anatomy - unit 2

what is the role of the arch of the aorta

after the blood leaves the heart, one of the vessels have the highest pressure

what are the major blood vessels

common carotid and arch of aorta

what are baroreceptors ?

sensitive pressure receptors

what do baroreceptors do?

stretch of the vessel, movement of the blood, blood comes through, it stretches the walls of the vessels.

what happens when the baroreceptors **stretch the the walls of the vessels TOO much?**

pick up info and sends, “being stretched too much”

what happens when the baroreceptors **stretch the the walls of the vessels TOO LITTLE?**

pressure will be low

why is high blood pressure important?

can deliver blood to where it needs to go

why is high blood pressure bad?

it can damage structures

what information does the baroreceptor need to know?

important for the receptor to know if its stretched too much or not stretched enough

what do chemoreceptors detect?

detect o2, co2, h+ ions,

what is chemoreceptor sensitive to?

co2

what do chemoreceptors do?

responding to changes in chemical concentrations of the blood

what is the final outcome of chemoreceptors?

can now change breathing/heart contractility to respond to concentration of the blood

where is our majority of our blood located?

at any given time, the majority of blood is in the systemic veins

what is atherosclerosis?

built up of plaques - a huge problem

what is the mnemonic for atherosclerosis

move around pot holes to avoid flat tires, slowing it down. In the blood vessel, the blood has to move around the obstructions, moving around obstructions and creating more resistance and more pressure. More pressure can create more obstructions

what happens when the vessel radius is more open in atherosclerosis?

vessel more open and easier for blood to move through

increase vessel radius, decrease peripheral resistance

what happens when the vessel radius is more closed in atherosclerosis?

decrease vessel radius, increase peripheral resistance

what happens when the vessel radius is more narrow in atherosclerosis?

narrower the vessel, makes it harder for the blood to move through = more pressure

what is blood pressure?

force of blood pushing on the walls of the blood vessel

vessels should be keeping the blood w/in

the volume is pushing on the walls of its container

when is blood pressure the highest?

systemic artery (aorta specifically)

when is blood pressure the lowest?

systemic veins

why is blood pressure the highest in systemic artery?

when blood pumped out of the heart w a lot of force, into the aorta (there is a lot of pressure built up from that)

normal heart pressure

120/80

120 = systolic (contracting)

80 = diastolic (relaxing)

what happens at the capillaries?

want exchange, but need to take its time

what is the mnemonic for capillaries?

going shopping and taking time, putting things in the cart of fancy wine/cheese

BUT if you went in the store quickly, dont have time to look at all the fancy wine/cheese - there isnt that exchange b/t Herbert and the shelves

why do we want to slow the exchange w the capillaries down?

want the blood to take its time so it can exchange. wants to take its time to see what the tissue has

how do we let the blood take its time in the capillaries?

goes through all the little capillaries, its going to takes its time

what is the reason we branch in the capillaries?

reason to branch as we move out is to slow blood down to make it make efficient exchange at the capillaries.

what determines blood pressure ?

1. Peripheral resistance
2. cardiac output
3. blood volume

what is peripheral resistance?

trying to move freely , this is trying to keep you from moving freely.

mnemonic for peripheral resistance

wind against you when you are walking, hard to move. PR, apposing force to movement (not much we can change)

what happens to resistance and BP in peripheral resistance

increase resistance, increase BP

Decrease resistance, decrease BP

can you change the length in blood vessels

no, short , less resistance

what is pulmonary circuit in PR? (length of vessels, resistance, pressure)

shorter vessels , less resistance and less pressure

what is systemic circuit in PR? (length of vessels, resistance, pressure)

long vessels, more resistance, and more pressure

how does cardiac output influence blood pressure?

CO increases, BP increases

what is cardiac output?

amount of blood pumped out of teh heart in one minute

what happens when there is **more** pumping in cardiac output?

pumping more blood out of the heart = more force , heart rate increases , more pressure

what happens when there is **less** pumping in cardiac output?

less pumping = less pressure

what does blood volume impact?

blood volume impacts blood pressure

mnemonic for blood volume

water balloon **NOT FILLED** all the way = dont pop

water balloon **FILLED** all the way = pops

what helps maintain blood pressure ?

water pill - aids to not retain water. get rid of blood volume, makes blood pressure go down

what is the important organ for regulating blood pressure ?

kidneys

hormonal regulation (bv/bp)

increase BV, increase BP

decrease BV, decrease BP

what is the term for thick blood?

blood viscosity

what is blood viscosity?

how much water/red blood there is

what happens when there is more red blood cells (blood viscosity)

thicker the blood is = more BP

What does this image show?

talking about pressure

what does the black line show?

changing from time leaving heart to go to other vessels

what is the change overtime?

highest when leaving the heart, stable through the large arteries, then arterioles - there is a decline and continuous declining

why is this important?

decline in pressure, creates a pressure gradient , keeps blood moving forward

what happens if there wasn’t a pressure decline?

dont want HBP in capillaries, if pressure was too high, lead to damage to capillaries (explode)

what determines peripheral resistance (4 things)

* vessel radius
* blood viscosity
* blood vessel length
* obstructions in vessels

what determines cardiac output (2 things)

* stroke volume
* heart rate

what determines blood volume (2 things)

* water loss
* water gain

BP in the veins (high or low)?

low

what is skeletal muscle pump?

lower limb

what prevents backflow?

valves - will close

what do the muscles do in the legs when they contract?

squeeze the blood up push forward towards heart

what happens to the blood when the muscle **contracts**?

muscle squeeze = push valves open, blood moves forward toward the heart

what happens to the blood when the muscle **relaxes**?

blood pushes back on the valves, closes the vales to prevent back flow

what is the respiratory pump?

change pressure in thoracic and abdominal cavity.

move blood back towards heart - moving against gravity, trying to get back to the heart

what happens when you breath in/out

changing pressure and helping push the blood going back towards the heart

how to maintain homeostasis? two systems

endocrine and nervous system

is endocrine system long or short term?

long term

is nervous system long or short term?

short term

what does the nervous system do for bp?

immediate response but short

what does the endocrine system do for bp?

able to sustain response, take time to act

why do we need both endocrine and nervous system?

need both ways of regulating to have short/long term

what do we need to regulate in short/long term?

blood pressure

what does sympathetic neurons do?

increase heart rate / contractility = increases CO

what does parasympathetic neurons do?

decrease heart rate = decreases CO

what happens when blood pressure **increases** above normal range? *short answer*

receptor: baroreceptors in the carotid sinus, detects **increase pressure** and fire action potentials at a fast rate

\
control center: impulses travel to medulla of the brainstem

\
response: medulla inhibit **sympathetic activity** and decreases heart rate, lowering CO

\
homeostatic range: BP decreases and decreases response from medulla. now in normal range

what happens when blood pressure **decreases** above normal range? *short answer*

P increase receptor: baroreceptors in carotid sinus detect **decrease pressure** and **lowers firing rate**

\
control center: impulses travel to medulla of the brainstem

\
response: trying to raise BP, **increase sympathetic and decrease parasympathetic**. allows heart rate to increase

\
homeostatic range: BP increases and responses go back to normal

Mechanisms impacting peripheral resistance (increase peripheral resistance)

endocrine

* epinephrine
* Norepinephrine
* Angiotensin-II
* Renin secretion

Neural

* increased sympathetic activity

Mechanisms impacting peripheral resistance (decrease peripheral resistance)

Endocrine

* decreased renin secretion

Neural

* increased parasympathetic activity
* \

Mechanism affecting cardiac output (increase rate and contraction)

endocrine

* thyroid hormone
* Epinephrine
* Norepinephrine

Neural

* increased sympathetic activity
* Decreased sympathetic activity

Mechanism affecting cardiac output (decrease rate and contraction)

Endocrine

* atrial natriuretic peptide

Neural

* increased parasympathetic activity
* Decreased sympathetic activity

\

mechanism affect blood volume (increased blood volume)

endocrine

* angiotensin-II
* ADH
* Aldosterone

Renal

* increased h2o retention

mechanism affect blood volume (decrease blood volume)

Endocrine

* atrial natriuetic peptide
* Decreased h2o retention

hypertension

HBP, high all the time (common)

Primary = don’t know what is causing it

Secondary = cause is determined, something going on that leads to HBP

Hypotension

systolic = pressure lower than 90

Diastolic = lower than 60

\
Can be beneficial causing less stress to heart/vessels

(Too low, not getting enough blood to vital organs)

\

Normal Blood pressure

120/80

Capillaries

bring more blood to the tissue to have exchange occur (spend more time in the aisle to pick what you want from the store)

* want good exchange to happen
* Delivering blood to tissue, so exchange can occur

why is fenestration beneficial?

* allows for more diffusion/osmosis for better exchange
* Move things in/out of capillaries

how to control blood flow if we dont have those layers of tissue (blood flow through capilalry bed)

regulate blood flow = precapillary sphincters

what happens when precapillary sphincters open

open = blood moves through it and goes through everything

What happens when precapillary sphincters close

control flow = bands of muscle can constrict and block off flow into the capillary bed

* bed moves straight through the channel and to venuel (limits how much exchange there is)

what is myogenic mechanism

using smooth muscles of arterioles

Myogenic mechanism (resistance increase)

increase resistance = decrease blood to tissue

Myogenic mechanism (resistance decrease)

Decrease resistance = increase more blood to tissues

metabolic controls

how much energy a tissue needs

Ex: skeletal muscle using a lot of ATP, sends signals to get more blood and it will get more blood flow

pressure work in capillary (hydrostatic pressure)

ressure of water pushing out of capilalry

Pressure in capaillary (osmotic pressure)

water pushing into the capillay

how much blood is in the body

5-6 liters of blood in the body , makes up 8% of the body

blood functions of preserving acid/base homeostasis

pH of blood = maintained between 7.35 and 7.45

What is blood made up of ?

Huge portion of blood is made of water (plasmid)

Erythrocytes structure benefits

* fits in tiny capillaries
* The shape allows to squish and fit in a small space
* Shape gives greatest surface area to carrying Capillary capacitvity

What is the job of carrying erythrocytes

Carry o2, need red blood cells to do that