2. cardiovascular system Flashcards
cardiovascular system
- heart, blood vessels, blood
- transport: gases, nutrients, hormones, wastes, heat
- protection: disease, fluid loss (clotting)
heart
-in a cavity called the mediastinum (=space b/w lungs w/in thoracic cavity)
heart structure
- coverings=pericardium
- heart wall
- chambers and associated blood vessels
- septa (separate chambers)
- fibrous skeleton
- valves
- cardiac muscle cells
- conduction system
coverings = pericardium
-double-walled sac surrounding heart
-between pericardium layers = pericardial cavity with serous fluid (lubricates)
-3 layers:
fibrous pericardium
serous pericardial layers - 2 parts
fibrous pericardium
- outermost layer=dense irregular CT
- anchors to surrounding structures
eg. diaphragm,great vessels (aorta, vena cava, etc)
serous pericardium- 2 parts
- parietal pericardium
- visceral pericardium = epicardium
parietal pericardium
fused to fibrous pericardium
fibrous pericardium and parietal pericardium = pericardial sac
visceral pericardium
=epicardium
-fused to heart surface, so is part of heart wall
heart wall
3 parts:
epicardium
myocardium
endocardium
epicardium
stratified squamous epithelium and CT
myocardium
=cardiac muscle
-arranged in spiral/circular pattern, reinforced with CT
endocardium
- simple squamous epithelium and CT
- epithelium named endothelium-lines inner surface of heart and all blood vessels
Chambers and associated blood vessels
right atrium
left atrium
right ventricle
left ventricle
right atrium
- inferior and superior vena cava
- coronary sinus (posterior)
left atrium
4 pulmonary veins
right ventricle
pulmonary trunk-divides to form 2 pulmonary arteries
left ventricle
aorta
septa (separate chambers )
inreratrial septum
inter-ventricular septum
inreratrial septum
separates atria
interventricular septum
- separates ventricles
- deep to inter-ventricular sulcus (external)
fibrous skeleton
- CT fibers around the muscle fibers and CT rings b/w atria and ventricles at the coronary sulcus
- allows openings to remain open at all times (valves open and close)
- provides electrical insulation-prevents simultaneous contraction of chambers
valves
- atrioventricular (AV) valves
- semilunar valves
atrioventricular valves
*chordae tendineae (CT) attach AV valve cusps to papillary muscles (projections of myocardium)
(prevent eversion of cusps)
-bicuspid (mitral) valve (left side- 2 cusps)
-tricuspid valve (right side- 3 cusps)
semilunar valves
-3 cusps each
*aortic
(separates left ventricle and aorta)
*pulmonary
(separates right ventricle and pulmonary trunk)
cardiac muscle cells
form both contractile myocardium and conduction system
cardiac muscle cells similarities to skeletal muscle:
- striated (myofibrils with sarcomeres)
- has sarcoplasmic reticulum and T-tubules
cardiac muscle cells differences to skeletal muscles:
- branched (myofibrils with sarcomeres)
- uninucleated
- intercalated discs=region where two fibers meet
- contain anchoring and gap junctions
conduction system
- cardiac muscle cells modified to produce and conduct electrical impulses - DO NOT CONTRACT
- note: electrical signal spreads from conduction system to contractile cardiac cells then they contract
conduction system parts
- sinoatrial (SA) node
- atrioventricular (AV) node
- atrioventricular bundle (bundle of his)
- atrioventricular (AV) bundle branches
- purkinje fibers
Sinoatrial (SA) node
- in right atrium at base of superior vena cava
- generates impulses the fastest-sets pace
atrioventricular (AV) node
-base of right atrium
atrioventricular bundle (bundle of his)
- superior part of interventricular septum
- electrically connects atria to ventricles
atrioventricular (AV) bundle branches
got to each ventricle
purkinje fibers
-terminal fibers in ventricles only
circulatory routes
- closed, double circulation
- closed = blood confined to heart and blood vessels
- double = 2 routes (pulmonary and systemic)
- adult circulation and fetal circulation
adult circulation
- pulmonary circulation
- systemic circulation
- coronary circulation (visible externally)
pulmonary circulation
- right ventricle to lungs by pulmonary arteries (deoxy blood)
- pick up oxygen in lungs by capillaries
- lungs to left atria by pulmonary veins (oxygenated blood)
Systemic circulation
-left ventricle to organs by aorta (oxygenated)
-organs remove oxygen by capillaries
-organs to right atrium by superior and inferior vena cava (deoxygenated)
-overall route: left ventricle to right atrium = systemic circulation
*subdivisions/subroutes:
cerebral=brain
hepatic=liver
coronary=heart
coronary circulation
visible externally (chart on page 4)
fetal circulation
- fetus gets O2, nutrients from and expels wastes to mother’s blood
- exchange site in the placenta
- blood supplies in close together, but do not mix
fetal circulation differences from adult circulation
a) umbilical vein (towards the fetal heart)
b) lungs and liver basically non-functional
c) umbilical arteries (away from fetal heart)
umbilical vein
- towards the fetal heart
- carries oxygenated blood from placenta to vena cava
lungs and liver basically non functional
3 shunts to bypass (although some blood flow to these organs for nourishment/growth)
- ductus venosus
- foramen ovale
- ductus arteriosus
ductus venosus
- connects umbilical vein (oxy blood) to inferior vena cava (doexy blood) to bypass liver - permits most of the oxygenated blood coming from the placenta to bypass the liver
- oxy and deoxy blood mixes
- mixed blood enters fetal heat by inferior vena cava
foramen ovale
-hole in interatrial septum
-allows blood to move from the right to left atrium
(bypass lungs)
ductus arteriosus
-connects pulmonary trunk and aorta (bypass lungs)
umbilical arteries
- away from fetal heart
- returns mixed blood to placenta
anatomy of blood vessels
- general structure of blood vessels (except capillaries):
1. tunica externa - CT
2. tunica media - smooth muscle
- elastic fibers (CT)
3. tunica intima/intema - endothelium-simple squamous epithelium
4. lumen-contains blood (not a layer)
blood vessel types (following path from heart and back to heart):
- arteries
- arterioles
- capillaries
- venules
- veins
arteries
carry blood away from heart (does not refer to oxy of deoxy)
2 types:
elastic arteries
muscular arteries
elastic arteries
- elastic CT in all 3 layers
- largest arteries (near heart)
eg. aorta
muscular arteries
- a lot of smooth muscle
- most arteries
eg. coronary artery
arterioles
- little arteries
- regulate blood flow and blood pressure
capillaries
- only tunica intima-endothelium (on cell layer) + basement membrane
- allow exchange of gases and nutrients
- gaps allow limited fluid and solutes to leak out = interstitial fluid (ISF)
- capillaries unite to form venules
venules
-intima, thin media, thin externa
veins
- large lumen
- valves prevent backflow of blood
- thin media-less smooth muscle
- can collapse
Blood (CT) characteristics
- higher viscosity than water
- 37 degrees c
- ph 7.35-7.45
- 4-6 L in an adult
blood (CT) composition overview
- plasma (matrix)
* fluid portion with solutes - formed elements
* cellular portion
plasma (matrix)
=blood minus formed elements -composed of : H2O-90% proteins-8% -albumin-control tissue water balance -fibrinogen-clot formation -globulin-antibodies other solutes-2% (nutrients, hormones, wastes, electrolytes, gases)
formed elements
- RBC-erythrocytes
- WBC-leukocytes
- platelets
RBC- erythrocytes
- hematocrit
- bioconcave disc shape
- anucleate when mature
- life span-120 days
- destroyed in the liver and spleen
- contain hemoglobin
hemoglobin
- pigment protein
- hemoglobin is broken down to heme and globin
- heme is further broken down to bilirubin
- Fe2- recycled or stored (toxic, so always bound to protein)
- globin to amino acids
i. heme=red pigment-contains iron (Fe) - attaches and transports O2
ii. globin-protein - attaches and transport CO2
WBC-leukocytes
-nucleated
-life span varies - days to years
-defend against disease
-2 types:
granulocytes
agranulocytes
WBC granulocytes
includes: neutrophils 60% *all phaghocytic (engulf and digest invaders) *kill bacteria eosinophils 3% *attack parasites (eg. worms) basophils 1% *release: histamine (increase inflammation) and heparin (decrease local clotting)
agranulocytes
include: monocytes 5% *enter tissue + enlarge to become macrophages (phagocytic = big eaters) lymphocytes 35% immunity -2 types : T lymphocytes *kill infected/diseased cells directly B lymphocytes *become plasma cells, produce antibodies (=y globulin)
Platelets
- fragments of cells called megakaryocytes
- involved in clotting
- life span = ~10 days if not used for clotting
Hemopoiesis/Hematopoiesis
-=formation of blood cells
-all blood cells arise indirectly from hemocytoblast (=stem cells) cells in red bone marrow
*red marrow in adult:
axial skeleton
pelvic and pectoral girdles
proximal ends of humerus and femur
