1. Rapid Control of Arterial
Pressure by Nervous System
By:
M. Rasjad Indra
Lab. Ilmu Faal FK UNIBRAW

2. Pengendalian sirkulasi oleh sistem
saraf
Peran sistem saraf dalam pengendalian
aliran darah lokal sangat kecil.
Sistem saraf lebih berperan pada fungsi
global dalam hal:
1. Pendistribusian darah ke area tubuh tertentu
2. Kekuatan pompa jantung
3. Pengendalian cepat tekanan darah

3. Three Major Changes
 If sympathetic nervous system are stimulated
1. Almost all arterioles are constricted
• Increases the total peripheral resistance
1. The veins especially & other large vessels are
strongly constricted
• Increases venous return increase cardiac out put
(Starling Law)
1. The heart enhancing cardiac pumping
• Increases heart rate
• Increases cardiac contractility

4. Anestesi spinal menyebabkan penurunan tekanan darah akibat
hilangnya tonus vasomotor

5. Reflex Mechanism for Maintaining
Normal Arterial Pressure
Baroreceptor Reflexes:
– The receptors: Baroreceptors or Pressoreceptors
Located in the wall of several of large systemic
arteries
Sinus caroticus n. Hering n. Glossopharyngeus 
tr. Solitarius Med. Oblongata.
Arcus aortae n. Vagus
– The Response: Feedback signals to reduce
arterial pressure
Vasodilatation of the veins and arterioles
Decreased heart rate & the strength of heart
contraction

6. Efek perubahan tekanan arteri (ΔP) terhadap perubahan transmisi impuls
n. Hering dari sinus Caroticus ( ΔI)
Baroreseptor lebih merespons perubahan tekanan daripada tekanan
stasioner

7. Penjepitan a. carotis communis menyebabkan peningkatan tekanan
arteri (MAP), pelepasan jepitan menurunkan tekanan arteri

8. Function of Baroreceptor Reflex
During changes in Body Posture
– To maintain relatively constant arterial
pressure in the upper body
Pressure Buffer Function
– Opposes either increases or decreases in
arterial pressure.
Unimportance of Baroreceptor System for
Long Regulation
– The resetting of baroreceptor systems

9. Pencatatan tekanan darah selama 2 jam pada kondisi NORMAL (gambar atas)
dan pada beberapa minggu setelah DENERVASI sinus caroticus
dan Sinus aorticus

10. Frekuensi distribusi MAP selama 24 jam pada anjing NORMAL dan beberapa
minggu setelah denervasi baroreseptor

11. Reflex Mechanism for Maintaining Normal
Arterial Pressure (Cont.)
Chemoreceptors Reflex:
– The receptors sensitive to:
Lack of oxygens; CO2 excess and H+ excess.
Located in the wall of small arteries; Carotid Bodies & Aortic
Bodies.
– Not a powerful control in a normal arterial pressure
range
Important in below 80 mmHg
Low-pressure Receptors:
– Stretch receptors
– Located in the wall of: Pulmonary arteries & Atrium
– Role: to minimize arterial pressure changes in
response to changes in blood volume.

12. Reflex Mechanism for Maintaining
Normal Arterial Pressure (Cont.)
Volume Reflex (Atrial Reflex that Activate the Kidney)
– Stimulation: Stretch of the atria
– Response:
1. Dilatation of the afferent arteriole in the kidney
2. To Hypothalamus  Decrease ADH secretion
3. Release of Atrial Natriuretic Peptide (ANP)
The Bainbridge Reflex
– Stimulation: Stretch of the atria
– Response: n. Vagus Med. Oblongata Increase the
heart rate & strength of the heart contraction

13. BARORESEPTOR
HIGHER CENTER
CONTROL “Blood Pressure”
CA
CI
VASOMOTOR
CENTER
“Baroreceptor” +
CI CA
+ -
JANTUNG
SV Hr
C.O.P CHEMORECEPTOR
X
VD TPR VC H PH
O2 CO2
“Blood Pressure”