PTA - section 2 Flashcards
SYSTEMIC CIRCUIT
- vessels carry blood from the heart to the tissues and back to the heart
PULMONARY CIRCUIT
- vessels carry blood from the heart to the lungs and back to the heart
OXYGEN POOR, CO2 RICH
-blue
OXYGEN RISH, CO2 POOR
- red
THE HEART COVER
- covered in a sack of pericardium, that has fluid to help with friction during contraction
VENTRICLES
-occupy the bulk of the heart
ARTERIES AND VEINS
- are attached to the base of the heart
- visible on the surface of the heart
- enter heart walls to deliver oxygen & nutrients & waste
CORONARY SINUS
- delivers deoxygenated blood to right atrium
VENTRICLE THICKNESS PULMONARY
- low pressure, low resistance, less thickness
VENTRICLE THICKNESS SYSTEMIC
- high pressure, high resistance, thicker wall
MYOCARDIC MUSCLES
- fibres arranged spirally
- spiral provides ringing effect at contraction which squeezes blood upward from apex
DESMOSOMES
- strong connection of force from one cardiac cell to another
GAP JUNCTIONS
- channels allow ions to spread from one cell to another
INTERCALATED DISKS
- contain desmosomes and gap junctions
INLET
- right (AV) tricuspid, left (AV) bicuspid
OUTLET
- pulmonary semi- lunar valve, aortic semi lunar vavle
1ST STEP OF BLOOD FLOW
- av valves open in left ventricle, atrial pressure is great than venticle pressure
SEMILUNAR VALVES WHAT DO THEY DO
- prevent the black flow of blood during ventricular filling
FLAP CONNECTED TO PAPILLARY MUSCLES
- prevent flaps from being push backed into the atrium when the ventricles contract
2ND STEP OF BLOOD FLOW
- AV valves close, ventricle pressure greater than atrial pressure, aortic semilunar vavles open
HEART SOUNDS
- Closure of heart valves creates turbulent flow
1ST SOUND
- inlet AV valves closing lubb
2ND SOUND
- outlet valves closing dupp
CARDIAC VS SKELETAL SIMILAR
- striated
- sarcomere structure
CARDIAC VS SKELETAL DIFFERENT
- muscles fibres shorter cardiac
- braches
- singular nucleus
CARDIAC VS SMOOTH SIMILAR
- electrically linked to one another
- exhibit pacemakers
- under sympathetic and para control as well as hormone
CARDIAC VS SMOOTH DIFFERENT
- gap junctions in intercalated disks
PACEMAKER
- helps maintain the heartbeat
- used to speed up slow heart beats
- maximize heart circulation
BRADYCARDIA
- heart beat too slowly
TACHYCARDIA
- fast beating heart
PACEMAKER STRUCTURE
- battery
- pulse generator
- electrodes to heart
TEMPORARY ENDOCARDIAL (transvenous) PACE
- the pulse generator is the outside heart
- tempory abnormality
- waiting for permanent
- right atrium make connect with endocardium
EXTERNAL PACE (transcutaneous)
- emergency
- generator outside
TEMPORARY EPICARDIAL PACE
- surgery
- can cause inflammation
- bradycardia
PERMANENT (internal)
- heart block - 3d & 2nd degree
- symptomatic sinus bradycardia
Most of the cardiac muscle of the heart is found in the:
Myocardium
The right ventricle pumps _______ blood into the _______ circulation.
deoxygenated; pulmonary
The _______ supply oxygenated blood to the heart muscle itself
coronary arteries
The wall of the left ventricle is thicker than the wall of the right ventricle because the:
Left ventricle must pump the same amount of blood into the high-resistance, high-pressure systemic system as does the right ventricle into the low-resistance, low-pressure pulmonary system
How is blood drained by the tissues of the heart?
Mainly into the coronary sinus, which empties into the right atrium
Which chamber of the heart has the thickest musculature?
Left ventricle
The function of the pericardial fluid is to:
reduce friction between the heart and the pericardium
Chordae tendinae are strands of connective tissue extending from________ to ________?
AV valves : papillary muscle
Which of the following is NOT a component of the pulmonary circuit?
Vena cava
The source of blood carried to capillaries in the myocardium would be_______
coronary arteries
EC COUPLING CARDIAC 1
- action potential enters from adjacent cells
EC COUPLING CARDIAC 2
- voltage gated ca2 channels open, ca2 enters cells
EC COUPLING CARDIAC 3
- ca2 induces ca2 release through RYR channels
EC COUPLING CARDIAC 4
local release ca2 sparks
EC COUPLING CARDIAC 5
- summed ca2 sparks create a ca2 signal
EC COUPLING CARDIAC 6
- ca2 ions bind to tropinin to initate contraction
EC COUPLING CARDIAC 7
- relaxation occurs when ca2 unbinds from troponin
EC COUPLING CARDIAC 8
- ca2 is pumped back into sacroplasmic reticulum for storage
EC COUPLING CARDIAC 9
- ca2 is exchanged with a by NCX antiporter
EC COUPLING CARDIAC 10
- na gradient is maintained by Na k atpase
EC COUPLING CARDIAC VS SKELETAL
- initiation of actional potential
- source and role of ca2 in muscle contraction
- muscle relaxation - handling of unbound ca2
FRANK STARLING MECHANISM 1
- crowding do to actin overlap
- no force
FRANK STARLING MECHANISM 2
- actin overlap due to polarity
- force same
FRANK STARLING MECHANISM 3
- no problems / no overlapping
- lots of force
FRANK STARLING MECHANISM 4
- really stretched
- actin is out of reach
- no force
FRANK STARLING LAW
The law states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction (the end diastolic volume), when all other factors remain constant.
In excitation-contraction coupling in myocardial contractile cells, Ca2+ induces Ca2+ release from the sarcoplasmic reticulum through:
Ryanodine receptor channels (Ryr)
When a cardiac contractile cell is stimulated:
Voltage-gated Ca2+ channels open. Ca2+ enters the cell
From the point of Ca2+ diffusing through the cytosol to the contractile elements, what step below is unique to cardiac contractile muscle cells compared with skeletal muscle cells?
Ca2+ is removed from the cell via a Na+- Ca2+ exchanger
In excitation-contraction coupling in myocardial contractile cells, the Ca2+ that causes contraction comes from:
The opening of Ca2+ -sensitive channels in the sarcoplasmic reticulum that have picked up calcium from the extracellular fluid
AUTHORHYTHMIC CELL ACTION POTENTIAL
- sa node =pacemaker
- funny channel open, then close at -40 ca open
- ca close at threshold, k open, close at -60
CONTRACTILE CELL ACTION POTENTIAL
- na open na close ca opn, fast k close ca close, slow k open resting
REFRACTORY PERIOD OF CARDIAC CELL
- force of contraction can be graded = to how much ca enters
If channels are permeable to:
Na+ and K+