SlideShare a Scribd company logo
Nervous Regulation of Circulation
Dr Shamshad
Majamaah University
Lecture 48
Objectives:
1. Describe the physiological anatomy of autonomic supply to
the heart & blood vessels.
2. Discuss the nervous control of circulatory functions esp.
heart rate.
3. Describe the role of vasomotor center in regulation of
circulatory functions.
4. Describe the various factors affecting activity of vasomotor
center.
Control of Heart & Vessels
ANS Innervation
Cardiac Peripheral
Sympathetic Vasoconstrictors
 Epicardial
Parasympathetic Vasodilators.
 Endocardial
Preganglionic
Postganglionic
1:Sympathetic N cells lie in the
intermediolateral horn of spinal
cord T1-T5 segments.
2:Myelinated preganglionic fibers
pass into the sympathetic trunk to
superior , middle & inferior cardiac
ganglia.
3:Synapse then unmylienated post-
ganglionic fibers pass via the
superior, middle & inferior cardiac
sympathetic fibers.
Supply: Nodal tissues: SAN,
AVN & muscles of atria &
ventricles. T1 –T5 segments
1
2
3
Brief
Sympathetic NS
Ionotropic
Chronotropic
Dromotropic
Bathmotropic
Target
NT substances
Vessels with
smooth muscles
Norepinephrine
ATP
Neuropeptide Y
γ 1NPYVC
Receptors
Purnergic
P2 ATP VC
Adrenergic
α1VC
α2VC/VD
β1 & β2VD
Vascular
Heart
+Ve
1. Cell bodies of Vagus nerves
lies in medulla oblongata in
Nucleus ambiguous
2. Myelinated preganglionic fibers
travel in vagi & synapse with
ganglionic cells located near the
SAN , AVN & in atria.
3. Unmylienated Postganglionic
fibers arise & are distributed to
SAN , AVN & atrial muscles.
Vagal tone
At rest : Vagal tone predominates
over sympathetic tone in heart .
1
2
3
Ventricles have NO Vagal Fibers
Peripheral vascular innervation
I:Vasoconstriction
By Sympathetic NS : Sympathetic tone
 Cell bodies from intermediate lateral horn cells of T1 – L2
spinal segments. Tonic effect on all vessels.
 Except: Cerebral vessels , true capillaries & coronary vessels
 Dense innervation :Arterioles, metarterioles ,pre-capillary
sphincters & post-capillary venules.
Actions :
1:Vasocontriction:Through β2 adrenergic receptors .
*On resistance vessels: Peripheral resistance  Regulate BP.
*Capacitance vessels(veins): Regulate blood Volume.
*Arterioles Vasoconstriction regulated VR & thus control BP.
2:Vasodilation: On skeletal muscles, erectile tissue of
reproductive system & facial blood vessels .
II:Vasodilation
1: Reduction of sympathetic constrictors tone.
2:Specific activation of vasodilators through
A:Sympathetic cholinergic Nn :Ex: Skeletal muscles, heart, lungs
liver, kidneys & uterus .Exercise /child birth increases blood flow.
B:Parasympathetic vasodilator nerves: Nervi erigentes
Ex: Nn : erectile tissue of reproductive system, salivary gland.
3:Dorsal root vasodilation : Axon reflex: Local neural
mechanisms: :
Brief
Parasympathetic
NS
Ionotropic
Chronotropic
Dromotropic
Bathmotropic
Target
NT substances
Arteries & Veins
Ach
Receptors
Muscuranic
M3VD
Few no.
Vascular
Heart
-Ve
Receptors
M2
Ventricles have NO Vagal Fibers
Lecture nerual regulation of circulation
Medullary control the heart
Cardiovascular center are group of neurons in CNS that regulate
HR, SV and vascular tone .
Medullary regulation of CVs is brought by two different centers
located in the medulla:
1: Medullary cv center: Vasomotor center / vasomotor area
• Pressor and Depressor areas
2:Cardiac vagal center
Regulated by signals from baroreceptors.
Lecture nerual regulation of circulation
Vasoconstrictor center/vasopressor area
Location: Bilaterally in the antrolateral portion of the upper medulla.
Neurons: Glutaminergic neurons excitatory effect on spinal
sympathetic neurons.
 Under normal conditions, transmits signals continuously to the
sympathetic vasoconstrictor nerve fibers over the entire body, 
slow firing of these fibers at a rate of about ½-2 impulses/ second.
 lead to sympathetic vasoconstrictor tone.
 Significance: Impulses normally maintain a partial state of
contraction in the blood vessels, called vasomotor tone.
Pressor effect on CVS
 Increase HR(Heart Rate)
 Increase BP (Blood pressure)
 Vasoconstriction leads to decrease blood stored in venous
reservoir and increase venous return (VR).
Depressor area
Location: Near medial & caudal parts of 4th ventricle in medulla.
Action:
Stimulation leads to decrease in sympathetic activity by
inhibiting the tonically discharging impulses of the Pressor area
neurons
Effect:
 Decrease HR,SV
 BP (due to vasodilation)
 Venodilatation increases storage of blood in venous
reservoirs & decrease VR.
Cardiovagal Centre
 Inhibitory pathways in the form of vagal fibers from the
medulla to converge on Sympathetic preganglionic neurons of
the spinal cord to decrease sympathetic activity.
On Heart: Decrease the HR & force of contraction.
Vagal fibers arise from 3 different nuclei located in the medulla.
A:Dorsal motor nucleus of the Vagus (Cardio-
inhibitory Centre).
B: Nucleus of tractus solitarius (NTS)
 Receives afferents from most of the baroreceptors & its fibers
are projected to the nucleus ambiguous & dorsal motor nucleus
of Vagus.
C: Nucleus ambiguous : lies lateral to the medullary
reticular neurons .
 Receives afferents via NTS and in turn sends impulses to the
heart.
 Also called as cardiac vagal center .
 Neurons are not tonically active.
Factors affecting the VMC
1: Neural factors:
A: Higher centers: Cerebral cortex, Hypothalamus ,Respiratory
center..
2:Afferent impulses: Circulatory system
Baroreceptors of Arterial & Atria & Chemoreceptors..
3: Other parts of the body: Cutaneous pain, Visceral pain
Proprioceptors, Loven’s reflex, Cold Pressor test.
2: Chemical factors :CO2.O2,H+ ions.
Nervous Regulation of HR
1:Impulses from higher centers:
Cerebral cortex :Motor cortex ,Ant temporal lobe, frontal cortex
,amygdala hippocampus act through hypothalamus.
Action:
Excitatory/ Inhibitory
Direct /indirect action the hypothalamus (emotions)
Conditioned reflex in to response to visual, smell, hearing stimuli
or even thoughts.
3:Respiratory center: HR ↑ with inspiration & ↓ with expiration .
Respiratory sinus arrhythmia".
Mechanism: i: Central mechanism: Active inspiratory center
activation causing stimulation of the CAC.
II: Peripheral mechanism: Lung inflation stimulates the stretch
receptors in the alveoli -> afferent impulses via the pulmonary vagi
--> -- CIC & ++ CAC.
* Harrison's reflex: During expiration, HR ↓ due to decreased
activity of inspiratory center, elastic recoil of the lungs and
decreased venous return.
2: Hypothalamus
Anterior hypothalamic nuclei :Control parasympathetic activities
-> ↓ HR stimulate CIC. During sleep & severe emotion.
Posterior hypothalamic nuclei: control sympathetic activities -> ↑
HR stimulate CAC.
Mild emotion, stress, muscular exercise or anxiety.
Voluntarily: ↑ /↓ HR : meditation/yoga.
Emotions : Mild : fear, anger, sexual excitation etc. -> ↑ HR.
Severe: Sudden shocking news -> ↓ HR.
Baroreceptors:
Mechanoreceptors/Stretch receptors
Sensitive to stretch of vessels by dynamic blood flow
Increased baroreceptors discharge inhibit tonic discharge of pressor
area of VMC & excite CVC.
Range of activation is 60 to 200 mmHg
60 mmHg is the threshold of baroreceptor reflex.
1:Arterial baroreceptors
Innervation: Vagus nerve
Except carotid sinus:
By carotid sinus N branch of IX N.
Afferents : To NTS secretes NT Glutamate.
Efferents: Excitatory glutaminigergic fibers terminates into VMC pressor
area thus stimulate GABA secreting inhibitory neurons
NA & Dorsal motor nucleus of vagus thus activate the neurons.
Buffer nerves : IX & X N branches  Sino aortic nerves regulate BP
2:Atrial receptors/Nonmylinated atrial afferents
Innervated by nonmylinated C fibers of X N.
Discharge is irregular & slow .Present all over atria & interseputm of atria
Function: atrial pressure impulses vasodilation mainly in renal
vascular circuit.
pO2 <50 mmHg ++Chemoreceptors impulses along IX a& X N
chemosenstive area of medullastimulating respiratory center
Ventilation drive &Parasympathetic --HR
Sensitive to chemical changes in blood :Co2 ,O2 and pH.
Carotid bodies: At bifurcation of CC A:N:Carotid sinus N IX N
Aortic bodies : around arch of aorta N: Aortic N of X N
Afferent: to NTS of medulla
Operate best 40 -100 mmHg. When stimulated they stimulate VMC
& respiratory neurons in medulla.
3:chemoreceptors
2:Afferent impulses from the body other than the CV system:
Stimulation of the central end of any nerve containing afferent
fibers e.g. radial, sciatic or splanchnic ↑ / ↓ HR according to
the nature of the stimulus.
a- Impulses from skeletal muscles (Alams Smirk reflex)
Contraction of voluntary muscles produces reflex tachycardia.
Mechanism: Muscle contraction --> + + Proprioceptors in the
muscle & joints
--> Afferent somatic sensory nerves --> + + CAC & - - CIC -->
Increase HR.
Significance: Helps to ↑ blood supply to the active muscle.
1) Cutaneous pain: Mild pain---> ++ VMC ,severe pain--> -- VMC
2) Severe visceral pain afferent fibers from the trigger zones -- VMC
Trigger zone reflexes : Carotid sinus, Eye balls, Larynx, Epigastrium &
Testes are sensitive.
A blow on these areas produces reflex severe bradycardia /fainting /
cardiac arrest/.
3) Afferent impulses from the Proprioceptors of skeletal muscles
during exercise ++ VMC.
Impulses from pain receptors:
4) Loven reflex:
Stimulation of the afferent nerve of an organ produces local
vasodilatation in the active organ.
But generalized vasoconstriction due to stimulation of the VMC.
Leads to HT & localized vasodilation and increased blood flow to
the organ.
5) Cold pressor test:
If a normal person drips his hand in a cold water (4oC), ABP rises by
10-20 mmHg, due to stimulation of the VMC.
McDowall reflex:
Decreased venous return, i.e., decreased right atrial pr as in
hemorrhage leads to reflex increase of HR & of vasoconstrictor tone
of arterioles and venules.
Significance:
This helps to maintain the normal ABP to allow sufficient
supply of blood flow to the vital organs like brain, heart, & kidneys.
Marey's law
HR is inversely proportional to the ABP provided that other factors
that affect the HR remain constant. i.e., ↑ ABP  ↓ HR Stimulus: ↑
ABP.
Receptors: Arterial baroreceptors. Carotid sinus & aortic arch.
Afferent: sinus nerve of IX & aortic nerve of X. Called "depressor
nerves" as they resist rise in ABP.
Center: + + CIC & - - CAC.
Efferent: X N.
Response: - - SAN  ↓ HR.
Significance:↓ ed HR antagonizes the elevation of ABP & helps to
restore it to its normal level.
Carotid sinus syndrome
Condition in which the carotid sinus is abnormally hypersensitive.
Manifestations:
A slight pressure on the carotid sinus (e.g. during shaving or by
tight collar) stimulates the baroreceptors in the carotid sinus 
reflex ↑ vagal tone to the heart & ↓ sympathetic vasoconstrictor
tone to the blood vessels  bradycardia (↓ HR) and hypotension
↓ ABP cerebral ischemia & momentarily loss of consciousness
(fainting).
Treatment:
Denervation of the hypersensitive carotid sinus cures the
condition.
Clinical significance:
Carotid sinus reflex could be used to terminate an attack
of paroxysmal atrial tachycardia (PAT) but not of ventricular
origin, as the vagus does not supply the ventricles.

More Related Content

What's hot

Regulation of Respiration
Regulation of RespirationRegulation of Respiration
Regulation of Respiration
Nabeel Beeran Abdul Rahiman
 
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...
Physiology Dept
 
Cardiac output
Cardiac outputCardiac output
Cardiac output
atsmp
 
Cardiovascular regulation
Cardiovascular regulationCardiovascular regulation
Cardiovascular regulation
Virinderpal Singh Chauhan
 
Heart Nerve Anatomy Cardiac Innervation
Heart Nerve Anatomy Cardiac InnervationHeart Nerve Anatomy Cardiac Innervation
Heart Nerve Anatomy Cardiac Innervation
Neeraj Mehta
 
Cardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipur
Cardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipurCardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipur
Cardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipur
manishdmcardio
 
Cardiac output (The Guyton and Hall Physiology)
Cardiac output (The Guyton and Hall Physiology)Cardiac output (The Guyton and Hall Physiology)
Cardiac output (The Guyton and Hall Physiology)
Maryam Fida
 
Local control of blood flow
Local control of blood flow Local control of blood flow
Local control of blood flow
mediciti institute of medical sciences
 
The neuromuscular physiology
The neuromuscular physiologyThe neuromuscular physiology
The neuromuscular physiology
Sourav Mondal
 
Neuron physiology
Neuron physiologyNeuron physiology
Neuron physiology
Yogesh Ramasamy
 
Regulation of arterial blood pressure
Regulation of arterial blood pressureRegulation of arterial blood pressure
Regulation of arterial blood pressure
kamla13
 
Coronary circulation
Coronary circulationCoronary circulation
Coronary circulation
Tehmina Naru
 
the cardiovascular system and Physiology of heart
the cardiovascular system and Physiology of heartthe cardiovascular system and Physiology of heart
the cardiovascular system and Physiology of heart
bhupendra kumar
 
7. Development of veins.
7. Development of veins.7. Development of veins.
7. Development of veins.
Dr. Mohammad Mahmoud
 
Embryology cardiovascular system (heart development)
Embryology   cardiovascular system (heart development)Embryology   cardiovascular system (heart development)
Embryology cardiovascular system (heart development)
MBBS IMS MSU
 
Physiology of the Neuromuscular Junction
Physiology of the Neuromuscular JunctionPhysiology of the Neuromuscular Junction
Physiology of the Neuromuscular Junction
Ashwin Haridas
 
Microcirculation
Microcirculation Microcirculation
Microcirculation
rashidrmc
 
Cardiac cycle physiology_4_dpt
Cardiac cycle physiology_4_dptCardiac cycle physiology_4_dpt
Cardiac cycle physiology_4_dpt
Student
 
The coronary circulation
The coronary circulationThe coronary circulation
The coronary circulation
Idris Siddiqui
 
Cvs7
Cvs7Cvs7

What's hot (20)

Regulation of Respiration
Regulation of RespirationRegulation of Respiration
Regulation of Respiration
 
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...
 
Cardiac output
Cardiac outputCardiac output
Cardiac output
 
Cardiovascular regulation
Cardiovascular regulationCardiovascular regulation
Cardiovascular regulation
 
Heart Nerve Anatomy Cardiac Innervation
Heart Nerve Anatomy Cardiac InnervationHeart Nerve Anatomy Cardiac Innervation
Heart Nerve Anatomy Cardiac Innervation
 
Cardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipur
Cardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipurCardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipur
Cardiac innervation seminar by Dr Manish Ruhela, SMS Medical College,jaipur
 
Cardiac output (The Guyton and Hall Physiology)
Cardiac output (The Guyton and Hall Physiology)Cardiac output (The Guyton and Hall Physiology)
Cardiac output (The Guyton and Hall Physiology)
 
Local control of blood flow
Local control of blood flow Local control of blood flow
Local control of blood flow
 
The neuromuscular physiology
The neuromuscular physiologyThe neuromuscular physiology
The neuromuscular physiology
 
Neuron physiology
Neuron physiologyNeuron physiology
Neuron physiology
 
Regulation of arterial blood pressure
Regulation of arterial blood pressureRegulation of arterial blood pressure
Regulation of arterial blood pressure
 
Coronary circulation
Coronary circulationCoronary circulation
Coronary circulation
 
the cardiovascular system and Physiology of heart
the cardiovascular system and Physiology of heartthe cardiovascular system and Physiology of heart
the cardiovascular system and Physiology of heart
 
7. Development of veins.
7. Development of veins.7. Development of veins.
7. Development of veins.
 
Embryology cardiovascular system (heart development)
Embryology   cardiovascular system (heart development)Embryology   cardiovascular system (heart development)
Embryology cardiovascular system (heart development)
 
Physiology of the Neuromuscular Junction
Physiology of the Neuromuscular JunctionPhysiology of the Neuromuscular Junction
Physiology of the Neuromuscular Junction
 
Microcirculation
Microcirculation Microcirculation
Microcirculation
 
Cardiac cycle physiology_4_dpt
Cardiac cycle physiology_4_dptCardiac cycle physiology_4_dpt
Cardiac cycle physiology_4_dpt
 
The coronary circulation
The coronary circulationThe coronary circulation
The coronary circulation
 
Cvs7
Cvs7Cvs7
Cvs7
 

Similar to Lecture nerual regulation of circulation

Cvs7
Cvs7Cvs7
Blood pressure mechanism
Blood pressure mechanismBlood pressure mechanism
Blood pressure mechanism
Jaineel Dharod
 
HEART RATE_030325.pptx
HEART RATE_030325.pptxHEART RATE_030325.pptx
HEART RATE_030325.pptx
OutaRobert1
 
Heart rate by pandian m
Heart rate by pandian mHeart rate by pandian m
Heart rate by pandian m
Physiology Dept
 
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...
Pandian M
 
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MHHeart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH
Pandian M
 
Autonomic nervous system
Autonomic nervous systemAutonomic nervous system
Autonomic nervous system
dina merzeban
 
Regulation of blood pressure.pdf
Regulation of blood pressure.pdfRegulation of blood pressure.pdf
Regulation of blood pressure.pdf
SakshiVishwakarma15
 
Blood pressure mechanism
Blood pressure mechanismBlood pressure mechanism
Blood pressure mechanism
MBBS IMS MSU
 
Chapter15 autonomicns marieb
Chapter15 autonomicns mariebChapter15 autonomicns marieb
Chapter15 autonomicns marieb
Martin Klüssendorf
 
Blood
BloodBlood
Ans(organization , subdivision and innervations)
Ans(organization , subdivision and innervations)Ans(organization , subdivision and innervations)
Ans(organization , subdivision and innervations)
Zulcaif Ahmad
 
Lecture 5 ans
Lecture 5   ansLecture 5   ans
Lecture 5 ans
missazyaziz
 
Control of heart rate
Control of heart rateControl of heart rate
Control of heart rate
Traceywithane
 
nursing lecture.pptx
nursing lecture.pptxnursing lecture.pptx
nursing lecture.pptx
muhammedrisham3
 
A-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptx
A-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptxA-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptx
A-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptx
imranmushtaq22
 
Autonomic Nervous System.pptx
Autonomic Nervous System.pptxAutonomic Nervous System.pptx
Autonomic Nervous System.pptx
KALYANI SAUDAGAR
 
L9 Cardiac Cycle
L9 Cardiac CycleL9 Cardiac Cycle
L9 Cardiac Cycle
Marc Potter
 
CARDIAC AUTONOMIC SYSTEM CLINICAL SIGNIFICANCE.pptx
CARDIAC AUTONOMIC SYSTEM  CLINICAL SIGNIFICANCE.pptxCARDIAC AUTONOMIC SYSTEM  CLINICAL SIGNIFICANCE.pptx
CARDIAC AUTONOMIC SYSTEM CLINICAL SIGNIFICANCE.pptx
aamirrashid39
 
A heart physiology
A heart physiologyA heart physiology
A heart physiology
levouge777
 

Similar to Lecture nerual regulation of circulation (20)

Cvs7
Cvs7Cvs7
Cvs7
 
Blood pressure mechanism
Blood pressure mechanismBlood pressure mechanism
Blood pressure mechanism
 
HEART RATE_030325.pptx
HEART RATE_030325.pptxHEART RATE_030325.pptx
HEART RATE_030325.pptx
 
Heart rate by pandian m
Heart rate by pandian mHeart rate by pandian m
Heart rate by pandian m
 
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH. This ppt for...
 
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MHHeart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH
Heart rate by Pandian M, Tutor, Dept of Physiology, DYPMCKOP,MH
 
Autonomic nervous system
Autonomic nervous systemAutonomic nervous system
Autonomic nervous system
 
Regulation of blood pressure.pdf
Regulation of blood pressure.pdfRegulation of blood pressure.pdf
Regulation of blood pressure.pdf
 
Blood pressure mechanism
Blood pressure mechanismBlood pressure mechanism
Blood pressure mechanism
 
Chapter15 autonomicns marieb
Chapter15 autonomicns mariebChapter15 autonomicns marieb
Chapter15 autonomicns marieb
 
Blood
BloodBlood
Blood
 
Ans(organization , subdivision and innervations)
Ans(organization , subdivision and innervations)Ans(organization , subdivision and innervations)
Ans(organization , subdivision and innervations)
 
Lecture 5 ans
Lecture 5   ansLecture 5   ans
Lecture 5 ans
 
Control of heart rate
Control of heart rateControl of heart rate
Control of heart rate
 
nursing lecture.pptx
nursing lecture.pptxnursing lecture.pptx
nursing lecture.pptx
 
A-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptx
A-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptxA-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptx
A-Level-Biology-Lecture-The-Control-of-Heart-Rate.pptx
 
Autonomic Nervous System.pptx
Autonomic Nervous System.pptxAutonomic Nervous System.pptx
Autonomic Nervous System.pptx
 
L9 Cardiac Cycle
L9 Cardiac CycleL9 Cardiac Cycle
L9 Cardiac Cycle
 
CARDIAC AUTONOMIC SYSTEM CLINICAL SIGNIFICANCE.pptx
CARDIAC AUTONOMIC SYSTEM  CLINICAL SIGNIFICANCE.pptxCARDIAC AUTONOMIC SYSTEM  CLINICAL SIGNIFICANCE.pptx
CARDIAC AUTONOMIC SYSTEM CLINICAL SIGNIFICANCE.pptx
 
A heart physiology
A heart physiologyA heart physiology
A heart physiology
 

More from Dr Shamshad Begum loni

new taboacco smoking for red cresecent for slide share .ppsx
new taboacco smoking  for red cresecent for slide share .ppsxnew taboacco smoking  for red cresecent for slide share .ppsx
new taboacco smoking for red cresecent for slide share .ppsx
Dr Shamshad Begum loni
 
Examination of all Cranial Nerves Examination jan 2023 updated pdf .pdf
Examination of all Cranial Nerves Examination   jan 2023 updated pdf .pdfExamination of all Cranial Nerves Examination   jan 2023 updated pdf .pdf
Examination of all Cranial Nerves Examination jan 2023 updated pdf .pdf
Dr Shamshad Begum loni
 
L 32 Pathophysiology of End-Stage Renal Disease 2023.pptx
L 32 Pathophysiology of End-Stage Renal Disease  2023.pptxL 32 Pathophysiology of End-Stage Renal Disease  2023.pptx
L 32 Pathophysiology of End-Stage Renal Disease 2023.pptx
Dr Shamshad Begum loni
 
Check list for students vital signs created on 27 august 2022.pdf
Check list for students vital signs created on 27 august 2022.pdfCheck list for students vital signs created on 27 august 2022.pdf
Check list for students vital signs created on 27 august 2022.pdf
Dr Shamshad Begum loni
 
CSK vital sign 2022.pdf
CSK vital sign 2022.pdfCSK vital sign 2022.pdf
CSK vital sign 2022.pdf
Dr Shamshad Begum loni
 
L 54 Endocrine system 2022.pdf
L 54 Endocrine system   2022.pdfL 54 Endocrine system   2022.pdf
L 54 Endocrine system 2022.pdf
Dr Shamshad Begum loni
 
breast examination for students slide share.pdf
breast examination for students slide share.pdfbreast examination for students slide share.pdf
breast examination for students slide share.pdf
Dr Shamshad Begum loni
 
ultimate to upload updated on 14september 2022 Thyroid examination.pptx
ultimate to upload updated on 14september 2022 Thyroid examination.pptxultimate to upload updated on 14september 2022 Thyroid examination.pptx
ultimate to upload updated on 14september 2022 Thyroid examination.pptx
Dr Shamshad Begum loni
 
check list for thyroid gland examination.docx
check list for thyroid gland examination.docxcheck list for thyroid gland examination.docx
check list for thyroid gland examination.docx
Dr Shamshad Begum loni
 
latest prostrate examination 2022 with check list.pptx
latest prostrate examination 2022 with check list.pptxlatest prostrate examination 2022 with check list.pptx
latest prostrate examination 2022 with check list.pptx
Dr Shamshad Begum loni
 
history taking Clinical assessment of endocrine system 2022.pdf
history taking  Clinical assessment of endocrine system 2022.pdfhistory taking  Clinical assessment of endocrine system 2022.pdf
history taking Clinical assessment of endocrine system 2022.pdf
Dr Shamshad Begum loni
 
Endocrine functions of the Testsis 2022.pdf
Endocrine functions of the Testsis 2022.pdfEndocrine functions of the Testsis 2022.pdf
Endocrine functions of the Testsis 2022.pdf
Dr Shamshad Begum loni
 
Lecture 7: Fluid loss and management
Lecture 7: Fluid loss and management Lecture 7: Fluid loss and management
Lecture 7: Fluid loss and management
Dr Shamshad Begum loni
 
Blood group and typing 2021
Blood group and typing 2021Blood group and typing 2021
Blood group and typing 2021
Dr Shamshad Begum loni
 
Visual transduction ppt 2021
Visual transduction ppt 2021 Visual transduction ppt 2021
Visual transduction ppt 2021
Dr Shamshad Begum loni
 
Updated 2021 lecture 45
Updated 2021 lecture 45  Updated 2021 lecture 45
Updated 2021 lecture 45
Dr Shamshad Begum loni
 
Updated lecture 58
Updated lecture 58 Updated lecture 58
Updated lecture 58
Dr Shamshad Begum loni
 
Lect 13
Lect 13 Lect 13
Practical 8 reflexes
Practical 8 reflexesPractical 8 reflexes
Practical 8 reflexes
Dr Shamshad Begum loni
 
lecture 45 Endocrine functions of the testis 2021
lecture 45  Endocrine functions of the testis 2021lecture 45  Endocrine functions of the testis 2021
lecture 45 Endocrine functions of the testis 2021
Dr Shamshad Begum loni
 

More from Dr Shamshad Begum loni (20)

new taboacco smoking for red cresecent for slide share .ppsx
new taboacco smoking  for red cresecent for slide share .ppsxnew taboacco smoking  for red cresecent for slide share .ppsx
new taboacco smoking for red cresecent for slide share .ppsx
 
Examination of all Cranial Nerves Examination jan 2023 updated pdf .pdf
Examination of all Cranial Nerves Examination   jan 2023 updated pdf .pdfExamination of all Cranial Nerves Examination   jan 2023 updated pdf .pdf
Examination of all Cranial Nerves Examination jan 2023 updated pdf .pdf
 
L 32 Pathophysiology of End-Stage Renal Disease 2023.pptx
L 32 Pathophysiology of End-Stage Renal Disease  2023.pptxL 32 Pathophysiology of End-Stage Renal Disease  2023.pptx
L 32 Pathophysiology of End-Stage Renal Disease 2023.pptx
 
Check list for students vital signs created on 27 august 2022.pdf
Check list for students vital signs created on 27 august 2022.pdfCheck list for students vital signs created on 27 august 2022.pdf
Check list for students vital signs created on 27 august 2022.pdf
 
CSK vital sign 2022.pdf
CSK vital sign 2022.pdfCSK vital sign 2022.pdf
CSK vital sign 2022.pdf
 
L 54 Endocrine system 2022.pdf
L 54 Endocrine system   2022.pdfL 54 Endocrine system   2022.pdf
L 54 Endocrine system 2022.pdf
 
breast examination for students slide share.pdf
breast examination for students slide share.pdfbreast examination for students slide share.pdf
breast examination for students slide share.pdf
 
ultimate to upload updated on 14september 2022 Thyroid examination.pptx
ultimate to upload updated on 14september 2022 Thyroid examination.pptxultimate to upload updated on 14september 2022 Thyroid examination.pptx
ultimate to upload updated on 14september 2022 Thyroid examination.pptx
 
check list for thyroid gland examination.docx
check list for thyroid gland examination.docxcheck list for thyroid gland examination.docx
check list for thyroid gland examination.docx
 
latest prostrate examination 2022 with check list.pptx
latest prostrate examination 2022 with check list.pptxlatest prostrate examination 2022 with check list.pptx
latest prostrate examination 2022 with check list.pptx
 
history taking Clinical assessment of endocrine system 2022.pdf
history taking  Clinical assessment of endocrine system 2022.pdfhistory taking  Clinical assessment of endocrine system 2022.pdf
history taking Clinical assessment of endocrine system 2022.pdf
 
Endocrine functions of the Testsis 2022.pdf
Endocrine functions of the Testsis 2022.pdfEndocrine functions of the Testsis 2022.pdf
Endocrine functions of the Testsis 2022.pdf
 
Lecture 7: Fluid loss and management
Lecture 7: Fluid loss and management Lecture 7: Fluid loss and management
Lecture 7: Fluid loss and management
 
Blood group and typing 2021
Blood group and typing 2021Blood group and typing 2021
Blood group and typing 2021
 
Visual transduction ppt 2021
Visual transduction ppt 2021 Visual transduction ppt 2021
Visual transduction ppt 2021
 
Updated 2021 lecture 45
Updated 2021 lecture 45  Updated 2021 lecture 45
Updated 2021 lecture 45
 
Updated lecture 58
Updated lecture 58 Updated lecture 58
Updated lecture 58
 
Lect 13
Lect 13 Lect 13
Lect 13
 
Practical 8 reflexes
Practical 8 reflexesPractical 8 reflexes
Practical 8 reflexes
 
lecture 45 Endocrine functions of the testis 2021
lecture 45  Endocrine functions of the testis 2021lecture 45  Endocrine functions of the testis 2021
lecture 45 Endocrine functions of the testis 2021
 

Recently uploaded

RDBMS Lecture Notes Unit4 chapter12 VIEW
RDBMS Lecture Notes Unit4 chapter12 VIEWRDBMS Lecture Notes Unit4 chapter12 VIEW
RDBMS Lecture Notes Unit4 chapter12 VIEW
Murugan Solaiyappan
 
CTD Punjab Police Past Papers MCQs PPSC PDF
CTD Punjab Police Past Papers MCQs PPSC PDFCTD Punjab Police Past Papers MCQs PPSC PDF
CTD Punjab Police Past Papers MCQs PPSC PDF
hammadmughal76316
 
How to Create & Publish a Blog in Odoo 17 Website
How to Create & Publish a Blog in Odoo 17 WebsiteHow to Create & Publish a Blog in Odoo 17 Website
How to Create & Publish a Blog in Odoo 17 Website
Celine George
 
Mail Server Configuration Using App passwords in Odoo 17
Mail Server Configuration Using App passwords in Odoo 17Mail Server Configuration Using App passwords in Odoo 17
Mail Server Configuration Using App passwords in Odoo 17
Celine George
 
SEQUNCES Lecture_Notes_Unit4_chapter11_sequence
SEQUNCES  Lecture_Notes_Unit4_chapter11_sequenceSEQUNCES  Lecture_Notes_Unit4_chapter11_sequence
SEQUNCES Lecture_Notes_Unit4_chapter11_sequence
Murugan Solaiyappan
 
modul ajar kelas x bahasa inggris 24/254
modul ajar kelas x bahasa inggris 24/254modul ajar kelas x bahasa inggris 24/254
modul ajar kelas x bahasa inggris 24/254
NurFitriah45
 
ASP.NET Core Interview Questions PDF By ScholarHat.pdf
ASP.NET Core Interview Questions PDF By ScholarHat.pdfASP.NET Core Interview Questions PDF By ScholarHat.pdf
ASP.NET Core Interview Questions PDF By ScholarHat.pdf
Scholarhat
 
"DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ...
"DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ..."DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ...
"DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ...
thanhluan21
 
Kesadaran_Berbangsa_dan_Bernegara_Nasion.pptx
Kesadaran_Berbangsa_dan_Bernegara_Nasion.pptxKesadaran_Berbangsa_dan_Bernegara_Nasion.pptx
Kesadaran_Berbangsa_dan_Bernegara_Nasion.pptx
artenzmartenkai
 
DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...
DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...
DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...
thanhluan21
 
Allopathic M1 Srudent Orientation Powerpoint
Allopathic M1 Srudent Orientation PowerpointAllopathic M1 Srudent Orientation Powerpoint
Allopathic M1 Srudent Orientation Powerpoint
Julie Sarpy
 
How To Create a Transient Model in Odoo 17
How To Create a Transient Model in Odoo 17How To Create a Transient Model in Odoo 17
How To Create a Transient Model in Odoo 17
Celine George
 
E-learning Odoo 17 New features - Odoo 17 Slides
E-learning Odoo 17  New features - Odoo 17 SlidesE-learning Odoo 17  New features - Odoo 17 Slides
E-learning Odoo 17 New features - Odoo 17 Slides
Celine George
 
Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...
Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...
Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...
Alvaro Barbosa
 
matatag curriculum education for Kindergarten
matatag curriculum education for Kindergartenmatatag curriculum education for Kindergarten
matatag curriculum education for Kindergarten
SarahAlie1
 
View Inheritance in Odoo 17 - Odoo 17 Slides
View Inheritance in Odoo 17 - Odoo 17  SlidesView Inheritance in Odoo 17 - Odoo 17  Slides
View Inheritance in Odoo 17 - Odoo 17 Slides
Celine George
 
Odoo 17 Events - Attendees List Scanning
Odoo 17 Events - Attendees List ScanningOdoo 17 Events - Attendees List Scanning
Odoo 17 Events - Attendees List Scanning
Celine George
 
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...
Nguyen Thanh Tu Collection
 
How to Manage Access Rights & User Types in Odoo 17
How to Manage Access Rights & User Types in Odoo 17How to Manage Access Rights & User Types in Odoo 17
How to Manage Access Rights & User Types in Odoo 17
Celine George
 
Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)
Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)
Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)
Cátedra Banco Santander
 

Recently uploaded (20)

RDBMS Lecture Notes Unit4 chapter12 VIEW
RDBMS Lecture Notes Unit4 chapter12 VIEWRDBMS Lecture Notes Unit4 chapter12 VIEW
RDBMS Lecture Notes Unit4 chapter12 VIEW
 
CTD Punjab Police Past Papers MCQs PPSC PDF
CTD Punjab Police Past Papers MCQs PPSC PDFCTD Punjab Police Past Papers MCQs PPSC PDF
CTD Punjab Police Past Papers MCQs PPSC PDF
 
How to Create & Publish a Blog in Odoo 17 Website
How to Create & Publish a Blog in Odoo 17 WebsiteHow to Create & Publish a Blog in Odoo 17 Website
How to Create & Publish a Blog in Odoo 17 Website
 
Mail Server Configuration Using App passwords in Odoo 17
Mail Server Configuration Using App passwords in Odoo 17Mail Server Configuration Using App passwords in Odoo 17
Mail Server Configuration Using App passwords in Odoo 17
 
SEQUNCES Lecture_Notes_Unit4_chapter11_sequence
SEQUNCES  Lecture_Notes_Unit4_chapter11_sequenceSEQUNCES  Lecture_Notes_Unit4_chapter11_sequence
SEQUNCES Lecture_Notes_Unit4_chapter11_sequence
 
modul ajar kelas x bahasa inggris 24/254
modul ajar kelas x bahasa inggris 24/254modul ajar kelas x bahasa inggris 24/254
modul ajar kelas x bahasa inggris 24/254
 
ASP.NET Core Interview Questions PDF By ScholarHat.pdf
ASP.NET Core Interview Questions PDF By ScholarHat.pdfASP.NET Core Interview Questions PDF By ScholarHat.pdf
ASP.NET Core Interview Questions PDF By ScholarHat.pdf
 
"DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ...
"DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ..."DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ...
"DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY ...
 
Kesadaran_Berbangsa_dan_Bernegara_Nasion.pptx
Kesadaran_Berbangsa_dan_Bernegara_Nasion.pptxKesadaran_Berbangsa_dan_Bernegara_Nasion.pptx
Kesadaran_Berbangsa_dan_Bernegara_Nasion.pptx
 
DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...
DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...
DANH SÁCH THÍ SINH XÉT TUYỂN SỚM ĐỦ ĐIỀU KIỆN TRÚNG TUYỂN ĐẠI HỌC CHÍNH QUY N...
 
Allopathic M1 Srudent Orientation Powerpoint
Allopathic M1 Srudent Orientation PowerpointAllopathic M1 Srudent Orientation Powerpoint
Allopathic M1 Srudent Orientation Powerpoint
 
How To Create a Transient Model in Odoo 17
How To Create a Transient Model in Odoo 17How To Create a Transient Model in Odoo 17
How To Create a Transient Model in Odoo 17
 
E-learning Odoo 17 New features - Odoo 17 Slides
E-learning Odoo 17  New features - Odoo 17 SlidesE-learning Odoo 17  New features - Odoo 17 Slides
E-learning Odoo 17 New features - Odoo 17 Slides
 
Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...
Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...
Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...
 
matatag curriculum education for Kindergarten
matatag curriculum education for Kindergartenmatatag curriculum education for Kindergarten
matatag curriculum education for Kindergarten
 
View Inheritance in Odoo 17 - Odoo 17 Slides
View Inheritance in Odoo 17 - Odoo 17  SlidesView Inheritance in Odoo 17 - Odoo 17  Slides
View Inheritance in Odoo 17 - Odoo 17 Slides
 
Odoo 17 Events - Attendees List Scanning
Odoo 17 Events - Attendees List ScanningOdoo 17 Events - Attendees List Scanning
Odoo 17 Events - Attendees List Scanning
 
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH LỚP 12 - GLOBAL SUCCESS - FORM MỚI 2025 - ...
 
How to Manage Access Rights & User Types in Odoo 17
How to Manage Access Rights & User Types in Odoo 17How to Manage Access Rights & User Types in Odoo 17
How to Manage Access Rights & User Types in Odoo 17
 
Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)
Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)
Cómo crear video-tutoriales con ScreenPal (2 de julio de 2024)
 

Lecture nerual regulation of circulation

  • 1. Nervous Regulation of Circulation Dr Shamshad Majamaah University Lecture 48
  • 2. Objectives: 1. Describe the physiological anatomy of autonomic supply to the heart & blood vessels. 2. Discuss the nervous control of circulatory functions esp. heart rate. 3. Describe the role of vasomotor center in regulation of circulatory functions. 4. Describe the various factors affecting activity of vasomotor center.
  • 3. Control of Heart & Vessels ANS Innervation Cardiac Peripheral Sympathetic Vasoconstrictors  Epicardial Parasympathetic Vasodilators.  Endocardial Preganglionic Postganglionic
  • 4. 1:Sympathetic N cells lie in the intermediolateral horn of spinal cord T1-T5 segments. 2:Myelinated preganglionic fibers pass into the sympathetic trunk to superior , middle & inferior cardiac ganglia. 3:Synapse then unmylienated post- ganglionic fibers pass via the superior, middle & inferior cardiac sympathetic fibers. Supply: Nodal tissues: SAN, AVN & muscles of atria & ventricles. T1 –T5 segments 1 2 3
  • 5. Brief Sympathetic NS Ionotropic Chronotropic Dromotropic Bathmotropic Target NT substances Vessels with smooth muscles Norepinephrine ATP Neuropeptide Y γ 1NPYVC Receptors Purnergic P2 ATP VC Adrenergic α1VC α2VC/VD β1 & β2VD Vascular Heart +Ve
  • 6. 1. Cell bodies of Vagus nerves lies in medulla oblongata in Nucleus ambiguous 2. Myelinated preganglionic fibers travel in vagi & synapse with ganglionic cells located near the SAN , AVN & in atria. 3. Unmylienated Postganglionic fibers arise & are distributed to SAN , AVN & atrial muscles. Vagal tone At rest : Vagal tone predominates over sympathetic tone in heart . 1 2 3 Ventricles have NO Vagal Fibers
  • 7. Peripheral vascular innervation I:Vasoconstriction By Sympathetic NS : Sympathetic tone  Cell bodies from intermediate lateral horn cells of T1 – L2 spinal segments. Tonic effect on all vessels.  Except: Cerebral vessels , true capillaries & coronary vessels  Dense innervation :Arterioles, metarterioles ,pre-capillary sphincters & post-capillary venules.
  • 8. Actions : 1:Vasocontriction:Through β2 adrenergic receptors . *On resistance vessels: Peripheral resistance  Regulate BP. *Capacitance vessels(veins): Regulate blood Volume. *Arterioles Vasoconstriction regulated VR & thus control BP. 2:Vasodilation: On skeletal muscles, erectile tissue of reproductive system & facial blood vessels .
  • 9. II:Vasodilation 1: Reduction of sympathetic constrictors tone. 2:Specific activation of vasodilators through A:Sympathetic cholinergic Nn :Ex: Skeletal muscles, heart, lungs liver, kidneys & uterus .Exercise /child birth increases blood flow. B:Parasympathetic vasodilator nerves: Nervi erigentes Ex: Nn : erectile tissue of reproductive system, salivary gland. 3:Dorsal root vasodilation : Axon reflex: Local neural mechanisms: :
  • 10. Brief Parasympathetic NS Ionotropic Chronotropic Dromotropic Bathmotropic Target NT substances Arteries & Veins Ach Receptors Muscuranic M3VD Few no. Vascular Heart -Ve Receptors M2 Ventricles have NO Vagal Fibers
  • 12. Medullary control the heart Cardiovascular center are group of neurons in CNS that regulate HR, SV and vascular tone . Medullary regulation of CVs is brought by two different centers located in the medulla: 1: Medullary cv center: Vasomotor center / vasomotor area • Pressor and Depressor areas 2:Cardiac vagal center Regulated by signals from baroreceptors.
  • 14. Vasoconstrictor center/vasopressor area Location: Bilaterally in the antrolateral portion of the upper medulla. Neurons: Glutaminergic neurons excitatory effect on spinal sympathetic neurons.  Under normal conditions, transmits signals continuously to the sympathetic vasoconstrictor nerve fibers over the entire body,  slow firing of these fibers at a rate of about ½-2 impulses/ second.  lead to sympathetic vasoconstrictor tone.  Significance: Impulses normally maintain a partial state of contraction in the blood vessels, called vasomotor tone.
  • 15. Pressor effect on CVS  Increase HR(Heart Rate)  Increase BP (Blood pressure)  Vasoconstriction leads to decrease blood stored in venous reservoir and increase venous return (VR).
  • 16. Depressor area Location: Near medial & caudal parts of 4th ventricle in medulla. Action: Stimulation leads to decrease in sympathetic activity by inhibiting the tonically discharging impulses of the Pressor area neurons Effect:  Decrease HR,SV  BP (due to vasodilation)  Venodilatation increases storage of blood in venous reservoirs & decrease VR.
  • 17. Cardiovagal Centre  Inhibitory pathways in the form of vagal fibers from the medulla to converge on Sympathetic preganglionic neurons of the spinal cord to decrease sympathetic activity. On Heart: Decrease the HR & force of contraction.
  • 18. Vagal fibers arise from 3 different nuclei located in the medulla. A:Dorsal motor nucleus of the Vagus (Cardio- inhibitory Centre). B: Nucleus of tractus solitarius (NTS)  Receives afferents from most of the baroreceptors & its fibers are projected to the nucleus ambiguous & dorsal motor nucleus of Vagus. C: Nucleus ambiguous : lies lateral to the medullary reticular neurons .  Receives afferents via NTS and in turn sends impulses to the heart.  Also called as cardiac vagal center .  Neurons are not tonically active.
  • 19. Factors affecting the VMC 1: Neural factors: A: Higher centers: Cerebral cortex, Hypothalamus ,Respiratory center.. 2:Afferent impulses: Circulatory system Baroreceptors of Arterial & Atria & Chemoreceptors.. 3: Other parts of the body: Cutaneous pain, Visceral pain Proprioceptors, Loven’s reflex, Cold Pressor test. 2: Chemical factors :CO2.O2,H+ ions.
  • 20. Nervous Regulation of HR 1:Impulses from higher centers: Cerebral cortex :Motor cortex ,Ant temporal lobe, frontal cortex ,amygdala hippocampus act through hypothalamus. Action: Excitatory/ Inhibitory Direct /indirect action the hypothalamus (emotions) Conditioned reflex in to response to visual, smell, hearing stimuli or even thoughts.
  • 21. 3:Respiratory center: HR ↑ with inspiration & ↓ with expiration . Respiratory sinus arrhythmia". Mechanism: i: Central mechanism: Active inspiratory center activation causing stimulation of the CAC. II: Peripheral mechanism: Lung inflation stimulates the stretch receptors in the alveoli -> afferent impulses via the pulmonary vagi --> -- CIC & ++ CAC. * Harrison's reflex: During expiration, HR ↓ due to decreased activity of inspiratory center, elastic recoil of the lungs and decreased venous return.
  • 22. 2: Hypothalamus Anterior hypothalamic nuclei :Control parasympathetic activities -> ↓ HR stimulate CIC. During sleep & severe emotion. Posterior hypothalamic nuclei: control sympathetic activities -> ↑ HR stimulate CAC. Mild emotion, stress, muscular exercise or anxiety. Voluntarily: ↑ /↓ HR : meditation/yoga. Emotions : Mild : fear, anger, sexual excitation etc. -> ↑ HR. Severe: Sudden shocking news -> ↓ HR.
  • 23. Baroreceptors: Mechanoreceptors/Stretch receptors Sensitive to stretch of vessels by dynamic blood flow Increased baroreceptors discharge inhibit tonic discharge of pressor area of VMC & excite CVC. Range of activation is 60 to 200 mmHg 60 mmHg is the threshold of baroreceptor reflex. 1:Arterial baroreceptors Innervation: Vagus nerve Except carotid sinus: By carotid sinus N branch of IX N.
  • 24. Afferents : To NTS secretes NT Glutamate. Efferents: Excitatory glutaminigergic fibers terminates into VMC pressor area thus stimulate GABA secreting inhibitory neurons NA & Dorsal motor nucleus of vagus thus activate the neurons. Buffer nerves : IX & X N branches  Sino aortic nerves regulate BP 2:Atrial receptors/Nonmylinated atrial afferents Innervated by nonmylinated C fibers of X N. Discharge is irregular & slow .Present all over atria & interseputm of atria Function: atrial pressure impulses vasodilation mainly in renal vascular circuit.
  • 25. pO2 <50 mmHg ++Chemoreceptors impulses along IX a& X N chemosenstive area of medullastimulating respiratory center Ventilation drive &Parasympathetic --HR Sensitive to chemical changes in blood :Co2 ,O2 and pH. Carotid bodies: At bifurcation of CC A:N:Carotid sinus N IX N Aortic bodies : around arch of aorta N: Aortic N of X N Afferent: to NTS of medulla Operate best 40 -100 mmHg. When stimulated they stimulate VMC & respiratory neurons in medulla. 3:chemoreceptors
  • 26. 2:Afferent impulses from the body other than the CV system: Stimulation of the central end of any nerve containing afferent fibers e.g. radial, sciatic or splanchnic ↑ / ↓ HR according to the nature of the stimulus. a- Impulses from skeletal muscles (Alams Smirk reflex) Contraction of voluntary muscles produces reflex tachycardia. Mechanism: Muscle contraction --> + + Proprioceptors in the muscle & joints --> Afferent somatic sensory nerves --> + + CAC & - - CIC --> Increase HR. Significance: Helps to ↑ blood supply to the active muscle.
  • 27. 1) Cutaneous pain: Mild pain---> ++ VMC ,severe pain--> -- VMC 2) Severe visceral pain afferent fibers from the trigger zones -- VMC Trigger zone reflexes : Carotid sinus, Eye balls, Larynx, Epigastrium & Testes are sensitive. A blow on these areas produces reflex severe bradycardia /fainting / cardiac arrest/. 3) Afferent impulses from the Proprioceptors of skeletal muscles during exercise ++ VMC. Impulses from pain receptors:
  • 28. 4) Loven reflex: Stimulation of the afferent nerve of an organ produces local vasodilatation in the active organ. But generalized vasoconstriction due to stimulation of the VMC. Leads to HT & localized vasodilation and increased blood flow to the organ. 5) Cold pressor test: If a normal person drips his hand in a cold water (4oC), ABP rises by 10-20 mmHg, due to stimulation of the VMC.
  • 29. McDowall reflex: Decreased venous return, i.e., decreased right atrial pr as in hemorrhage leads to reflex increase of HR & of vasoconstrictor tone of arterioles and venules. Significance: This helps to maintain the normal ABP to allow sufficient supply of blood flow to the vital organs like brain, heart, & kidneys.
  • 30. Marey's law HR is inversely proportional to the ABP provided that other factors that affect the HR remain constant. i.e., ↑ ABP  ↓ HR Stimulus: ↑ ABP. Receptors: Arterial baroreceptors. Carotid sinus & aortic arch. Afferent: sinus nerve of IX & aortic nerve of X. Called "depressor nerves" as they resist rise in ABP. Center: + + CIC & - - CAC. Efferent: X N. Response: - - SAN  ↓ HR. Significance:↓ ed HR antagonizes the elevation of ABP & helps to restore it to its normal level.
  • 31. Carotid sinus syndrome Condition in which the carotid sinus is abnormally hypersensitive. Manifestations: A slight pressure on the carotid sinus (e.g. during shaving or by tight collar) stimulates the baroreceptors in the carotid sinus  reflex ↑ vagal tone to the heart & ↓ sympathetic vasoconstrictor tone to the blood vessels  bradycardia (↓ HR) and hypotension ↓ ABP cerebral ischemia & momentarily loss of consciousness (fainting).
  • 32. Treatment: Denervation of the hypersensitive carotid sinus cures the condition. Clinical significance: Carotid sinus reflex could be used to terminate an attack of paroxysmal atrial tachycardia (PAT) but not of ventricular origin, as the vagus does not supply the ventricles.