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Animal Physiology Test 3 Chapter 12
N/A
33
Biology
Undergraduate 3
04/15/2014

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Term
Structural properties of the circulatory system (4)
Definition
A main propulsive organ
High speed delivery: arterial system
Exchange system: capillaries
Return: venous system
Term
Functional properties of the circulatory system (4)
Definition
Forces imparted by rhythmic contractions of the heart
Elastic recoil of arteries following filling by heart
Squeezing of blood vessels by body movements (skeletal muscle contractions)
Peristaltic contractions of smooth muscle of the vessels.
Term
Open circulatory system
______ circulates through vessels which open to a space called ________.
Definition
hemolymph
hemocoel
Term
ECF vs circulatory fluid in an open circulatory system
Definition
No distinction between ECF and circulatory fluid.
Term
Hemolymph contains
Definition
respiratory proteins
Term
Most, though not all of the invertebrates have a ______ circulatory system
Definition
open
Term
The closed circulation of cephalopods is characterized by a _____ blood pressure and _____ efficient delivery of oxygen compared with open circulatory system
Definition
higher
more
Term
The closed circulatory system in mammals includes a full divided ______, which permits different ______ to be maintained in the pulmonary and systematic circuits. The associated lymphatic system returns fluid from the extracellular space to the bloodstream via the
Definition
fully
pressures
thoracic duct
Term
The multi-chambered mammalian heart permits the pressure to ________ as blood moves from the venous to arterial . Impulses originate in the ________ region, located in the _________ node, and spread to the _______ node, from which they're transmitted to the _______.
Definition
increase
pacemaker
SA
AV
ventricles
Term
Two types of cardiac cells
Definition
contractile
electrical
Term
Contractile
Definition
force for pumping
Term
Electrical
Definition
conduction pathway
Term
6 characteristics of cardiac cells
Definition
-Sarcomere – striated tissue
-Single nucleus
-Intercalated disks – connected physically and electrically
-Branched
-Autorhythmic
-Large amount of mitochondria – resistant to fatigue
Term
Pacemaker potential
Definition
pacemaker cells undergo spontaneous depolarization of the membrane which triggers cardiac potential autorhythmically
Term
Parasympathetic stimulation via the _____ nerve and sympathetic stimulation have ______ effects on the pacemaker potential and heart rate.
Definition
vagus
opposite
Term
Vagus stimulation produces (3)
Definition
a rise in diastolic transmembrane potential
a decrease in the rate of depolarization
a decrease in duration and frequency of the action potential
Term
Sympathetic stimulation produces
Definition
an increase in the frequency of firing of the pacemaker cells
Term
Do action potentials differ in skeletal and cardiac muscle?
Definition
yes
Term
Action potentials in skeletal muscle duration
Definition
very short
Term
Cardiac action potential duration
Definition
a prolonged repolarization (plataeu phase) during which the muscle fiber is refractory to stimulation.

For this reason, repetitive stimulation during a contraction and summation of contractions can occur in skeletal muscles but not cardiac muscles
Term
1
APs in Contractile Myocardial Cells
Definition
Much longer AP
Refractory period and contraction end simultaneously
Term
2
Phase 0-1:
Definition
Depolarization due to voltage-gated Na+ channels
Term
3
Phase 1-2:
Definition
Partial Repolarization as Na+ channels close and some K transient current occurs (Kto channels)
Term
4
Phase 2 Plateau:
Definition
Ca2+ permeability (Ca2+L channels)
Term
5
Phase 3:
Definition
Repolarization: Back to resting potential due to gK (due to K channels open) and Ca2+ channels close
Term
Membrane potential of Myocardial Autorhythmic (pacemaker) Cells
Definition
-Fluctuates around – 60 mV
-More depolarized than most cells
Term
Unstable resting membrane potential (= pacemaker potential) due to
Definition
-Ca2+L and Ca2+T channels
-The cell membranes are “leaky”
-Unique membrane channels that are permeable to both Na+ and K+
Term
An electrocardiogram represents
Definition
the summation of the electrical activity in various parts of the heart
Term
P
Definition
atrial depolarization
Term
QRS
Definition
ventricle depolarization
Term
T
Definition
ventricle repolarization
Term
Do mammalian cardiac or skeletal muscles action potentials last longer?
Definition
cardiac
Term
Two ways valves promote unidirectional flow of blood
Definition
1. Open in one direction = Pressure gradient
2. Restrained by chordae tendinae attached to papillary muscles (during ventricular contraction)
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