DAT bio Chapter 11, circulatory system Flashcards
No circulatory system
use simple diffusion
to distribute nutrients. Includes bacteria,
protista, fungi, invertebrate animals.
Open circulatory system –
– pumps fluid called
hemolymph into sinuses or hemocoel.
Includes some mollusca, arthropoda,
Echinodermata.
Closed circulatory system
Use a pumping
heart to move blood through vessels. Includes
annelida (earthworms)
Most chordates (eukaryotic vertebrates within kingdom Animalia) have what kind of a system
closed circulatory system
● 2-chambered hearts is composed of?
atrium and ventricle-(fish)
Deoxygenated blood fills the heart and is pumped
to the gills for oxygen exchange.
3-chambered hearts is composed of?
(2 atriums and 1 ventricle)-amphibians and reptiles which are poikilothermic chordates.
Ventricles are stronger than atria T.F
True
4-chambered hearts is composed of
2 atriums and 2 ventricles- birds and humans. which are homeothermic chordates
Flow of blood through heart
Step 1
Right atrium
Deoxygenated blood is returned
here from the upper superior vena cava and
the lower inferior vena cava. Blood passes
through the right atrioventricular valve (AV
valve, or tricuspid valve) to the right
ventricle. AV valve is attached to papillary
muscles, which contract to close the AV valves
and prevent backflow of blood.
Flow of blood through heart
Step 2
Right ventricle
Pumps deoxygenated blood
through the pulmonary semilunar valve to the
pulmonary artery. Blood enters pulmonary
circulation. When the ventricle contracts, the
AV valve is closed and the pulmonary
semilunar valve is open. When the ventricle
relaxes, the AV valve is open to refill the
ventricle, and the pulmonary semilunar valve
closes to prevent the backflow of blood.
Flow of blood through heart
Step 3
left atrium
Oxygenated blood is returned
here from the lungs from the pulmonary vein.
Blood passes through the left AV valve (or
bicuspid, or mitral valve) to the left ventricle.
Flow of blood through heart
Step 4
left ventricle
– Most muscular chamber of
the heart. Pumps oxygenated blood into the
aorta and systemic circulation.
What is pulmonary circulation?
moves deoxygenated
blood from heart to the lungs and back in order
for it to become oxygenated.
Pathway for pulmonary circulation
Right atrium → tricuspid valve →
right ventricle → pulmonary semilunar valve →
pulmonary arteries → lung → pulmonary veins → left
atrium
What is systemic circulation
moves oxygenated blood
from the heart throughout the body.
systemic circulation pathway
Left atrium → bicuspid / mitral valve → left
ventricle → aortic semilunar valve → aorta → body
→ vena cava → right atrium
- The SA node (pacemaker)
- location
- function
1) located in the
upper wall of the right atrium
2) initiates the cardiac cycle.
3) It sends a
signal to contract both atria to send blood to
the ventricles. It also sends a signal to the AV
node to initiate contraction.
Which part of the cardiac cycle has the most automaticity? (are self-excitable
and able to initiate an action potential without an
external nerve.)
SA node
most likely to reach
threshold to stimulate a heartbeat.
The AV node
- location
- function
1) lower wall of the
right atrium.
2) function of the AV node is to
add a brief delay between the contraction of
the atria and the contraction of the ventricles.
What kind of signal is sent by the AV node?
also sends a signal to the bundle of His,
located in the interventricular septum
between the ventricles. The bundle of His
carries the signal to the Purkinje fibers, which
contract the ventricles.
When does Systole happen?
occurs right after the ventricles eject their
blood into the arteries they connect to. Therefore,
it is the phase of the cardiac cycle where blood
pressure is highest in the arteries.
When does diastole happen?
occurs right after the atria contract to fill
the ventricles. The myocardium is completely
relaxed at this point. Diastole is the phase of the
cardiac cycle where blood pressure is lowest in the
arteries.
Heart beat sound is described as
lub dub
Lub stands for
The atria are relaxed, while the
ventricles are contracting. The noise
comes from the AV valves snapping shut
as the ventricles contract.
Dub stands for
The atria are contracting, while the
ventricles are relaxing. The noise comes
from the semilunar valves snapping
shut.
Systole happens ____ the lub-dub sounds.
Diastole occurs between the dub and ___ lub
sound.
between
next
What is Signal transduction
The heart has intercalated discs that connect
adjacent heart cells (cardiomyocytes). Intercalated
discs are made of desmosomes and gap junctions
and function to transmit the signal to contract in a
coordinated, rhythmic fashion.
What is heart rate
is how fast the heart beats.
Tachycardia is greater than 100 beats per minute,
bradycardia is less than 60 beats per minute.
What is Stroke volume (SV)
the volume of blood
pumped from the heart with each beat. Stroke
volume is calculated by subtracting end-systolic
volume from end-diastolic volume.