Blood Pressure Regulation

Question 1

Maintaining blood pressure: Short-term regulation

Answer 1

Neural controls: alter CO and R (resistance) to adjust for short-term BP fluctuations

Location: nervous system

Question 2

1. Baroreceptors: pressure receptors

Answer 2

These report to the medula oblengota when:

a. When hypertensive, baroreceptors are: stimulated or triggered

b. Cardiac center responds by: performing cardioinhibition (when we need to raise our BP -> Stimulated)

c. Vasomotor center responds by: inhibited to allow vasodilation. Resistance goes down and BP goes down.

d. Results: lowers HR, low R = lower BP = back to normal

e. Opposite events take place when hypotensive.

Question 3

2. Chemoreceptors: chemical receptors located close to baroreceptors.

Answer 3

a. Chemoreceptors detect the following:

i. Hypercapina (elevated CO2)

ii. Acidosis (low pH)

iii. Hypoxia

Question 4

2. Chemoreceptors: chemical receptors located close to baroreceptors.

Answer 4

b. Under these chemical conditions, the chemoreceptors will: activate cardiac center to perform cardioacceleration, trigger vasomotor center for vasoconstriction which makes R go up thus increasing our HR.

Question 5

2. Chemoreceptors: chemical receptors located close to baroreceptors.

Answer 5

c. Chemoreceptors stimulate an increase in BP to push more blood to the pulmonary circuit. To allow the gas exchange to go into lungs.

Question 6

2. Chemoreceptors: chemical receptors located close to baroreceptors.

Answer 6

d. Doing so helps flush the CO2 out of the bloodstream and bring more O2 into the bloodstream.

Question 7

3. Cerebrum and hypothalamus: higher brain centers can also alter BP

Answer 7

a. Cerebrum: mood, thoughts, emotions. These are your conscious controls which make your BP go up.

b. Hypothalamus: mediate stress testing through the fight or flight (ANS) mechanism when the body is active or in motion. These are your unconscious controls and involuntary in nature.

Question 8

ii. Hormonal controls: hormonal cues can also alter BP in order to adjust to moment to moment fluctuations

Answer 8

1. Hormones that elevated BP:

a. Epinephrine and norepinephrine: your adrenaline rush. Vasoconstrictors raise R and raise HR contractility

b. Angiotensin II: Powerful Vasoconstrictor which raises R which raises BP. triggers the release of ADH and aldosterone.

c. anti-diuretic hormone (ADH): vasorestrictor = increased R = increased BP. Affects kidneys and causes water retention

d. In summary: HIGH HR, SV, CO, R (VASOCONSTRICTION), V (VOLUME) = HIGH BP

Question 9

ii. Hormonal controls: hormonal cues can also alter BP in order to adjust to moment to moment fluctuations

2. Hormone that decreases BP:

Answer 9

a. Atrial natriuretic peptide (ANP): Makes R go down, which makes BP go down.
* antagonist to aldosterone

Antagonist= to block; prevents your BP from going up.

Question 10

b. Maintaining blood pressure: long-term renal regulation (kidneys do the work)

Answer 10

i. Direct renal regulation

1. When BP is low, the kidneys will: decrease filtration rate
2. When less urine is excreted, fluid is retained in the body
3. Fluid retention = increased volume = increased pressure

Question 11

ii. [SUPER IMPORTANT]

Indirect renal regulation: RAAS

Answer 11

1. RAAS stands for: renin-angiotensin aldosterone system
2. When BP is low, the kidneys release an enzyme called RENIN (biological catalyst)
3. Renin initiates the conversion of the liver hormone called ANGIOTENSINOGEN into ANGIOTENSIN I
4. ANGIOTENSIN I is converted into ANGIOTENSIN II by ACE (angiotensin converting enzyme, from the lungs)

Question 12

5. (Effects of angiotensin II) angiotenson II is a multi-taskimg hormone. It’s activation will lead to:

Answer 12

a. Thirst reflex: increases fluid volume to increase BP

INCREASED VOLUME= INCREASED BP

b. Vasoconstriction: increases R to increase BP

c. Aldosterone releases from adrebal gland: increased slat retention by the kidneys to increase water retention to increase BP (THINK OSMOSIS)