42 Chapter Flashcards
(131 cards)
1
Q
The alternative to a circulatory system is a ______________, which ____________
A
Gastrovascular cavity, which functions in the distribution of substances throughout the body, as well as in digestion.
2
Q
A circulatory system has three basic components:
A
A circulatory fluid, a set of interconnecting vessels, and a muscular pump, the heart.
3
Q
Hemolymph
A
The circulatory fluid of an open circulatory system.
4
Q
In an open circulatory system,
A
The hemolymph is also the interstitial fluid that bathes body cells.
5
Q
Blood
A
The circulatory fluid of a closed circulatory system.
6
Q
In a closed circulatory system,
A
A circulatory fluid, called blood is confined to vessels and is distinct from the interstitial fluid.
7
Q
Cardiovascular system
A
The closed circulatory system of humans and other vertebrates
8
Q
Three main types of blood vessels
A
Arteries, veins, and capillaries
9
Q
Arteries
A
Carry blood from the heart to organs throughout the body
10
Q
Arterioles
A
Branches of arteries within organs.
11
Q
Capillaries
A
Microscopic vessels with very thin, porous walls
12
Q
Capillary beds
A
Networks of capillaries; found in tissues
13
Q
Venule
A
A vessel that conveys blood between a capillary bed and a vein
14
Q
Veins
A
The vessels that carry blood back to the heart
15
Q
At their downstream end, capillaries converge into ________, and ________ converge into ________
A
Venules, venules, veins
16
Q
Arteries and veins are distinguished by the direction in which they carry blood, not by the O2 content or other characteristics of the blood they contain.
A
True
17
Q
Portal veins
A
Carry blood between pairs of capillary beds
18
Q
Atria
A
The muscular chamber of the heart that receives blood entering the heart
19
Q
Ventricles
A
The muscular chambers of the heart responsible for pumping blood out of the heart
20
Q
Single circulation
A
A circulatory system consisting of a single pump and single circuit, in which blood passes from the sites of gas exchange to the rest of the body before returning to the heart.
21
Q
Double circulation
A
A circulatory system consisting of separate pulmonary and systemic circuits, in which blood passes through the heart after completing each circuit.
22
Q
Pulmonary circuit
A
A part of the circulation where one pump, the right side of the heart, delivers oxygen-poor blood to the capillary beds of the lungs.
23
Q
Pulmocutaneous circuit
A
A part of the circulation where one pump, the right side of the heart, delivers oxygen-poor blood to the capillary beds of both the lungs and the skin.
24
Q
Systemic circuit
A
The branch of the circulatory system that supplies oxygenated blood to and carries deoxygenated blood away from organs and tissues throughout the body.
25
Blood pressure is much higher in the systemic circuit than in the gas exchange circuit in double circulation
True
26
Aorta
Conveys blood to arteries leading throughout the body
27
Coronary arteries
Supply blood to the heart muscle itself
28
Oxygen-poor blood from the head, neck, and forelimbs is channeled into a large vein, the _____________
Superior vena cava
29
The __________, drains blood from the trunk and hind limbs.
Inferior vena cava
30
The two venae cavae empty their blood into the ____________, from which the oxygen-poor blood flows into the __________
Right atrium, Right ventricle
31
Sternum
Breastbone
32
Left ventricle function
Pumps blood throughout the body via the systemic circuit
33
Although the left ventricle contracts with greater force than the right ventricle, it pumps the same volume of blood as the right ventricle during each contraction.
True
34
When the heart contracts, it ____________.
Pumps blood
35
When the heart relaxes, ______________
Its chambers fill with blood
36
One complete sequence of pumping and filling is referred to as ____________
The cardiac cycle
37
Systole
The contraction phase of the cardiac cycle
38
Diastole
The relaxation phase of the cardiac cycle
39
Cardiac output
The volume of blood each ventricle pumps per minute
40
Heart rate
The rate of contraction (number of beats per minute)
41
Stroke volume
The amount of blood pumped by a ventricle in a single contraction
42
Two factors determine cardiac output:
Heart rate
Stroke volume
43
Atrioventricular (AV) valve
Lies between each atrium and ventricle; functions to keep blood from flowing back into the atria
44
Semilunar valves
A valve located at each exit of the heart, where the aorta leaves the left ventricle and the pulmonary artery leaves the right ventricle. Function to prevent the backflow of blood from the arteries into the ventricles.
45
Right ventricle function
Pumps blood to the lungs via the pulmonary arteries
46
Left atrium function
Receives oxygen-rich blood from the lungs via the pulmonary veins
47
Right atrium function
Receives oxygen-poor blood from the two venae cavae, which then flows into the right ventricle
48
Heart murmur
An abnormal sound produced by a defective valve which allowed blood to squirt backward
49
Autorythmic cardiac muscle cells
Can contract and relax repeatedly without any signal from the nervous system
50
Sinoatrial (SA) node, or pacemaker
A cluster of autorhythmic cells that sets the rate and timing at which all cardiac muscle cells contract.
51
Electrocardiogram (ECG or EKG)
A record of the electrical impulses that travel through heart muscle during the cardiac cycle
52
Atrioventricular node
A region of specialized heart muscle tissue between the left and right atria where electrical impulses are delayed for about 0.1 seconds before spreading to both ventricles and causing them to contract
53
The signals from the AV node are conducted to the heart apex and throughout the ventricular walls by specialized structures called …
Bundle branches and Purkinje fibers
54
Epinephrine
The “fight or flight” hormone secreted by the adrenal glands; speeds up the pacemaker
55
Endothelium
A single layer of flattened epithelial cells
56
The exchange of substances between the blood and interstitial fluid occurs only in capillaries because only there are blood vessels walls thin enough to permit this exchange.
True
57
A vein has a wall only about a third as thick as that of an artery.
True
58
Unlike arteries, veins contain valves, which maintain a unidirectional flow of blood despite the low blood pressure in these vessels.
True
59
Systolic pressure
Arterial blood pressure when the heart contracts during ventricular systole
60
Pulse
The rhythmic bulging of the artery walls with each heartbeat
61
Diastolic pressure
Blood pressure in the arteries when the ventricles are relaxed
62
Narrowing of the arterioles, vasoconstriction, has what effect on blood pressure?
It increases blood pressure upstream in the arteries.
63
When the smooth muscles relax, the arterioles undergo vasodilation. What effect does vasodilation have on blood pressure?
Vasodilation causes blood pressure in the arteries to fall.
64
Precapillary sphincters
Rings of smooth muscle located at the entrance to capillary beds
65
Lymphatic system
Includes a network of tiny vessels intermingled among capillaries of the cardiovascular system, as well as larger vessels into which small vessels empty. It functions to transport the lost fluid and proteins to the blood.
66
Lymph
The fluid lost by the capillaries
67
Disruptions in lymph flow often result in fluid accumulations, or __________, in affected tissues
Edema
68
Lymph nodes
Lymph-filtering organs which play an important role in the body’s defense.
69
Blood electrolytes
Inorganic salts in the form of dissolved ions in plasma
70
Normal human blood pH
7.4
71
Plasma has a much higher protein concentration than interstitial fluid, although the two fluids are otherwise similar
True
72
Platelets
Cell fragments that are involved in the clotting process
73
Erythrocytes
Red blood cells
74
Biconcave
Thinner in the center than at the edges
75
Hemoglobin
The iron-containing protein that transports O2
76
Erythrocytes also lack mitochondria and generate their ATP exclusively by anaerobic metabolism. Oxygen transport would be less efficient if erythrocytes were aerobic and consumed some of the O2 they carry.
True
77
One erythrocyte can transport about _________ O2 molecules
1 billion
78
Leukocytes
White blood cells
79
Phagocytic leukocytes
Engulf and digest microorganisms as well as debris from the body’s own dead cells
80
Lymphocytes
Leukocytes that develop into B cells and T cells that mount immune responses against foreign substances.
81
Blood contains __ major types of white blood cells
5
82
Erythropoietin (EPO)
A hormone synthesized by the kidneys that stimulates the generation of more erythrocytes
83
Coagulation
The conversion of liquid components of blood to a solid clot
84
A break in a blood vessel wall exposes proteins that attract platelets and initiate coagulation
True
85
Coagulant
A sealant
86
Fibrinogen
The inactive form of a coagulant
87
Thrombin
Enzyme that converts fibrinogen to fibrin
88
Thrombus
Clots forming within a blood vessel
89
Atherosclerosis
The hardening of the arteries by accumulation of fatty deposits
90
Low-density lipoprotein (LDL)
Delivers cholesterol to cells for membrane production
91
High-density lipoprotein
Scavenges excess cholesterol for return to the liver
92
Individuals with a high ratio of __________ are at substantially increased risk for atherosclerosis.
LDL to HDL
93
In atherosclerosis, damage to the arterial lining results in ___________, the body’s reaction to injury
Inflammation
94
Heart attack (myocardial infarction)
Is the damage or death of cardiac muscle tissue resulting from blockage of one or more coronary arteries
95
Stroke
The death of nervous tissue in the brain due to a lack of O2
96
Hypertension
High blood pressure
97
Gas exchange
Is the uptake of molecular O2 from the environment and the discharge of CO2 to the environment
98
Partial pressure
Is the pressure exerted by a particular gas in a mixture of gases
99
A gas always undergoes net diffusion from a region of higher partial pressure to a region of lower partial pressure
True
100
Respiratory medium
The source of O2
101
Water’s lower O2 content, greater density, and greater viscosity mean that aquatic animals such as fishes and lobsters must expend considerable energy to carry out gas exchange
True
102
Respiratory surfaces tend to be large and thin
True
103
Gills
Are outfoldings of the body surface that are suspended in the water
104
Ventilation
Movement of the respiratory medium over the respiratory surface
105
Countercurrent exchange
The exchange of a substance or heat between two fluids flowing in opposite directions
106
Tracheal system
A network of air tubes that branch throughout the body
107
The largest tubes of the tracheal system
Tracheae
108
Unlike tracheal systems, which branch throughout the insect body, lungs are localized respiratory organs.
True
109
Trachea (mammals)
Windpipe
110
Larynx
The upper part of the respiratory system. Contains the vocal cords
111
Glottis
The opening of the trachea
112
If the glottis is open, it enables breathing
True
113
Bronchus (bronchi)
One of a pair of breathing tubes that branch from the trachea into the lungs
114
Bronchiole
A fine branch of the bronchi that transports air to alveoli
115
Alveoli
Air sacs clustered at the tips of the tiniest bronchioles
116
Gas exchange in mammals occurs in ______
Alveoli
117
Surfactant
A mixture of phospholipids and proteins which coat the alveoli and reduces surface tension
118
Breathing
The alternating inhalation and exhalation of air
119
Positive pressure breathing
Inflating the lungs with forced airflow
120
Instead of alveoli, birds use ______. Birds take two cycles of inhalation and exhalation for the passage of air to reach the entire system
Parabronchi
121
Negative pressure breathing
Pulling, rather than pushing, air into lungs
122
During exhalation, the muscles controlling the thoracic activity _______, and the volume of the cavity is _______.
Relax, reduced
123
Inhalation is always active and requires work, whereas exhalation is usually passive
True
124
Diaphragm
A sheet of skeletal muscle that forms the bottom wall of the thoracic cavity
125
Tidal volume
The volume of air inhaled and exhaled with each breath
126
Vital capacity
The tidal volume during maximal inhalation and exhalation
127
Residual volume
The air that remains after a forced exhalation
128
Respiratory pigments
A protein that transports oxygen in blood or hemolymph
129
Bohr shift
Refers to when low pH decreases the affinity of hemoglobin for O2
130
Myoglobin
Oxygen-storing protein in diving mammals
131
Thorough-fare channels
Capillaries that transport blood from arterioles to venules; they are always open.
