أسئلة السابعة فسيو (بعد التعديل)

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Questions and Answers

What is the primary effect of sympathetic innervation on the heart?

Decreases heart rate

Inhibits contractility

Increases cardiac properties (correct)

Reduces blood pressure

Which ganglia are responsible for relaying sympathetic signals in the thorax?

Pelvic ganglia

Cervical ganglia and upper thoracic ganglia (correct)

Lumbar ganglia

Ciliary ganglia

What effect does sympathetic innervation have on bronchial muscles?

Inhibits bronchial muscles (correct)

Causes bronchoconstriction

Increases mucus secretion

Inhibit bronchodilation

What is the role of sympathetic nervous activity on the sphincter of Oddi?

Retains bile and delays emptying Signup and view all the answers

Which of the following effects is associated with sympathetic nervous system activation in the abdominal region?

Inhibition of digestion Signup and view all the answers

How does sympathetic innervation affect the lungs?

Induces bronchodilation Signup and view all the answers

What is the effect of sympathetic activity on glycogenolysis?

Increases glycogen breakdown for glucose release Signup and view all the answers

What is the impact of sympathetic nervous system on renal function?

Reduces renal blood flow Signup and view all the answers

What is the primary hormone secreted by the SRM cells?

Adrenaline Signup and view all the answers

In what way does adrenaline primarily function in the body?

Promotes metabolic actions Signup and view all the answers

Which ganglia relay nerve signals from the L1 to L3 segments?

Inferior mesenteric and hypo-gastric ganglia Signup and view all the answers

What effect does noradrenalin have on blood vessels?

Vasoconstriction Signup and view all the answers

What physiological effect occurs during stress conditions involving the sympatho-adrenal system?

Increased heart rate Signup and view all the answers

Which function is not associated with the sympathetic nervous system?

Stimulation of peristalsis Signup and view all the answers

How does the sympathetic nervous system affect the penis and clitoris?

Causes shrinkage Signup and view all the answers

Which region's sympathetic innervation primarily affects the ejaculation process?

Pelvic region Signup and view all the answers

What neurotransmitter primarily acts on blood vessels during sympathetic activation?

Noradrenalin Signup and view all the answers

What effect does sympathetic stimulation have on the bladder?

Promotes urine retention Signup and view all the answers

How does sympathetic activation affect sweat secretion in the skin?

Stimulates secretion Signup and view all the answers

Which segment of the spinal cord contributes to sympathetic innervation of the upper limb?

T2-T9 Signup and view all the answers

What is the primary action of adrenaline in the body according to the sympathetic nervous system?

Metabolic action stimulation Signup and view all the answers

Which of the following effects on cardiac properties is enhanced by sympathetic nervous activity?

Increased excitability Signup and view all the answers

What is the effect of sympathetic innervation on the secretion of bronchial mucus?

Decreases secretion Signup and view all the answers

What role do the inferior mesenteric and hypogastric ganglia play in sympathetic innervation?

They relay signals for the pelvic organs. Signup and view all the answers

Which sympathetic ganglia contribute to the innervation of thoracic organs?

Cervical ganglia Signup and view all the answers

What is the physiological effect of sympathetic activation on the internal anal sphincter?

Contraction Signup and view all the answers

How does the sympathetic nervous system affect the spleen?

Stimulate contraction of the splenic capsule Signup and view all the answers

What is the effect of sympathetic stimulation on glycogenolysis in the liver?

Increased glucose production Signup and view all the answers

During sympathetic activation, what happens to gastrointestinal organs?

Relaxation of walls and contraction of sphincters Signup and view all the answers

What physiological response is associated with sympathetic innervation in the kidney?

Stimulation of renin release Signup and view all the answers

Study Notes

Sympathetic Nervous System Innervation to the Thorax, Abdomen, and Pelvis

Origin of Thoracic Innervation:
- Upper 4 or 5 thoracic segments of the spinal cord
- Lateral horn cells
Relay of Thoracic Innervation:
- 3 cervical ganglia
- Upper 4 thoracic ganglia

Functions of Thoracic Sympathetic Innervation

Heart:
- Increases all cardiac properties:
  - Rhythmicity
  - Excitability
  - Conductivity
  - Contraction
- This increases the effectiveness of the heart as a pump
Coronary Vessels:
- Direct effect: vasoconstriction
- Indirect effect: vasodilatation (due to metabolite accumulation)
Lung:
- Bronchodilation due to inhibition of bronchial muscles
- Decreased mucus secretion due to inhibition of bronchial mucus glands
- Increased pulmonary ventilation capacity

Sympathetic Innervation to the Abdomen

Origin:
- Lateral horn cells of T6 - T12 segments of the spinal cord
- These are called Splanchnic Nerves
Relay:
- Collateral (Prevertebral) Ganglia
  - Celiac ganglia
  - Superior Mesenteric ganglia
  - Aortico-Renal ganglia
Functions:
- Increased glycogenolysis
- Increased glucose levels
- Increased fibrinogen synthesis
- Decreased endocrine and exocrine secretion
- Relaxation of the wall and contraction of the sphincter of Oddi, leading to bile retention and delayed emptying
- Contraction of the splenic capsule, pushing blood (250 ml) into circulation

Sympathetic Innervation to the Kidneys

Functions:
- Relaxation of the walls of the kidneys
- Contraction of renal sphincters
- Inhibition of digestion and delayed evacuation of kidney contents
- Stimulation of juxta glomerular cells results in increased renin production, which leads to vasoconstriction
- Decreased renal blood flow and decreased urine production
- Mixed supply of vasoconstriction and vasodilatation to the kidneys

Suprarenal Medulla

Origin:
- Lateral horn cells (LHCs) of T10 and T11 segments of the spinal cord
- Supplied by sympathetic preganglionic nerve fibers with no postganglionic nerve fibers
Relay:
- Directly relays with Suprarenal Medulla (SRM) cells (chromaffin cells)
Functions:
- Secretes adrenaline (80%) and noradrenaline (20%)
- Prolonged action due to slow clearance from circulation
- Adrenaline primarily acts on metabolic actions of the body
- Noradrenaline primarily acts on blood vessels
- In stress conditions, SRM works with the sympathetic nervous system (sympatho-adrenal system)

Sympathetic Innervation to the Pelvis

Origin:
- Lateral horn cells of L1 - L3 segments of the spinal cord
Relay:
- Inferior mesenteric and Hypo-gastric ganglia
Functions:
- Relaxation of the walls of the bladder
- Contraction of the internal urethral sphincter
- Decreased micturition (urination) and urine retention
- Relaxation of the walls of the rectum
- Contraction of the internal anal sphincter
- Decreased defecation (bowel movement) and stool retention
- Contraction of the seminal vesicles, leading to ejaculation
- Inhibitory effects on the uterus, but excitatory in late pregnancy
- Vasoconstriction (VC) leading to shrinkage of the penis and clitoris

Sympathetic Innervation Summary

Upper Limb:
- Origin: LHCs of T2 - T9
Lower Limb:
- Origin: LHCs of T10 - L2
Thoracic & Abdominal Walls:
- Origin: LHCs of T1 - L2
Functions:
- Skin: vasoconstriction of blood vessels, hair erection, sweat secretion
- Skeletal muscles: vasodilation of skeletal muscle blood vessels

Sympathetic Nervous System to Thorax, Abdomen, Pelvis

Origin: Lateral horn cells of the upper 4 or 5 thoracic segments of the spinal cord
Relay: 3 cervical ganglia and upper 4 thoracic ganglia
Functions:
- Heart:
  - Increases all cardiac properties: Rhythmicity, excitability, conductivity, contraction
  - Coronary Vessels:
    - Direct Effect: Vasoconstriction
    - Indirect effect: Vasodilation (due to accumulation of metabolites)
- Lung:
  - Inhibition of bronchial muscles: Bronchodilatation
  - Inhibition of bronchial mucus glands: Reduced mucus secretion
- Splanchnic Nerves:
  - Origin: Lateral horn cells of T6 to T12
  - Relay: Collateral (Prevertebral) Ganglia (Celiac, Superior Mesenteric, Aortico-Renal)
  - Functions:
    - Increased Glycogenolysis: Increased glucose
    - Increased Fibrinogen Synthesis
    - Decreased endocrine and exocrine secretion
    - Contraction of Splenic Capsule: Pushes blood to circulation (250 ml)
    - Relaxation of the wall and contraction of the sphincter of Oddi: Retention of bile and delayed emptying
- Kidneys:
  - Relaxation of walls, contraction of sphincters, inhibition of digestion, delayed evacuation of contents
  - Stimulation of juxta glomerular cells: Increased renin production, vasoconstriction
  - Decreased renal blood flow: Reduced urine production
- Adrenal Medulla (SRM):
  - Origin: LHCS of T10 & 11 segments of spinal cord
  - Relay: Supplied by sympathetic preganglionic nerve fibers, no postganglionic fibers, directly connected to SRM cells (chromaffin cells)
  - Function:
    - Secretes adrenaline (80%) and noradrenaline (20%)
    - Prolonged action due to slow clearance
    - Adrenaline acts on metabolic functions, noradrenaline acts on blood vessels
    - Sympatho-adrenal system: SRM acts together with sympathetic nervous system in stress conditions
- Pelvic Viscera:
  - Origin: Lateral horn cells of L1 to L3
  - Relay: Inferior mesenteric and hypogastric ganglia
  - Functions:
    - Bladder: Relaxation of wall, contraction of internal urethral sphincter, reduced micturition, urine retention
    - Rectum and Anal sphincter: Relaxation of the wall, contraction of internal anal sphincter, reduced defecation, stool retention
    - Seminal vesicles: Contraction, ejaculation
    - Uterus: Inhibitory effects on uterus, excitatory in late pregnancy
    - Penis and Clitoris: Vasoconstriction, shrinkage
- Skin:
  - Vasoconstriction of blood vessels, hair erection, sweat secretion
- Skeletal Muscles:
  - Vasodilation of blood vessels

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