Chapter 42, Part I (Circulation) Study Guide
Vertebrate Hearts
Fish
# Atria; #
Ventricles
Total Chambers
Frog
1; 1
Bird
2; 1
2; 2
Mammal
2; 2
2
3; Ventricle splits
4
4
blood to both
circuits
Circuits Present;
Gill circulation;
Pulmocutaneous;
Pulmonary;
Pulmonary;
types
systemic
systemic
systemic
systemic
circulation
circulation
Mixing of O2
No
Yes; Double
No
No
rich/poor blood
circulation
 More heart chambers allows higher metabolic rate because of less mixing of oxygenated and deoxygenated1 blood, more powerful heart, ability to pump more blood
 2 chambered heart limits metabolic rate because heart must pump through 2 capillary beds, pressure
reduced at each bed; 3 & 4 chambered hearts pump heart → capillary bed → heart → bed → heart
 Ridge in 3 chambered heart diverts most deoxygenated blood to lungs ( blood doesn’t mix
completely)
Open vs. Closed Circulatory Systems
Open
 Blood = interstitial fluid
(Hemolymph)
 Blood bathes organs directly via
sinuses
 Ex. Insects, arthropods
Closed
 Blood is separate from
interstitial fluid
 Heart pumps blood into large
vessels that branch into smaller
ones
 Diffusion exchanges materials
through smaller vessels
 Ex. Earthworms, squids,
octopuses, vertebrates
Both
 Blood
 Blood vessels
 Heart
Blood Vessels: Arteries, Veins, Capillaries
Arteries
Direction of blood flow Away from heart
Location in body
Carries towards organs
General structure;
 Endothelium (inner
thickness
lining), smooth muscle,
connective tissue
 Thicker middle/outer
layers than veins
(higher pressure)
 High, uneven pressure
Elastic?
Yes
Function in circ.
Carry blood to organs
system
1
Veins
Towards heart
Carries away from organs
 Endothelium (inner
lining), smooth muscle,
connective tissue
 Low, even pressure
 Has valves to prevent
backflow into capillary
beds
Yes
Return blood to heart by
skeletal muscle action
Blood is never truly “de-oxygenated”, this term is used to describe poorly oxygenated blood
Capillaries
Connects arteries & veins
Within organs
 Endothelium (inner
lining), basement
membrane
 very narrow
No
Diffusion of substances
to/from organs
Components of Blood: WBC, RBC, Platelets, Plasma
WBC (leukocytes)
RBC (erythrocytes)
Platelets
Function(s)
 Defense; fight
infections
Where
produced
How/why
regenerated
 Transport oxygen
 Clotting
———— Bone marrow; ribs, vertebrae, breast bone, pelvis ————
Plasma
 Osmotic balance
 pH buffering (7.4)
 clotting
 defense
Mostly water (see
below)
Pluripotent stem
cells →Myeloid stem
cells
Only last 3-4 mos.;
Pluripotent stem
cells →Myeloid stem
cells; erythropoietin
stimulates RBC
production
Cytoplasmic
fragments of cells in
bone marrow
Kidneys regulate
concentration of
ions/water
< 1% of all blood
42% of all blood
3% of all blood
55% of all blood
No
Yes, more space for
hemoglobin
Yes b/c fragments of
cells
Yes b/c not cells
% composition by
volume
Cell
organelles
lacking?
Key Terms
Circulation
ABO blood
groups
Genetically determined classes of human blood that are based on the presence or
absence of carbohydrates A and B on the surface of red blood cells. The ABO blood
group phenotypes, also called blood types, are A, B, AB, and O.
acetylcholine
One of the most common neurotransmitters; functions by binding to receptors and
altering the permeability of the postsynaptic membrane to specific ions, either
depolarizing or hyperpolarizing the membrane.
adrenaline
arteriole
arteriosclerosis
artery
Hormone, aka epinephrine; produced in respone to stress; increases HR
A vessel that conveys blood between an artery and a capillary bed.
A cardiovascular disease caused by the formation of hard plaques within the arteries.
A vessel that carries blood away from the heart to organs throughout the body.
Atrioventricular A region of specialized muscle tissue between the right atrium and right ventricle. It
(AV) node
generates electrical impulses that primarily cause the ventricles to contract.
basophils
cardiac cycle
A circulating leukocyte that produces histamine.
The alternating contractions and relaxations of the heart.
countercurrent
exchange
The opposite flow of adjacent fluids that maximizes transfer rates; for example, blood in
the gills flows in the opposite direction in which water passes over the gills, maximizing
oxygen uptake and carbon dioxide loss.
diastole
The stage of the heart cycle in which the heart muscle is relaxed, allowing the chambers
to fill with blood.
dissociation
A chart showing the relative amounts of oxygen bound to hemoglobin when the
curve
pigment is exposed to solutions varying in their partial pressure of dissolved oxygen.
erythrocytes
A red blood cell; contains hemoglobin, which functions in transporting oxygen in the
circulatory system.
fibrin
The activated form of the blood-clotting protein fibrinogen, which aggregates into
threads that form the fabric of the clot.
fibrinogen
The inactive form of the plasma protein that is converted to the active form fibrin,
which aggregates into threads that form the framework of a blood clot.
hemoglobin
An iron-containing protein in red blood cells that reversibly binds oxygen.
hemolymph
In invertebrates with an open circulatory system, the body fluid that bathes tissues.
hypertension
High blood pressure
interstitial fluid
lymphocytes
medulla
The internal environment of vertebrates, consisting of the fluid filling the spaces
between cells.
A white blood cell. The lymphocytes that complete their development in the bone
marrow are called B cells, and those that mature in the thymus are called T cells.
Also called the medulla oblongata, it is the lowest part of the vertebrate brain; a
swelling of the hindbrain dorsal to the anterior spinal cord that controls autonomic,
homeostatic functions, including breathing, heart and blood vessel activity, swallowing,
digestion, and vomiting.
monocytes
An agranular leukocyte that is able to migrate into tissues and transform into a
macrophage.
myoglobin
An oxygen-storing, pigmented protein in muscle cells.
neutrophils
The most abundant type of leukocyte. Neutrophils tend to self-destruct as they destroy
foreign invaders, limiting their life span to but a few days.
peripheral
resistance
plasma
The impedance of blood flow by the arterioles.
The liquid matrix of blood in which the cells are suspended.
platelets
A small enucleated blood cell important in blood clotting; derived from large cells in the
bone marrow.
Rh factor
A category of erythrocyte antigen that generates antibodies of the IgG class.
semilunar valve
A valve located at the two exits of the heart, where the aorta leaves the left ventricle and
the pulmonary artery leaves the right ventricle.
sinatrial (SA)
node
The pacemaker of the heart, located in the wall of the right atrium. At the base of the
wall separating the two atria is another patch of nodal tissue called the atrioventricular
node (AV).
systemic
circulation
The branch of the circulatory system that supplies all body organs and then returns
oxygen-poor blood to the right atrium via the veins.
systole
The stage of the heart cycle in which the heart muscle contracts and the chambers
pump blood.
vein
venule
A vessel that returns blood to the heart.
A vessel that conveys blood between a capillary bed and a vein.