قناة سنة ثانية بشري (دفعة 53)

Generalized Sympathetic (Stress) Response • ↑ O₂ supply (bronchodilation) • ↑ glucose + ↑ free fatty acids • ↑ heart output & BP • Redistribution of blood to muscles • ↑ muscle strength & delay of fatigue • ↑ alertness via adrenal catecholamines • ↑ sweating for heat loss Main Sympathetic Effects (Receptors) • Eye: Mydriasis (α1) • Heart: ↑ HR & contractility (β1) • Bronchi: Bronchodilation (β2) • Liver: Glycogenolysis (β2) • Fat: Lipolysis (β3) • Vessels: • Skin/viscera → VC (α1) • Skeletal muscle → VD (β2) Horner’s Syndrome Damage to cervical sympathetic pathway → same-side effects: • Miosis • Ptosis • Anhydrosis • Vasodilation • Enophthalmos

Sympathetic Effects Head & Neck • Pupil dilation (mydriasis) • Eyelid elevation • Exophthalmos • Skin vasoconstriction, sweating, hair erection • Thick, enzyme-rich salivary secretion Thoracic Viscera (T1–T4) • Heart: ↑ HR, ↑ force, ↑ conduction • Lungs: Bronchodilation Abdominal Viscera (T5–T12) • GIT: ↓ motility, ↑ sphincter tone → food retention • Liver: Glycogenolysis → ↑ glucose • Spleen: Capsule contraction → ↑ blood volume • Kidneys: ↑ Renin release • Adrenal medulla: Secretes adrenaline (80%) & noradrenaline (20%) Pelvic Viscera (L1–L2) • GIT: Retention of feces • Urinary bladder: Retention of urine • Genital system: Ejaculation • Penis/clitoris: Vasoconstriction → shrinkage Limbs & Body Wall • Skin vasoconstriction • Sweating • Hair erection • Vasodilation in skeletal muscles

The Autonomic Nervous System (ANS) controls involuntary body functions and regulates internal organs. It operates through autonomic ganglia, sympathetic nerves, and parasympathetic nerves to maintain homeostasis. 1. Autonomic Ganglia Autonomic ganglia are clusters of neurons located outside the CNS, where: • Preganglionic fibers (ACh-releasing) synapse with • Postganglionic autonomic fibers. They serve as relay and distribution centers for autonomic signals. Types of Autonomic Ganglia 1. Lateral (Paravertebral) Ganglia • Form the sympathetic chain (23–25 ganglia). • Carry only sympathetic fibers. 2. Collateral (Prevertebral) Ganglia • Include celiac, superior mesenteric, renal, and inferior mesenteric ganglia. • Relay sympathetic + some parasympathetic fibers. 3. Terminal Ganglia • Located near or inside target organs. • Relay only parasympathetic fibers. Neurotransmission • ACh is released from all preganglionic fibers (symp + parasymp). • One preganglionic fiber may synapse with: • 20+ postganglionic fibers → sympathetic, widespread effects. • 2 postganglionic fibers → parasympathetic, localized effects. 2. Interaction Between Sympathetic & Parasympathetic Systems 1. Reciprocal action: one activates, the other inhibits. 2. Antagonistic action: e.g., pupil dilation vs constriction. 3. Cooperative action: sexual function (erection vs ejaculation). 4. Complementary action: salivation—PNS ↑ volume, SNS ↑ enzymes. 3. Origin of the ANS • Sympathetic (Thoracolumbar): T1–L2 segments. • Parasympathetic (Craniosacral): Cranial nerves III, VII, IX, X + S2–S4 segments.

🟡 2 . Autonomic Nervous System (ANS): ⬇️⬇️⬇️⬇️

الشيت الأول كمل ي شباب 🔥🔥♥️. منتوقعش يجي منه شورت نوت بكل .

نتعشى ونجيكم 🥲🥲💔.

Overview of the Nervous System The nervous system is divided into: 1. Central Nervous System (CNS) • Composed of the brain and spinal cord • Responsible for processing information and coordinating body functions 2. Peripheral Nervous System (PNS) • Consists of nerves extending from the CNS to the rest of the body • Subdivided into: • Afferent (Sensory) System: Carries information to the CNS • Efferent (Motor) System: Carries commands from the CNS to muscles and glands Motor (Efferent) System Subdivisions 1. Somatic Nervous System • Voluntary • Controls skeletal muscles 2. Autonomic Nervous System (ANS) • Involuntary • Controls smooth muscle, cardiac muscle, and glands • Divided into: • Sympathetic System: “Fight or flight”; generally increases organ activity • Parasympathetic System: “Rest and digest”; generally decreases organ activity • Enteric System: Regulates gastrointestinal function Cranial and Spinal Nerves Cranial Nerves (I–XII) Include nerves responsible for smell, vision, eye movement, facial sensation, taste, hearing, balance, swallowing, heart regulation, and tongue movements. Spinal Nerves Carry sensory (afferent) signals to the CNS and send motor (efferent) signals to muscles and glands. Transverse Section of the Spinal Cord Contains: • Gray Matter: • Dorsal horn • Lateral horn • Ventral horn • White Matter: • Dorsal columns • Lateral columns • Ventral columns • Central Canal • Spinal Nerve Roots: • Posterior (sensory) • Anterior (motor) Neuron Structure A neuron consists of: • Dendrites (receive signals) • Cell body (soma) with a nucleus • Axon (conducts impulses) • Myelin sheath (insulation) • Nodes of Ranvier (speed conduction) • Schwann cells (produce myelin) • Axon terminals (transmit signals) Reflex Arc A basic neural pathway that controls reflex actions. Steps include: 1. Receptor: Detects the stimulus 2. Afferent Pathway: Carries sensory input to the CNS 3. Control Center: CNS processes the information 4. Efferent Pathway: Motor signal sent from CNS 5. Effector: Muscle or gland responds Somatic reflexes act on skeletal muscles Autonomic reflexes act on smooth muscle, cardiac muscle, and glands Neurotransmitters used: • Somatic: Acetylcholine (ACh) • Autonomic: ACh & Norepinephrine (NE) Overview of the ANS • Involuntary system regulating internal organs • Sympathetic and parasympathetic divisions often have opposite effects • Maintains homeostasis and responds to stress

والله عارفكم حايسيين والله ما نردكم توا نلخصوه الكورس وركزو معايا بيش تعرفو الشورت نوت المتوقعات . ادعولي نتزوجها بس مانبش شي 😂😂♥️.