BIOS 214 Lecture Notes - Lecture 16: Portal Vein, Hepatic Veins, Middle Colic Artery
72
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he
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rn
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an impulse
fr
om within in the SA node (o
fa
nonnally functioning heart).
The
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nn
onal
co
ntrol
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nght and le
ft
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ndle brances
Purkin Je
fi
bers
E l
pi
foci
Hean Blocks
Animation of rdia
C'
ondu tion y. tern.
lX.
The
Electrocardiogra
m (ECG)
A. ECG --depolarization and repolari
za
ti
on
of
the cardiac
mu
scle
s:
l . stimulus is action potential
2. role
of
the intercalated disks?
3.
Depolarization
--before
co
ntraction
4. positive
pole
of
ECG
--right arm
5. negative pole
of
ECG --left leg
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a)
The
P-wave-- depolarization prior to atrial contraction
b)
The
QRS
compl
ex -
-d
epolarization associated
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u
~~
, d a
triaJ~o
·zation
ck
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l
L2
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c)
T-wave-- repolarizatio
no
fth
eventricles
r-
P.
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->
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X. Regulation
of
the Cardiac Cycle
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<.(o
{)
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,:
r _ 0
A.
INFLUENCES
ON
SA
NOD
E -
~J
--
~
___
-
-,..
i(
.,VI
l )
...JLO
t':
&1
l .
Post
ganglionic parasympathetic nerve fibers secrete acetylcholine --inhibito
ry
V\.t
\J
-{{
(
2.
Post
gangli
on
ic sympathetic nerve fibers are adrenergic and secrete norepinephrine --acceleration 1
3.
Both
controlled by cardiac centers in the medulla oblongata ' t
{:
B .
Sensory
input for regulati
on
of the cardiac cycle is received from:
1.
Aortic
/carotid stretch receptors-- inhibito
2.
Stretch
receptors in afferent ve
ss
els stimulatory PQ
RS
T 7
~
1
.::
,
3.
Emo
tional sta
te
s--anxiety accelerates, depression
de
ccelerates
4. se
lf
-regulation
XI. Special Circulations--Bepat
ic
Portal System -
591
1.
The
liv
er
re
ce
ives blood from two so
ur
ces:
a.
Hepa
tic artery
b. hepatic portal
ve
in-
portal
sy
stem
--a
capillary b
ed
at EACH end of a vein.
2. Veins w
hic
h contribute to formation
of
the hepat
ic
portal vein:
a. Superi
or
mesenteric (ileocolic, right and middle colic)
b. Splenic (left
ga
stroepiploic, pancreatic
c. Inferior
mes
enteric (large intestine)
(Lef
t colic and superior rectal, sigmoid)
3. Bl
ood
leaves
th
e li
ver
through t
he
hepatic veins which join the inferior vena cava.
XII. S
pecia
l
Circu
l
ati
on
s-
V
er
tebral-Basilar
Svstem
p
599
Supplies
the
brainstem, parts
of
the
cereb
01m
Spinal
e<fr
d
Verteb
ra
l
art
e
ri
es
unite to form Basil
ar
( an
t.
Surface
of
pons)
•
1n
r n·or Cerebellar
Artery
(PICA) from each vertebral just prior to union
P
os
ten
or
ie
- . . . -
l.
•-r
· r surface
of
cerebellar hemispher , choroids plexus lateral medulla
Supp
1e
s tru.eno
(cttO
·~
