Q 41 - 79 2nd Semester

Question 1

41. General description of regulatory mechanisms and their levels in a body.

Answer 1

• Regulation : Is the changing the course of any function or process with purpose to achieving a particular result

– we have two type of regulatory mechanism :
- nervous
Levels :
- central = by central neveous system
-Phriphral = by metasympathtic nervous system

• humoral
  Levels:
  General : hormonal
  Preiphral : paracrine

Question 2

42. Humoral regulation and it levels. A notion of a hormone, examples. APUD-system.

Answer 2

- - humoral : Its implemented though releasing regulatory substance into body fluid 
Ex- blood
Levels: 
General : hormonal 
Preiphral : paracrine

— Harmons is a substance secreted by glands if internal secetion into the blood stream , and its regulate the actevites of various ograns ans systems of whole body
Ex: Thyroid-stimulating hormone
– APUD-system. peripheral humoral regulation : Its carried out by APUD-System ,
APUD-system - its group of separately diffusely located secretory cells , which are present in larg numbers in practically all organs , and they are secret their secretes into inter cellular fluid of the given organ, and therefore can affect only the activates of this organ , and that’s method of regulation called paracrine regulation

Question 3

43. Nervous regulation and its levels, Notions of sympathetic, parasympathetic and metasympathetic nervous systems.

Answer 3

• nervous : It is implemented through the nervous system , using redlixes
  Levels :
• central = by central neveous system
  -Phriphral = by metasympathtic nervous system

— Vegtative nervous system:
Its system regulate the internal organs of the body
- Inclouding 3 parts
1- Sympataic nervous system – main : The part of the nervous system that increases heart rate, blood pressure, breathing rate,
( and its also responsible for Fight or Flight )
2- parasympathtic nervous system – main : Parasympathetic nervous system: The part of the involuntary nervous system that serves to slow the heart rate, increase intestinal and glandular activity, and relax the sphincter muscles.( its also responsible for rest and digest )
3-meta sympathatic nervous system (MNS) –sidly : The metasympathetic system attains the features of true autonomy. Its cells have no direct connection with the high centers: this connection is established through mono- and polysynaptic sensory and afferent units of sympathetic and parasympathetic nature.

Question 4

44. Comparison characteristic of somatic and vegetative nervous systems and their reflexes arcs.

Answer 4

—»»> draw the reflexs arcs of SoNS and VNS

—- Comparison characteristic :
1-higher centers :
-SoNS : higher Center is Cortex precebtral gyrus
-VNS : higher center is Hypothalmus

2- lower centers :

• SoNS : motornuoron is located in the Ant, horn
• VNS : the motornouron located in the latral horn of spinal cord or medulla oblangata

3 - motor Element :
-SoNs : its consist of 1 motor neroun and its located in Ant, horn
-VNS: its consist of 2 motor neroun
1 located in latral Horn
1 located out of CNS called ( vegtative ganglia )

4- mediator :

• SoNS : on Effector ( muscles ) Acyticholein ( ACH ) is Secreted
• VNS : imuplses transmission carried out by Acytilcholine (ACH )or noradrenalin (NA)

5- receptors :
-SoNS : on the effctor only N-cholinorecptor (N-h/r)
-VNS : on the 2nd motorneourn N-cholinorecptor , and on the effctor ethier
M-cholinoreceptor or adrenorecptor ,

6 - segmntal metamaric :
-SoNS : somatic nerve Fibers leave the spinal cord segmentally and overlap with innervating at least 3 nighbouring metamers
-VNS : has no prenciple of segmental meatmaric innervation
VNS fibers go from 3 sites
- brain stem -thoracolumbr - sacral part
Then they distrbute on prephry and is consederd to be deffuse, they innervates the all vescral systems without any exeption which in the most cases have sympathatic and parasympathatic innervation

7 - Effector :

• SoNS : effector is the skelatal muscles
• VNS: effector is ethier 1 smooth muscles 2 cardiac muscles 3 gland

8- functonial deffrencises :

• SoNS : regulate the tonic actevity of the skelatel muscles
• VNS : alters the actevtiy of the internal organs

9 -voronterness :

• SoNS : volontrely , you can change the toinc of the skelatel mucles
• VNS : unvolontry , volontrness of VNS is extremly low , however using somw Yoga training you can achive some missur of controling over the actevty if internal organs

Question 5

45. Somatic, sympathetic and parasympathetic reflexes arcs. Examples of such reflexes.

Answer 5

> > > > > > draw the SoNS + PNS + SyNS reflex arcs
- examples :
1- Sons : such as arm withdrawals upon finger pricks
2-PNS : secretion of Saliva
3-Syns : sensory impulses from thermal or pain receptors

Question 6

46. Receptors and mediators of somatic and vegetative reflexes arcs on their moto- and effector elements.

Answer 6

— receptors :
-SoNS : on the effctor only N-cholinorecptor (N-h/r)
-VNS : on the 2nd motorneourn N-cholinorecptor , and on the effctor ethier
M-cholinoreceptor or adrenorecptor ,

• • mediator :
• SoNS : on Effector ( muscles ) Acyticholein ( ACH ) is Secreted
• VNS : imuplses transmission carried out by Acytilcholine (ACH )or noradrenalin (NA)

Question 7

47. Segmental-metameric principle of somatic innervation. Diffuse location of vegetative fibers

Answer 7

• —– segmntal metamaric :
• SoNS : somatic nerve Fibers leave the spinal cord segmentally and overlap with innervating at least 3 nighbouring metamers

-VNS : has no prenciple of segmental meatmaric innervation
VNS fibers go from 3 sites
- brain stem -thoracolumbr - sacral part
Then they distrbute on prephry and is consederd to be deffuse, they innervates the all vescral systems without any exeption which in the most cases have sympathatic and parasympathatic innervation

—– Fiber diffusion
– Sympathetic nervous system :
- fibers originate from : thoracic and lumber region of spinal cord
It has short preganglionic and long postganglionic fibers
- the ganglia is near to spinal cord
–Parasympathetic nervous system :
- Fibers oregnate from: Brain or sacral region of the spinal cord
- it has long pergangloinc and short postganglionc fibers The ganglia in the effector organs

Question 8

48. Functional differences between somatic and vegetative nervous systems and their reflexes arcs. Somatic nervous system voluntariness. Examples of somatic vegetative reactions.

Answer 8

– Functional differences between somatic and vegetative nervous systems
-SoNS : regulate the tonic activity of the skeletal muscles
-VNS : alters the activity of the internal organs
—-voronterness :
-SoNS : volontrely , you can change the toinc of the skelatel mucles
-VNS : unvolontry , volontrness of VNS is extremly low , however using somw Yoga training you can achive some missur of controling over the actevty if internal organs
——
Ex of the somtaic vns reaction
such as pulling one’s hand away after touching a hot stove

> > > > draw the reflex’s arcs

Question 9

49. Comparison characteristic of sympathetic and parasympathetic nervous systems. Their reflexes arcs, receptors and mediators.

Answer 9

— Comparison characteristic :
-1 higher center :Higher centre of VNS is the hypothalamus
-SoNs :Its posterior (as well as lateral) nuclei are higher sympathetic centers called ergotropic (from Greek ergon – action; + tropos – direction).
-VNS: In the front area of the hypothalamus (and in preoptic area) higher parasympathetic nuclei or trophotropic (from Greek trophe – food) nuclei are located.
2- lower center:
SoNS:In SyNS the first motoneurons are located in lateral horns of the spinal cord, in CVIII – LI (or LIII).
VNS:PNS nuclei are located in the midbrain (oculomotor nerve), pont, medulla oblongata (facial, glossopharyngeal and the vagus nerves) as well as in lateral horns of the sacral segments, SI – SIII.

> > > ## draw the reflex arcs OF PNS and Syns–receptors and mediators. :
- in the PNS and SyNS between the first ans second motornouron the mediator is ACH ( acytaicholin ) secreted and in the 2nd motor nuorun N-cholenorecptor is located

• SyNS : in the effector organ noraladrenalin released and the receptor is adrenorecptor (a/r)
• PNS: in the effector organ ach ( acytaicholin ) released and the receptor on the effector organ is M-choleinoreceptor

Question 10

50. Main sympathetic and parasympathetic centers

Answer 10

-1 Higher center

• Syns : The higher center of the VNS is the hypothlamus
• in the post, ( as well as latral ) the higher nuclei of the sympathatic and its called Ergotropic

-PNS:The higher center of the VNS is the hypothalmus
- in the front area of the hypothlamus the higher nuclei of the parasympathtic located
And its called trophotropic
-2 Lower center :

-Syns : The first motorneurons are located in the latral horn of the spinal cord
(C8-L1or L3 )
-Main syns centers
The center of (C8-Th1 or Th2 ) segaments make widning the pupile (mydriasis )
Expanding the eye fissuer and cousing protubrance of the eye ball (proptosis or exophtalm) they implement this effect with the perticapation of the cervical sympathatic ganglion or (cervical sympathatoc nodes )

-PNS : In PNS nuclei are located in the mid brain ( oculomotor nerve ) pons medulla oblongata ( facual , glossophryngeal , vagus nervs as well as in latral horn of the sacral segments S1-s3
-Main parasympathatic centers Of PNS are located in 3 deferent areas of the CNS
1 mid brain
2 medulla oblongata
3 Sacral part of the spinal cord

Question 11

51. Functional differences between sympathetic and parasympathetic nervous systems. Examples of their

Answer 11

• Function is the main difference between Syns and pns

—– -SyNS : its Fight or flight
the usefulness of the SyNS existence to the nervous system if stress
Changes in the activity if internal organs which are needed in the stressful situations occur when the tone of syna rising
Ex : the story of the elephent

-PNS its rest and digest
is a nervous system of rest
Pns provides restoration of a body energy resources which spent by Syns un the state if considerable physically , mental or emotional stress
Ex : the story of the elephent

Question 12

52. Antagonistic relationship of sympathetic and parasympathetic nervous systems. Their influence on antagonistic relationship reactions. various organs.

Answer 12

— the principle of antagonism in relations between sympathetics and parasympathetics: these two parts of VNS have opposite, oppositely directed effects on a specific organ(s)
- Such organs :
1- heart :
-Syns: increase in the strength and frequency of contraction and enhancemnet of condeuctivity and excitabilty
PNS: decrease in strength and frequoncy of contracton and reducton of conducdtivity and excitablity
2-slaivary glands :
Syns: stamulaiton of the enzyme (frement ) production
Pns : stamulation if watre and hydrocarbonet prodction
3-cornary artery :
Syns : dilation
Pns: contriction
4-respiratory mc breathing :
Syns: stimulation
Pns: suppression

Question 13

53. Sympathetic and parasympathetic influences on different organs. Examples of such reflexes.

Answer 13

1- heart :
-Syns: increase in the strength and frequency of contraction and enhancemnet of condeuctivity and excitabilty
PNS: decrease in strength and frequoncy of contracton and reducton of conducdtivity and excitablity
2-slaivary glands :
Syns: stamulaiton of the enzyme (frement ) production
Pns : stamulation if watre and hydrocarbonet prodction
3-cornary artery :
Syns : dilation
Pns: contriction
4-respiratory mc breathing :
Syns: stimulation
Pns: suppression

Question 14

54. Concepts of both antagonism and synergism relations between vegetative nervous system parts. Examples.

Answer 14

These two systems do not fight each other, but solve one common problem – the most accurate adaptation of the organism to conditions of external environment constantly changings.

Question 15

55. Respiration and its stages

Answer 15

— Respiration : is the process of oxygen and car-oxygen exchange between the atmosphere and body tissue
— Stages :
1-external breathing (exchange of gases between the atmosphere and lungs )
2-gases diffusion throughout aerohematic barrier
(Between alveoli and blood )
3-transport of gases
4-diffusion of gases through the capillaries walls
(Between blood and tissue)
5 - internal breathing , oxidative reaction in the cell ( mitochondria)

Question 16

56. Transpulmonary pressure, its formation and significance. Other forces influencing on lungs excursion.

Answer 16

• 1- transpulmonary : Its gradient of pressure between the pleural cavity and alveolar
• • formation of transpulmonary : Since the parietal pleura is attached to the thoracic wall, the natural elasticity of the chest wall opposes the inward pull of the lungs. Ultimately, the outward pull is slightly greater than the inward pull, creating the –4 mm Hg intrapleural pressure relative to the intra-alveolar pressure.
• significance. :the transpolmonary pressure which is always directed from alveoli to the pleural cavity from inside to out side and aims to expand the lungs
• ——Other forces influencing on lungs excursion.
• 2 - the elastic recoil of the lungs Which aims to compress the lungs
• If these 2 forces are equal thats mean the lung doesn’t move

Question 17

57. The mechanism of quite in- and exhalation.

Answer 17

-1- mechanism of inhalation :
Start with reducing inspiratory mc , the pleural cavity expands and the it pressure get even more negative , transpolmonary pressure increases and elastic recoil of the lungs becomes greater , the lungs expands , air enters inhalation takes place
-2-exhalation mechanism:
its begins with relaxation of the inspiratory mc , in this case , due to gravity the thorax is lowered, pleural cavity decreases , and it pressure get even less negative , the transpolmonary pressure decreases and becomes less then the elastic recoil
And because id the action if the lungs parenchyma subside and exhalation takes place

Question 18

58. Aero-hematic barrier, surfactant. Their significance for breathing.

Answer 18

• Aero-hematic barrier : The blood–air barrier or air–blood barrier, (alveolar–capillary barrier or membrane) exists in the gas exchanging region of the lungs. It exists to prevent air bubbles from forming in the blood, and from blood entering the alveoli.

-surfactant : Its a think layer of liquid , which the alveoli are covered from the inside
And bcs its liquid, it has the force of surface tension And this force its the main component of the elastic recoil of the lungs And the function of it to squeeze the lung on the other side it has low density and accordingly has low surface tension

Question 19

59. A content of gases in different environments: atmospheric and alveolar air, arterial and venous blood.

Question 20

60. Gases transport substances (forms of gases transport). Gas exchange reactions at lung’s level.

Answer 20

-  ways transporting of o2 
1- in dissolved form 
2- in connection with Hb which named
Oxyhemoglobin
-ways transporting of Co2
1- in dissolved form 
2- in connection with Hb which named 
Carbhemaglobin
3- in form of  acidic salts of carbonic acid 
Ex: hydrocarbons and potassium and sodium3

> > > > draw the scheme of reaction of lungs level

Question 21

61. Gases transport substances (forms of gases transport). Gas exchange reactions in tissues.

Answer 21

-  ways transporting of o2 
1- in dissolved form 
2- in connection with Hb which named
Oxyhemoglobin
-ways transporting of Co2
1- in dissolved form 
2- in connection with Hb which named 
Carbhemaglobin
3- in form of  acidic salts of carbonic acid 
Ex: hydrocarbons and potassium and sodium3

> > > > draw the scheme of reaction of tissue level

Question 22

62. Three types of a cardiac muscle cells. Cardiac conductive system.

Answer 22

• cardiac muscle cells
  1- contractile : Contractile ( typical , working ) cardiomyocytes they make up 99% of myocardium mass , - all these cardiomyocytes are interconnected by nexuses A nexuses has a low threshold (high excitability) so excitement of one cardiomyocytes will necessarily cause excitement on neighbouring ones and further to all other cardiomyocytes which will cause contraction of the whole myocardium therefore syncytium

2- conductive : Conductive (atypical , specilazed ) cardiomyocytes are practically unable to contract and make prat of the conductive system , that means they perform the function of neurons

Cardiac conductive system. : conductive system of the heart generating in the heart its own impulsion and transmitting these impulses on contractile cardiomyocytes, that means they perform the function of neurons

Question 23

63. Specific properties of the cardiac muscle, mechanisms of this features.

Answer 23

1-Automatism : Its the ability to get self excitement Without getting outside cell irritation from neurons ,
- automatism if the cardiac muscle is extremely high , a heart removed from the body ( in virto ) continues to contract , this is provided by which so called diastolic depolarisation if atypical cardiomyocytes

2- long refectory period : Action potential of cardiomyocytes lastes 0,3 sec , plateau phase takes 0,27 sec and therefore almost for the whole time if action potential generation a cardiomyocytes is in a state if absolute refractoriness
- that’s mean if there is another irritation even suprathreeshould one there will be no additional contraction , each subsequent contraction starts only after the contraction to previous irritation finish

3- inability to tetanic contraction : Is the ability to contracts for long term without complete relaxation in response to a series stimuli

4- functioning by the principal- all or nothing : a cardiac muscle in contrast to a skeletal one reacts to the stimuli according to the principal “ all or nothing “ in response to a subthreshold irritant the heart muscle doesn’t respond to a threshold stimulus a cardiac muscle responds by contraction to the maximum strength which it is able to develop because all the myofibrils are involved inti this reaction

Question 24

64. Cardiomyocyte action potential, its differences from an action potential of a skeletal muscle cell.

Answer 24

— Cardiomyocyte action potential, : like any excitable cell , Cardiomyocyte have excitability - generation of action potential - conductivity - contractility which these 3 are the non-specific properties of the cardiac muscle

> > > > draw the heart AP Curve

—- differences from an action potential of a skeletal muscle cell.
1- the absence of slow depolaraztaion phase ( depolarization is only one stage and always complete )
2- depolarization developed not by sodium but by calcium ( sodium poorly effect the heart but calcium preparations can alter significantly its activity.
3- Repolarization develops in 3 stages ( initial stage is quick , then plateau phase , and the final one is quick )
4- long action potential ( the action potential of the cardiac muscle lasts 0,3 sec (300ms) , the action potential of the skeletal muscle only 0,003 sec (3ms)

Question 25

65. Long refractoriness of a cardiac muscle and its mechanism. Mechanism of diastolic

Answer 25

- Long refractoriness : Its inability to respond to additional irritation Action potential of cardiomyocytes lastes 0,3 sec , plateau phase takes 0,27 sec and therefore almost for the whole time if action potential generation a cardiomyocytes is in a state if absolute refractoriness - that's mean if there is another irritation even suprathreeshould one there will be no additional contraction , each subsequent contraction starts only after the contraction to previous irritation finish ------- - Mechanism of diastolic : Even at rest The diastole , part of sodium channel atypical cardiomyocytes remains partially open , a slow entry of sodium and slow depolarization are observed, as soon as it reach the critical level , generation of completed action potential take place , thus atypical cardiomyocytes differ from contractile ones in that they have slow depolarization phase called the diastolic depolarization

Question 26

66. Heart as a functional syncytium, work according to the principle "all or nothing". depolarization.

Answer 26

-- Syncytium in human heart have two portion 1- syncytium of atria 2- syncytium of ventricles Both portions if syncytium are connected by a thick non-conducting fibrous ring called - atrioventricular ring - in organism only the heart works as the functional syncytium , heart is tissue which mean a group of cells but works like all together one cell --functioning by the principal- all or nothing : a cardiac muscle in contrast to a skeletal one reacts to the stimuli according to the principal “ all or nothing “ in response to a subthreshold irritant the heart muscle doesn’t respond to a threshold stimulus a cardiac muscle responds by contraction to the maximum strength which it is able to develop because all the myofibrils are involved inti this reaction --depolarization : Even at rest . The diastole , part of sodium channel atypical cardiomyocytes remains partially open , a slow entry of sodium and slow depolarization are observed, as soon as it reach the critical level , generation of completed action potential take place , thus atypical cardiomyocytes differ from contractile ones in that they have slow depolarization phase called the diastolic depolarization

Question 27

67. Phases of the cardiac cycle.

Question 28

68. Mechanical functioning of the heart. Mechanical cardiogram. Phases of cardiac cycle and their durations

Question 29

69. Atrial cycle. Frank-Starling law.

Answer 29

--- Atrial cycle : systole 0.1 sec , diastole 0.7 therefore implementation by ventricles --frank starling law : The more cardiomyocytes is stretched in the diastole , the more it will contract on the systole

Question 30

70. Ventricular cycle. Its phases and their purposefulness

Question 31

71. Cardiac volumes

Answer 31

--- each chamber of the heart has its own volume 1- Stroke Volume ( SV) : amount of the blood ejected by heart into aorta or or pulmonary artery , for the left ventricles it makes 70ml 2-minute volume of bloodstream (MVB) : its the amount ejected by the heart into the pulmonary or systemic circulation per minute its formula (MVB = SV * heart rate ) So 70mL * 70 heart rate per minute = 4900ml/min so the intensity of the circulation in the systemic circulatory system its approximately 5L/ min 3- Final diastolic vloume (FDV) : its the maximum amount of the blood in heart chamber at the end of diastole . for the left ventricle its 140ml , and for athlete it could reach 300-350ml , however if the value increased this is pathology associated with heart failure called bullcardia and its formula FDV=SV+RvV+RIV 4-reser volume (RvV) : its the amount of the blood that a ventricle can ejection exertion its makes about 20% of the FDV 5-Risdual Volume (RIV) : its the amount left in ventricle at the end of systole and its make about 30% of the FDV

Question 32

72. Levels and mechanisms of cardiac activity regulation. General description.

Answer 32

``` -1- intercardiac : relating to the mechanism which are appears and situated within the heart And its 4 mechanism: 1-interacellular 2-extracellular 3-neuronal 4- humoral ``` -2- extracardiac : relating to the mechanism, tissue , cells , organs which are all involved directly or indirectly in the regulation of heart and situated outside the heart And its 2 mechanism: 1- neuronal 2- humeral

Question 33

73. Intra- and extracellular mechanisms of cardiac activity regulation.

Answer 33

- ---interacellular : - 1- hypertrophy : its the enlargement of myocard from the increase in size of its cells as a result of increasing a number of contractile proteins ( actin and myosin ) or cardiomyocytes in whole -2- atrophy : its opposite process waste away , especially as a result of contractile proteins degeneration or cardiocytes number decreasing - 3- direct dependence of strength on the rate : - the high frequency of the heart contraction dose not allow its sarcomeres ( during diastole ) to pump the calcium from the sarcoplasm of the calcium depots - thus each following contraction ( in systole) begins in condition of increasing of calcium contraction in sarcoplasm - so the higher amount if calcium results in the higher amount of energy in each if the sarcomere, this increases the myocardium activity 4- frank starling law : - the strength of the contraction of muscle ( cardyocytes ) is directly promotional to an expansion of this muscle during its previous relaxation and physiological importance is Its lies mainly in the maintaining left and right ventricular output equality 2-extracellular : -syncytium : Its mean tissue with cytoplasmic continuity between adjacent cells Cardiac muscle is like a physiological syncytium since there is no continuity of cytoplasm and the muscles fibers are separated from each other by cell membrane - so extracellular regulation realizes due to a nexus : special electrical gaps of cardiomyocytes which have a low threshold level , if at any reason nexuses change there threshold so an excitability of the whole myocardium will change oppositely , and in appropriate manner will change the activity of the heart --Syncytium in human heart have two portion 1- syncytium of atria 2- syncytium of ventricles Both portions if syncytium are connected by a thick non-conducting fibrous ring called - atrioventricular ring - in organism only the heart works as the functional syncytium , heart is tissue which mean a group of cells but works like all together one cell

Question 34

74. Intracardiac reflexes. Intracardiac humoral regulation.

Answer 34

---- Intracardiac reflexes: - A bainbridge reflex is an increasing of strength of the left ventricle upon a increase of venous return to a right atrium, and its carried out by cardio-cardiac reflex - the bainbridge reflex is triggered when the stretch receptor in the atria are triggered that's mean that there is an increased level of venous blood return - So higher the venous return to right atrium higher contraction of left ventricle ---Intracardiac humoral regulation. : realized due to 3 things 1- accumulation of metabolites during intensive heart working like : Co2,H+,Lactic acid , H2CO3 2- blocking of à-adrenoreceptor 3-cardiac stimulation

Question 35

75. Vegetative regulation of a heart.

Answer 35

- Parasympathetic centres locate only in medulla oblongata , there influences are realising by vagus which innervates nods of the heart conductive system and contractile myocardium of auricles — Parasympathetic innervation vagus and Dorsal nucleus , - preganglionic fibres of vagus arises from the neurons of C.I.C ( cardiacinhibatory center ) they reach the heart as pregangiloinc fibres and relay in terminal ganglia present in the substance of the atrial muscle particularly the nodal tissue -postganglionic fibres supply sina atrial node and Atrioventricular node and main stem of the Atrioventricular bundle and atrial muscle, coronary blood vessels . - vagus nerve dont supply the ventricles or branches of Atrioventricular node and purkinje fibres -- - Sympathetic centers lay both in medulla oblongata and in upper thoracic segments of spinal cord , and its fibres innervate nodes of conductive system of the heart and contractile cardiomyocytes - its begins at C.A.C ( cardiac accelerator center ) in medulla oblongata near CIC ( cardiacinhibatory center ) the axons of there neurons descend in the white matter of the spinal cord , and relay at L.H.C ( latral gray column ) of upper 5 thoracic segments - pregangiloinc fibres of lateral horn pass in sympathetic chain and ascend upward to relay in the three cervical sympathetic ganglia ( sup , inf , mdl , cervical sympathetic ganglia) - postgangiloinc fibres pass from the ganglia to the heart and innervating all the structure including the ventricles

Question 36

76. Extracardiac humoral regulation. It differences from an intracardiac one

Answer 36

--- first of all extracardiac humoral regulation is realized duo to : 1-metabolites 2- Gases 3- electrolytes 4- hormones ------ by metabolites : Its realizes the same way in the intercardiac which 1- accumulation of metabolites during intensive heart working (Co2,H+,lactic acid,H2Co3) 2-blocking of a-adrenoreceptor 3-cardiac stimulation -------by gases 1- O2: For the O2 Hyperoxia : occurs when cells or tissue or organ are exposed to an excess supply of oxygen or higher then normal partial pressure of oxygen - its stimulates by oxygen of chemoreceptors of vesicular reflexoginic zones and the resulting of suppression of SyNS and activation of PNS - and its has negative effects in the heart 2-Co2 : For the Co2 Hypercapnia : its condition of abnormally elevated carbon dioxide levels in the blood - Its also known ( hypercarbia , Co2 -retention) - stimulation by Co2 of chemoreceptors of vascular reflexogainc zones and its result activtion of SyNS and decreasing of PNS tonus . - it has positive chronotropic effect ------by electrolytes : -( sodium ) : -sodium has positive chronotropic action because it takes part in depolarisation The low level of sodium ion in body fluids reduces the electrical activity if cardiac muscle and electrocardiogram shows low-voltage waves - condition of sodium in body — Hypernatremia : tachycardia - is a heart rate that exceeds the normal resting rate —Hyponatremia : bradycradia - decreasing of heart rate under 60 beats per minute - ( potassium ) : - potassium hall all 4 negative action — condition of potassium : - hypokalaemia : has some low influence of increasing the sensitivity of heart muscle, but mainly results in critical changes in heart activity -hyperkalemia : may be dangerous in its higher concentration changes 1- resting membrane potential is leading to hyperpolarazation 2-Excitability of the cardiomyocytes decreases -(calcium) : —hypercalcemia : 1- improves electromechanical conjugation by : activates phosphorylase ATP dissociation output of an energy for myosin heads turning / positive inotropic effect 2-increasing of myocardium depolarisation positive chronotropic effect —hypocalcemia : reducing diastolic depolarisation which decreases the excitability of heart muscle Which is negative bathmotropic effect —-an overdose of calcium drugs which are widely used in different medicine areas may be extremely dangerous ----- By hormones' : -Adrenaline stimulates B-receptor adrenaline and noradrenaline stimulate heat activity and cause positive regulatory effects : 1- positive inotropic 2- positive chronotropic -thyroid hormones : -The hormones that secreted by thyroid its the thyroxin -1-thyroxin increase the sensitivity of the heart to action of adrenaline -2- and increasing protien synthesis in the heart by stimulation of intercellular enzyme — the results of this hormone effect is positive chronotropic effect ------ differences from an intracardiac one : the difference between them its from where these substances got to the heart 1- if its was appeared inside the heart and stimulate it activity then its intercadiac regulation 2-if its appeared in some other organ like contracted striated muscle or digestion system and got to the heart with blood flow then it will be Extracardiac regulation

Question 37

77. Different extra reflexes on a heart activity.

Answer 37

- Bainbridge reflex: is one of the intracardiac neural mechanism - baroreceptor reflex: its one of the extracardiac mechanism -The relationship between them is antagonistically that's mean if venous blood pressure in atrium is much changing the Bainbridge reflex is dominant , and if for example the carotid artery baroreceptor indicates much arterial blood pressure chaining that's mean baroreceptor is dominant

Question 38

78. Vascular reflexogenic zones. Influences on a heart activity from other organs. Brain cortex regulation of a heart work.

Answer 38

- The main two zones are 1- Sino-carotid zone 2- aortal arch zone - The vascular reflexogainc zone has 2 types of receptors 1-Baroreceptors 2- chemoreceptors -- These receptor dampens the short-term fluctuations in blood pressure by feedback modulation of heart rate (HR) and vascular resistance they have a much influence on controlling the blood pressure ----------- - Brain cortex regulation of a heart work. - Vital centres of medulla oblongata have both 1-Cardioaccelerator center :which activities sympathetic neurones that increases the HR ( heart rate ) 2-cardioinhibatory centre : which activate parasympathetic neurons that decreases the HR — cardiac center receive input from higher centre which is the hypothalamus monitoring the blood pressure and dissolved gas concentration The afferentation for this reflex forms from 1- the circulatory system 2- other body parts ------- -Influences on a heart activity from other organs. : such as -The hormones that secreted by thyroid its the thyroxin -1-thyroxin increase the sensitivity of the heart to action of adrenaline -2- and increasing protien synthesis in the heart by stimulation of intercellular enzyme) — the results of this hormone effect is positive chronotropic effect .

Question 39

79. Influences on a heart activity by changes in plasma of electrolytes content. Its clinical significance.

Answer 39

----- electrolytes : -( sodium ) : -sodium has positive chronotropic action because it takes part in depolarisation The low level of sodium ion in body fluids reduces the electrical activity if cardiac muscle and electrocardiogram shows low-voltage waves - condition of sodium in body — Hypernatremia : tachycardia - is a heart rate that exceeds the normal resting rate —Hyponatremia : bradycradia - decreasing of heart rate under 60 beats per minute - ( potassium ) : - potassium hall all 4 negative action — condition of potassium : - hypokalaemia : has some low influence of increasing the sensitivity of heart muscle, but mainly results in critical changes in heart activity -hyperkalemia : may be dangerous in its higher concentration changes 1- resting membrane potential is leading to hyperpolarazation 2-Excitability of the cardiomyocytes decreases -(calcium) : —hypercalcemia : 1- improves electromechanical conjugation by : activates phosphorylase ATP dissociation output of an energy for myosin heads turning / positive inotropic effect 2-increasing of myocardium depolarisation positive chronotropic effect —hypocalcemia : reducing diastolic depolarisation which decreases the excitability of heart muscle Which is negative bathmotropic effect —-an overdose of calcium drugs which are widely used in different medicine areas may be extremely dangerous ----- By hormones' : -Adrenaline stimulates B-receptor adrenaline and noradrenaline stimulate heat activity and cause positive regulatory effects : 1- positive inotropic 2- positive chronotropic -thyroid hormones : -The hormones that secreted by thyroid its the thyroxin -1-thyroxin increase the sensitivity of the heart to action of adrenaline -2- and increasing protien synthesis in the heart by stimulation of intercellular enzyme — the results of this hormone effect is positive chronotropic effect