Human Anatomy and Physiology PDF

인체해부생리학 2 (Human Anatomy and Physiology) 연세대학교 의과대학 생화학분자생물학 교실 고 은 진...

인체해부생리학 2 (Human Anatomy and Physiology) 연세대학교 의과대학 생화학분자생물학 교실 고 은 진 [email protected], 02-2228-1677 ©2019 McGraw-Hill Education.  참고문헌 유인물 (Handout) 제15판 인체해부생리학 (라이프사이언스) Hole's Human Anatomy and Physiology 16th Marieb, Elaine, and Katja Hoehn. Human Anatomy and Physiology 유인물에 학생이 강의 내용을 필기하는 방식으로 진행 성적산출: 중간 30%, 기말 30%, 레포트 30% 출석 10% ©2019 McGraw-Hill Education.  1. Introduction, Nervous system-1 2. Nervous system-2 3. Nervous system-3 4. Endocrine system 5. Blood 6. Cardiovascular system-1 7. Cardiovascular system-2 8. Midterm examination 9. Lymphatic system 10. Digestive system 11. Respiratory system 12. Urinary system 13. water, electrolyte, and acid-base balance 14. Reproductive system 15. Final examination ©2019 McGraw-Hill Education.  Figure 10.1 The Nervous System Interprets and Responds to Information Nervous system: Detects changes, makes decisions, stimulates muscles and glands to respond, and maintains homeostasis Neural tissue contains 2 cell types: Neurons: 신경세포 React to changes. Send nerve impulses. Communication. Non-neuron Neuroglia: 신경아교세포, 신경교세포 :신경세포 숫자의 10배 이상 Surround and support neurons. Nourish neurons. Send & receive messages. Help maintain blood-brain barrier. ©2019 McGraw-Hill Education. © McGraw-Hill Education/Al Telser  Divisions of the Nervous System 뇌와 척수 Central Nervous System (CNS): 중추신경계 Brain. Spinal cord. Track: a bundle of axons in the CNS Peripheral Nervous System (PNS): 말초신경계 체성 신경 Connects CNS to other body parts Cranial nerves (뇌신경) carry impulses to and from the brain 자율 신경 Spinal nerves (척수신경) carry impulses to and from the spinal cord Nerve: a bundle of axons in the PNS ©2019 McGraw-Hill Education.  General Functions of the Nervous System Sensory Function: (PNS) Nervous system receives information. Sensory receptors gather information by detecting changes. Information is carried to the CNS. Integrative Function: Nervous system coordinates sensory information to create sensations, memory, thoughts. Nervous system makes decisions on body’s response to sensory information. Motor Function: (PNS) Decisions are acted upon Impulses are carried to effectors (muscles or glands) Divisions of motor portion of PNS: Somatic Nervous System (체성신경계): transmits voluntary instructions to skeletal muscles Autonomic Nervous System (자율신경계): transmits involuntary instructions from the CNS to smooth muscles, cardiac muscle, and glands ©2019 McGraw-Hill Education.  PNS에서 나옴 PNS로 들어감 자율신경계 ✓ Keeps the CNS constantly informed of events going on body inside and outside the body autonomic=a law unto itself ✓ Somatic sensory fibers convey impulses from the skin, skeletal muscles and joints (soma=body) 체성신경계 부교감 신경 ✓ Visceral sensory fibers transmit impulses from the visceral organs (organs within the ventral body cavity) 교감 신경 ©2019 McGraw-Hill Education.  Nervous tissue ✓ Supporting cells called neuroglia (or glial cells), small cells that surround and wrap the more delicate neurons: support and maintain neurons; six types of neuroglia=four in the CNS and two in the PNS ✓ Neurons, nerve cells that are excitable (respond to stimuli by changing their membrane potential) and transmit electrical signals; the structural units of the nervous system ©2019 McGraw-Hill Education.  Neurons Neurons vary in size and shape. They may differ in length and size of their axons and dendrites. Neurons share certain features: 미토콘드리아, 소포체 등 Cell body (soma, 세포체): contains nucleus, cytoplasm, organelles, neurofilaments, chromatophilic substance (Nissl bodies; mainly composed of rough ER). nuclei (pl.) 신경핵: clusters of cell bodies in the CNS (nucleus) ganglia (pl.) 신경절: clusters of cell bodies in the PNS (ganglion) Dendrites (수상돌기): branched receptive surfaces; a neuron may have many. 끝부분엔 리보솜 없음 Axon (축삭): transmits impulses and releases neurotransmitters to another neuron or 미토콘드리아는 있음 effector (another neuron, a muscle cell or a gland cell); a neuron may have only 1 axon. mitochondria, neurofibril, microtubules Action potential Axon hillock. 세포체와 축삭 연결 부위 (triggering region) Collaterals (곁가지). Axon terminal. Synaptic knob. Axon terminal 끝에 위치 ©2019 McGraw-Hill Education.  Figure 10.4 Myelination of Axons 슈반 세포 Schwann Cells: PNS neuroglia that encase axons in a sheath Schwann cells wrap tightly around axon in layers composed of myelin, a lipoprotein mixture Coating is called the Myelin Sheath Nodes of Ranvier (신경섬유마디): Gaps in myelin sheath between Schwann cells Neurilemma Neurolemma ©2019 McGraw-Hill Education. © Biophoto Associates/Science Source  Figure 10.5 Myelination of Axons Not all axons are myelinated. Myelinated axons in the PNS have a series of Schwann cells lined up along the axon, each having a wrapped coating of myelin insulating the axon. 신경전달속도가 unmyelinated axon보다 빠름. White matter를 구성함. (in the CNS: oligodendrocytes; in the brain and spinal cord, myelinated axons do not have neurilemmae) Unmyelinated axons are encased by Schwann cell cytoplasm, but there is no wrapped coating of myelin surrounding the axons. Gray matter를 구성함. ©2019 McGraw-Hill Education. © Dennis Emery  Figure 10.6 Classification of Cells of the Nervous System Classification of neurons by structure: Bipolar neurons: Two processes. Essentially all bipolar neurons are sensory neurons Eyes, ears, nose. 한 방향으로만 감! Unipolar neurons: One process. Cell bodies are in ganglia. 가장 흔한 형태 Most unipolar neurons are sensory neurons that conduct impulses along afferent pathways to the CNS for interpretation. ©2019 McGraw-Hill Education.  Multipolar neurons: 99% of neurons. Many processes (cell body로부터 여러돌기). Most neurons of C N S. 1. Most multipolar neurons are interneurons that conduct impulses within the CNS, integrating sensory input or motor output. May be one of a chain of CNS neurons, or a single neuron connecting sensory and motor neurons. 2. Some multipolar neurons are motor neurons that conduct impulses along the efferent pathways from the CNS to an effector (muscle/gland). ©2019 McGraw-Hill Education.  Figure 10.7 Classification of Neurons Classification of neurons by function: Sensory Neurons: 감각 신경 Afferent neurons. Carry impulse to CNS. Most are unipolar. Some are bipolar. Interneurons: Association neurons. Link neurons. Multipolar. Located in CNS. Motor Neurons: 운동 신경 Multipolar, efferent. Carry impulses away from CNS. Carry impulses to effectors. ©2019 McGraw-Hill Education.  Neuroglia in the CNS 4개의 종류 해당 표 참조 CNS Myelin sheath ©2019 McGraw-Hill Education.  Neuroglia of the CNS Astrocytes: Connect neurons to blood vessels; exchange nutrients and growth factors. Form scar tissue: 뇌조직 손상에 반응하여 흉터조직을 만들어 CNS에서 공간을 채워주고 틈을 닫아준다. Aid metabolism of certain substances. Regulate ion concentrations, such as K +. Part of Blood Brain Barrier (BBB;혈액과 CNS사이의 물질 이동을 제한). Oligodendrocytes: Myelinate CNS axons; also provide structural support. Microglia: Phagocytic cell; also provides structural support. Ependyma or ependymal cells: Line central canal of spinal cord (척수중심과)& ventricles of brain(뇌실), cover choroid plexuses (맥락얼기). Help regulate composition of cerebrospinal fluid (뇌척수액). Cuboidal or columnar cells; ciliated (cilia:섬모). ©2019 McGraw-Hill Education.  Figure 10.4 Neuroglia of the PNS Schwann Cells (neurolemmocytes): Produce myelin sheath found on some peripheral axons. Vital to regeneration of damaged peripheral nerve fibers Speed up speed of nerve impulse transmission. Satellite Cells: PNS cell body cluster Support clusters of neuron cell bodies (ganglia). Functions like astrocytes in the CNS ©2019 McGraw-Hill Education. © Biophoto Associates/Science Source  Neuroglia and Axonal Regeneration Mature neurons do not divide. If cell body is injured, the neuron usually dies. Neuron Regeneration in the PNS: If a peripheral axon is injured, it may regenerate. Axon separated from cell body and its myelin sheath will degenerate. Schwann cells and neurilemma remain. Remaining Schwann cells provide guiding sheath for growing axon. (neuroglial cells secrets growth hormones) If growing axon establishes former connection, function will return; if not, function may be lost. Neuron Regeneration in the CNS: CNS axons lack neurilemma to act as guiding sheath. Oligodendrocytes do not proliferate after injury. Regeneration is unlikely. ©2019 McGraw-Hill Education.  Figure 10.10 Neuron Regeneration in the PNS 시간이 지남에 따라 cell body쪽의 axon은 재생되고, 남아있는 Schwann세포들에 의해 관 형태로 자라난다. ©2019 McGraw-Hill Education.  Figure 10.11 The Synapse Neurons communicate with each other at synapses. A synapse is a site at which a neuron transmits a nerve impulse to another neuron. Presynaptic neuron sends impulse. Postsynaptic neuron receives impulse. Synaptic cleft separates the 2 neurons. ©2019 McGraw-Hill Education.  읽어보기 Figure 10.12 Synaptic Transmission Synaptic Transmission: One-way transfer of information. Impulse travels down axon of presynaptic neuron to axon terminal. When impulse reaches synaptic knob, causes influx of Ca+ ions. This leads to release of neurotransmitters from synaptic vesicles by exocytosis. Neurotransmitter will exert either excitatory (흥분) or inhibitory (억제) effect on postsynaptic neuron. 전기 신호 = 채널들에 의한 전위 변화 ©2019 McGraw-Hill Education. © Don W. Fawcett/Science Source  Cell Membrane Potential 막전위 A cell membrane is usually electrically charged, or polarized, so that the inside of the membrane is negatively charged with respect to the outside of the membrane. This is a result of unequal distribution of ions on the inside and the outside of the membrane. 밖은 나트륨, 안은 칼륨이 많음 Important in conduction of impulses in neurons and muscle fibers. Resting membrane potential RMP Stimulation Threshold membrane potential Action potential (nerve impulse, axon): depolarization → repolarization Neurotransmitter release Postsynaptic neuron stimulation ©2019 McGraw-Hill Education.  Resting Membrane Potential (RMP) Generating a resting membrane potential depends on (1) differences in K+ and Na+ concentrations inside and outside cells, and (2) differences in permeability of the plasma membrane to these ions. ©2019 McGraw-Hill Education.  확산 확산 ©2019 McGraw-Hill Education.  Resting Potential Resting Membrane Potential (RMP): Resting neuron is one that is not being stimulated. + + Na and K ions follow rules of diffusion, and move from area of high concentration to area of low concentration. 70 mV potential difference from inside to outside of cell. Membrane of the neuron is a polarized membrane, with more K + ions inside the cell, more Na+ ions outside the cell, and more negatively charged ions & proteins inside. The resting cell membrane is much more permeable to K + ions than Na+ ions. Inside of cell is negative relative to the outside of the cell. RMP for a typical neuron = −70 mV, due to unequal charge distribution. If resting potential changes, Na+ /K + pump restores it. ©2019 McGraw-Hill Education.  Figure 10.14 Resting Potential 1 (a) In a hypothetical neuron before the membrane potential is established, potassium ions diffuse out of the cell faster than sodium ions diffuse in. A net loss of positive charge from the cell results. ©2019 McGraw-Hill Education.  Figure 10.14 Resting Potential 2 (b) The net loss of positive charges from inside the cell leaves the inside of the cell membrane slightly negative compared to the outside, which is slightly positive. This difference, called an electrical "potential difference," measures -70 millivolts (mV) in a typical neuron, and is called the resting membrane potential. ©2019 McGraw-Hill Education.  Figure 10.14 Resting Potential 3 (c) The membrane potential, negative on the inside of the membrane, aids sodium diffusion into the cell, and opposes potassium diffusion out of the cell. As a result, slightly more sodium ions enter the cell than potassium ions leave. However, the sodium/potassium pump balances these movements, maintaining the concentrations of these ions and the resting membrane potential. ©2019 McGraw-Hill Education.  Local Potential Changes (국소전위의 변화) Neurons are excitable cells. 국소적인 전위차 Detect stimuli, and respond by changing their resting potential. Common response is the opening of a gated ion channel. ------------------------------------------------------------------------------------------------------------------------------ If membrane potential becomes more negative, the membrane is hyperpolarized. If membrane potential becomes less negative (more positive), the membrane is depolarized. ------------------------------------------------------------------------------------------------------------------------------ Local potential changes: the greater the stimulus intensity, the greater the potential change If degree of depolarization reaches threshold potential of −55 mV, an action potential results. If degree of depolarization does not reach threshold potential, an action potential will not occur. ©2019 McGraw-Hill Education.  N-methyl D-aspartate (NMDA) receptors: ligand-gated cation channels activated by an excitatory neurotransmitter, glutamate. These receptors are located mostly at excitatory synapses, and thereby, participate in excitatory neurotransmission in the central nervous system. Glutamate: Most abundant excitatory neurotransmitter in the CNS Sodium이 들어옴 Image Credit: Emre Terim/Shutterstock.com ©2019 McGraw-Hill Education.  GABA receptors: a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid (GABA), the chief inhibitory compound in the mature vertebrate central nervous system. -70mV => 세포 내막이 세포 외막보다 minus charge ©2019 McGraw-Hill Education.  Local Potential Changes (국소전위의 변화) -70 => -55mV로 탈분극되어야 반응 시작 Neurons are excitable cells. Detect stimuli, and respond by changing their resting potential. Common response is the opening of a gated ion channel. ------------------------------------------------------------------------------------------------------------------------------ If membrane potential becomes more negative, the membrane is hyperpolarized. GABA If membrane potential becomes less negative (more positive), the membrane is depolarized. NMDA ------------------------------------------------------------------------------------------------------------------------------ Local potential changes: the greater the stimulus intensity, the greater the potential change If degree of depolarization reaches threshold potential of −55 mV, an action potential results. If degree of depolarization does not reach threshold potential, an action potential will not occur. ©2019 McGraw-Hill Education.  Hyperpolarization ©2019 McGraw-Hill Education.  Image Credit: Emre Terim/Shutterstock.com ©2019 McGraw-Hill Education.  Local Potential Changes (국소전위의 변화) Neurons are excitable cells. Detect stimuli, and respond by changing their resting potential. Common response is the opening of a gated ion channel. ------------------------------------------------------------------------------------------------------------------------------ If membrane potential becomes more negative, the membrane is hyperpolarized. If membrane potential becomes less negative (more positive), the membrane is depolarized. ------------------------------------------------------------------------------------------------------------------------------ Local potential changes: the greater the stimulus intensity, the greater the potential change If degree of depolarization reaches threshold potential (역치전위)of −55 mV, an action potential results. All or none response If degree of depolarization does not reach threshold potential, an action potential (활동전위) will not occur. Nerve impulse, only at axon ©2019 McGraw-Hill Education.  Figure 10.15 Local Potential Changes Recording of an Action Potential: Summation 특정 voltage에 반응하는 sodium channel 열림 Temporal Spatial 더 이상 올라갈 수 없음 세포 내 voltage gated potassium channel 열림 Potassium 빠져나가게 됨 EPSP, IPSP > 평형 이룸 Potassium channel의 permeability가 좋기 때문에 과분극이 발생 ©2019 McGraw-Hill Education.  복습 Figure 10.16 Local Potential Changes (a) If sodium or potassium channels open, more of that particular ion will cross the cell membrane, altering the resting membrane potential. The illustration depicts the effect of sodium channels opening in response to a neurotransmitter. As sodium ions enter the cell, the membrane potential becomes more positive (or less negative), changing from -70 millivolts to -62 millivolts in this example. This change in a positive direction is called depolarization. Here the depolarization is subthreshold, and does not generate an action potential. (b) If sufficient sodium ions enter the cell and the membrane potential depolarizes to threshold (here -55 millivolts), another type of sodium channel opens. These channel are found along the axon, especially near the origin in an area called the "trigger zone." Opening of these channels triggers the action potential. ©2019 McGraw-Hill Education.  복습 Synaptic Transmission Synaptic transmission: Transmission of a nerve impulse from one neuron to another. Released neurotransmitters cross the synaptic cleft and react with specific receptors in the membrane of postsynaptic neuron. Effects of neurotransmitters vary; some open ion channels and others close ion channels. Chemically gated ion channels respond to neurotransmitters. Local potentials resulting from changes in chemically gated ion channels are called synaptic potentials. Excitatory neurotransmitters increase permeability to Na+ ions, bring membrane closer to threshold; increase likelihood of generating impulses. Inhibitory neurotransmitters move membrane farther from threshold, decrease likelihood of generating impulses. ©2019 McGraw-Hill Education.  복습 Figure 10.20 Summation of EPSPs and IPSPs EPSPs and IPSPs are added together in a process called summation. Net excitatory effect leads to great probability of an action potential. Net inhibitory effect does not generate action potentials. Summation of all inputs usually occurs at the trigger zone (axon hillock). ©2019 McGraw-Hill Education.  Action Potentials (활동전위) 세포체에서 축삭돌기로 갈 때 좁아지는 부분 Axon hillock / Initial segment / Trigger zone at first part of axon contains many voltage-gated sodium channels. Voltage-gated Na+ channels remain closed at resting potential. Voltage-gated Na+ channels open when threshold is reached. + As Na ions diffuse into the cell, the membrane depolarizes until it reaches +30 mV (beginning the action potential). 탈분극 + + Na channels close and K channels open. + K ions diffuse out down their concentration gradient, and the membrane Repolarizes. 재분극 As membrane potential then drops below -70mV, the membrane is temporarily hyperpolarized. K + channels then close. Active transport re-establishes the resting potential of -70mV as Na+ and K + + + concentrations are restored by the Na /K Pump. Concentration gradients are maintained while the neuron is at rest. ©2019 McGraw-Hill Education.  -70 => -55mV Depolarizing: + Repolarizing: - Hyperpolarizing: more - Axon hillock => abundance of voltage gated sodium gate => therefore the voltage can surge up to 30mV Impulse gets transmitted along this direction Neurotransmitters allow pre-synaptic signals to travel to post-synaptic neurons Calcium facilitates neurotransmitters’ fusion Voltage gated potassium channel also exists => lowers the voltage from 30 to -80mV by letting potassium out of the cell => hyperpolarization ©2019 McGraw-Hill Education.  Figure 10.17 Ion Movements During Action Potentials At rest, the membrane is polarized (RMP = −70). Threshold stimulus reached (−55 mV). Sodium channels open and membrane depolarizes (toward 0). Potassium leaves cytoplasm and membrane repolarizes (+30 mV). Brief period of hyperpolarization (−90). Return to RMP (−70 mV). ©2019 McGraw-Hill Education.  복습 Figure 10.18 Action Potentials (활동전위) Action potentials are propagated down the length of the axon as nerve impulses : An action potential is often referred to as an “all-or-none” response, because either it is achieved or it is not. That is, if the neuron does not make it to —55 mV, nothing much happens, but once it does, there is no turning back. This is when the neuron takes action, or “fires,” beginning the process of sending the signal along the axon. ©2019 McGraw-Hill Education.  복습 Table 10.3 Events Leading to Impulse Conduction Table 10.3 Events Leading to Impulse Conduction 1. Nerve cell membrane maintains resting potential by diffusion of Na+ and K+ down their concentration gradients as the cell pumps them up the gradients. 2. Neurons receive stimulation, causing local potentials, which may sum to reach threshold. 3. Sodium channels in the trigger zone of the axon open. 4. Sodium ions diffuse inward, depolarizing the membrane. 5. Potassium channels in the membrane open. 6. Potassium ions diffuse outward, repolarizing the membrane. 7. The resulting action potential causes an electric current that stimulates adjacent portions of the membrane. 8. The action potential propagates along the length of the axon. ©2019 McGraw-Hill Education. 불응기 (Refractory period): limits number of action potentials generated per sec Absolute refractory period: 절대 불응기 (첫 번째 AP가 끝나기 전에 두 번째 AP 생성 불가) => time when threshold stimulus can not generate another action potential => voltage gated Na+ channels are briefly unresponsive Relative refractory period: 상대적 불응기 (과분극 상태에서 RMP를 다시 회복할 때까지의 기간, 절대 불응기 직후) => theme when only high-intensity stimulus can generate another action potential => repolarization is not complete and membrane is re-establishing resting potential  Refractory Period (불응기) During an impulse, the portion of the axon actively conducting the action potential is not able to respond to another threshold stimulus of normal strength. This is called the Refractory Period: Refractory period limits number of action potentials generated per second 활동전위중의 axon은 다른 역치자극에는 반응하지 않는다. 따라서 axon이 생성할 수 있는 초당 활동전위의 수는 제한적이다. (AP/1 mSec) Absolute Refractory Period: 절대 불응기: 첫번째 AP가 끝나기 전에 두번째 AP는 발생하지 않음. Time when threshold stimulus cannot generate another action potential Voltage-gated Na+ channels are briefly unresponsive. Relative Refractory Period: 상대적 불응기: Hyperpolarized → RMP 을 다시 확립할 때까지의 기간 (절대불응기 후 바로 이어지는 기간) Time when only high-intensity stimulus can generate another action potential. Repolarization is not complete, and membrane is re-establishing resting potential. ©2019 McGraw-Hill Education.  Impulse Conduction The speed of impulse conduction varies with myelination. Myelin is rich in lipids, and prevents water and water-soluble substances (such as ions) from crossing membrane; acts as electrical insulator (절연체). Ions can cross membrane only through gaps in myelin sheath, the Nodes of Ranvier. Myelinated axons transmit impulses through saltatory conduction, in which action potentials “jump” from node to node down the axon. Saltatory conduction is much faster than impulse conduction in unmyelinated axons. Axon diameter also affects conduction speed; thick axons transmit faster than thin axons. Thick, myelinated axons: 120 m/sec. Thin, unmyelinated axons: 0.5 m/sec. ©2019 McGraw-Hill Education.  Figure 10.19 Saltatory Conduction The transmission of a nerve impulse down a myelinated axon in saltatory conduction (도약전도): 전류의 누출이 최소화되어 전도가 빨라짐. 랑비에 결절에서만 전도됨. ©2019 McGraw-Hill Education.