Circulatory System

what is a circulatory system?

how organisms deliver oxygen and nutrients to tissues

what is simple diffusion?

passive movement of dissolved substances due to concentration gradient

list the organisms that do not have circulatory systems

- kingdom archaea
- kingdom eubacteria
- kingdom protista
- kingdom fungi
- kingdom animalia
1) porifera
2) cnidaria
3) platyhelminthes
4) nematoda
5) rotifera

how is hemolymph pumped in an insects body?

tubular hearts pump fluid through a single dorsal vessel --\> sinuses --\> hemocoel

what causes hemolymph to be moved around within the hemocoel?

locomotion and muscular contractions

how does hemolymph re-enter a relaxed insect heart?

ostia

\_____ allow air to pass into the tracheal system of insects

spiracles

list the invertebrate animals with an open circulatory system

kingdom animalia
1) mollusca
2) arthropoda
3) echinodermata

\_____ is fluid that allows gas exchange in closed circulatory systems

blood

list the invertebrates with a closed circulatory system

annelida (segmented worms)

segmented worms (aka annelids) have multiple hearts called \_____, which pump blood in a circuit

aortic arches

what are the primary

true heart chambers?

atria and ventricles

what are the two primary chambers of two-chambered hearts?

one atrium and one ventricle

two-chambered hearts only pump \_____ blood

deoxygenated

two-chambered hearts are \_____ (single/double) circulation hearts

single

what is a common example of an organism that has a two-chambered heart?

fish

ventricles are (stronger/weaker) than atria - why?

stronger; ventricles pump blood out to the body, while atria only pump blood into the ventricle directly attached to it

what are the three primary chambers of three-chambered hearts?

right and left atrium; single ventricle

three-chambered hearts mix deoxygenated and oxygenated blood in the \_____

ventricle

three-chambered hearts are \_____ circulation hearts

double

what types of animals have three-chambered hearts?

poikilothermic amphibians and reptiles

what are the four primary chambers of four-chambered hearts?

left and right atrium; left and right ventricle

why does the blood not mix in four-chambered hearts?

because there are two separate ventricles for the deoxygenated and oxygenated blood

four-chambered hearts are \_____ circulation hearts

double

what type of animals have four-chambered hearts?

birds and mammals (homeothermic chordates)

the right atrium accepts \_____ (oxygenated/deoxygenated) blood from the vena cava

deoxygenated

blood pumps from the right atrium to the \_____ through the \_____

right ventricle; tricuspid (atrioventricular) valve

what is the right atrioventricular valve also known as and why?

tricuspid valve; it has three cusps (flaps)
Mnemonic

what are the largest veins in the human body and to what do they connect?

vena cava; the right atrium

what returns deoxygenated blood from above the heart?

superior vena cava

what returns deoxygenated blood from below the heart?

inferior vena cava

what prevents backflow from the ventricles to the atria?

atrioventricular valves (AV valves)

AV valves close when which muscles contract?

papillary muscles

what are the stringy tendons that attach papillary muscles to AV valves?
chordae tendineae

the right ventricle pumps deoxygenated blood to pulmonary arteries through which valve?

pulmonary semilunar valve

semilunar valves have \_____ cusps

3

\_____ valves ensure one-way flow of blood from ventricles to arteries

semilunar

the \_____ take deoxygenated blood from the right ventricle to the lungs for gas exchange

pulmonary arteries

what are the vessels moving away from the heart?

arteries

\_____ return oxygenated blood to the left atrium after gas exchange at the lungs

pulmonary veins

what are the vessels that carry blood toward the heart?

veins

oxygenated blood flows from the left atrium to the left ventricle, through the \_____

bicuspid/mitral valve

the bicuspid/mitral (AV) valve has \_____ to ensure unidirectional blood flow from the left atrium to left ventricle

two cusps/flaps

the \_____ is the most muscular chamber of the heart

left ventricle

the left ventricle forcefully ejects oxygenated blood through the \_____ valve into the \_____

aortic semilunar; aorta

the \_____ is the largest artery

aorta

from where does the aorta leave the heart?

left ventricle

the aorta has the highest \_____ of any vessel

blood pressure

what are the two circulations of the human cardiac system?

pulmonary; systemic

\_____ circulation moves deoxygenated blood to the lungs for oxygenation

pulmonary

what is the pathway for pulmonary circulation?

vena cava --\> right atrium --\> tricuspid valve --\> right ventricle --\> pulmonary semilunar valve --\> pulmonary arteries --\> lung --\> pulmonary veins --\> left atrium

\_____ circulation moves oxygenated blood to the body tissues

systemic

what is the pathway for systemic circulation?

left atrium --\> bicuspid

mitral valve --\> left ventricle --\> aortic semilunar valve --\> aorta --\> body tissues --\> vena cava --\> right atrium

does systemic or pulmonary circulation have a higher resistance to blood flow?

systemic

how does the heart pump blood to itself?

coronary circulation

what is the muscular layer of the heart

myocardium

what are the cells contained in the myocardium?

cardiomyocytes

what type of cells line the inside of the heart?

endothelial

the \_____ lies beneath the myocardium

endocardium

\_____ drain deoxygenated blood from the myocardium to the right atrium via the coronary sinus

cardiac veins

what is the small opening in the right atrium that cardiac veins empty into?

coronary sinus

the \_____ is a protective sack of fluid surrounding the heart

pericardium

what is the fluid in the pericardium?

serous fluid

cardiomyocytes have automaticity - what does that mean?

action potentials will generate without external nerves having to initiate the action potential

the \_____ is the pacemaker of the heart

sinoatrial node (SA node)

which part of the heart has the greatest automaticity?

the SA node

where is the SA node located?

right atrium

which nervous system causes the heart's beating pace to increase and which causes it to decrease?

sympathetic; parasympathetic

the \_____ extends from the medulla oblongata and innervates the SA node

parasympathetic vagus nerve

the parasympathetic vagus nerve sends a default signal to \_____ (slow down/speed up) the SA node automaticity to \_____

slow down; 60-90 BPM

what is a tachycardic heart rate?

\> 100 BPM

what is a bradycardic heart rate?

< 60 BPM

what is the function of the AV node?

add a brief delay between atrial and ventricular contractions
where does the AV node conduct to?

where is the bundle of His located?

interventricular septum

what does the bundle of His do?

carries the signal to the base of the heart

purkinje fibers are located in the walls of the \_____

ventricles

what is the function of the Purkinje fibers?

they ensure a coordinated contraction of both ventricles

\_____ receive conduction from the bundle of His

purkinje fibers

what is the name for the period of time right after the ventricles eject their blood?

systole

systole is the phase where blood pressure is \_____ (highest/lowest)

the highest

what is the period of time right after the atria contract to fill the ventricles?

diastole

the myocardium is \_____ (relaxed

contracted) during diastole

relaxed

diastole is the phase where blood pressure is the \_____ (highest/lowest)

lowest

atria are relaxed during the \_____ (lub/dub) heart sound

"lub"

\_____ are contracting during the "lub" heart sound

ventricles

\_____ are contracting during the "dub" heart sound

atria

ventricles are relaxed during the \_____ (lub/dub) heart sound

"dub"

when does systole occur (sounds)?

between lub and dub

when does diastole occur (sounds)?

after dub (before next lub)

which side of the heart is stronger - left or right?

left

why is the left side of the heart stronger than the right side?

systemic circulation and greater vascular resistance

\_____ are contact points between adjacent cardiomyocytes

intercalated discs

\_____ 'stitch' cardiomyocytes together at intercalated disks

desmosomes

\_____ are protein tunnels that connect adjacent cardiomyocytes

gap junctions

gap junctions are involved with \_____ transport

molecule/ion

\_____ allows the heart to function in unity

cardiac syncytium

what is the wave that represents both atria depolarizing?

p wave