Part 1+2 - Chpt 34: Circulation & Gas Exchange Flashcards
1
Q
Exchange happens at the level of the ___
A
cell - across the membranes
2
Q
Small molecules in and around cells, including O2 and CO2, diffuse
A
down their gradient
3
Q
____ have sufficient membrane surface area in contact with environment to carry out all necessary exchange via difussion.
A
Single celled organisms
4
Q
Animals have what that makes diffusion slow?
A
too many cells
5
Q
Animals with a simple body plan have what two things? list examples of said animals
A
- Gastrovascular cavity - the cells directly in contact with environment
- Functions in both digestion and respiration
- hydras, jellies, flatworms, some invertebrates
6
Q
Animals with a complex body plan have what two characteristics? list examples of animals
A
- a circulatory system
- does not function in digestion
- most invertebrates like molluscs, arthropods, earthworms and all vertebrates
7
Q
What is the difference between animals with a simply body plan and a complex body plan?
A
In a simply body plan - the have a gastro cavity and aids in both respiration and digestion
complex = circulatory system and just respiration
8
Q
What are the 3 elements of a circulatory system?
A
- Fluid - blood or hemolymph
- Vessels
- Pump
9
Q
What do vessels do?
A
carry fluid around the body
10
Q
What does a pump do?
A
powers the circulation of fluid through the vessels
11
Q
What are the two types of circulatory systems?
A
Closed
Open
12
Q
List the characteristics of a Closed circulatory system
A
- fluid is completely contained within vessels - the materials need to diffuse across the vessel membranes for the cells to acquire them
- the circulatory fluid does not mix with interstitial fluid = BLOOD
13
Q
List the characteristics of an Open circulatory system
A
- Fluid escapes vessels through sinuses and bathes cells with materials they need
- Circulatory fluid mixes with interstitial fluid = hemolymph
14
Q
What are sinuses ?
A
spaces that are surrounding organs
15
Q
What are the 3 compartments of fluid in animal’s body?
A
- inside cells
- surrounding cells
- inside circulatory vessels
16
Q
What are inside cells?
A
intracellular fluids
17
Q
What are surrounding cells?
A
extracellular fluid aka interstitial fluid
18
Q
What are inside circulatory vessels?
A
blood or hemolymph
19
Q
If inside cells and inside circulatory vessels are mixed, what kind of system is this?
A
Open circulatory system
20
Q
How do animals circulate oxygen to all cells of the body?
A
within blood vessels
21
Q
List the 3 steps on how O2 is diffuse in a closed circulatory system.
A
- o2 must diffuse across epithelial cells that are lining the blood vessels
- across the interstitium
- across the cell membrane
22
Q
What is epithelial tissue?
A
Sheets of cells covering the outside of the body AND
lining organs + cavities
23
Q
Closed systems allow animals to be ___ and ___ but at a cost
A
bigger
faster
24
Q
List the 2 steps for how O2 must be diffused in an open circulatory system
A
- across the interstitium
- across the cell membrane
25
What is a hemocoel?
a body cavity
26
List the trade offs (+, -) for an Open circulatory system:
1. low hydrostatic pressure
2. metabolically economical - less energy required for the heart to pump
3. less efficient regulation of blood flow to organs - it limits to the upper body portion
27
List the trade offs (+,-) for a closed circulatory system
1. high hydrostatic pressure
2. metabolically expensive - more energy required for heart to pump
3. very efficient regulation of blood flow to organs, animals can be larger and more active
28
What is the most common system and in who?
Open circulatory systems
- all arthropods and some molluscs
29
Who does not have a circulatory system and why?
Sponges - no true tissues
Platyhelminthes
Cnidaria - gastrovascular cavity
Echinodermata (star fish) - water vascular system
Nematoda
30
What system is rare and in who?
Closed
Only vertebrates
- some annelid worms and cephalopods (squid/octopus)
31
Since vertebrate animals are huge and made up of trillion of cells, how do nutrients and oxygen get continuously delivered to every cell of the body and waste removed?
Powerful, high pressure closed circulatory systems
32
Define the cardiovascular system:
the heart and blood vessels in vertebrates
33
Hearts differ across taxonomic groups but
the vessels all share the same plan
34
How does blood flow ?
in one direction AWAY from the heart
35
What are steps in how blood flows away from the heart?
arteries - arterioles - capillaries
-venules - veins - heart
36
Describe the arterial system
moves blood AWAY from the heart and the organs
37
What are arteries?
carry blood from the heart to organs throughout the body
38
What are arterioles?
smalls vessels that bring blood to capillaries
39
From right to left, describe how blood moves in the arterial system
Artery - arteriole - capillaries - venule - vein
40
What do capillaries exchange with?
exchange materials with every cell of the body
41
What are capillaries?
Microscopic, thin, porous vessels that infiltrate tissues as dense networks (capillary beds)
42
Dissolved respiratory gases, nutrients, hormones, electrolytes are exchanged by?
diffusion between the blood and the interstitial fluid around tissue cells.
43
Venous system moves -
blood AWAY from the organs and back to the heart
44
Within organs __ carry blood from the capillaries
venules
45
Venules converge into __ that carry blood back to ___
veins
heart
46
What do arteries and veins convey?
Direction - either away or toward the heart
47
All vertebrate hearts contain two or more
muscular chambers
48
What are the names of the two chambers that all vertebrate hearts contain?
Atria
Ventricles
49
What are atria?
chambers receiving blood entering the heart
50
What are ventricles?
chambers pumping blood out of the heart
51
Single circuit systems contain how many pumps and what animals?
One pump
water-breathing fish (bony & cartilaginous)
52
Double Circuit circulatory system have how many pumps and what animals?
Two pumps
tetrapods - amphibians, reptiles, birds, mammals
53
Single circulation - water breathing fish;
how many circuits and hearts?
1 circuit
2 chambered hearts
54
Describe the process of single circulation in water breathing fish
1. O2 poor (deoxygenated blood) from the body enter the atrium then goes to the ventricle
2. the ventricles contraction pumps the blood to capillary beds in the gills - this is where O2 diffuses into the blood and CO2 diffuses out of the blood
3. Gill capillaries converge into one vessel that carries O2 rich blood to capillary beds throughout the body.
55
How does blood travel around in single circulation? (2)
- around the body and returns to starting point in a single loop
- passes through two sets of capillary beds before returning to the pump: gills and body tissues
56
What type of pressure is in water breathing single circulation?
low pressure - only LP is available to drive blood flow through all the other tissues
57
Describe the process for double circulation in air breathing tetrapods: (2 main steps)
1. Blood moves around the body in two separate loops
2. Each loop has its own separate pump combined into one organ - the heart
58
Describe the how the blood moves around in two separate loops
| The routes
1. Blue route - one moves to the lung capillaries to get rid of CO2 and pick up new O2 - Pulmonary circuit
2. Red route - one to body tissue capillaries to deliver O2 and pick up CO2 waste - Systemic circuit
59
Blue route =
Pulmonary circuit to and from lungs
60
Red route =
Systemic route - to everything else
61
Why does having two pumps benefical?
two pumps in the same organ simplifies coordination of the pumping cycles
62
Right side =
Blue - pulmonary (lungs)
63
Left side =
Red - systemic (body tissue loop)
64
What kind of pressure is in double circulation?
high pressure
65
What natural selection adaptation has shaped ectotherms?
Apneustic
66
What is apneustic?
- intermittent breathers who hold their breath for long periods, fill their lungs periodically with fresh air
- enable circulatory system to temporarily bypass the lungs
67
What natural selection adaptation has shaped endotherms?
Eupneustic
68
What is eupneustic?
continuous breathers
use 10x more energy than equally sized ectotherms
- enable circulatory system to constantly deliver large amounts of oxygen and fuel to tissues
69
Double circulation in amphibians- how many circuits? how many chambered hearts?
2 Circuits
3 chambered heart
70
Describe the process of double circulation in amphibians
1. Two atria supply blood to a single ventricle
2. O2 poor blood fills the right atrium from the body
3. O2 rich blood simultaneously fills the left atrium from the lungs AND SKIN
71
Are the two circuits in amphibians seperate?
No, there is mixing of O2 rich and poor blood in the single ventricle
72
Define spiral value
ridge within ventricle that diverts most O2 rich blood into the systemic circuit and most of the O2 poor blood into the lung circuit
- only known for amphibians
73
What is the advantage for a spiral value?
incomplete separation of ventricle allows submerged frog to shut off blood flow temporary to the ineffective lungs
- blood flow happens through the skin and the skin is the only site for gas exchange (saves some energy)
74
How many circuits and chambers in double circulation for birds and mammals?
2 circuits
4 chambered hearts
75
How does the cardiac cycle work?
Heart contracts and relaxes in a rhythmic cycle
Diastole
Systole
75
Describe the process for double circulation in mammals and birds
1. no mixing of blood! - septum
2. large powerful 4 chambered heart with 2 atria and 2 ventricles
76
What is Diastole?
relaxation phase - chamber fills with blood
77
What is systole?
contraction phase - chambers pump out blood
78
Atrial and Ventricular systoles are
out of phase
79
Why are atrial and ventricular systoles out of phase?
1. prevents ventricles from contracting before the atria has finished
2. allows directionally blood flow - always forward and never backward
3. one way values for chambers and blood vessels that prevent back flow as chambers contact
80
The heart is __
auto-rhythmic meaning its self excitable and set its own pace
- doesn' t need the nervous system to tell itself to beat
81
Respiratory systems transport -
O2 into the body
CO2 out of the body
82
Circulatory system tranports
O2 and nutrients internal - as close as possible to every cell
- collects and transports waste from every cell to organ systems for removal
