings around the heart (2)
- outer: fibrous pericardium
2. inner: serous pericardium
fibrous pericardium
tough, connective tissue layer
serous pericardium
- thin, serous membrane
- 2 layers: parietal layer and visceral layer (epicardium)
pericardial cavity
- filled with film of serous fluid (pericardial fluid)
- up to 50mL !
- located between the parietal and visceral layers
pericardial fluid
- friction free environment to protect heart
pericardial effusion
abnormal accumulation of fluid in the pericardial cavity
cardiac tamponade
compression of the heart by an excessive accumulation of fluid in the pericardial sac
structure of heart wall (3 layers)
- epicardium (outer)
- myocardium
- endocardium (inner)
epicardium
visceral layer of pericardium
myocardium (3 layers)
- thick contractile middle layer
- “heart muscle”
- 3 types of cardiac muscle: atrial, ventricular, specialized muscle tissue (coordinates electrical signals)
endocardium
- smooth inner lining of the heart surface
- includes heart valves
carditis
peri, moo, end
heart + infection
different layers
heart chambers
- right atrium
- right ventricle
- left atrium
- left ventricle (has thicccest myocardium - needs to pump blood all around the body)
types of heart valves
- atrioventricular
2. semilunar
atrioventricular valves
mitral
tricuspid
semilunar valves
aortic
pulmonary valve
Law of Laplace for thin-walled spheres
formula sheeeeet
Law of Laplace for thiccc-walled spheres
formula sheet
- development of tension within the walls of the heart produces pressure within the chamber
phases of cardiac cycle
- systole (contractile phase of heart muscle)
- diastole (relaxation phase of heart muscle)
pathway of blood through heart (also know about systole/diastole in relation)
- superior and inferior vena cava
- right atria
- tricuspid valve
- right ventricle
- pulmonary valve
- pulmonary artery
- lungs
- pulmonary veins
- left atria
- mitral valve
- left ventricle
- aortic valve
- aorta
vessels of blood
vains bring oxygenated blood
arteries take away
auscultation and phonocardiogram
auscultation: heart sounds listened to with stethoscope
phonocardiogram: heart sounds recorded by microphone and displayed graphically
specific heart sounds (2)
- valves are pressure-operated; closure of valves produce sounds:
1. corresponds to closure of tricuspid and mitral valves
2. corresponds to the closure of the aortic and pulmonary valves
heart murmurs
- laminar flow is streamlined flow (silent)
- chaotic flow is called turbulent flow (causes additional sounds = heart murmur)
turbulence and relationship to Reynold’s Number
- turbulent flow is estimated from the Reynolds number
- turbulence normally occurs when Re > 2000
turbulence
events in cardiac cycle (4)
- ventricular filling
- isovolumetric contraction
- ventricular ejection
- isovolumetric relaxation
ventricular filling
- ventricles fill for ~0.45s
- mitral and tricuspid valves open
- aortic and pulmonary valves close
- end-diastolic volume = 120mL
- end-diastolic pressure = 4.7mmHg
isovolumetric contraction
- ventricular contraction for ~0.05s
- mitral and tricuspid valves close
- aortic and pulmonary valves closed
ventricular ejection
- takes ~0.30s
- mitral and tricuspid valves closed
- aortic and pulmonary valves open
peak pressure of ~25mmHg (pulmonary circulation) or 120mmHg (systemic circulation) - end-systolic volume 50mL (blood left inside)
isovolumetric relaxation
- lasts ~0.08s
- aortic and pulmonary valves closed
- mitral and tricuspid valves closed
circulatory system consists of:
- heart
- blood
- vasculature (hollow tubes that are conduits for the blood)
blood consists of:
- plasma
- cellular components
3 different cellular components
- erythrocytes
- leukocytes
- thrombocytes
hematocrit
fraction of blood volume occupied by the red blood cells
blood composition (%s)
55% plasma
45% packed and red cells
<1% “buffy coat”
plasma composition
- 90% water
- electrolytes (Na+, Cl-, Ca2+…)
- proteins (albumin, globulins, fibrinogen)
erythrocytes
- most abundant cells in the blood
- carry oxygen bound to hemoglobin!
- anucleate cells
- biconcave disk shape
- max surface area for diffusion of gases
- increased flexibility needed for passing through tiny capillaries
structure of hemoglobin (Hb)
- 4 polypeptide chains (2a, 2b)
- each chain has a heme group
- each heme group has a central iron atom
- an iron atom can bind a molecule of oxygen
- 1 Hb molecule can bind 4 02 molecules
leukocytes (white blood cells)
- protect the body against infections/diseases
- granular and non-granular
- immunity and acquired immunity
granular leukocytes
neutrophils, eosinophils, basophils
non-granular leukocytes
monocytes, lymphocytes
thrombocytes (platelets)
- fragments of large cells called megakaryocytes
- key role in hemostasis (arrest of bleeding)
- form hemostatic plugs that close breaks/tears in blood vessels
- initiate the formation of blood clots (coagulation)
hemorrhage
- opposite of hemostasis
- bleed continues
where do the four valves of the heart lie?
annulus fibrosus
valves are nearly co-planar
