Cardiovascular system compensation Flashcards
(37 cards)
What role does innervation of the heart play
- it modulates the output so the nerves can change contractility and heart rate
What type of nerves supply the heart?
autonomic nerves
How can the sympathetic nervous system best be defined?
What affect does this have on the heart?
Fight flight or freeze
Inc contractility and HR
How is the parasympathetic nervous system described. What affect does this have on the heart?
Rest and digest
Decrease in contractility and HR
What affect does the sympathetic nervous system have on blood vessels?
Vasoconstrict to non essential organs: GI tract, Reproductive tract, Skin, kidney (everything else)
Vasodilation to essential organs: working skeletal muscle, heart (also brain)
What is the origin and exit of the sympathetic sympathetic nervous system?
Both originate in CNS but exit different:
1. Sympathetic nerves exit from spinal cord: Thoracolumbnar segments: only thoracic and lumbar portions of spinal cord: T1- L2
Talk about sympathetic nervous system and ganglion
Short PRE ganglionic fibres that travel to a ganglion and synapse with a post ganglionic fibre
What is the sympathetic supply to the heart?
From the sympathetic ganglia C5 - T3
NOT THE SAME AS SPINAL C5 and T3!!!!
Where is the anatomical origin of the parasympathetic nervous system
- Craniosacrel origin
Because the preganglionic fibres from para exit from either cranial nerves in brain stem or sacral spinal segments.
Cranial nerves are 3, 7, 9, 10 (vagus nerve which supplies the throacic viscera)
Which vessels are most responsible for altering blood flow to a tissue in the systemic circulation
- Arterioles
What effect will a generalised vasodilation have on cardiac output and why?
What if just arteriole dilation
First = most common
1. decrease preload as making vessels wider:. reduce hydrostatic pressure:. reduce pressure leading into heart
2. Reduced preload reduces cardiac output as reduces EDVV:. reduced V filling:. reduces SV
CO = SV X HR
ALSOOOOO
1. arteriole dilation = decreased afterload = inc CO
2. because dec AL = reduced ESVV as bigger pressure gradient (pressure in arteries is lower than the pressure V generates so more blood moves out = less left in V at end of Systole)
therefore higher ejection fraction, higher SV, higher CO
What effect will a generalised vasoconstriction have on cardiac output and why?
- inc CO as inc preload as dec size of container = inc Hydrostatic pressure = inc pressure supplying V
- Decrease CO as inc afterload = reduced ventricular emptying - less blood moves out.
What BV does the parasympathetic nervous system innovate?
ONLY genital and coronary, other effects on BV is due to lack of sympathetic stimulation rather than direct parasympathetic effect”
What receptors do the blood vessels that are innovated by the parasympathetic nervous system have?
M3 CHOLINERGIC
What heart receptor is associated with the para
M2 CHOLINERGIC
What receptors do the blood vessels have that are innovated by the sympathetic nervous system
alpha 1, 2, Beta 2 adrenergic receptors
Also M3 CHOLINERGIC
What receptors does the heart have that is innovated by the sympathetic nervous system?
beta 1 adrenergic on cardiac myocytes and nodal tissue
What is nodal tissue?
a unique type of tissue that has both muscular adn nervous characteristics adn can be found at the SAN and AVN. Responsible for coordinating the cardiac cycle
What are the 5 systems that manage BP during exercise
- Metabolic autoregulation of blood flow
- Psychogenic response
- Exercise reflex
- Baroreflex
- Skeletal muscle and Respiratory pumps
How deos the psychogenic response affect the body
- Inc sympathetic activity, dec para
- inc CO: inc HR, contractility, conduction speed
- Increased TPR (total pulmonary resistance): vasoconstriction of non-essential organs, inc preload
- inc blood pressure
- this is a graded response and continues throughout exercise, changing degree
What is the exercise reflex?
- mechanical- to do with activity of joint and muscle by receptors which tell train how hard you are working
- Modifies the degree of autonomic activity
- feedback system
What is the respiratory pump?
- increase depth and rate of breathing helps pump blood due to physical expansion adn contraction of chest = squishes and stretches vessels in chest = inc preload
What is the skeletal pump
- veins squashed more = emptying veins = push blood back to heart = fill more readily = inc preload
What is the baroreflex?
- monitors blood pressure
