Test 4 Study Guide Part 3

Question 1

The heart normally runs aerobically or anaerobically?

Answer 1

aerobically

Question 2

What helps to enable the heart to run aerobically?

Answer 2

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

Question 3

Epinephrine and Norepinephrine regulation of the heart:

Answer 3

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

Question 4

What is the primary cause of vasodilation in the heart?

Answer 4

Intrinsic metabolic vasodilation:

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

Question 5

Dynamic exercise:

Static exercise:

Answer 5

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

Question 6

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

Answer 6

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

Question 7

Dynamic exercise increases blood flow because:

Answer 7

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

Question 8

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

Answer 8

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

Question 9

Blood flow to the brain:

• Is normally kept _____:
• Light to moderate exercise:
• Heavy exercise:

Answer 9

• 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

Question 10

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

Answer 10

High increase in heart rate.

Moderate increase in stroke volume.

Question 11

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

Answer 11

High increase in heart rate.

High increase in stroke volume.

Question 12

Vo2 stands for?

Answer 12

Maximal Oxygen Uptake

Greatly increased in athletes due to increased stroke volume

Question 13

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

Answer 13

Increased venous return from skeletal muscle contraction

Question 14

Ejection fraction:

• Define:
• Change during exercise:

Answer 14

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

Question 15

Why do trained athletes have lower resting cardiac rate?

Answer 15

higher stroke volume due to an increase in blood volume

Question 16

Skin:

• Regulation is predominately:
• Consistency of blood flow:

Answer 16

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

Question 17

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?

Answer 17

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

Question 18

Low CO2 causes cerebral vasoconstriction:

• Mechanism:
• Term for this type of regulation:

Answer 18

• 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

Question 19

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?

Answer 19

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

Question 20

Positron emission topography:

• How it works:
• What is it a proxy for?

Answer 20

• 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.

Question 21

How can neurons directly signal that they need more blood?

Answer 21

They can increase vasodilator chemicals like:

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

Question 22

How can astrocytes be used by neurons to increase vasodilation?

Answer 22

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

Question 23

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

Answer 23

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

Question 24

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

Answer 24

Functional Hyperemia:

Question 25

Neurovascular coupling:

Answer 25

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

Question 26

How does my body cool its blood?

Answer 26

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!

Question 27

Capillary loops: | (arteriovenous anastomoses) Deep Venous shunts:

Answer 27

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

Question 28

arteriovenous anastomoses are located predominately where?

Answer 28

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

Question 29

Why doe cheeks appear rosy despite vasoconstriction?

Answer 29

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

Question 30

Why is frost bite damage irreversible?

Answer 30

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

Question 31

How much does blood flow to the skin vary?

Answer 31

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

Question 32

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

Answer 32

Decreased sympathetic innervation (sympathetic innervation vasoconstriction the cutaneous arteries)

Question 33

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

Answer 33

- Excrete bradykinin, a vasodilator | - Excrete water to evaporate

Question 34

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

Answer 34

It later vasodilates

Question 35

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

Answer 35

The increased cardiac output of the heart

Question 36

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

Answer 36

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

Question 37

Why do cold sweats occur? | Why does blushing occur?

Answer 37

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

Question 38

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

Answer 38

Increased time for diffusion of nutrients

Question 39

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

Answer 39

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

Question 40

What are the most important variables effecting blood pressure?

Answer 40

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

Question 41

Sphygmomanometer: Manometer:

Answer 41

Measures blood pressure | Measures blood pressure inside of cuff

Question 42

What organ predominately regulates blood pressure?

Answer 42

the kidney

Question 43

Baroreceptors: - Two locations: - How do they work: - More sensitive to increases or decreases in blood pressure?

Answer 43

- 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

Question 44

Location and function: - Vasomotor Control Center: - Cardiac Control Center:

Answer 44

``` - Vasomotor Control Center: Medulla oblongata Controls vasoconstriction vs vadoilation - Cardiac Control Center: Medulla oblongata regulates heart rate ```

Question 45

Baroreceptor Reflex:

Answer 45

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

Question 46

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

Answer 46

- Baroreceptor: controls on a beat by beat basis | - Kidney: controls longterm regulation of blood pressure (by changing blood volume)

Question 47

Standing up will cause a blood pressure change countered how?

Answer 47

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

Question 48

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

Answer 48

Increase in detected blood pressure | Vasodilation, lowered heart rate, fall in blood pressure

Question 49

Korotkoff method: - Other name: - What is it?

Answer 49

Auscilatory method | Taking blood pressure with a sphygmometer

Question 50

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):

Answer 50

- 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

Question 51

Co2 is a powerful (vasodilator/vasoconstrictor): | This is what type of control?

Answer 51

Vasodilator | Metabolic autonomic vasodilation

Question 52

How can levels of blood flow in the brain be measured

Answer 52

Positron emission topography