circulatory system part 4

Question 1

Cardiac output is what?

equation?

Answer 1

Volume of blood pumped per unit time

CO=HRxSV

rate of contraction (beats per minute)

s

Question 2

What is stroke volume?

Answer 2

volume of blood pumped with each beat

stroke volume= end diastolic volume- ensystolic volume

Question 3

how can cardiac output be modified?

Answer 3

by regulating heart rate and/or stroke volume (chronotropy, inotropy

Question 4

What is heart rate modulated by?

Answer 4

autonomic nerves and adrenal medulla

Question 5

What is stroke volume modulated by?

Answer 5

various nervous, hormonal, and physical factors

Question 6

Effects of norepinephrine on cardiomyocytes?

Answer 6

nervous and endocrine systems can cause the heart to contract more forcefully and pump more blod with each beat

Question 7

Control of stroke volume:

what is the Frank-Starling effect?

Answer 7

increase end-diastolic volume results in a more forceful contraction and increase SV

length-tension relationship for muscles

heart automatically compensates for increase in volume of blood returning to the heart

Question 8

Control of stroke volume:

Level of sympathetic activity shifts what?

Answer 8

the position of the cardiac muscle length-tension realationship

Question 9

Regulation of blood flow:

Law of bulk flow: Q= delta P/R

what are the variables?

Answer 9

Q= flow
Delta P= pressure drop
R= resistance

Question 10

Regulation of blood flow:

Poiseuille’s equation:

Q=delta P x Pie x r ^2/ 8Ln

Answer 10

L = length
n= viscosity of fluid
r= radius

Question 11

Regulation of blood flow:

what is the primary driving force of blood through organs?

Answer 11

pressure

Question 12

Regulation of blood flow:

what is Vasoconstriction and Vasodilation?

Answer 12

small changes in radius - large changes in resistance and flow

Question 13

Regulation of blood pressure:

How does the body maintain a near constant mean arterial pressure? (MAP)

Answer 13

Body varies cardiac output (CO)

and total peripheral resistance (TPR)

Question 14

Regulation of blood flow:

Arterioles control blood distribution how?

Answer 14

because arterioles are arranged in parallel, they can alter blood flow to various organs

• vasocanstrication and diolation

changes in resistance alter flow

Question 15

Regulation of blood flow:

How does the body control vasoconstriction and vasodilation?

Answer 15

autoregulation:
-direct response of the artiole smooth muscle

Intrinsic factors:
- metabolic state of the tissue

Extrinsic factors:
-Nervous and endocrine system

Question 16

Metabolic activity of tissues:

Smooth muscle cells in arterioles are senstivie to what?

Answer 16

conditions of extracellular fluid

Question 17

Metabolic activity of tissues:

levels of metabolities alter what?

Answer 17

vasoconstriction and vasodilation

Question 18

Metabolic activity of tissues:

Bloodflow is matched to what?

Answer 18

metabolic requirements

Question 19

Metabolic activity of tissues:

Exercise - decrease o2 increase co2 causes what?

Answer 19

vasodilation

Question 20

Metabolic activity of tissues:

Paracrine- nitric oxide casues what?

Answer 20

vasodilation

Question 21

Neural and endocrine control of flow:

Nerepinephrine from sympathetic neurons cause what>

Answer 21

Vasoconstriction of arteriols

Question 22

decrease in sympathetic tone causes what?

Answer 22

Vasodilation

Question 23

What are the other hormones what affect vascular smooth muscles?

Vasopressin (ADH) causes what?

Answer 23

from posterior pituitary causes general vascoconstriction

Question 24

What are the other hormones what affect vascular smooth muscles?

Angiotension 2

Answer 24

Produced in response to decreased blood pressure causes generalized vasoconstriction

Question 25

What are the other hormones what affect vascular smooth muscles?

atrial natriuretic peptide (ANP)

Answer 25

produced in response to increase blood pressure promotes generalized vasodilation

Question 26

Baroreceptor reflex:

what are these and where are they?

Answer 26

strtch-sensitive mechano-receptors are in walls of many blood vessels

especially carotid arteries and aorta

send nerve signals to medulla

They regulate MAP

(Spock pinch?)

Question 27

What is spock pinch

Answer 27

our nerdy teacher wants us to relate this to star trek

he pinches the baroreceptors and decreases blood flow causes them to pass out