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ADV. Human Phys > Test 4 Study Guide Part 3 > Flashcards

Test 4 Study Guide Part 3 Flashcards

1
Q

The heart normally runs aerobically or anaerobically?

A

aerobically

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2
Q

What helps to enable the heart to run aerobically?

A
  • High density of capillaries
  • Myoglobin (collects oxygen during diastole, releases it during systole)
  • High number of mitochondria
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3
Q

Epinephrine and Norepinephrine regulation of the heart:

A

Epinephrine causes vasodilation of the heart (fight or flight)
Norepinephrine causes vasoconstriction of the heart (at rest)

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4
Q

What is the primary cause of vasodilation in the heart?

A

Intrinsic metabolic vasodilation:

- metabolic auto regulation of the heart in response to increased build up of metabolites

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5
Q

Dynamic exercise:

Static exercise:

A

Dynamic exercise:
Exercise involving movement
Static exercise:
Exercise involving little to no movement (wall sit is an example)

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6
Q

Resistance of blood flow to muscle increases or decreases?
Dynamic exercise:
Static exercise:

A

Dynamic exercise:
Decreases (more blood flow)
Static exercise:
Increases (less blood flow)

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7
Q

Dynamic exercise increases blood flow because:

A
  • Increased to blood flow (increased cardiac output)
  • Metabolic vasodilation of exercising muscles
  • Diversion of blood away from viscera and skin
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8
Q

Breathing and pulse rate increase within one second of exercise, why?

A

Motor cortex effects heart rate and respiration rate
Sensory feedback of contracting muscles increases it
Baroreceptor reflex causes stronger contraction

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9
Q

Blood flow to the brain:

  • Is normally kept _____:
  • Light to moderate exercise:
  • Heavy exercise:
A
  • Is normally kept _____:
    constant
  • Light to moderate exercise:
    Increases slightly, likely due to increased vasodilation of motor cortex from metabolic regulation of blood vessels.
  • Heavy exercise:
    Decreases, likely because high ventilation lowers body CO2, producing cerebral vasoconstriction
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10
Q

Cardiac output can increase to 5 times as strong in an untrained athlete due to?

A

High increase in heart rate.

Moderate increase in stroke volume.

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11
Q

Cardiac output can increase to 6 to 7 times as strong in an TRAINED athlete due to?

A

High increase in heart rate.

High increase in stroke volume.

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12
Q

Vo2 stands for?

A

Maximal Oxygen Uptake

Greatly increased in athletes due to increased stroke volume

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13
Q

Why does increased heart rate not result in decreased end-diastolic volume?

A

Increased venous return from skeletal muscle contraction

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14
Q

Ejection fraction:

  • Define:
  • Change during exercise:
A
  • Define:
    Percentage of end diastolic volume which is excreted
  • Change during exercise:
    Increases from 60% -> 90%
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15
Q

Why do trained athletes have lower resting cardiac rate?

A

higher stroke volume due to an increase in blood volume

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16
Q

Skin:

  • Regulation is predominately:
  • Consistency of blood flow:
A
  • Regulation is predominately:
    Extrinsic mechanism
  • Consistency of blood flow:
    more variation than any other organ, highly tolerant
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17
Q

What is the blood flow of the brain maintained at?

Regardless of cardiac output.
What must the brain do in response to exercise and increased cardiac output?

Implication for distribution of resources in brain?

A

750 ml/min
Vasoconstrict
Brain must choose where it gives blood to, and where it will in turn take blood from.

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18
Q

Low CO2 causes cerebral vasoconstriction:

  • Mechanism:
  • Term for this type of regulation:
A
  • Mechanism:
    Vessels in brain sense levels of CO2 levels (actually caused by sensing pH in Cerebral spinal fluid), increased CO2 results in vasodilation, decreased CO2 results in vasoconstriction
  • Term for this type of regulation:
    Metabolic regulation
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19
Q

Blood flow to the brain is constant. What mechanism does the brain use to control where it sends blood given it has a set amount regardless of workload?

A

Intrinsic metabolic vasodilation (if you are being used, you build up metabolites, and vasodilate)

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20
Q

Positron emission topography:

  • How it works:
  • What is it a proxy for?
A
  • How it works:
    Radioactive isotope injected into blood
    Gives of positrons at a set rate
    High levels of positrons will be high levels of blood flow
  • What is it a proxy for?
    Blood flow goes to the region being used.
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21
Q

How can neurons directly signal that they need more blood?

A

They can increase vasodilator chemicals like:

- K+, adenosine, Nitric Oxide (NO) and others

22
Q

How can astrocytes be used by neurons to increase vasodilation?

A

Neurons can stimulate astrocytes with glutamate, causing them to secrete vasodilator like…
CO and prostaglandin E2

23
Q

How might stimulation by active neurons and astrocytes effect endothelial cells?

A

Promote them to release NO-, which in turn promotes vasodilation

24
Q

Increased blood flow to a region in response to activity (necessity)

A

Functional Hyperemia:

25
Q

Neurovascular coupling:

A

Refers to stimulation of astrocytes by production of glutamate (as well as release of vasodilators directly).
Astrocyte production of CO and prostaglandin E2
Endothelial cells responding to astrocyte and neuron secretions to produce increased NO and cause even more vasodilation

26
Q

How does my body cool its blood?

A

It opens arteries leading to the skin (vasodilation)

It also closes deep arteriovenous anastomoses which divert blood away from the capillary loops and into the depths!

27
Q

Capillary loops:

(arteriovenous anastomoses) Deep Venous shunts:

A

Allow blood to flow close to the surface of skin, cooling it

Allow blood to bypass the capillary loops (when vasodilated) and avoid the surface of the skin

28
Q

arteriovenous anastomoses are located predominately where?

A

Fingertips, palms of hand, soles of feet, toes, ears, nose, lips.
- Places which are extremities of the body, or contact the ground, which will be given up on if it gets too cold

29
Q

Why doe cheeks appear rosy despite vasoconstriction?

A

Vasoconstriction arteriovenous anastomoses causes a net decrease in rate of blood flow, but does shift what blood there is to the surface of the vein

30
Q

Why is frost bite damage irreversible?

A

Ice crystals form in skin, when they thaw they lyse the plasma membrane.

31
Q

How much does blood flow to the skin vary?

A

from 20 ml / minute to 3-4 L / minute

32
Q

What is responsible for vasodilation in responsible to high internal temperature?

A

Decreased sympathetic innervation (sympathetic innervation vasoconstriction the cutaneous arteries)

33
Q

Sweat glands have two action to help cooling, what are they?

A
  • Excrete bradykinin, a vasodilator

- Excrete water to evaporate

34
Q

How does the body lower temperature during fight or flight induced exercise despite initial vascular constriction in skin?

A

It later vasodilates

35
Q

What maintains arterial blood pressure during exercise when both muscles and skin to have vasodilated?

A

The increased cardiac output of the heart

36
Q

What happens if you stop exercising but your skin does not cool down (because it is very humid, or you are wearing a coat?)

A

The skin is still intaking large amounts of blood to cool the body.
As your cardiac rate drops, if the blood is not cooled, arterial resistance will also drop, as blood can easily go into the skin

37
Q

Why do cold sweats occur?

Why does blushing occur?

A

Sweating and vasodilation is controlled by the sympathetic nervous system, which is controlled by the brain.
The brain can cause these effects regardless of temperature

38
Q

What is an advantage of the slow flow of blood through the capillaries?

A

Increased time for diffusion of nutrients

39
Q

Why does blood pressure slow when you get to the capillaries?

A

They have the greatest cross sectional area (it’s as if the pipe got a larger diameter, flow slows, pressure drops)

40
Q

What are the most important variables effecting blood pressure?

A
  • Stroke volume (determined by blood volume)
  • Afterload (arterial resistance) arteries must have a small cross sectional area
  • Cardiac output
41
Q

Sphygmomanometer:
Manometer:

A

Measures blood pressure

Measures blood pressure inside of cuff

42
Q

What organ predominately regulates blood pressure?

A

the kidney

43
Q

Baroreceptors:

  • Two locations:
  • How do they work:
  • More sensitive to increases or decreases in blood pressure?
A
  • Two locations:
    Aortic arch
    Carotid Sinuses
  • How do they work:
    Stretch receptors. increased pressure -> increase firing -> signal to vasomotor control center and cardiac control center
  • More sensitive to increases or decreases in blood pressure?
    Increases
44
Q

Location and function:

  • Vasomotor Control Center:
  • Cardiac Control Center:
A 
- Vasomotor Control Center:
Medulla oblongata
Controls vasoconstriction vs vadoilation
- Cardiac Control Center:
Medulla oblongata
regulates heart rate
45
Q

Baroreceptor Reflex:

A

Aortic arch/carotid sinus -> vasomotor and cardia control center -> parasympathetic and sympathetic axons -> heart and blood vessel effectors

46
Q

How does control by the Baroreceptor Reflex differ from kidney control of blood pressure?

A
  • Baroreceptor: controls on a beat by beat basis

- Kidney: controls longterm regulation of blood pressure (by changing blood volume)

47
Q

Standing up will cause a blood pressure change countered how?

A

Blood flows into veins in legs. Blood pressure falls.
Vasoconstriction.
Heart increases rate of beating

48
Q

Massaging of carotid sinus, or karate chopping it, results in what?

A

Increase in detected blood pressure

Vasodilation, lowered heart rate, fall in blood pressure

49
Q

Korotkoff method:

  • Other name:
  • What is it?
A

Auscilatory method

Taking blood pressure with a sphygmometer

50
Q

Source of sound throughout blood pressure test:

  • Drive blood pressure cuff up high:
  • First Korotkoff sound:
  • low muffled rushing sound:
  • Last Korotkoff sound (sound above stops):
A
  • Cuff pressure is high, no sound:
    no flow of blood through artery
  • First Korotkoff sound (first sound) soft tapping sound:
    Blood artery opening and closing as the heart seizes, systolic pressure
  • low muffled rushing sound:
    Arteries compressed, turbulent flow
  • Last Korotkoff sound (sound above stops):
    Artery is no unrestricted, blood flow is normal, no sound, diastolic pressure
51
Q

Co2 is a powerful (vasodilator/vasoconstrictor):

This is what type of control?

A

Vasodilator

Metabolic autonomic vasodilation

52
Q

How can levels of blood flow in the brain be measured

A

Positron emission topography

ADV. Human Phys (51 decks)

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