exam 1 lecture 7

Question 1

hyperemia

Answer 1

oxygen deficiency, vasodilation, carbon dioxide, hydogen ions, lactic acid account for

Question 2

active hyperemia

Answer 2

skeletal muscle, heart and cerebral and splanchnic circulations, blood flow increases with increases metabolic activity. Because of accumulation of vasodilators coupled with initial reduce oxygen tension and nutrient supply

Question 3

reactive hyperemia

Answer 3

when blood supply to tissue is clamped and then restored, flow through tissue increase by as much as five fold times, accumulation of vasodilators, reduced oxygen tension and depletion of nutrients (BUT can also lead to hypoxic pulmonary vasoconstriction)

Question 4

autoregulation

Answer 4

when tissues maintain a fairly constant blood flow over a perfusion pressures ranging from 70-175 mmHg. Manly in renal, cerebral and coronary circuits

Question 5

explanations for autoregulation

Answer 5

flushing vasodilators metabolites out of tissue when flow increases causes vasoconstriction and increase in R, myogenic mechanism: bayliss hypothesis, sudden stretch of the vessels walls provoke arterial and arteriolar smooth muscle to contract, causing vasoconstriction-> decrease flow

Question 6

fast myogenic response is 50% responsible for renal blood flow autoregulation how?

Answer 6

Tubuloglomerular feedback (NaCl, macula densa, extraglomerular mesangial cells and afferent arterioles) complements the myogenic response.

Question 7

vasoconstrictors

Answer 7

THE CATECHOLAMINES: Norepinephrine and epinephrine bind β1 adrenergic receptors in the heart,, alpha1 adrenergic receptors in the smooth muscle cells of the media of most blood vessels.Low E concentrations= vasodilator (beta 2)
high E concentrations= vasoconstrictor (alpha 1)

Question 8

Dopamine

Answer 8

vasoconstrictor: Vasodilator at low concentrations (dopamine receptors), vasoconstrictor at high concentrations
(alpha1 adrenergic receptors). Acts on the heart at moderate doses (β1 adrenergic receptors )

Question 9

dobutamine

Answer 9

sysnthetic catcholamine primarily with beta 1 activity, inotropic support in cardiogenic shock

Question 10

Angiotensin II

Answer 10

Octapeptide, amount in the circulation controlled
by renin secreted by the JG cells
Low concentrations= Constricts the renal arteries and stimulates adrenal cortex to secrete aldosterone
High concentrations: Generalized vasoconstriction

Question 11

angiotensin II blockers

Answer 11

ACE inhibitors used for anti-hypertensive therapies

Question 12

ADH, or vasopressin

Answer 12

increased water permeability in collecting ducts of kidney, high concentrations= vasoconstictor.

Question 13

ADH release when

Answer 13

high osmotic pressure, reduced blood volume, and reduced MAP

Question 14

thromboxane A2

Answer 14

prostaglandin vasoconstrictor, causes platelet aggregation and vasoconstriction

Question 15

endothelin

Answer 15

ET-1 split from ET-1 by endothelin converting enzyme, long lasting vasoconstrictor

Question 16

Beta 2 adrenergic receptors

Answer 16

vasodilation when bind E

Question 17

Bradykinin

Answer 17

A nonapeptide that acts by stimulating nitric oxide and prostacyclin formation by the vascular endothelium.
Involved in inflammation
Destroyed by angiotensin-converting enzyme

Question 18

serotonin

Answer 18

In platelet granules.
Concentration can increase locally after platelet activation.
Effects complex, depending on dose, experimental conditions, animal species and vascular state.

Question 19

histamine

Answer 19

Can be a powerful dilator of arterioles, except in the lungs,where it increases PVR
Increases capillary permeability (e.g. to proteins)
Important in inflammation and anaphylactic shock,
where it is released by mast cells.

Question 20

prostacyclin

Answer 20

produced by the vascular endothelium by prostacyclin synthase used to treat PHT
antagonistic to thromboxane A2

Question 21

NO

Answer 21

Apart from its action on the vasculature, it also inhibits platelet adhesion, NO is continually produced by nitric oxide synthase in the vascular endothelium,

Question 22

vascular endothelium source of

Answer 22

prostacyclin (vd), NO (vd) and endothelin (vc)

Question 23

Parasympathetics

Answer 23

Heart (mainly rate)
Blood vessels: vasodilation in the blush areas and genitals (penile erection is via the intermediary nitric oxide).

Question 24

sympathetic branch

Answer 24

Controls distribution of cardiac output by vasoconstriction, mainly in the splanchnic and cutaneous circulations.
Regulates mean arterial pressure by acting on the:
a. Heart (cardiac output) (beta 1)
b. Blood vessels (SVR,
capacity) (alpha 1)
c.Volume, via the kidneys
(affects cardiac output)

Question 25

Angiogenesis

Answer 25

formation of new blood vessels: ischemic tissue, hypoxic wounds, embryogenesis, menstrual cycle.

Question 26

unregulated angiogenesis

Answer 26

tumor growth, arthritis, diabetic retinopathy, retinopathy of prematurity.

Question 27

endogenous angiogenesis inhibitors

Answer 27

prevent corneal neovascularization.

Question 28

angiogenic factors

Answer 28

Synthesis and release of angiogenic factors is driven by low oxygen – high oxygen suppresses them.

Question 29

MAP regulated by sympathetics (raise MAP)

Answer 29

cardiac output (beta 1), total peripheral resistance (arterioles, alpha 1), capacity (veins and venules alpha 1) and blood volume (renin-angiotensin II-ADH)

Question 30

baroreceptor reflex (volume depletion)

Answer 30

activator of sympathetic nervous system. critical for blood pressure homeostasis.Stretch receptors in the carotid sinuses (less importantly the aortic arch) communicate via Hering’s nerve (branch of IX) with neurons in the nucleus tractus solitarius. NTS is the integrating hub, and modulates the activity of sympathetic and parasympathetic (vagal) neurons in the medulla.

Question 31

baroreceptor reflex protect against

Answer 31

FALL in MAP, does provide against protection for hypertension

Question 32

when blood pressure rises....?

Answer 32

impulses from baroreceptor increases in frequency, reducing sympathetic vasoconstriction tone

Question 33

when blood pressure decreases?

Answer 33

baroreceptor reduce their firing rate , increasing vasomotor tone and causes constriction of veins and arterioles

Question 34

Shy-Drager

Answer 34

Multiple system atrophy with orthostatic hypotension.A progressive disorder of the CNS and ANS for which there is no cure. Orthostatic hypotension is the first sign of autonomic system failure

Question 35

orthostatic hypotention patient

Answer 35

supine: 120/74, sitting: 98/54, standing: 84/48

Question 36

Bainbridge reflex (volume loading)

Answer 36

sometimes called the atrial reflex, is an increase in heart rate and renal vasodilation due to an increase in central venous pressure operating on receptors located on the low pressure side of the circulation.

Question 37

atrial natriuretic peptide

Answer 37

secretion caused from atrial distension from increased venous pressure. inhibits ADH, renin and aldosterone secretion

Question 38

renin-aldosteron-angiotensin system

Answer 38

Most important action to control plasma volume. Takes several hours for pathophysiological expression, as might occur in the setting of hemorrhage or MI Antidiuretic, vasoconstriction

Question 39

aldosterone

Answer 39

prevents sodium from excretion by promoting sodium reabsorption in distal and collecting tubules of kidneys, causes water retention in response to reduced systemic arterial pressure