Materi Lampiran RPP Sistem KOORDINASI Utk RSBI

Lampiran : RPP SISTEM KOORDINASI RSBI

ISTILAH PENTING IMPULS yaitu rangsangan atau pesan . Disampaikan melalui senyawa kimia dalam

tubuh yaitu asetilkolin. RESEPTOR yaitu struktur yang dapat

menerima impuls.Dapat berupa sel, jaringan atau organ, alat gerak, otot.

EFEKTOR yaitu struktur yang dapat menanggapi impuls. Dapat berupaa sel, jaringan atau organ, alat gerak, otot.

Neruon atau sel saraf yaitu merupakan sel yang terpanjang yang dimilki oleh tubuh manusia dan bertugas untuk menerima dan menghantarkan impuls ke tempat yang dituju.

Organel penyusun sel saraf/Neuron1. Dendrit merupakan penjuluran

pendek yang keluar dari badan sel. Berfungsi untuk menghantarkan impuls dari luar sel neuron ke dalam badan sel.

2. Badan sel merupakan bagian neuron yang banyak mengandung cairan sel (sitoplasma) dan terdapatnya nucleus (inti sel). Berfungsi sebagai penerima impuls dari dendrti dan menghantarkannya menuju axon dengan perantaraan sitoplasma.

3. Sitoplasma merupakan cairan pengisi badan sel. Berfungsi untuk mempercepat penyampaian/ penghantaran impuls dalam sel.

4. Nucleus merupakan bagian terpenting dari sel.benetuknya akan menyesuaikan bentuk sel. Berfungsi untuk mengatur seluruh kegiatan sel dan pembelahan sel.

5. Axon/neurit merupakan poenjukluran yang panjang yang keluar dari badan sel. Berfungsi untuk menerima impuls dari badan sel dan menghantarkannya ke percabangan axon.

6. Percabangan axon merupakan bagian dari axon yang bercabang-cabang. Berfungsi menerima impuls dari axon.

7. Selubung neurolema/neurilema merupakan selaput tipis yang berda paling luar dari axon. Berfungsi untuk melindungi axon serta memberikan nutrisi pada axon serta regenrasi pada selubung mielin.

8. Selubung myelin merupakan selaput tipis yang berhubungan langsung dengan axon dan terletak setelah selubung neurilema. Berfungsi untuk melindungi axon dan memberikan nutrisi pada axon.

9. Sel Schwann merupakan sel-sel yangterdapat di dalam selubung myelin. Berfungsi untuk memperbaiki sel axon yang rusak/regenerasi.

10. Nodus Ranvier merupakan celah diantara axonyang tidak tertutup oleh selubung neurilema. Berfungsi untuk mempercepat penyampaian impuls ke neuron.

Pembagian sel neuron a. Berdasarkan fungsinya

1. Saraf sensorik/aferen yaitu neuron yang berfungsi untuk menghantarkan impuls dari reseptor ke sistem saraf pusat (SSP).

2. Saraf motorik/eferen yaitu neuron yang berfungsi untuk menghantarkan impuls dari SSP ke efektor.

RPP Sistem Koordinasi – SMPN 1 Mejayan – IX – Agus Joko Sungkono – 11/12

3. Saraf asosiasi/interneuron yaitu neuron yang menghubungkan saraf sensorik dengan sarf motorik di dalam SSP.

b. Berdasarkan strukturnya1. Neuron unipolar yaitu neuron yang memiliki satu buah axon yang bercabang.2. Neuron bipolar yaitu neuron yang memiliki satu axon dan satu dendrite.3. Neuron multipolar yaitu neuron yang memiliki satu axon dan sejumlah dendrite.

Sinapsis Merupakan hubungan penyampaian impuls dari satu neuron ke neuron yang lain.

biasanya terjadi dari ujung percabangan axon dengan ujung dendrite neuron yang lain.

Celah antara satu neuron dengan neuron yang lain disebut dengan celah sinapsis. Di dalam celah sinapsis inilah terjadi loncatan-loncatan listrik yang bermuatan ion,baik ion positif dan ion negatif. Di dalam celah sinapsis ini juga terjadi pergantian antara impuls yang satu dengan yang lain, sehingga diperlukan enzim kolinetarase untuk menetralkan asetilkolin pembawa impuls yang ada. Dalam celah sinapsis juga terdapat penyampaian impuls dengan bantuan zat kimia berupa asetilkolin yang berperan sebagai pengirim (transmitter).


Muatan listrik dalam neuron Muatan listrik yang terjadi dalam satu axon akan memiliki muatan listrik yang

berbeda antara lapisan luar dan lapisan dalam axon. Polarisasi yaitu keadaan istirahat pada sel neuron yang memperlihatkan muatan

listrik positif dibagian luar dan muatan listrik negative di bagian dalam. Depolarisasi yaitu keadaan bekerjanya sel neuron yang memperlihatkan muatan

listrik positif di bagian dalam dan muatan listrik negative di bagian luar.

Gerakan berdasarkan tanggapan impuls1. Gerak biasa merupakan gerakan yang disadari dan impuls akan diolah oleh SSP

(otak dan medulla spinalis) terbeih dahulu sebelum terjadi gerakan.

Skema/bagan gerakan biasaImpuls reseptor neuron sensorik medulla spinalis otak Medulla spinalis interneuron neuron motorik Efektor gerakan

2. Gerak refleks merupakan gerakan yang tanpa disadari karena menanggapi impuls secara langsung. Sehingga sifat gerakan ini tidak diolah terlebih dahulu oleh otak. Jarak terpendek efektor dalam menanggapi impuls disebut dengan lengkung refleks.

Skema/bagan gerak refleksImpuls reseptor neuron sensorik medulla spinalis interneuron Neuron motorik efektor gerakan.

3. Macam gerakan refleks tergantung dari tanggapan efektor terhadap impuls yang ada. Bila tanggapan terhadap impuls melibatkan satu efektor saja, maka disebut dengan refleks tunggal. Jika tanggapan terhadap impuls melibatkan lebih dari 1 efektor maka disebut dengan refleks kompleks.

SSP (Sistem Saraf Pusat)


1. OtakDiselimuti oleh selaput otak yang disebut selaput meninges. Selaput meninges terdiri dari 3 lapisan :a. Lapisan durameter yaitu lapisan yang terdapat di paling luar dari otak dan

bersifat tidak kenyal. Lapisan ini melekat langsung dengan tulang tengkorak. Berfungsi untuk melindungi jaringan-jaringan yang halus dari otak dan medula spinalis.

b. Lapisan araknoid yaitu lapisan yang berada dibagian tengah dan terdiri dari lapisan yang berbentuk jaring laba-laba. Ruangan dalam lapisan ini disebut dengan ruang subaraknoid dan memiliki cairan yang disebut cairan serebrospinal. Lapisan ini berfungsi untuk melindungi otak dan medulla spinalis dari guncangan.

c. Lapisan piameter yaitu lapisan yang terdapat paling dalam dari otak dan melekat langsung pada otak. Lapisan ini banyak memiliki pembuluh darah. Berfungsi untuk melindungi otak secara langsung.

Otak dibagi menjadi beberapa bagian :a. Cerebrum

Merupakan bagian otak yang memenuhi sebagian besar dari otak kita yaitu 7/8 dari otak.

Mempunyai 2 bagian belahan otak yaitu otak besar belahan kiri yang berfungsi mengatur kegaiatan organ tubuh bagian kanan. Kemudian otak besar belahan kanan yang berfungsi mengatur kegiatan organ tubuh bagian kiri.

Bagian kortex cerebrum berwarna kelabu yang banyak mengandung badan sel saraf. Sedangkan bagian medulla berwarna putih yang bayak mengandung dendrit dan neurit. Bagian kortex dibagi menjadi 3 area yaitu area sensorik yang menerjemahkan impuls menjadi sensasi. Kedua adalah area motorik yang


berfungsi mengendalikan koordinasi kegiatan otot rangka. Ketiga adalah area asosiasi yang berkaitan dengan ingatan, memori, kecedasan, nalar/logika, kemauan.

Mempunyai 4 macam lobus yaitu : Lobus frontal berfungsi sebagai pusat penciuman, indera peraba. Lobus temporal berungsi sebagai pusat pendengaran Lobus oksipetal berfungsi sebagai pusat pengliihatan. Lobus parietal berfungsi sebagai pusat ingatan, kecerdasan, memori,

kemauan, nalar, sikap.

b. Mesencephalon Merupakan bagian otak yang terletak di depan cerebellum dan jembatan

varol. Berfungsi sebagai pusat pengaturanan refleks mata, refleks penyempitan

pupil mata dan pendengaran.

c. Diencephalaon Merupakan bagia otak yang terletak dibagian atas dari batang otak dan di

depan mesencephalon. Terdiri dari talamus yang berfungsi untuk stasiun pemancar bagi impuls

yang sampai di otak dan medulla spinalis. Bagian yang kedua adalah hipotalamus yang berfungsi sebagai pusat

pengaturan suhu tubuh, selera makan dan keseimbangan cairan tubuh, rasalapar, sexualitas, watak, emosi.

d. Cerebellum Merupakan bagian otak yang terletak di bagian belakang otak besar. Berfungsi

sebagai pusat pengaturan koordinasi gerakan yang disadari dan keseimbangan tubuh serta posisi tubuh.

Terdapat 2 bagian belahan yaitu belahan cerebellum bagian kiri dan belahan cerebellum bagian kanan yang dihubungkan dengan jembatan varoli yang berfungsi untuk menghantarkan impuls dari otot-otot belahan kiri dan kanan.

2. Medulaa. Medulla oblongata

Disebut juga dengan sumsum lanjutan atau penghubung atau batang otak. Terletak langsung setelah otak dan menghubungkana dengan medulla

spinalis, di depan cerebellum. Susunan kortexmya terdiri dari neeurit dan dendrite dengan warna putih

dan bagian medulla terdiri dari bdan sel saraf dengan warna kelabu.

Berfungsi sebagai pusat pengaturan ritme respirasi, denyut jantung, penyempitan dan pelebaran pembuluh darah, tekanan darah, gerak alat pencernaan, menelan, batuk, bersin,sendawa.

b. Medulla spinalis Disebut denga sumsum tulang belakang dan

terletak di dalam ruas-ruas tulang belakang yaitu ruas tulang leher sampaia dengan tulang pinggang yang kedua.

Berfungsi sebagai pusat gerak refleks dan menghantarkan impuls dari organ ke otak dan dari otak ke organ tubuh.

SST (Susunan Saraf Tepi/Perifer)Merupakan system saraf yang menghubungkan semua bagian tubuh dengan system saraf pusat.


1. Sistem saraf sadar/somatikMerupakan system saraf yang kerjanya berlangsung secara sadar/diperintah oleh otak. Bedakan menjadi dua yaitu :

a. Sistem saraf pada otak Merupakan sistem saraf yang berpusat pada otak dan dibedakan menjadi 12

pasang saraf yaitu :

Endocrine System

IntroductionA. The endocrine system is made up of the cells, tissues, and organs that secrete

hormones into body fluids.B. The body has two kinds of glands;

Exocrine (secretes products into ducts) endocrine (secrete products into body fluids to affect target cells).

General Characteristics of the Endocrine System A. The endocrine system’s function is to communicate with cells using chemicals

called hormones.B. Endocrine glands and their hormones regulate a number of metabolic processes

within cells, and the whole body. C. Their actions are precise, they only affect specific target cells.D. Endocrine glands include the

1. pituitary gland, 2. thyroid gland, 3. parathyroid glands, 4. adrenal glands, 5. pancreas, and other hormone-secreting glands and tissues.


Otak Depan

Telencephalon

Otak Tengah

Otak Belakang

Diencephalon

Mesencephalon

Metencephalon

Myelencephalon

Cerebrum (Otak Besar)

Diencephalon (thalamus, hipothalamus, epithalamus)

Otak Tengah (merupakan bagan dari batang otak)

Pons (bagian dari batang otak) , cerebellum

Medulla oblongata (bagian dari batang otak)

Otak TengahOtak Belakang

Otak Depana. Embrio saat

berumur 1 bulan

(b) Embrio saat berumur 5 minggu(c) Otak manusia dewasa

MesencephalonMetencephalon

Myelencephalon

Syaraf Spinal

Diencephalon

Telencephalon

CerebralDiencephalon:

HipothalamusThalamusKelenjar Pineal

(bagian dari epithalamus)Batang Otak:

Otak TengahPons

Medullaoblongata

Cerebellum (Otak Kecil)Syaraf Spinal

Hormone Action A. Hormones are can be divided into three groups on the basis of chemical structure:

amino acid derivatives (Epinephrine, Norepinephrine, thyroid hormones, melatonin), peptide hormones ( ADH, Oxytocin, GH, Prolactin), and lipid derivatives (steroids). • Alter cellular operations by changing the identies, activities, or quantities of

import enzymes and structural proteins in various target cells. • they can influence target cells even if they are present only in minute

concentrations.

B. Nonsteroid Hormones 1. Receptors in target cell membranes2. The hormone-receptor complex (as first messenger) triggers a cascade

biological activity.3. The hormone-receptor complex generally activates a G protein, which then

activates the enzyme adenylate cyclase that is bound to the inner cell membrane.

4. This enzyme removes two phosphates from ATP to produce cyclic AMP (the second messenger), which in turn activates protein enzymes that activate proteins.

5. These activated proteins induce changes in the cell.6. Not all nonsteroid hormones use cAMP; others use diacylglycerol (DAG) or

inositol triphosphate.

C. Prostaglandins 1. Prostaglandins are locally-produced lipids that affect the organ in which they are

produced.2. Prostaglandins produce a variety of effects: some relax smooth muscle, others

contract smooth muscle, some stimulate secretion of other hormones, and others influence blood pressure and inflammation.

Control of Hormonal SecretionsA. Hormone levels are very precisely regulated. B. Control Mechanisms


1. Release of hormones from the hypothalamus controls secretions of the anterior pituitary.

2. The nervous system influences certain endocrine glands directly.3. Other glands respond directly to changes in the internal fluid composition.

C. Negative Feedback Systems 1. Commonly, negative feedback mechanisms control hormonal releases.2. In a negative feedback system, a gland is sensitive to the concentration of the

substance it regulates or which regulates it.3. When the concentration of the regulated substance reaches a certain level (high

or low), it inhibits the gland from secreting more hormone until the concentration returns to normal.

Pituitary Gland “Master Gland”A. The pituitary gland is attached to the base of the brain • has an anterior lobe (anterior pituitary) & • a posterior lobe (posterior pituitary).

B. The brain controls the activity of the pituitary gland.1. Releasing hormones from the hypothalamus control the secretions of the

Anterior Pituitary.a. The releasing hormones are carried in the bloodstream directly to the

Anterior Pituitary by hypophyseal portal veins.2. The Posterior Pituitary releases hormones into the bloodstream in response

to nerve impulses from the hypothalamus. C. Anterior Pituitary Hormones

1. The anterior pituitary consists mostly of epithelial tissue arranged around blood vessels and enclosed in a capsule of collagenous connective tissue.

I. Growth hormone (GH) II. Prolactin (PRL) III. Thyroid-stimulating hormone (TSH)


IV. Adrenocorticotropic hormone (ACTH) V. Follicle-stimulating hormone (FSH) and VI. Luteinizing hormone (LH)

2. Growth hormone (GH) stimulates body cells to grow and reproduce; it also speeds the rate at which cells use carbohydrates and fats.a. Growth hormone-releasing hormone from the hypothalamus increases the

amount of GH released, GH release-inhibiting hormone inhibits its release.b. Nutritional status affects the release of GH

Acromegaly- excess GH causes an enlargement of hands and feet, facial features

3. Prolactin (PRL) promotes milk production following the birth of an infant.a. The effect of PRL in males is less-well understood, although it may cause a

deficiency of male sex hormones. Prolactinoma- menstral changes, infertility, in men impotence, loss of

sexual drive4. Thyroid-stimulating hormone (TSH) controls the secretion of hormones from the

thyroid gland.a. Thyrotropin-releasing hormone (TRH) from the hypothalamus regulates the

release of TSH.b. As blood concentrations of thyroid hormones increases, secretions of TRH

and TSH decrease. Hypothyroidism (Hashimoto’s disease, Goiter) and Hyperthyroidism

(Graves’ disease)5. Adrenocorticotropic hormone (ACTH) controls the secretion of hormones from

the adrenal cortex.a. It is regulated by corticotropin-releasing hormone from the hypothalamus,

and stress can also increase its release. Adrenal gland diseases- glucocorticoids (blood sugar levels and

metabolism of proteins and fats), Mineralocorticoids (body’s electrolyte level), and Androgens (sex hormones)

6. Follicle-stimulating hormone (FSH) and luteinizing horm o ne (LH) are gonadotropins affecting the male and female sex organs. Infertility

D. Posterior Pituitary Hormones1. The posterior lobe consists of nerve fibers and neuroglial cells that support

nerve fibers arising in the hypothalamus.2. Neurons in the hypothalamus produce antidiuretic hormone and oxytocin, which

are stored in the posterior pituitary.3. Antidiuretic hormone (ADH) produces its effect by causing the kidneys to

conserve water.a. The hypothalamus regulates the secretion of ADH based on the amount of

water in body fluids. Diabetes Insipidus- insufficient ADH loss of water balance

4. Oxytocin plays a role in childbirth by contracting muscles in the uterine wall, and in milk-letdown by forcing milk into ducts from the milk glands.a. Stretching of the uterus in the latter stages of pregnancy stimulates release

of oxytocin.b. Suckling of an infant at the breast stimulates release of oxytocin after

childbirth. Inducing Labor- synthetic oxytocin


Thyroid Gland A. The thyroid gland is located below the larynx and consists of two broad lobes

connected by an isthmus.B. Structure of the Gland

1. The thyroid consists of secretory parts called follicles filled with hormone-storing colloid.

C. Thyroid Hormones1. The follicular cells produce two iodine-containing hormones, thyroxine (T4)

(tetraiodothyronine) and triiodothyronine (T3), that together regulate energy metabolism.a. These two hormones increase the rate at which cells release energy from

carbohydrates, enhance protein synthesis, and stimulate the breakdown and mobilization of lipids.

b. These hormones are essential for normal growth and development.c. The hypothalamus and pituitary gland control release of thyroid hormones.

2. Extrafollicular cells of the thyroid secrete calcitonin, which lowers blood levels of calcium and phosphate ions when they are too high.a. Calcitonin increases the rate at which calcium is stored in bones and

excreted in the urine.b. Calcitonin secretion is regulated by negative feedback involving blood

concentrations of calcium.

Parathyroid Glands


A. The four, tiny parathyroids are located on the posterior of the thyroid.

B. Structure of the Glands 1. Parathyroid glands consist of tightly packed

secretory cells covered by a thin capsule of connective tissue.

C. Parathyroid Hormone1. Parathyroid hormone (PTH) increases blood

calcium ion concentration and decreases phosphate ion concentration.

2. PTH stimulates bone resorption by osteoclasts, which releases calcium into the blood.

3. PTH also influences the kidneys to conserve calcium and causes increased absorption of calcium in the intestines

4. A negative feedback mechanism involving blood calcium levels regulates release of PTH.

D. Calcitonin and PTH exert opposite effects in regulating calcium ion levels in the blood. • Adrenals• Pancreas• Pineal Gland• Thymus• Reproductive• Digestive glands• Stress and Health

Adrenal Glands A. The adrenal glands sit atop the kidneys enclosed in a layer of fat.B. Structure of the Glands

1. The pyramid-shaped glands consist of an inner adrenal medulla and an outer adrenal cortex.

2. The adrenal medulla is made up of modified postganglionic neurons that are connected to the sympathetic nervous system.

3. The adrenal cortex makes up most of the adrenal glands and consists of epithelial cells in three layers - an outer, middle, and an inner zone.

C. Hormones of the Adrenal Medulla 1. The adrenal medulla secretes epinephrine and

norepinephrine into the blood stream.2. The effects of these hormones resemble those

of the sympathetic division neurotransmitters of the same name, except that they last up to 10 times longer when they are secreted as hormones.

3. The are used in times of stress and for “fight or flight.”

4. Release of medullary hormones is regulated by nervous impulses from the central nervous system.

D. Hormones of the Adrenal Cortex 1. The cells of the adrenal cortex produce over 30 different steroids, some of which

are vital to survival, the most important of which are aldosterone (mineralocorticoid), cortisol (Glucocorticoid), and the sex hormones (Androgens).

2. Aldosteronea. Aldosterone, a mineralocorticoid, causes the kidneys to conserve sodium ions

and thus water, and to excrete potassium ions.b. Aldosterone is secreted in response to decreasing blood volume and blood


pressure as a result of changes in the kidney.3. Cortisol

a. Cortisol, a glucocorticoid, influences the metabolism of glucose, protein, and fat in response to conditions that stress the body and require a greater supply of energy in the bloodstream. Cushing’s Syndrome- excess cortisol, longer healing time, face becomes

puffy, fatigue, high blood pressure, hyperglycemicb. A negative feedback mechanism involving CRH from the hypothalamus

and ACTH from the anterior pituitary controls the release of cortisol.c. Stress, injury, or disease can also trigger increased release of cortisol.

4. Adrenal Sex Hormonesa. Sex hormones, produced in the inner zone, are mostly of the male type, but

can be converted to female hormones in the skin, liver, and adipose tissues.b. These hormones supplement those released by the gonads and may

stimulate early development of reproductive organs.

PancreasA. The pancreas secretes hormones as an

endocrine gland, and digestive juices to the digestive tract as an exocrine gland.

B. Structure of the Gland1. The pancreas is an elongated organ

posterior to the stomach.2. Its endocrine portions are the islets of

Langerhans that include two cell types--alpha cells that secrete glucagon, and beta cells that secrete insulin.

C. Hormones of the Islets of Langerhans1. Glucagon increases the blood levels of

glucose by stimulating the breakdown of glycogen and the conversion of noncarbohydrates into glucose.a. The release of glucagon is controlled by a negative feedback system

involving low blood glucose levels.2. Insulin decreases the blood levels of glucose by stimulating the liver to form

glycogen, increasing protein synthesis, and stimulating adipose cells to store fat.a. The release of insulin is controlled by a negative feedback system

involving high blood glucose levels.3. Insulin and glucagon coordinate to maintain a relatively stable blood glucose

concentration.

Other Endocrine Glands A. Pineal Gland

1. The pineal gland, near the upper portion of the thalamus, secretes melatonin, which is involved in the regulation of circadian rhythms of the body.

B. Thymus Gland1. The thymus gland, lying between the lungs under the sternum, secretes

thymosins that affect production and differentiation of T lymphocytes that are important in immunity.

C. Reproductive Glands 1. The ovaries produce estrogen and progesterone.2. The placenta produces estrogen, progesterone, and a gonadotropin.3. The testes produce testosterone.

D. Digestive Glands 1. The digestive glands secrete hormones associated with the processes of

digestion.E. Other Hormone Producing Organs

1. The heart secretes atrial natriuretic peptide affecting sodium and the kidneys secrete erythropoietin for blood cell production.

Stress and Health


A. Factors that serve as stressors to the body produce stress and threaten homeostasis.

B. Types of Stress 1. Stress may be physical, psychological, or some combination of the two2. Physical stress threatens the survival of tissues, such as extreme cold,

prolonged exercise, or infections.3. Psychological stress results from real or perceived dangers, and includes

feelings of anger, depression, fear, and grief; sometimes even pleasant stimuli cause stress.

C. Response to Stress1. Responses to stress are designed to maintain homeostasis.2. The hypothalamus controls the general stress syndrome, which involves

increased sympathetic activity and increased secretion of cortisol, glucagon, growth hormone, and antidiuretic hormone.

Special Senses ‐ Smell and Taste

Chemical Senses: Taste and Smell Both senses use chemoreceptors Stimulated by chemicals in solution Taste has four types of receptors Smell can differentiate a large range of chemicals Both senses complement each other and respond to many of the same stimuli

Olfaction—The Sense of Smell Olfactory receptors are in the roof of the nasal cavity Neurons with long cilia Chemicals must be dissolved in mucus for detection Impulses are transmitted via the olfactory nerve Interpretation of smells is made in the cortex

The Sense of Taste Taste buds house the receptor organs Location of taste buds Most are on the tongue Soft palate Cheeks The tongue is covered with projections called papillae Filiform papillae—sharp with no taste buds Fungifiorm papillae—rounded with taste buds Circumvallate papillae—large papillae with taste buds Taste buds are found on the sides of papillae Gustatory cells are the receptors Have gustatory hairs (long microvilli) Hairs are stimulated by chemicals dissolved in saliva


Taste Buds Taste Sensations Sweet receptors (sug-ars) Saccharine Some amino acids Sour receptors Acids Bitter receptors Alkaloids Salty receptors Metal ions Umami Elicited by the amino

acid glutamate and re-lated compounds

The Eye and Vision 70% of all sensory receptors are in the eyes Each eye has over a million nerve fibers Protection for the eye Most of the eye is enclosed in a bony or-bit A cushion of fat surrounds most of the eye

Accessory Structures of the Eye Eyelids and eyelashes Conjunctiva Lacrimal apparatus Extrinsic eye muscles Accessory Structures of the Eye Eyelids and eyelashes Tarsal glands lubricate the eye Ciliary glands are located between the

eyelashes Conjunctiva Membrane that lines the eyelids Connects to the surface of the eye Secretes mucus to lubricate the eye Lacrimal apparatus Lacrimal gland—produces lacrimal fluid Lacrimal canals—drain lacrimal fluid

from eyes Lacrimal sac—provides passage of

lacrimal fluid towards nasal cavity Nasolacrimal duct—empties lacrimal

fluid into the nasal cavity

Accessory Structures of the Eye Function of the lacrimal apparatus Protects, moistens, and lubricates the eye Empties into the nasal cavity Properties of lacrimal fluid Dilute salt solution (tears) Contains antibodies and lysozyme Extrinsic eye muscles Six muscles attach to the outer surface of the eye Produce eye movements


Structure of the Eye Layers forming the wall of the eye-ball Fibrous layer Outside layer Vascular layer Middle layer Sensory layer Inside layer

Structure of the Eye: The Fibrous Layer

Sclera White connective tissue layer Seen anteriorly as the “white of the eye” Cornea Transparent, central anterior portion Allows for light to pass through Repairs itself easily The only human tissue that can be trans-

planted without fear of rejection

Structure of the Eye: Vascular Layer Choroid is a blood‐rich nutritive layer in the

posterior of the eye Pigment prevents light from scattering Modified anteriorly into two structures Ciliary body—smooth muscle attached to

lens Iris—regulates amount of light entering eye Pigmented layer that gives eye color Pupil—rounded opening in the iris


Structure of the Eye: Sensory Layer Retina Fovea centralis – highest concentration of photoreceptors Optic disc (blind spot) is where the optic nerve leaves the eyeball Cannot see images focused on the optic disc

Structure of the Eye: Sensory Layer Retina contains two layers Outer pigmented layer Inner neural layer Contains receptor cells (photoreceptors) Signals pass from photoreceptors via a two‐neuron chain Signals leave the retina toward the brain through the optic nerve

Structure of the Eye: Sensory Layer Discs contain rhodopsin A purple pigment consisting of the protein opsin covalently bound to a yellow photo-sensitive pigment called retinal (derived from Vit. A) Exposure to light activates rhodopsin Rhodopsin is split by light into retinal and opsin, eventually resulting in an action po-tential Light adaptation is caused by a reduction of rhodopsin


Dark adaptation is caused by rhodopsin production

Lens Biconvex crystal‐like structure Held in place by a suspensory ligament attached to the ciliary body Cataracts result when the lens becomes hard and opaque with age Vision becomes hazy and distorted Eventually causes blindness in affected eye

Lens Aqueous and Vitreous Humor Aqueous humor Watery fluid found between lens and cornea Similar to blood plasma Helps maintain intraocular pressure Provides nutrients for the lens and cornea Reabsorbed into venous blood through the scleral venous sinus, or canal of Schlemm Vitreous humor Gel‐like substance posterior to the lens Prevents the eye from collapsing Helps maintain intraocular pressure

Pathway of Light Through the Eye Light must be focused to a point on the retina for optimal vision The eye is set for distance vision (over 20 feet away) Accommodation—the lens must change shape to focus on closer objects (less than 20 feet away)


Sensory Layer Rods Most are found towards the edges of the retina Allow dim light vision and peripheral vision All perception is in gray tones Cones Allow for detailed color vision Densest in the center of the retina Fovea centralis—area of the retina with only

cones Cone sensitivity Three types of cones Different cones are sensitive to different wave-

lengths Color blindness is the result of the lack of

one cone type

Pathway of Light Through the Eye Image formed on the retina is a real image Real images are Reversed from left to right Upside down Smaller than the object

A Closer Look Emmetropia—eye focuses images correctly on the retina Myopia (nearsighted) Distant objects appear blurry Light from those objects fails to reach the retina and are focused in front of it Results from an eyeball that is too long Hyperopia (farsighted) Near objects are blurry while distant objects are clear Distant objects are focused behind the retina Results from an eyeball that is too short or from a “lazy lens” Astigmatism Images are blurry Results from light focusing as lines, not points, on the retina due to unequal curva-

tures of the cornea or lens

Visual Disorders Homeostatic Imbalances of the Eyes Night blindness—inhibited rod function that hinders the ability to see at night Color blindness—genetic conditions that result in the inability to see certain colors Due to the lack of one type of cone (partial color blindness) Cataracts—when lens becomes hard and opaque, our vision becomes hazy and dis-torted Glaucoma—can cause blindness due to increasing pressure within the eye


Hearing and Balance

The Ear Houses two senses Hearing Equilibrium (balance) Receptors are mechanoreceptors Different organs house receptors for

each sense

Anatomy of the Ear The ear is divided into three areas External (outer) ear Middle ear (tympanic cavity) Inner ear (bony labyrinth)

The External Ear Involved in hearing only Structures of the external ear Auricle External acoustic meatus (auditory canal) Narrow chamber in the temporal bone Lined with skin and ceruminous (wax) glands Ends at the tympanic membrane

The Middle Ear (Tympanic Cavity) Air‐filled cavity within the temporal bone Oval window and round window connect

to the inner ear Three bones (ossicles) span the cavity Malleus (hammer) Incus (anvil) Stapes (stirrip) Two tubes are associated with the inner

ear Mastoid air cells The auditory tube connecting the middle

ear with the throat Allows for equalizing pressure during

yawning or swallowing This tube is otherwise collapsed


Inner Ear or Bony Labyrinth Includes sense organs for hearing and bal-

ance Filled with perilymph A maze of bony chambers within the tem-

poral bone Cochlea Vestibule Semicircular canals

Anatomy of the Ear Organs of Equilibrium Equilibrium receptors of the inner ear are

called the vestibular apparatus Vestibular apparatus has two functional parts Static equilibrium Dynamic equilibrium

Static Equilibrium Maculae—receptors in the vestibule Report on the position of the head Hair cells are embedded in the otolithic membrane Otoliths (tiny stones) float in a gel around the hair cells Movements cause otoliths to bend the hair cells

Dynamic Equilibrium Crista ampullaris—receptors in the semicircular canals Tuft of hair cells Cupula (gelatinous cap) covers the hair cells Action of angular head movements The cupula stimulates the hair cells An impulse is sent via the vestibular nerve to the cerebellum Action of angular head movements The cupula stimulates the hair cells An impulse is sent via the vestibular nerve to the cerebellum


Organs of Hearing Organ of Corti Located within the cochlea Receptors = hair cells on the basilar membrane Gel‐like tectorial membrane is capable of bend-

ing hair cells Cochlear nerve attached to hair cells

transmits nerve impulses to auditory cortex on temporal lobe

Mechanism of Hearing Vibrations from sound waves move tectorial

membrane Hair cells are bent by the membrane An action potential starts in the cochlear nerve Continued stimulation can lead to

adaptation


Materi Lampiran RPP Sistem KOORDINASI Utk RSBI

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