Exam 1 (Cardio) Flashcards
Effect of BoTX
Affect synaptic transmission via disruption of SNARE proteins.
Cause flaccid paralysis and autonomic symptoms, affecting peripheral cholinergic fibers.
Effect of TeTX
Affect synaptic transmission via disruption of SNARE proteins.
Mainly taken up by inhibitory neurons in the spinal cord resulting in lethal spastic paralysis.
EPSP
Excitatory Postsynaptic Potentials
Release Ach or glutamate. Increase probability of AP
IPSP
Inhibitory Postsynaptic Potentials
Release glycine or GABA. Reduce probability of AP occurring. Allow for CHLORIDE to rush in and RMP gets stuck at 65 (Cl- potential)
Sarin gas works by…
Inhibiting AChE and causing death via overstimulation
Cardiac E-C coupling vs Skeletal vs Smooth
CARDIAC: AP –> L-type Ca2+ into T-tubules –> Ca2+ activation of DHPR –> RYR activation –> Ca2+ release from SR –> cross-bridge formation
SKELETAL: AP travels into T-tubules –> voltage based activation of DHPR –> RYR activation –> Ca2+ release from SR –> cross-bridge formation
SMOOTH: Some stimulation (AP to voltage gated Ca2+ channel; Hormone or NT to IP3 or Ligand gated Ca2+ channel) –> Ca2+ influx –> Ca2+ binding to calmodulin –> Myosin kinase activation–> contraction –> myosin phosphatase –> relaxation
3 general requirements for re-entry of excitation
(1) GEOMETRY for a conduction loop
(2) SLOW or DELAYED conduction
(3) UNIDIRECTIONAL conduction block
alpha receptors
Located on vascular smooth muscle; causes vasoconstriction.
Coronary and cerebral vessels have little sympathetic vasoconstrictor innervation.
beta-1 receptors
primary adrenergic receptor on cardiac muscle; stimulates heart rate and contractility
beta-2 receptors
primarily located on vascular smooth muscle; causes vasodilation
secondary adrenergic receptor on cardiac muscle; stimulates heart rate and contractility
venous pressure
5
right atrial pressure (mean)
2
right ventricle pressure (systolic)
25
right ventricle pressure (end-diastolic)
2
Pulmonary artery pressure (systolic)
25
Pulmonary artery pressure (diastolic)
10
Pulmonary artery pressure (mean)
15
Pulmonary wedge pressure
Indirect measurement of left atrial pressure
6
Left atrial pressure (mean)
6
left ventricle pressure (systolic)
120
left ventricle pressure (diastolic)
6
Brachial artery pressure (mean)
95
Renin-Angiotensin- Aldosterone mechanism
Used for long-term regulation of blood pressure
Low arterial pressure –> baroreceptors (or sometimes directly sensed in renal arterioles) –> Renin release from renal JGA converts Angiotensinogen to Angiotensin I –> ACE in endothelial cells of the lungs and kidneys converts Angiotensin I to ANGIOTENSIN II
Angiotensin II Function
- vasoconstriction of renal and systemic vessels
- stimulates aldosterone release from adrenal cortex, leading to increased Na+ reabsorption in kidney
- Acts on hypothalamus to stimulate thirst and ADH
Poiseuille’s Law (and the 2 associated laws) Don’t include constant values.
Used to determine flow
F= P/R
F= [(P1-P2) x r^4]/ L x viscosity
R = (L x viscosity)/ r^4
Laplace relationship
Used to determine wall tension
T= (Pxr)/ wall thickness
Cardiac Output
Heart rate x Stroke Volume
Viscosity
Slipperiness
Shear stress/ shear rate …. or…. pressure/velocity
Reynold’s number
Indicates likelihood of turbulent flow (NR > 3000)
Reynolds Number (NR)= [density(velocity)diameter]/viscosity
a, c, and v waves (CARDIAC CYCLE)
a- pressure from atrial contraction
c- mitral valve bulging back into atria during ventricular contraction
v- caused by filling and emptying of atria (begins during isovolumic relaxation)
physiological splitting
aortic valve closes slightly before pulmonic valve (exaggerated during inhalation)
persistent splitting
caused by right bundle branch block
increases split between aortic valve and pulmonary
paradoxical splitting
caused by left bundle branch block
pulmonary valve closes before aortic
1st heart sound
closing of mitral (bicuspid) and tricuspid valves
2nd heart sound
closing of aortic and pulmonary valves
3rd heart sound
Pathological
Caused by rapid filling of a dilated ventricle (usually during cardiomyopathy)
4th heart sound
A strong contraction of the atria, physiologically associated with athletes and children.
Gallop
hearing the 1st, 2nd, and 3rd heart sounds
Diastasis
Middle stage of diastole when passive filling has slowed but the atrial “kick” has not yet arrived.
Relative atria pressure before and after birth and how that affects flow (no need for numerical values)
Right atria = higher pressure before birth
This allows flow through foramen ovale and keeps blood away from lungs. This decrease is caused by uterine contractions and eventual cord clamping.
After birth, left atria= higher pressure. This closes the foramen ovale
What accounts for easier passage of blood into the pulmonary vasculature at birth?
With the first breath, alveoli are opened, pulmonary capillaries open and pulmonary vascular resistance drops.
What causes decreased flow across the ductus arteriosus (connects pulmonary artery to aorta)? What causes its eventual closing
Increased systemic pressures (crying, moving, no placenta). Bradykinin produced in lungs causes its eventual closing.
Apgar scale (categories + highest rating)
HR, RR, Color, Tone, Irritability (2 points max, so high of 10 points)
CPP
Cerebral Perfusion Pressure
Mean arterial pressure - Intracranial venous pressure.
A decrease in MAP or an increase in Intracranial pressure can reduce cerebral perfusion pressure and cause ischemia.
Agents which serve as vasodilators (especially in the brain)
Adenosine (released due to ischemia), K+, NO.
Cushing Response
An elevation in intracranial pressure causes:
(1) Increased BP (due to sympathetics)
(2) Decreased HR (due to parasympathetics)
(3) Irregular respiration (due to brainstem damage)
Autoregulation of pulmonary vessels
They DO NOT autoregulate
Most important control factor for skin blood flow
Neural control (NOT metabolic)
Apical skin
Present on nose, lips, hands, etc.
- favors heat loss
- contains specialized AV anastomoses called glomus bodies which facilitate heat loss
- vasoconstricted at rest, vasodilates passively
Nonapical skin
- Lacks AV anastomoses
- Exhibits vasodilation as sweat glands via sympathetic release of Ach
- Also exhibit the usual NE induced vasoconstriction
Mean Circulatory Pressure
Pmc. The mean pressure that exists in the circulatory system when cardiac output stops. It is the “fullness” of the system.
2 things influence it:
(1) absolute blood volume
(2) venous tone
3 main points regarding splanchnic regulation
(1) Blood flow usually determined by rate of active transport of solutes across mucosal epithelium. Flow increases due to metabolism and increased O2 demand
(2) Sympathetics are the major neural control and cause constriction
(3) Parasympathetics cause INDIRECT stimulation of intestinal blood flow via increasing motility and glandular secretions
Increased tone will cause what change to compliance?
Decreased compliance
Physical characteristics of an artery
TUNICA INTIMA- connective tissue + internal elastic lamina
TUNICA MEDIA- smooth muscle and External Elastic Lamina
TUNICA ADVENTITIA- connective tissue + smooth muscle + vessels and innervation.
Physical characteristics of a vein
TUNICA INTIMA- connective tissue
TUNICA MEDIA- very little smooth muscle
TUNICA ADVENTITIA- well developed connective tissue + little smooth muscle + vessels
Prostacyclins
VASODILATOR
Increases cAMP to phosphorylate MLCK, inhibiting its functioning and decreasing actin-myosin interaction
Endothelin
VASOCONSTRICTOR
Cause release of calcium via IP3, increasing calmodulin functioning therefore contraction.
Chemoreceptor functioning
Primarily activated by low PO2, but also affected by high PCO2 or low pH.
Primarily involved with regulation of respiration
Cause increased HR and BP (via symp. stimulation and eventual blockage of para.)
What organs have strong autoregulation? Weak autoregulation? Little to no autoregulation?
STRONG: heart, brain, kidneys, muscle
WEAK: splanchnic circulation
LITTLE: skin, lungs
Factors which shift the cardiac function curve
Afterload and contractility
Factors which shift the vascular (venous) function curve
Blood volume and venous tone
Ductus venosus
Shunts blood from umbilical vein to IVC, bypassing liver
Ductus arteriosus
Goes from pulm. artery to aorta, bypassing lungs
Foramen Ovale
Shunt from right atria to left atria
Titin connects which 2 parts of the sarcomere?
Z-line to M-line
How does vagal nerve activity affect heart?
(1) increased special conduction and atrial K+ permeability
(2) Inhibits funny channels
(3) Inhibits slow Ca current
Rheumatic fever can cause
Mitral stenosis
