CH EXAM REVIEW ADV. EX. PHYS. ch 4

why does the body need hormonal regulation

if blood pressure drops too low, your organs won't receive enough oxygen.

if blood pressure gets too high, it can damage blood vessels

the body uses several hormone systems to keep blood pressure within a normal range

The three major hormone systems are

renin-angiotensin- aldosterone system (RAAS)

antidiuretic hormone (ADH)

atrial Natriuretic peptide (ANP)

What is the purpose of the RAAS system

increase blood pressure & increase blood volume

When is the RAAS system activated?

blood pressure decreases, blood volume decreases, sodium levels decrease

Explain the RAAS system

for instance, if you get dehydrated. You lose water → blood volume decreases → blood pressure drops → your kidneys notice this drop first → then they begin a chain reaction that raises blood pressure.

RAAS system step by step

kidneys release renin → liver produces angiotensinogen, renin converts it into angiotensin I → lungs ACE enzyme converts angiotensin I into angiotensin II → angiotensin II is the major hormone that has several effects.

Angiotensin II does 4 important things

vasoconstriction, stimulates aldosterone, stimulates ADH release, stimulates thirst

what does vasoconstriction look like in Angiotensin II

blood vessels constrict → resistance increases → blood pressure increases

what does stimulation of aldosterone look like in Angiotensin II and where

Location in the adrenal cortex, aldosterone tells the kidneys: “keep sodium”. water follows sodium → blood volume increases → blood pressure increases

what does stimulation of ADH release look like in Angiotensin II and where

Location is in the posterior pituitary. ADH causes the kidneys to retain water → blood volume increases → blood pressure increases

what does stimulation of thirst look like in Angiotensin II and where

location is in the hypothalamus. you drink more water → blood volume increases → blood pressure increases.

RAAS flow chart (write out when u see it)

Low blood pressure → kidney → renin → liver (angiotensinogen)→ angiotensin I → ACE (lungs) → angiotensin II → Vasoconstriction, aldosterone, ADK, Thrist → higher blood pressure

location of where the structures are located

renin - kidney

angiotensinogen - liver

ACE - lungs

aldosterone - Adrenal cortex

ADH - posterior pituitary

thirst center - hypothalamus

where is each component of the RAAS system located

renin - released from the kidneys (juxtaglomerular cells)

angiotensinogen - produced by the liver

ACE - primarily locates on the endothelium of the lungs

Angiotensin II - formed in the bloodtream after ACE acts on angiotensin I

aldosterone → released from the adrenal cortex

ADH- released from the posterior pituitary

thirst center- located in the hypothalamus

aldosterone purpose

retain sodium. water follows sodium so as a result higher blood volume, higher blood pressure.

ADH also called vasopressin purpose

converts water. The kidneys reabsorb more water, less water leaves in urine so blood volume increases, blood pressure increases

ADH is relaesed when

blood pressure decreases, blood volume decreases, plasma osmolality increases

Atrial Natriuretic peptide (ANP)

this hormone does the opposite of RAAS. it is released when the atria becomes overstretched because blood volume is too high.

Atrial Natriuretic peptide (ANP) goal and effect

lower blood pressure. it excretes sodium, excretes water, reduces blood volume, vasodilation, inhibit aloddsterone, inhibit renin, which will lower blood pressure

sympatheic NS

helps regulate blood pressure quickly

sympatheic NS main neurotranmitter and main hormone

norepinephrine . epinephrine

sympathetic receptors B1 location and effects

located in heart. increases heart reate, contractility, cardiac output

sympathetic receptors A1 location and effect

located in most blood vessels. it vasoconstricts leading to higher TPR, which leads to higher blood pressure

sympathetic receptors B2 location and effect

located in skeletal muscles, coronary arteries and bronchioles. Its affect is vasodilation and bronchodilation

parasympathetic nervous system main neuro transmitter and main receptor

acetylcholine. M2

parasympathetic nervous system effects

heart rate and cardiac output

baroceptors

these are pressure sensors located in carotid sinus and aortic arch

baroreceptors purpose

monitor blood pressure increases

what happens with baroreceptors

if blood pressure increases → baroreceptors fire more → brain decreases sympathetic activity → HR decreases→ BP decreases

if blood pressure decreases→ baroreceptors fire less → sympathetic activity increases → HR increases → blood pressure increases

chemoreceptors are located in

carotid bodies and aortic bodies

chemoreceptors are monitor

oxygen, carbon dioxide and pH.

if oxygen becomes low, they stimulate sympathetic activity to help restore oxygen delivery

short term blood pressure regulation

sympathetic nervous system, parasympathetic nervous system, baroreceptors (works in seconds)

Long term blood pressure regulation

RAAS, ADH, Kidneys (works over hours to days)

why does aldosterone increase blood pressure?

aldosterone tells the kidneys to keep sodium and water follow sodium so more water stays in the bloodstream. This makes blood volume increase and more blood volume meand higher blood pressure

Why does ADH increase blood pressure

ADH tells the kidneys to reabsorb water. This increases blood volume. More blood volume increases venous return, preload, stroke volume cardiac output, and ultimately BP

Why does ANP lower blood pressure

ANP is released when blood volume is too high. It causes the kidneys to remove sodium and water from the body. This decreases blood volume and blood pressure.

(it also opposes the RAAS system)

What does RAAS stand for

Renin-angiotensin-aldosterone system

When is RAAS activates?

low blood pressure, low blood volume, or low sodium

where is renin released

kidneys (juxtaglomerular cells)

where is angiotensinogen produced

liver

where is ACE primarily located

lung endothelium

what converts angiotensin I into angiotensin II

ACE

4 major effects of angiotensin II

vasoconstriction, aldosterone release, ADH release, thirst stimulation

where is aldosterone released

adrenal cotex

what does aldosterone do?

increases sodium reabsorption, water follows, increasing blood volume and BP

where is ADH released

posterior pituitary

What does ADH do

Increases water reabsorption by the kidneys

what is another name for ADH

vasopressin

where is ANP released from

the atria of the heart

what does ANP do

lowers blood pressure by promoting sodium and water excretion and inhibiting RAAS

where are baroreceptors located

carotid sinus and aortic arch

what do baroreceptors detect?

blood pressure (stretch)

where are chemoreceptors located

carotid and aortic bodies

what do chemoreceptors monitor?

oxygen, carbon dioxide, and pH

which receptor increases heart rate and contractility

B1

which receptor causes vasoconstriction

A1