AUTONOMIC NERVUS SYSTEM (ANS) Zahreni Hamzah Rahardyan Parnaadji Lab. Fisiologi – Bag Biomedik FKG Univ. Jember
AUTONOMIC NERVUS SYSTEM (ANS)
Zahreni HamzahRahardyan ParnaadjiLab. Fisiologi – Bag Biomedik FKG Univ. Jember
05/02/23 Free Template from www.brainybetty.com 2
How is the organization of the autonomic nervous
system (ANS) different from that of the somatic nervous
system (SNS)?
05/02/23 Free Template from www.brainybetty.com 3
Autonomic Nervous System (ANS)
• Operates without conscious instruction• Coordinates systems functions:
– cardiovascular– respiratory– digestive– urinary– reproductive
• Sistem ini merupakan sistem saraf eferen (motorik) yang mempersarafi organ-organ dalam seperti otot-otot polos, otot jantung, dan berbagai kelenjar.
• Sistem ini juga melakukan fungsi kontrol, semisal: kontrol tekanan darah, sekresi gastrointestinal,pengosongan kandung kemih, proses berkeringat, suhu tubuh, dan beberapafungsi lain.
• Karakteristik utama SSO:• kemampuan mempengaruhi yang sangat
cepat (misal: dalam beberapa detik denyut jantung dapat meningkat, perubahan tekanan darah, berkeringat).
• Keterlibatan dengan SSP: Medulla spinalis bertanggung jawab untuk persarafan otonom yang memengaruhi sistem kardiovaskular dan respirasi
• Hipotalamus berfungsi :Mengintegrasikanpersarafan otonom, somatik, dan hormonal (endokrin) dan emosi serta tingkah laku Misal: seseorang yang marah meningkatkan denyut jantung,tekanan darah, dan laju respirasi.
05/02/23 Free Template from www.brainybetty.com 6
ANS in the Nervous System
• Refleks visceral, sama seperti refleks somatik lainnya, terdiri atas komponen reseptor, integrasi, dan efektor.
Pembeda refleks visceral dengan refleks somatik:Informasi reseptor refleks visceral diterima secara bawah-sadar (subconscious). Misal: Pembuluh darah melebar (kulit yang kemerahan).Pupil mata melebar.
• PERJALANAN SSO DIMULAI DARI PERSARAFAN SSP:
• Neuron (orde pertama) berada di SSP (sisi lateral medullaspinalis dan di batang otak) > preganglionic fiber.
• Serabut ini bersinaps dengan badan sel neuron orde kedua yang terletak di dalam ganglion.
• Serabut pascaganglion menangkap sinyal dari serabut preganglion melalui neurotransmiter yang dilepaskan oleh serabut preganglion.
• (Ganglion: kumpulan badan sel yang terletak di luar SSP).
• Akson neuron orde kedua (postganglionic fiber) menuju organ yang akan diinervasi.
• Organ efektor menerima impuls melalui pelepasan neurotransmiter oleh serabut pascaganglion.
05/02/23 Free Template from www.brainybetty.com 9
Comparison of Somatic and Autonomic Nervous Systems
05/02/23 Free Template from www.brainybetty.com 10
Organization Similarities of SNS and ANS
• Are efferent divisions • Carry motor commands:
– SNS controls skeletal muscles– ANS controls visceral effectors
• Motor neurons synapse on visceral motor neurons in autonomic ganglia
• Ganglionic neurons control visceral effectors
05/02/23 Free Template from www.brainybetty.com 11
Organization Similarities of SNS and ANS
05/02/23 Free Template from www.brainybetty.com 12
Neurotransmitters and Receptors
• Acetylcholine (ACh) and norepinephrine (NE) are the two major neurotransmitters of the ANS
• ACh is released by all preganglionic axons and all parasympathetic postganglionic axons
• Cholinergic fibers – ACh-releasing fibers • Adrenergic fibers – sympathetic postganglionic
axons that release NE • Neurotransmitter effects can be excitatory or
inhibitory depending upon the receptor type
• Serabut preganglion parasimpatis melepaskan neurotransmitter asetilkolin (ACh) yang ditangkap oleh reseptor kolinergik nikotinik badan sel pascaganglion.
• Efek dari penangkapan ACh oleh reseptor nikotinik menyebabkan pembukaan kanal ion nonspesifik, menyebabkan influx terutama ion Na+
05/02/23 Free Template from www.brainybetty.com 13
Pelepasan Neurotransmitter
• Setelah itu, serabut pascaganglion parasimpatis juga menghasilan asetilkolin yang ditangkap oleh reseptor kolinergik muskarinik yang terdapat di semua organ efektor parasimpatis.
• Penempelan Ach dapat menginhibisi atau mengeksitasi organ efektor.
05/02/23 Free Template from www.brainybetty.com 14
• Serabut preganglion simpatis melepaskan neurotransmitter ACh yang ditangkap oleh reseptor nikotinik yang berada di badan sel neuronpascaganglion.
• Serabut pascaganglion melepaskan noradrenalin (atau norepinefrin) dan ditangkap oleh reseptor adrenergik.
05/02/23 Free Template from www.brainybetty.com 15
Pelepasan Neurotransmitter
05/02/23 Free Template from www.brainybetty.com 16
Differences between SANS and PANS
05/02/23 Free Template from www.brainybetty.com 17
What are the divisions and functions of the ANS?
05/02/23 Free Template from www.brainybetty.com 18
• Sympathetic Division :– “Kicks in” only during exertion, stress, or
emergency• Parasympathetic Division :
– Controls during resting conditions
• 2 divisions may work independently:– some structures innervated by only 1 division
• 2 divisions may work together:– each controlling one stage of a complex
process
• Divisi parasimpatis cenderung mengatur organ efektor dalam keadaan rest-and-digest, yakni ketika tubuh berada dalam keadaan tenang,relaks, kondisi yang tidak mengancam, atau dalam keadaan “pembersihan dan pemulihan tubuh” ( general housekeeping).
05/02/23 Free Template from www.brainybetty.com 19
05/02/23 Free Template from www.brainybetty.com 20
05/02/23 Free Template from www.brainybetty.com 21
05/02/23 Free Template from www.brainybetty.com 22
Parasympathetic Division OutflowCranial Outflow
Cranial Nerve Ganglion Effector Organ(s)
Occulomotor (III) Hypothalamic Control
Ciliary Eye
Facial (VII) PterygopalatinSubmandibular
Salivary, nasal, and lacrimal glands
Glossopharyngeal (IX)
Otic Parotid salivary glands
Vagus (X) Located within the walls of target organs
Heart, lungs, and most visceral organs
Sacral Outflow
S2-S4 Located within the walls of the target organs
Large intestine, urinary bladder, ureters, and reproductive organs
05/02/23 Free Template from www.brainybetty.com 23
05/02/23 Free Template from www.brainybetty.com 24
Visceral Reflexes
What are the mechanisms of neurotransmitter
release in the sympathetic division?
05/02/23 Free Template from www.brainybetty.com 26
SANS
05/02/23 Free Template from www.brainybetty.com 27
Sympathetic Receptors• Sympathetic Receptors
– Alpha receptors– Beta receptors
• Norepinephrine stimulates alpha receptors to greater degree than beta receptors
• Epinephrine stimulates both classes of receptors.
• Sympathetic postganglionic Fibers– Mostly adrenergic (release NE)– A few cholinergic (release ACh)
05/02/23 Free Template from www.brainybetty.com 28
Alpha (α) Receptors (activated by enzymes on inside of cell membrane)
Reseptor α-1• More common type of
alpha receptor• Releases intracellular
calcium ions from reserves in endoplasmic reticulum
• Has excitatory effect on target cell
Reseptor α-2• Lowers cAMP levels
in cytoplasm• Has inhibitory effect
on the cell• Helps coordinate
sympathetic and parasympathetic activities
05/02/23 Free Template from www.brainybetty.com 29
Beta () Receptors• Affect membranes in many organs (skeletal muscles,
lungs, heart, and liver)• Trigger metabolic changes in target cell• Changes occur indirectly• Each is a G protein • Stimulation increases intracellular cAMP levels• Beta-1 (1) - Increases metabolic activity• Beta-2 (2)
– Causes inhibition– Triggers relaxation of smooth muscles along respiratory tract
• Beta-3 (3)– Is found in adipose tissue– Leads to lipolysis, the breakdown of triglycerides in adipocytes– Releases fatty acids into circulation
05/02/23 Free Template from www.brainybetty.com 30
Adrenal Medulla
• Preganglionic fibers entering adrenal gland proceed to center (adrenal medulla)
• Modified sympathetic ganglion• Preganglionic fibers synapse on
neuroendocrine cells• Specialized neurons secrete hormones
into bloodstream
05/02/23 Free Template from www.brainybetty.com 31
7 Responses to Increased Sympathetic Activity
1. Heightened mental alertness2. Increased metabolic rate3. Reduced digestive and urinary functions4. Energy reserves activated5. Increased respiratory rate and
respiratory passageways dilate6. Increased heart rate and blood pressure7. Sweat glands activated
What are the structures and functions of the
parasympathetic division of the autonomic nervous
system?
05/02/23 Free Template from www.brainybetty.com 33
05/02/23 Free Template from www.brainybetty.com 34
Parasympathetic Division
• Preganglionic fibers originate in brain stem and sacral segments of spinal cord
• Synapse in ganglia close to (or within) target organs
• Preganglionic fibers are long• Postganglionic fibers are short
05/02/23 Free Template from www.brainybetty.com 35
Parasympathetic Activation
• Centers on relaxation, food processing, and energy absorption
• Localized effects, last a few seconds at most
05/02/23 Free Template from www.brainybetty.com 36
Parasympathetic Receptors• Action of Nicotinic Receptors
– Exposure to ACh causes excitation of ganglionic neuron or muscle fiber
– Open chemically gated channels in postsynaptic membrane
• Action of Muscarinic Receptors– Can be excitatory or inhibitory– Effects are longer lasting than nicotinic
receptors
05/02/23 Free Template from www.brainybetty.com 37
10 Effects of Parasympathetic Activation
1. Constriction of pupils:– restricts light entering eyes
2. Secretion by digestive glands:– exocrine and endocrine
3. Secretion of hormones4. Changes in blood flow and glandular activity:
– associated with sexual arousal
5. Increases smooth muscle activity:– along digestive tract
05/02/23 Free Template from www.brainybetty.com 38
10 Effects of Parasympathetic Activation
6. Defecation:– stimulation and coordination
7. Contraction of urinary bladder:– during urination
8. Constriction of respiratory passageways9. Reduction in heart rate:
– and force of contraction10.Sexual arousal:
– stimulation of sexual glands
05/02/23 Free Template from www.brainybetty.com 39
Parasympathetic division• The parasympathetic division release ACh• Body wall and skeletal muscles are not
innervated by parasympathetic division• Both NE and ACh needed to regulate
visceral functions
05/02/23 Free Template from www.brainybetty.com 40
Sympathetic and Parasympathetic Responses
Structure Sympathetic Stimulation Parasympathetic Stimulation
Iris (eye muscle)
Pupil dilation Pupil constriction
Salivary Glands
Saliva production reduced
Saliva production increased
Heart Heart rate and force increased
Heart rate and force decreased
Lung Bronchial muscle relaxed Bronchial muscle contracted
Stomach Peristalsis reduced Gastric juice secreted; motility increased
Kidney Decreased urine secretion
Increased urine secretion
Bladder Wall relaxedSphincter closed
Wall contractedSphincter relaxed
See in the next subject