#Israel_against_humanity
#stopinvasion
New scenes documenting the massacre of hundreds of martyrs and wounded in the courtyard of the National Arab Hospital in Gaza after the Israeli occupation aircraft bombed the hospital. It is noteworthy that the hospital contained thousands of displaced people after the occupation asked them to evacuate their homes. 🇵🇸... This is the real Holocaust.”

If you are a human being, come out now to denounce the massacre committed by the Israeli occupation against the Al-Ahly Arab Hospital in Gaza, which resulted in the death and injury of hundreds of civilians. .

Free palastine 🇵🇸

همُ الأحرارُ ونحنُ الأسرىٰ، همُ الأعزاءُ ونحنُ الأذلَّاء، نحنُ مَن يحتاجُ إلىٰ مِنهاج تربيتِهم ونصرتِهم وعزتِهم وتقواهُم وصبرهِم وبأسِهم وإيمانِهم، نحنُ المَغلوبون العَاجزون المكبَّلون النائِحون، وهمُ المناضِلون الصَّامدون الثابتُون علىٰ الحقِّ والدِّين والأرضِ ولَو تكالبَ العالمُ بأسرهِ عليهِم، إنمَا نحَاول اللحاقَ بركبهِم لعلَّ يصِيبنا مِنهم بَعض الشجاعةِ والعزةِ والمَجد. 🤍

- لِقائله.

جـــدول مقارنه بين ڪل ٲنـــواع النقل اللي شرحناها😊

💢مفاجأة كبرى و اشتراك مجاني
لشرح الطب بطريقه جديده وسهله وغير ممله
قناة مهتمه بالطب الباطني وطب الأطفال
❕عندك خوف من أسئلة الشفوي
❕مش قادر ترتب معلومات النظري
❔ حالات و MCQ
كل ما عليك الاشتراك
@easymedicine7

قناه شرح نظري كامل فيسيولوجي دكتور محمد فايز (اشترك الان حتي يصل لك كل جديد ان شاء الله)

https://youtube.com/@DrMohamedFayez?si=_XmfPrvmM5eEtwHI

I. Autonomic Nervous System (ANS)
■ is a set of pathways to and from the central nervous system (CNS) that innervates and regulates smooth muscle, cardiac muscle, and glands.
■ is distinct from the somatic nervous system, which innervates skeletal muscle.
■ has three divisions: sympathetic, parasympathetic, and enteric .
A. Organization of the ANS :
1. Synapses between neurons are made in the autonomic ganglia.
a. Parasympathetic ganglia are located in or near the effector organs.
b. Sympathetic ganglia are located in the paravertebral chain.
2. Preganglionic neurons have their cell bodies in the CNS and synapse in autonomic
ganglia.
■ Preganglionic neurons of the sympathetic nervous system originate in spinal cord seg-
ments T1–L3 or the thoracolumbar region.
■ Preganglionic neurons of the parasympathetic nervous system originate in the nuclei of
cranial nerves and in spinal cord segments S2–S4 or the craniosacral region.
3. Postganglionic neurons of both divisions have their cell bodies in the autonomic ganglia
and synapse on effector organs (e.g., heart, blood vessels, sweat glands).
4. Adrenal medulla is a specialized ganglion of the sympathetic nervous system.
■ Preganglionic fibers synapse directly on chromaffin cells in the adrenal medulla.
■ The chromaffin cells secrete epinephrine (80%) and norepinephrine (20%) into the cir-
culation .
■ Pheochromocytoma is a tumor of the adrenal medulla that secretes excessive amounts
of catecholamines and is associated with increased excretion of 3-methoxy-4-hydroxy-
mandelic acid (VMA).

B. Neurotransmitters of the ANS
■ Adrenergic neurons release norepinephrine as the neurotransmitter.
■ Cholinergic neurons, whether in the sympathetic or parasympathetic nervous system,
release acetylcholine (ACh) as the neurotransmitter.
■ Nonadrenergic, noncholinergic neurons include some postganglionic parasympathetic neurons of the gastrointestinal tract, which release substance P, vasoactive intestinal peptide
(VIP), or nitric oxide (NO).

👉Organization of the autonomic nervous system. ACh = acetylcholine; CNS = central nervous system.

✓ Receptor types in the ANS
1. Adrenergic receptors (adrenoreceptors)
a. a1 Receptors
■ are located on vascular smooth muscle of the skin and splanchnic regions, the gastrointestinal (GI) and bladder sphincters, and the radial muscle of the iris.
■ produce excitation (e.g., contraction or constriction).
■ are equally sensitive to norepinephrine and epinephrine. However, only norepi-
nephrine released from adrenergic neurons is present in high enough concentrations to activate α1
receptors.
■ Mechanism of action: G
q protein, stimulation of phospholipase C and increase in
inositol 1,4,5-triphosphate (IP3
) and intracellular [Ca2+
].
b. a2 Receptors
■ are located on sympathetic postganglionic nerve terminals (autoreceptors), plate-
lets, fat cells, and the walls of the GI tract (heteroreceptors).
■ often produce inhibition (e.g., relaxation or dilation).
■ Mechanism of action: Gi
protein, inhibition of adenylate cyclase and decrease in cyclic
adenosine monophosphate (cAMP).
c. b1 Receptors
■ are located in the sinoatrial (SA) node, atrioventricular (AV) node, and ventricular
muscle of the heart.
■ produce excitation (e.g., increased heart rate, increased conduction velocity,
increased contractility).
■ are sensitive to both norepinephrine and epinephrine, and are more sensitive than the α1 receptors.
■ Mechanism of action: Gs protein, stimulation of adenylate cyclase and increase in cAMP.
d. b2 Receptors
■ are located on vascular smooth muscle of skeletal muscle, bronchial smooth muscle,
and in the walls of the GI tract and bladder.
■ produce relaxation (e.g., dilation of vascular smooth muscle, dilation of bronchioles, relaxation of the bladder wall).
■ are more sensitive to epinephrine than to norepinephrine.
■ are more sensitive to epinephrine than the α1
receptors.
■ Mechanism of action: same as for β1 receptors.

Cholinergic receptors (cholinoreceptors)
a. Nicotinic receptors
■ are located in the autonomic ganglia (NN) of the sympathetic and parasympathetic
nervous systems, at the neuromuscular junction (NM), and in the adrenal medulla (NN).
The receptors at these locations are similar, but not identical.
■ are activated by ACh or nicotine.
■ produce excitation.
■ are blocked by ganglionic blockers (e.g., hexamethonium) in the autonomic ganglia,
but not at the neuromuscular junction.
■ Mechanism of action: ACh binds to α subunits of the nicotinic ACh receptor. The nicotinic ACh receptors are also ion channels for Na+ and K+
.
b. Muscarinic receptors
■ are located in the heart (M2), smooth muscle (M3), and glands (M3).
■ are inhibitory in the heart (e.g., decreased heart rate, decreased conduction velocity
in AV node).
■ are excitatory in smooth muscle and glands (e.g., increased GI motility, increased secretion).
■ are activated by ACh and muscarine.
■ are blocked by atropine.
■ Mechanism of action:
(1) Heart SA node: Gi protein, inhibition of adenylate cyclase, which leads to opening of K+ channels, slowing of the rate of spontaneous Phase 4 depolarization, and decreased heart rate.
(2) Smooth muscle and glands:
Gq protein, stimulation of phospholipase C, and increase in IP3 and intracellular [Ca2+].

🧠 Autonomic centers—brain stem and hypothalamus
1. Medulla
■ Vasomotor center
■ Respiratory center
■ Swallowing, coughing, and vomiting centers
2. Pons
■ Pneumotaxic center
3. Midbrain
■ Micturition center
4. Hypothalamus
■ Temperature regulation center
■ Thirst and food intake regulatory centers