NEUROANATOMI dan FISIOLOGI OTAK PERTEMUAN KE 2 ABDUL

NEUROANATOMI dan FISIOLOGI OTAK PERTEMUAN KE - 2 ABDUL CHALIK MEIDIAN & JERRY MARATIS FAKULTAS FISIOTERAPI

KEMAMPUAN AKHIR YANG DIHARAPKAN • Mahasiswa mampu memahami konsep dasar keilmuan bidang Neurosains dalam A. Penerapannya teori bidang fisioterapi B. Implementasinya praktik kasus penyakit bid. Fisioterapi C. Aplikasi pemecahan masalah penyakit pasien bidang Ft.

Gangguan Gerak dan fungsi • Gangguan gerak dan fungsi pada kasus neurologi ini dapat digolongkan sebagai sesuatu yang unik, karena alat gerak tubuh itu sendiri, dimana gerakan itu terjadi, seperti otot, tendon dan tulang tempat perlekatannya serta sendi, berada dalam keadaan yang normal. • Kelainan pd sistem saraf yaitu pengontrol dan lintasan impuls gerak.

Proses Gerak Secara umum Suatu gerakan terjadi dengan proses sbb: (1) Ide (2) Perencanaan motorik (3) Pengambilan keputusan (4) Programming proses (5) Perintah untuk gerakan (6) Eksekusi gerakan.

Susunan Saraf pada Tubuh Manusia • SUSUNAN SARAF • Susunan saraf pusat (SSP) – Otak – Medulla Spinalis • Susunan saraf tepi (SST) – Saraf kranial : 12 ps – Saraf spinal : 31 ps

Sistem Saraf Pusat

Perjalanan Impuls Sensorik & Motorik • Sensorik Tepi: Receptor serabut saraf sensorik perifer ganglion pre spinale PHC Sensorik Pusat: PHC tr spinothalamicus thalamus tr. thalamo corticalis cortex sensorik • Motorik • Upper Motor Neuron (UMN)/Motorik Pusat : Cortex motorik tr piramidal & extra piramidal (cortico spinalis) AHC. Lower Motor Neuron (LMN)/Motorik Tepi: AHC serabut saraf motorik perifer Otot • Koordinasi (Prosesing, Integrating, fungsi luhur) Fungsi ini hanya dimiliki oleh otak

Brain (Otak) • Berat otak 1200 – 1400 gram (2 % Berat Badan) • Terbagi atas – Otak besar (cerebrum) – Otak kecil (cerebellum) – Batang otak (brain stem, truncus cerebri) Hemisfer Otak terdiri 4 Lobus : 1. Lobus Frontalis : fungsi kognitif, persepsi, bahasa & bicara 2. Lobus Parietalis : fungsi memproses informasi sensorik 3. Lobus Temporalis : fungsi memproses pendengaran (auditory) 4. Lobus Occipitalis : fungsi memproses informasi penglihatan (visual)

Lapisan Otak • Selaput otak-spinal terdiri dari 3 lapis, yaitu: – Duramater – Arachnoid – Piamater • Dengan adanya selaput ini, maka terbentuk ruangan-ruangan – Subdural – Sub arachnoid (tempat mengalirnya cairan otak spinal) – Intra cerebral

Cerebrum (Otak Besar) • Cerebrum (otak besar) merupakan bagian otak manusia yang terbesar, paling berkembang dan memiliki fungsi luhur yang paling utama. • Otak besar terdiri dari substansia abu-abu (grey mater) setebal + 2 cm (cortex cerebri) yang berfungsi sebagai pusat intelektual, pusat bicara, emosi, integrasi sensorik dan motorik, kontrol gerak dan lain -lain.

• Sedangkan bagian dalam otak merupakan substansia putih (white matter) berisi “network” serabut-serabut saraf yang memungkinkan antar bagian otak saling berkomunikasi dan jaringan penyangga saraf yang berfungsi memberi bentuk otak.

Fungsi dari Bagian Otak

Sensory Homunculus

Motor Homunculus

Peran Cerebellum dan Brain stem • Cerebellum (otak kecil) merupakan bagian otak terbesar kedua, yang bertanggung jawab dalam mengatur keseimbangan, koordinasi dan berbagai kontrol motorik • Brain stem (batang otak) merupakan jalur terakhir dari otak yang menghubungkannya dengan medulla spinalis. Batang otak ini bertanggung jawab pada berbagai fungsi otonom seperti kontrol pernapasan, denyut jantung, tekanan darah, rangsangan dan perhatian

Medulla Spinalis • Medulla spinalis berawal dari dasar otak berjalan kebawah melalui segmen cervical dan thorakal dan berakhir setinggi antara L 1 -L 2 (conus medularis) ke bawah melanjutkan sebagai akar saraf menyerupai ekor kuda (cauda equina).

Neuro-Anatomy and General Function of The Brain 17

Gross anatomy of the brain • Neuroscience is a composite of several disciplines including : – neuroanatomy, – neurophysiology, – neuropathology, – neuropharmacology, – behavioral sciences, and – cell biology. – Etc. 18

Gross anatomy of the brain • An overview of the structural organization of the nervous system is helpful when beginning to study the neurosciences. • However, first it would be useful to define some basic terms that will be essential for understanding the anatomy of the nervous system. 19

Neuroanatomical Terms (1) • The spatial relationships of the brain and spinal cord usually are described by one or more of five paired terms: – medial–lateral – anterior–posterior – rostral–caudal – dorsal–ventral – superior–inferior 20

Neuroanatomical Terms (2) • Other terms commonly used in neuroanatomy are: – – – – – Ipsilateral–contralateral Commissure and decussation Neuron Nucleus Tract White and gray matter Glial cells Central and peripheral nervous systems Autonomic and somatic nervous systems 21

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Medial-Lateral • Medial means toward the median plane, and lateral means away from the median plane 23

Anterior–posterior • Above the midbrain, anterior means toward the front of the brain, and posterior means toward the back of the brain. • At and below the midbrain, anterior means toward the ventral surface of the body, and posterior means toward the dorsal surface of the body. 24

Rostral–caudal • Above the midbrain, rostral means toward the front of the brain, and caudal means toward the back of the brain. • At and below the midbrain, rostral means toward the cerebral cortex, and caudal means toward the sacral end (or bottom) of the spinal cord. 25

Dorsal–ventral • Rostral to the midbrain, dorsal refers to the top of the brain, and ventral refers to the bottom of the brain. • At the level of and caudal to the midbrain, dorsal means toward the posterior surface of the body, and ventral refers to the anterior surface of the body. 26

Superior–inferior • Both at positions above and below the midbrain, superior means toward the top of the cerebral cortex, and inferior means toward the bottom of the spinal cord. 27

Ipsilateral–contralateral • Ipsilateral means on the same side with reference to a specific point; contralateral means on the opposite side. 28

Commissure and decussation • Commissure is a group of nerve fibers connecting one side of the brain with the other. Decussation is the crossing over of these nerve fibers. 29

Neuron • A neuron is the anatomical and functional unit of the nervous system, which consists of a nerve cell body, dendrites (which receive signals from other neurons), and an axon (which transmits the signal to another neuron). 30

Nucleus • Nucleus refers to groups of neurons located in a specific region of the brain or spinal cord that generally have a similar appearance, receive information from similar sources, project their axons to similar targets, and share similar functions. 31

Tract • Many axons grouped together, which typically pass from a given nucleus to a common target region or to several regions, form a tract. 32

White and gray matter • When examining the brain or spinal cord with the unaided eye, one can distinguish white and gray tissue. • The region that appears white is called white matter, and the area that appears gray is called gray matter. • The appearance of the white matter is due to the large number of myelinated axons (largely lipid membranes that wrap around the axons) that are present in this region. • In contrast, the gray matter consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons. 33

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Glial cells • These nonneural cells form the interstitial tissue of the nervous system. • There are different types of glial cells, which include astrocytes, oligodendrocytes, microglia, and ependymal cells 36

Central and peripheral nervous systems • The central nervous system (CNS) includes the brain and spinal cord and is surrounded and protected by three connective tissue coverings called meninges. • Within the CNS are fluid-filled spaces called ventricles. • The bone of the skull and vertebral column surround the brain and spinal cord, respectively. • The peripheral nervous system (PNS) consists of spinal and cranial nerves that are present outside the CNS. 37

Autonomic and somatic nervous systems • These are functional subdivisions of the nervous system (in contrast to the anatomical classifications described earlier). Both of these divisions are present in the CNS and PNS. • The autonomic nervous system innervates smooth muscle and glands, whereas the somatic nervous system innervates mainly musculoskeletal structures and the sense organs of skin. 38

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Components of the Central Nervous System CNS The Brain Spinal Cord 48

Components of the Pheriperal Nervous System PNS Cranial Spinal 49

Cerebral Topography 1. Lateral Surface of the Brain 2. Medial Surface of the Brain 3. Inferior (Ventral) Surface of the Cerebral Cortex 4. Posterior Aspect of the Cerebral Cortex: Temporal and Occipital Lobes 50

Lateral Surface of the Brain (gambar 1. 2) • Four lobes of the cerebral cortex— – the frontal, – parietal, and – temporal lobes and – a portion of the occipital lobe 51

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Lateral Surface of the Brain • The lobes of the cerebral cortex integrate: – motor, – sensory, – autonomic, and – intellectual processes and – are organized along functional lines. 55

Lateral Surface of the Brain • The cortex consists of both : – cells – nerve fibers • The cellular components constitute the gray matter of cortex and lie superficial (i. e. , toward the surface of the cortex) to the nerve fibers. 56

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Medial Surface of the Brain (Gambar 1. 3) • The principal structures on the medial aspect of the brain can be seen clearly after the hemispheres are divided in the midsagittal plane. 61

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Inferior (Ventral) Surface of the Cerebral Cortex (Gambar 1. 4) • The medial aspect of the anterior part of the prefrontal cortex contains a region called the gyrus rectus. • Lateral to the gyrus rectus lies a structure called the olfactory bulb, a brain structure that appears as a primitive form of cortex consisting of neuronal cell bodies, axons, and synaptic connections. • The olfactory bulb receives information from the fi rst (olfactory) cranial nerve and gives rise to a pathway called the olfactory tract. 66

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Posterior Aspect of the Cerebral Cortex: Temporal and Occipital Lobes (Gambar 1. 4, 1. 5, 1. 6) • The occipitotemporal gyrus lies medial to the inferior temporal gyrus and is bound medially by the collateral sulcus. • The parahippocampal gyrus lies medial to the collateral sulcus. • There is a medial extension of the anterior end of the parahippocampal gyrus called the uncus. • The hippocampal formation and amygdala (described in the following discussion) are situated deep to the cortex of the parahippocampal gyrus 68 and uncus.

Forebrain Structures Visible in Horizontal and Frontal Sections of the Brain • • Ventricles Basal Ganglia Diencephalon Limbic Structures 69

Ventricles • As shown in horizontal and frontal sections of the brain cavities present within each hemisphere are called ventricles and contain cerebrospinal fluid ([CSF] 70

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Basal Ganglia • The basal ganglia play an important role in motor integration processes associated with the cerebral cortex. Damage to this region results in motor dysfunctions referred to as dyskinesias (i. e. , disorders of movement at rest). 72

Diencephalon • As mentioned previously, the diencephalon includes principally the thalamus, situated dorsally, and the hypothalamus, situated ventrally. The medial border of the diencephalon is the third ventricle, and the lateral border is the internal capsule. 73

Limbic Structures • Limbic structures serve important functions in the regulation of emotional behavior, short-term memory processes, and control of autonomic, other visceral, and hormonal functions usually associated with the hypothalamus. 74

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Topography of the Cerebellum and Brainstem • The cerebellum plays a vital role in the integration, regulation, and coordination of motor processes. Damage to this region can result in loss of balance, loss of coordinated movements, hypotonia, and errors in movement when attempting to produce a specific response. 79

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General Function of The brain 82

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Proses Gerak SECARA UMUM Suatu gerakan terjadi dengan proses sbb: (1) Ide (2) Perencanaan motorik (3) Pengambilan keputusan (4) Programming proses (5) Perintah untuk gerakan (6) Eksekusi gerakan. 90

Gangguan Gerak • Ganguan gerak dan fungsi pada kasus neurologi ini dapat digolongkan sebagai sesuatu yang unik, karena alat gerak tubuh itu sendiri dimana gerakan itu terjadi, seperti otot, tendon dan tulang tempat perlekatannya serta sendi berada dalam keadaan yang normal. • Kelainan pada sistem saraf yaitu pengontrol dan lintasan impuls gerak. 91

Reference 1. Siegel, A. Sapru, H, N. 2015. Essential Neuroscience. 3 rd. Philadelphia: Lippincott Williams & Wilkins 2. Kandel, E, R. Et. Al. 2013. Principles Of Neural Scoence. 5 th. New York: Mc. Graw-Hill Companies 92