Cardiovascular system Flashcards
Red blood cells rely on ________ metabolism
anaerobic (no
mitochondria, no nucleus (anucleate))
Old RBC’s get trapped and catabolized in the _____
spleen (in red pulp)
spleen also has white pulp rich in _______
white blood cells
the “red blood cell graveyard”
spleen
Shape of RBCs. What maintains this shape?
biconcave disc. maintained by actin-myosin interactions.
where are RBCs made?
in erythroid tissue in red bone marrow
what form do RBCs take when they’re released from erythroid tissue in bone marrow?
reticulocytes (contain some endoplasmic reticulum). within 24 hrs after that they mature into a biconcave disc.
what cavity(ies) does the heart lie in?
the mediastinum (anterior portion) in the pericardial cavity in the thoracic cavity in the ventral body cavity.
systemic circuit
carries blood out and away from the heart to the rest of the body: systemic arteries (aorta away from heart and vena cava to the heart)
cardiac circuit (coronary circulation)
supplies blood to the heart itself: cardiac arteries, cardiac veins…coronary sinus
pulmonary circuit
blood to and from the lungs: pulmonary veins and pulmonary arteries
capillaries
gas exchange vessels
layers of heart wall
epicardium (outer) (aka visceral pericardium), myocardium (middle), endocardium (inner) …parietal pericardium covers the pericardial cavity wall
epicardium
outer layer of the heart. aka visceral pericardium. (parietal pericardium covers the pericardial cavity wall)
-made of areolar tissue and mesothelium, which secretes serous fluid into the pericardial cavity/sac
myocardium
cardiac muscle layer forming the bulk of the heart
Interconnected layers of cardiac muscle tissue
Contracting layer
Forms atria and ventricles
Contains nerves and blood vessels
Endocardium
inner layer of heart wall.
endothelial layer of the inner myocardial surface, lines heart valves and continuous with endothelial lining of blood vessels.
made of endothelium and areolar tissue
-endothelium made up of simple squamous epithelium
parietal pericardium
fibrous outermost layer that lines the pericardial cavity wall.
-mesothelium on inside, secreting serous fluid into cavity
-then areolar tissue
-then dense fibrous layer
pericarditis
disease of the pericardium
myocarditis
disease of the myocardium
endocarditis
disease of the endocardium (including heart valves…like pulmonary valve and tricuspid valve)
describe how atrial and ventricular muscles contract
like skeletal muscle, but the duration of the contraction is longer (longer absolute refractory period). autorhythmic, via contractile fibers and pacemaker/autorhythmic cells.
heart muscle contractions: long or short absolute refractory period?
long. this is why the heart can’t get tenitis.
intercalated discs
function to interconnect cardiac muscle cells (muscle fibers). Allow action potential to move from cell to cell.
Contain desmosomes: hold fibers together, and convey force of contraction
Linked by gap junctions: propagate muscle action potentials
intercalated discs contain ____ and are linked by ____.
desmosomes; gap junctions
function of desmosomes in intercalated discs:
hold the muscle fibers together, and convey force of contraction from one cell to the next
function gap junctions in intercalated discs:
they link the discs to each other and propagate muscle action potentials. allow ions to move from cell to cell.
Cardiac muscle functions as a
_____; heart muscle cells are
interconnected (atrial and ventricular _____)
syncytium
Cardiac cells are ________,
______ and _________
connected = functional syncytium
mechanically, electrically and chemically
in cardiac muscle, SR lacks large _________;
cardiac muscle relies more on
__________ for muscle contraction
terminal cisternae; extracellular Ca
in cardiac muscle, the T tubule is _____ and _____ and encircles the sarcomere at the ______ not the ________
short and broad; Z-lines; zone of overlap
Cardiac cells contain more intracellular _______
and ______ inclusions as most energy is
produced by ____________
glycogen and lipid; aerobic metabolism
triads or no triads formed by t-tubules with cisternae of the SR in cardiac cells?
no triads: short, broad t-tubules and small terminal cisternae of SR
mitochondria in cardiac vs skeletal muscle cells:
much more abundant in cardiac cells (25% of the cell volume)
inclusions in heart vs skeletal muscle
heart: myoglobin, lipids, glycogen (think fatty, bloody heart)
skeletal muscle: less myoglobin and lipids, plenty of glycogen (think lean muscle)
heart is in it for the long haul, needs plenty of oxygen and energy.
active metabolism (not resting) of cardiac vs skeletal muscle:
aerobic in heart (no breath=heart stops…occlusion=not enough oxygen getting to the heart and cells dying. primarily using lipids and carbs). anaerobic in muscle, primarily using breakdown of glycogen reserves.
contraction in cardiac vs skeletal muscle:
heart: twitches w brief relaxation periods. long absolute refractory periods. prevents tetanic contractions.
skeletal: usually sustained contractions.
stimulus for contraction in cardiac vs skeletal muscle cells:
trigger for contraction:
autorhythmic cells vs motor neuron impulses that generate action potential in sarcolemma
cardiac: calcium entry from extracellular fluid, and calcium release from SR
skeletal: just calcium release from SR
coronary arteries:
Branch from base of aorta. supply blood to the heart.
coronary veins:
deoxygenated.
* Path follows coronary arteries
* Join together at coronary sinus
* Empty back into right atrium to go to pulmonary circuit again
Right atrium
Collects deoxygenated
blood from systemic
circuit and coronary
sinus
right ventricle
Pumps deoxygenated
blood to pulmonary
circuit via pulmonary
artery
left atrium
Collects oxygenated
blood from pulmonary
circuit (pulmonary veins)
left ventricle
Pumps oxygenated blood to systemic circuit
Superior vena cava:
Receives blood from
head, neck, upper limbs, and chest
Inferior vena cava:
Receives blood from
trunk, viscera, and lower limbs
Coronary sinus:
Cardiac veins return blood
to coronary sinus. enters into right atrium to be returned to pulmonary circuit.
Foramen ovale
Before birth, is an opening through interatrial septum (for-amen…prayer for the fetus. ovale: one perfect baby.)
Seals off at birth, forming fossa ovalis (even fossils have the fossa ovalis. ovale matures to gain a letter.)
foramen ovale:
opening in the interatrial septum in fetuses to circumvent the pulmonary circuit (unnecessary).