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tetanus of cardiac muscle is prevented by:
a long refractory period
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blood flow through all organs is:
passive and occurs only because arterial presure is kept higher than venuous pressure dup to pumping of the heart
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term for action potentials generated by the heart:
autorhythmicity
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Where is the sino atrial node?
the right atrium
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what divides the heart?
the septum
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heart Oo. what do calcuim channel-blocking drugs do?
reduce calcium influx during an action potential and reduce the force of contraction
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What is the most serious arrhythmia?
ventricular fibrillation which is when the wave of depolarization may re-enter and produce circular movements around the heart. the muscle only quivers -> patient loses consciousness and dies
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What happens if the atria fibrillate?
the heart continues to pumt but with lower ouput.
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what are the layers of the arteries?
- inner layer- simple squamous epithelium == endothelium
- middle layer - smooth muscle and elsastic connective tissue
- outer layer- elastic and collagen fibers
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veins]?[arteries
veins have a thicker outer layer, thinner middle layer, and very thin endothelial layer that fols inward at intervals forming valves
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mean arterial pressure = X pulse pressue?
1/3
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what is arterial blood pressure measured with?
a sphygmomanometer
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what is the name for the first sound heard via the stethescope that corresonds to systolic blood pressure?
Korotkoff's sounds
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What is the major resistance vessels of the circulatory system?
arterioles
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systolic-to-diastolic swings in pressure conver to ____ as blood flows through the arterioles
nonpulsatile pressure
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2 mechanism of arterial pressure =
- fast, neurally mediated baroreceptor reflex (stretch receptors in the carotid sinus (.oO neck) -> increases firing of the cartid sinus nerse -> vasomotor center in the brainstem |?:. lowers pressure .:|
- a slow, hormonal mechanism which regulates blood volume (ADH and aldosterone)
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hemostasis consists of what 3 processes?
vasoconstriction, platelet plug formation, blood clot formation
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3 steps of blood clotting:
- 1. formation of prothrombinase (prothrombin activator)
- 2. conversion of prothrombin (formed by liver) into thrombin (a proteolytic enzyme) by prothrombinase
- 3. conversion of frbrinogen (solbume plasma protein formed by liver) intofibrin (insoluble) by thrombin
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extrinsic coagulation pathy way is initiated by ___
a tissue factor (thromboplastin)
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sarcomere shortening is known as :
the sliding-filament mechanism
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which part of the sarcomere shortens during contraction?
the i-band
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role of calcium in muscle contraction (skeletal):
calcium ions trigger muscle contractino by binding to one of the molecules in troponin, causing a change in the shape of the molecule such that tropomyosin slides away from its blocking position on actin molecules -> actin and myonsin bind to form the cross bridge
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brain]?[skull
cerebrospinal fluid
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blood from the coronary arteries is returned to the heart via the:
coronary sinus
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____ is released from the thyroid gland
calcitonin
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proteolytic enzyme ___ converts fibrinogen to fibrin
thrombin
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glucose is reabsorbed in the ___
proximal tubule
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parasympathetic nerve stimulation ____ pacemaker cells in the SA node
hyperpolarizes
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what stimulates contraction of smooth muscle in the uterus?
oxytocin
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what are the function of a nephron?
to eliminate wates from the body, regulate blood volume, blood pressure, and blood ph, and to regulate electrolytes and metabolites
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in flow order: nephron (s)o. ?
glomerular capillary, Bowman's space, proximal tubule, |loop of Henle :. thin descending limb, thin ascending limb, thick ascending limb, early distal tubule, late distal tubule}{collecting ducts
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angiotensinogen --?--> angiotensin
renin
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what does angiotensin do?
potent constrictor of blood vessels, acts on kidney's to release aldosterone, stimulates thirst via the hypothalamus
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what does aldosterone do?
.o(c)?
- increases reabsorbtion of Na and H2O and releases K into urine,
- -->increases blood volume
- --> stimulates ADH
- mineralocorticoid .oO steriod
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epinephrine ==
adrenaline
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what is the leading cause of blindness?
- diabetic retinopathy
- Oo. protein glycosylation
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glycogen --?--> glucose
glucagon
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how does insulin accelerate glycogen formation within a cell?
bding to a plasma membrane receptor --> vesicles containing glucose carriers merge with the plasma membrane
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Where is a decrease in oxygen levels detected?
in chemoreceptors at the top of the heart
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what are the layers of the heart and what is each layer composed of? (5 keywords)
endocardium - then layer of endothelium, myocardium- cardiac muscle, epicardium- thin external membrane covering the heart .oO heart, pericardial fluid, pericardial sac
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what prevents backflow of blood into the heart?
aortic and pulmonary}{semilunar valves
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cardiac output =
stroke volume * beats/min
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what helps conduct cardiac muscle APs?
gap junctions
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smooth muscle (s)o.?
intermediate filaments which stretch between dense bodies, composed of the same proteins as in Z lines
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transverse tubules=
invaginations of the plasma membrane into the muscle fiber occuring @ each junction of an A band and I bands
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anabolic steroids -->
adverse effects (5):
- hypertrophy of skeletal muscle
- liver dysfunction, decreased sperm production, sterility in females, increased risk of heart disease, aggressive behavior
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the SR surrounds __
each myofibril
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heart attack ==
infarction
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using a ballon catheter to try to remove a blood clot ==
angioplasty
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if a clot returns after angioplasty ==
restonosis
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skeletal muscle (s)o. ___ Oo. ___ Oo. ___ Oo. ___ & ___
muscle fasicle, muscle fiber (cell), myofibrils, thick and thin filaments
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in muscle contraction: Ca binds to ___
troponin
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fast][slow twitch skeletal muscle
- slow: dark (many mitochondria), slow rate of hydrolysis of ATP on myosin
- fast: white, less mitochondria, good for short busts of energy
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a gap junction contains
aqueous pores
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