Circulation

What lack a circulatory system?

Platyhelminthes

The open circulatory system is a system in which a fluid in a cavity called _________ bathes the organs directly with oxygen and nutrients and there is no distinction between blood and interstitial fluid.

the Hemocoel

Combined fluid in Hemocoel

Hemolymph (or Haemolymph)

Hemolymph is composed of water, _________ (mostly Na+, Cl-, K+, Mg+2, and Ca+2), and organic compounds (mostly carbohydrates, proteins, and lipids).

inorganic salts

The primary oxygen transporter molecule of hemolymph is what?

Hemocyanin

Hemocyanins are _________ that transport oxygen throughout the bodies of some invertebrate animals.

proteins

Hemocyanins are _______ that contain two copper atoms which will reversibly bind a single oxygen molecule (O2).

metalloproteins

Oxygenation causes a color change between the colorless Cu(I) deoxygenated form and the ______ Cu(II) oxygenated form.

blue

There are free-floating cells called ________, within the hemolymph. These cells play a role in the arthropod immune system

Hemocytes

Muscular movements by the animal during locomotion can facilitate hemolymph movement, but diverting flow from one area to another is limited. When the heart relaxes, blood is drawn back toward the heart through open-ended pores called what?

Ostia

The hemocoel can be a large portion of the animal’s body and may constitute ___________ of the body volume.

20% - 40%

Generally animals with open circulatory systems have a _______ ability to alter the velocity and distribution of hemolymph flow.

limited

Who has a tracheal system is a series of air filled, tubular organs that transport respiratory gases directly to the animal’s tissues.

insects

The circulatory systems of all vertebrates, as well as of certain invertebrates such as annelids and cephalopods, are ______.

closed

In most fish, the system has only one circuit, with the blood being pumped through the capillaries of the gills and on to the capillaries of the body tissues. This is known as _______ Unit Circulation.

Single

The heart of fish is only a single pump (consisting of ______ chambers).

two

In amphibians and most reptiles, a developing _______ Unit Circulatory system is used, but the heart is not always completely separated into two pumps.

Double

The blood is sent by the heart into ____.

Arteries

Arteries handle blood under its ______ pressure.

highest

The system of arteries serves as a acts as a pressure reservoir, sending blood into what?

The capillaries

What are thin walled vessels that allow for an exchange of materials between the blood and the tissues of the body?

Capillaries

In vertebrates the fluid that escapes from the capillaries is recovered by a _________, cleansed of pathogens, and returned to venous circulation.

Lymphatic System

What collect blood from the capillaries and returns it to the heart?

Veins

Veins handle blood under _______ pressure than do arteries.

lower

Veins are also ________, and as a result, large changes in blood volume have little effect on venous pressure.

flexible

What allows the veins to act as a reservoir for blood.

Venial flexbility

The clinical term for a contraction of a heart chamber is what?

Systole

The clinical term for a relaxation of a heart chamber is what?

Diastole

Electrical activity initiated by the pacemaker region of the heart will spread throughout the heart from one myofiber to the next by specialized junctions called what?

Intercalated Discs

The ________ of the heart will initiate the heartbeat.

pacemaker

Neurogenic pacemakers are found in a number of ________ such as the decapod crustaceans (lobsters, crabs, and shrimp).

invertebrates

There will be a cluster of perikarya situated on the heart called what?

Cardiac Ganglion

Pacemaker: The small cells are the ________ cells.

pacemaker

Pacemaker: What will initiate the heartbeat by stimulating the larger cell type.

pacemaker cells

Pacemaker: The larger cells, sometimes referred to as “________”, will have axons that travel through the heart wall.

follower cells

Pacemaker: When stimulated by the pacemaker cells they will send a wave of depolarization through the heart chamber causing systole to occur.

follower cells

When the heart enters into diastole blood is drawn back into it through what?

ostia

Myogenic pacemakers are found in some invertebrates (ex; mollusks) and what?

vertebrates

It is the _________ myofibers that act as the pacemaker of the heart and distribute the impulse throughout the heart wall.

conductive

Myogenic pacemakers: These conductive cells are found in clusters, referred to as __________, and come in two forms: large branching cells that will distribute the impulse throughout the heart, and smaller cells that are coupled with the larger type and will initiate the contraction.

Nodal Tissue

Myogenic pacemakers: ________ branching cells that will distribute the impulse throughout the heart.

Large

Myogenic pacemakers: Smaller cells that are coupled with the larger type and will initiate what?

contraction

Whether the cells are part of a neurogenic or a myogenic pacemaker they all share the characteristic of lacking what?

A stable resting potential

After each action potential the cell membrane of the pacemaker cell will undergo a steady depolarization, called what?

Pacemaker Potential

The pacemaker potential will quickly bring the cell membrane back to the _______ potential.

threshold

Conductive cells contain a series of sodium ion channels that allow a normal and slow influx of sodium ions that causes the membrane potential to rise slowly from an initial value of −60 mV up to about _______ mV.

–40

Cardiac Potential: The resulting movement of sodium ions creates spontaneous depolarization (or prepotential depolarization). This phenomenon explains the _________ properties of cardiac muscle.

autorhythmicity

________, a neurotransmitter produced by the parasympathetic division of the vertebrate ANS, will slow the heart rate.

Acetylcholine

When Acetylcholine is released by the vagus nerve at the SA node (in vertebrates) it will cause an increase in _____ conductance. and a decrease in Ca+2 conductance by the pacemaker cells.

K+

______ will also slow the heart rate in a mechanism similar to acetylcholine.

Adenosine

_________ released by the sympathetic division of the ANS will speed up the heart rate by accelerating the pacemaker potential.

Norepinephrine

Norepinephrine released by the ____________ division of the ANS will speed up the heart rate by accelerating the pacemaker potential.

sympathetic

Acetylcholine, a neurotransmitter produced by the __________ division of the vertebrate ANS, will slow the heart rate.

parasympathetic

Acetylcholine released by the _________ at the SA node (in vertebrates) itwill cause an increase in K+ conductance. and a decrease in Ca+2 conductance by the pacemaker cells.

vagus nerve

Norepinephrine will bind to ____________ on the pacemaker cell membrane.

b-adrenoreceptors

Another difference is that the action potentials preceding a cardiac myofiber contraction are of a _______ duration than are those preceding a skeletal myofiber contraction.

longer

Cardiac muscle is a _______ in which the cardiac muscle cells are so tightly bound that when one of these cells is excited the action potential spreads to all of them

Syncytium

In most cardiac contractile myofibers action potentials begin with a rapid depolarization which will result from a rapid and large increase in ______ conductance.

Na+

The repolarization of the cardiac sarcolemma is delayed for hundreds of milliseconds during what is termed what?

Plateau Phase

electrical events: represents the depolarization of the atria.

P wave

P wave is considered to be the ______ point of the cardiac cycle.

starting

Atrial cells generally have a _______ lasting action potential than do those of the ventricles.

shorter

electrical events: represents the depolarization of the ventricles.

QRS wave

During the QRS wave, the atria are _______ but that electrical signature is obscured by the much greater electrical discharge of ventricular contraction.

repolarizing

electrical events: represents the repolarization of the ventricles.

T wave

electrical events: is hypothesized to be caused by the repolarization of theinterventricular septum.

U wave

During development of the vertebrate embryo the ANS nerves will grow to what?

sinus venosus

Birds and _____ lose the sinus venosus during development.

mammals

the sinus venosus in mammals will remain only as a mass of nodal tissue in the right atrium called what?

Sinoatrial Node

The SA node will also stimulate (simultaneously) another cluster of nodal tissue called what?

Atrioventricular Node

Heart: Due to the greater muscle mass of the ventricles fibrous strands of nodal tissue will run through the ventricles to improve the efficiency of conduction. These strands include what?

Purkinje Fibers

catecholamines epinephrine and norepinephrine increase the heart rate of by increasing the rate of myocardial contraction.

Positive Chronotropic Effect

catecholamines epinephrine and norepinephrine increase the force of myocardial contraction

Positive Inotropic Effect.

catecholamines epinephrine and norepinephrine increase the speed of conduction of the impulse, or wave of excitation, throughout the heart

Positive Dromotropic Effect

Defined as the volume of blood being pumped by the heart, typically either the right or left ventricle, in a time interval of one minute.

Cardiac Output

Defined as the blood ejected from a ventricle during each heartbeat.

Stroke Volume

Stroke Volume (SV) is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat (called ________) from the volume of blood just prior to the beat (called End-Diastolic Volume).

End-Systolic Volume

Stroke Volume (SV) is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat (called End-Systolic Volume) from the volume of blood just prior to the beat (called _______).

End-Diastolic Volume

Cardiac output is the product of stroke volume and heart rate. Equation?

CO = SV * HR

What is the speed of the heartbeat measured by the number of heartbeats per unit of time; typically beats per minute (bpm)?

Heart Rate

Birds and adult mammals lack a _______. Instead its blood vessels drain directly into the right atrium.

sinus venosus

The ancestral location of the sinus venosus in mammals is marked by the location of what?

sinoatrial node

During embryonic development the interatrial septum is perforated by an opening called what?

Foramen Ovale

In mammals the adult heart maintains a depression on the interatrial septum, called the ________, where the foramen ovale once was located.

Fossa Ovalis

The right atrium receives ________ blood.

deoxygenated

What vessels delivery deoxygenated blood to heart?

Superior and Inferior Vena Cava

The left atrium receives oxygenated blood from the lungs by way of what?

Pulmonary Veins

The atria in mammals have outpocketings called what?

Auricles

Some reptiles, in particular turtles and Squamates, have a third ventricle called the _______ near the superior axis of the interventricular septum.

Cavum Venosus

The cavum venosus helps to _____ oxygenated from deoxygenated blood.

shunt

In ______ all heart chambers have cardiac muscle.

amniotes

The Mammalian Fetal Heart: During gestation the fetus receives all of its oxygen through what?

placenta

The Mammalian Fetal Heart: The pulmonary artery is joined to the aortic arch by a fetal blood vessel called what?

Ductus Arteriosus

Placental blood enters the heart through the posterior vena cava. On the interatrial septum of the fetal heart is an opening called the what?

Foramen Ovale

The foramen ovale allows the ________ blood from the placenta to enter into the left atrium.

oxygenated

Blood Vessels: The Innermost is the ___________ which is in direct contact with the blood.

Tunica Intima/Tunica Interna

Blood Vessels: The second tunic is the Tunica ________.

Media

Blood Vessels: This tunic will contain smooth muscle.

Tunica Media