Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Bagaimana jantung dapat memompa darah setinggi lebih dari 2 meter ke kepala Jerapah ?
Sistem sirkulasi
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Bagaimana tubuh mengakomodasi tekanan darah di kepala ketika Jerapah minum ?
• Perubahan tekanan dapat diakomodasi dengan kontraksi otot di leher Jerapah
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Fungsi dan struktur sistem sirkulasi
• Membawa O2 dan nutrient ke bagian tubuh
• Mengambil CO2 dan sampah metabolik dari tubuh
• Sehingga sistem sirkulasi harus punya kontak dengan sel-sel pada berbagai jaringan
Sel darah merahKapiler
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Molekul terdifusi antara sel-sel dan kapiler yang posisinya sangat berdekatan
Kapiler
Cairan INTERSTITIAL
Tissuecell
Proses difusi
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Sistem sirkulasi pada hewan bisa terbuka atau tertutup
• Sistem terbuka– Jantung tubuler memompa darah lewat saluran
terbuka ke ruang antar sel.
Pori-pori
Jantung tubuler
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Sistem tertutup
– Jantung memonmpa darah miskin 02 yang dibawa arteri ke insang, dari insang dihasilkan darah kaya 02 dibawa kebagian tubuh via kapiler.Darah miskin 02
dibawa vena ke jantung.
Arteri(Darah kaya O2-)
Arteriole
Kapiler
Venule
Vena
Atrium
VentrikelJantung
Arteri(Darah miskin O2)
Kapiler insang
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• Sistem sirkulasi ikan dan hewan darat Kapiler insang
Heart:
Ventricle (V)
Atrium (A)
Kapiler sistemik
Sirkuit paru-paru
A
Kapiler sistemik
Kapiler paru-paru
V
Kanan
Sirkuit Sistemik
A
V
Kiri
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RIGHT VENTRICLE
1
23
Capillariesof right lung
3
Capillariesof left lung
4
LEFT ATRIUM5
LEFT VENTRICLE
6
Aorta
7Capillaries ofHead and arms
8
Capillaries ofabdominal organsand legs
9
Superiorvena cava
10
Inferiorvena cava
11
RIGHT ATRIUM
Pulmonaryvein
Aorta
Pulmonaryvein
Pulmonaryartery
Pulmonaryartery
• Sistem sirkulasi manusia
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Diastole (rileks)– Darah masuk kedalam
jantung
Figure 23.6
Heart isrelaxed.AV valvesare open.
1 2
3
Atriacontract.
Ventriclescontract.Semilunarvalvesare open.
SYSTOLE
DIASTOLE
0.4 sec
0.1 sec
0.3 sec
• Systole (berdenyut)– Arteri berkontraksi dan darah
masuk ke ventrikel
– Kemudian ventrikel berkontraksi menyebarkan darah ke seluruh tubuh
– Mengapa darah tidak kembali ?
Jantung berdenyut dengan ritme
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Pulmonaryartery
Superiorvena cava
RIGHTATRIUM
Pulmonaryveins
Semilunarvalve
Atrioventricularvalve
Inferiorvena cava
Aorta
Pulmonaryartery
LEFTATRIUM
Pulmonaryveins
Semilunarvalve
Atrioventricularvalve
RIGHTVENTRICLE
LEFTVENTRICLE
• Jantung memiliki katup :– katup
semilunar (SV)
– katup atrioventricular (AV)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• SA node (pacemaker = pacu jantung) secara berkala menghasilkan sinyal listrik ke atrium sehingga berdenyut. SA node terdiri dari sel-sel yang secara independen (tidak tergantung sinyal saraf) tereksitasi secara berkala dan berkesinambungan.
• Sinyal berhenti sekitar 0.1 detik di AV node, kemudian membawa sinyal ke ventrikel sehingga berdenyut.
Jantung berdenyut => pacu jantung (alami)
Figure 23.7
Pacemaker(SA node)
1 2 3 4
Rightatrium
Rightventricle
AV nodeSpecializedmuscle fibers
ECG
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Serangan jantung• Serangan jantung diakibatkan karena
penyumbatan saluran arteri pada jantung (Jantung koroner)
Rightcoronaryartery
Aorta
Leftcoronaryartery
Blockage
Dead muscle tissue
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Jantung koroner• Biasanya disebabkan karena sistem metabolisme
lemak terganggu sehingga kadar kolesterol meningkat dalam darah.
• Kadar kolesterol yang tinggi dalam waktu tertentu dapat mengakibatkan penebalan pembuluh arteri koroner, akhirnya tersumbat dan berakibat jantung berhenti (serangan jantung)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Apa yang terjadi pada jerapah ? Darah harus dibawa dari kaki ke jantung yang tingginya bisa 3 meter, atau ketika jerapah sedang minum• Otot polos pada vena akan berkontraksi
dibantu gerakan otot lainnya
• Katup pada vena membantu darah mengalir tanpa kembali lagi
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Epithelium
Smoothmuscle
Connectivetissue
ARTERY
ARTERIOLE
CAPILLARY
Epithelium Basementmembrane
Epithelium
Smoothmuscle
Connectivetissue
Valve
VEIN
VENULE
• Vena memiliki katup sehingga darah tetap mengalir dan tidak kembali lagi
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Tekanan di arteri sangat kuat, tetapi di vena lemah
Figure 23.9A
Diastolicpressure
Systolicpressure
Relative sizes andnumbersof blood vessels
• Mengapa kecepatan di kapiler malah sangat rendah ?
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Di saluran vena kecepatan darah meningkat lagi, meskipun tekanan masih sangat rendah ?
– Kontraksi otot, setiap kali bergerak otot akan menekan vena menghasilkan tekanan dan memaksa aliran darah bergerak satu arah
Figure 23.9B
Direction ofblood flowin vein
Valve (closed)
Skeletal muscleValve (open)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Teknik mengukur tekanan darah
Tekanan darah dan penyakit darah tinggi/rendah
Figure 23.10
Blood pressure120 systolic80 diastolic(to be measured)
1 2 3 4
Rubber cuffinflated with air
Pressurein cuffbelow120
Pressurein cuffbelow 80
Artery
Pressurein cuffabove120
Soundsaudible instethoscope
Soundsstop
Arteryclosed
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Penyakit tekanan darah tinggi
• Darah tinggi bukanlah penyebab sakit, tetapi merupakan indikasi adanya kelainan fungsi tubuh lainnya.
• Kolesterol menyebabkan viskositas darah lebih tinggi, sehingga tekanan darah menjadi lebih tinggi. Ada sebab lain seperti kadar gula darah atau fungsi ginjal yang tidak normal.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Pengaturan aliran pada kapiler
• Dalam banyak kasus tekanan darah dan mutu darah bisa berbeda, demikian pula kebutuhan tiap organ berbeda setiap saat.
• Pada saat makan, organ pencernaan mendapat pasokan darah lebih banyak, bagaimana ini diatur ?
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Sinyal kebutuhan akan pasokan darah dibawa ke otot polos di organ-organ tertentu
Otot polos pada saluran darah ada di arteri dan vena, juga terdapat di pre-
capilary sphincter
1 Sphincters relaxed 2 Sphincters contracted
Precapillary sphincters Thoroughfarechannel
CapillariesArteriole Venule Arteriole Venule
Thoroughfarechannel
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 23.12B
Arterialend of
capillary
Tissue cells
Osmoticpressure
INTERSTITIALFLUID NET PRESSURE
OUT
Bloodpressure
Bloodpressure
Osmoticpressure Venous
end ofcapillary
NET PRESSUREIN
Tekanan darah mengatur keluar masuknya nutrisi
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Withdrawblood
Place in tube
PLASMA 55%
CONSTITUENT MAJOR FUNCTIONS
WaterSolvent forcarrying othersubstances
SaltsSodiumPotassiumCalciumMagnesiumChlorideBicarbonate
Plasma proteins
Osmotic balance,pH bufferingClottingImmunity
Albumin
FibrinogenImmunoglobins(antibodies)
Substances transported by bloodNutrients (e.g., glucose, fatty acids, vitamins)Waste products of metabolismRespiratory gases (O2 and CO2)Hormones
Centrifuge
CELLULAR ELEMENTS 45%
CELL TYPE NUMBER(per mm3 of blood)
FUNCTIONS
Erythrocytes(red blood cells) 5–6 million Transport of
oxygen (and carbon dioxide)
Leukocytes(white blood cells) 5,000–10,000
Defense andimmunity
Basophil
Eosinophil
Neutrophil
Lymphocyte
Monocyte
Platelets 250,000–400,000
Blood clotting
Sel darah
Osmotic balance,pH buffering, andregulation ofmembranepermeability
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Jika luka, platelet akan bereaksi sehingga terjadi penyumbatan akibataksi dari platelet
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 23.16A
Platelet releases chemicalsthat make nearby platelets sticky
Injury to lining of bloodvessel exposes connectivetissue; platelets adhere
1 2 3Platelet plug forms Fibrin clot trapsblood cells
Connectivetissue
Plateletplug
Clotting factors from:
Platelets
Damaged cells
Calcium andother factorsin blood plasma
Prothrombin Thrombin
Fibrinogen Fibrin
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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