Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Animal Physiology > Circulatory System > Flashcards

Circulatory System Flashcards

1
Q

What type of organisms require circulatory systems?

A

large, complex organisms in which diffusion would be far too slow and inefficient = require bulk flow of nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of organisms do not require circulatory systems? what do they use instead?

A

small, unicellular organisms

or simple organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What 5 phyla of animals do not require circulatory systems?

A

Porifera (sponges)
Cnidaria
Echinodermata
Platyhelminthes (flatworms)
Nematoda

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the major functions of a CS?

A

to transport O2 to cells

to remove CO2 and other waste

to transport nutrients

to regulate salts and water

to regulate temperature

to transport signaling molecules (ex. hormones)

for immune responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 3 major components of a CS?

A

a pump or propulsive structure

a system of tubes, channels or spaces

a circulatory fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the function of a pump or propeller?

A

it generates a pressure gradient to move circulatory fluid around the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What direction does circulatory flow around the body? why?

A

unidirectionally because of one way valves in the pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 3 types of pumps?

A

chambered hearts
skeletal muscles
pulsating blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe chambered hearts as pumps

A

hearts have contractile chambers which generate pressure to move fluid into and out of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do skeletal muscles act as pumps?

A

muscle contraction can squeeze vessels to create pressure and move fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how can pulsating blood vessels act as pumps?

A

peristaltic (rhythmic) contractions of vessel walls move fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 2 types fo circulatory fluid?

A

blood (closed)
hemolymph (open)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are 3 types of tubes/channels that are used in the CS?

A

arteries to carry fluid away from heart which branch into arterioles which branch into capillaries

capillaries connect to venules which connect to veins which bring fluid back to the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are capillaries for?

A

they are very fine, delicate and narrow channels where materials are exchanged between CS fluid and tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does CS fluid flow around the body?

A

through the vascular system along/down the pressure gradient generated by the pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is peristalsis?

A

rhythmic wave-like contractions of vessel walls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe a closed CS (fluid, pumps, vessels, mixing with interstitial fluid, contact with tissues, organism types)

A

fluid: blood
pump: heart
vessels: blood vessels
no mixing with interstitial fluid
no direct contact with tissues
vertebrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are materials exchanged between CS fluid and tissues in closed systems?

A

through diffusion or transporters in vessels (ex. capillaries)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe an open CS (fluid, pumps, vessels, mixing with interstitial fluid, contact with tissues, organism types)

A

fluid: hemolymph
pump: can be heart
vessels:
sinuses
mixing with interstitial fluid and direct contact with tissues for exchange
invertebrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are sinuses? what type of CS are they used in?

A

they are spaces in the body cavity where CS fluid enters and mixes with interstitial fluid

in open systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is interstitial fluid? what type of CS is this in?

A

the extracellular fluid that surrounds tissues

in both open and closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 3 major components of blood and their proportion in human blood?

A

plasma (55%)

erythrocytes (45%)

white blood cells and blood clotting cells (< 1%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe blood plasma

A

it’s the liquid component of blood

it’s mostly water, but contains some dissolved ions, organic solutes (HCO3) and proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is serum?

A

blood plasma without the clotting factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the proteins in blood plasma?

A

clotting factors (ex. thrombin, fibrinogen)

carrier proteins (ex. albumin, globulin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is HCO3 for in blood plasma?

A

it’s the form of CO2 that is carried through the blood = buffers blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Describe erythrocytes

A

red blood cells

function in storing and transporting O2 in blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the most abundant cell types in vertebrate blood?

A

red blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the hematocrit?

A

the proportion of blood composed of red blood cells

in humans it’s ~45%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What makes red blood cells/erythrocytes so efficient at storing and transporting O2?

A

RBC have high concentrations of hemoglobin (respiratory pigments) which can each bind 4 O2 molecules

a single red blood cells has extremely high capacity to bind O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What respiratory pigment is involved in binding O2 in red blood cells? how many O2 molecules can one bind?

A

hemoglobin can bind 4 O2 molecules at a time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are examples of white blood cells and clotting cells in blood?

A

leukocytes and thrombocytes (platelets)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the open circulatory fluid?

A

hemolymph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is lymph?

A

fluid in the vertebral lymphatic system involved in immune responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

which phyla have open circulatory systems?

A

urochordata
cephalochordata
annelids (tube worms only)
arthropods
molluscs (only bivalves and gastropods)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Which phyla have closed circulatory systems?

A

vertebrates
molluscs (cephalopods)
annelids (earth worms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How do Porifera obtain nutrients?

A

ciliated cells lining their body cavity move water for diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How do Cnidarian obtain nutrients?

A

muscle contractions of body wall move water for diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How do flat worms obtain nutrients?

A

pharynx contractions bring water into body cavity for diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What type of circulatory systems do Annelids have?

A

both

Polychaete (tube worms) = open

Oligochaete (earth worms) = closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what are the pumps in annelids?

A

heart(s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What system of tubes, channels, or spaces do Annelids use?

A

tubeworms = hemolymph vessels and sinuses

earthworms = blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What type of circulatory systems do Molluscs have?

A

both

bivalves + gastropods = open

cephalopods = closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what type of pumps are used in molluscs?

A

hearts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what type of vascular system is used in molluscs?

A

vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What type of circulatory systems do Arthropods have?

A

open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

How does the CS of crustaceans differ from insects?

A

they’re both open, but insects do not use their CS to transport O2, they have a separate tracheal system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are ostia?

A

pores in the heart(s) of open CS animals that allow hemolymph to enter body cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is unique to the insect CS?

A

CS is used only for delivering nutrients and immune cells, not for O2

Tracheal system used for O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Describe the basic pathway of blood movement in vertebrates

A

aorta pumps blood out of heart

arteries carry blood away from heart and branch into smaller

arterioles which branch into smaller

capillaries which conduct material exchange between blood and tissues and coalesce into

venules which coalesce into

veins which carry blood toward the

ventricle of the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What are the 4 major layers of the walls of vertebrate blood vessels?

A

outermost:
tunica externa
tunica media
tunica intima
endothelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What does the wall of vertebrate blood vessels surround?

A

a lumen (space) where blood flows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Describe the tunica externa

A

the outermost layer of the blood vessel wall

composed of collagen and some elastic fibers, but mostly very rigid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Describe the tunica media

A

the middle layer of blood vessel wall

composed of smooth muscle cells and elastic connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Describe the tunica intima

A

the internal lining of the blood vessel wall

made of smooth endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How does the thickness of the blood vessel wall layers differ in veins compared to arteries?

A

veins have much thinner layers compared to arteries which have very thick tunica externa and tunica media (and thicker intima)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

How does the lumen differ in size between major veins and arteries?

A

the lumen is much larger in veins than arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What layers of blood vessel walls do venules have? how does this affect the structure?

A

only tunica externa and endothelium lining

venules are very rigid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What layers of blood vessel walls do arterioles have? how does this affect the structure?

A

only tunica media and endothelium lining

more elastic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What layers of blood vessel walls do capillaries have? how does this affect the structure?

A

only has endothelial cells

capillaries are VERY fine and delicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Which blood vessel types have one way valves? which do not?

A

only veins do

arteries and capillaries do not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What are the 3 types of capillaries?

A

Continuous
fenestrated
sinusoidal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Which capillary type is most abundant?

A

continuous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Describe continuous capillaries (tissues they’re found in, type of communication, etc)

A

most abundant type
found in skin and muscle tissues
found in the CNS-blood brain barrier

endothelial cells connected by tight junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Describe fenestrated capillaries (tissues they’re found in, type of communication, etc)

A

endothelial cells have pores (fenestrae)

found in kidneys, endocrine organs, intestine

very efficient in exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Describe sinusoidal capillaries (tissues they’re found in, type of communication, etc)

A

very few tight junctions, much more gaps

found in liver and bone marrow

very porous = key for large protein exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

T or F: all capillary endothelial cells are linked by tight junctions

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

T or F: all capillaries leak very little fluid because of tight junctions

A

false, only continuous capillaries

fenestrated and sinusoidal capillaries have pores for exchanging more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

order capillary types from least to most porous/good at exchanging

A

least: continuous (tight junctions only)

mid: fenestrated (pores)

most: sinusoidal (large gaps and fenestrae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

which vertebrates have single circuit CS?

A

water-breathing fish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

which vertebrates have double circuit CS?

A

air-breathing tetrapods (amphibians, birds, reptiles, mammals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What does it mean for the structure of the heart if there’s only one CS circuit?

A

only 2 chambers = 1 atrium, 1 ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Describe the single circuit in water-breathing fish

A

heart pumps out deoxygenated blood via arteries over the gills which have capillaries to exchange O2 in water to oxygenate blood

oxygenated blood is carried through venules and veins throughout the body to exchange O2 with tissues

deoxygenated blood is carried back through veins to the heart

continue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What are the 2 circuits in double CS systems?

A

pulmonary circuit
systemic circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Why do water-breathing fish only have one circuit?

A

because they have a low metabolic rate = low O2 consumption, they do not require blood to be pumped out of the heart at super fast speed/high pressure

systolic pressure = 3045 mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Why do mammals require double circuits?

A

higher metabolic rate and O2 consumption requires heart to pump out blood faster and at higher pressures to move further distances quicker

need a mechanism to decrease pressure coming out of heart to avoid exploding blood vessels = 2 systems

systolic pressure = 120-180 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

How does the systolic pressure of mammals compare to water breathing fish?

A

mammals = 120-180 mmHg

fish = 30-45 mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What side of the heart is the pulmonary circuit controlled by?

A

the right side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What is the function of the pulmonary circuit?

A

the right side of the heart pumps deoxygenated blood to the capillaries at respiratory tissues to pick up O2 and brings oxygenated blood back to the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What side of the heart is the systemic circuit controlled by?

A

the left side of the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What is the function of the systemic circuit?

A

the left side of the heart pumps oxygenated blood from the pulmonary system into the rest of the body

the veins bring back deoxygenated blood into the right side of the heart to enter the pulmonary system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Does the pulmonary system have high or low systolic pressure?

A

low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Does the systemic system have high or low pressure?

A

high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

How many chambers do amphibian and non-bird reptilian hearts have? how is it divided?

A

only partially

into 2 atria and 1 ventricle

frogs have 3 chambered hearts

non-crocodilian lizards have 5 chambered hearts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

How many chambers do frog hearts have?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

How many chambers do non-crocodilian reptiles have?

A

5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Describe the pattern of blood flow in frog hearts

A

both atria pump blood into the ventricle and the ventricle pumps blood into pulmonary and systemic circuits

ventricle pumps deoxygenated blood into pulmonary circuit for lungs and skin capillaries

oxygenated blood returns to the heart

ventricle pumps oxygenated blood into systemic circuit to tissues in body and deoxygenated blood returns to heart

the return of deoxygenated blood to the heart from the systemic system and the oxygenated blood entering from the pulmonary system is where deox and ox blood mix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

In amphibians and non-crocodilian reptiles, explain how the heart is only partially divided

A

oxygenated and deoxygenated blood are mostly separate but can mix and blood can be diverted between pulmonary and systemic circuits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Describe fluid flow in the decapod crustacean (arthropod) heart

A

open CS - fluid is hemolymph

heart pumps hemolymph out through arteries

hemolymph returns to heart via ostia during diastole (relaxation of heart)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

What regulates the flow of hemolymph in crustacean hearts?

A

the opening and closing of ostia during systole and diastole (contraction and relaxation of the heart)

closed during systole
open during diastole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

Where do signals for the crustacean heart to contract originate from (ie., neuro or myogenic)?

A

neurogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

How is the crustacean heart situated within the body?

A

its suspended by ligaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Describe the cardiac cycle steps in arthropods

A

spontaneous rhythmic depolarization of cardiac ganglia neurons causes

cardiomyocetes (cardiac muscles) to contract which

decreases volume of heart to increase pressure

increase in pressure closes ostia

hemolymph is pushed out of heart via arteries

ligaments suspending heart stretch - expanding walls of the heart

heart volume increases to decrease pressure

ostia open

hemolymph is sucked into the heart

(just follow pressure gradient - increased pressure in heart will push hemolymph out, decreased pressure in heart will pull hemolymph in)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What are the 4 layers of vertebrate heart walls?

A

pericardium
epicardium
myocardium
endocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

What is the pericardium in vertebrate heart walls?

A

the outermost tissue composed of connective tissues that surround the heart

it includes the epicardium because the pericardium has 2 parts the parietal and visceral layers and the epicardium is the visceral pericardium

between the parietal and visceral layers there’s the pericardial fluid for protection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

What is the epicardium in vertebrate heart walls?

A

aka the visceral pericardium - the inner layer of the pericardium

it is continuous with connective tissue on the heart and contains the nerves that mediate heart and coronary arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

What is the myocardium in vertebrate heart walls?

A

more internal than the pericardium

the layer of heart muscle cells (cardiomyocetes) - usually the thickest layer

98
Q

What is the endocardium?

A

the innermost layer

thin layer of connective tissue surrounded by epithelial cells

99
Q

What are 2 types of myocardium?

A

the muscle cell layer in heart walls can either be compact or spongy

100
Q

Which animal types have compact myocardium?

A

mammals
birds
reptiles

101
Q

Which animal types have spongy myocardium?

A

fish
amphibians

102
Q

Describe compact myocardium

A

cardiomyocetes are tightly packed together and arranged in a regular pattern

103
Q

describe spongy myocardium

A

loosely connected cardiomyocetes that have spaces between them and are not regularly organized

104
Q

In fish and amphibians, how are spongy myocardium arranged?

A

as trabeculae (extensions) that project into heart chambers

105
Q

How many chambers do fish hearts have?

A

2 chambers (1 atrium and 1 ventricle) but they also have 2 other compartments in series (sinus venosus and bulbus arteriosus)

106
Q

What are the 4 components of fish hearts? In what order (single circuit)?

A

blood enters from body through sinus venosus compartment

blood travels into single atrium

atrium pumps blood through ventricle

ventricle pumps blood into bulbus arteriosus which expands and recoils to move blood into body

107
Q

Which components of a fish heart are contractile?

A

atrium, ventricle and sinus venosus is weakly contractile

bulbous arterious is not contractile

108
Q

Describe the valves in a fish heart

A

passive (no muscles = no contractions)

they open and close depending on pressure gradient to allow blood to flow through unidirectionally

109
Q

What is the functions of bulbous arteriosus?

A

maintains pressure and volume

110
Q

How many chambers do amphibian hearts have?

A

3: 2 atria + 1 ventricle

111
Q

What feature of spongy myocardium is present in amphibian ventricles? what function does it serve?

A

trabeculae in ventricle to prevent mixing of oxygenated and deoxygenated blood

112
Q

How does the amphibian heart direct blood to the pulmonary circuit or the systemic circuit?

A

the conus arteriosus has a spiral fold that directs deoxygenated blood to the pulmonary circuit for the skin and oxygenated blood to the systemic circuit

113
Q

How many chambers does a non-crocodilian reptile heart have? what are they?

A

5

2 atria
3 interconnected (not completely separated) ventricular compartments
- cavum venosum
- cavum pulmonale
- cavum arteriosum

114
Q

are oxygenated and deoxygenated blood separate in non-crocodilian hearts?

A

not completely, but close

there’s a muscular ridge between atria side and ventricular side that is not a complete septum, so blood can flow over top

115
Q

What are the 3 interconnected ventricular compartments of the non-crocodilian reptile heart?

A

cavum venosum
cavum pulmonale
cavum arteriosum

116
Q

describe the flow of blood in non-crocodilian reptile hearts

A

oxygenated blood enters left atrium from pulmonary vein and pumped into cavum arteriosum

cavum arteriosum leads to cavum venosum

from the cavum venosum, oxygenated blood can be pumped out of the heart through the left or right aorta into the systemic system

deoxygenated blood enters the right atrium and is pumped into the cavum venosum

deoxygenated blood in the cavum venosum flows over the muscular ridge into the cavum pulmonale and out of the pulmonary artery

117
Q

How do reptilian hearts direct flow of blood between pulmonary and systemic circuits?

A

blood can be shunted to skip one of the 2 circuits

118
Q

What is right-to-left shunting? why might this occur?

A

in reptilian hearts, deoxygenated blood skips the pulmonary circuit and enters directly into the systemic circuit

occurs during periods of breath-holding - there’s no purpose in wasting energy sending blood through pulmonary system if there’s no oxygen in the respiratory organs

119
Q

What is left-to-right shunting? why might this occur?

A

in reptilian hearts, oxygenated blood skips the systemic circuit and enters directly into the pulmonary circuit to increase O2 delivery to myocardium of heart

120
Q

How many heart chambers do birds and mammals have? what are they?

A

4

2 atria
2 ventricles

121
Q

In mammals and birds, are deoxygenated and oxygenated blood separate?

A

yes completely separated heart chambers

122
Q

Are atria walls thick or thin in birds and mammals?

A

thin

123
Q

Are ventricle walls thick or thin in birds and mammals?

A

thick, but left is thicker than right

124
Q

What separates the 2 ventricles in the mammal and bird heart?

A

intraventricular septum (a complete septum unlike in non-crocodilian reptiles)

125
Q

What are the 4 major valves in birds and mammal hearts?

A

tricuspid atrioventricular (AV) - right atria to right ventricle
bicuspid/mitral atrioventricular (AV) - left atria to left ventricle

pulmonary semilunar - right ventricle to pulmonary artery
aortic semilunar - left ventricle to aorta

126
Q

T or F: valves in birds and mammal hearts (AV and semilunar) are contractile

A

false, they are not muscles

127
Q

Where is the tricuspid AV valve?

A

between the right atria and right ventricle of bird and mammal hearts

128
Q

Where is the bicuspid/mitral AV valve?

A

between the left atria and left ventricle of bird and mammal hearts

129
Q

Where is the aortic semilunar valve?

A

between the left ventricle and aorta in bird and mammal hearts

130
Q

Where is the pulmonary semilunar valve?

A

between the right ventricle and pulmonary artery in bird and mammal hearts

131
Q

Describe blood flow in bird and mammal hearts

A

deoxygenated blood enters right atrium from systemic vein

right atrium pumps deox blood through tricuspid AV valve into the right ventricle

right ventricle pumps deox blood through pulmonary semilunar valve into pulmonary artery to enter pulmonary system

oxygenated blood returns through pulmonary veins into left atrium

left atrium pumps ox blood through bicuspid AV valve into left ventricle

left ventricle pumps blood through aortic semilunar valve into aorta

aorta carries oxygenated blood into systemic circuit

132
Q

What prevents the mixing of deoxygenated and oxygenated blood in bird and mammal hearts?

A

a fully developed septum between right and left compartments of the heart

133
Q

What are the 2 phases of the cardiac cycle?

A

systole - contraction that causes blood to enter circulation

diastole - relaxation that causes blood to flow into the heart

134
Q

Describe the phases of the mammalian cardiac cycle

A

atria and ventricles alternate between systole and diastole

both atria contract simultaneously

pause

both ventricles contract simultaneously

atria and ventricle simultaneously relax to allow the heart to refill with blood

135
Q

Describe the steps of the mammalian cardiac cycle

A

ventricles are both in diastole = pressure greater in atria = AV valves open so that blood flows passively into the ventricles

atria contract to force the rest of the blood into the ventricles

ventricles contract which causes the AV valves to close (no backflow) = ventricle pressure increases

increased pressure in the ventricles causes semilunar valves to open and blood to flow out of heart through arteries

ventricles relax and pressure builds in the atria, semilunar valves close (no backflow) and atria pressure will surpass ventricular to continue this flow

136
Q

How do atrial systole/diastole overlap or not with ventricular systole/diastole in mammals?

A

ventricular diastole overlaps with atrial systole

followed by atrial diastole overlap with ventricular systole

followed by ventricular diastole overlap with atrial diastole until atrial systole happens again

137
Q

why is the left ventricle thicker than the right in mammals?

A

the left ventricle pushes blood out to the systemic circuit which is the rest of the body so blood needs to travel further and maintain a fast velocity so the left ventricle generates a lot more contraction force - needs to have more muscles working

138
Q

is resistance in the pulmonary circuit of mammals high or low? why?

A

low because there’s a very high density of capillaries (larger cross-sectional area of capillaries)

139
Q

Is there high or low pressure required to pump blood through the pulmonary circuit in mammals? why?

A

low - because the lungs are not that far from the heart, less force is needed because less distance to travel

also because the capillaries on the lungs are extremely delicate and high blood pressure would cause them to burst

140
Q

the right side of the mammalian heart is involved in sending blood out into which circuit?

A

the pulmonary circuit via the pulmonary artery

141
Q

the left side of the mammalian heart is involved in sending blood out into which circuit?

A

the systemic circuit via the aorta

142
Q

how does ventricular pressure vary between the left and right ventricles of mammalian hearts?

A

the right ventricle produces significantly less pressure and causes low pressure blood flow into the pulmonary artery

the left ventricle produces significantly higher pressure and causes much higher pressure blood flow into the aorta

143
Q

how does the blood pressure in the left atrium compare to the right atrium in mammalian hearts?

A

they’re comparable, both quite low

but left is slightly higher than right

144
Q

How does blood pressure in the vessels change as blood moves further from the heart (closer to the veins)? why?

A

blood pressure decreases and also variation (between systole and diastole of heart) decreases

blood pressure and the variation in blood pressure between contractions and relaxations of the heart decrease over distance because the blood is farther from the pump and is less affected by the pump

145
Q

Which part of the circulatory system (ex. atria, ventricles, arteries, venules, etc.) has blood pressure changes most affected by the systole and diastole of the heart?

A

the blood pressure in the left ventricle varies the most due to systole and diastole of the heart (significantly more than the rest)

146
Q

What explains the pressure and pulse decrease in arterioles in mammalian hearts?

A

arterioles have increased cross-sectional surface area = reduced pressure, reduced response to systole and diastole

147
Q

Which component of the circulatory system (ex. ventricle, atria, arterioles, venules, veins, etc) has highest blood velocity? why?

A

arteries

because blood is leaving the heart through the arteries, it is being pushed out directly by the contractile force of the heart

148
Q

Which component of the circulatory system (ex. ventricle, atria, arterioles, venules, veins, etc) has lowest blood velocity? why?

A

capillaries

blood flow needs to be slow in the capillaries in order for gas and nutrient exchange to occur

if blood is flowing too fast, O2 can’t be diffused into or out of the capillaries/tissues

149
Q

Which component of the circulatory system (ex. ventricle, atria, arterioles, venules, veins, etc) has intermediate blood velocity?

A

veins

150
Q

How is the blood pressure in the aorta measured?

A

MAP

Mean Arterial Pressure = the average arterial pressure in aorta over a period of time

151
Q

How is MAP calculated (ie., how does it include diastolic and systolic pressure)?

A

MAP = 2/3 diastolic pressure + 1/3 systolic pressure

152
Q

How is blood velocity (distance/unit time) measured?

A

blood velocity = Q/A

where
Q = blood flow - the fluid volume transported per unit of time
A = cross-sectional area of the vessel

153
Q

How is the velocity of flow related to the cross-sectional area of the vessel? give an example of this

A

velocity is inversely related to the cross-sectional area of the vessel

Velocity = Q/A

capillaries: high cross-sectional area but low velocity = allows for more diffusion of O2

154
Q

How does cross-sectional area affect the blood velocity?

A

if cross-sectional area of vessel is small, the velocity will be high (faster)

if A is large, the velocity will be slower

155
Q

What is the law of bulk flow?

A

blood flow = pressure change divided by resistance of blood vessels

Q = delta P / R

where R is proportional to the length of the vessel and length of the vessel is inverse to the radius^4 of the vessel

also where R is proportional to the viscosity of the fluid

156
Q

How is the resistance of a blood vessel influenced by the viscosity of the blood, the length of the vessel, and the radius of the vessel? how does this all effect blood flow?

A

increased viscosity = increased R

increased length of vessel = increased R

R and length of vessel are inverse of radius^4 of the vessel = a slight change to the radius of the vessel has a huge impact on R and blood flow (ex., if radius slightly decreased = huge increase of R = huge decrease of blood flow)

increased R = decreased blood flow (Q)

157
Q

What does Poiseuille’s equation represent?

A

it’s the equation that determines how a change in pressure, the radius and length of a vessel, and the viscosity of blood affects the flow of blood through a particular vessel

it states that pressure is the primary force that regulates blood flow

158
Q

What is the primary force moving blood throughout the body?

A

pressure

159
Q

What do vasoconstriction and vasodilation mean? how do these processes affect blood flow?

A

they refer to the small changes in the radius of blood vessels

because R is inverse to the radius ^4 and blood flow depends on R, minor changes to the radius of blood vessels cause massive changes to resistance and blood flow

160
Q

What does Fick’s Law of diffusion represent?

A

the diffusion rate across capillaries depends on the concentration gradient, surface area, diffusion coefficient, and the distance of diffusion

161
Q

Where do substances diffused across capillaries come from?

A

red blood cells in the blood vessels (remember that it’s red blood cells that have hemoglobin which can bind O2)

162
Q

How thick are capillary walls?

A

very very very thin
< 1 um

163
Q

What makes blood velocity so slow in capillaries?

A

capillaries have diameters of 7 um, but red blood cells have diameters of 8 um so RBCs have to move through capillaries in single file

164
Q

Why do capillaries have such high rates of diffusion?

A

maximized concentration gradient of O2 in RBC

minimized distance of diffusion (cap wall is <1 um thick)

maximized surface area of diffusion = contact between RBC and cap is huge because the diameter of RBC is bigger than capillaries

also, movement of RBCs along capillaries is very slow

165
Q

Where do signals for vertebrate heart contractions originate from (neuro or myogenic)?

A

myogenic

cardiomyocetes undergo spontaneous rhythmic depolarizations without nerve signals

166
Q

What produces coordinated contractions between cardiomyocetes so that the heart functions/contracts as a whole unit?

A

gap junctions between cardiomyocetes electrically couples the cells to pass APs directly from cell to cell

167
Q

What are pacemaker cells?

A

cells derived from cardiomyocytes that produce electrical excitatory signal for muscle contraction

168
Q

Where are pacemaker cells located in fish? in other vertebrates?

A

fish: in sinus venosus
other: in the sinoatrial (SA) node of the right atrium

169
Q

Do pacemaker cells have contractile properties like other muscle cells?

A

no

170
Q

Describe characteristics of pacemaker cells

A

very small
few myofibrils
mitochondria and other organelles present

171
Q

What is the pacemaker potential?

A

the unstable membrane potential of pacemaker cells that allow APs to initiate

172
Q

How does pacemaker potential initiate APs in pacemaker cells?

A

the unstable resting potential in pacemaker cells increases due to opening or closing of ion channels until it reaches threshold to produce an AP

173
Q

What are the steps involved in initiating an AP in pacemaker cells

A

pacemaker potential increases because K channels are open and K+ leaves cell

opening of either If (funny current) or Ih current influx of Na+ generates the AP

T-type and/or L-type Ca2+ channels open and Ca2+ influxes while rapid depolarization

K+ fluxes back into cell as repolarization

174
Q

T or F; there are, like other APs, Na+ sodium gated channels involved in the pacemaker APs

A

false
only K+, If and Ih currents, and T-type and L-type Ca2+ channels

175
Q

What is the If or Ih current?

A

the ‘funny’ current

nonselective cation channels in pacemaker cells which allow the influx of Na+ ions into the cell and cause gradual depolarization of MP

176
Q

How does AP initiation differ in vertebrates where pacemaker cells are in the SA node (not fish)?

A

it’s the same but the HCN channel (cyclic nucleotide gated) encodes the If or Ih currentT

177
Q

T or F: APs in pacemaker cells do not rely on voltage-gated channels like other cells

A

true, they have no voltage gated cells

178
Q

What branch of the nervous system regulates heart rate?

A

Sympathetic (increase) and parasympathetic (decrease) branches of the autonomic NS

179
Q

Which neurotransmitter is involved in increasing heart rate?

A

sympathetic neurons either release norepinephrine to receptors on the pacemaker cells

or send a signal to the adrenal medulla to release epinephrine for the receptors on the pacemaker cells

180
Q

What class of receptors are on pacemaker cells to receive neurotransmitters from nerves?

A

Gs-coupled Beta receptors

181
Q

Describe the signal transduction steps involved in increasing heart rate

A

norepinephrine is released from sympathetic neurons or epinephrine is released from the adrenal medulla and binds to the Beta receptor on pacemaker membranes

binding to receptor causes conformational change which causes Gs to activate cAMP

cAMP activates PKA

PKA activates the funny channel and T-type Ca2+ channels to allow influx of Na+ and Ca2+ into cell causing depolarization of membrane and increased heart rate

182
Q

What part of the nervous system is involved in controlling decreased heart rate?

A

parasympathetic autonomic NS

183
Q

Which neurotransmitter is involved in decreasing the heart rate?

A

acetylcholine

184
Q

describe the steps involved in decreasing heart rate

A

parasympathetic neurons (vagal nerve) releases acetylcholine at the synapse to the pacemaker cells of the heart

muscarinic ACh receptors on pacemaker cells bind ACh which causes conformational change in its Gi subunits

Gi activates GIRK (Kir3) K+ channels = outflux of K+ from cell causing hyperpolarization

Gi inhibits:
- T-type and L-type Ca2+ channels and prevents influx of Ca2+
- If channels = no influx of Na+
this adds to hyperpolarization

more hyperpolarization means it takes longer for depolarization and frequency of AP decreases = decreased heart rate

185
Q

Which parasympathetic nerve is directly involved in decreasing heart rate?

A

vagus nerve

186
Q

What receptor is on the pacemaker cells that is involved in slowing heart rate?

A

Gi coupled - muscarinic ACh receptors

187
Q

Which G subunit is involved in slowing heart rate?

A

Gi

188
Q

What does Gi do when activated? how does this contribute to reducing heart rate?

A

Gi activates GIRK K+ channel = outflux of K+ = hyperpolarization

Gi inhibits T-type and L-type Ca2+ channels = no influx of Ca2+ = hyperpolarization

Gi inhibits funny channel (If) = no influx of Na+ = hyperpolarization

all of this increases the time it takes to depolarize to the AP threshold = slower heart rate

less Cav and Kv channel activity

189
Q

What type of receptor is GIRK? what is it involved in?

A

it’s a G-protein coupled receptor on pacemaker cell membranes involved in reducing heart rate when activated by Gi to allow outflux of K+ out of cell

190
Q

What can explain the plateau peak phase of the APs in cardiomyocetes?

A

depolarization is extended because the refractory period is longer = length of contraction

this is because Ca2+ influxes through L-type channels and K+ channels are slow

191
Q

What is the purpose of extended APs in cardiomyocetes?

A

to prevent tetanus and temporal summation

need one AP at a time

192
Q

describe how APs are propagated along muscle sarcolemma

A

AP causes Na+ channels to open - Na+ influxes = depolarization

depolarization causes L-type voltage gated Ca2+ channels to open - Ca2+ influxes = more depolarization

Na+ channels inactivate = repolarization

K+ channels open = K+ outfluxes = repolarization

Na+/K+ ATPase and Ca2+ ATPases reestablish ion gradients

193
Q

What can cause the heart to contract more forcefully and with more blood?

A

Sympathetic nervous system releasing norepinephrine (or epinephrine) and endocrine system

194
Q

How does cAMP (and PKA) (activated by the binding of norepinephrine to beta adrenergic Gs-coupled receptor on cardiomyocetes) function to increase force of contraction and flow of blood from heart?

A

cAMP activates PKA

PKA phosphorylates L-type Ca2+ channels = influx of Ca2+ into cell = contraction via actino-myosin activity

PKA also phosphorylates Ca2+ channels (RyR) on SR to increase sarcoplasmic [Ca2+] = increase actino-myosin activity = contraction

PKA phosphorylates myosin = increased contraction

PKA also phosphorylates SR Ca2+ ATPase (SERCA) = reduces time for Ca2+ to be removed from cytoplasm during relaxation, decreasing relaxation time = increasing heart rate

195
Q

What are the two types of voltage-gated Ca2+ channels?

A

L-type - long-lasting (need strong depolarization)
T-type - transient

196
Q

What are modified cardiomyocytes? what do they look like, what do they do?

A

elongated cells that appear pale in colour

not contractile but spread AP rapidly through myocardium

can experience rhythmic depolarizations

these cells conduct electrical currents throughout the heart

197
Q

How is electrical current conducted in the mammalian heart?

A

pacemaker cells in the sinoatrial (SA) node initiate an AP

depolarization is carried through the internodal pathway to the AV node

the AV node slowly transmits the signal through the atria via gap junctions = atria contracts

His and Purkinje fibers carry the depolarization from the AV node toward the ventricles

depolarization moves up the ventricles = ventricles contract pushing blood toward the arteries

198
Q

What functions do His and Purjinke fibers have in mammalian hearts?

A

they conduct depolarization

bundles of His fibers carry depolarization from the AV nodes into the ventricles

Purjinke fibers carry depolarization up the ventricles

199
Q

How is the depolarization signal spread throughout the myocardium of mammal hearts?

A

through gap junctions

200
Q

What is ECG or EKG?

A

electrocardiogram

used to assess and diagnose conduction problems in the heart (arrhythmias)

201
Q

What does an ECG/EKG measure?

A

composite APs in cardiac muscle

P wave
QRS complex
T wave

202
Q

What does the P wave show in an ECG?

A

depolarization of the atria caused by the wave of depolarization from the SA node

203
Q

What does the QRS complex show in an ECG? what does the segment between S and the following T wave correspond to?

A

ventricular depolarization

S-T = plateau phase of ventricular AP

204
Q

What does the T wave show in an ECG?

A

ventricular repolarization

205
Q

What is the series of signals shown in an ECG of a normal cardiac muscle?

A

small, short P wave followed by

Q
rapid increase for R
rapid decrease to S

followed by plateau then increase to T

decrease from T to a plateau until next atrial depolarization

206
Q

What is ventricular fibrillation?

A

an arrhythmia that initiates in the ventricles

207
Q

What does an ECG scan look like in a heart with ventricular fibrillation?

A

the peaks and waves are all over the place and there is no rest/relaxation between signals

208
Q

What does cardiac output mean?

A

the volume of blood pumped per unit of time

209
Q

How is cardiac output calculated?

A

CO = HR * SV

where HR = rate of contraction (bpm)
SV = stroke volume (volume of blood pumped per beat)

210
Q

How is stroke volume calculated?

A

volume of blood at the end of diastole minus the volume of blood at the end of systole

211
Q

How does the resting heart rate of a human compare to that of a blue whale? to a mouse? to a reptile?

A

blue whale = 6 bpm
human = 70 bpm
mouse = 580 bpm
lizard = 50 bpm

212
Q

How can cardiac output be modified?

A

by regulating heart rate and/or stroke volume

213
Q

What regulates heart rate?

A

autonomic nerves of the sympathetic (increase) and parasympathetic (decrease) systems and the adrenal medulla (increase)

214
Q

What is bradycardia?

A

decreased heart rate

215
Q

What is tachycardia?

A

increased heart rate

216
Q

What regulates stroke volume of heart?

A

nervous system
hormones
physical factors

217
Q

What is the Frank-Starling effect?

A

If end-diastolic volume is increased = contraction force is increased and stroke volume is increased

the effect: the heart automatically compensates for increased volume of blood returning to heart by shifting the cardiac muscle length-tension relationship

218
Q

what type of curve does the Frank-starling effect produce?

A

an increasing curve between stroke volume and end-diastolic volume (position of muscle length-tension relationship)

219
Q

How does increased sympathetic activity affect the frank-starling effect?

A

the FS curve (position of muscle length-tension relationship) is raised

= higher end-diastolic volume = higher stroke volume

220
Q

How does decreased sympathetic activity affect the frank-starling effect?

A

the curve (position of muscle length-tension relationship) is lowered

= lower end-diastolic volume = lower stroke volume

221
Q

What is it called when the heart automatically compensates for the increased volume of blood returning to the heart when there’s increased end-diastolic volume? (related to FS effect)

A

autoregulation

222
Q

How can cardiac output be used to calculate Mean Arterial Pressure?

A

MAP = CO * TPR

TPR = total peripheral resistance

223
Q

How is MAP maintained within a set range?

A

the body regulates cardiac output and total peripheral resistance to keep MAP within a specific range

224
Q

How is blood flow regulated (what controls blood distribution)?

A

arterioles

they are arranged in parallel so they can change the blood flow to different organs by vasoconstricting or vasodilating (altering resistance of flow)

225
Q

What processes do arterioles use to regulate blood flow? what factor of blood flow do these influence?

A

arterioles can use vasoconstriction or vasodilation to change their resistance to blood flow to either increase or decrease flow to certain organs

226
Q

What 3 ways are vasoconstriction and vasodilation in arterioles controlled?

A

autoregulation - directly controlled by the smooth muscle of arterioles

intrinsic factors (ex. the metabolic state of the tissue)

extrinsic factors (ex. nervous and endocrine systems)

227
Q

What is myogenic autoregulation? what kind of a feedback loop is it? what is the main function?

A

When blood pressure increases in arterioles, their smooth muscle cells are stretched which triggers them to contract

negative feedback loop

functions to prevent excess blood flow into tissues

228
Q

How does metabolic activity of tissues regulate blood flow? what kind of feedback loop?

A

muscle cells in arterioles detect extracellular fluid conditions

vasoconstrict/dilate depending on concentration of metabolites = blood flow matches metabolic needs

negative feedback loop

229
Q

Describe what happens to blood flow during exercise relating to metabolic activities of tissues

A

When tissue metabolic rate is increased (ex. from exercise)

tissues decrease in O2, increase in CO2 (more respiration)

these conditions trigger arteriole smooth muscles to vasodilate > decreased resistance = increased blood flow

increased blood flow allows for increased delivery of O2, removal of CO2 and waste

230
Q

What is another example of how arteriole smooth muscle cells are sensitive to extracellular fluid?

A

if paracrine release of nitric oxide = vasodilation of arterioles = increased blood flow?

231
Q

How does the nervous system influence arteriole regulation of blood flow?

A

release of norepinephrine from sympathetic neurons causes arterioles in:
- cardiac and skeletal muscles to vasodilate = increased blood flow
- other muscles to vasoconstrict

232
Q

does the PNS play a role in vasodilation of arterioles?

A

no, vasodilation occurs in arterioles either as a result of NE release or when sympathetic tone is reduced

233
Q

What other hormones can effect the blood flow regulated by arteriole smooth muscles?

A

vasopressin (ADH) = generalized vasoconstriction

angiotensin II = generalized vasoconstriction

Atrial natriuretic peptide (ANP) = generalized vasodilation

234
Q

what factors influence total peripheral resistance in vasculature?

A

hormones like vasopressin, angiotensin II, ANP
Sympathetic NS + epinephrine or norepinephrine
metabolites and paracrines

^^ effect arteriole diameter ^^

number of red blood cells effects blood viscosity

235
Q

What factors influence cardiac output?

A

Parasympathetic NS reduces heart rate
sympathetic NS (+ ENE and NE) increase heart rate and stroke volume

kidneys (salt/water balance and balance of interstitial fluids/blood) affect blood volume
respiratory pump
skeletal muscle pump
all increase the venous return

the venous return increases the EDV (Frank-Starling effect)

the EDV increases the stroke volume

236
Q

what are baroreceptors? where are they?

A

stretch-sensitive mechanoreceptors in major blood vessel walls (especially carotid arteries and aorta)

237
Q

what do baroreceptors do?

A

detect stretching of blood vessel walls and send signal to medulla oblongata (cardiovascular control center) to regulate MAP

238
Q

What is the cardiovascular control center?

A

the medulla oblongata

239
Q

What type of feedback loop is the baroreceptor reflex?

A

negative

increased MAP causes reduced MAP which causes increase in MAP

240
Q

Where does the baroreceptor reflex occur?

A

in carotid arteries and aorta

Animal Physiology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions