circulation

Question 1

2 main functions of circulatory system

Answer 1

transport and exchange respiratory gases
transports nutrients, hormones, immune cells

Question 2

do all animals have circulatory systems? If not, what do they have and how does it work?

Answer 2

no not all do, some have gastrovascular cavities where gases and nutrients diffuse

Question 3

What are the three main features of circulatory systems?

Answer 3

fluid, vessels, pump

Question 4

What is an open circulatory system? What is a closed circulatory system? What flows
through each system, how do they differ? What are their primary functions? Which
types of animals have which system?

Answer 4

open:
invertebrates
fluid: hemolymph mixed with interstitial fluid
function: transport nutrients and waste. no gas exchange

closed:
vertebrates and inverts
fluid: blood in closed vessels which has red blood cells
function: gas exchange

Question 5

List the vessels in the order in which blood flows away from the heart

Answer 5

heart-> artery-> capillaries-> vein-> heart

Question 6

Define the vessels in the order in which blood flows away from the heart

Answer 6

artery: carries blood away from heart
capillaries: microscopic vessels with thin porous walls (site of gas and nutrient exchange)
vein: carries blood back to heart

Question 7

What is the atrium? What is the ventricle?

Answer 7

atrium: recives blood
ventricle: pumps blood out

Question 8

What is single circulation? How does blood flow and what happens to oxygen? Which
animals have this system? What happens to the speed of blood flow and how is this
corrected?

Answer 8

single circulation: blood travels through body in a single loop
- heart pumps once to take blood to respiratory surface/body (gills) and then to body where it slows down
- oxygen rich blood when it reaches gills and oxygen poor blood from body to heart to gills
-fish have this system
- blood flow speeds up when muscles contract (during swimming)

Question 9

Describe both examples of double circulation presented in class. How does blood flow
and what happens to oxygen? How does the heart differ in each example? What circuits
are involved in each example? Which animals use which type of double circulation?

Answer 9

In mammals (example panda)
-pulmonary circuit: right side of the heart pumps oxygen poor blood into beds and oxygen moves in (heart to lungs)
-systematic circuit: left side of the heart pumps oxygen rich blood to the rest of the body
- four chambered heart/ ventricles, divided

In amphibians (example frog)
- pulmocutaneous circuit: right side of heart pumps oxygen poor blood blood into beds and oxygen moves in (heart to lungs/skin)
- systematic circuit: heart to body to heart
- three chambered heart/ventricles not divided
-

Question 10

What is an intermittent breather?

Answer 10

frog example: when underwater, incomplete division of ventricle allows frogs to shut off blood flow to lungs and shift it to skin

Question 11

In what way can the 3 chambered heart observed in amphibians be adaptive?

Answer 11

allows frogs to shift blood flow to skin instead to lung diffusion

Question 12

4 major components of blood

Answer 12

plasma: the liquid portion that contains dissolved nutrients, hormones, gases
red blood cells: transport oxygen
platelets: help form blood clots
white cells: immune defenses against invaders

Question 13

What is a red blood cell? What does it do? What important protein does it contain?

Answer 13

-red blood cells transport oxygen
-make up 99% of the blood’s cellular component
-contains the protein hemoglobin that transports oxygen
- also called an erythrocyte.

Question 14

What is hemoglobin? why are red blood cells red?

Answer 14

-Protein in red blood cells that binds/transports oxygen
- due to iron in hemes

Question 15

What is affinity and how does oxygen binding to hemoglobin change affinity?

Answer 15

-affinity is a natural liking
-cooperativity
* when oxygen binds to one subunit the shape changes to increase affinity for oxygen
* when a subunit unloads the shape changes t decrease affinity for oxygen
- hemoglobin has high affinity for oxygen when PO2 is high and low affinity when PO2 low

Question 16

Where (in lungs or tissue) is partial pressure for oxygen high? Where is it low? How does
that impact the affinity of hemoglobin for oxygen?

Answer 16

lungs: high O2; high affinity of hemoglobin=high O2
tissue: low O2; low affinity of hemoglobin=low O2

Question 17

Explain the oxygen hemoglobin dissociation curve. Start in the top right corner of the
figure from class and explain what is happening to hemoglobin affinity for oxygen (i.e.,
hemoglobin saturation), oxygen partial pressure, and oxygen unloading as you move to
the left.

Answer 17

lungs: high PO2, high affinity in hemoglobin
tissue and rest and during exercise: low PO2, low affinity in hemoglobin
- because of subunit cooperativity a slight drop in O2 causes a large increase in O2 unloading

Question 18

How does exercise shift this curve? If you look at a set unit of oxygen partial pressure
(e.g., 40 on the figure) what does an increase of carbon dioxide do to hemoglobin
saturation? What does that mean with respect to oxygen availability to tissue?

Answer 18

• there is a shift to the right meaning more O2 is relased
  -CO2 increaser
  -PH decreases in blood and hemoglobin retains less O2
  -more oxygen unloaded

Question 19

Where are animals naturally exposed to low oxygen conditions?

Answer 19

deep sea

Question 20

3 respiratory adaptations found in deep sea diving mammals (seal example)?

Answer 20

1. more blood (stores more oxygen)
2. more myoglobin
3. blood not routed to muscles because they use myoglobin

Question 21

What is myoglobin?

Answer 21

oxygen storing protein in muscle

Question 22

Example in humans of adaptation to deep sea diving?

Answer 22

enlarged spleen
- spleen hold oxygenated red blood cells
-50% larger
-infuses red blood cells into the circulation during dives

Question 23

What pathway is activated by hypoxia that leads to red blood cell increases?

Answer 23

hypoxia-epo-kidney-epo-bone marrow-red cells-O2 transport

Question 24

How is this pathway activated by endurance athletes to improve performance?

Answer 24

• injecting epo
• taking epo is a form of doping in atheletes

Question 25

Tibetans who lived in high altitudes (under extreme hypoxia)

Answer 25

Their genes reduced red blood cell numbers causing blood to thicken and increases oxygen efficiency