Hemodynamic Defense Response

Question 1

what is the main goal of the hemodynamic defense?

Answer 1

maintain cardiovascular integrity

Question 2

what are the key systems involved in blood pressure control?

Answer 2

baroreceptor reflexes
sympathetic nervous system
renin angiotensin aldosterone system
antidiuretic hormone

Question 3

what is the equation for cardiac output?

Answer 3

CO= stroke volume x heart rate

Question 4

what is the equation for mean arterial pressure?

Answer 4

MAP= diastolic blood pressure + 1/3 of pulse pressure

Question 5

what happens with mean arterial pressure during exercise?

Answer 5

it stays the same

Question 6

what vessels determine peripheral vascular resistance?

Answer 6

arterioles

Question 7

what is the major determinant of resistance?

Answer 7

radius of the vessel

Question 8

what performs short term blood pressure control?

Answer 8

vasomotor center
baroreflexes and autonomic control

Question 9

where is the vasomotor center located?

Answer 9

reticular substance of the medulla and lower pons

Question 10

what is the sensory area of the vasomotor center?

Answer 10

nucleus solitarius

Question 11

how does the vasodilator area of the vasomotor center perform?

Answer 11

inhibit vasoconstrictor activity with its fibers

Question 12

where are high pressure baroreceptors located?

Answer 12

carotid sinus and aortic arch

Question 13

what is the first line of defense to acute changes in blood pressure?

Answer 13

high pressure baroreceptors in carotid sinus and aortic arch

Question 14

where are low pressure baroreceptors located?

Answer 14

large intrathoracic vessels and the heart

Question 15

what is the stimulus for the low pressure baroreceptors?

Answer 15

increased stretch

Question 16

what is the bainbridge reflex?

Answer 16

increased sympathetic outflow detected by low pressure baroreceptors (increased stretch) leads to an increase in heart rate

Question 17

what are the specific responses to acute hypotension?

Answer 17

vasomotor center receives input from baroreceptor via cranial nerves IX and X: vasomotor center
nucleus solitarius conveys signal to vasoconstrictor and vasodilator centers
increased sympathetic activity: vasoconstriction, increased heart rate and contractility

Question 18

what is the general response to acute hypotension?

Answer 18

increased cardiac output
restoration of normal blood pressure

Question 19

what serves as the intermediate control of blood pressure?

Answer 19

epinephrine and norepinephrine

Question 20

what are alpha1 receptors chiefly mediated by?

Answer 20

norepinephrine

Question 21

what are beta1 receptors chiefly mediated by?

Answer 21

epinephrine

Question 22

what is the net result of beta1 receptors being stimulated?

Answer 22

increased cardiac output

Question 23

what type of blood pressure control does the renin angiotensin aldosterone system provide?

Answer 23

intermediate to long term

Question 24

what are the causes of renin release?

Answer 24

renal sympathetic stimulation
decreased renal perfusion
decreased sodium delivery to the macula densa

Question 25

what organ releases and produces renin?

Answer 25

kidney

Question 26

where is angiotensinogen made?

Answer 26

liver

Question 27

how do renin and angiotensinogen interact?

Answer 27

renin acts on angiotensinogen to make angiotensin-I (AT-I)

Question 28

how is angiotensin-I converted into angiotensin-II (AT-II)?

Answer 28

angiotensin converting enzyme (ACE)

Question 29

what are some stimuli of aldosterone?

Answer 29

angiotensin II decreased sodium load at the macula densa increased potassium ACTH

Question 30

why is antidiuretic hormone primarily released?

Answer 30

plasma hyperosmolarity (dehydration)

Question 31

when is antidiuretic hormone inappropriately elevated?

Answer 31

in CHF

Question 32

what is the response to antidiuretic hormone?

Answer 32

direct vasoconstriction increased permeability to water in the distal tubule

Question 33

what are the two natriuretic peptides?

Answer 33

atrial and brain natriuretic peptides

Question 34

what stimulates the release of the natriuretic peptides?

Answer 34

stretch of the atria or ventricles myocardial dysfunction

Question 35

how are the natriuretic peptides activated?

Answer 35

proteolytic cleavage

Question 36

what maintains cardiovascular integrity in the short term?

Answer 36

autonomic nervous system

Question 37

what maintains cardiovascular integrity in the long term?

Answer 37

salt and water retention

Question 38

what maintains cardiovascular integrity in the intermediate term?

Answer 38

humoral factors

Question 39

what is the first line defense against rapid changes in blood pressure?

Answer 39

baroreceptor reflexes

Question 40

how does the sympathetic nervous system control blood pressure?

Answer 40

rapid selective vasoconstriction and increased cardiac output

Question 41

what timeline does the renin angiotensin aldosteron system work over?

Answer 41

intermediate and long term

Question 42

how is peripheral vascular resistance decreased in exercise?

Answer 42

arteriolar vasodilation in skeletal muscle

Question 43

what is poiseuille's law?

Answer 43

R=8nL/(pi x r^4)

Question 44

what controls peripheral vascular resistance acutely?

Answer 44

autonomic control: baroreceptors metabolic, paracrine factors

Question 45

what controls peripheral vascular resistance in intermediate and long-term?

Answer 45

sympathetic nervous system angiotensin vasopressin endothelin

Question 46

what does the vasomotor center transmit?

Answer 46

parasympathetic impulses through vagus to heart sympathetic impulses through spinal cord and sympathetic nerves to vasculature and heart

Question 47

what does the vasoconstrictor area of the vasomotor center do?

Answer 47

distributes fibers to cord: excited vasoconstrictor neurons of sympathetic nervous system

Question 48

what do high pressure baroreceptors detect?

Answer 48

magnitude, rate of change of pressure-induced stretch of arterial wall

Question 49

what is the response to increased stretch in the low pressure baroreceptors?

Answer 49

bainbridge reflex decreased renin and AVP release: increase Na and H2O excretion

Question 50

what is the pathway for secretion of epinephrine and norepinephrine?

Answer 50

adrenal medullary secretion of both epi: alpha and beta norepi: alpha

Question 51

what is the stimulus to release epinephrine and norepinephrine?

Answer 51

generalized sympathetic nervous system stimulation

Question 52

what does alpha1 stimulation by norepinephrine lead to?

Answer 52

increased peripheral vascular resistance and venous return to heart arteriolar vasoconstriction venous vasocnstriction

Question 53

what does beta1 stimulation by epinephrine lead to?

Answer 53

increased chronotropy, inotropy, and lusitropy (relaxation): increased cardiac output

Question 54

what is the response to angiotensin II?

Answer 54

vasoconstriction, thirst kidney: conserve Na and H2O, efferent arteriolar vasoconstriction aldosterone and ADH release

Question 55

how does aldosterone work?

Answer 55

transcription of Na/K pumps in distal convoluted tubule increased number of Na channels increased potassium secretion into tubules

Question 56

what is the response to aldosterone?

Answer 56

sodium and water retention, potassium excretion myocardial remodeling and fibrosis

Question 57

why is antidiuretic hormone released?

Answer 57

primary: plasma hyperosmolarity also: decreased atrial stretch, angiotensin II, decreased arterial stretch

Question 58

what is the response to antidiuretic hormone?

Answer 58

direct vasoconstriction increased permeability to water in distal tubule

Question 59

what do the intra-cardiac RAAS systems drive?

Answer 59

remodeling progressive hypertrophy fibrosis

Question 60

what do the atrial and brain natriuretic peptides do?

Answer 60

diuretic effect endogenous antagonists to RAAS inhibit sympathetic nervous system and vasopressin

Question 61

what do the natriuretic peptides do to blood pressure?

Answer 61

decrease it